WO2025199048A1

WO2025199048A1 - Mobility procedures in non-terrestrial networks

Info

Publication number: WO2025199048A1
Application number: PCT/US2025/020261
Authority: WO
Inventors: Mohammad Ghadir Khoshkholgh Dashtaki; Ali Cagatay CIRIK; Esmael Hejazi Dinan; Hyoungsuk Jeon; Hua Zhou; Gautham PRASAD; Kyungmin Park
Original assignee: Ofinno LLC
Current assignee: Ofinno LLC
Priority date: 2024-03-18
Filing date: 2025-03-17
Publication date: 2025-09-25
Anticipated expiration: 2026-09-18

Abstract

A wireless device receives, via a first cell, a radio resource control (RRC) reconfiguration message. The RRC reconfiguration message indicates a random access channel (RACH)-less handover to a second cell and a configuration uplink grant indicating an uplink resource for the second cell. The wireless device transmits an uplink transmission via the uplink resource of the second cell. The uplink resource is determined based on a service link propagation delay difference between the first cell and a second cell.

Description

TITLE

Mobility Procedures in Non-terrestrial Networks CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/566,782, filed March 18, 2024, which is hereby incorporated by reference in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Examples of several of the various embodiments of the present disclosure are described herein with reference to the drawings.

[0003] FIG. 1 A and FIG. 1 B illustrate example mobile communication networks in which embodiments of the present disclosure may be implemented.

[0004] FIG. 2A and FIG. 2B respectively illustrate a New Radio (NR) user plane and control plane protocol stack.

[0005] FIG. 3 illustrates an example of services provided between protocol layers of the NR user plane protocol stack of FIG. 2A.

[0006] FIG. 4A illustrates an example downlink data flow through the NR user plane protocol stack of FIG. 2A.

[0007] FIG. 4B illustrates an example format of a MAC subheader in a MAC PDU.

[0008] FIG. 5A and FIG. 5B respectively illustrate a mapping between logical channels, transport channels, and physical channels for the downlink and uplink.

[0009] FIG. 6 is an example diagram showing RRC state transitions of a UE.

[0010] FIG. 7 illustrates an example configuration of an NR frame into which OFDM symbols are grouped.

[0011] FIG. 8 illustrates an example configuration of a slot in the time and frequency domain for an NR carrier.

[0012] FIG. 9 illustrates an example of bandwidth adaptation using three configured BWPs for an NR carrier.

[0013] FIG. 10A illustrates three carrier aggregation configurations with two component carriers.

[0014] FIG. 10B illustrates an example of how aggregated cells may be configured into one or more PUCCH groups.

[0015] FIG. 11A illustrates an example of an SS/PBCH block structure and location.

[0016] FIG. 11B illustrates an example of CSI-RSs that are mapped in the time and frequency domains.

[0017] FIG. 12A and FIG. 12B respectively illustrate examples of three downlink and uplink beam management procedures.

[0018] FIG. 13A, FIG. 13B, and FIG. 13C respectively illustrate a four-step contention-based random access procedure, a two-step contention-free random access procedure, and another two-step random access procedure. [0019] FIG. 14A illustrates an example of CORESET configurations for a bandwidth part.

[0020] FIG. 14B illustrates an example of a COE-to-REG mapping for DOI transmission on a CORESET and PDCCH processing.

[0021] FIG. 15 illustrates an example of a wireless device in communication with a base station. [0022] FIG. 16A, FIG. 16B, FIG. 160, and FIG. 16D illustrate example structures for uplink and downlink transmission.

[0023] FIG. 17A, FIG. 17B, and FIG. 170 illustrate an aspect of an example embodiment according to the present disclosure.

[0024] FIG. 18A and FIG. 18B illustrate an aspect of an example embodiment according to the present disclosure.

[0025] FIG. 19A and FIG. 19B illustrate an aspect of an example embodiment according to the present disclosure.

[0026] FIG. 20 illustrates an aspect of an example embodiment according to the present disclosure.

[0027] FIG. 21A, FIG. 21 B, and FIG. 210 illustrate an aspect of an example embodiment according to the present disclosure.

[0028] FIG. 22 illustrates an aspect of an example embodiment according to the present disclosure.

[0029] FIG. 23 illustrates an aspect of an example embodiment according to the present disclosure.

[0030] FIG. 24 illustrates an aspect of an example embodiment according to the present disclosure.

[0031] FIG. 25 illustrates an aspect of an example embodiment according to the present disclosure.

[0032] FIG. 26 illustrates an aspect of an example embodiment according to the present disclosure.

[0033] FIG. 27 illustrates an aspect of an example embodiment according to the present disclosure.

[0034] FIG. 28 illustrates an aspect of an example embodiment according to the present disclosure.

[0035] FIG. 29 illustrates an aspect of an example embodiment according to the present disclosure.

[0036] FIG. 30 illustrates an aspect of an example embodiment according to the present disclosure.

[0037] FIG. 31 illustrates an aspect of an example embodiment according to the present disclosure.

[0038] FIG. 32 illustrates an aspect of an example embodiment according to the present disclosure.

[0039] FIG. 33 illustrates an aspect of an example embodiment according to the present disclosure.

[0040] FIG. 34 illustrates an aspect of an example embodiment according to the present disclosure.

[0041] FIG. 35 illustrates an aspect of an example embodiment according to the present disclosure.

[0042] FIG. 36 illustrates an aspect of an example embodiment according to the present disclosure.

[0043] FIG. 37 illustrates an aspect of an example embodiment according to the present disclosure.

[0044] FIG. 38 illustrates an aspect of an example embodiment according to the present disclosure.

[0045] FIG. 39 illustrates an aspect of an example embodiment according to the present disclosure.

[0046] FIG. 40A, FIG. 40B, and FIG. 400 illustrate an aspect of an example embodiment according to the present disclosure.

[0047] FIG. 41A, FIG. 41 B, and FIG. 410 illustrate an aspect of an example embodiment according to the present disclosure.

[0048] FIG. 42A and FIG. 42B illustrate an aspect of an example embodiment according to the present disclosure.

[0049] FIG. 43A and FIG. 43B illustrate an aspect of an example embodiment according to the present disclosure.

[0050] FIG. 44 illustrates an aspect of an example embodiment according to the present disclosure. [0051] FIG. 45 illustrates an aspect of an example embodiment according to the present disclosure.

DETAILED DESCRIPTION

[0052] In the present disclosure, various embodiments are presented as examples of how the disclosed techniques may be implemented and/or how the disclosed techniques may be practiced in environments and scenarios. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the scope. In fact, after reading the description, it will be apparent to one skilled in the relevant art how to implement alternative embodiments. The present embodiments should not be limited by any of the described exemplary embodiments. The embodiments of the present disclosure will be described with reference to the accompanying drawings. Limitations, features, and/or elements from the disclosed example embodiments may be combined to create further embodiments within the scope of the disclosure. Any figures which highlight the functionality and advantages, are presented for example purposes only. The disclosed architecture is sufficiently flexible and configurable, such that it may be utilized in ways other than that shown. For example, the actions listed in any flowchart may be re-ordered or only optionally used in some embodiments.

[0053] Embodiments may be configured to operate as needed. The disclosed mechanism may be performed when certain criteria are met, for example, in a wireless device, a base station, a radio environment, a network, a combination of the above, and/or the like. Example criteria may be based, at least in part, on for example, wireless device or network node configurations, traffic load, initial system set up, packet sizes, traffic characteristics, a combination of the above, and/or the like. When the one or more criteria are met, various example embodiments may be applied. Therefore, it may be possible to implement example embodiments that selectively implement disclosed protocols.

[0054] A base station may communicate with a mix of wireless devices. Wireless devices and/or base stations may support multiple technologies, and/or multiple releases of the same technology. Wireless devices may have some specific capability(ies) depending on wireless device category and/or capability(ies). When this disclosure refers to a base station communicating with a plurality of wireless devices, this disclosure may refer to a subset of the total wireless devices in a coverage area. This disclosure may refer to, for example, a plurality of wireless devices of a given LTE or 5G release with a given capability and in a given sector of the base station. The plurality of wireless devices in this disclosure may refer to a selected plurality of wireless devices, and/or a subset of total wireless devices in a coverage area which perform according to disclosed methods, and/or the like. There may be a plurality of base stations or a plurality of wireless devices in a coverage area that may not comply with the disclosed methods, for example, those wireless devices or base stations may perform based on older releases of LTE or 5G technology.

[0055] In this disclosure, “a” and “an” and similar phrases are to be interpreted as “at least one” and “one or more.” Similarly, any term that ends with the suffix “(s)” is to be interpreted as “at least one” and “one or more.” In this disclosure, the term “may” is to be interpreted as “may, for example.” In other words, the term “may” is indicative that the phrase following the term “may” is an example of one of a multitude of suitable possibilities that may, or may not, be employed by one or more of the various embodiments. The terms “comprises” and “consists of”, as used herein, enumerate one or more components of the element being described. The term “comprises” is interchangeable with “includes” and does not exclude unenumerated components from being included in the element being described. By contrast, “consists of” provides a complete enumeration of the one or more components of the element being described. The term “based on”, as used herein, should be interpreted as “based at least in part on” rather than, for example, “based solely on”. The term “and/or” as used herein represents any possible combination of enumerated elements. For example, “A, B, and/or C” may represent A; B; C; A and B; A and C; B and C; or A, B, and C.

[0056] If A and B are sets and every element of A is an element of B, A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B = {celH , cell2} are: {celH }, {cell2}, and {celH , cell2}. The phrase “based on” (or equally “based at least on”) is indicative that the phrase following the term “based on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “in response to” (or equally “in response at least to”) is indicative that the phrase following the phrase “in response to” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “depending on” (or equally “depending at least to”) is indicative that the phrase following the phrase “depending on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “employin g/using” (or equally “employing/using at least”) is indicative that the phrase following the phrase

“employin g/using” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments.

[0057] The term configured may relate to the capacity of a device whether the device is in an operational or non- operational state. Configured may refer to specific settings in a device that affect or implement the operational characteristics of the device whether the device is in an operational or non-operational state. In other words, the hardware, software, firmware, registers, memory values, and/or the like may be “configured” within a device, whether the device is in an operational or nonoperational state, to provide the device with specific characteristics. Terms such as “a control message to cause in a device” may mean that a control message has parameters that may be used to configure specific characteristics or may be used to implement certain actions in the device, whether the device is in an operational or non-operational state.

[0058] In this disclosure, parameters (or equally called, fields, or Information elements: lEs) may comprise one or more information objects, and an information object may comprise one or more other objects. For example, if parameter (IE) N comprises parameter (IE) M, and parameter (IE) M comprises parameter (IE) K, and parameter (IE) K comprises parameter (information element) J. Then, for example, N comprises K, and N comprises J. In an example embodiment, when one or more messages comprise a plurality of parameters, it implies that a parameter in the plurality of parameters is in at least one of the one or more messages, but does not have to be in each of the one or more messages. [0059] Many features presented are described as being optional through the use of “may” or the use of parentheses. For the sake of brevity and legibility, the present disclosure does not explicitly recite each and every permutation that may be obtained by choosing from the set of optional features. The present disclosure is to be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features may be embodied in seven ways, namely with just one of the three possible features, with any two of the three possible features or with three of the three possible features.

[0060] Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined here as an element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software in combination with hardware, firmware, wetware (e.g. hardware with a biological element) or a combination thereof, which may be behaviorally equivalent. For example, modules may be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, MATLAB or the like) or a modeling/simulation program such as Simulink, Stateflow, GNU Octave, or LabVI EWMathScript. It may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and/or quantum hardware. Examples of programmable hardware comprise: computers, microcontrollers, microprocessors, applicationspecific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (OPLDs). Computers, microcontrollers and microprocessors are programmed using languages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. The mentioned technologies are often used in combination to achieve the result of a functional module.

[0061] FIG. 1A illustrates an example of a mobile communication network 100 in which embodiments of the present disclosure may be implemented. The mobile communication network 100 may be, for example, a public land mobile network (PLMN) run by a network operator. As illustrated in FIG. 1A, the mobile communication network 100 includes a core network (CN) 102, a radio access network (RAN) 104, and a wireless device 106.

[0062] The CN 102 may provide the wireless device 106 with an interface to one or more data networks (DNs), such as public DNs (e.g., the Internet), private DNs, and/or intra-operator DNs. As part of the interface functionality, the CN 102 may set up end-to-end connections between the wireless device 106 and the one or more DNs, authenticate the wireless device 106, and provide charging functionality.

[0063] The RAN 104 may connect the CN 102 to the wireless device 106 through radio communications over an air interface. As part of the radio communications, the RAN 104 may provide scheduling, radio resource management, and retransmission protocols. The communication direction from the RAN 104 to the wireless device 106 over the air interface is known as the downlink and the communication direction from the wireless device 106 to the RAN 104 over the air interface is known as the uplink. Downlink transmissions may be separated from uplink transmissions using frequency division duplexing (FDD), time-division duplexing (TDD), and/or some combination of the two duplexing techniques.

[0064] The term wireless device may be used throughout this disclosure to refer to and encompass any mobile device or fixed (non-mobile) device for which wireless communication is needed or usable. For example, a wireless device may be a telephone, smart phone, tablet, computer, laptop, sensor, meter, wearable device, Internet of Things (loT) device, vehicle roadside unit (RSU), relay node, automobile, and/or any combination thereof. The term wireless device encompasses other terminology, including user equipment (UE), user terminal (UT), access terminal (AT), mobile station, handset, wireless transmit and receive unit (WTRU), and/or wireless communication device.

[0065] The RAN 104 may include one or more base stations (not shown). The term base station may be used throughout this disclosure to refer to and encompass a Node B (associated with UMTS and/or 3G standards), an Evolved Node B (eNB, associated with E-UTRA and/or 4G standards), a remote radio head (RRH), a baseband processing unit coupled to one or more RRHs, a repeater node or relay node used to extend the coverage area of a donor node, a Next Generation Evolved Node B (ng-eNB), a Generation Node B (gNB, associated with NR and/or 5G standards), an access point (AP, associated with, for example, Wi-Fi or any other suitable wireless communication standard), and/or any combination thereof. A base station may comprise at least one gNB Central Unit (gNB-CU) and at least one a gNB Distributed Unit (gNB-DU).

[0066] A base station included in the RAN 104 may include one or more sets of antennas for communicating with the wireless device 106 over the air interface. For example, one or more of the base stations may include three sets of antennas to respectively control three cells (or sectors). The size of a cell may be determined by a range at which a receiver (e.g., a base station receiver) can successfully receive the transmissions from a transmitter (e.g., a wireless device transmitter) operating in the cell. Together, the cells of the base stations may provide radio coverage to the wireless device 106 over a wide geographic area to support wireless device mobility.

[0067] In addition to three-sector sites, other implementations of base stations are possible. For example, one or more of the base stations in the RAN 104 may be implemented as a sectored site with more or less than three sectors. One or more of the base stations in the RAN 104 may be implemented as an access point, as a baseband processing unit coupled to several remote radio heads (RRHs), and/or as a repeater or relay node used to extend the coverage area of a donor node. A baseband processing unit coupled to RRHs may be part of a centralized or cloud RAN architecture, where the baseband processing unit may be either centralized in a pool of baseband processing units or virtualized. A repeater node may amplify and rebroadcast a radio signal received from a donor node. A relay node may perform the same/similar functions as a repeater node but may decode the radio signal received from the donor node to remove noise before amplifying and rebroadcasting the radio signal.

[0068] The RAN 104 may be deployed as a homogenous network of macrocell base stations that have similar antenna patterns and similar high-level transmit powers. The RAN 104 may be deployed as a heterogeneous network. In heterogeneous networks, small cell base stations may be used to provide small coverage areas, for example, coverage areas that overlap with the comparatively larger coverage areas provided by macrocell base stations. The small coverage areas may be provided in areas with high data traffic (or so-called “hotspots”) or in areas with weak macrocell coverage. Examples of small cell base stations include, in order of decreasing coverage area, microcell base stations, picocell base stations, and femtocell base stations or home base stations.

[0069] The Third-Generation Partnership Project (3GPP) was formed in 1998 to provide global standardization of specifications for mobile communication networks similar to the mobile communication network 100 in FIG. 1A. To date, 3GPP has produced specifications for three generations of mobile networks: a third generation (3G) network known as Universal Mobile Telecommunications System (UMTS), a fourth generation (4G) network known as Long-Term Evolution (LTE), and a fifth generation (5G) network known as 5G System (5GS). Embodiments of the present disclosure are described with reference to the RAN of a 3GPP 5G network, referred to as next-generation RAN (NG- RAN). Embodiments may be applicable to RANs of other mobile communication networks, such as the RAN 104 in FIG. 1 A, the RANs of earlier 3G and 4G networks, and those of future networks yet to be specified (e.g., a 3GPP 6G network). NG-RAN implements 5G radio access technology known as New Radio (NR) and may be provisioned to implement 4G radio access technology or other radio access technologies, including non-3GPP radio access technologies.

[0070] FIG. 1 B illustrates another example mobile communication network 150 in which embodiments of the present disclosure may be implemented. Mobile communication network 150 may be, for example, a PLMN run by a network operator. As illustrated in FIG. 1B, mobile communication network 150 includes a 5G core network (5G-CN) 152, an NG-RAN 154, and UEs 156A and 156B (collectively UEs 156). These components may be implemented and operate in the same or similar manner as corresponding components described with respect to FIG. 1A.

[0071] The 5G-CN 152 provides the UEs 156 with an interface to one or more DNs, such as public DNs (e.g., the Internet), private DNs, and/or intra-operator DNs. As part of the interface functionality, the 5G-CN 152 may set up end- to-end connections between the UEs 156 and the one or more DNs, authenticate the UEs 156, and provide charging functionality. Compared to the ON of a 3GPP 4G network, the basis of the 5G-CN 152 may be a service-based architecture. This means that the architecture of the nodes making up the 5G-CN 152 may be defined as network functions that offer services via interfaces to other network functions. The network functions of the 5G-CN 152 may be implemented in several ways, including as network elements on dedicated or shared hardware, as software instances running on dedicated or shared hardware, or as virtualized functions instantiated on a platform (e.g., a cloud-based platform).

[0072] As illustrated in FIG. 1B, the 5G-CN 152 includes an Access and Mobility Management Function (AMF) 158A and a User Plane Function (UPF) 158B, which are shown as one component AMF/UPF 158 in FIG. 1 B for ease of illustration. The UPF 158B may serve as a gateway between the NG-RAN 154 and the one or more DNs. The UPF 158B may perform functions such as packet routing and forwarding, packet inspection and user plane policy rule enforcement, traffic usage reporting, uplink classification to support routing of traffic flows to the one or more DNs, quality of service (QoS) handling for the user plane (e.g. , packet filtering, gating, uplink/downlink rate enforcement, and uplink traffic verification), downlink packet buffering, and downlink data notification triggering. The UPF 158B may serve as an anchor point for intra-Zinter-Radio Access Technology (RAT) mobility, an external protocol (or packet) data unit (PDU) session point of interconnect to the one or more DNs, and/or a branching point to support a multi-homed PDU session. The UEs 156 may be configured to receive services through a PDU session, which is a logical connection between a UE and a DN.

[0073] The AMF 158A may perform functions such as Non-Access Stratum (NAS) signaling termination, NAS signaling security, Access Stratum (AS) security control, inter-CN node signaling for mobility between 3GPP access networks, idle mode UE reachability (e.g., control and execution of paging retransmission), registration area management, intra-system and inter-system mobility support, access authentication, access authorization including checking of roaming rights, mobility management control (subscription and policies), network slicing support, and/or session management function (SMF) selection. NAS may refer to the functionality operating between a ON and a UE, and AS may refer to the functionality operating between the UE and a RAN.

[0074] The 5G-CN 152 may include one or more additional network functions that are not shown in FIG. 1B for the sake of clarity. For example, the 5G-CN 152 may include one or more of a Session Management Function (SMF), an NR Repository Function (NRF), a Policy Control Function (PCF), a Network Exposure Function (NEF), a Unified Data Management (UDM), an Application Function (AF), and/or an Authentication Server Function (AUSF).

[0075] The NG-RAN 154 may connect the 5G-CN 152 to the UEs 156 through radio communications over the air interface. The NG-RAN 154 may include one or more gNBs, illustrated as gNB 160A and gNB 160B (collectively gNBs 160) and/or one or more ng-eNBs, illustrated as ng-eNB 162A and ng-eNB 162B (collectively ng-eNBs 162). The gNBs 160 and ng-eNBs 162 may be more generically referred to as base stations. The gNBs 160 and ng-eNBs 162 may include one or more sets of antennas for communicating with the UEs 156 over an air interface. For example, one or more of the gNBs 160 and/or one or more of the ng-eNBs 162 may include three sets of antennas to respectively control three cells (or sectors). Together, the cells of the gNBs 160 and the ng-eNBs 162 may provide radio coverage to the UEs 156 over a wide geographic area to support UE mobility.

[0076] As shown in FIG. 1 B, the gNBs 160 and/or the ng-eNBs 162 may be connected to the 5G-CN 152 by means of an NG interface and to other base stations by an Xn interface. The NG and Xn interfaces may be established using direct physical connections and/or indirect connections over an underlying transport network, such as an internet protocol (IP) transport network. The gNBs 160 and/or the ng-eNBs 162 may be connected to the UEs 156 by means of a Uu interface. For example, as illustrated in FIG. 1B, gNB 160A may be connected to the UE 156A by means of a Uu interface. The NG, Xn, and Uu interfaces are associated with a protocol stack. The protocol stacks associated with the interfaces may be used by the network elements in FIG. 1 B to exchange data and signaling messages and may include two planes: a user plane and a control plane. The user plane may handle data of interest to a user. The control plane may handle signaling messages of interest to the network elements. [0077] The gNBs 160 and/or the ng-eNBs 162 may be connected to one or more AMF/UPF functions of the 5G-CN 152, such as the AMF/UPF 158, by means of one or more NG interfaces. For example, the gNB 160A may be connected to the UPF 158B of the AMF/UPF 158 by means of an NG-User plane (NG-U) interface. The NG-U interface may provide delivery (e.g., non-guaranteed delivery) of user plane PDUs between the gNB 160A and the UPF 158B. The gNB 160A may be connected to the AMF 158A by means of an NG-Control plane (NG-C) interface. The NG-0 interface may provide, for example, NG interface management, UE context management, UE mobility management, transport of NAS messages, paging, PDU session management, and configuration transfer and/or warning message transmission.

[0078] The gNBs 160 may provide NR user plane and control plane protocol terminations towards the UEs 156 over the Uu interface. For example, the gNB 160A may provide NR user plane and control plane protocol terminations toward the UE 156A over a Uu interface associated with a first protocol stack. The ng-eNBs 162 may provide Evolved UMTS Terrestrial Radio Access (E-UTRA) user plane and control plane protocol terminations towards the UEs 156 over a Uu interface, where E-UTRA refers to the 3GPP 4G radio-access technology. For example, the ng-eNB 162B may provide E-UTRA user plane and control plane protocol terminations towards the UE 156B over a Uu interface associated with a second protocol stack.

[0079] The 5G-CN 152 was described as being configured to handle NR and 4G radio accesses. It will be appreciated by one of ordinary skill in the art that it may be possible for NR to connect to a 4G core network in a mode known as “non-standalone operation.” In non-standalone operation, a 4G core network is used to provide (or at least support) control-plane functionality (e.g., initial access, mobility, and paging). Although only one AMF/UPF 158 is shown in FIG. 1 B, one gNB or ng-eNB may be connected to multiple AMF/UPF nodes to provide redundancy and/or to load share across the multiple AMF/UPF nodes.

[0080] As discussed, an interface (e.g., Uu, Xn, and NG interfaces) between the network elements in FIG. 1 B may be associated with a protocol stack that the network elements use to exchange data and signaling messages. A protocol stack may include two planes: a user plane and a control plane. The user plane may handle data of interest to a user, and the control plane may handle signaling messages of interest to the network elements.

[0081] FIG. 2A and FIG. 2B respectively illustrate examples of NR user plane and NR control plane protocol stacks for the Uu interface that lies between a UE 210 and a gNB 220. The protocol stacks illustrated in FIG. 2A and FIG. 2B may be the same or similar to those used for the Uu interface between, for example, the UE 156A and the gNB 160A shown in FIG. 1B.

[0082] FIG. 2A illustrates a NR user plane protocol stack comprising five layers implemented in the UE 210 and the gNB 220. At the bottom of the protocol stack, physical layers (PHYs) 211 and 221 may provide transport services to the higher layers of the protocol stack and may correspond to layer 1 of the Open Systems Interconnection (OSI) model. The next four protocols above PHYs 211 and 221 comprise media access control layers (MAGs) 212 and 222, radio link control layers (RLCs) 213 and 223, packet data convergence protocol layers (PDOPs) 214 and 224, and service data application protocol layers (SDAPs) 215 and 225. Together, these four protocols may make up layer 2, or the data link layer, of the OSI model.

[0083] FIG. 3 illustrates an example of services provided between protocol layers of the NR user plane protocol stack. Starting from the top of FIG. 2A and FIG. 3, the SDAPs 215 and 225 may perform QoS flow handling. The UE 210 may receive services through a PDU session, which may be a logical connection between the UE 210 and a DN. The PDU session may have one or more QoS flows. A UPF of a CN (e.g., the UPF 158B) may map IP packets to the one or more QoS flows of the PDU session based on QoS requirements (e.g., in terms of delay, data rate, and/or error rate). The SDAPs 215 and 225 may perform mapping/de-mapping between the one or more QoS flows and one or more data radio bearers. The mapping/de-mapping between the QoS flows and the data radio bearers may be determined by the SDAP 225 at the gNB 220. The SDAP 215 at the UE 210 may be informed of the mapping between the QoS flows and the data radio bearers through reflective mapping or control signaling received from the gNB 220. For reflective mapping, the SDAP 225 at the gNB 220 may mark the downlink packets with a QoS flow indicator (QFI), which may be observed by the SDAP 215 at the UE 210 to determine the mapping/de-mapping between the QoS flows and the data radio bearers.

[0084] The PDCPs 214 and 224 may perform header compression/decompression to reduce the amount of data that needs to be transmitted over the air interface, ciphering/deciphering to prevent unauthorized decoding of data transmitted over the air interface, and integrity protection (to ensure control messages originate from intended sources. The PDCPs 214 and 224 may perform retransmissions of undelivered packets, in-sequence delivery and reordering of packets, and removal of packets received in duplicate due to, for example, an intra-gNB handover. The PDCPs 214 and 224 may perform packet duplication to improve the likelihood of the packet being received and, at the receiver, remove any duplicate packets. Packet duplication may be useful for services that require high reliability.

[0085] Although not shown in FIG. 3, PDCPs 214 and 224 may perform mapping/de-mapping between a split radio bearer and RLC channels in a dual connectivity scenario. Dual connectivity is a technique that allows a UE to connect to two cells or, more generally, two cell groups: a master cell group (MCG) and a secondary cell group (SCG). A split bearer is when a single radio bearer, such as one of the radio bearers provided by the PDCPs 214 and 224 as a service to the SDAPs 215 and 225, is handled by cell groups in dual connectivity. The PDCPs 214 and 224 may map/de-map the split radio bearer between RLC channels belonging to cell groups.

[0086] The RLCs 213 and 223 may perform segmentation, retransmission through Automatic Repeat Request (ARQ), and removal of duplicate data units received from MACs 212 and 222, respectively. The RLCs 213 and 223 may support three transmission modes: transparent mode (TM); unacknowledged mode (UM); and acknowledged mode (AM). Based on the transmission mode an RLC is operating, the RLC may perform one or more of the noted functions. The RLC configuration may be per logical channel with no dependency on numerologies and/or Transmission Time Interval (TTI) durations. As shown in FIG. 3, the RLCs 213 and 223 may provide RLC channels as a service to PDCPs 214 and 224, respectively. [0087] The MAGs 212 and 222 may perform multiplexing/demultiplexing of logical channels and/or mapping between logical channels and transport channels. The multiplexing/demultiplexing may include multiplexing/demultiplexing of data units, belonging to the one or more logical channels, into/from Transport Blocks (TBs) delivered to/from the PHYs

211 and 221. The MAC 222 may be configured to perform scheduling, scheduling information reporting, and priority handling between UEs by means of dynamic scheduling. Scheduling may be performed in the g N B 220 (at the MAC 222) for downlink and uplink. The MACs 212 and 222 may be configured to perform error correction through Hybrid Automatic Repeat Request (HARQ) (e.g., one HARQ entity per carrier in case of Carrier Aggregation (CA)), priority handling between logical channels of the UE 210 by means of logical channel prioritization, and/or padding. The MACs

212 and 222 may support one or more numerologies and/or transmission timings. In an example, mapping restrictions in a logical channel prioritization may control which numerology and/or transmission timing a logical channel may use. As shown in FIG. 3, the MACs 212 and 222 may provide logical channels as a service to the RLCs 213 and 223.

[0088] The PHYs 211 and 221 may perform mapping of transport channels to physical channels and digital and analog signal processing functions for sending and receiving information over the air interface. These digital and analog signal processing functions may include, for example, coding/decoding and modulation/demodulation. The PHYs 211 and 221 may perform multi-antenna mapping. As shown in FIG. 3, the PHYs 211 and 221 may provide one or more transport channels as a service to the MACs 212 and 222.

[0089] FIG. 4A illustrates an example downlink data flow through the NR user plane protocol stack. FIG. 4A illustrates a downlink data flow of three IP packets (n, n+1, and m) through the NR user plane protocol stack to generate two TBs at the gNB 220. An uplink data flow through the NR user plane protocol stack may be similar to the downlink data flow depicted in FIG. 4A.

[0090] The downlink data flow of FIG. 4A begins when SDAP 225 receives the three IP packets from one or more QoS flows and maps the three packets to radio bearers. In FIG. 4A, the SDAP 225 maps IP packets n and n+1 to a first radio bearer 402 and maps IP packet m to a second radio bearer 404. An SDAP header (labeled with an “H” in FIG. 4A) is added to an IP packet. The data unit from/to a higher protocol layer is referred to as a service data unit (SDU) of the lower protocol layer and the data unit to/from a lower protocol layer is referred to as a protocol data unit (PDU) of the higher protocol layer. As shown in FIG. 4A, the data unit from the SDAP 225 is an SDU of lower protocol layer PDCP 224 and is a PDU of the SDAP 225.

[0091] The remaining protocol layers in FIG. 4A may perform their associated functionality (e.g., with respect to FIG. 3), add corresponding headers, and forward their respective outputs to the next lower layer. For example, the PDCP 224 may perform IP-header compression and ciphering and forward its output to the RLC 223. The RLC 223 may optionally perform segmentation (e.g., as shown for IP packet m in FIG. 4A) and forward its output to the MAC 222. The MAC 222 may multiplex a number of RLC PDUs and may attach a MAC subheader to an RLC PDU to form a transport block. In NR, the MAC subheaders may be distributed across the MAC PDU, as illustrated in FIG. 4A. In LTE, the MAC subheaders may be entirely located at the beginning of the MAC PDU. The NR MAC PDU structure may reduce processing time and associated latency because the MAC PDU subheaders may be computed before the full MAC PDU is assembled.

[0092] FIG. 4B illustrates an example format of a MAC subheader in a MAC PDU. The MAC subheader includes: an SDU length field for indicating the length (e.g. , in bytes) of the MAC SDU to which the MAC subheader corresponds; a logical channel identifier (LCID) field for identifying the logical channel from which the MAC SDU originated to aid in the demultiplexing process; a flag (F) for indicating the size of the SDU length field; and a reserved bit (R) field for future use.

[0093] FIG. 4B further illustrates MAC control elements (CEs) inserted into the MAC PDU by a MAC, such as MAC 223 or MAC 222. For example, FIG. 4B illustrates two MAC CEs inserted into the MAC PDU. MAC CEs may be inserted at the beginning of a MAC PDU for downlink transmissions (as shown in FIG. 4B) and at the end of a MAC PDU for uplink transmissions. MAC CEs may be used for in-band control signaling. Example MAC CEs include: scheduling-related MAC CEs, such as buffer status reports and power headroom reports; activation/deactivation MAC CEs, such as those for activation/deactivation of PDCP duplication detection, channel state information (CSI) reporting, sounding reference signal (SRS) transmission, and prior configured components; discontinuous reception (DRX) related MAC CEs; timing advance MAC CEs; and random access related MAC CEs. A MAC CE may be preceded by a MAC subheader with a similar format as described for MAC SDUs and may be identified with a reserved value in the LCID field that indicates the type of control information included in the MAC CE.

[0094] Before describing the NR control plane protocol stack, logical channels, transport channels, and physical channels are first described as well as a mapping between the channel types. One or more of the channels may be used to carry out functions associated with the NR control plane protocol stack described later below.

[0095] FIG. 5A and FIG. 5B illustrate, for downlink and uplink respectively, a mapping between logical channels, transport channels, and physical channels. Information is passed through channels between the RLC, the MAC, and the PHY of the NR protocol stack. A logical channel may be used between the RLC and the MAC and may be classified as a control channel that carries control and configuration information in the NR control plane or as a traffic channel that carries data in the NR user plane. A logical channel may be classified as a dedicated logical channel that is dedicated to a specific UE or as a common logical channel that may be used by more than one UE. A logical channel may also be defined by the type of information it carries. The set of logical channels defined by NR include, for example: [0096] - a paging control channel (POOH) for carrying paging messages used to page a UE whose location is not known to the network on a cell level;

[0097] - a broadcast control channel (BOOH) for carrying system information messages in the form of a master information block (MIB) and several system information blocks (SIBs), wherein the system information messages may be used by the UEs to obtain information about how a cell is configured and how to operate within the cell;

[0098] - a common control channel (COCH) for carrying control messages together with random access; [0099] - a dedicated control channel (DCCH) for carrying control messages to/from a specific the UE to configure the UE; and

[0100] - a dedicated traffic channel (DTCH) for carrying user data to/from a specific the UE.

[0101] Transport channels are used between the MAC and PHY layers and may be defined by how the information they carry is transmitted over the air interface. The set of transport channels defined by NR include, for example: [0102] - a paging channel (PCH) for carrying paging messages that originated from the PCCH;

[0103] - a broadcast channel (BOH) for carrying the MIB from the BCCH;

[0104] - a downlink shared channel (DL-SCH) for carrying downlink data and signaling messages, including the SIBs from the BCCH;

[0105] -- an uplink shared channel (UL-SCH) for carrying uplink data and signaling messages; and

[0106] - a random access channel (RACH) for allowing a UE to contact the network without any prior scheduling.

[0107] The PHY may use physical channels to pass information between processing levels of the PHY. A physical channel may have an associated set of time-frequency resources for carrying the information of one or more transport channels. The PHY may generate control information to support the low-level operation of the PHY and provide the control information to the lower levels of the PHY via physical control channels, known as L1/L2 control channels. The set of physical channels and physical control channels defined by NR include, for example:

[0108] -- a physical broadcast channel (PBOH) for carrying the MIB from the BOH;

[0109] -- a physical downlink shared channel (PDSCH) for carrying downlink data and signaling messages from the DL-SCH, as well as paging messages from the PCH;

[0110] -- a physical downlink control channel (PDCCH) for carrying downlink control information (DCI), which may include downlink scheduling commands, uplink scheduling grants, and uplink power control commands;

[0111] -- a physical uplink shared channel (PUSCH) for carrying uplink data and signaling messages from the UL- SCH and in some instances uplink control information (UCI) as described below;

[0112] -- a physical uplink control channel (PUCCH) for carrying UCI, which may include HARQ acknowledgments, channel quality indicators (CQI), pre-coding matrix indicators (PMI), rank indicators (Rl), and scheduling requests (SR); and

[0113] -- a physical random access channel (PRACH) for random access.

[0114] Similar to the physical control channels, the physical layer generates physical signals to support the low-level operation of the physical layer. As shown in FIG. 5A and FIG. 5B, the physical layer signals defined by NR include: primary synchronization signals (PSS), secondary synchronization signals (SSS), channel state information reference signals (CSI-RS), demodulation reference signals (DMRS), sounding reference signals (SRS), and phase-tracking reference signals (PT-RS). These physical layer signals will be described in greater detail below.

[0115] FIG. 2B illustrates an example NR control plane protocol stack. As shown in FIG. 2B, the NR control plane protocol stack may use the same/similar first four protocol layers as the example NR user plane protocol stack. These four protocol layers include the PHYs 211 and 221 , the MAGs 212 and 222, the RLCs 213 and 223, and the PDOPs 214 and 224. Instead of having the SDAPs 215 and 225 at the top of the stack as in the NR user plane protocol stack, the NR control plane stack has radio resource controls (RRCs) 216 and 226 and NAS protocols 217 and 237 at the top of the NR control plane protocol stack.

[0116] The NAS protocols 217 and 237 may provide control plane functionality between the UE 210 and the AMF 230 (e.g., the AMF 158A) or, more generally, between the UE 210 and the ON. The NAS protocols 217 and 237 may provide control plane functionality between the UE 210 and the AMF 230 via signaling messages, referred to as NAS messages. There is no direct path between the UE 210 and the AMF 230 through which the NAS messages can be transported. The NAS messages may be transported using the AS of the Uu and NG interfaces. NAS protocols 217 and 237 may provide control plane functionality such as authentication, security, connection setup, mobility management, and session management.

[0117] The RRCs 216 and 226 may provide control plane functionality between the UE 210 and the gNB 220 or, more generally, between the UE 210 and the RAN. The RRCs 216 and 226 may provide control plane functionality between the UE 210 and the gNB 220 via signaling messages, referred to as RRC messages. RRC messages may be transmitted between the UE 210 and the RAN using signaling radio bearers and the same/similar PDCP, RLC, MAC, and PHY protocol layers. The MAC may multiplex control-plane and user-plane data into the same transport block (TB). The RRCs 216 and 226 may provide control plane functionality such as: broadcast of system information related to AS and NAS; paging initiated by the CN or the RAN; establishment, maintenance and release of an RRC connection between the UE 210 and the RAN; security functions including key management; establishment, configuration, maintenance and release of signaling radio bearers and data radio bearers; mobility functions; QoS management functions; the UE measurement reporting and control of the reporting; detection of and recovery from radio link failure (RLF); and/or NAS message transfer. As part of establishing an RRC connection, RRCs 216 and 226 may establish an RRC context, which may involve configuring parameters for communication between the UE 210 and the RAN.

[0118] FIG. 6 is an example diagram showing RRC state transitions of a UE. The UE may be the same or similar to the wireless device 106 depicted in FIG. 1A, the UE 210 depicted in FIG. 2A and FIG. 2B, or any other wireless device described in the present disclosure. As illustrated in FIG. 6, a UE may be in at least one of three RRC states: RRC connected 602 (e.g., RRC_CONNECTED), RRC idle 604 (e.g., RRC_I DLE), and RRC inactive 606 (e.g., RRCJNACTIVE).

[0119] In RRC connected 602, the UE has an established RRC context and may have at least one RRC connection with a base station. The base station may be similar to one of the one or more base stations included in the RAN 104 depicted in FIG. 1A, one of the gNBs 160 or ng-eNBs 162 depicted in FIG. 1 B, the gNB 220 depicted in FIG. 2A and FIG. 2B, or any other base station described in the present disclosure. The base station with which the UE is connected may have the RRC context for the UE. The RRC context, referred to as the UE context, may comprise parameters for communication between the UE and the base station. These parameters may include, for example: one or more AS contexts; one or more radio link configuration parameters; bearer configuration information (e.g., relating to a data radio bearer, signaling radio bearer, logical channel, QoS flow, and/or PDU session); security information; and/or PHY, MAC, RLC, PDCP, and/or SDAP layer configuration information. While in RRC connected 602, mobility of the UE may be managed by the RAN (e.g., the RAN 104 or the NG-RAN 154). The UE may measure the signal levels (e.g., reference signal levels) from a serving cell and neighboring cells and report these measurements to the base station currently serving the UE. The UE’s serving base station may request a handover to a cell of one of the neighboring base stations based on the reported measurements. The RRC state may transition from RRC connected 602 to RRC idle 604 through a connection release procedure 608 or to RRC inactive 606 through a connection inactivation procedure 610. [0120] In RRC idle 604, an RRC context may not be established for the UE. In RRC idle 604, the UE may not have an RRC connection with the base station. While in RRC idle 604, the UE may be in a sleep state for the majority of the time (e.g., to conserve battery power). The UE may wake up periodically (e.g., once in every discontinuous reception cycle) to monitor for paging messages from the RAN. Mobility of the UE may be managed by the UE through a procedure known as cell reselection. The RRC state may transition from RRC idle 604 to RRC connected 602 through a connection establishment procedure 612, which may involve a random access procedure as discussed in greater detail below.

[0121] In RRC inactive 606, the RRC context previously established is maintained in the UE and the base station. This allows for a fast transition to RRC connected 602 with reduced signaling overhead as compared to the transition from RRC idle 604 to RRC connected 602. While in RRC inactive 606, the UE may be in a sleep state and mobility of the UE may be managed by the UE through cell reselection. The RRC state may transition from RRC inactive 606 to RRC connected 602 through a connection resume procedure 614 or to RRC idle 604 though a connection release procedure 616 that may be the same as or similar to connection release procedure 608.

[0122] An RRC state may be associated with a mobility management mechanism. In RRC idle 604 and RRC inactive 606, mobility is managed by the UE through cell reselection. The purpose of mobility management in RRC idle 604 and RRC inactive 606 is to allow the network to be able to notify the UE of an event via a paging message without having to broadcast the paging message over the entire mobile communications network. The mobility management mechanism used in RRC idle 604 and RRC inactive 606 may allow the network to track the UE on a cell-group level so that the paging message may be broadcast over the cells of the cell group that the UE currently resides within instead of the entire mobile communication network. The mobility management mechanisms for RRC idle 604 and RRC inactive 606 track the UE on a cell-group level. They may do so using different granularities of grouping. For example, there may be three levels of cell-grouping granularity: individual cells; cells within a RAN area identified by a RAN area identifier (RAI); and cells within a group of RAN areas, referred to as a tracking area and identified by a tracking area identifier (TAI).

[0123] T racking areas may be used to track the UE at the CN level. The CN (e.g., the CN 102 or the 5G-CN 152) may provide the UE with a list of TAIs associated with a UE registration area. If the UE moves, through cell reselection, to a cell associated with a TAI not included in the list of TAIs associated with the UE registration area, the UE may perform a registration update with the ON to allow the ON to update the UE’s location and provide the UE with a new the UE registration area.

[0124] RAN areas may be used to track the UE at the RAN level. For a UE in RRC inactive 606 state, the UE may be assigned a RAN notification area. A RAN notification area may comprise one or more cell identities, a list of RAIs, or a list of TAIs. In an example, a base station may belong to one or more RAN notification areas. In an example, a cell may belong to one or more RAN notification areas. If the UE moves, through cell reselection, to a cell not included in the RAN notification area assigned to the UE, the UE may perform a notification area update with the RAN to update the UE’s RAN notification area.

[0125] A base station storing an RRC context for a UE or a last serving base station of the UE may be referred to as an anchor base station. An anchor base station may maintain an RRC context for the UE at least during a period of time that the UE stays in a RAN notification area of the anchor base station and/or during a period of time that the UE stays in RRC inactive 606.

[0126] A gNB, such as gNBs 160 in FIG. 1 B, may be split into two parts: a central unit (gNB-CU), and one or more distributed units (gNB-DU). A gNB-CU may be coupled to one or more gNB-DUs using an F1 interface. The gNB-CU may comprise the RRC, the PDCP, and the SDAP. A gNB-DU may comprise the RLC, the MAC, and the PHY.

[0127] In NR, the physical signals and physical channels (discussed with respect to FIG. 5A and FIG. 5B) may be mapped onto orthogonal frequency divisional multiplexing (OFDM) symbols. OFDM is a multicarrier communication scheme that transmits data over F orthogonal subcarriers (or tones). Before transmission, the data may be mapped to a series of complex symbols (e.g., M-quadrature amplitude modulation (M-QAM) or M-phase shift keying (M-PSK) symbols), referred to as source symbols, and divided into F parallel symbol streams. The F parallel symbol streams may be treated as though they are in the frequency domain and used as inputs to an Inverse Fast Fourier Transform (IFFT) block that transforms them into the time domain. The IFFT block may take in F source symbols at a time, one from each of the F parallel symbol streams, and use each source symbol to modulate the amplitude and phase of one of F sinusoidal basis functions that correspond to the F orthogonal subcarriers. The output of the IFFT block may be F time-domain samples that represent the summation of the F orthogonal subcarriers. The F time-domain samples may form a single OFDM symbol. After some processing (e.g., addition of a cyclic prefix) and up-conversion, an OFDM symbol provided by the IFFT block may be transmitted over the air interface on a carrier frequency. The F parallel symbol streams may be mixed using an FFT block before being processed by the IFFT block. This operation produces Discrete Fourier Transform (DFT)-precoded OFDM symbols and may be used by UEs in the uplink to reduce the peak to average power ratio (PAPR). Inverse processing may be performed on the OFDM symbol at a receiver using an FFT block to recover the data mapped to the source symbols.

[0128] FIG. 7 illustrates an example configuration of an NR frame into which OFDM symbols are grouped. An NR frame may be identified by a system frame number (SFN). The SFN may repeat with a period of 1024 frames. As illustrated, one NR frame may be 10 milliseconds (ms) in duration and may include 10 subframes that are 1 ms in duration. A subframe may be divided into slots that include, for example, 14 OFDM symbols per slot.

[0129] The duration of a slot may depend on the numerology used for the OFDM symbols of the slot. In NR, a flexible numerology is supported to accommodate different cell deployments (e.g., cells with carrier frequencies below 1 GHz up to cells with carrier frequencies in the mm-wave range). A numerology may be defined in terms of subcarrier spacing and cyclic prefix duration. For a numerology in NR, subcarrier spacings may be scaled up by powers of two from a baseline subcarrier spacing of 15 kHz, and cyclic prefix durations may be scaled down by powers of two from a baseline cyclic prefix duration of 4.7 ps. For example, NR defines numerologies with the following subcarrier spacing/cyclic prefix duration combinations: 15 kHz/4.7 ps; 30 kHz/2.3 ps; 60 kHz/1.2 ps; 120 kHz/0.59 ps; and 240 kHz/0.29 ps.

[0130] A slot may have a fixed number of OFDM symbols (e.g., 14 OFDM symbols). A numerology with a higher subcarrier spacing has a shorter slot duration and, correspondingly, more slots per subframe. FIG. 7 illustrates this numerology-dependent slot duration and slots-per-subframe transmission structure (the numerology with a subcarrier spacing of 240 kHz is not shown in FIG. 7 for ease of illustration). A subframe in NR may be used as a numerologyindependent time reference, while a slot may be used as the unit upon which uplink and downlink transmissions are scheduled. To support low latency, scheduling in NR may be decoupled from the slot duration and start at any OFDM symbol and last for as many symbols as needed for a transmission. These partial slot transmissions may be referred to as mini-slot or subslot transmissions.

[0131] FIG. 8 illustrates an example configuration of a slot in the time and frequency domain for an NR carrier. The slot includes resource elements (REs) and resource blocks (RBs). An RE is the smallest physical resource in NR. An RE spans one OFDM symbol in the time domain by one subcarrier in the frequency domain as shown in FIG. 8. An RB spans twelve consecutive REs in the frequency domain as shown in FIG. 8. An NR carrier may be limited to a width of 275 RBs or 275x12 = 3300 subcarriers. Such a limitation, if used, may limit the NR carrier to 50, 100, 200, and 400 MHz for subcarrier spacings of 15, 30, 60, and 120 kHz, respectively, where the 400 MHz bandwidth may be set based on a 400 MHz per carrier bandwidth limit.

[0132] FIG. 8 illustrates a single numerology being used across the entire bandwidth of the NR carrier. In other example configurations, multiple numerologies may be supported on the same carrier.

[0133] NR may support wide carrier bandwidths (e.g., up to 400 MHz for a subcarrier spacing of 120 kHz). Not all UEs may be able to receive the full carrier bandwidth (e.g., due to hardware limitations). Also, receiving the full carrier bandwidth may be prohibitive in terms of UE power consumption. In an example, to reduce power consumption and/or for other purposes, a UE may adapt the size of the UE’s receive bandwidth based on the amount of traffic the UE is scheduled to receive. This is referred to as bandwidth adaptation.

[0134] NR defines bandwidth parts (BWPs) to support UEs not capable of receiving the full carrier bandwidth and to support bandwidth adaptation. In an example, a BMP may be defined by a subset of contiguous RBs on a carrier. A UE may be configured (e.g. , via RRC layer) with one or more downlink BWPs and one or more uplink BWPs per serving cell (e.g., up to four downlink BWPs and up to four uplink BWPs per serving cell). At a given time, one or more of the configured BWPs for a serving cell may be active. These one or more BWPs may be referred to as active BWPs of the serving cell. When a serving cell is configured with a secondary uplink carrier, the serving cell may have one or more first active BWPs in the uplink carrier and one or more second active BWPs in the secondary uplink carrier.

[0135] For unpaired spectra, a downlink BWP from a set of configured downlink BWPs may be linked with an uplink BWP from a set of configured uplink BWPs if a downlink BWP index of the downlink BWP and an uplink BWP index of the uplink BWP are the same. For unpaired spectra, a UE may expect that a center frequency for a downlink BWP is the same as a center frequency for an uplink BWP.

[0136] For a downlink BWP in a set of configured downlink BWPs on a primary cell (PCell), a base station may configure a UE with one or more control resource sets (CORESETs) for at least one search space. A search space is a set of locations in the time and frequency domains where the UE may find control information. The search space may be a UE-specific search space or a common search space (potentially usable by a plurality of UEs). For example, a base station may configure a UE with a common search space, on a PCell or on a primary secondary cell (PSCell), in an active downlink BWP.

[0137] For an uplink BWP in a set of configured uplink BWPs, a BS may configure a UE with one or more resource sets for one or more PUCCH transmissions. A UE may receive downlink receptions (e.g., PDCCH or PDSCH) in a downlink BWP according to a configured numerology (e.g., subcarrier spacing and cyclic prefix duration) for the downlink BWP. The UE may transmit uplink transmissions (e.g., PUCCH or PUSCH) in an uplink BWP according to a configured numerology (e.g., subcarrier spacing and cyclic prefix length for the uplink BWP).

[0138] One or more BWP indicator fields may be provided in Downlink Control Information (DCI). A value of a BWP indicator field may indicate which BWP in a set of configured BWPs is an active downlink BWP for one or more downlink receptions. The value of the one or more BWP indicator fields may indicate an active uplink BWP for one or more uplink transmissions.

[0139] A base station may sem i-statically configure a UE with a default downlink BWP within a set of configured downlink BWPs associated with a PCell. If the base station does not provide the default downlink BWP to the UE, the default downlink BWP may be an initial active downlink BWP. The UE may determine which BWP is the initial active downlink BWP based on a CORESET configuration obtained using the PBCH.

[0140] A base station may configure a UE with a BWP inactivity timer value for a PCell. The UE may start or restart a BWP inactivity timer at any appropriate time. For example, the UE may start or restart the BWP inactivity timer (a) when the UE detects a DCI indicating an active downlink BWP other than a default downlink BWP for a paired spectra operation; or (b) when a UE detects a DCI indicating an active downlink BWP or active uplink BWP other than a default downlink BWP or uplink BWP for an unpaired spectra operation. If the UE does not detect DCI during an interval of time (e.g., 1 ms or 0.5 ms), the UE may run the BWP inactivity timer toward expiration (for example, increment from zero to the BWP inactivity timer value, or decrement from the BWP inactivity timer value to zero). When the BWP inactivity timer expires, the UE may switch from the active downlink BWP to the default downlink BWP.

[0141] In an example, a base station may semi-statically configure a UE with one or more BWPs. A UE may switch an active BWP from a first BWP to a second BWP in response to receiving a DOI indicating the second BWP as an active BWP and/or in response to an expiry of the BWP inactivity timer (e.g., if the second BWP is the default BWP). [0142] Downlink and uplink BWP switching (where BWP switching refers to switching from a currently active BWP to a not currently active BWP) may be performed independently in paired spectra. In unpaired spectra, downlink and uplink BWP switching may be performed simultaneously. Switching between configured BWPs may occur based on RRC signaling, DOI, expiration of a BWP inactivity timer, and/or an initiation of random access.

[0143] FIG. 9 illustrates an example of bandwidth adaptation using three configured BWPs for an NR carrier. A UE configured with the three BWPs may switch from one BWP to another BWP at a switching point. In the example illustrated in FIG. 9, the BWPs include: a BWP 902 with a bandwidth of 40 MHz and a subcarrier spacing of 15 kHz; a BWP 904 with a bandwidth of 10 MHz and a subcarrier spacing of 15 kHz; and a BWP 906 with a bandwidth of 20 MHz and a subcarrier spacing of 60 kHz. The BWP 902 may be an initial active BWP, and the BWP 904 may be a default BWP. The UE may switch between BWPs at switching points. In the example of FIG. 9, the UE may switch from the BWP 902 to the BWP 904 at a switching point 908. The switching at the switching point 908 may occur for any suitable reason, for example, in response to an expiry of a BWP inactivity timer (indicating switching to the default BWP) and/or in response to receiving a DOI indicating BWP 904 as the active BWP. The UE may switch at a switching point 910 from active BWP 904 to BWP 906 in response to receiving a DOI indicating BWP 906 as the active BWP. The UE may switch at a switching point 912 from active BWP 906 to BWP 904 in response to an expiry of a BWP inactivity timer and/or in response to receiving a DOI indicating BWP 904 as the active BWP. The UE may switch at a switching point 914 from active BWP 904 to BWP 902 in response to receiving a DOI indicating BWP 902 as the active BWP.

[0144] If a UE is configured for a secondary cell with a default downlink BWP in a set of configured downlink BWPs and a timer value, UE procedures for switching BWPs on a secondary cell may be the same/similar as those on a primary cell. For example, the UE may use the timer value and the default downlink BWP for the secondary cell in the same/similar manner as the UE would use these values for a primary cell.

[0145] To provide for greater data rates, two or more carriers can be aggregated and simultaneously transmitted to/from the same UE using carrier aggregation (GA). The aggregated carriers in GA may be referred to as component carriers (00s). When GA is used, there are a number of serving cells for the UE, one for a CO. The 00s may have three configurations in the frequency domain.

[0146] FIG. 10A illustrates the three GA configurations with two 00s. In the intraband, contiguous configuration 1002, the two 00s are aggregated in the same frequency band (frequency band A) and are located directly adjacent to each other within the frequency band. In the intraband, non-contiguous configuration 1004, the two 00s are aggregated in the same frequency band (frequency band A) and are separated in the frequency band by a gap. In the interband configuration 1006, the two CCs are located in frequency bands (frequency band A and frequency band B).

[0147] In an example, up to 32 CCs may be aggregated. The aggregated CCs may have the same or different bandwidths, subcarrier spacing, and/or duplexing schemes (TDD or FDD). A serving cell for a UE using CA may have a downlink CC. For FDD, one or more uplink CCs may be optionally configured for a serving cell. The ability to aggregate more downlink carriers than uplink carriers may be useful, for example, when the UE has more data traffic in the downlink than in the uplink.

[0148] When CA is used, one of the aggregated cells for a UE may be referred to as a primary cell (PCell). The PCell may be the serving cell that the UE initially connects to at RRC connection establishment, reestablishment, and/or handover. The PCell may provide the UE with NAS mobility information and the security input. UEs may have different PCells. In the downlink, the carrier corresponding to the PCell may be referred to as the downlink primary CC (DL PCC). In the uplink, the carrier corresponding to the PCell may be referred to as the uplink primary CC (UL PCC). The other aggregated cells for the UE may be referred to as secondary cells (SCells). In an example, the SCells may be configured after the PCell is configured for the UE. For example, an SCell may be configured through an RRC Connection Reconfiguration procedure. In the downlink, the carrier corresponding to an SCell may be referred to as a downlink secondary CC (DL SCC). In the uplink, the carrier corresponding to the SCell may be referred to as the uplink secondary CC (UL SCC).

[0149] Configured SCells for a UE may be activated and deactivated based on, for example, traffic and channel conditions. Deactivation of an SCell may mean that PDCCH and PDSCH reception on the SCell is stopped and PUSCH, SRS, and CQI transmissions on the SCell are stopped. Configured SCells may be activated and deactivated using a MAC CE with respect to FIG. 4B. For example, a MAC CE may use a bitmap (e.g., one bit per SCell) to indicate which SCells (e.g., in a subset of configured SCells) for the UE are activated or deactivated. Configured SCells may be deactivated in response to an expiration of an SCell deactivation timer (e.g., one SCell deactivation timer per SCell). [0150] Downlink control information, such as scheduling assignments and scheduling grants, for a cell may be transmitted on the cell corresponding to the assignments and grants, which is known as self-scheduling. The DCI for the cell may be transmitted on another cell, which is known as cross-carrier scheduling. Uplink control information (e.g., HARQ acknowledgments and channel state feedback, such as CQI, PMI, and/or Rl) for aggregated cells may be transmitted on the PUCCH of the PCell. For a larger number of aggregated downlink CCs, the PUCCH of the PCell may become overloaded. Cells may be divided into multiple PUCCH groups.

[0151] FIG. 10B illustrates an example of how aggregated cells may be configured into one or more PUCCH groups. A PUCCH group 1010 and a PUCCH group 1050 may include one or more downlink CCs, respectively. In the example of FIG. 10B, the PUCCH group 1010 includes three downlink CCs: a PCell 1011, an SCell 1012, and an SCell 1013. The PUCCH group 1050 includes three downlink CCs in the present example: a PCell 1051, an SCell 1052, and an SCell 1053. One or more uplink CCs may be configured as a PCell 1021, an SCell 1022, and an SCell 1023. One or more other uplink CCs may be configured as a primary SCell (PSCell) 1061, an SCell 1062, and an SCell 1063. Uplink control information (UCI) related to the downlink CCs of the PUCCH group 1010, shown as UC1 1031, UC1 1032, and UC1 1033, may be transmitted in the uplink of the PCell 1021. Uplink control information (UCI) related to the downlink CCs of the PUCCH group 1050, shown as UC1 1071, UC1 1072, and UC1 1073, may be transmitted in the uplink of the PSCell 1061. In an example, if the aggregated cells depicted in FIG. 10B were not divided into the PUCCH group 1010 and the PUCCH group 1050, a single uplink PCell to transmit UCI relating to the downlink CCs, and the PCell may become overloaded. By dividing transmissions of UCI between the PCell 1021 and the PSCell 1061, overloading may be prevented.

[0152] A cell, comprising a downlink carrier and optionally an uplink carrier, may be assigned with a physical cell ID and a cell index. The physical cell ID or the cell index may identify a downlink carrier and/or an uplink carrier of the cell, for example, depending on the context in which the physical cell ID is used. A physical cell ID may be determined using a synchronization signal transmitted on a downlink component carrier. A cell index may be determined using RRC messages. In the disclosure, a physical cell ID may be referred to as a carrier ID, and a cell index may be referred to as a carrier index. For example, when the disclosure refers to a first physical cell ID for a first downlink carrier, the disclosure may mean the first physical cell ID is for a cell comprising the first downlink carrier. The same/similar concept may apply to, for example, a carrier activation. When the disclosure indicates that a first carrier is activated, the specification may mean that a cell comprising the first carrier is activated.

[0153] In GA, a multi-carrier nature of a PHY may be exposed to a MAC. In an example, a HARQ entity may operate on a serving cell. A transport block may be generated per assignment/grant per serving cell. A transport block and potential HARQ retransmissions of the transport block may be mapped to a serving cell.

[0154] In the downlink, a base station may transmit (e.g., unicast, multicast, and/or broadcast) one or more Reference Signals (RSs) to a UE (e.g., PSS, SSS, CSI-RS, DMRS, and/or PT-RS, as shown in FIG. 5A). In the uplink, the UE may transmit one or more RSs to the base station (e.g., DMRS, PT-RS, and/or SRS, as shown in FIG. 5B). The PSS and the SSS may be transmitted by the base station and used by the UE to synchronize the UE to the base station. The PSS and the SSS may be provided in a synchronization signal (SS) I physical broadcast channel (PBCH) block that includes the PSS, the SSS, and the PBCH. The base station may periodically transmit a burst of SS/PBCH blocks.

[0155] FIG. 11A illustrates an example of an SS/PBCH block's structure and location. A burst of SS/PBCH blocks may include one or more SS/PBCH blocks (e.g., 4 SS/PBCH blocks, as shown in FIG. 11A). Bursts may be transmitted periodically (e.g., every 2 frames or 20 ms). A burst may be restricted to a half-frame (e.g., a first half-frame having a duration of 5 ms). It will be understood that FIG. 11A is an example, and that these parameters (number of SS/PBCH blocks per burst, periodicity of bursts, position of burst within the frame) may be configured based on, for example: a carrier frequency of a cell in which the SS/PBCH block is transmitted; a numerology or subcarrier spacing of the cell; a configuration by the network (e.g., using RRC signaling); or any other suitable factor. In an example, the UE may assume a subcarrier spacing for the SS/PBCH block based on the carrier frequency being monitored, unless the radio network configured the UE to assume a different subcarrier spacing.

[0156] The SS/PBCH block may span one or more OFDM symbols in the time domain (e.g., 4 OFDM symbols, as shown in the example of FIG. 11A) and may span one or more subcarriers in the frequency domain (e.g., 240 contiguous subcarriers). The PSS, the SSS, and the PBCH may have a common center frequency. The PSS may be transmitted first and may span, for example, 1 OFDM symbol and 127 subcarriers. The SSS may be transmitted after the PSS (e.g., two symbols later) and may span 1 OFDM symbol and 127 subcarriers. The PBCH may be transmitted after the PSS (e.g., across the next 3 OFDM symbols) and may span 240 subcarriers.

[0157] The location of the SS/PBCH block in the time and frequency domains may not be known to the UE (e.g., if the UE is searching for the cell). To find and select the cell, the UE may monitor a carrier for the PSS. For example, the UE may monitor a frequency location within the carrier. If the PSS is not found after a certain duration (e.g., 20 ms), the UE may search for the PSS at a different frequency location within the carrier, as indicated by a synchronization raster. If the PSS is found at a location in the time and frequency domains, the UE may determine, based on a known structure of the SS/PBCH block, the locations of the SSS and the PBCH, respectively. The SS/PBCH block may be a celldefining SS block (CD-SSB). In an example, a primary cell may be associated with a CD-SSB. The CD-SSB may be located on a synchronization raster. In an example, a cell selection/search and/or reselection may be based on the CD- SSB.

[0158] The SS/PBCH block may be used by the UE to determine one or more parameters of the cell. For example, the UE may determine a physical cell identifier (PCI) of the cell based on the sequences of the PSS and the SSS, respectively. The UE may determine a location of a frame boundary of the cell based on the location of the SS/PBCH block. For example, the SS/PBCH block may indicate that it has been transmitted in accordance with a transmission pattern, wherein a SS/PBCH block in the transmission pattern is a known distance from the frame boundary.

[0159] The PBCH may use a QPSK modulation and may use forward error correction (FEC). The FEC may use polar coding. One or more symbols spanned by the PBCH may carry one or more DMRSs for demodulation of the PBCH. The PBCH may include an indication of a current system frame number (SFN) of the cell and/or a SS/PBCH block timing index. These parameters may facilitate time synchronization of the UE to the base station. The PBCH may include a master information block (MIB) used to provide the UE with one or more parameters. The MIB may be used by the UE to locate remaining minimum system information (RMSI) associated with the cell. The RMSI may include a System Information Block Type 1 (SIB1). The SIB1 may contain information needed by the UE to access the cell. The UE may use one or more parameters of the MIB to monitor PDCCH, which may be used to schedule PDSCH. The PDSCH may include the SIB1. The SIB1 may be decoded using parameters provided in the MIB. The PBCH may indicate an absence of SIB1. Based on the PBCH indicating the absence of SIB1 , the UE may be pointed to a frequency. The UE may search for an SS/PBCH block at the frequency to which the UE is pointed. [0160] The UE may assume that one or more SS/PBCH blocks transmitted with a same SS/PBCH block index are quasi co-located (QCLed) (e.g. , having the same/similar Doppler spread, Doppler shift, average gain, average delay, and/or spatial Rx parameters). The UE may not assume QCL for SS/PBCH block transmissions having different SS/PBCH block indices.

[0161] SS/PBCH blocks (e.g., those within a half-frame) may be transmitted in spatial directions (e.g., using different beams that span a coverage area of the cell). In an example, a first SS/PBCH block may be transmitted in a first spatial direction using a first beam, and a second SS/PBCH block may be transmitted in a second spatial direction using a second beam.

[0162] In an example, within a frequency span of a carrier, a base station may transmit a plurality of SS/PBCH blocks. In an example, a first PCI of a first SS/PBCH block of the plurality of SS/PBCH blocks may be different from a second PCI of a second SS/PBCH block of the plurality of SS/PBCH blocks. The PCIs of SS/PBCH blocks transmitted in different frequency locations may be different or the same.

[0163] The CSI-RS may be transmitted by the base station and used by the UE to acquire channel state information (CSI). The base station may configure the UE with one or more CSI-RSs for channel estimation or any other suitable purpose. The base station may configure a UE with one or more of the same/similar CSI-RSs. The UE may measure the one or more CSI-RSs. The UE may estimate a downlink channel state and/or generate a CSI report based on the measuring of the one or more downlink CSI-RSs. The UE may provide the CSI report to the base station. The base station may use feedback provided by the UE (e.g., the estimated downlink channel state) to perform link adaptation. [0164] The base station may semi-statically configure the UE with one or more CSI-RS resource sets. A CSI-RS resource may be associated with a location in the time and frequency domains and a periodicity. The base station may selectively activate and/or deactivate a CSI-RS resource. The base station may indicate to the UE that a CSI-RS resource in the CSI-RS resource set is activated and/or deactivated.

[0165] The base station may configure the UE to report CSI measurements. The base station may configure the UE to provide CSI reports periodically, aperiodically, or semi-persistently. For periodic CSI reporting, the UE may be configured with a timing and/or periodicity of a plurality of CSI reports. For aperiodic CSI reporting, the base station may request a CSI report. For example, the base station may command the UE to measure a configured CSI-RS resource and provide a CSI report relating to the measurements. For semi-persistent CSI reporting, the base station may configure the UE to transmit periodically, and selectively activate or deactivate the periodic reporting. The base station may configure the UE with a CSI-RS resource set and CSI reports using RRC signaling.

[0166] The CSI-RS configuration may comprise one or more parameters indicating, for example, up to 32 antenna ports. The UE may be configured to employ the same OFDM symbols for a downlink CSI-RS and a control resource set (CORESET) when the downlink CSI-RS and CORESET are spatially QCLed and resource elements associated with the downlink CSI-RS are outside of the physical resource blocks (PRBs) configured for the CORESET. The UE may be configured to employ the same OFDM symbols for downlink CSI-RS and SS/PBCH blocks when the downlink CSI-RS and SS/PBCH blocks are spatially QCLed and resource elements associated with the downlink CSI-RS are outside of PRBs configured for the SS/PBCH blocks.

[0167] Downlink DMRSs may be transmitted by a base station and used by a UE for channel estimation. For example, the downlink DMRS may be used for coherent demodulation of one or more downlink physical channels (e.g. , PDSCH). An NR network may support one or more variable and/or configurable DMRS patterns for data demodulation. At least one downlink DMRS configuration may support a front-loaded DMRS pattern. A front-loaded DMRS may be mapped over one or more OFDM symbols (e.g., one or two adjacent OFDM symbols). A base station may semi- statically configure the UE with a number (e.g. a maximum number) of front-loaded DMRS symbols for PDSCH. A DMRS configuration may support one or more DMRS ports. For example, for single user-MIMO, a DMRS configuration may support up to eight orthogonal downlink DMRS ports per UE. For multiuser-MI MO, a DMRS configuration may support up to 4 orthogonal downlink DMRS ports per UE. A radio network may support (e.g., at least for CP-OFDM) a common DMRS structure for downlink and uplink, wherein a DMRS location, a DMRS pattern, and/or a scrambling sequence may be the same or different. The base station may transmit a downlink DMRS and a corresponding PDSCH using the same precoding matrix. The UE may use the one or more downlink DMRSs for coherent demodulation/channel estimation of the PDSCH.

[0168] In an example, a transmitter (e.g., a base station) may use a precoder matrices for a part of a transmission bandwidth. For example, the transmitter may use a first precoder matrix for a first bandwidth and a second precoder matrix for a second bandwidth. The first precoder matrix and the second precoder matrix may be different based on the first bandwidth being different from the second bandwidth. The UE may assume that a same precoding matrix is used across a set of PRBs. The set of PRBs may be denoted as a precoding resource block group (PRG).

[0169] A PDSCH may comprise one or more layers. The UE may assume that at least one symbol with DMRS is present on a layer of the one or more layers of the PDSCH. A higher layer may configure up to 3 DMRSs for the PDSCH.

[0170] Downlink PT-RS may be transmitted by a base station and used by a UE for phase-noise compensation. Whether a downlink PT-RS is present or not may depend on an RRC configuration. The presence and/or pattern of the downlink PT-RS may be configured on a UE-specific basis using a combination of RRC signaling and/or an association with one or more parameters employed for other purposes (e.g., modulation and coding scheme (MCS)), which may be indicated by DCI. When configured, a dynamic presence of a downlink PT-RS may be associated with one or more DCI parameters comprising at least MCS. An NR network may support a plurality of PT-RS densities defined in the time and/or frequency domains. When present, a frequency domain density may be associated with at least one configuration of a scheduled bandwidth. The UE may assume a same precoding for a DMRS port and a PT-RS port. A number of PT-RS ports may be fewer than a number of DMRS ports in a scheduled resource. Downlink PT-RS may be confined in the scheduled time/frequency duration for the UE. Downlink PT-RS may be transmitted on symbols to facilitate phase tracking at the receiver. [0171] The UE may transmit an uplink DMRS to a base station for channel estimation. For example, the base station may use the uplink DMRS for coherent demodulation of one or more uplink physical channels. For example, the UE may transmit an uplink DMRS with a PUSCH and/or a PUCCH. The uplink DM-RS may span a range of frequencies that is similar to a range of frequencies associated with the corresponding physical channel. The base station may configure the UE with one or more uplink DMRS configurations. At least one DMRS configuration may support a front- loaded DMRS pattern. The front-loaded DMRS may be mapped over one or more OFDM symbols (e.g., one or two adjacent OFDM symbols). One or more uplink DMRSs may be configured to transmit at one or more symbols of a PUSCH and/or a PUCCH. The base station may semi-statically configure the UE with a number (e.g. maximum number) of front-loaded DMRS symbols for the PUSCH and/or the PUCCH, which the UE may use to schedule a single-symbol DMRS and/or a double-symbol DMRS. An NR network may support (e.g., for cyclic prefix orthogonal frequency division multiplexing (CP-OFDM)) a common DMRS structure for downlink and uplink, wherein a DMRS location, a DMRS pattern, and/or a scrambling sequence for the DMRS may be the same or different.

[0172] A PUSCH may comprise one or more layers, and the UE may transmit at least one symbol with DMRS present on a layer of the one or more layers of the PUSCH. In an example, a higher layer may configure up to three DMRSs for the PUSCH.

[0173] Uplink PT-RS (which may be used by a base station for phase tracking and/or phase-noise compensation) may or may not be present depending on an RRC configuration of the UE. The presence and/or pattern of uplink PT- RS may be configured on a UE-specific basis by a combination of RRC signaling and/or one or more parameters employed for other purposes (e.g., Modulation and Coding Scheme (MCS)), which may be indicated by DCI. When configured, a dynamic presence of uplink PT-RS may be associated with one or more DCI parameters comprising at least MCS. A radio network may support a plurality of uplink PT-RS densities defined in time/frequency domain. When present, a frequency domain density may be associated with at least one configuration of a scheduled bandwidth. The UE may assume a same precoding for a DMRS port and a PT-RS port. A number of PT-RS ports may be fewer than a number of DMRS ports in a scheduled resource. For example, uplink PT-RS may be confined in the scheduled time/frequency duration for the UE.

[0174] SRS may be transmitted by a UE to a base station for channel state estimation to support uplink channel dependent scheduling and/or link adaptation. SRS transmitted by the UE may allow a base station to estimate an uplink channel state at one or more frequencies. A scheduler at the base station may employ the estimated uplink channel state to assign one or more resource blocks for an uplink PUSCH transmission from the UE. The base station may semi-statically configure the UE with one or more SRS resource sets. For an SRS resource set, the base station may configure the UE with one or more SRS resources. An SRS resource set applicability may be configured by a higher layer (e.g., RRC) parameter. For example, when a higher layer parameter indicates beam management, an SRS resource in an SRS resource set of the one or more SRS resource sets (e.g., with the same/similar time domain behavior, periodic, aperiodic, and/or the like) may be transmitted at a time instant (e.g., simultaneously). The UE may transmit one or more SRS resources in SRS resource sets. An NR network may support aperiodic, periodic and/or semi-persistent SRS transmissions. The UE may transmit SRS resources based on one or more trigger types, wherein the one or more trigger types may comprise higher layer signaling (e.g., RRC) and/or one or more DOI formats. In an example, at least one DOI format may be employed for the UE to select at least one of one or more configured SRS resource sets. An SRS trigger type 0 may refer to an SRS triggered based on a higher layer signaling. An SRS trigger type 1 may refer to an SRS triggered based on one or more DOI formats. In an example, when PUSCH and SRS are transmitted in a same slot, the UE may be configured to transmit SRS after a transmission of a PUSCH and a corresponding uplink DMRS.

[0175] The base station may semi-statically configure the UE with one or more SRS configuration parameters indicating at least one of following: a SRS resource configuration identifier; a number of SRS ports; time domain behavior of an SRS resource configuration (e.g., an indication of periodic, semi-persistent, or aperiodic SRS); slot, minislot, and/or subframe level periodicity; offset for a periodic and/or an aperiodic SRS resource; a number of OFDM symbols in an SRS resource; a starting OFDM symbol of an SRS resource; an SRS bandwidth; a frequency hopping bandwidth; a cyclic shift; and/or an SRS sequence ID.

[0176] An antenna port is defined such that the channel over which a symbol on the antenna port is conveyed can be inferred from the channel over which another symbol on the same antenna port is conveyed. If a first symbol and a second symbol are transmitted on the same antenna port, the receiver may infer the channel (e.g., fading gain, multipath delay, and/or the like) for conveying the second symbol on the antenna port, from the channel for conveying the first symbol on the antenna port. A first antenna port and a second antenna port may be referred to as quasi colocated (QCLed) if one or more large-scale properties of the channel over which a first symbol on the first antenna port is conveyed may be inferred from the channel over which a second symbol on a second antenna port is conveyed. The one or more large-scale properties may comprise at least one of: a delay spread; a Doppler spread; a Doppler shift; an average gain; an average delay; and/or spatial Receiving (Rx) parameters.

[0177] Channels that use beamforming require beam management. Beam management may comprise beam measurement, beam selection, and beam indication. A beam may be associated with one or more reference signals. For example, a beam may be identified by one or more beamformed reference signals. The UE may perform downlink beam measurement based on downlink reference signals (e.g., a channel state information reference signal (OS l-RS)) and generate a beam measurement report. The UE may perform the downlink beam measurement procedure after an RRC connection is set up with a base station.

[0178] FIG. 11B illustrates an example of channel state information reference signals (CSI-RSs) that are mapped in the time and frequency domains. A square shown in FIG. 11 B may span a resource block (RB) within a bandwidth of a cell. A base station may transmit one or more RRC messages comprising CSI-RS resource configuration parameters indicating one or more CSI-RSs. One or more of the following parameters may be configured by higher layer signaling (e.g., RRC and/or MAC signaling) for a CSI-RS resource configuration: a CSI-RS resource configuration identity, a number of CSI-RS ports, a CSI-RS configuration (e.g. , symbol and resource element (RE) locations in a subframe), a CSI-RS subframe configuration (e.g., subframe location, offset, and periodicity in a radio frame), a CSI-RS power parameter, a CSI-RS sequence parameter, a code division multiplexing (CDM) type parameter, a frequency density, a transmission comb, quasi co-location (QCL) parameters (e.g., QCL-scramblingidentity, crs-portscount, mbsfn- subframeconfiglist, csi-rs-configZPid, qcl-csi-rs-configNZPid , and/or other radio resource parameters.

[0179] The three beams illustrated in FIG. 11 B may be configured for a UE in a UE-specific configuration. Three beams are illustrated in FIG. 11 B (beam #1 , beam #2, and beam #3), more or fewer beams may be configured. Beam #1 may be allocated with CSI-RS 1101 that may be transmitted in one or more subcarriers in an RB of a first symbol. Beam #2 may be allocated with CSI-RS 1102 that may be transmitted in one or more subcarriers in an RB of a second symbol. Beam #3 may be allocated with CSI-RS 1103 that may be transmitted in one or more subcarriers in an RB of a third symbol. By using frequency division multiplexing (FDM), a base station may use other subcarriers in a same RB (for example, those that are not used to transmit CSI-RS 1101) to transmit another CSI-RS associated with a beam for another UE. By using time domain multiplexing (TDM), beams used for the UE may be configured such that beams for the UE use symbols from beams of other UEs.

[0180] CSI-RSs such as those illustrated in FIG. 11 B (e.g., CSI-RS 1101, 1102, 1103) may be transmitted by the base station and used by the UE for one or more measurements. For example, the UE may measure a reference signal received power (RSRP) of configured CSI-RS resources. The base station may configure the UE with a reporting configuration and the UE may report the RSRP measurements to a network (for example, via one or more base stations) based on the reporting configuration. In an example, the base station may determine, based on the reported measurement results, one or more transmission configuration indication (TCI) states comprising a number of reference signals. In an example, the base station may indicate one or more TCI states to the UE (e.g., via RRC signaling, a MAC CE, and/or a DCI). The UE may receive a downlink transmission with a receive (Rx) beam determined based on the one or more TCI states. In an example, the UE may or may not have a capability of beam correspondence. If the UE has the capability of beam correspondence, the UE may determine a spatial domain filter of a transmit (Tx) beam based on a spatial domain filter of the corresponding Rx beam. If the UE does not have the capability of beam correspondence, the UE may perform an uplink beam selection procedure to determine the spatial domain filter of the Tx beam. The UE may perform the uplink beam selection procedure based on one or more sounding reference signal (SRS) resources configured to the UE by the base station. The base station may select and indicate uplink beams for the UE based on measurements of the one or more SRS resources transmitted by the UE.

[0181] In a beam management procedure, a UE may assess (e.g., measure) a channel quality of one or more beam pair links, a beam pair link comprising a transmitting beam transmitted by a base station and a receiving beam received by the UE. Based on the assessment, the UE may transmit a beam measurement report indicating one or more beam pair quality parameters comprising, e.g., one or more beam identifications (e.g., a beam index, a reference signal index, or the like), RSRP, a precoding matrix indicator (PMI), a channel quality indicator (CQI), and/or a rank indicator (Rl). [0182] FIG. 12A illustrates examples of three downlink beam management procedures: P1 , P2, and P3. Procedure P1 may enable a UE measurement on transmit (Tx) beams of a transmission reception point (TRP) (or multiple TRPs), e.g., to support a selection of one or more base station Tx beams and/or UE Rx beams (shown as ovals in the top row and bottom row, respectively, of P1). Beamforming at a TRP may comprise a Tx beam sweep for a set of beams (shown, in the top rows of P1 and P2, as ovals rotated in a counterclockwise direction indicated by the dashed arrow). Beamforming at a UE may comprise an Rx beam sweep for a set of beams (shown, in the bottom rows of P1 and P3, as ovals rotated in a clockwise direction indicated by the dashed arrow). Procedure P2 may be used to enable a UE measurement on Tx beams of a TRP (shown, in the top row of P2, as ovals rotated in a counterclockwise direction indicated by the dashed arrow). The UE and/or the base station may perform procedure P2 using a smaller set of beams than is used in procedure P1 , or using narrower beams than the beams used in procedure P1. This may be referred to as beam refinement. The UE may perform procedure P3 for Rx beam determination by using the same Tx beam at the base station and sweeping an Rx beam at the UE.

[0183] FIG. 12B illustrates examples of three uplink beam management procedures: U1, U2, and U3. Procedure U1 may be used to enable a base station to perform a measurement on Tx beams of a UE, e.g., to support a selection of one or more UE Tx beams and/or base station Rx beams (shown as ovals in the top row and bottom row, respectively, of U1). Beamforming at the UE may include, e.g., a Tx beam sweep from a set of beams (shown in the bottom rows of U1 and U3 as ovals rotated in a clockwise direction indicated by the dashed arrow). Beamforming at the base station may include, e.g., an Rx beam sweep from a set of beams (shown, in the top rows of U1 and U2, as ovals rotated in a counterclockwise direction indicated by the dashed arrow). Procedure U2 may be used to enable the base station to adjust its Rx beam when the UE uses a fixed Tx beam. The UE and/or the base station may perform procedure U2 using a smaller set of beams than is used in procedure P1, or using narrower beams than the beams used in procedure P1. This may be referred to as beam refinement The UE may perform procedure U3 to adjust its Tx beam when the base station uses a fixed Rx beam.

[0184] A UE may initiate a beam failure recovery (BFR) procedure based on detecting a beam failure. The UE may transmit a BFR request (e.g., a preamble, a UCI, an SR, a MAC CE, and/or the like) based on the initiating of the BFR procedure. The UE may detect the beam failure based on a determination that a quality of beam pair link(s) of an associated control channel is unsatisfactory (e.g., having an error rate higher than an error rate threshold, a received signal power lower than a received signal power threshold, an expiration of a timer, and/or the like).

[0185] The UE may measure a quality of a beam pair link using one or more reference signals (RSs) comprising one or more SS/PBCH blocks, one or more CSI-RS resources, and/or one or more demodulation reference signals (DMRSs). A quality of the beam pair link may be based on one or more of a block error rate (BLER), an RSRP value, a signal to interference plus noise ratio (SINR) value, a reference signal received quality (RSRQ) value, and/or a CSI value measured on RS resources. The base station may indicate that an RS resource is quasi co-located (QCLed) with one or more DM-RSs of a channel (e.g., a control channel, a shared data channel, and/or the like). The RS resource and the one or more DMRSs of the channel may be QCLed when the channel characteristics (e.g., Doppler shift, Doppler spread, average delay, delay spread, spatial Rx parameter, fading, and/or the like) from a transmission via the RS resource to the UE are similar or the same as the channel characteristics from a transmission via the channel to the UE.

[0186] A network (e.g., a gNB and/or an ng-eNB of a network) and/or the UE may initiate a random access procedure. A UE in an RRC_I DLE state and/or an RRC_I NACTI VE state may initiate the random access procedure to request a connection setup to a network. The UE may initiate the random access procedure from an RRC_CONNECTED state. The UE may initiate the random access procedure to request uplink resources (e.g., for uplink transmission of an SR when there is no PUCOH resource available) and/or acquire uplink timing (e.g., when uplink synchronization status is non-synchronized). The UE may initiate the random access procedure to request one or more system information blocks (SIBs) (e.g., other system information such as SIB2, SIB3, and/or the like). The UE may initiate the random access procedure for a beam failure recovery request. A network may initiate a random access procedure for a handover and/or for establishing time alignment for an SCell addition.

[0187] FIG. 13A illustrates a four-step contention-based random access procedure. Prior to initiation of the procedure, a base station may transmit a configuration message 1310 to the UE. The procedure illustrated in FIG. 13A comprises transmission of four messages: a Msg 1 1311, a Msg 2 1312, a Msg 31313, and a Msg 41314. The Msg 1 1311 may include and/or be referred to as a preamble (or a random access preamble). The Msg 2 1312 may include and/or be referred to as a random access response (RAR).

[0188] The configuration message 1310 may be transmitted, for example, using one or more RRC messages. The one or more RRC messages may indicate one or more random access channel (RACH) parameters to the UE. The one or more RACH parameters may comprise at least one of following: general parameters for one or more random access procedures (e.g., RACH-configGeneral}; cell-specific parameters (e.g., RACH-ConfigCommon'); and/or dedicated parameters (e.g., RACH-configDedicated}. The base station may broadcast or multicast the one or more RRC messages to one or more UEs. The one or more RRC messages may be UE-specific (e.g., dedicated RRC messages transmitted to a UE in an RRC_CONNECTED state and/or in an RRCJNACTIVE state). The UE may determine, based on the one or more RACH parameters, a time-frequency resource and/or an uplink transmit power for transmission of the Msg 1 1311 and/or the Msg 31313. Based on the one or more RACH parameters, the UE may determine a reception timing and a downlink channel for receiving the Msg 2 1312 and the Msg 41314.

[0189] The one or more RACH parameters provided in the configuration message 1310 may indicate one or more Physical RACH (PRACH) occasions available for transmission of the Msg 1 1311. The one or more PRACH occasions may be predefined. The one or more RACH parameters may indicate one or more available sets of one or more PRACH occasions (e.g., prach-Configlndex). The one or more RACH parameters may indicate an association between (a) one or more PRACH occasions and (b) one or more reference signals. The one or more RACH parameters may indicate an association between (a) one or more preambles and (b) one or more reference signals. The one or more reference signals may be SS/PBCH blocks and/or CSI-RSs. For example, the one or more RACH parameters may indicate a number of SS/PBCH blocks mapped to a PRACH occasion and/or a number of preambles mapped to a SS/PBCH blocks.

[0190] The one or more RACH parameters provided in the configuration message 1310 may be used to determine an uplink transmit power of Msg 1 1311 and/or Msg 3 1313. For example, the one or more RACH parameters may indicate a reference power for a preamble transmission (e.g., a received target power and/or an initial power of the preamble transmission). There may be one or more power offsets indicated by the one or more RACH parameters. For example, the one or more RACH parameters may indicate: a power ramping step; a power offset between SSB and CSI-RS; a power offset between transmissions of the Msg 1 1311 and the Msg 3 1313; and/or a power offset value between preamble groups. The one or more RACH parameters may indicate one or more thresholds based on which the UE may determine at least one reference signal (e.g., an SSB and/or CSI-RS) and/or an uplink carrier (e.g., a normal uplink (NUL) carrier and/or a supplemental uplink (SUL) carrier).

[0191] The Msg 1 1311 may include one or more preamble transmissions (e.g., a preamble transmission and one or more preamble retransmissions). An RRC message may be used to configure one or more preamble groups (e.g., group A and/or group B). A preamble group may comprise one or more preambles. The UE may determine the preamble group based on a pathloss measurement and/or a size of the Msg 3 1313. The UE may measure an RSRP of one or more reference signals (e.g., SSBs and/or CSI-RSs) and determine at least one reference signal having an RSRP above an RSRP threshold (e.g., rsrp-ThresholdSSB and/or rsrp-ThresholdCSI-RS). The UE may select at least one preamble associated with the one or more reference signals and/or a selected preamble group, for example, if the association between the one or more preambles and the at least one reference signal is configured by an RRC message.

[0192] The UE may determine the preamble based on the one or more RACH parameters provided in the configuration message 1310. For example, the UE may determine the preamble based on a pathloss measurement, an RSRP measurement, and/or a size of the Msg 3 1313. As another example, the one or more RACH parameters may indicate: a preamble format; a maximum number of preamble transmissions; and/or one or more thresholds for determining one or more preamble groups (e.g., group A and group B). A base station may use the one or more RACH parameters to configure the UE with an association between one or more preambles and one or more reference signals (e.g., SSBs and/or CSI-RSs). If the association is configured, the UE may determine the preamble to include in Msg 1 1311 based on the association. The Msg 1 1311 may be transmitted to the base station via one or more PRACH occasions. The UE may use one or more reference signals (e.g., SSBs and/or CSI-RSs) for selection of the preamble and for determining of the PRACH occasion. One or more RACH parameters (e.g., ra-ssb-OccasionMsklndex and/or ra-OccasionList) may indicate an association between the PRACH occasions and the one or more reference signals. [0193] The UE may perform a preamble retransmission if no response is received following a preamble transmission. The UE may increase an uplink transmit power for the preamble retransmission. The UE may select an initial preamble transmit power based on a pathloss measurement and/or a target received preamble power configured by the network. The UE may determine to retransmit a preamble and may ramp up the uplink transmit power. The UE may receive one or more RACH parameters (e.g., PREAMBLE_POWER_RAMP/NG_STEP) indicating a ramping step for the preamble retransmission. The ramping step may be an amount of incremental increase in uplink transmit power for a retransmission. The UE may ramp up the uplink transmit power if the UE determines a reference signal (e.g., SSB and/or CSI-RS) that is the same as a previous preamble transmission. The UE may count a number of preamble transmissions and/or retransmissions (e.g., PREAMBLE_TRANSMISSION_COUNTER). The UE may determine that a random access procedure completed unsuccessfully, for example, if the number of preamble transmissions exceeds a threshold configured by the one or more RACH parameters (e.g., preambleTransMax).

[0194] The Msg 2 1312 received by the UE may include an RAR. In some scenarios, the Msg 21312 may include multiple RARs corresponding to multiple UEs. The Msg 2 1312 may be received after or in response to the transmitting of the Msg 1 1311. The Msg 2 1312 may be scheduled on the DL-SCH and indicated on a PDCCH using a random access RNTI (RA-RNTI). The Msg 21312 may indicate that the Msg 1 1311 was received by the base station. The Msg 2 1312 may include a time-alignment command that may be used by the UE to adjust the UE’s transmission timing, a scheduling grant for transmission of the Msg 3 1313, and/or a Temporary Cell RNTI (TC-RNTI). After transmitting a preamble, the UE may start a time window (e.g., ra-ResponseWindow) to monitor a PDCCH for the Msg 2 1312. The UE may determine when to start the time window based on a PRACH occasion that the UE uses to transmit the preamble. For example, the UE may start the time window one or more symbols after a last symbol of the preamble (e.g., at a first PDCCH occasion from an end of a preamble transmission). The one or more symbols may be determined based on a numerology. The PDCCH may be in a common search space (e.g., a Typel -PDCCH common search space) configured by an RRC message. The UE may identify the RAR based on a Radio Network Temporary Identifier (RNTI). RNTIs may be used depending on one or more events initiating the random access procedure. The UE may use random access RNTI (RA-RNTI). The RA-RNTI may be associated with PRACH occasions in which the UE transmits a preamble. For example, the UE may determine the RA-RNTI based on: an OFDM symbol index; a slot index; a frequency domain index; and/or a UL carrier indicator of the PRACH occasions. An example of RA-RNTI may be as follows:

[0195] RA-RNTI= 1 +s_id + 14 x t_id +14 x 80 x fjd + 14 x 80 x 8 x ul_carrier_id, where s_id may be an index of a first OFDM symbol of the PRACH occasion (e.g., 0 < s_id < 14), t_id may be an index of a first slot of the PRACH occasion in a system frame (e.g., 0 < t_id < 80), f_id may be an index of the PRACH occasion in the frequency domain (e.g., 0 < f_id < 8), and ul_carrier_id may be a UL carrier used for a preamble transmission (e.g., 0 for an NUL carrier, and 1 for an SUL carrier).

[0196] The UE may transmit the Msg 3 1313 in response to a successful reception of the Msg 21312 (e.g., using resources identified in the Msg 21312). The Msg 3 1313 may be used for contention resolution in, for example, the contention-based random access procedure illustrated in FIG. 13A. In some scenarios, a plurality of UEs may transmit a same preamble to a base station and the base station may provide an RAR that corresponds to a UE. Collisions may occur if the plurality of UEs interpret the RAR as corresponding to themselves. Contention resolution (e.g., using the Msg 3 1313 and the Msg 41314) may be used to increase the likelihood that the UE does not incorrectly use an identity of another the UE. To perform contention resolution, the UE may include a device identifier in the Msg 3 1313 (e.g., a C-RNTI if assigned, a TC-RNTI included in the Msg 2 1312, and/or any other suitable identifier).

[0197] The Msg 41314 may be received after or in response to the transmitting of the Msg 3 1313. If a C-RNTI was included in the Msg 3 1313, the base station will address the UE on the PDCCH using the C-RNTI. If the UE's unique C-RNTI is detected on the PDCCH, the random access procedure is determined to be successfully completed. If a TC-RNTI is included in the Msg 31313 (e.g., if the UE is in an RRC_IDLE state or not otherwise connected to the base station), Msg 41314 will be received using a DL-SCH associated with the TC-RNTI. If a MAC PDU is successfully decoded and a MAC PDU comprises the UE contention resolution identity MAC CE that matches or otherwise corresponds with the CCCH SDU sent (e.g., transmitted) in Msg 3 1313, the UE may determine that the contention resolution is successful and/or the UE may determine that the random access procedure is successfully completed. [0198] The UE may be configured with a supplementary uplink (SUL) carrier and a normal uplink (NUL) carrier. An initial access (e.g., random access procedure) may be supported in an uplink carrier. For example, a base station may configure the UE with two separate RACH configurations: one for an SUL carrier and the other for an NUL carrier. For random access in a cell configured with an SUL carrier, the network may indicate which carrier to use (NUL or SUL). The UE may determine the SUL carrier, for example, if a measured quality of one or more reference signals is lower than a broadcast threshold. Uplink transmissions of the random access procedure (e.g., the Msg 1 1311 and/or the Msg 31313) may remain on the selected carrier. The UE may switch an uplink carrier during the random access procedure (e.g., between the Msg 1 1311 and the Msg 3 1313) in one or more cases. For example, the UE may determine and/or switch an uplink carrier for the Msg 1 1311 and/or the Msg 31313 based on a channel clear assessment (e.g., a listen- before-talk).

[0199] FIG. 13B illustrates a two-step contention-free random access procedure. Similar to the four-step contentionbased random access procedure illustrated in FIG. 13A, a base station may, prior to initiation of the procedure, transmit a configuration message 1320 to the UE. The configuration message 1320 may be analogous in some respects to the configuration message 1310. The procedure illustrated in FIG. 13B comprises transmission of two messages: a Msg 1 1321 and a Msg 21322. The Msg 1 1321 and the Msg 21322 may be analogous in some respects to the Msg 1 1311 and a Msg 21312 illustrated in FIG. 13A, respectively. As will be understood from FIGS. 13A and 13B, the contention- free random access procedure may not include messages analogous to the Msg 3 1313 and/or the Msg 41314.

[0200] The contention-free random access procedure illustrated in FIG. 13B may be initiated for a beam failure recovery, other SI request, SCell addition, and/or handover. For example, a base station may indicate or assign to the UE the preamble to be used for the Msg 1 1321. The UE may receive, from the base station via PDCCH and/or RRC, an indication of a preamble (e.g., ra-Preamblelndex). [0201] After transmitting a preamble, the UE may start a time window (e.g., ra-ResponseWindow) to monitor a PDCCH for the RAR. In the event of a beam failure recovery request, the base station may configure the UE with a separate time window and/or a separate PDCCH in a search space indicated by an RRC message (e.g., recoverySearchSpaceld). The UE may monitor for a PDCCH transmission addressed to a Cell RNTI (C-RNTI) on the search space. In the contention-free random access procedure illustrated in FIG. 13B, the UE may determine that a random access procedure successfully completes after or in response to transmission of Msg 1 1321 and reception of a corresponding Msg 2 1322. The UE may determine that a random access procedure successfully completes, for example, if a PDCCH transmission is addressed to a C-RNTI. The UE may determine that a random access procedure successfully completes, for example, if the UE receives an RAR comprising a preamble identifier corresponding to a preamble transmitted by the UE and/or the RAR comprises a MAC sub-PDU with the preamble identifier. The UE may determine the response as an indication of an acknowledgement for an SI request.

[0202] FIG. 13C illustrates another two-step random access procedure. Similar to the random access procedures illustrated in FIGS. 13A and 13B, a base station may, prior to initiation of the procedure, transmit a configuration message 1330 to the UE. The configuration message 1330 may be analogous in some respects to the configuration message 1310 and/or the configuration message 1320. The procedure illustrated in FIG. 13C comprises transmission of two messages: a Msg A 1331 and a Msg B 1332.

[0203] Msg A 1331 may be transmitted in an uplink transmission by the UE. Msg A 1331 may comprise one or more transmissions of a preamble 1341 and/or one or more transmissions of a transport block 1342. The transport block 1342 may comprise contents that are similar and/or equivalent to the contents of the Msg 3 1313 illustrated in FIG. 13A. The transport block 1342 may comprise UCI (e.g., an SR, a HARQ ACK/NACK, and/or the like). The UE may receive the Msg B 1332 after or in response to transmitting the Msg A 1331. The Msg B 1332 may comprise contents that are similar and/or equivalent to the contents of the Msg 2 1312 (e.g., an RAR) illustrated in FIGS. 13A and 13B and/or the Msg 41314 illustrated in FIG. 13A.

[0204] The UE may initiate the two-step random access procedure in FIG. 130 for licensed spectrum and/or unlicensed spectrum. The UE may determine, based on one or more factors, whether to initiate the two-step random access procedure. The one or more factors may be: a radio access technology in use (e.g., LTE, NR, and/or the like); whether the UE has valid TA or not; a cell size; the UE’s RRC state; a type of spectrum (e.g., licensed vs. unlicensed); and/or any other suitable factors.

[0205] The UE may determine, based on two-step RACH parameters included in the configuration message 1330, a radio resource and/or an uplink transmit power for the preamble 1341 and/or the transport block 1342 included in the Msg A 1331. The RACH parameters may indicate a modulation and coding schemes (MCS), a time-frequency resource, and/or a power control for the preamble 1341 and/or the transport block 1342. A time-frequency resource for transmission of the preamble 1341 (e.g., a PRACH) and a time-frequency resource for transmission of the transport block 1342 (e.g., a PUSCH) may be multiplexed using FDM, TDM, and/or CDM. The RACH parameters may enable the UE to determine a reception timing and a downlink channel for monitoring for and/or receiving Msg B 1332.

[0206] The transport block 1342 may comprise data (e.g., delay-sensitive data), an identifier of the UE, security information, and/or device information (e.g., an International Mobile Subscriber Identity (I MSI)). The base station may transmit the Msg B 1332 as a response to the Msg A 1331. The Msg B 1332 may comprise at least one of following: a preamble identifier; a timing advance command; a power control command; an uplink grant (e.g., a radio resource assignment and/or an MOS); a UE identifier for contention resolution; and/or an RNTI (e.g., a C-RNTI or a TC-RNTI). The UE may determine that the two-step random access procedure is successfully completed if: a preamble identifier in the Msg B 1332 is matched to a preamble transmitted by the UE; and/or the identifier of the UE in Msg B 1332 is matched to the identifier of the UE in the Msg A 1331 (e.g., the transport block 1342).

[0207] A UE and a base station may exchange control signaling. The control signaling may be referred to as L1/L2 control signaling and may originate from the PHY layer (e.g., layer 1) and/or the MAC layer (e.g., layer 2). The control signaling may comprise downlink control signaling transmitted from the base station to the UE and/or uplink control signaling transmitted from the UE to the base station.

[0208] The downlink control signaling may comprise: a downlink scheduling assignment; an uplink scheduling grant indicating uplink radio resources and/or a transport format; a slot format information; a preemption indication; a power control command; and/or any other suitable signaling. The UE may receive the downlink control signaling in a payload transmitted by the base station on a physical downlink control channel (PDCCH). The payload transmitted on the PDCCH may be referred to as downlink control information (DOI). In some scenarios, the PDCCH may be a group common PDCCH (GC-PDCCH) that is common to a group of UEs.

[0209] A base station may attach one or more cyclic redundancy check (CRC) parity bits to a DCI in order to facilitate detection of transmission errors. When the DCI is intended for a UE (or a group of the UEs), the base station may scramble the CRC parity bits with an identifier of the UE (or an identifier of the group of the UEs). Scrambling the CRC parity bits with the identifier may comprise Modulo-2 addition (or an exclusive OR operation) of the identifier value and the CRC parity bits. The identifier may comprise a 16-bit value of a radio network temporary identifier (RNTI).

[0210] DCIs may be used for different purposes. A purpose may be indicated by the type of RNTI used to scramble the CRC parity bits. For example, a DCI having CRC parity bits scrambled with a paging RNTI (P-RNTI) may indicate paging information and/or a system information change notification. The P-RNTI may be predefined as “FFFE” in hexadecimal. A DCI having CRC parity bits scrambled with a system information RNTI (SI-RNTI) may indicate a broadcast transmission of the system information. The SI-RNTI may be predefined as “FFFF” in hexadecimal. A DCI having CRC parity bits scrambled with a random access RNTI (RA-RNTI) may indicate a random access response (RAR). A DCI having CRC parity bits scrambled with a cell RNTI (C-RNTI) may indicate a dynamically scheduled unicast transmission and/or a triggering of PDCCH-ordered random access. A DCI having CRC parity bits scrambled with a temporary cell RNTI (TC-RNTI) may indicate a contention resolution (e.g., a Msg 3 analogous to the Msg 3 1313 illustrated in FIG. 13A). Other RNTIs configured to the UE by a base station may comprise a Configured Scheduling RNT I (CS-RNTI), a Transmit Power Control-PUCOH RNTI (TPC-PUCCH-RNTI), a Transmit Power Control-PUSCH RNTI (TPC-PUSCH-RNTI), a Transmit Power Control-SRS RNTI (TPC-SRS-RNTI), an Interruption RNTI (INT-RNTI), a Slot Format Indication RNTI (SFI-RNTI), a Semi-Persistent CSI RNTI (SP-CSI-RNTI), a Modulation and Coding Scheme Cell RNTI (MCS-C-RNTI), and/or the like.

[0211] Depending on the purpose and/or content of a DCI, the base station may transmit the DCIs with one or more DCI formats. For example, DCI format 0_0 may be used for scheduling of PUSCH in a cell. DCI format 0_0 may be a fallback DCI format (e.g. , with compact DCI payloads). DCI format 0_1 may be used for scheduling of PUSCH in a cell (e.g., with more DCI payloads than DCI format 0_0). DCI format 1_0 may be used for scheduling of PDSCH in a cell. DCI format 1_0 may be a fallback DCI format (e.g., with compact DCI payloads). DCI format 1_1 may be used for scheduling of PDSCH in a cell (e.g., with more DCI payloads than DCI format 1_0). DCI format 2_0 may be used for providing a slot format indication to a group of UEs. DCI format 2_1 may be used for notifying a group of UEs of a physical resource block and/or OFDM symbol where the UE may assume no transmission is intended to the UE. DCI format 2_2 may be used for transmission of a transmit power control (TPC) command for PUCCH or PUSCH. DCI format 2_3 may be used for transmission of a group of TPC commands for SRS transmissions by one or more UEs. DCI format(s) for new functions may be defined in future releases. DCI formats may have different DCI sizes, or may share the same DCI size.

[0212] After scrambling a DCI with a RNTI, the base station may process the DCI with channel coding (e.g., polar coding), rate matching, scrambling and/or GPSK modulation. A base station may map the coded and modulated DCI on resource elements used and/or configured for a PDCCH. Based on a payload size of the DCI and/or a coverage of the base station, the base station may transmit the DCI via a PDCCH occupying a number of contiguous control channel elements (CCEs). The number of the contiguous CCEs (referred to as aggregation level) may be 1 , 2, 4, 8, 16, and/or any other suitable number. A CCE may comprise a number (e.g., 6) of resource-element groups (REGs). A REG may comprise a resource block in an OFDM symbol. The mapping of the coded and modulated DCI on the resource elements may be based on mapping of CCEs and REGs (e.g., CCE-to-REG mapping).

[0213] FIG. 14A illustrates an example of CORESET configurations for a bandwidth part. The base station may transmit a DCI via a PDCCH on one or more control resource sets (CORESETs). A CORESET may comprise a timefrequency resource in which the UE tries to decode a DCI using one or more search spaces. The base station may configure a CORESET in the time-frequency domain. In the example of FIG. 14A, a first CORESET 1401 and a second CORESET 1402 occur at the first symbol in a slot. The first CORESET 1401 overlaps with the second CORESET 1402 in the frequency domain. A third CORESET 1403 occurs at a third symbol in the slot. A fourth CORESET 1404 occurs at the seventh symbol in the slot. CORESETs may have a different number of resource blocks in frequency domain. [0214] FIG. 14B illustrates an example of a CCE-to-REG mapping for DCI transmission on a CORESET and PDCCH processing. The CCE-to-REG mapping may be an interleaved mapping (e.g., for the purpose of providing frequency diversity) or a non-interleaved mapping (e.g., for the purposes of facilitating interference coordination and/or frequency- selective transmission of control channels). The base station may perform different or same CCE-to-REG mapping on different CORESETs. A CORESET may be associated with a CCE-to-REG mapping by RRC configuration. A CORESET may be configured with an antenna port quasi co-location (QCL) parameter. The antenna port GCL parameter may indicate QCL information of a demodulation reference signal (DMRS) for PDCCH reception in the CORESET.

[0215] The base station may transmit, to the UE, RRC messages comprising configuration parameters of one or more CORESETs and one or more search space sets. The configuration parameters may indicate an association between a search space set and a CORESET. A search space set may comprise a set of PDCCH candidates formed by CCEs at a given aggregation level. The configuration parameters may indicate: a number of PDCCH candidates to be monitored per aggregation level; a PDCCH monitoring periodicity and a PDCCH monitoring pattern; one or more DCI formats to be monitored by the UE; and/or whether a search space set is a common search space set or a UE- specific search space set. A set of CCEs in the common search space set may be predefined and known to the UE. A set of CCEs in the UE-specific search space set may be configured based on the UE’s identity (e.g., C-RNTI).

[0216] As shown in FIG. 14B, the UE may determine a time-frequency resource for a CORESET based on RRC messages. The UE may determine a CCE-to-REG mapping (e.g., interleaved or non-interleaved, and/or mapping parameters) for the CORESET based on configuration parameters of the CORESET. The UE may determine a number (e.g., at most 10) of search space sets configured on the CORESET based on the RRC messages. The UE may monitor a set of PDCCH candidates according to configuration parameters of a search space set. The UE may monitor a set of PDCCH candidates in one or more CORESETs for detecting one or more DCIs. Monitoring may comprise decoding one or more PDCCH candidates of the set of the PDCCH candidates according to the monitored DCI formats. Monitoring may comprise decoding a DCI content of one or more PDCCH candidates with possible (or configured) PDCCH locations, possible (or configured) PDCCH formats (e.g., number of CCEs, number of PDCCH candidates in common search spaces, and/or number of PDCCH candidates in the UE-specific search spaces) and possible (or configured) DCI formats. The decoding may be referred to as blind decoding. The UE may determine a DCI as valid for the UE, in response to CRC checking (e.g., scrambled bits for CRC parity bits of the DCI matching a RNTI value). The UE may process information contained in the DCI (e.g., a scheduling assignment, an uplink grant, power control, a slot format indication, a downlink preemption, and/or the like).

[0217] The UE may transmit uplink control signaling (e.g., uplink control information (UCI)) to a base station. The uplink control signaling may comprise hybrid automatic repeat request (HARQ) acknowledgements for received DL- SCH transport blocks. The UE may transmit the HARQ acknowledgements after receiving a DL-SCH transport block. Uplink control signaling may comprise channel state information (CSI) indicating channel quality of a physical downlink channel. The UE may transmit the CSI to the base station. The base station, based on the received CSI, may determine transmission format parameters (e.g., comprising multi-antenna and beamforming schemes) for a downlink transmission. Uplink control signaling may comprise scheduling requests (SR). The UE may transmit an SR indicating that uplink data is available for transmission to the base station. The UE may transmit a UCI (e.g. , HARQ acknowledgements (HARQ-ACK), CSI report, SR, and the like) via a physical uplink control channel (PUCOH) or a physical uplink shared channel (PUSCH). The UE may transmit the uplink control signaling via a PUCOH using one of several PUCOH formats.

[0218] There may be five PUCCH formats and the UE may determine a PUCCH format based on a size of the UCI (e.g., a number of uplink symbols of UCI transmission and a number of UCI bits). PUCCH format 0 may have a length of one or two OFDM symbols and may include two or fewer bits. The UE may transmit UCI in a PUCCH resource using PUCCH format 0 if the transmission is over one or two symbols and the number of HARQ-ACK information bits with positive or negative SR (HARQ-ACK/SR bits) is one or two. PUCCH format 1 may occupy a number between four and fourteen OFDM symbols and may include two or fewer bits. The UE may use PUCCH format 1 if the transmission is four or more symbols and the number of HARQ-ACK/SR bits is one or two. PUCCH format 2 may occupy one or two OFDM symbols and may include more than two bits. The UE may use PUCCH format 2 if the transmission is over one or two symbols and the number of UCI bits is two or more. PUCCH format 3 may occupy a number between four and fourteen OFDM symbols and may include more than two bits. The UE may use PUCCH format 3 if the transmission is four or more symbols, the number of UCI bits is two or more and PUCCH resource does not include an orthogonal cover code. PUCCH format 4 may occupy a number between four and fourteen OFDM symbols and may include more than two bits. The UE may use PUCCH format 4 if the transmission is four or more symbols, the number of UCI bits is two or more and the PUCCH resource includes an orthogonal cover code.

[0219] The base station may transmit configuration parameters to the UE for a plurality of PUCCH resource sets using, for example, an RRC message. The plurality of PUCCH resource sets (e.g., up to four sets) may be configured on an uplink BWP of a cell. A PUCCH resource set may be configured with a PUCCH resource set index, a plurality of PUCCH resources with a PUCCH resource being identified by a PUCCH resource identifier (e.g., pucch-Resourceid), and/or a number (e.g. a maximum number) of UCI information bits the UE may transmit using one of the plurality of PUCCH resources in the PUCCH resource set. When configured with a plurality of PUCCH resource sets, the UE may select one of the plurality of PUCCH resource sets based on a total bit length of the UCI information bits (e.g., HARQ- ACK, SR, and/or CSI). If the total bit length of UCI information bits is two or fewer, the UE may select a first PUCCH resource set having a PUCCH resource set index equal to “0”. If the total bit length of UCI information bits is greater than two and less than or equal to a first configured value, the UE may select a second PUCCH resource set having a PUCCH resource set index equal to “1”. If the total bit length of UCI information bits is greater than the first configured value and less than or equal to a second configured value, the UE may select a third PUCCH resource set having a PUCCH resource set index equal to “2”. If the total bit length of UCI information bits is greater than the second configured value and less than or equal to a third value (e.g., 1406), the UE may select a fourth PUCCH resource set having a PUCCH resource set index equal to “3”. [0220] After determining a PUCCH resource set from a plurality of PUCCH resource sets, the UE may determine a PUCCH resource from the PUCCH resource set for UCI (HARQ-ACK, CSI, and/or SR) transmission. The UE may determine the PUCCH resource based on a PUCCH resource indicator in a DCI (e.g., with a DCI format 1_0 or DCI for 1_1) received on a PDCCH. A three-bit PUCCH resource indicator in the DCI may indicate one of eight PUCCH resources in the PUCCH resource set. Based on the PUCCH resource indicator, the UE may transmit the UCI (HARQ- ACK, CSI and/or SR) using a PUCCH resource indicated by the PUCCH resource indicator in the DCI.

[0221] FIG. 15 illustrates an example of a wireless device 1502 in communication with a base station 1504 in accordance with embodiments of the present disclosure. The wireless device 1502 and base station 1504 may be part of a mobile communication network, such as the mobile communication network 100 illustrated in FIG. 1A, the mobile communication network 150 illustrated in FIG. 1 B, or any other communication network. Only one wireless device 1502 and one base station 1504 are illustrated in FIG. 15, but it will be understood that a mobile communication network may include more than one UE and/or more than one base station, with the same or similar configuration as those shown in FIG. 15.

[0222] The base station 1504 may connect the wireless device 1502 to a core network (not shown) through radio communications over the air interface (or radio interface) 1506. The communication direction from the base station 1504 to the wireless device 1502 over the air interface 1506 is known as the downlink, and the communication direction from the wireless device 1502 to the base station 1504 over the air interface is known as the uplink. Downlink transmissions may be separated from uplink transmissions using FDD, TDD, and/or some combination of the two duplexing techniques.

[0223] In the downlink, data to be sent to the wireless device 1502 from the base station 1504 may be provided to the processing system 1508 of the base station 1504. The data may be provided to the processing system 1508 by, for example, a core network. In the uplink, data to be sent to the base station 1504 from the wireless device 1502 may be provided to the processing system 1518 of the wireless device 1502. The processing system 1508 and the processing system 1518 may implement layer 3 and layer 2 OSI functionality to process the data for transmission. Layer 2 may include an SDAP layer, a PDCP layer, an RLC layer, and a MAC layer, for example, with respect to FIG. 2A, FIG. 2B, FIG. 3, and FIG. 4A. Layer 3 may include an RRC layer as with respect to FIG. 2B.

[0224] After being processed by processing system 1508, the data to be sent to the wireless device 1502 may be provided to a transmission processing system 1510 of base station 1504. Similarly, after being processed by the processing system 1518, the data to be sent to base station 1504 may be provided to a transmission processing system 1520 of the wireless device 1502. The transmission processing system 1510 and the transmission processing system 1520 may implement layer 1 OSI functionality. Layer 1 may include a PHY layer with respect to FIG. 2A, FIG. 2B, FIG. 3, and FIG. 4A. For transmit processing, the PHY layer may perform, for example, forward error correction coding of transport channels, interleaving, rate matching, mapping of transport channels to physical channels, modulation of physical channel, multiple-input multiple-output (MIMO) or multi-antenna processing, and/or the like. [0225] At the base station 1504, a reception processing system 1512 may receive the uplink transmission from the wireless device 1502. At the wireless device 1502, a reception processing system 1522 may receive the downlink transmission from base station 1504. The reception processing system 1512 and the reception processing system 1522 may implement layer 1 OSI functionality. Layer 1 may include a PHY layer with respect to FIG. 2A, FIG. 2B, FIG. 3, and FIG. 4A. For receive processing, the PHY layer may perform, for example, error detection, forward error correction decoding, deinterleaving, demapping of transport channels to physical channels, demodulation of physical channels, Ml MO or multi-antenna processing, and/or the like.

[0226] As shown in FIG. 15, a wireless device 1502 and the base station 1504 may include multiple antennas. The multiple antennas may be used to perform one or more Ml MO or multi-antenna techniques, such as spatial multiplexing (e.g., single-user MIMO or multi-user MIMO), transmit/receive diversity, and/or beamforming. In other examples, the wireless device 1502 and/or the base station 1504 may have a single antenna.

[0227] The processing system 1508 and the processing system 1518 maybe associated with a memory 1514 and a memory 1524, respectively. Memory 1514 and memory 1524 (e.g., one or more non-transitory computer readable mediums) may store computer program instructions or code that may be executed by the processing system 1508 and/or the processing system 1518 to carry out one or more of the functionalities discussed in the present application. Although not shown in FIG. 15, the transmission processing system 1510, the transmission processing system 1520, the reception processing system 1512, and/or the reception processing system 1522 may be coupled to a memory (e.g., one or more non-transitory computer readable mediums) storing computer program instructions or code that may be executed to carry out one or more of their respective functionalities.

[0228] The processing system 1508 and/or the processing system 1518 may comprise one or more controllers and/or one or more processors. The one or more controllers and/or one or more processors may comprise, for example, a general-purpose processor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) and/or other programmable logic device, discrete gate and/or transistor logic, discrete hardware components, an on-board unit, or any combination thereof. The processing system 1508 and/or the processing system 1518 may perform at least one of signal coding/processing, data processing, power control, input/output processing, and/or any other functionality that may enable the wireless device 1502 and the base station 1504 to operate in a wireless environment.

[0229] The processing system 1508 and/or the processing system 1518 may be connected to one or more peripherals 1516 and one or more peripherals 1526, respectively. The one or more peripherals 1516 and the one or more peripherals 1526 may include software and/or hardware that provide features and/or functionalities, for example, a speaker, a microphone, a keypad, a display, a touchpad, a power source, a satellite transceiver, a universal serial bus (USB) port, a hands-free headset, a frequency modulated (FM) radio unit, a media player, an Internet browser, an electronic control unit (e.g., for a motor vehicle), and/or one or more sensors (e.g., an accelerometer, a gyroscope, a temperature sensor, a radar sensor, a lidar sensor, an ultrasonic sensor, a light sensor, a camera, and/or the like). The processing system 1508 and/or the processing system 1518 may receive user input data from and/or provide user output data to the one or more peripherals 1516 and/or the one or more peripherals 1526. The processing system 1518 in the wireless device 1502 may receive power from a power source and/or may be configured to distribute the power to the other components in the wireless device 1502. The power source may comprise one or more sources of power, for example, a battery, a solar cell, a fuel cell, or any combination thereof. The processing system 1508 and/or the processing system 1518 may be connected to a GPS chipset 1517 and a GPS chipset 1527, respectively. The GPS chipset 1517 and the GPS chipset 1527 may be configured to provide geographic location information of the wireless device 1502 and the base station 1504, respectively.

[0230] FIG. 16A illustrates an example structure for uplink transmission. A baseband signal representing a physical uplink shared channel may perform one or more functions. The one or more functions may comprise at least one of: scrambling; modulation of scrambled bits to generate complex-valued symbols; mapping of the complex-valued modulation symbols onto one or several transmission layers; transform precoding to generate complex-valued symbols; precoding of the complex-valued symbols; mapping of precoded complex-valued symbols to resource elements; generation of complex-valued time-domain Single Carrier-Frequency Division Multiple Access (SC-FDMA) or CP- OFDM signal for an antenna port; and/or the like. In an example, when transform precoding is enabled, a SC-FDMA signal for uplink transmission may be generated. In an example, when transform precoding is not enabled, a CP-OFDM signal for uplink transmission may be generated by FIG. 16A. These functions are illustrated as examples and it is anticipated that other mechanisms may be implemented in various embodiments.

[0231] FIG. 16B illustrates an example structure for modulation and up-conversion of a baseband signal to a carrier frequency. The baseband signal may be a complex-valued SC-FDMA or CP-OFDM baseband signal for an antenna port and/or a complex-valued Physical Random Access Channel (PRACH) baseband signal. Filtering may be employed prior to transmission.

[0232] FIG. 16C illustrates an example structure for downlink transmissions. A baseband signal representing a physical downlink channel may perform one or more functions. The one or more functions may comprise: scrambling of coded bits in a codeword to be transmitted on a physical channel; modulation of scrambled bits to generate complexvalued modulation symbols; mapping of the complex-valued modulation symbols onto one or several transmission layers; precoding of the complex-valued modulation symbols on a layer for transmission on the antenna ports; mapping of complex-valued modulation symbols for an antenna port to resource elements; generation of complex-valued timedomain OFDM signal for an antenna port; and/or the like. These functions are illustrated as examples and it is anticipated that other mechanisms may be implemented in various embodiments.

[0233] FIG. 16D illustrates another example structure for modulation and up-conversion of a baseband signal to a carrier frequency. The baseband signal may be a complex-valued OFDM baseband signal for an antenna port. Filtering may be employed prior to transmission. [0234] A wireless device may receive from a base station one or more messages (e.g. RRC messages) comprising configuration parameters of a plurality of cells (e.g. primary cell, secondary cell). The wireless device may communicate with at least one base station (e.g. two or more base stations in dual connectivity) via the plurality of cells. The one or more messages (e.g. as a part of the configuration parameters) may comprise parameters of physical, MAC, RLC, PCDP, SDAP, RRC layers for configuring the wireless device. For example, the configuration parameters may comprise parameters for configuring physical and MAC layer channels, bearers, etc. For example, the configuration parameters may comprise parameters indicating values of timers for physical, MAC, RLC, PCDP, SDAP, RRC layers, and/or communication channels.

[0235] A timer may begin running once it is started and continue running until it is stopped or until it expires. A timer may be started if it is not running or restarted if it is running. A timer may be associated with a value (e.g. the timer may be started or restarted from a value or may be started from zero and expire once it reaches the value). The duration of a timer may not be updated until the timer is stopped or expires (e.g., due to BWP switching). A timer may be used to measure a time period/window for a process. When the specification refers to an implementation and procedure related to one or more timers, it will be understood that there are multiple ways to implement the one or more timers. For example, it will be understood that one or more of the multiple ways to implement a timer may be used to measure a time period/window for the procedure. For example, a random access response window timer may be used for measuring a window of time for receiving a random access response. In an example, instead of starting and expiry (or expiration) of a random access response window timer, the time difference between two time stamps may be used. When a timer is restarted, a process for measurement of time window may be restarted. Other example implementations may be provided to restart a measurement of a time window.

[0236] A base station may transmit one or more MAC PDUs to a wireless device. In an example, a MAC PDU may be a bit string that is byte aligned (e.g., aligned to a multiple of eight bits) in length. In an example, bit strings may be represented by tables in which the most significant bit is the leftmost bit of the first line of the table, and the least significant bit is the rightmost bit on the last line of the table. More generally, the bit string may be read from left to right and then in the reading order of the lines. In an example, the bit order of a parameter field within a MAC PDU is represented with the first and most significant bit in the leftmost bit and the last and least significant bit in the rightmost bit.

[0237] In an example, a MAC SDU may be a bit string that is byte aligned (e.g., aligned to a multiple of eight bits) in length. In an example, a MAC SDU may be included in a MAC PDU from the first bit onward. A MAC CE may be a bit string that is byte aligned (e.g., aligned to a multiple of eight bits) in length. A MAC subheader may be a bit string that is byte aligned (e.g., aligned to a multiple of eight bits) in length. In an example, a MAC subheader may be placed immediately in front of a corresponding MAC SDU, MAC CE, or padding. A MAC entity may ignore a value of reserved bits in a DL MAC PDU. [0238] In an example, a MAC PDU may comprise one or more MAC subPDUs. A MAC subPDU of the one or more MAC subPDUs may comprise: a MAC subheader only (including padding); a MAC subheader and a MAC SDU; a MAC subheader and a MAC CE; a MAC subheader and padding, or a combination thereof. The MAC SDU may be of variable size. A MAC subheader may correspond to a MAC SDU, a MAC CE, or padding.

[0239] In an example, when a MAC subheader corresponds to a MAC SDU, a variable-sized MAC CE, or padding, the MAC subheader may comprise: a Reserve field (R field) with a one bit length; an Format field (F field) with a one-bit length; a Logical Channel Identifier (LCID) field with a multi-bit length; a Length field (L field) with a multi-bit length, indicating the length of the corresponding MAC SDU or variable-size MAC CE in bytes, or a combination thereof. In an example, F field may indicate the size of the L field.

[0240] In an example, a MAC entity of the base station may transmit one or more MAC CEs (e.g., MAC CE commands) to a MAC entity of a wireless device. The one or more MAC CEs may comprise at least one of: a SP ZP CSI-RS Resource Set Activation/Deactivation MAC CE, a PUCCH spatial relation Activation/Deactivation MAC CE, a SP SRS Activation/Deactivation MAC CE, a SP CSI reporting on PUCCH Activation/Deactivation MAC CE, a TCI State Indication for UE-specific PDCCH MAC CE, a TCI State Indication for UE-specific PDSCH MAC CE, an Aperiodic CSI Trigger State Subselection MAC CE, a SP CSI-RS/CSI-IM Resource Set Activation/Deactivation MAC CE, a UE contention resolution identity MAC CE, a timing advance command MAC CE, a DRX command MAC CE, a Long DRX command MAC CE, an SCell activation/deactivation MAC CE (1 Octet), an SCell activation/deactivation MAC CE (4 Octet), and/or a duplication activation/deactivation MAC CE. In an example, a MAC CE, such as a MAC CE transmitted by a MAC entity of the base station to a MAC entity of the wireless device, may have an LCID in the MAC subheader corresponding to the MAC CE. In an example, a first MAC CE may has a first LCID in the MAC subheader that may be different than the second LCID in the MAC subheader of a second MAC CE. For example, an LCID given by 111011 in a MAC subheader may indicate that the MAC CE associated with the MAC subheader is a Long DRX command MAC CE.

[0241] In an example, the MAC entity of the wireless device may transmit to the MAC entity of the base station one or more MAC CEs. The one or more MAC CEs may comprise at least one of: a short buffer status report (BSR) MAC CE, a long BSR MAC CE, a C-RNTI MAC CE, a configured grant confirmation MAC CE, a single entry PHR MAC CE, a multiple entry PHR MAC CE, a Short truncated BSR, and/or a Long truncated BSR. In an example, a MAC CE may have an LCID in the MAC subheader corresponding to the MAC CE. In an example, a first MAC CE may has a first LCID in the MAC subheader that may be different than the second LCID in the MAC subheader of a second MAC CE. For example, an LCID given by 111011 in a MAC subheader may indicate that a MAC CE associated with the MAC subheader is a short-truncated command MAC CE.

[0242] A wireless device may receive (e.g., from a base station and/or via a cell), one or more messages. The one or more messages may comprise one or more RRC messages. The wireless device may receive at least one message of the one or more messages via/using one or more PDSCHs/TBs. The wireless device may receive at least one message of the one or more messages via/using one or more DCIs or control channels. The wireless device may receive at least one message of the one or more messages via/using one or more MAC CEs The one or more messages may comprise/indicate one or more configuration parameters for communicating (e.g., transmitting and/or receiving) one or more signals/channels.

[0243] For example, the one or more RRC messages may correspond to broadcast or multicast or group cast downlink messages (e.g., SIBs). For example, the one or more RRC messages may correspond to unicast downlink messages and/or dedicated downlink messages.

[0244] The one or more channels/signals may comprise one or more DL signals/channels, e.g., PDSCH/CSI- RS/PDCCH/SSB/WUS (wake up signal) or the like. The one or more channels/signals may comprise one or more UL signals/channels, e.g., PUSCH/SRS/PUCCH/WUS or the like.

[0245] The one or more configuration parameters may, for example, comprise/configure/indicate one or more serving cell (e.g., the one or more Serving Cells or the one or more cells) configuration parameters (e.g., ServingCellConfigCommon, Sen/ingCellConfigCommonSIB, and/or ServingCellConfig). The one or more serving cell configuration parameters may be for configuring one or more cells (e.g., the one or more Serving Cells). For example, the one or more cells may comprise a master (or primary) cell group (MSG) and/or a secondary cell group (SCG). [0246] In some cases, a cell of the one or more cells may be a primary secondary cell (PSCell), or a primary cell (PCell), or a secondary cell (SCell), or a special cell (SpCell). In some other cases, a cell of the one or more cells may belong to a first cell group corresponding to a primary TAG (pTAG) or a second cell group corresponding to a secondary TAG (sTAG). For example, the one or more configuration parameters may configure the wireless device for multi-cell communication and/or carrier aggregation.

[0247] The one or more configuration parameters may comprise configuration parameters of one or more BWPs (e.g., one or more BWP configuration parameters). The one or more BWP configuration parameters may comprise parameters of the cell and one or more BWPs associated with the cell. Among the one or more BWPs, at least one BWP may be configured as the first active BWP (e.g., BWP 1), one BWP as the default BWP (e.g., BWP 0). In some cases, the wireless device may receive a command (e.g., an RRC message, a MAC CE or a DCI) to activate the cell at a slot. In some other cases (e.g., when the cell is a PCell), the wireless device may activate the cell (e.g., PCell) once the wireless device receives the command (e.g., the RRC message) comprising configuration parameters of the PCell. The wireless device may start monitoring a PDCCH (e.g., monitoring PDCCH candidates) on BWP 1, e.g., in response to activating the cell.

[0248] In carrier aggregation (CA), two or more component carriers (CCs) may be aggregated. The wireless device may, using the technique of CA, simultaneously receive or transmit on one or more CCs, depending on capabilities of the wireless device. In an example, the wireless device may support CA for contiguous CCs and/or for non-contiguous CCs. CCs may be organized into cells. For example, CCs may be organized into one primary cell (PCell) and one or more secondary cells (SCells). [0249] When configured with CA, the wireless device may have one RRC connection with a network. During an RRC connection establishment/re-establishment/handover, a cell providing NAS mobility information may be a serving cell. During an RRC connection re-establishment/handover procedure, a cell providing a security input may be the serving cell. In an example, the serving cell may be a PCell.

[0250] In an example, the one or mor configuration parameters may comprise configuration parameters of a plurality of one or more SCells, depending on capabilities of the wireless device. When configured with CA, the base station and/or the wireless device may employ an activation/deactivation mechanism of an SCell to improve battery or power consumption of the wireless device. When the wireless device is configured with one or more SCells, the base station may activate or deactivate at least one of the one or more SCells. Upon configuration of an SCell, the SCell may be deactivated unless the SCell state associated with the SCell is set to “activated” or “dormant.” The wireless device may activate/deactivate the SCell in response to receiving an SCell Activation/Deactivation MAC CE.

[0251] For example, the base station may configure (e.g., via the one or more RRC messages/parameters) the wireless device with uplink (UL) bandwidth parts (BWPs) and downlink (DL) BWPs to enable bandwidth adaptation (BA) on a PCell. If carrier aggregation (CA) is configured, the base station may further configure the wireless device with at least one DL BWP (e.g., there may be no UL BWP in the UL) to enable BA on an SCell. For the PCell, an initial active BWP may be a first BWP used for initial access. In paired spectrum (e.g., FDD), the base station and/or the wireless device may independently switch a DL BWP and an UL BWP. In unpaired spectrum (e.g., TDD), the base station and/or the wireless device may simultaneously switch the DL BWP and the UL BWP.

[0252] A serving cell may be a cell (e.g., PCell, SCell, PSCell, etc.) on which the wireless device may receive SSB/CSI-RS/PDCCH/PDSCH and/or may transmit PUCCH/PUSCH/SRS etc. The serving cell is identified by a serving cell index (e.g., ServCelllndex or SCelllndex configured/indicated by the one or more configuration parameters). For a wireless device in RRC_CONNECTED not configured with CA/DC, there may only be one serving cell comprising of a primary cell. For a wireless device in RRC_CONNECTED configured with CA/ DC the term 'serving cells' may be used to denote a set of cells comprising of the Special Cell(s) and one or more (e.g., all) secondary cells. For a wireless device configured with CA, a cell providing additional radio resources on top of Special Cell is referred to as a secondary cell.

[0253] A non-serving (or neighbor) cell may be a cell on which the wireless device may not receive

Ml Bs/SI Bs/PDCCH/PDSCH and/or may not transmit PUCCH/PUSCH/SRS etc. The non-serving cell has a physical cell identifier (PCI) different from a PCI of a serving cell. The non-serving cell may not be identified by (or associated with) a serving cell index (e.g., ServCelllndex or SCelllndex). The wireless device may rely on an SSB of a non-serving cell for Tx/Rx beam (or spatial domain filter) determination (for PDCCH/PDSCH/PUCCH/PUSCH/CSI-RS/SRS for a serving cell, etc.), e.g., when a TCI state of the serving cell is associated with (e.g., in TCI-state IE of TS 38.331) a SSB of the non-serving cell. The base station may not transmit configuring resources/parameters of PDCCH/PDSCH/PUCCH/PUSCH/SRS of a non-serving cell to the wireless device. [0254] In an example, the base station and/or the wireless device may switch a BWP between configured BWPs by means of a DOI or a BWP invalidity timer. When the BWP invalidity timer is configured for the serving cell, the base station and/or the wireless device may switch the active BWP to a default BWP in response to the expiry of the BWP invalidity timer associated with the serving cell. The default BWP may be configured by the network. In an example, for FDD systems, when configured with BA, one UL BWP for each uplink carrier and one DL BWP may be active at a time in the active serving cell. In an example, for TDD systems, one DL/UL BWP pair may be active at a time in the active serving cell. Operating on one UL BWP and one DL BWP (or one DL/UL pair) may improve the wireless device battery consumption. One or more BWPs other than the active UL BWP and the active DL BWP, which the wireless device may work on, may be deactivated. On the deactivated one or more BWPs, the wireless device may: not monitor PDCCH; and/or not transmit on PUCCH, PRACH, and UL-SCH. In an example, the MAC entity of the wireless device may apply normal operations on the active BWP for an activated serving cell configured with a BWP comprising: transmitting on UL-SCH; transmitting on RACH; monitoring a PDCCH; transmitting PUCCH; receiving DL-SCH; and/or (re-)initializing any suspended configured uplink grants of configured grant Type 1 according to a stored configuration, if any. In an example, on the inactive/idle BWP for each activated serving cell configured with a BWP, the MAC entity of the wireless device may: not transmit on UL-SCH; not transmit on RACH; not monitor a PDCCH; not transmit PUCCH; not transmit SRS, not receive DL-SCH; clear any configured downlink assignment and configured uplink grant of configured grant Type 2; and/or suspend any configured uplink grant of configured Type 1.

[0255] In an example, a DCI addressed to an RNTI may comprise a CRC of the DCI being scrambled with the RNTI. The wireless device may monitor PDCCH addressed to (or for) the RNTI for detecting the DCI. For example, the PDCCH may carry (or be with) the DCI. In an example, the PDCCH may not carry the DCI.

[0256] In an example, a set of PDCCH candidates for the wireless device to monitor is defined in terms of one or more search space sets. A search space set may comprise a common search space (CSS) set or a UE-specific search space (USS) set. The wireless device may monitor one or more PDCCH candidates in one or more of the following search space sets (e.g., one or more search space sets): a TypeO-PDCCH CSS set configured by pdcch-ConfigSI B 1 in MIB or by searchSpaceSI B 1 in PDCCH-ConfigCommon or by searchSpaceZero in PDCCH-ConfigCommon for a DCI format with CRC scrambled by a SI-RNTI on the primary cell of the MCG, a TypeOA-PDCCH CSS set configured by searchSpaceOtherSystemlnformation in PDCCH-ConfigCommon for a DCI format with CRC scrambled by the SI-RNTI on the primary cell of the MCG, a Typel -PDCCH CSS set configured by ra-SearchSpace in PDCCH-ConfigCommon for a DCI format with CRC scrambled by a RA-RNTI, a MSGB-RNTI, or a TC-RNTI on the primary cell, a Type2- PDCCH CSS set configured by pagingSearchSpace in PDCCH-ConfigCommon for a DCI format with CRC scrambled by a P-RNTI on the primary cell of the MCG, a Type3-PDCCH CSS set configured by SearchSpace in PDCCH-Config with searchSpaceType = common for DCI formats with CRC scrambled by a I NT-RNTI, a SFI-RNTI, a TPC-PUSCH- RNTI, a TPC-PUCCH-RNTI, a TPC-SRS-RNTI, a CI-RNTI, or a power saving RNTI (PS-RNTI) and, only for the primary cell, a C-RNTI, a MCS-C-RNTI, or a CS-RNTI(s), and the USS set configured by SearchSpace in PDCCH-Config with searchSpaceType = ue-Specific for DOI formats with ORC scrambled by the C-RNTI, the MCS-C-RNTI, a SP-CSI- RNTI, the CS-RNTI(s), a SL-RNTI, a SL-CS-RNTI, or a SL-L-CS-RNTI.

[0257] In an example, the wireless device may monitor the one or more PDCCH candidates according to one or more configuration parameters of the search space set. For example, the search space set may comprise a plurality of search spaces (SSs). The wireless device may monitor the one or more PDCCH candidates in one or more CORESETs for detecting one or more DCIs. Monitoring the one or more PDCCH candidates may comprise decoding at least one PDCCH candidate of the one or more PDCCH candidates according to the monitored DCI formats. For example, monitoring the one or more PDCCH candidates may comprise decoding (e.g., blind decoding) a DCI content of the at least one PDCCH candidate via possible (or configured) PDCCH location(s), possible (or configured) PDCCH format(s), e.g., number of CCEs, number of PDCCH candidates in CSS set(s), and/or number of PDCCH candidates in the USS(s), and/or possible (or configured) DCI format(s).

[0258] In an example, the wireless device may receive the C-RNTI (e.g., via one or mor previous transmissions) from the base station. For example, the one or more previous transmissions may comprise a Msg2 1312, Msg41314, or a MsgB 1332. If the wireless device is not provided the Type3-PDCCH CSS set or the USS set and if provided the Typel -PDCCH CSS set, the wireless device may monitor the one or more PDCCH candidates for DCI format 0_0 and DCI format 1_0 with CRC scrambled by the C-RNTI in the Typel-PDCCH CSS set.

[0259] For example, the one or more search space sets may correspond to one or more of searchSpaceZero, searchSpaceSIBI, searchSpaceOtherSystemlnformation, pagingSearchSpace, ra-SearchSpace, and the C-RNTI, the MCS-C-RNTI, or the CS-RNTI. The wireless device may monitor the one or more PDCCH candidates for the DCI format 0_0 and the DCI format 1_0 with CRC scrambled by the C-RNTI, the MCS-C-RNTI, or the CS-RNTI in the one or more search space sets in a slot where the wireless device monitors the one or more PDCCH candidates for at least the DCI format 0_0 or the DCI format 1_0 with CRC scrambled by the SI-RNTI, the RA-RNTI, the MSGB-RNTI, or the P-RNTI.

[0260] The base station may use the DCI formats to transmit downlink control information to the wireless device. In an example, the wireless device may use the DCI formats for PDCCH monitoring. Different DCI formats may comprise different DCI fields and/or have different DCI payload sizes. Different DCI formats may have different signaling purposes. For example, DCI format 0_0 may be used to schedule PUSCH in one cell. DCI format 0 J may be used to schedule one or multiple PUSCH in one cell or indicate CG-DFI (configured grant-Downlink Feedback Information) for configured grant PUSCH, etc.

[0261] In an example, the wireless device may support a baseline processing time/capability. For example, the wireless device may support additional aggressive/faster processing time/capability. In an example, the wireless device may report to the base station a processing capability, e.g., per sub-carrier spacing. In an example, a PDSCH processing time may be considered to determine, by a wireless device, a first uplink symbol of a PUCCH (e.g., determined at least based on a HARQ-ACK timing K1 and one or more PUCCH resources to be used and including the effect of the timing advance) comprising the HARQ-ACK information of the PDSCH scheduled by a DOI. In an example, the first uplink symbol of the PUCCH may not start earlier than a time gap (e.g., T_{proc l}) after a last symbol of the PDSCH reception associated with the HARQ-ACK information. In an example, the first uplink symbol of the PUCCH which carries the HARQ-ACK information may start no earlier than at symbol L1, where L1 is defined as the next uplink symbol with its Cyclic Prefix (CP) starting after the time gap T_{proc l} after the end of the last symbol of the PDSCH. [0262] In an example, a PUSCH preparation/processing time may be considered for determining the transmission time of an UL data. For example, if the first uplink symbol in the PUSCH allocation for a transport block (including DM- RS) is no earlier than at symbol L2, the wireless device may perform transmitting the PUSCH. In an example, the symbol L2 may be determined, by a wireless device, at least based on a slot offset (e.g., K2), SLIV of the PUSCH allocation indicated by time domain resource assignment of a scheduling DCI. In an example, the symbol L2 may be specified as the next uplink symbol with its CP starting after a time gap with length T_{proc 2} after the end of the reception of the last symbol of the PDCCH carrying the DCI scheduling the PUSCH.

[0263] A wireless device may monitor a set of PDCCH candidates according to configuration parameters of a search space set comprising a plurality of search spaces (SSs). The wireless device may monitor a set of PDCCH candidates in one or more CORESETs for detecting one or more DCIs. The one or more configuration parameters may configure the one or more CORESETs. Monitoring (e.g., of the PDCCH) may comprise decoding one or more PDCCH candidates of the set of the PDCCH candidates according to monitored DCI formats. Monitoring (e.g., of the PDCCH) may comprise decoding a DCI content of one or more PDCCH candidates with possible (or configured) PDCCH locations, possible (or configured) PDCCH formats (e.g., number of CCEs, number of PDCCH candidates in common SSs, and/or number of PDCCH candidates in the UE-specific SSs) and/or possible (or configured) DCI formats. The decoding (e.g., of the PDCCH) may be a blind decoding. The one or more configuration parameters may configure the wireless device with DCI format(s) by which the wireless device may monitor the PDCCH in an SS of the plurality of SSs.

[0264] The one or more configuration parameters may comprise a configuration parameters of a master information block (MIB) of a cell (e.g., PCell). The wireless device may receive the MIB via a PBCH. The configuration parameters of the MIB may comprise six bits (systemFrameNumber) of system frame number (SFN), subcarrier spacing indication (subCarrierSpacingCommon), a frequency domain offset (ssb-SubcarrierOffset) between SSB and overall resource block grid in number of subcarriers, an indication (cell Barred) indicating whether the cell is bared, a DMRS position indication (dmrs-TypeA-Position) indicating position of DMRS, parameters of CORESET and SS of a PDCCH (pdcch- ConfigSIBI) comprising a common CORESET, a common search space and necessary PDCCH parameters, etc. [0265] The one or more configuration parameters may comprise configuration parameters (e.g., , a pdcch- ConfigSI B1 ) for configuring a CORESETSO and/or a search space with ID #0. In an example, the pdcch-ConfigSI B1 may comprise a first parameter (e.g., control ResourceSetZero) indicating a common ControlResourceSet (CORESET) with ID #0 (e.g., CORESETSO) of an initial BWP of the cell, control ResourceSetZero may be an integer between 0 and 15. Each integer between 0 and 15 may identify a configuration of CORESETSO. Based on a value of the integer of controlResourceSetZero, the wireless device may determine a SSB and CORESETSO multiplexing pattern, a number of RBs for CORESETSO, a number of symbols for CORESETSO, an RB offset for CORESETSO.

[0266] In some cases, the pdcch-ConfigSI B1 may comprise a second parameter (e.g., searchSpaceZero) indicating a common search space with ID #0 (e.g., SS#0) of the initial BWP of the cell. searchSpaceZero may be an integer between 0 and 15. Each integer between 0 and 15 may identify a configuration of SS#0. Based on a value of the integer of searchSpaceZero, the wireless device may determine one or more parameters (e.g., 0, M) for slot determination of PDCOH monitoring, a first symbol index for PDCOH monitoring and/or a number of search spaces per slot.

[0267] In an example, based on receiving the MIB, the wireless device may monitor PDCOH via SS#0 of CORESETSO for receiving a DOI scheduling a system information block 1 (SIB1). The wireless device may receive the DOI with ORO scrambled with a system information radio network temporary identifier (SI-RNTI) dedicated for receiving the SIB1.

[0268] A SIB (e.g., SIB1) may be transmitted to all wireless devices in a broadcast way. The SIB may contain information relevant when evaluating if a wireless device is allowed to access a cell, information of paging configuration and/or scheduling configuration of other system information. A SIB may contain radio resource configuration information that is common for all wireless devices and barring information applied to a unified access control. In an example, a base station may transmit to the wireless device (or a plurality of wireless devices) one or more SIB information. The one or more configuration parameters may comprise parameters of the one or more SIB information. For example, parameters of the one or more SIB information may comprise: one or more parameters (e.g., cel (Selection I nfo) for cell selection related to a serving cell; and/or one or more configuration parameters of a serving cell (e.g., in ServingCellConfigOommonSIB IE); and/or one or more other parameters. The ServingCellConfigOommonSIB IE may comprise at least one of: common downlink parameters (e.g., in DownlinkConfigOommonSIB IE) of the serving cell; and/or common uplink parameters (e.g., in UplinkConfigOommonSIB IE) of the serving cell; and/or and other parameters.

[0269] In an example, a DownlinkConfigOommonSIB IE may comprise parameters of an initial downlink BWP (initial DownlinkBWP IE) of the serving cell (e.g., SpOell). The parameters of the initial downlink BWP may be comprised in a BWP-DownlinkCommon IE. The BWP-DownlinkCommon IE may be used to configure common parameters of a downlink BWP of the serving cell. The base station may configure the locationAnd Bandwidth for the wireless device so that the initial downlink BWP contains the entire CORESETSO of this serving cell in the frequency domain. The wireless device may apply the locationAnd Bandwidth upon reception of this field (e.g., to determine the frequency position of signals described in relation to this locationAndBandwidth) but it keeps CORESETSO until after reception of RRCSetup/RRCResume/RRCReestablishment.

[0270] In an example, the DownlinkConfigOommonSIB IE may comprise parameters of a paging channel configuration. The parameters may comprise a paging cycle value (T, by defaultPagingCycle IE), a parameter (nAndPagingFrameOffset IE) indicating total number N) of paging frames (PFs) and paging frame offset (PF_offset) in a paging DRX cycle, a number (Ns) for total paging occasions (POs) per PF, a first PDCCH monitoring occasion indication parameter (firstPDCCH-MonitoringOccasionofPO IE) indicating a first PDCCH monitoring occasion for paging of each PC of a PF. The wireless device, based on parameters of a PCCH configuration, may monitor PDCCH for receiving paging message.

[0271] In an example, the parameter first-PDCCH-MonitoringOccasionOfPO may be signaled in SIB1 for paging in initial DL BWP. For paging in a DL BWP other than the initial DL BWP, the parameter first-PDCCH- MonitoringOccasionOfPO may be signaled in the corresponding BWP configuration.

[0272] The one or more configuration parameters may comprise one or more BWP configuration parameters. The one or more BWP configuration parameters may configure a downlink BWP of a serving cell (e.g., BWP- DownlinkCommon IE). A base station may transmit to the wireless device (or a plurality of wireless devices) one or more configuration parameters of the downlink BWP (e.g., the initial downlink BWP) of a serving cell. The one or more BWP configuration parameters of the downlink BWP may comprise: one or more generic BWP parameters of the downlink BWP, one or more cell specific parameters for PDCCH of the downlink BWP (e.g., in pdcch-ConfigCommon IE), one or more cell specific parameters for the PDSCH of this BWP (e.g., in pdsch-ConfigCommon IE), and one or more other parameters. A pdcch-ConfigCommon IE may comprise parameters of COESET #0 (e.g., controlResourceSetZero) which may be used in any common or UE-specific search spaces. A value of the controlResourceSetZero may be interpreted like the corresponding bits in MIB pdcch-ConfigSI B1. A pdcch- ConfigCommon IE may comprise parameters (e.g., in commonControlResourceSet) of an additional common control resource set which may be configured and used for any common or UE-specific search space. If the network configures this field, it uses a Control ResourceSetld other than 0 for this ControlResourceSet. The network configures the commonControlResourceSet in SIB1 so that it is contained in the bandwidth of CORESETSO. A pdcch-ConfigCommon IE may comprise parameters (e.g., in commonSearchSpaceList) of a list of additional common search spaces. A pdcch- ConfigCommon IE may indicate, from a list of search spaces, a search space for paging (e.g., pagingSearchSpace), a search space for random access procedure (e.g., ra-SearchSpace), a search space for SIB1 message (e.g., searchSpaceSI B 1 ), a common search spaceSO (e.g., searchSpaceZero), and one or more other search spaces.

[0273] A control resource set (CORESET) may be associated with a CORESET index (e.g., ControlResourceSetld). A CORESET may be implemented based on example embodiments described above with respect to FIG. 14A and/or FIG. 14B. The CORESET index with a value of 0 may identify a common CORESET configured in MIB and in ServingCellConfigCommon (controlResourceSetZero) and may not be used in the ControlResourceSet IE. The CORESET index with other values may identify CORESETs configured by dedicated signaling or in SIB1. The ControlResourceSetld is unique among the BWPs of a serving cell. A CORESET may be associated with coresetPoollndex indicating an index of a CORESET pool for the CORESET. A CORESET may be associated with a time duration parameter (e.g., duration) indicating contiguous time duration of the CORESET in number of symbols. [0274] The one or more configuration parameters may comprise configuration parameters of a CORESET. For example, the configuration parameters of a CORESET may comprise at least one of: frequency resource indication (e.g., frequencyDomainResources), a COE-REG mapping type indicator (e.g., cce-REG-MappingType), a plurality of TCI states, an indicator indicating whether a TCI is present in a DCI, and the like. The frequency resource indication, comprising a number of bits (e.g., 45 bits), may indicate frequency domain resources, each bit of the indication corresponding to a group of 6 RBs, with grouping starting from the first RB group in a BWP of a cell (e.g., SpCell, SCell). The first (left-most / most significant) bit may correspond to the first RB group in the BWP, and so on. A bit that is set to 1 may indicate that an RB group, corresponding to the bit, belongs to the frequency domain resource of this CORESET. Bits corresponding to a group of RBs not fully contained in the BWP within which the CORESET is configured may be set to zero.

[0275] The one or more configuration parameters may comprise one or more search space configuration parameters. The one or more search space configuration parameters may comprise configuration parameters of one or more SSs (e.g., SearchSpace IE). In an example, configuration parameters of a search space (of the one or more SSs) may comprise at least one of: a search space ID (searchSpaceld), a control resource set ID (control ResourceSetld), a monitoring slot periodicity and offset parameter (monitoringSlotPeriodicityAndOffset), a search space time duration value (duration), a monitoring symbol indication (monitoringSymbolsWithinSlot), a number of candidates for an aggregation level (nrofCandidates), and/or a SS type indicating a common SS type or a UE-specific SS type (searchSpaceType). The monitoring slot periodicity and offset parameter may indicate slots (e.g., in a radio frame) and slot offset (e.g., related to a starting of a radio frame) for PDCOH monitoring. The monitoring symbol indication may indicate on which symbol(s) of a slot a wireless device may monitor PDCOH on the SS. The control resource set ID may identify a control resource set on which a SS may be located.

[0276] In an example, the wireless device, in an RRC idle (e.g., RRC_I DLE or RRCJdle) state/mode or an RRC inactive (e.g., RRC_I NACTIVE or RROJnactive) state/mode, may periodically monitor paging occasions (POs) for receiving paging message for the wireless device. Before monitoring the POs, the wireless device, in RRC_I DLE or RRC_I NACTIVE state, may wake up at a time before each PC for preparation and/or turn all components in preparation of data reception (warm up). The gap between the waking up and the PC may be long enough to accommodate all the processing requirements. The wireless device may perform, after the warming up, timing acquisition from SSB and coarse synchronization, frequency and time tracking, time and frequency offset compensation, and/or calibration of local oscillator. After that, the wireless device may monitor a PDCCH for a paging DCI in one or more PDCCH monitoring occasions based on configuration parameters of the PCCH configuration (e.g., configured in SIB1).

[0277] The base station may transmit one or more SSBs periodically to the wireless device, or a plurality of wireless devices. The wireless device (in RRCJdle state, RRC_inactive state, or RRC_connected state) may use the one or more SSBs for time and frequency synchronization with a cell of the base station. An SSB, comprising a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a physical broadcast channel (PBCH), and a PBCH DM-RS, may be transmitted based on example embodiments described above with respect to FIG. 11 A. An SSB may occupy a number (e.g., 4) of OFDM symbols as shown in FIG. 11A. The base station may transmit one or more SSBs in a SSB burst, e.g., to enable beam-sweeping for PSS/SSS and PBCH. An SSB burst comprises a set of SSBs, each SSB potentially be transmitted on a different beam. SSBs in the SSB burst may be transmitted in time-division multiplexing fashion. In an example, an SSB burst may always be confined to a 5ms window and is either located in first-half or in the second half of a 10ms radio frame. In this specification, an SSB burst may be equivalently referred to as a transmission window (e.g., 5ms) in which the set of SSBs are transmitted.

[0278] The one or more configuration parameters may configure/indicate a transmission periodicity of SSB via the (e.g., ssb-PeriodicityServingCell in ServingCellConfigCommonSIB of SIB1 message). A candidate value of the transmission periodicity may be in a range of {5ms, 10ms, 20ms, 40ms, 80ms, 160ms}. The maximum number of candidate SSBs (Lmax) within an SSB burst depends upon a carrier frequency/band of the cell. In an example, Lmax=4 if fc<=3G Hz, wherein fc is the carrier frequency of the cell. Lmax=8 if 3GHz<fc<=6GHz. Lmax=64 if fc>=6G Hz, etc. [0279] In an example, a starting OFDM symbol index of a candidate SSB (occupying 4 OFDM symbols) within a SSB burst (5ms) may depend on a subcarrier spacing (SOS) and a carrier frequency band of the cell. Starting OFDM symbol indexes of SSBs in a SSB burst, for a cell configured with 15 kHz and carrier frequency fc<3GHz (Lmax=4), are 2, 8, 16, and 22. OFDM symbols in a half-frame are indexed with the first symbol of the first slot being indexed as 0. Starting OFDM symbol indexes of SSBs in a SSB burst, for a cell configured with 15 kHz and carrier frequency 3GHz<fc<6GHz (Lmax=8), are 2, 8, 16, 22, 30, 36, 44 and 50, etc. In an example, when the base station is not transmitting the SSBs with beam forming, the base station may transmit only one SSB by using the first SSB starting position.

[0280] In an example, the base station may transmit to the wireless device (or a plurality of wireless devices) an SSB burst in a periodicity. A default periodicity of an SSB burst may be 20 ms, e.g., before the wireless device receives the SIB1 message for initial access of the cell. The base station, with 20 ms transmission periodicity of SSB (or SSB burst), may transmit the SSB burst in the first 5 ms of each 20 ms. The base station may not transmit the SSB burst in the rest 15 ms of the each 20 ms. The base station may transmit a MIB message with a transmission periodicity of 80 millisecond (ms) to the wireless device. The same MIB message may be repeated (according to the SSB periodicity) within the 80 ms. Contents of the MIB message are same over 80 ms period. The same MIB is transmitted over all SSBs within an SS burst. In an example, PBCH may indicate that there is no associated SIB1, in which case the wireless device may be pointed to another frequency from where to search for an SSB that is associated with a SIB1 as well as a frequency range where the wireless device may assume no SSB associated with SIB1 is present. The indicated frequency range may be confined within a contiguous spectrum allocation of the same operator in which SSB is detected.

[0281] The one or more configuration parameters may (e.g., via SIB1) indicate/comprise cell specific configuration parameters of SSB transmission. The cell specific configuration parameters may comprise a value for a transmission periodicity (ssb-PeriodicityServingCell) of an SSB burst, locations of a number of SSBs (e.g. , active SSBs), of a plurality of candidate SSBs, comprised in the SSB burst. The cell specific configuration parameters may comprise position indication of a SSB in a SSB burst (e.g., ssb-PositionsInBurst). The position indication may comprise a first bitmap (e.g., groupPresence) and a second bitmap (e.g., inOneGroup) indicating locations of a number of SSBs comprised in a SSB burst.

[0282] In an example, the base station may transmit a SIB1 message with a periodicity of 160 ms. The base station may transmit the same SIB1 message with variable transmission repetition periodicity within 160 ms. A default transmission repetition periodicity of SIB1 is 20 ms. The base station may determine an actual transmission repetition periodicity based on network implementation. In an example, for SSB and CORESET multiplexing pattern 1, SIB1 repetition transmission period is 20 ms. For SSB and CORESET multiplexing pattern 2/3, SIB1 transmission repetition period is the same as the SSB period. SIB1 may comprise information regarding the availability and scheduling (e.g., mapping of SIBs to SI message, periodicity, Sl-window size) of other SIBs, an indication whether one or more SIBs are only provided on-demand and in which case, configuration parameters needed by a wireless device to perform an SI request.

[0283] In some implementations, the base station may enable a power saving operation for the wireless device due to limited battery capacity of the wireless device, e.g., based on BWP management, SCell dormancy mechanism, wake-up/go-to-sleep indication, SSSG switching on an active BWP, and/or PDCCH skipping.

[0284] FIG. 17A illustrates an example of a non-terrestrial networks as per an aspect of an embodiment of the present disclosure. The non-terrestrial network (NTN) network (e.g., a satellite network) may be a network or network segment (e.g., an NG-RAN consisting of gNBs) for providing non-terrestrial NR access to wireless devices. The NTN may use a space-borne vehicle to embody a transmission equipment relay node (e.g., radio remote unit or a transparent payload) or a base station (or a regenerative payload). While a terrestrial network is a network located on the surface of the earth, an NTN may be a network which uses an NTN node (e.g., a satellite) as an access network, a backhaul interface network, or both. In an example, an NTN may comprise one or more NTN nodes (or payloads and/or space-borne vehicles), each of which may provide connectivity functions, between the service link and the feeder link. A base station may, via the service link, transmit broadcast signals (e.g., SIBx, x=1, 2, .... 19, ...), multicast signals, and/or dedicated signals to wireless devices, e.g., in a cell.

[0285] An NTN node may embark a bent pipe payload (e.g., a transparent payload) or a regenerative payload. The NTN node with the transparent payload may comprise transmitter/receiver circuitries without the capability of on-board digital signal processing (e.g., modulation and/or coding) and connect to a base station (e.g., a base station of an NTN or the NTN base station or a non-terrestrial access point) via a feeder link. In some respects, as shown in FIG. 17A, the base station (e.g., a gNB/eNB) may further comprise the transparent NTN node, the feeder link, and/or a gateway (e.g., an NTN gateway). The gateway may be an earth station that is located at the surface of the earth, providing connectivity to the NTN payload using a feeder link. In some examples, the NTN node with the regenerative payload (e.g., the base station of the NTN or the NTN base station) may comprise functionalities of a base station, e.g., the onboard processing used to demodulate and decode the received signal and/or regenerate the signal before sending/transmitting it back to the earth. In some respects, as shown in FIG. 17A, the base station (e.g., the gNB) may further comprise the regenerative NTN node, the feeder link, and/or the gateway (e.g., the NTN gateway).

[0286] In some examples, the NTN node may be a satellite, a balloon, an air ship, an airplane, an unmanned aircraft system (UAS), an unmanned aerial vehicle (UAV), a drone, or the like. For example, the UAS may be a blimp, a high- altitude platform station (HAPS), e.g., an airborne vehicle embarking the NTN payload placed at an altitude between 8 and 50 km, or a pseudo satellite station. In an example, a satellite may be placed into a low-earth orbit (LEO) at an altitude between 250 km to 1500 km, with orbital periods ranging from 90- 130 minutes. From the perspective of a given point on the surface of the earth, the position of the LEO satellite may change. In an example, a satellite may be placed into a medium-earth orbit (MEO) at an altitude between 5000 to 20000 km, with orbital periods ranging from 2 hours to 14 hours. In an example, a satellite may be placed into a geostationary satellite earth orbit (GEO) at 35,786 km altitude, and directly above the equator. From the perspective of a given point on the surface of the earth, the position of the GEO satellite may not change.

[0287] FIG. 17B shows an example of UL/DL transmissions when a cell is part of an NTN. The NTN node in FIG. 17B may be with a transparent payload. However, discussions below may equally be applicable for a case that the NTN node is a regenerative payload. As shown in FIG. 17B, the NTN node (e.g., the satellite) may forward a received signal from the NTN gateway on the ground back to the earth over the feeder link. In an example, the gateway and the base station may not be collocated. The NTN node may forward a received signal to the wireless device or the base station from another NTN node, e.g., over inter-link satellite communication links.

[0288] The NTN node may generate one or more beams over a given area (e.g., a coverage area or a cell). The footprint of a beam (or the cell) may be referred to as a spotbeam. For example, the footprint of a cell/beam may move over the Earth’s surface with the satellite movement (e.g., a LEO with moving cells or a HAPS with moving cells). The footprint of a cell/beam may be Earth fixed (e.g., quasi-earth-fixed) with some beam pointing mechanism used by the satellite to compensate for its motion (e.g., a LEO with earth fixed cells). The size of a spotbeam (e.g., diameter of the spotbeam and/or cell and/or coverage area) may range from tens of kilometers (e.g., 50 km - 200 km) to a few thousand kilometers (e.g., 3500 km). For example, the size of the spotbeam may depend on the system design.

[0289] A propagation delay may be an amount of time it takes for the head of the signal to travel from a sender (e.g., the base station or the NTN node) to a receiver (e.g., the wireless device) or vice versa. The propagation delay may vary depending on a change in distance between the sender and the receiver, e.g., due to movement of the NTN node, movement of the wireless device, a change of an inter-satellite link, and/or feeder link switching. One-way latency/delay may be an amount of time required to propagate through a telecommunication system from the sender (e.g., the base station) to the receiver (e.g., the wireless device). For the transparent NTN, the round-trip propagation delay (RTD or UE-gNB RTT) may comprise service link delay (e.g., between the NTN node and the wireless device), feeder link delay (e.g., between the NTN gateway and the NTN node), and/or between the gateway and the base station (e.g., in the case the gateway and the NTN base station are not collocated). For example, the UE-gNB RTT (or the RTD) may be twice of the one-way delay between the wireless device and the base station. In case of a GEO satellite with the transparent payload, the RTD may be approximately 556 milliseconds. A (maximum) RTD of a LEO satellite with the transparent payload and altitude of 600 km is approximately 25.77 milliseconds and with altitude of 1200 km is approximately 41.77 milliseconds. In an example, the RTD of a terrestrial network (e.g., NR, E-UTRA, LTE) may be negligible compared to the RTD of an NTN scenario (e.g., the RTD of a terrestrial network may be less than 1 millisecond).

[0290] A differential delay within a beam/cell of a NTN node may depend on, for example, the maximum diameter of the beam/cell footprint at nadir. For example, the differential delay withing the beam/cell may correspond to a maximum delay link in FIG. 17B. In an example, the differential delay may imply the maximum difference between communication latency that two wireless devices, e.g., a first wireless device (UE1) that is located close to the center of the cell/beam and a second wireless device (UE2) that is located close to the edge of the cell/beam in FIG. 17B, may experience while communicating with the base station via the NTN node. The first wireless device may experience a smaller RTD compared to the second wireless device. The link with a maximum propagation delay (e.g., the maximum delay link) may experience the highest propagation delay (or the maximum RTD) in the cell/beam. In an example, the differential delay may imply a difference between the maximum delay of the cell/beam and a minimum delay of the cell/beam. In an example, the service link to a cell/beam center may experience the minimum propagation delay in the cell/beam. Depending on implementation, for a LEO satellite, the differential delay may be at least 3.12 milliseconds and may increase up to 8 milliseconds. In an example of a GEO satellite, depending on implementation, the differential delay may be as large as 32 milliseconds.

[0291] FIG. 170 shows an example of an NTN assistance information for maintenance of UL synchronization in an NTN scenario. The NTN assistance information may be (or comprise) one or more NTN configuration parameters. [0292] A base station may transmit to the wireless device the NTN assistance information via an NTN-specific SIB (e.g., SIB19) 1700. The one or more messages may comprise the NTN-specific SIB. In some examples, an RRC reconfiguration message (of the one or more messages) may indicate the NTN assistance information.

[0293] The NTN assistance information may comprise a first set of NTN configuration parameters. For example, the first set of NTN configuration parameters may comprise at least one NTN-config (e.g., ntn-config-r17 1720). The at least one NTN-config may correspond to the serving cell of the NTN. The at least one NTN-config may correspond to a source NTN node (e.g., a source satellite) of the serving cell. For example, the at least one NTN-config may correspond to a target NTN node (e.g., target satellite) of the serving cell. For example, the at least one NTN-config may comprise a first NTN configuration (corresponding to the source satellite), e.g., a first NTN-config, and/or a second NTN configuration (corresponding to the target satellite), e.g., a second NTN-config. The wireless device may use the second NTN configuration for/after a satellite switch with synchronization procedure (e.g., a serving link switch with PCI unchanged of the serving cell).

[0294] The NTN assistance information may comprise a second set of NTN configuration parameters. The second set of NTN configuration parameters may correspond to one or more non-serving cell of the NTN (e.g., a target cell or a neighbor cell).

[0295] Each NTN-config (e.g., ntn-Config 1720) of the NTN assistance information may correspond to a cell (e.g., the serving cell or a neighbor cell of the NTN) with a corresponding physical cell ID (PCI). For example, the first/second NTN configurations may correspond to the serving cell (the source cell) with a first PCI.

[0296] As shown in FIG. 17C, the second set of NTN configuration parameters may comprise NTN-configs of one or more NTN neighbor cells (e.g., via ntn-NeighCellConfigList IE) 2710. Each NTN neighbor cell of the one or more NTN neighbor cells may have its unique PCI that is difference than the first PCI. For example, the second set of NTN configuration parameters may not comprise the first/second NTN configurations. The second set of NTN configuration parameters may comprise a third NTN configurations (e.g., a third NTN-config) corresponding to the target cell with a second PCI.

[0297] The at least one NTN-config may comprise the NTN-configs of one or more NTN neighbor cells (e.g., via ntn- NeighCellConfigList IE) 2710.

[0298] The third NTN config may be different than the second NTN config, e.g., when the satellite switch with sync does not comprise/trigger the handover. For example, the target satellite may correspond to the serving cell.

[0299] The third NTN config may be the second NTN config, e.g., when the satellite switch comprises/triggers the handover. For example, the target satellite may correspond to the neighbor cell.

[0300] The second PCI may be different than the first PCI, e.g., for a case of handover procedure or reconfiguration with sync procedure.

[0301] The second PCI may be the first PCI, e.g., for a case of the satellite switch with resync procedure.

[0302] The one or more configuration parameters may comprise common configuration parameters of the serving cell (e.g., IE ServingCellConfigCommon). The serving cell may belong to the NTN. The wireless device may communicate with the base station via the serving cell (of the NTN). The Serving cell may be the first cell (with/identified by the first PCI) and/or the second cell (with/ identified by the second PCI).

[0303] In one example, the base station may transmit to the wireless device the common configuration parameters of the serving cell via a system broadcast information (e.g., SIB1 ). For example, the base station may transmit the common configuration parameters of the serving cell via one or more RRC messages (e.g., RRC setup message, RRC establishment message, RRC re-establishment message, and/or RRC reconfiguration message).

[0304] For example, the base station may transmit the common configuration parameters of the serving cell during the initial access procedure and/or the handover procedure. The common configuration parameters of the serving cell may comprise an NTN-config (e.g., ntn-Config-r17, e.g., corresponding to the serving cell with the first PCI) of the at least one NTN-config.

[0305] In one example, the first set of NTN configuration parameters may comprise the NTN-config of the common configuration parameters of the serving cell (e.g., a first NTN configuration parameters). The first NTN configuration parameters (e.g., the first NTN-config of the at least one NTN-config) may correspond to the first PCI or the first cell (e.g., the source cell). When the common configuration parameters of the serving cell correspond to the RRC setup message (and/or the RRC establishment message and/or RRC re-establishment message), the NTN-config of the common configuration parameters of the serving cell may correspond to the source cell.

[0306] When the common configuration parameters of the serving cell correspond to the RRC reconfiguration message, the NTN-config of the common configuration parameters of the serving cell may correspond to the target cell (e.g., the third NTN configurations e.g., the third NTN-config). The third NTN-config may correspond to the second PCI or the second cell (e.g., the target cell).

[0307] Each/an NTN-config of the NTN assistance information (e.g., NTN-config-r17 1720) may comprise at least one of the following (or a combination of thereof): corresponding ephemeris parameters (or data/information) of an NTN node (e.g., the satellite ephemeris data, e.g., ephemerisinfo); and/or one or more common delay/TA parameters (e.g., ta-lnfo), e.g., comprising at least one of TACommon, TACommonDrift, TACommon Drift ariation; and/or a cell-specific scheduling offset (e.g., cellSpecificKoffset or Koffset, e.g., K_ceu_Off_Set) in number of slots for a given subcarrier spacing (e.g., PKoffset). 15 KHz; and/or MAC-layer scheduling offset (e.g., kmac or K-Mac) in number of slots for a given subcarrier spacing (e.g., 15 KHz, indicating a portion of a feeder link delay that the base station may pre-compensate, e.g., when UL/DL configurations are not aligned at the base station; and/or epoch time for applying the NTN-config (e.g., epochTime); and/or a validity duration of the NTN-config (e.g., ntn-

U ISyncValid ity Du ration) indicating the validity duration of the NTN assistance information; and/or one or more antenna polarization mode(s) (e.g., vertical horizontal, right-hand circular, or left-hand circular) for UL/DL communications (e.g., ntn-Polarization UL/ntn-Polarization DL); and/or a first indication/parameter (e.g., ta-Report-r17).

[0308] The validity duration may be a maximum duration (e.g., in seconds/ms/slots/subframes) that the NTN assistance information stays valid for UL/DL transmissions via the NTN. The validity duration may indicate a maximum duration that the wireless device stays UL synchronized with the serving cell without (re-)acquiring/reading the SIB19 of the serving cell. The validity duration may indicate the maximum duration that the NTN assistance information is applicable for the UL/DL transmission via the NTN. For example, the validity duration may indicate (a maximum/longest) validity period of the (satellite) ephemeris data/information and/or the TA parameters of an NTN- config of the serving cell.

[0309] For example, the MAC-layer scheduling offset may be 0, e.g., when the K-Mac is absent from (is not indicated/configured by) the NTN config of the serving cell. For example, in an NTN scenario with the transparent NTN node, when the UL frame and the DL frame are aligned at the base station, the K-Mac may be absent from the NTN- config of the serving cell.

[0310] To maintain uplink orthogonality in the serving cell of the NTN, transmissions from different wireless devices in a cell/beam (e.g., the first wireless device and the second wireless device in FIG. 17B) may need to be time-aligned at the base station and/or the NTN node (e.g., satellite). The cell may be the serving cell. In an example, time align ment/synch ron ization may be achieved by using different timing advance (TA) values at different wireless devices to compensate for their different propagation delays (or RTDs). As shown in FIG. 17B, for UL transmissions, the first wireless device may use the first TA value (e.g., TA_1 ) and the second wireless device may use the second TA value (TAJ).

[0311] For example, the wireless device (e.g., the first wireless device or the second wireless device) may estimate/determine/measure a (current or a latest) TA value based on the at least one NTN-config. In one case, during communication via the first cell, the wireless device may estimate/determine/measure a (current or a latest) TA value based on the first NTN-config. In other case, during communication via the first cell, the wireless device may estimate/determine/measure a (current or a latest) TA value based on the second NTN-config.

[0312] For example, the wireless device may calcu late/measure/mai ntain the current (or latest available) TA (value) of the wireless device T_TA (e.g., corresponding to a TAG ID or a primary TAG or a secondary TAG) based on at least a combination of a closed-loop TA value (or a closed-loop TA procedure/control) and/or an open-loop TA value (or an open-loop TA procedure/control). In an example, a combination of the closed-loop TA control and the open-loop TA control may be based on adding/summing the open-loop TA value (e.g., derived/calculated based on the open-loop TA procedure/control) and the closed-loop TA value (or a portion of the closed-loop TA procedure/control). The current TA value of the first wireless device may be TA_1 and the current TA value of the second wireless device may be TA . The closed-loop TA procedure/control may be based on receiving at least one (absolute) TA command (TAO) MAC CE indicating a TA value (e.g., T_A corresponding to the TAG ID, e.g., the primary TAG or the secondary TAG) from the base station (e.g., via Msg2 1312 and/or MsgB 1332 and/or a PDSCH). The TA value may indicate an adjustment of the closed-loop TA value (e.g., N_TA).

[0313] For example, a timing advance command (e.g., the TAG MAC CE) of the at least one TA command may be a TA command of a random access response. The TA command may be an absolute timing advance command MAC CE. The TA command may indicate a value T_A for a TAG T_A = 0, 1, 2, .... 3846. The wireless device may determine an amount of the time alignment for the TAG with SCS of 2^ ■ 15 kHz based on N_TA = T_A ■ 16 ■ 64/2¹¹. N_TA may be relative to the SCS of the first uplink transmission from the wireless device after the reception of the random access response or the absolute timing advance command MAC CE.

[0314] In another example, a timing advance command (e.g., the TAG MAC CE), T_A, for a TAG indicates adjustment of a current N_TA value, N_{TA old}, to the new N_TA value, N_{TA new}, by index values of T_A = 0, 1 , 2,..., 63, where for a [0315] The open-loop TA procedure/control may require a GNSS-acquired position (or location information or GNSS measurements or a GNSS fix) of the wireless device and/or the NTN-config of the serving cell (e.g. , the at least one NTN-config). The wireless device may, based on an implemented orbital predictor/propagator model (e.g., the GNSS- acquired position comprising GNSS measurements) and/or the NTN-config of the serving cell, may use the ephemeris data (and/or the GNSS-acquired position) to measure/calculate/maintain movement pattern of the satellite (corresponding to the NTN-config of the serving cell), measure/determine/estimate a service link delay (e.g., RTT of the service link), and/or measure/determine/estimate a feeder link delay (e.g., RTT of the feeder link) and/or measure/determine/estimate propagation delay between the wireless device and the base station (e.g., UE-gNB RTT of the serving cell). For example, the wireless device may, based on the GNSS-acquired position and/or the NTN-config of the serving cell, adjust the current TA value (e.g., the TA of the wireless device) via the open-loop TA procedure/control. The open-loop TA procedure/control may comprise determination/estimation calculation of one or more values, e.g., N^_adj and/or N^^m _ad°ⁿ. In some implementations, the wireless device may determine the open-loop TA value (corresponding to the serving cell) by summing up/adding the N^^m _adj^On and Ny _adj.

[0316] The wireless device may (to determine the TA value of the wireless device) based on the propagation delay of the service link (e.g., between the wireless device and the NTN node). The wireless device may determine/measure/estimate Ny _adj based on the location information of the wireless device (e.g., position and/or GNSS of the wireless device) and the satellite ephemeris data (e.g., the NTN-config) of the serving cell.

[0317] The wireless device may (to determine the TA value of the wireless device) determine/estimate N^^m _ad°ⁿ may be a common delay of the cell (e.g., a portion of the feeder link delay that is not pre-compensated by the base station). The wireless device may determine the N^^m _ad°ⁿ based on the one or more common TA parameters (e.g., the NTN- config) of the serving cell.

[0318] The wireless device may use the NTN-config of a cell (e.g., the serving cell) the calculate/determinate/measurement/maintain an estimate of the UE-gNB RTT between the UE and a base station of the cell. In an example, the wireless device may calculate/measure/estimate the UE-gNB RTT (in ms or number of slots) of the serving cell based on the current TA value and the K-Mac (if indicated by the NTN-config of the serving cell). For example, the UE-gNB RTT may be the summation of the current TA value and K-Mac (based on subcarrier spacing of the 15 KHz). When the K-Mac is 0, the wireless device may determine/measure the UE-gNB RTT based on the current TA value (of the wireless device), e.g., the UE-gNB RTT is equal to the current TA value. The wireless device may m ain tain/calcu late/update the open-loop TA value (or the UE-gNB RTT) over a validity duration of the NTN- config (e.g., T430 timer).

[0319] For example, upon or in response to acquiring/receiving the NTN-config (e.g., the at least one NTN-config) of the serving cell, the wireless device may start/restart a validity (or validation) duration/timer/window/period (e.g., T430 timer) of the serving cell. The wireless device may receive the NTN-config of the serving cell based on/upon reception of the SIB19 and/or upon reception of RRCReconfiguration message (of the one or more messages) for a target cell including reconfiguration WithSync and/or upon conditional reconfiguration execution, e.g., when applying a stored RRCReconfiguration message for the target cell including reconfiguration WithSync.

[0320] The wireless device may start a validity timer (e.g., the validity duration) based the epoch time indicated by the NTN-config of the serving cell, e.g., the wireless device may start the validity timer from/after a subframe indicated by the epoch time. The wireless device may set an initial value of the T430 timer by ntn-UISyncValidity Duration of the NTN-config of the serving cell. The wireless device may stop the validity timer of the serving cell (e.g., a source cell or first cell) upon triggering initiating the handover or the satellite switch. For example, the wireless device may stop the validity duration upon reception of the RRCReconfiguration message for the target cell (e.g., a second cell and/or a target serving cell) including reconfiguration ithSync and/or upon conditional reconfiguration execution, e.g., when applying a stored RRCReconfiguration message for the target cell including reconfiguration With Sync.

[0321] In response to determining that the validity duration being expired, the wireless device may stop/suspend UL transmissions via the serving cell and flush HARQ buffers. For example, the wireless device may, in response to the expiry of the validity timer/duration, acquire the SIB19 of the serving cell to receive an update NTN assistance information 1700. The wireless device may receive an update (satellite) ephemeris data/information and/or update common TA parameters. The wireless device may, prior to expiry of the validity duration of the serving cell and to reduce interruption in UL transmissions, (re-)acquire the SIB19 in order to have valid (estimate of) the open-loop TA value of the serving cell (valid TA value).

[0322] The wireless device may, based on receiving/acquiring the SIB19, determine the UL synchronization of the serving cell being obtained/maintained. For example, in response to starting the validity duration (e.g., based on the UL synchronization of the serving cell being obtained/maintained), the wireless device may resume the UL transmissions via the serving cell.

[0323] Upon (or in response to) the expiry of the validity duration of the serving cell and when the wireless device is not able to (re-)acquire the SIB19 (of the serving cell), the wireless device may become UL unsynchronized with the base station of the serving cell, e.g., for UL communication with the base station via the serving cell.

[0324] The base station may transmit a differential Koffset MAC CE to the wireless device. The differential Koffset MAC CE may indicate a differential Koffset in a number of slots using SCS of 15 kHz. The wireless device may use the differential Koffset (indicated by the differential Koffset MAC CE) for determining transmission timing of UL signals and/or activation/deactivation time of one or more MAC CEs at the wireless device. When the differential Koffset is indicated, the wireless device may determine a UE-specific scheduling offset K_{UE offset} based on the differential Koffset (e.g., the UE-specific scheduling offset is equal to minus the differential Koffset). If the differential Koffset is not indicated, the wireless device may set K_{UE offset} = 0. For example, the wireless device may determine K_Off_Set based on the cell-specific scheduling offset (e.g., cellSpecificKoffset, e.g., K_cen_Off_Set) of the serving cell and the UE- specific scheduling offset Ku_E ,_Off_set, e.g., u_E ,_Off_set ■ [0325] The base station may transmit, to the wireless device, a DOI. The wireless device may receive the DOI during a reception occasion/time/interval (e.g., a slot/symbol). For example, the DOI may schedule/indicate/trigger a transmission of an uplink signal/channel (e.g., a PUSCH or a PUCCH or a PRACH or an SRS) to the base station via the NTN. The wireless device may transmit UL data and/or UCI and/or preamble and/or SRS resource via/based on the UL signal to the base station via/during a transmission occasion/time/interval (e.g., slot/symbol).

[0326] The DOI may trigger/schedule/indicate a transmission of the PUSCH (e.g., the UL data) and/or the PUCCH (e.g., the UCI, e.g., HARQ-ACK information). The wireless device may use the cell-specific scheduling offset and/or the UE-specific scheduling offset to determine the transmission occasion of the PUSCH/PUCCH. For example, the

2^PUSCH transmission occasion of the PUSCH may be based on K_offset • n_Koffset, wherein K_offset = K_{cell offset} - K_{UE offset} (corresponding to the serving cell). |i_PUSCH is the SCS configuration of the PUSCH transmission and fi_Koffset is the SCS configuration of the Koffset (e.g., kHz or FR1). For example, the transmission occasion of the

2^PUCCH

PUCCH may be based on K_offset • ii_Koffset (corresponding to the serving cell) where |i_PUCCH is the SCS configuration of the PUCCH transmission. The wireless device may apply/use the current TA value (e.g., based on the closed-loop TA value and/or the open-loop TA value) of the wireless device (corresponding to the serving cell) to transmit the PUSCH/PUCCH.

[0327] In another example, for a TAG MAC CE received on uplink slot n, the wireless device may apply/adjust an uplink transmission timing (e.g., for transmission of UL signals) from a beginning/start of uplink slot n + k + 1+2¹¹ ■ Koffset time duration in msec of N_t symbols corresponding to a PDSCH processing time for UE processing capability 1 when additional PDSCH DM-RS is configured, N_T2 is a time duration in msec of N₂ symbols corresponding to a PUSCH preparation time for UE processing capability 1 , N_{TA max} is a maximum timing advance value in msec that can be provided by a TA command field of 12 bits, N^_o ^b _t ^frame,k j_s the number of slots per subframe, T_sf is the subframe duration of 1 msec. N_t and N₂ are determined with respect to the minimum SCS among the SCSs of all configured UL BWPs for all uplink carriers in the TAG and of all configured DL BWPs for the corresponding downlink carriers. For |i = 0, the UE assumes N₁₀ = 14. Slot n and N®₁ ^u _o ^bframe,k _are determined with respect to the minimum SCS among the SCSs of all configured UL BWPs for all uplink carriers in the TAG. N_TAmax is determined with respect to the minimum SCS among the SCSs of all configured UL BWPs for all uplink carriers in the TAG and for all configured initial UL BWPs provided by initial UplinkBWP. The uplink slot n may be a last/final/ending/latest slot among uplink slot(s) overlapping with the slot(s) of PDSCH reception assuming T_TA = 0, where the PDSCH provides the timing advance command.

[0328] For example, the DCI may trigger/indicate/order a transmission of the PRACH (e.g., the UL signal may be the ordered PRACH) corresponding to a preamble index. For example, the DCI (e.g., a PDCCH order) may comprise a random access preamble index field indicating a value (e.g., that is not zero) of the preamble index. For the PRACH transmission (e.g., during/via the transmission occasion) to the base station by the wireless device, triggered by the PDCCH order, a PRACH mask index field of the DOI may indicate the PRACH occasion for the PRACH transmission. In an example, the PRACH occasions may be associated with an SS/PBCH block (e.g., SSB) index indicated by the SS/PBCH block index field of the DOI (e.g., the PDCCH order). The wireless device may use the cell-specific scheduling offset (e.g., K_{cell offset} by cellSpecificKoffset) corresponding to the serving cell to determine the PRACH occasion. For example, the wireless device may determine the PRACH occasion being after slot n + 2^ ■ K_{cell offset}. n may be the slot of an UL BWP for the PRACH transmission that overlaps with an end of the PDCCH order reception (e.g., assuming TA being 0, e.g., T_TA = 0). p may be the SCS configuration for the PRACH transmission. The PDCCH order reception may be received during the reception occasion.

[0329] In response to a PRACH transmission (e.g., for performing a 2-step/4-step CFRA/CBRA procedure, e.g., for initial access and/or for beam failure recovery) by a wireless device to the base station (e.g., via the serving cell of the NTN), the wireless device may attempt to detect a DCI format 1_0 with CRC scrambled by a corresponding RA-RNTI during a RAR window (e.g., ra-ResponseWindow). The PRACH transmission may be indicated by a PDCCH order and/or higher layers (e.g., MAC/RRC layer) of the wireless device. The RAR window may start at a first/initial/earliest symbol of an earliest CORESET the wireless device is configured to receive PDCCH for Typel -PDCCH CSS set. For example, the earliest CORESET may be at least one symbol, after the last/final/end ing symbol of a PRACH occasion corresponding to the PRACH transmission. The symbol duration may correspond to an SCS for Typel -PDCCH CSS set.

[0330] When communicating with the NTN (e.g., when adj ^or is ⁿ°t ^zer°. ^e . when the open-loop TA value of the wireless device is not zero), the RAR window (e.g., ra-ResponseWindow or msgB-ResponseWindow) may start after an additional UE-gNB RTT of the serving cell. The wireless device may determine the UE-gNB RTT (e.g., in ms or in number of slots) of the serving cell based on the current TA value (e.g., T_TA) (of the serving cell) and/or the K- mac indicated by the NTN-config of the serving cell. The length of the RAR window in number of slots may be based on the SCS for Typel -PDCCH CSS set and is provided/indicated by the one or more configuration parameters (e.g., ra- ResponseWindow).

[0331] In response to a transmission of a PRACH and a PUSCH (e.g., for performing a 2-step CFRA/CBRA procedure, e.g., for initial access and/or for beam failure recovery) by the wireless device to the base station (e.g., via the serving cell of the NTN), or to a transmission of only a PRACH if the PRACH preamble is mapped to a valid PUSCH occasion, the wireless device may attempt to detect a DCI format 1_0 with CRC scrambled by a corresponding MsgB- RNTI during a RAR window (e.g., msgB-ResponseWindow). The PRACH transmission may be indicated by a PDCCH order and/or higher layers (e.g., MAC/RRC layer) of the wireless device. The RAR window may start at a first/initial/earliest symbol of an earliest CORESET the wireless device is configured to receive PDCCH for Typel - PDCCH CSS set. For example, the earliest CORESET may be at least one symbol, after the last/final/end in g symbol of a PUSCH occasion corresponding to the PRACH transmission. The symbol duration may correspond to an SCS for Typel -PDCCH CSS set. When communicating with the NTN (e.g., when or N^^m _ad°ⁿ is not zero, e.g., when the open-loop TA value of the wireless device is not zero), the RAR window may start after an additional UE-gNB RTT of the serving cell. The wireless device may determine the UE-gNB RTT (e.g., in ms or in number of slots) of the serving cell based on the current TA value (e.g., T_TA) of the serving cell and/or the K-mac indicated by the NTN-config of the serving cell. The length of the RAR window in number of slots may be based on the SOS for Typel-PDCCH CSS set and is provided/indicated by the one or more configuration parameters (e.g., msgB-ResponseWindow).

[0332] With reference to slots for a PUSCH transmission (e.g., via the serving cell of the NTN) scheduled by a RAR UL grant, if a UE receives a PDSCH with a RAR message ending in slot n for a corresponding PRACH transmission from the base station, the wireless device may transmit the PUSCH in slot n + k₂ + A + 2^ ■ K_{cell offset}, where the k₂ and A are provided by NR specification (e.g., TS 38.214) and K_{cell offset} is indicated by cellSpecificKoffset of the serving cell; otherwise, if not provided, K_{cell offset} = 0.

[0333] FIG. 18A shows an example of configured grant (CG) configuration. The one or more configuration parameters may comprise one or more CG configuration parameters. FIG. 18A only shows several parameters/entries of the one or more CG configuration parameters. FIG. 18B shows an example of CG PUSCH resources and CG PUSCH transmissions per an aspect of an embodiment of the present disclosure.

[0334] There may be two types of transmission without dynamic grant (e.g., with CG grant): a configured grant Type 1 (a CG type 1) and a configured grant Type 2 (a CG type 2). An RRC message (e.g., RRC configuration message or an RRC reconfiguration message) of the one or more RRC messages may configure/indicate the CG type 1. The wireless device may store the CG type 1 as a configured uplink grant for PUSCH transmissions with CG grant.

[0335] As shown in FIG. 18B, an RRC message (e.g., RRC configuration message or an RRC reconfiguration message) of the one or more RRC messages may configure/indicate the CG type 2. The configured uplink grant may be provided/indicated by a PDCCH (or a DCI). The wireless device may store as configured uplink grant the CG type 2 based on a L1 signalling (e.g., the DCI) indicating configured uplink grant activation. The wireless device may clear as configured uplink grant the CG type 2 based on a L1 signalling (e.g., the DCI) indicating configured uplink grant deactivation.

[0336] For example, the CG 1 ype 1 and/or the CG type 2 are configured by the one or more CG configuration parameters for a Serving Cell per BWP. For the wireless device, multiple (or plurality of) CG configurations (of Type 1 CG configuration and/or Type 2 CG configuration) may be active simultaneously in the same BWP. For Type 2, activation and deactivation are independent among the Serving Cells. For the same BWP, the MAC entity can be configured with both Type 1 and Type 2. A CG configuration of the plurality of CG configurations may be a CG-SDT configuration for small data transmissions.

[0337] For example, a CG configuration of the multiple CG configurations may be a multi-PUSCH configured grant. The multi-PUSCH configured grant may comprise of a multiple (or plurality of) consecutive configured uplink grants within a first periodicity. Both Type 1 CG configuration and Type 2 CG configuration may be configured for the multi- PUSCH configured grant by the one or more CG configuration parameters.

[0338] The one or more CG configuration parameters may comprise at least one of the following: a cs-RNTI indicating a CS-RNTI for retransmission(s) or activation or deactivation; and/or a cg-SDT-CS-RNTI indicating a CS- RNTI for CG-SDT retransmission(s); and/or a cg-SDT-RSRP-ThresholdSSB indicating an RSRP threshold configured for SSB selection for CG-SDT; and/or a rach-less-RSRP-ThresholdSSB indicating an RSRP threshold configured for SSB selection for a RACH-less handover; and/or the first periodicity indicating the periodicity of the configured grant Type 1 (or Type 2); and/or a time domain offset (e.g., a timeDomainOffset) indicating an offset (or timing gap or time gap or distance or period) of a resource (of the CG configuration) with respect to a first reference SFN in time domain; and/or a timeDomainAllocation indicating allocation of configured uplink grant in time domain which contains startSymbolAndLength (e.g., SLIV) or startSymbol (e.g., S); and/or a nrofHARQ-Processes indicating a number of HARQ processes for configured grant; and/or a harq-ProclD-Offset indicating a first HARQ offset of HARQ process for configured grant configured with cg-RetransmissionTimer for operation with shared spectrum channel access; and/or a harq-ProclD-Offset2 indicating a second HARQ offset of HARQ process for configured grant not configured with cg- RetransmissionTimer; and/or the first reference SFN (e.g., timeReferenceSFN) indicating an SFN (number) used for determination of a first offset of a resource (of the CG configuration) in time domain; and/or a second reference SFN (e.g., timeReferenceH-SFN) indicating a hyper SFN (H-SFN) number used for determination of the first offset of a resource (of the CG configuration) in time domain; and/or nrofSIotsinCG-Period indicating a number of configured uplink grants in the first periodicity of a multi-PUSCH configured grant.

[0339] As shown in FIG. 18B, the wireless device may receive the RRC message (of the one or more RRC messages) indicating/configuring a CG configuration. The RRC message may comprise the one or more CG configuration parameters. The CG configuration may indicate/configure at least one CG uplink grant for CG PUSCH transmissions. For example, upon configuration of the CG configuration (e.g., configured grant Type 1) fora BWP of a Serving Cell by the RRC (e.g., receiving the RRC message), the wireless device may store the corresponding uplink grant provided by the CG configuration for the indicated BWP of the Serving Cell.

[0340] In one example, the at least one CG UP grant may comprise the multi-PUSCH configured grant within/during the first periodicity (of the CG configuration).

[0341] In another example, the at least one CG UP grant may comprise a configured grant within/during the first periodicity (of the CG configuration).

[0342] In response to at least one reference SFN not being indicated/configured by (or being absent from) the one or more CG configuration parameters, the wireless device may determine CG PUSCH occasions (CGOs) of the CG configuration based on SFN=0 and the first offset. The first offset may be the time domain offset. For example, an initial/starting/earliest CGO (e.g., resource of the CG configuration) may be the first offset after the S FN=0. [0343] In response to a reference SFN (e.g. , the first reference SFN or the second reference SFN) being indicated/configured by (or not being absent from) the one or more CG configuration parameters, the wireless device may determine CG PUSCH occasions (CGOs) of the CG configuration based on the reference SFN and the first offset. For example, an in itial/starting/earliest CGO (e.g., resource of the CG configuration) may be the first offset after the reference SFN. The wireless device may use a closest SFN with the indicated reference SFN preceding the reception of the RRC message (indicating the configured grant configuration)

[0344] The at least one reference SFN may be/comprise the first SFN (e.g., 512).

[0345] The at least one reference SFN may be/comprise the second SFN.

[0346] The wireless device may initialise or re-initialise the configured UL grant to start in a symbol according to/based on the first offset. For example, the wireless device may initialise or re-initialise the configured UL grant to start in the symbol after the time domain offset (timeDomainOffset) from the reference SFN (timeReferenceSFN). The symbol may be based on the SLIV and/or the startSymbol by the one or more CG configuration parameters. As shown in FIG. 18B, the symbol may occur/reoccur with the first periodicity. The symbol may be an initial/starting/earliest/first symbol of a CGO within the first periodicity.

[0347] For an uplink grant of the configured grant Type 1 , the wireless device may determine the symbol within/during the N^th (N > 0) first periodicity based on the reference SFN, the time domain offset, SFN, and the like. For example, the symbol during the N^th (N > 0) first periodicity may occur/reoccur when at least one of the following equations (e.g., the first equation or the second equation) is met/fulfilled:

[0348] The first equation:

[0349] [(SFN x numberOfSIotsPerFrame * numberOfSymbolsPerSlot)

+ (slot number in the frame x numberOfSymbolsPerSlot) + symbol number in the slot] =(timeReferenceSFN x numberOfSIotsPerFrame x numberOfSymbolsPerSlot

+ timeDomainOffset x numberOfSymbolsPerSlot + S + N x periodicity) modulo (1024 x numberOfSIotsPerFrame * numberOfSymbolsPerSlot)

[0350] The second equation:

[0351] [(H-SFN x numberOfSFNperH-SFN + SFN) x numberOfSIotsPerFrame * numberOfSymbolsPerSlot + (slot number in the frame x numberOfSymbolsPerSlot) + symbol number in the slot] = timeReferenceH-

SFN x numberOfSFNperH-SFN + timeReferenceSFN) x numberOfSIotsPerFrame x numberOfSymbolsPerSlot

+ timeDomainOffset x numberOfSymbolsPerSlot + S + N x periodicity) modulo (1024 x 1024 x numberOfSIotsPerFrame * numberOfSymbolsPerSlot)

[0352] For an uplink grant of the configured grant Type 2, the wireless device may determine the symbol within/during the N^th (N > 0) first periodicity based on the reference SFN, the time domain offset, SFN, and the like. For example, the symbol during the N^th (N > 0) first periodicity may occur/reoccur when a third equation is met/fulfilled: [0353] The third equation:

[0354] [(SFN x numberOfSIotsPerFrame x numberOfSymbolsPerSlot)

+ (slot number in the frame x numberOfSymbolsPerSlot) + symbol number in the slot] =[(SFN_start numberOfSIotsPerFrame x numberOfSymbolsPerSlot

+ slotstart numberOfSymbolsPerSlot + symbolstart N x periodicity] modulo (1024 x numberOfSIotsPerFrame * numberOfSymbolsPerSlot) [0355] SFNstart slotstart and symbolstart are a first SFN, a first slot, and a first symbol, respectively, of the first/earliest/starting/in itial transmission opportunity of the corresponding CG PUSCH after the configured uplink grant is (re-)initialised.

[0356] The wireless device may transmit the CG PUSCHs using/via the CGOs within each the first periodicity (e.g., during the N^th (N > 0) first periodicity). The wireless device may transmit the CG PUSCHs during the symbol within the first periodicity (e.g., during the N^th (N > 0) first periodicity). For the multi-PUSCH configured grant Type 1 , the M^th (1 < M < nrofSIotsInCG-Period) configured uplink grant within the N^th (N > 0) first periodicity occurs (M-1) x numberOfSymbolsPerSlot symbols after the symbol in which the first configured uplink grant in the N^th (N > 0) first periodicity occurs.

[0357] The first/earliest/starting CG PUSCH transmission of the CG configuration may be after the reception of the RRC message configuring/indicating the CG configuration and/or activation of the CG configuration.

[0358] FIG. 19A and FIG. 19B show examples of handover (HO) procedures from a source gNB to a target gNB for a wireless device. FIG. 19B shows an example of a RACH-less handover procedure. FIG. 19B shows an example of a RACH-based handover procedure.

[0359] The one or more messages may comprise an RRC reconfiguration messages (e.g., RRCReconfiguration). The RRC reconfiguration message may be an RRC connection reconfiguration message. The RRC reconfiguration messages may comprise reconfiguration WithSync (in NR specifications, e.g., 3GPP 38.331) or mobilityControlInfo in LTE specifications (e.g., 3GPP 36.331). The SCell(s) may be changed using the RRC connection reconfiguration message either with or without the reconfigu ration WithSync or mobilityControlInfo. For example, the base station may transmit the RRC reconfiguration messages to the wireless device (or each wireless device of a plurality of wireless devices) in a source cell to indicate a handover (HO) to a target/neighbor cell. In an example, for/via a network- controlled mobility procedure (e.g., the HO procedure) in an RRC_CONNECTED state of the wireless device, the source cell (e.g., PCell) may be changed using the RRC connection reconfiguration message. In this specification, a HO triggered by receiving the RRC reconfiguration message (e.g., RRCReconfiguration) comprising the HO command/message (e.g., by including reconfiguration WithSync (in NR specifications) or mobilityControlInfo in LTE specifications (handover)) may be referred to as a normal HO, an unconditional HO, which is contrast with a conditional HO (OHO). [0360] As shown in FIG. 19A and/or FIG. 19B, the network (e.g., the base station) may configure the wireless device to perform measurement reporting (possibly including the configuration of measurement gaps). The measurement reporting may be a layer 3 reporting, different from layer 1 CSI reporting. The wireless device may transmit one or more measurement reports to the source base station (or a source PCell). In an example, the network may initiate HO blindly, for example without having received measurement reports from the wireless device. Before sending the HO message to the wireless device, the source base station may prepare candidate target cells. The source base station may select a candidate target cell (e.g., a candidate target POell) of the candidate target cells.

[0361] The RRC reconfiguration message (e.g., RRCReconfigu ration-IEs) may indicate information for measurement configuration, mobility control, radio resource configuration (including RBs, MAC main configuration and physical channel configuration) and AS security configuration. The RRC reconfiguration message may comprise a configuration of a master cell group (masterCellGroup). The master cell group may be associated with a SpCell (SpCellConfig).

[0362] When the SpCellConfig comprises a reconfiguration with Sync (reconfigurationWithSync), the wireless device determines that the SpCell is a target PCell for the HO. The reconfiguration with sync (reconfigurationWithSync) may comprise cell common parameters (spCellConfigCommon) of the target PCell, a RNTI (newUE-ldentity) identifying the wireless device in the target PCell, a value of the HO timer (e.g., T304), dedicated RACH resources (rach- ConfigDedicated), etc.

[0363] For example, the one or more configuration parameters may comprise one or more RACH configuration parameters, the one or more RACH configuration parameters may comprise/configure/indicate the dedicated RACH resources.

[0364] For example, based on the one or more measurement reports from the wireless device, the source base station/cell (e.g., a source gNB) may provide the target base station/cell (e.g., a target gNB) with a list of best cells (e.g., the candidate target cells) on each frequency for which measurement information is available, for example, in order of decreasing RSRP values. The source gNB may also include available measurement information for the candidate target cells (e.g., provided in the list of the best cells). The target gNB may decide which cells are configured for use after the HO, which may include cells other than the ones indicated by the source gNB. In an example, the source gNB may transmit a HO request to the target gNB. The target gNB may response with a HO message. In an example, in the HO message, the target gNB may indicate access stratum configuration to be used in the target cell(s) for the wireless device.

[0365] In an example, the source gNB may transparently (for example, does not alter values/content) forward the HO message/information (e.g., the RRC reconfiguration message) received from the target gNB to the wireless device. The HO message may configure/indicate RACH resource(s) for the wireless device to access (e.g., for initiating an RA) a cell in the target gNB. For example, the one or more configuration parameters comprise one or more RA configuration parameters and/or one or more CG configuration parameters. [0366] The one or more RA configuration parameters may comprise the RACH resource(s) for performing the handover (e.g., RACH-based handover). The one or more CG configuration parameters may configure a CG configuration (Type 1 CG configuration) for performing the handover (e.g., RACH-less handover).

[0367] After receiving the HO message (or command), the wireless device may start/initiate/trigger the handover. The handover may comprise the reconfiguration with sync configuration. For example, the wireless device may (based on initiating the handover) start a HO timer (e.g., T304) with an initial timer value. The HO message may configure the HO timer (e.g., the HO message may indicate the initial timer value of the HO timer). Based on the HO message, the wireless device may apply the RRC parameters of the target PCell and/or a cell group (MCG/SCG) associated with the target PCell of the target g N B .

[0368] For example, the wireless device may, for the initiated/triggered handover, perform (or obtain) downlink synchronization to the target gNB. Performing downlink synchronization to the target gNB may comprise searching a suitable/detectable SSB(s) from candidate SSBs configured on the target gNB.

[0369] After or in response to performing downlink synchronization (e.g., searching a suitable/detectable SSB from candidate SSBs configured on the target gNB) to the target gNB, the wireless device may obtain/perform UL synchronization.

[0370] For a RACH-based handover (see FIG. 19A), performing the UL synchronization may comprise initiating/triggering/performing a random access (e.g., contention-free, or contention-based, based on examples of FIG. 13A, FIG. 13B and/or FIG. 13C) procedure. Based on the RA procedure, the wireless device may access the target gNB and/or perform the UL synchronization to the target cell. For example, the wireless device may perform the RA procedure (e.g., a 4-step RA procedure or a 2-step RA procedure) via the RA resources configured/indicated by the HO message.

[0371] The RA resources may provide/indicate available RACH occasions according to a RACH resource selection. The RACH configuration may indicate dedicated preambles. The RACH resource(s) may comprise dedicated RACH resource(s). The dedicated RACH resource(s) may indicate the dedicated preambles.

[0372] In an example, the wireless device may activate the uplink BWP configured with firstActiveUplinkBWP-id and the downlink BWP configured with firstActiveDownlinkBWP-id on the target PCell upon performing HO to the target PCell.

[0373] Performing UL synchronization may comprise transmitting a preamble (of the dedicated preambles) via an active uplink BWP (e.g., a BWP configured as fi rstActiveUplin kB WP-id) of uplink BWPs of the target cell (e.g., the target PCell), monitoring PDCCH on an active downlink BWP (e.g., a BWP configured as firstActiveDownlinkBWP-id) for receiving a RAR (e.g., comprising a TA value for transmission of UL signals, e.g., PUSCH/PUCCH, via the target cell) via the target cell. For example, the wireless device may receive the RAR from the target base station and obtain the TA of the target cell. The wireless device, by using the TA of the target cell, adjusts uplink transmission timing for transmitting PUSCH/PUCCH via the target cell. The adjusting uplink transmission timing may comprise advancing or delay the transmissions (in the UL frame) by an amount indicated by a value of the TA of the target cell, e.g. , to ensure the uplink signals received at the target base station are aligned (in time domain) with uplink signals transmitted from other wireless devices in the target cell.

[0374] In an example, the wireless device may, in response to performing UL synchronization or successfully completing the RA procedure in the target cell, release RRC configuration parameters of the source cell and an MCG/SOG associated with the source cell.

[0375] As shown in FIG. 19A, the wireless device may transmit the preamble (e.g., PRACH) to the target g N B via a RACH resource/occasion of the PRACH resources. The RACH resource may be selected from the RACH resources (e.g., configured in rach-ConfigDedicated IE of the HO command) based on SSBs/CSI-RSs measurements (during the DL synchronization of the target cell) of the target gNB. The wireless device may select a (best) SSB/CSI-RS of the configured SSBs/CSI-RSs of the target gNB. The wireless device may select an SSB/CSI-RS, from the configured SSBs/CSI-RSs of the target gNB, with a RSRP value greater than a RSRP threshold configured for the RA procedure. The wireless device may determine a RACH occasion (e.g., time domain resources, etc.) associated with the selected SSB/CSI-RS and determine the preamble associated with the selected SSB/CSI-RS.

[0376] The target gNB may receive the preamble transmitted from the wireless device. The target gNB may transmit at least one RAR to the wireless device. The RAR may correspond to the preamble transmitted by the wireless device. An RAR (of the at least one RAR) may further comprise a TAG MAC CE (e.g., for indicating the TA value of the target cell) to be used for uplink transmission via the target cell. In response to receiving the RAR corresponding to (or comprising) the preamble transmitted by the wireless device on/via the target cell, the wireless device may (successfully) complete the random access procedure. In response to (successfully) completing the random access procedure, the wireless device may stop the HO timer (T304). The wireless device may, after completing the random access procedure, transmit an RRC reconfiguration complete message to the target gNB. In some implementations, wireless device may, before completing the random access procedure, transmit the RRC reconfiguration complete message to the target gNB.

[0377] The wireless device, after completing the random access procedure towards the target gNB, may apply first parts of CQI reporting configuration, SR configuration and/or SRS configuration that do not require the wireless device to know a system frame number (SFN) of the target gNB. The wireless device, after completing the random access procedure towards the target PCell, may apply second parts of measurement and radio resource configuration that require the wireless device to know the SFN of the target gNB (e.g., measurement gaps, periodic CQI reporting, SR configuration, SRS configuration), upon acquiring the SFN of the target gNB (e.g., performing the DL synchronization to the target cell).

[0378] FIG. 19B shows an example of RACH-less handover procedure. The wireless device may switch/handover from the source cell (e.g., via which the RRC reconfiguration message is received) to the target cell, e.g., without performing the RA procedure (e.g., without triggering/initiating the RA procedure and/or without transmitting a preamble on the target cell). The one or more configuration parameters (e.g., the HO message) may comprise RACH-less configurations (e.g., rach-skip IE and/or rach-skipSCG IE and/or ntn-rach-lessHO IE and/or rach-lessHO IE and/or rach-less IE) for skipping/avoiding RACH.

[0379] Based on the one or more configuration parameters comprising the RACH-less configurations, the wireless device may perform the HO without triggering/initiating (or performing the RA procedure. Based on the one or more configuration parameters not comprising the RACH-less configurations, the wireless device may perform the HO by triggering/initiating (or performing the RA procedure).

[0380] In some implementations, the HO command may indicate a target TA value corresponding to the target cell allowing the wireless device to acquire UL synchronization of the target cell (e.g., without initiating the RA procedure for the handover). Based on the HO command comprising the target TA value, the wireless device may perform the RACH-less handover. The wireless device may apply the target TA value of the target cell for the transmission of the initial (or first) PUSCH transmission on/via the target cell. The initial PUSCH transmission may be an initial uplink transmission of the RACH-less handover procedure. The initial uplink transmission may be for transmitting the RRC reconfiguration complete message via the target cell (e.g., during the handover procedure).

[0381] The initial PUSCH transmission may be based on a pre-allocated UL grant (uIGrantConfig and/or cg-NTN- RACH-less-Configuration or the like) or a dynamic UL grant. The one or more CG configuration parameters may configured/indicate the pre-allocated UL grant. The pre-allocated UL grant may be a configured UL grant of the CG configuration. The initial PUSCH transmission may be for transmission of the RRC reconfiguration complete message on/via the target cell. Based on the rach-LessHO being configured and the pre-allocated UL grant (e.g., uIGrantConfig being configured, the wireless device may use/select the pre-allocated UL grant for an initial (or a first) uplink transmission (e.g., an initial/first PUSCH transmission). The wireless device may perform/transmit (during the handover and/or via the second cell) the initial uplink transmission using the pre-allocated UL grant.

[0382] FIG. 18B may also show an example of the initial PUSCH transmission (during the RACH-less handover) based on the pre-allocated UL grant.

[0383] In some implementations, the HO command may not comprise the configured UL grant(s) for the transmission of the RRC reconfiguration complete message on/via the target cell. Based on the rach-LessHO being configured and the pre-allocated UL grant (e.g., uIGrantConfig not being configured, the wireless device may start monitoring the PDCCH for receiving a dynamic UL grant(s) from/via the target cell. For example, the target cell may transmit one or more DCIs indicating the dynamic UL grant(s) for the initial PUSCH transmission. In response to receiving a DCI indicating the dynamic UL grants via the target cell, the wireless device may transmit/perform the initial uplink transmission via/using the indicated dynamic uplink grant. The rach-LessHO may further indicate the beam information (or SSB or a reference signal or a TCI state, e.g., tsi-State/D) for monitoring the PDCCH and/or transmitting the initial PUSCH. [0384] The pre-allocated uplink grant may occur/reoccur with the N-th first periodicity of the CG configuration. In the rest of the preset disclosure, the “pre-configured UL grant” and/or “configured UL grant” and/or “pre-allocated UL grant” and/or “UL grant” may be used interchangeably.

[0385] For example, during the ongoing RACH-less handover procedure the wireless device may, after the transmission of the initial PUSCH transmission via/on the target cell, receive a first DOI of the one or more DOIs. The first DOI may indicate/provide a downlink assignment. The first DOI may be addressed to (scrambled with) C-RNTI of the wireless device. The first DOI may indicate/schedule a new UL/DL transmission via the target cell. In some cases, the first DOI may indicate a first HARQ process number. The first HARQ process number may correspond to the transmission of the initial PUSCH transmission. In an example, based on the first DOI, the wireless device may determine the RACH-less handover being successfully completed.

[0386] FIG. 20 shows an example embodiment of a conditional handover (CHO) procedure. The network (e.g., a base station, a source gNB) may configure the wireless device (e.g., via the one or more configuration parameters) to perform measurement reporting (possibly including the configuration of measurement gaps) for a plurality of neighbor/candidate cells (e.g., cells from a candidate target gNB 1 , a candidate target gNB 2, etc.). The measurement reporting may be a layer 3 reporting, different from a layer 1 CSI reporting. The wireless device may transmit one or more measurement reports to the source gNB (or source PCell).

[0387] As shown in FIG. 20, based on the one or more measurement reports from the wireless device, the source gNB may provide the target gNB with a list of best/candidate cells on each frequency for which measurement information is available, for example, in order of decreasing RSRP. The source gNB may also include available measurement information for the cells provided in the list. The target gNB may decide which cells are configured for use after the CHO, which may include cells other than the ones indicated by the source gNB. In an example, the source gNB may transmit a HO request to the target gNB. The target gNB may response with a HO message. In an example, in the HO message, the target gNB may indicate access stratum configuration (e.g., RRC configurations of the target cells) to be used in the target cell(s) for the wireless device. In an example, the source gNB may transparently (for example, does not alter values/content) forward the handover (e.g., contained in RRC reconfiguration messages of the target gNB) message/information received from the target gNB to the wireless device.

[0388] In an example, the source gNB may configure a CHO procedure different from a normal HO procedure (e.g., as shown in FIG. 19A and/or FIG. 19B), by comprising a conditional reconfiguration message (e.g., conditional Reconfiguration IE in the RRC reconfiguration message) of the one or more messages. The conditional reconfiguration message may be the handover message. The conditional reconfiguration message may comprise a list of candidate target cells (e.g., PCells).

[0389] A candidate target cell may be associated with the dedicated RACH resource(s) for the RA procedure in case a CHO is executed to/toward/based on the candidate target cell of the candidate cells. In response to triggering/initiating the CHO, the wireless device may initiate the RA procedure for performing the handover. For example, the handover may be a combination of the RACH-based handover and the CHO handover.

[0390] A candidate target cell may be associated with the RACH-less configuration for the initial PUSCH transmission in case a CHO is executed to/toward/based on the candidate target cell of the candidate cells. In response to triggering/initiating the CHO, the wireless device may transmit the initial PUSCH transmission (based on the dynamic UL grant or the pre-allocated UL grant) for performing the handover. For example, the handover may be a combination of the RACH-less handover and the CHO handover.

[0391] The conditional reconfiguration message may comprise CHO configurations. The CHO configurations may configure at least one CHO execution condition (or at least one CHO condition or at least one RRC reconfiguration condition or at least one CHO triggering condition). For example, a CHO execution condition of the at least one HO execution condition may correspond to a candidate target cell of the candidate target cells. The CHO execution condition may be an execution condition that needs to be fulfilled in order to trigger the rach-less/rach-based handover. In response to the at least one CHO execution condition being satisfied, the wireless device may trigger/initiate the CHO handover the rach-less/rach-based handover.

[0392] In an example, a CHO execution condition of the at least one CHO execution condition may comprise at least one of the following: a measurement event D1 (e.g., condEventDI ) for a candidate cell; and/or a measurement event T1 (e.g., condEventTI) for a candidate cell; and/or a measurement event A3 (e.g., condEventA3) for a candidate cell; and/or a measurement event A4 (e.g., condEventA4) for a candidate cell; and/or a measurement event A5 (e.g., condEventA5) for a candidate cell.

[0393] For example, a first CHO execution condition (e.g., the measurement event T1) of the at least one CHO execution condition may be a time-based (or a time-dependent) event for triggering/executing the (conditional) handover. In some cases, a second CHO execution condition of the at least one CHO execution condition may be a distance-based (or a distance-dependent) event for triggering/executing the (conditional) handover. The time-based event and/or the distance-based event may be based on the NTN assistance information.

[0394] The CHO configurations may comprise configuration parameters of a CHO procedure. In response to receiving the conditional reconfiguration message, the wireless device may evaluate the at least one CHO execution condition for the list of candidate target cells and/or the current/source cell. The wireless device may measure RSRP/RSRG of SSBs/CSI-RSs of each candidate target cell of the list of candidate target cell. Different from the normal HO procedure described in FIG. 19A and FIG.19B, the wireless device may not execute the HO toward the target cell, e.g., in response to receiving the RRC reconfiguration messages comprising the parameters of the CHO procedure.

[0395] The wireless device may, for performing the CHO procedure, execute the HO to a target cell for the CHO only when the at least one CHO execution condition of the target cell are met (or satisfied). Otherwise, the wireless device may keep evaluating the at least one CHO execution condition for the list of the candidate target cells, e.g. , until an expiry of a HO timer, or receiving a RRC reconfiguration indicating an abort of the CHO procedure.

[0396] In the example of FIG. 20, in response to a CHO execution condition (of the at least one CHO condition), e.g., of a first candidate target cell (e.g., PCell 1), being met or satisfied, the wireless device may execute the CHO procedure towards the first candidate target cell. In response to the CHO execution not being met or satisfied, the wireless device may avoid/skip executing the CHO procedure towards the first candidate target cell.

[0397] Executing (or initiating/triggering/performing) the CHO procedure may comprise initiating/triggering the RACH- less handover procedure.

[0398] Executing (or initiating/triggering/performing) the CHO procedure may comprise initiating/triggering the RACH- based handover procedure.

[0399] Executing (or initiating/triggering/performing) the CHO procedure may comprise initiating/triggering an LTM cell switch procedure.

[0400] By performing the RACH-based handover/RACH-less handover the wireless device may reset MAC.

[0401] By executing the CHO procedure, the wireless device may release the RRC configuration parameters of the source cell and the MCG associated with the source cell, apply the RRC configuration parameters of the PCell 1 , reset MAC, perform cell group configuration for the received MCG comprised in the RRC reconfiguration message of the PCell 1, and/or perform RA procedure to the PCell 1, etc.

[0402] In an example, the MCG of the RRC reconfiguration message of the PCell 1 may be associated with a SpCell (SpCellConfig) on the target g N B 1. When the sPCel IConfig comprises a reconfiguration with Sync (reconfiguration ithSync), the wireless device determines that the SpCell is a target PCell (PCell 1) for the HO. The reconfiguration with sync (reconfigurationWithSync) may comprise cell common parameters (spCellConfigCommon) of the target PCell, a RNTI (newUE-ldentity) identifying the wireless device in the target PCell, a value of T304, a dedicated RACH resource (rach-ConfigDedicated), etc. In an example, a dedicated RACH resource may comprise one or more RACH occasions, one or more SSBs, one or more CSI-RSs, one or more RA preamble indexes, etc. In an example, the wireless device may perform cell group configuration for the received master cell group comprised in the RRC reconfiguration message of the PCell 1 on the target gNB 1.

[0403] In some embodiments, the handover procedure may comprise a layer 1/2 triggered HO (or mobility) procedure, e.g., the LTM cell switch procedure. The HO command may be (or comprise) a LTM Cell Switch Command MAC CE. For example, based on the HO command indicating a TA value (e.g., an index index value TA used to control the amount of timing adjustment during/after the handover procedure), the wireless device may determine the handover procedure being the RACH-less handover.

[0404] The TA value may be a targetTA value/parameter indicated by the RACH-less configurations.

[0405] The wireless device may use the TA value for the initial PUSCH transmission for the RACH-less handover. [0406] The wireless device, after receiving an HO command (e.g., RRC reconfiguration with a ReconfigurationWithSync IE), performs downlink synchronization and uplink synchronization, beam alignment/management via a target cell and/or an early TA acquisition scheme. For example, the handover procedure may comprise/be an early TA acquisition (or ETA)-based HO procedure. The one or more configuration parameters may configure/enable the wireless device to perform the ETA for the handover procedure (e.g., the layer 1/2-triggered mobility). For example, when a Itm-UE-MeasuredTA-ID of a candidate cell (e.g., the target cell) and a Itm-UE- MeasuredTA-ID of the serving cell (e.g., the source cell) have same value, the wireless device may estimate a timing advance to apply from (or for) a first transmission (e.g., the initial uplink transmission) on/via the candidate cell that is after the reception of a cell switch command (e.g., the handover message or the LTM cell switch MAC CE) for the candidate cell. Estimating the timing advance may be based on the NTN assistance information (e.g., the second/third NTN-config).

[0407] In some embodiments, the handover procedure may comprise a feeder link switch/switchover or a satellite switch procedure in an NTN. The source (first) cell and/or the target (second) cell may be quasi-earth-fixed cells. In some other cases, the source cell and/or the target cell may be earth-moving cells. The HO procedure may correspond for a (hard or soft) service/feeder link switching/switchover procedure.

[0408] In some cases, the HO procedure may correspond to at least one of the following scenarios: an intra-satellite handover with the same feeder link (i.e., with same NTN gateway/base station or without NTN gateway/base station switch); or an intra-satellite handover with different feeder links (i.e., with NTN gateway/base station switch); or intersatellite handover with the NTN gateway/base station switch; or inter-satellite handover without the NTN gateway/base station switch.

[0409] The wireless device may, prior to performing the HO procedure (e.g., receiving the HO command via the source cell), communicate (transmit/receive) with the source base station (e.g., of the source cell) via the non-terrestrial network (NTN). The wireless device and the source base station may operate in the NTN and/or the source base station may be an NTN base station and/or the source cell (e.g., a source serving cell) may be part of the NTN.

[0410] The wireless device may, after/during the performing the HO procedure, communicate (transmit/receive) with the target base station (e.g., of the target cell) via the non-terrestrial network (NTN). The wireless device and the target base station may operate in the NTN and/or the target base station may be an NTN base station and/or the target cell (e.g., a source serving cell) may be part of the NTN. The target call may be a candidate cell.

[0411] A serving cell (e.g., the first/source cell and/or the second/targeted/candidate cell) may have a (unique) cell ID/identification/index (e.g., physical cell ID, PCI). The source cell may correspond to a first PCI (e.g., PC1 1) and the target cell may correspond to a second PCI (e.g., PCI 2).

[0412] In some embodiment, the PCI of the source cell (e.g., the first PCI, e.g., PC1 1) and the PCI of the target cell (e.g., the second PCI, e.g., PCI 2) may (depending on NW configuration) be different (e.g., a PCI changed scenario or a PCI changed HO procedure) or be the same (e.g., PCI unchanged scenario, e.g., a PCI unchanged HO procedure). [0413] In one example, based on the HO procedure being ongoing (or being started or being completed), the cell ID/identification/index of the serving cell may not change (or may stay fixed), e.g., the satellite switch with resync. The source cell and the target cell may have the same PCI, e.g., the PCI unchanged (or fixed) scenario (or scheme or case or protocol or method).

[0414] In another example, the source cell and the target cell may have different PCIs (e.g., PC1 1 corresponding to the source cell and PCI 2 corresponding to the target cell may not be equal), e.g., the PCI changed scenario.

[0415] For example, the wireless device may communicate via the first NTN node with the source base station. The first NTN node may have (or be associated with) a unique identification number. The first NTN node may correspond to a first ephemeris data/information (e.g., provided by the first NTN-config).

[0416] The wireless device may, by performing the HO procedure, communicate with a target base station (e.g., of the target cell or a second cell) via the non-terrestrial network (NTN), e.g., the wireless device and the target base station may operate in the NTN and/or the target base station may be an NTN base station and/or the target cell (e.g., a target serving cell) may be part of the NTN. The wireless device may, for example, switch from the first NTN node to the second NTN node for communicating with the target cell (or the target base station).

[0417] In some scenarios of the HO procedure, the second NTN node may be different than the first NTN node. For example, the second NTN node may have (or be associated with) a unique identification number that is different than the identification number of the first NTN node. The second NTN node may correspond to a second ephemeris data/information (e.g., provided by the second/third NTN-config).

[0418] In some implementations of the HO procedure, the source base station and the target base station may be a same base station (e.g., connecting to the first NTN node and/or the second NTN node via a same NTN gateway), e.g., the intra-satellite handover with the same feeder link. In other implementations of the HO procedure, the source base station and the target base station may not be a same base station (e.g., the source base station is connecting to the first NTN node via a first NTN gateway and/or the target base station is connecting to the second NTN node via a second NTN gateway), e.g., an intra-satellite handover with different feeder links and/or inter-satellite handover with NTN gateway/base station switch.

[0419] The wireless device may communicate (transmit/receive) with the source base station (and/or a source NTN Gateway) on the serving cell (e.g., the first cell) of the NTN. For example, the communication (or connection) between the wireless device and the source base station (and/or the source NTN Gateway) may be via an NTN node/payload (e.g., the first NTN node or the second NTN node) of the NTN. The communication between the NTN node and the source NTN Gateway is through/via a first feeder link. The source NTN Gateway may be associated (or correspond to or communicate with) the source base station and/or the first feeder link.

[0420] The feeder link switchover procedure (e.g., a feeder link switching procedure) may be ongoing/started (e.g., by/at the NTN node), e.g., in order to change the feeder link from the first feeder link to a second feeder link. For example, based on the feeder link switchover, the NTN node may switch from the source NTN Gateway to a target NTN Gateway (and/or from the source base station to the target base station). The second feeder link may be associated with the target Gateway/base station. By performing/terminating the feeder link switchover, the wireless device’s communication with the target base station (and/or the target NTN Gateway) is through the NTN node and the second feeder link (e.g. , the NTN node connects to the target NTN Gateway and/or the target base station).

[0421] For a hard feeder link switchover (compared to a soft feeder link switchover), the NTN node connects to only one NTN Gateway at any given time, i.e., a radio link interruption may occur during the transition between the feeder links (e.g., during the feeder link switchover procedure). For example, for the hard feeder link switchover, the NTN node only connects to the source NTN Gateway prior to starting the feeder link switchover and after fin ish in g/performin g the (hard) feeder link switchover, the NTN node only connects to the target NTN gateway. The radio link interruption time/window/duration may correspond for a duration/window for performing the (hard) feeder link switchover at the NTN node (and/or the network side).

[0422] Under/based on the soft feeder link switchover procedure, the wireless device may simultaneously communicate with both the source base station (e.g., on/via a source serving cell, e.g., the source cell), e.g., and the target base station (e.g., on/via the target serving cell, e.g., the target cell), e.g., during the soft feeder link switchover procedure (being ongoing).

[0423] The service link switchover procedure (e.g., a service link switching procedure) may be for changing the service link from the first service link to a second service link. For example, based on the service link switchover (e.g., the HO procedure), the wireless device may switch from the first NTN node to the second NTN node. For example, the second NTN node may connect to the source NTN Gateway. In one example, the second service link may be associated with the Gateway/base station. In another example, the second service link may be associated with the second/target Gateway/base station. For a hard service link switchover (compared to a soft service link switchover), the wireless device may connect to only one NTN node (e.g., the first NTN node or the second NTN node) at any given time, i.e., a radio link interruption may occur during the transition between the service links (e.g., during the service link switchover procedure).

[0424] Under/based on the soft service link switchover procedure, the wireless device may simultaneously communicate with both the first NTN node (e.g., via the first cell) and the second NTN node (e.g., via the second cell). [0425] FIG. 21A shows an example of initial PUSCH transmission in a handover when the RACH-less configuration indicates the pre-allocated UL grant. For example, the handover procedure may be the RACH-less handover procedure as described above in relation to FIG. 19B. The wireless device may initiate the RACH-less handover procedure based on the HO message reception and/or the at least one CHO execution condition being satisfied.

[0426] The one or more CG configuration parameters (e.g., the HO message), e.g., CbnfiguredGrantConfig, may indicate/configure the wireless device to perform/transmit the initial PUSCH transmission in the RACH-less handover. The one or more CG configuration parameters may configure the CG configuration for the configured grant Type 1 PUSCH transmissions using the pre-allocated UL grants on the initial UL BWP. [0427] The one or more configuration parameters (e.g., the RACH-less configurations) may configure/indicate a first set of SSBs (corresponding to the target cell) via ntn-SSB-Subset. The first set of SSBs (e.g., a first set of SS/PBCH blocks) may indicate a first number of SS/PBCH block indexes NpuscH™ ^maP ^{a num}ber of valid PUSCH occasions of the CG configuration. The valid PUSCH occasions may be for CG PUSCH transmissions over/during the first association period. In some examples (e.g., if one or more configuration parameters does not provide the ntn-SSB- Subset), the wireless device may determine NpuscH™ f^{rom a va}l^ue °f ssb-Positionsln Burst in ServingCellConfigCommon. A (valid) PUSCH occasion for the CG PUSCH transmissions may be a CGO of the CG configuration. The PUSCH occasion may comprise a time resource and a frequency resource. The PUSCH occasion may be associated with a DM-RS provided by cg-DMRS-Configuration in the RACH-less configurations. The valid PUSCH occasion may occur within/during UL (or flexible) symbols. The valid PUSCH occasion may correspond to an SSB with an RSRP larger/greaterthan a configured RSRP threshold.

[0428] As shown in FIG. 21A, a first association pattern period may comprise a plurality of first association periods. The plurality of first association periods may comprise one or more first association periods. Each first association period of the plurality of first association periods may correspond to the first periodicity of the CG configuration. The wireless device may determine the first association pattern period based on the PUSCH occasions of the CG configuration (configuring the pre-allocated UL grant) and/or the first set of SSBs. For example, the wireless device may determine the first association pattern period based on the first periodicity. Although FIG. 21 A shows only one first association pattern period, the first association pattern period may reoccur in time domain consecutively/repeatedly. [0429] The first association pattern period may provide a first pattern between the PUSCH occasions (of the CG configuration) with associated DMRS resources (configured/indicated by the RACH-less configurations) and the first set of SSBs (e.g., the first number of SS/PBCH block indexes). For example, the first association pattern period may repeat at most every 640 msec. The wireless device may not use one or more PUSCH occasions for PUSCH transmissions when the one or more PUSCH occasions and associated DMRS resources are not associated with a SSB of the first set of SSBs after an integer number of the first association periods.

[0430] A starting/earliest/in itial (in time domain) of the first association period of the plurality of first association periods may start from a frame with SFN 0. The first association period may be a configured PUSCH resource association period. The first association period may comprise a plurality of the first periodicities (e.g., a plurality of the PUSCH configuration periods). The first association period may be for mapping the first set of SSBs ( A/pyg^^CH SS/PBCH block indexes from the first number of SS/PBCH block indexes) to the valid PUSCH occasions and associated DM-RS resources. The wireless device may determine the first association period based on the first periodicity. The first periodicity may correspond to the CG configuration. For example, the first association period may comprise L1 >1 PUSCH configuration periods. Each PUSCH configuration period may be (equal to) the first periodicity. For example, the wireless device may determine the first association period such that the first set of SSBs SS/PBCH block indexes) being mapped at least once to the valid PUSCH occasions and associated DM-RS resources within the first association period.

[0431] The RACH-less configurations (e.g., ntn-SSB-PerCG-PUSCH may configure/indicate the first number of SS/PBCH block indexes associated with a PUSCH occasion (of the PUSCH occasions of the CG configuration) and a DM-RS resource by.

[0432] As shown in FIG. 21A, the wireless device may transmit the initial PUSCH transmission vis a CG PUSCH occasion. Using the first association period the wireless device may determine an SSB of the first set of SSBs that is mapped to the CG PUSCH occasion. The wireless device may determine beam/power for the transmission of the initial PUSCH transmission based on the determined SSB.

[0433] FIG. 21 B shows an example PRACH transmission in handover. For example, the handover procedure may be the RACH-based handover procedure as described above in relation with FIG. 19A. The wireless device may determine the handover message does not comprise the RACH-less configurations. The wireless device may initiate the RACH-based handover procedure based on the HO message reception and/or the at least one CHO execution condition being satisfied.

[0434] The HO message may indicate/configure the dedicated RACH resources (rach-ConfigDedicated). For example, the HO message may not configure/indicate the RACH-less configurations. The dedicated RACH resources may comprise one or more PRACH occasions, a second set of SSBs (corresponding to the target cell), one or more CSI-RSs (corresponding to the target cell), one or more (dedicated or contention free) RA preamble indexes, the second periodicity. The second periodicity (in ms) may indicate a PRACH configuration period of the dedicated RACH resources. The PRACH configuration period may be 10 ms or 20 ms or 40 ms or 80 ms or 160 ms.

[0435] The second set of SSBs may be the first set of SSBs.

[0436] The second set of SSBs may comprise the first set of SSBs. For example, the first set of SSBs may belong to the second set of SSBs.

[0437] The one or more configuration parameters (e.g., ssb-PositionsInBurst in SIB1 or in ServingCellConfigCommon) may indicate/configure the second set of SSBs. The one or more configuration parameters (e.g., ssb-perRACH-OccasionAndCB-PreamblesPerSSB) may indicate that a third number N of SS/PBCH block indexes of the second set of SSBs are associated with one PRACH occasion of the one or more PRACH occasions.

[0438] The second set of SSBs (e.g., a second set of SS/PBCH blocks) may indicate a second number of SS/PBCH block indexes AZ-p to map to a second number of PRACH occasions of the one or more PRACH occasions.

[0439] The second number of SS/PBCH block indexes AZ^f ^B may be the third number N of SS/PBCH block indexes. [0440] The second number of SS/PBCH block indexes AZ^f ^B may be smaller than the third number N of SS/PBCH block indexes.

[0441] As shown in FIG. 21 B, a second association pattern period may comprise a plurality of second association periods. The second association patter period may reoccur in time domain consecutively, although only one the second association patter period is shown in FIG. 21 B. The plurality of second association periods may comprise one or more second association periods. Each second association period of the plurality of second association periods may correspond to the second periodicity (e.g., the PRACH configuration period). The wireless device may determine the second association pattern period based on the one or more PRACH occasions and/or the second set of SSBs. For example, the wireless device may determine the second association pattern period based on the second periodicity. [0442] The second association pattern period may provide a second pattern between the one or more PRACH occasions and the second set of SSBs (e.g., the second number of SS/PBCH block indexes). For example, the second association pattern period may repeat at most every 160 msec. The wireless device may not use at least one PRACH occasion of the one or more PRACH occasions for preamble transmissions based on the at least one PRACH occasions not being associated with a SSB of the second set of SSBs after an integer number of the second association periods.

[0443] A starting/earliest/in itial (in time domain) of the second association period of the plurality of second association periods may start from a frame with SFN 0. The second association period may comprise a plurality of second periodicities (e.g., a plurality of the PRACH configuration periods). The second association period may be for mapping the second set of SSBs ( SS/PBCH block indexes from the second number of SS/PBCH block indexes) to at least one PRACH occasion of the one or more PRACH occasions. The wireless device may determine the second association period based on the second periodicity. The second periodicity may correspond to the dedicated RACH resources configured by the one or more RACH configuration parameters. For example, the second association period may comprise L2>1 PRACH configuration periods (e.g., L2> 1 second periodicities). Each PRACH configuration period may be (equal to) the second periodicity. For example, the wireless device may determine the second association period such that the second set of SSBs (A/^⁸ SS/PBCH block indexes) being mapped at least once to the at least one PRACH occasion within the second association period.

[0444] As shown in FIG. 21 B, the wireless device may transmit preamble vis a PRACH occasion of the one or more PRACH occasions. Using the second association period the wireless device may determine an SSB of the second set of SSBs that is mapped to the PRACH occasion. The wireless device may determine beam/power for the transmission of the preamble transmission based on the determined SSB.

[0445] In the present disclosure, “a frame #i of a cell” refers to “a radio frame i of the cell” or “a radio frame corresponding to the cell” or “a radio frame number i in the cell” or “an SFN #i in/of the cell”.

[0446] In the present disclosure, “initial PUSCH transmission for the RACH-less handover” refers to “initial uplink transmission for the RACH-less handover” or “initial transmission for the RACH-less handover”. For example, the initial transmission for the RACH-less handover may comprise an SRS transmission or a PUCCH transmission via the second cell.

[0447] In the present disclosure, “the rach-LessHO (e.g., the RACH-less configuration) not configuring/indicating the pre-allocated UL grant (uIGrantConfig and/or cg-NTN-RACH-less-Configuration ’’ refers to “the rach-LessHO (e.g., the RACH-less configuration) indicating/configuring the beam information for monitoring PDCCH indicating the transmission of the initial uplink transmission” and/or “the rach-LessHO (e.g., the RACH-less configuration) indicating/configuring the beam information for receiving the dynamic uplink grant used for the transmission of the initial uplink transmission”. [0448] In the present disclosure, "monitoring PDCCH" refers to "monitoring PDCCH candidates" or "receiving PDCCH via monitoring PDCCH candidates" or "receiving PDCCHs in/during a CORESET" or "monitoring the PDCCH candidates using one or more search space sets".

[0449] In the present disclosure, "receiving PDCCH based on a TCI state" refers to "receiving PDCCH with the TCI state" or "receiving PDCCH using TCI state". The TCI state may be the beam information indicated by the RACH-less handover configuration.

[0450] In the present disclosure, "MAC CE" refers to "MAC CE command" or "MAC CE activation command" or "activation command".

[0451] In the present disclosure, "receiving a signal (e.g., PDSCH/PDCCH/CSI-RS) in time T" refers to " receiving the signal during/on/at/in occasion/slot/symbol T".

[0452] In the present disclosure, "occasion" refers to "slot" or "symbol" or "subframe" or "frame".

[0453] In the present disclosure, "initiating a random access on a cell (e.g., the first cell)" refers to " initiating the random access via the cell " or " initiating a random access for the cell".

[0454] In the present disclosure, "a pre-allocated UL grant" refers to "a pre-configured UL grant" or "a configured UL grant" or "pre-scheduled UL grant" or "pre-indicated UL grant".

[0455] In the present disclosure, "a pre-allocated UL grant" refers to “an UL grant based on a Type 1 configured grant configuration or a Type 2 configured grant configuration”.

[0456] In the present disclosure, "a dynamic UL grant" refers to “an UL grant scheduled/indicated/activated by a DOI or PDCCH”.

[0457] In the present disclosure, "stop" refers to "terminate" or "end" or "finish" or "cease" or "conclude" or "halt" or “expire” the like.

[0458] In the present disclosure, "start" refers to "begin" or "initiate".

[0459] In the present disclosure, “handover” refers to “reconfiguration with sync procedure” or “reconfiguration procedure” or “LTM cell switch procedure”.

[0460] In the present disclosure, "RACH-less HO procedure" refers to "an HO procedure without performing an RA procedure" or "an HO procedure using rach-skip configuration" or "an HO procedure without RACH" or “RACH-less LTM cell switch procedure”.

[0461] In the present disclosure, "an HO command" refers to an "an RRC message" or "a MAC CE" or "a DCI". For example, the HO command may be (or comprise) an LTM Cell Switch Command MAC CE. In some cases, the HO command may comprise a candidate cell TCI state activation/deactivation MAC CE.

[0462] In the present disclosure, "an HO command" refers to an "an RRC reconfiguration message". [0463] In the present disclosure, "a first cell" refers to "a source cell" or "a serving cell prior to performing an HO procedure" or “a current cell” or “a cell before handover” or “a cell before satellite switch” or “a cell before feeder link switch”.

[0464] In the present disclosure, "a second cell" refers to "a target cell" or "a candidate target cell" or "non-serving cell" or "a neighbor cell" or "a serving cell after performing an HO procedure" or “a cell after the handover” or “a cell after the satellite switch” or “a cell after the feeder link switch”.

[0465] In the present disclosure, "determine" refers to "calculate" or "measure" or "estimate" or "evaluate" or "verify" or "decide" or "select" or “derive”.

[0466] In the present disclosure, "performing the handover procedure" refers to "executing the handover procedure" and/or "initiating or starting the handover procedure" and/or " triggering the handover procedure".

[0467] In the present disclosure, "an ongoing handover procedure" refers to "the handover procedure being initiated or started" and/or "the handover procedure not being successfully or unsuccessfully completed" and/or "T304 timer being running".

[0468] In the present disclosure, "an ongoing random access (RA) procedure" refers to "the RA procedure being initiated or started" and/or "the RA procedure not being successfully or unsuccessfully completed".

[0469] In the present disclosure, “a handover procedure” refers to “a handover from a first/sou rce cell with a first PCI to a second/target cell with a second PCI” or “an RRC reconfiguration procedure” or “an MAC resetting procedure” or a “a layer 3 mobility”.

[0470] In the present disclosure, “switch” refers to “switching” or “switch over” or “switchover”.

[0471] In the present disclosure, “a handover procedure” refers to or comprises “a service link switch from a first cell with a first PCI to a second cell with a second PCI” or “a satellite switch from a first cell with a first PCI to a second cell with a second PCI” or “a feeder link switch from a first cell with a first PCI to a second cell with a second PCI”.

[0472] In the present disclosure, “a service link switch without changing PCI of a cell” refers to or comprises “a service link switch from a first NTN node of the cell to a second NTN node of the cell” or “a service link switch without handover” or “a service link switch without RRC reconfiguration” or “a service link switch without resetting MAC entity” or “a PCI unchanged procedure/scenario”.

[0473] In the present disclosure, “a service link switch without changing PCI of a cell” does not comprise “a layer 3 mobility” or “handover” or “reconfiguration procedure”.

[0474] In the present disclosure, “a service link switch” refers to “a satellite switch” or “feeder link switch” or “a soft satellite switch” or “a hard satellite switch” or “a soft feeder link switch” or “a hard feeder link switch”.

[0475] In the present disclosure, “a second satellite switch method” refers to “a service link switch without changing PCI of serving cell” or “a service link switch while maintaining PCI of the serving cell”.

[0476] In the present disclosure, “method” refers to “procedure” or “protocol” or “technique” or “system”. [0477] In the present disclosure, “release” refers to “delete” or “remove” or “discard”. For example, “releasing PUCCH/SRS” refers to “deleting/removing/discarding PUCCH/SRS configurations in an RRC layer”.

[0478] In the present disclosure, “clear” refers to “delete” or “remove” or “discard” or “set to zero”. For example, “clearing SPS assignments” refers to “deleting/discarding/removing SPS assignments in the MAC layer (without releasing SPS configuration in the RRC layer”.

[0479] In the present disclosure, “suspend” refers to “halt” or “postpone” or “delay”. For example, “suspending a procedure during a window/du ration” refers to “avoiding performing the procedure during the duration” or “halting performing the procedure during the duration” or “delay ing/postponin g performing the procedure until after the duration”.

[0480] In the present disclosure, “performing a handover” refers to “triggering the handover” or “in itiatin g/startin g the handover” or “executing the handover”.

[0481] In the present disclosure, “performing a satellite switch” refers to “triggering the satellite switch” or “initiating/starting the satellite switch” or “executing the satellite switch”.

[0482] In the present disclosure, “performing DL/UL synchronization toward an NTN node or a cell” refers to “performing DL/UL synchronization for an NTN node or a cell” or “performing DL/UL synchronization with an NTN node or a cell”.

[0483] In the present disclosure, “synchronization” refers to “resynchronization” or “UL synchronization” or “DL synchronization”.

[0484] In the present disclosure, “more than” refers to “greater than” or “larger than” or “above” or “not smaller than”. [0485] In the present disclosure, “less than” refers to “smaller than” or “below” or “not greater than”.

[0486] In the present disclosure, “the target cell” refers to “the second cell”. The target cell may be a neighbor cell or a candidate cell.

[0487] In the present disclosure, “the source cell” refers to “the current cell” or “the first cell” or “the serving cell”. [0488] FIG. 210 shows an example of handover per an aspect of an embodiment of the present disclosure. The wireless device may perform handover as discussed above in relation with FIG. 19A or FIG. 19B or FIG. 20. The handover procedure may be an inter-frequency handover or an intra-frequency handover.

[0489] The handover procedure may be the RACH-less handover procedure or the RACH-based handover procedure. As shown in FIG. 210, the wireless device may trigger/initiate the handover procedure to switch/handover from the source cell to the target cell. The handover procedure may comprise the satellite switch with synchronization procedure (e.g., with PCI unchanged). For performing the handover, the wireless device may perform a downlink synchronization procedure.

[0490] The downlink (DL) synchronization may be for the target cell/gNB and/or target satellite. The downlink synchronization may comprise acquiring/determining SFN of the target cell. The DL synchronization may comprise acquiring/receiving one or more SSBs corresponding to the target cell and/or the target satellite. [0491] The one or more SSBs may belong to the first set of SSBs and/or the second set of SSBs.

[0492] The one or more SSBs may comprise the first set of SSBs and/or the second set of SSBs. For example, the one or more SSBs may comprise a third set of SSBs corresponding to at least one neighbor cells (different than the target cell).

[0493] The wireless device may perform the DL synchronization during an interruption time between the triggering of the handover and an occasion (e.g., symbol/slot/subframe) for a first/initial transmission via the target cell/satellite. [0494] The interruption time (in ms) may comprise a search time for searching the target cell. The search time may depend on whether the target cell is known to the wireless device or not. The search time may be based on a configuration of a SMTC periodicity of the target cell/satellite. The search time may be a predefined value (e.g., 5 ms). The SMTC periodicity may be configured by the handover command/message and/or a SIB (e.g., SIB2 or SIB4 or SIB19). When the target cell is known (e.g., the SFN of the target cell/satellite is known/acquired/determined), the search time may be 0 ms. When the target cell is not known (e.g., the SFN of the target cell/satellite is not known/acquired/determined), the search time may be greater than 0 ms. During a SMTC (with the SMTC periodicity) the wireless device may measure/receive the one or more SSBs

[0495] The interruption time may comprise a tracking time. The tracking time may comprise a time for tracking and acquiring full timing information of the target cell. The tracking time may comprise receiving one or more TRS signals via the target cell/satellite. The tracking time may be equal to/based on the SMTC periodicity.

[0496] When the ongoing/initiated handover is the RACH-based handover, the first/initial transmission may be a PRACH/preamble transmission (via/using the RACH resources and/or a PRACH occasion of the one or more PRACH occasions, see, FIG. 21 B). For the ongoing rach-based handover, the interruption time may further comprise a second interruption uncertainty (or window/duration) in acquiring a first/startin g/earliest PRACH occasion (of the one or more PRACH occasions) in the target cell/satellite. For example, the second interruption uncertainty may be based on a summation of the second association period (see FIG. 24) and a predefined value (10 ms).

[0497] When the ongoing/initiated handover is the RACH-less handover, the first/initial transmission may be a PUSCH transmission (via/using a CG PUSCH resource/occasion of a CG configuration or a dynamic uplink grant). For the ongoing RACH-less handover, the interruption time may further comprise a first interruption uncertainty (or window/duration) in acquiring a first/starting/earliest CG PUSCH occasion (determined based on the CG configuration configured by the HO message) in the target cell/satellite.

[0498] In an example embodiment, the first interruption uncertainty may be based on a summation of the first association period (see FIG. 24) and a predefined value (10 ms). Based on the ongoing handover procedure being the RACH-less handover procedure, the wireless device may determine the interruption time based on the first association period. Based on the ongoing handover procedure being the RACH-based handover procedure, the wireless device may determine the interruption time based on the second association period. [0499] For example, the wireless device may determine the SFN of the target cell/satellite based on the one or more SSBs. For example, the one or more SSBs may indicate/comprise at least one MIB message. A MIB message of the at least one MIB message may correspond to the target cell. A MIB message of the at least one MIB message may correspond to a neighbor cell that is different than the target cell. Determining the SFN of the target cell may be based on acquiring/receiving the at least one MIB message. For example, the wireless device may measure/receive the one or more SSBs to determine the SFN of the target cell.

[0500] For determining the SFN of the target cell, the wireless device may decode the at least one MIB message. A MIB message of the at least one MIB message corresponding to the target cell may indicate the SFN of the target cell. To reduce complexity/processing of the wireless device for determining the SFN of the target cell, the wireless device may expect to receive/detect the MIB message corresponding to the target cell without decoding/detecting too many (e.g., 10 or 20 or the like) MIB messages.

[0501] As also shown in FIG. 210, the wireless device may expect an absolute time different (e.g., an absolute value of the time difference) between a frame #i (e.g., SFN#i) of the target cell and a frame #i of the source cell be smaller than a first predefined value.

[0502] For example, the frame #i of/in the source cell may be based on a SFN of the source cell. For example, the frame #i of/in the target cell may be based on a SFN of the target cell. For example, a time difference between the frame #i of the target cell and a frame #i of the source cell may be a first time difference. The first time difference may be first predefined value.

[0503] The first predefined value may be 153600T_s (e.g., almost 10 ms), e.g., when the second association pattern period (corresponding to the dedicated RACH resources) is not equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 4.

[0504] The first predefined value may be or 76800T_s (e.g., almost 5 ms), e.g., when the first association pattern period is equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 8.

[0505] For example, for handover purposes to the target cell in paired or unpaired spectrum where the target cell uses L_max = 4, the wireless device may assume the absolute value of the time difference (e.g., the absolute time difference) between the frame #i of the source cell (e.g., a radio frame i) and the frame #i of the target cell is less than the first predefined value (e.g., 1536007)) if the second association pattern period is not equal to 10 ms.

[0506] For example, for an inter frequency handover purposes where the source cell is either in paired or unpaired spectrum and the target cell is in unpaired spectrum and uses L_max = 8, the wireless device may assume the absolute value of the time difference between the frame #i of the source cell (e.g., a radio frame i) and the frame #i of the target cell is less than the first predefined value (e.g., 768007)).

[0507] Embodiment of FIG. 210 implies that the wireless device may expect to acquire/determine the SFN of the target cell within a first window (with a length of the first time difference or the first predefined value) around the frame #i of the source cell. The target cell and the source cell may be synchronized within the first window. When the target cell and the source cell are synchronized within the first window, the wireless device may not expect to decode/detect too many (e.g., 10 or 20 or the like) MIB messages to determine the SFN of the target cell.

[0508] In existing technologies, the efficiency of the RACH-less handover may reduce. For example, for preforming the RACH-less handover, performing the DL synchronization to the target cell/satellite may not be (power/processing) efficient or may increase the processing complexity of the wireless device. For example, when the handover message comprises both the one or more RACH configuration parameters and the RACH-less configurations, the wireless device may be unable to properly (or with acceptable processing complexity) determine the determine the SFN of the target cell. In one example, the RACH-less configurations may comprise/indicate the pre-allocated UL grant. In another example, the RACH-less configurations may not comprise/indicate the pre-allocated UL grant. For example, the wireless device may use the second association patter period to determine the SFN of the target cell. In the implementation of existing technologies, assumptions/expectations of the wireless device for determining the SFN of the target cell may be limited to a case that the wireless device is performing the RACH-based handover.

[0509] In some implementation of existing technologies, when at least one of the source cell or the target cell is/are part of the NTN, the wireless device may not be able to properly (or with acceptable processing complexity) determine the determine the SFN of the target cell. For example, due to movement of the source satellite (corresponding to the source cell) and/or the target satellite (corresponding to the target cell), the wireless device may require to decoding/receiving too many (e.g., 10 or 20 or 40 or the like) MIB messages to determine the SFN of the target cell. [0510] In some implementation of existing technologies, efficiency of the RACH-less handover may reduce as the wireless device may mistakenly use a CGO of the CG configuration for the initial PUSCH transmission, e.g., when at least one of the source cell or the target cell is/are part of the NTN and/or when the handover procedure is a combination of the RACH-less handover and the CHO handover. For example, the target cell may fail to receive the initial PUSCH transmission. This may result in delay in performing the RACH-less handover.

[0511] In some implementation of existing technologies, to transmit the initial PUSCH transmission for the ongoing RACH-less handover, the wireless device may determine whether the configured UL grant of the CG configuration being valid or not. Based on an SSB of the first set of SSBs associated with/to (or mapped to) the configured UL grant with an RSRP larger than (or above) an RSRP threshold, the wireless device may determine the configured UL grant being valid for the initial PUSCH transmission. Based on an SSB of the first set of SSBs associated with/to (or mapped to) the configured UL grant with an RSRP smaller than (or below) the RSRP threshold, the wireless device may determine the configured UL grant being invalid for the initial PUSCH transmission. For example, based on configured UL grant being valid for the initial PUSCH transmission, the wireless device may use the configured UL grant for the initial PUSCH transmission of the RACH-less handover. Based on configured UL grant being invalid for the initial PUSCH transmission, the wireless device may initiate/trigger a random access procedure for the ongoing RACH-less handover (fall back to the RACH-based handover procedure). The RACH-less configurations may indicate/configure the RSRP threshold. [0512] In existing technologies, when at least one of the source cell and the target cell is part of the NT N, the wireless device may mistakenly consider the configured UL grant being valid for the initial PUSCH transmission considering the RSRSP threshold. For example, due to movement of the first NTN node and/or the second NTN node, possibility of the target cell missing/failing the reception of the initial PUSCH transmission may increase. This may result in delay in performing the RACH-less handover.

[0513] Enhancements in the handover procedure may improve efficiency of handover procedure. Some embodiments may reduce a possibility that the target cell fails to receive the initial PUSCH transmission. Some embodiments may allow the wireless device to reduce a number of decoding/receiving MIB messages for determining the SFN of the target cell.

[0514] Embodiments of the present disclosure are related to an approach for solving the problems described above. These and other features of the present disclosure are described further below.

[0515] In an example embodiment, a wireless device may determine a serving link PDD between/corresponding to two cells (of an NTN). The wireless device may transmit, via a cell of the two cells, an UL signal/channel based on the service link PDD. In an example embodiment, the wireless device may transmit, via a cell of the two cells, the UL signal/channel during/in a transmission occasion determined based on the service link PDD. The wireless device may determine the transmission occasion based on the service link PDD.

[0516] A wireless device may determine a serving link PDD between/corresponding to two cells of the NTN, e.g. , based on the NTN assistance information. In an example embodiment, the wireless device may transmit, via a cell of the two cells, a CG-PUSCH transmission based on the service link PDD. In an example embodiment, the wireless device may transmit, via a cell of the two cells, the CG-PUSCH transmission during/in a CG PUSCH transmission occasion, of one or more CG PUSCH transmission occasions, determined based on the service link PDD.

[0517] A wireless device may receive, via the first cell of the NTN, a CG configuration indicating a configured UL grant for CG PUSCH transmissions. In an example embodiment, the wireless device may transmit, via the second cell of the NTN and using the configured UL grant, a CG-PUSCH transmission based on the service link PDD. The wireless device may determine a serving link PDD between/corresponding to the first cell and the second cell based on the first NTN-config and the second NTN-config. In an example embodiment, the wireless device may transmit, via the second cell of the NTN and using the configured UL grant, the CG-PUSCH transmission during/in a CG PUSCH transmission occasion, of one or more CG PUSCH transmission occasions of the CG configuration, determined based on the service link PDD.

[0518] A wireless device may receive, via the first cell of the NTN, a CG configuration indicating a configured UL grant for CG PUSCH transmissions and a time domain offset (e.g., the first offset). In an example embodiment, the wireless device may transmit, via the second cell of the NTN and using the configured UL grant, a CG-PUSCH transmission based on the service link PDD and the time domain offset. The wireless device may determine a serving link PDD between/corresponding to the first cell and the second cell based on the first NTN-config and the second NTN-config. In an example embodiment, the wireless device may transmit, via the second cell of the NTN and using the configured UL grant, the CG-PUSCH transmission during/in a CG PUSCH transmission occasion, of the CG configuration, determined based on the service link PDD and the time domain offset.

[0519] A wireless device may receive the RACH-less configurations for handover from the first cell to the second cell. The RACH-less configurations may configure/indicate a CG configuration indicating a configured UL grant for CG PUSCH transmissions and a time domain offset (e.g., the first offset). In an example embodiment, the wireless device may transmit, via the second cell and using the configured UL grant, the initial PUSCH transmission based on the service link PDD and the time domain offset. The wireless device may determine a serving link PDD between/corresponding to the first cell and the second cell based on the first NTN-config and the second NTN-config. In an example embodiment, the wireless device may transmit, via the second cell of and using the configured UL grant, the initial PUSCH transmission during/in a CG PUSCH transmission occasion, of the CG configuration, determined based on the service link PDD and the time domain offset.

[0520] A wireless device may receive the RACH-less configurations for handover from the first cell to the second cell. The RACH-less configurations may configure/indicate a CG configuration indicating a configured UL grant for CG PUSCH transmissions and a time domain offset (e.g., the first offset). In an example embodiment, the wireless device may transmit, via the second cell and using the configured UL grant, the initial PUSCH transmission based on a summation of the service link PDD and the time domain offset. The wireless device may add the service link PDD and the time domain offset to determine a CG PUSCH transmission occasion, of the CG configuration, for the transmission of the initial PUSCH transmission. The wireless device may transmit the initial PUSCH transmission in/during the determined CG PUSCH transmission occasion.

[0521] A wireless device may receive the handover message indicating handover from the first cell to the second cell. The handover message may comprise/configure/indicate the RACH-less configurations (for performing the RACH-less handover) and the RACH configurations (for performing an RA procedure as part of the handover). The RACH-less configurations may configure/indicate the first periodicity of the CG configuration for the initial PUSCH transmission.

The CG configuration may indicate/configure the pre-allocated (or configured) UL grant for the initial PUSCH transmission. The RACH-configurations may indicate the second periodicity of the PRACH occasions.

[0522] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations indicating the pre-allocated UL grant, the wireless device may perform the DL synchronization to the target cell/satellite based on the first association pattern period. The wireless device may determine the first association pattern period based on the first periodicity. By performing the DL synchronization to the target cell/satellite, the wireless device may determine/obtain the SFN in/of the target cell/satellite. The wireless device may transmit the initial PUSCH transmission based on the determined SFN in/of the target cell/satellite. The wireless device may determine a CG PUSCH occasion for transmission of the initial PUSCH transmission based on the determined SFN in/of the target cell/satellite. [0523] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations indicating the pre-allocated UL grant, the wireless device may perform the DL synchronization to the target cell/satellite based on the first association pattern period and the second association pattern. The wireless device may perform the DL synchronization to the target cell/satellite based on a minimum of the first association pattern period and the second association pattern. The wireless device may perform the DL synchronization to the target cell/satellite based on a maximum of the first association pattern period and the second association pattern.

[0524] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations indicating the pre-allocated UL grant, the wireless device may perform the DL synchronization to the target cell/satellite based on determining whether the first association pattern period is equal to a first value (e.g., 10 ms) or not and/or whether the second association pattern is equal to the first value or not. The wireless device may perform the DL synchronization to the target cell/satellite based on at least one of the first association pattern period and the second association pattern not being equal to the first value. The wireless device may perform the DL synchronization to the target cell/satellite based on both the first association pattern period and the second association pattern not being equal to the first value.

[0525] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations not indicating the pre-allocated UL grant, the wireless device may perform the DL synchronization to the target cell/satellite based on the second association pattern period. The wireless device may determine the second association pattern period based on the second periodicity. The wireless device may perform the DL synchronization to the target cell/satellite based on determining whether the second association pattern is equal to the first value or not. [0526] A wireless device may receive the handover message indicating handover from the first cell to the second cell. The handover message may comprise/configure/indicate the RACH-less configurations (for performing the RACH-less handover) and the RACH configurations (for performing an RA procedure as part of the handover). The RACH-less configurations may configure/indicate the first periodicity of the CG configuration for the initial PUSCH transmission. The CG configuration may indicate/configure the pre-allocated (or configured) UL grant for the initial PUSCH transmission. The RACH-configurations may indicate the second periodicity of the PRACH occasions.

[0527] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations indicating the pre-allocated UL grant, the wireless device may determine the SFN in/of the target cell/satellite based on the first association pattern period (corresponding to the CG configuration for the pre-allocated UL grant) and/or the SFN in/of the source cell. The wireless device may determine the first association pattern period based on the first periodicity. The wireless device may perform the RACH-less handover based on the SFN in/of the target cell/satellite.

[0528] A wireless device may receive the handover message indicating handover from the first cell to the second cell. The handover message may comprise/configure/indicate the RACH-less configurations (for performing the RACH-less handover) and the RACH configurations (for performing an RA procedure as part of the handover). The RACH-less configurations may configure/indicate the first periodicity of the CG configuration for the initial PUSCH transmission. The CG configuration may indicate/configure the pre-allocated (or configured) UL grant for the initial PUSCH transmission. The RACH-configurations may indicate the second periodicity of the PRACH occasions.

[0529] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations indicating the pre-allocated UL grant, the wireless device may determine the SFN in/of the target cell/satellite based on the first association pattern period (corresponding to the CG configuration for the pre-allocated UL grant) and/or the SFN in/of the source cell. The wireless device may determine the first association pattern period based on the first periodicity. The wireless device may perform the RACH-less handover based on the SFN in/of the target cell/satellite. The wireless device may transmit the initial PUSCH transmission based on the determined SFN in/of the target cell/satellite. The wireless device may determine a CG PUSCH occasion for transmission of the initial PUSCH transmission based on the determined SFN in/of the target cell/satellite.

[0530] In an example embodiment, the wireless device may, in response to the handover message, determine whether to trigger/initiate the RACH-less handover procedure or the RACH-based handover procedure based on a variation of the first service link PDD between/corresponding to the first cell (the source cell/satellite) and the second cell (the target cell/satellite).

[0531] In an example embodiment, the wireless device may, in response to the handover message, determine whether to trigger/initiate the RACH-less handover procedure or the RACH-based handover procedure based on whether the first service link PDD changed/varied above the threshold or not.

[0532] In an example embodiment, the wireless device may, in response to the handover message, determine a type of the handover (e.g., RACH-less or RACH-based) based on a variation of the first service link PDD between/corresponding to the first cell (the source cell/satellite) and the second cell (the target cell/satellite).

[0533] In an example embodiment, the wireless device may, in response to the handover message, determine whether a type of the handover is the RACH-less or the RACH-based based on whether the first service link PDD changed/varied above the threshold or not.

[0534] In an example embodiment, the wireless device may, in response to triggering/initiating the handover procedure (e.g., in response to the handover message or based on the at least one CHO execution condition being satisfied), determine a type of the handover (e.g., RACH-less or RACH-based) based on a variation of the first service link PDD between/corresponding to the first cell (the source cell/satellite) and the second cell (the target cell/satellite). [0535] In an example embodiment, the wireless device may, in response to triggering/initiating the handover procedure (e.g., in response to the handover message or based on the at least one CHO execution condition being satisfied), determine whether a type of the handover is the RACH-less or the RACH-based based on whether the first service link PDD changed/varied above the threshold or not.

[0536] For example, the wireless device may determine whether the first service link PDD changed/varied above the threshold or not. [0537] In response to the first service link PDD changed/varied above the threshold, the wireless device may determine the type of the handover procedure is the RACH-based. The wireless device may trigger/initiate the RA procedure for performing the handover. The wireless device may transmit a preamble (for the triggered RA procedure) via/suing the dedicated RACH resources.

[0538] In response to the first service link PDD changed/varied below the threshold, the wireless device may determine the type of the handover procedure is the RACH-less. The wireless device may perform the RACH-less handover procedure by transmitting the initial PUSCH transmission via the pre-allocated UL grant.

[0539] In an example embodiment, the wireless device may, in response to triggering/initiating the RACH-less handover procedure, determine whether to trigger/initiate the RA procedure based on a variation of the first service link PDD between/corresponding to the first cell (the source cell/satellite) and the second cell (the target cell/satellite). For example, the wireless device may determine whether the first service link PDD changed/varied above the threshold or not.

[0540] In response to the first service link PDD changed/varied above the threshold, the wireless device may trigger/initiate the RA procedure for performing the RACH-less handover. The wireless device may transmit a preamble (for the triggered RA procedure) via/suing the dedicated RACH resources.

[0541] In response to the first service link PDD changed/varied above the threshold, the wireless device may determine whether a reference signal (e.g., SSB) associated with the pre-allocated UL grant having an RSRP above the RSRP threshold or not.

[0542] Based on the SSB associated with the pre-allocated UL grant having the RSRP above the RSRP threshold, the wireless device may avoid triggering/initiating the RA procedure for performing the RACH-less handover. The wireless device may transmit the initial PUSCH transmission using the pre-allocated UL grant.

[0543] Based on the SSB associated with the pre-allocated UL grant having the RSRP above the RSRP threshold, the wireless device may trigger/initiate the RA procedure for performing the RACH-less handover. The wireless device may transmit a preamble (for the triggered RA procedure) via/suing the dedicated RACH resources.

[0544] Some embodiments of the present disclosure may further improve UL transmissions and/or handover for scenarios that communication of the wireless device is interrupted due to discontinuity gap/window/duration/period (or an interruption gap/window/duration/period). The discontinuity gap may be because of discontinuous coverage of an NTN node (e.g., the first NTN node or the second NTN node). The discontinuity gap may be because of the interruption gap of the feeder link switch or the service link switch. For example, the target/source satellite may comprise mechanically steering antennas/beams. For example, the wireless device may be a VSAT. The wireless device may support a mechanically steered beam/antenna. When there is the discontinuity gap in communication with the source cell/target cell (e.g., discontinuous coverage), the wireless device may (using the embodiments of the present disclosure) properly determine the occasion for the UL transmissions and/or perform the handover procedure. [0545] FIG. 22, FIG. 23, and FIG. 24 illustrate examples of RACH-less handover procedure as per an aspect of an embodiment of the present disclosure. The wireless device may perform the RACH-less handover procedure as described above in relation to FIG. 19B and/or FIG. 21A. The wireless device may perform the DL synchronization (as also described above in relation to FIG. 210) as part of the RACH-less handover procedure. The wireless device may perform the UL synchronization as part of the RACH-less handover procedure. The RACH-less handover procedure may comprise the reconfiguration with sync procedure.

[0546] As shown the wireless device may receive the handover message (e.g., at time/occasion TO) via the source cell. The handover message may comprise the reconfiguration with sync configuration parameters. The handover message may comprise the one or more RACH configuration parameters (e.g., the dedicated RACH resources) and/or the RACH-less configurations. Based on the handover message comprising the RACH-less configurations, the wireless device may initiate/trigger the RACH-less handover procedure (e.g., at time/occasion T1 ).

[0547] In one example, initiating/triggering the RACH-less handover is based on/in response to the receiving the handover message. For example, the handover message may not indicate the at least one CHO execution condition. [0548] In one example, initiating/triggering the RACH-less handover is based on/in response to the at least one CHO execution condition being satisfied. For example, the handover message may indicate the at least one CHO execution condition.

[0549] The one or more RACH configuration parameters may indicate the second periodicity (e.g., the RACH configuration period) corresponding to the one or more PRACH occasions or RACH resources. For example, the one or more configuration parameters may configure/indicate the second set of SSBs.

[0550] The RACH-less configurations may configure the CG configuration (e.g., the pre-allocated UL grant). For the ongoing RACH-less handover procedure, the wireless device may use the pre-allocated UL grant for the transmission of the initial PUSCH. The CG configuration may indicate the first periodicity (e.g., the PUSCH configuration period), the one or more configuration parameters may configure/indicate the first set of SSBs.

[0551] In an example embodiment, as shown in FIG. 22, for the RACH-less handover procedure, the wireless device may perform the DL synchronization to the target cell/satellite based on the first association pattern period. The wireless device may determine the SFN in/of the target cell/satellite based on the first association pattern period (corresponding to the CG configuration for the pre-allocated UL grant). The wireless device may determine the first association pattern period based on the first periodicity.

[0552] In response to the handover message comprising the RACH-less configurations, the wireless device may avoid performing the DL synchronization to the target cell/satellite based on the second association pattern period (corresponding to the dedicated RACH resources). In response to the handover message comprising the RACH-less configurations, the wireless device may avoid determining the SFN in/of the target cell/satellite based on the second association pattern period (corresponding to the dedicated RACH resources). In response to the handover message comprising the RACH-less configurations, the wireless device may avoid determining the second association pattern period.

[0553] As shown in FIG. 22, based on determining the SFN in/of the target cell (e.g., SFN#n), the wireless device may transmit one or more UL singles/ch an nels via the target cell. The one or more UL signals/channels may comprise the initial PUSCH transmission. For example, the wireless device may determine OGOs (e.g., CG PUSCH occasions) of the CG configuration (for transmission of the initial PUSCH) based on the determined SFN of/in the target cell.

[0554] As shown in FIG. 22, based on determining the SFN in/of the target cell (e.g., SFN#n), the wireless device may transmit one or more DL singles/ch an nels via the target cell. The one or more DL signals/channels may comprise one or more DCIs/PDCCHs/CSI-RSs/PDSCHs.

[0555] For determining the SFN of the target cell and based on the handover message comprising the RACH-less configurations, the wireless device may receive/decode a MIB message (of the at least one MIB message) based on receiving/measuring at least one SSB of the first set of SSBs. For example, the wireless device may measure/receive the one or more SSBs. The wireless device may decode/receive the at least one MIB message.

[0556] Example embodiments may enhance efficiency/perform ance of the RACH-less handover procedure. For example, the wireless device may use CG configuration indicated by the RACH-less configurations to determine the SFN in the target cell. Using the embodiments of the present disclosure, the wireless device may properly (without decoding too many MIB messages) perform the DL synchronization when performing the RACH-less handover procedure.

[0557] As also shown in FIG. 23, the wireless device may expect an absolute time difference (e.g., an absolute value of the time difference) between a frame #i of the target cell and a frame #i of the source cell be smaller than a first predefined value.

[0558] For example, the frame #i of/in the source cell may be based on a SFN of the source cell. For example, the frame #i of/in the target cell may be based on the SFN of the target cell. For example, a time difference between the frame #i of the target cell and a frame #i of the source cell may be the first time difference. The first time difference may be first predefined value.

[0559] In response to the handover message comprising the RACH-less configurations, the first predefined value may be 153600T_s (e.g., almost 10 ms), e.g., when the first association pattern period is not equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 4.

[0560] In response to the handover message comprising the RACH-less configuration and the RACH-less configurations indicating the CG configuration (the pre-allocated UL grant), the first predefined value may be 153600T_s (e.g., almost 10 ms), e.g., when the first association pattern period is not equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 4.

[0561] The first predefined value may be or 76800T_s (e.g., almost 5 ms), e.g., when the first association pattern period is equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 8. [0562] In response to the handover message comprising the RACH-less configurations, the first predefined value may be or 76800T_s (e.g., almost 5 ms), e.g., when the first association pattern period is equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 8.

[0563] In response to the handover message comprising the RACH-less configurations and the RACH-less configurations indicating the CG configuration (the pre-allocated UL grant), the first predefined value may be or 76800T_s (e.g., almost 5 ms), e.g., when the first association pattern period is equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 8.

[0564] As shown in FIG. 24, for the triggered/initiated RACH-less handover procedure, for performing the DL synchronization the wireless device may determine whether the RACH-less configurations comprise/indicate the preallocated UL grant (e.g., the CG configurations for the initial PUSCH transmission) or not. Based on the RACH-less configurations comprising/indicating the pre-allocated UL grant (e.g., the CG configurations for the initial PUSCH transmission), the wireless device may perform the DL synchronization using the first association pattern period. Based on the RACH-less configurations comprising/indicating the pre-allocated UL grant (e.g., the CG configurations for the initial PUSCH transmission), the wireless device may perform the DL synchronization without using (or ignoring) the first association pattern period and/or the second association pattern period.

[0565] In an example embodiment, for the triggered/initiated RACH-less handover procedure, for determining the SFN in/of the target cell the wireless device may determine whether the RACH-less configurations comprise/indicate the pre-allocated UL grant (e.g., the CG configurations for the initial PUSCH transmission) or not. Based on the RACH- less configurations comprising/indicating the pre-allocated UL grant (e.g., the CG configurations for the initial PUSCH transmission), the wireless device may determine the SFN in/of the target cell using the first association pattern period. Based on the RACH-less configurations comprising/indicating the pre-allocated UL grant (e.g., the CG configurations for the initial PUSCH transmission), the wireless device may determine the SFN in/of the target cell without using (or ignoring) the first association pattern period and/or the second association pattern period.

[0566] FIG. 25 and FIG. 26 show examples of uplink transmissions in an NTN per an aspect of an embodiment of the present disclosure. The wireless device may receive the NTN assistance information via the serving cell (e.g., the source cell). The wireless device may communicate with a base station via the first NTN node (e.g., the source satellite). The NTN assistance information may comprise the first NTN-config and/or the second NTN config. The second NTN-config may correspond to the second NTN node (e.g., the target satellite).

[0567] In one example, the second NTN node may correspond to the target cell. The PCI of the target cell (e.g., PCI2) may be different than the PCI of the source cell (e.g., PC11 ), e.g., service link/feeder link switch with PCI changed scenario.

[0568] In one example, the second NTN node may correspond to the source cell. The PCI of the target cell (e.g., PCI2) may be equal to the PCI of the source cell (e.g., PC11 ), e.g., service link/feeder link switch with PCI unchanged scenario. [0569] As shown in FIG. 25, the wireless device may determine at least one service link propagation delay difference (PDD) based on the NTN assistance information. The service link PDD of the at least one serving link PDD may be based on a GNSS location information (or GNSS measurement) of the wireless device.

[0570] A service link PDD of the at least one serving link PDD may correspond to the first NTN node and the second

NTN node.

[0571] A service link PDD of the at least one serving link PDD may correspond to the source cell and the target cell.

[0572] A service link PDD of the at least one serving link PDD may correspond to the source satellite and a neighbor satellite/cell.

[0573] As shown in FIG. 26, the wireless device may determine the at least one serving link PDD based on the first set of NTN configuration parameters. For example, a service link PDD of the at least one serving link PDD may be based on a first common delay parameters (of the first NTN-config) and a second common delay parameters (of the second NTN-config). For example, the service link PDD of the at least one serving link PDD may be based on a first ephemeris information (of the first NTN-config or the first NTN node) and a second ephemeris information (of the second NTN-config or the second NTN node).

[0574] In an example embodiment, as shown in FIG. 25, the wireless device may transmit at least one UL signal/channel based on the at least one service link PDD. For example, the wireless device may transmit via a transmission occasion the at least one signal/channel via. For example, the wireless device may transmit the at least one signal/channel via the target cell/second NTN node. The wireless device may determine the transmission occasion based on the at least one service link PDD.

[0575] In an example embodiment, as shown in FIG. 26, the wireless device may transmit at least one UL signal/channel based on a service link PDD of the at least one service link PDD. The wireless device may determine the transmission occasion (for transmitting the at least one UL signal/channel) based on a service link PDD of the at least one service link PDD. The wireless device may determine the service link PDD based on the first NTN-config and the second NTN-config. The wireless device may determine the transmission occasion correspond to the second cell/second NTN node. The wireless device may determine the transmission occasion is in a radio frame of the second cell (e.g., the target cell). The wireless device may determine the transmission of the at least one signal/channel being via the second NTN node. For example, the wireless device may transmit the at least one signal/channel via the second NTN node. The second NTN node may correspond to/belong to the target cell. The second NTN node may correspond to/belong to the serving cell (e.g., the source cell).

[0576] The at least one UL signal/channel may comprise a PRACH or PUSCH or SRS or PUCCH.

[0577] The at least one UL signal/channel may use periodic resource(s) (PUCCH/PRACH/SRS/PUSCH resources) or semi-persistent resource(s) (PUCCH/PRACH/SRS/PUSCH resources). For example, the one or more configuration parameters (e.g., the handover message) may configure/indicate the periodic resource(s) or the semi-persistent resource(s) for transmission of the at least one UL signal/channel. The transmission occasion may be based on the periodic resource(s) and/or the semi-persistent resource(s). When the one or more configuration parameters are received by the wireless device via the source cell/satellite and the at least one UL sign als/channels are transmitted via the target cell/satellite, the wireless device may transmit the at least one UL signal/channel based on the at least one service link PDD. This allows the wireless device to properly advance (with a positive value or a negative value) in time the periodic resource(s) or semi-persistent resource(s), wherein the positive or the negative value is based on the at least one service link PDD.

[0578] The at least one UL signal/channel may be aperiodic UL signal/channel. For example, a DL message/channel/signal indicate/schedule/trigger/activate transmission of the at least one UL signal/channel. The transmission occasion may be based on the DL message. The DL message may indicate the transmission occasion. [0579] For example, the DL message may activate/update semi-persistent resource(s) for transmission of the at least one UL signal/channel. The transmission occasion may be based on the DL message and/or the semi-persistent resource(s).

[0580] The DL message/channel/signal may be an RRC message of the one or more RRC messages or a DOI or a MAC CE. The wireless device may receive the DL message/channel/signal via the serving cell/satellite. When the DL message/signal is received by the wireless device via the source cell/satellite and the at least one UL signals/channels are transmitted via the target cell/satellite, the wireless device may transmit the at least one UL signal/channel via the transmission occasion determined based on the at least one service link PDD. This allows the wireless device to properly advance (with a positive value or a negative value) in time the semi-persistent resource(s), wherein the positive or the negative value is based on the at least one service link PDD.

[0581] FIGs. 27-32 show examples of RACH-less handover procedure per an aspect of an embodiment of the present disclosure.

[0582] In some aspects, FIGs. 27-32 may provide some example implementations of the embodiment of FIG. 25.

[0583] In some other aspects, FIGs. 27-32 may provide enhancements for the RACH-less handover procedure. The wireless device may perform the RACH-less handover as discussed above in relation to FIG. 19B and/or FIGs. 22-24B.

[0584] In some cases, the enhancements may target (or may correspond to) the NTN scenarios, e.g., when at least one of the source cell and the target cell is part of the NTN. Enhancements may allow the wireless device to properly perform the DL synchronization procedure (as part of the RACH-less handover) and/or properly determine (or adjust/update) CGOs of the CG configuration (e.g., corresponding to the pre-allocated UL grant) for the initial PUSCH transmission.

[0585] In some other cases, the enhancements may target (or may correspond to) a combination of the RACH-less handover and the CHO handover, e.g., when the triggering/initiating the RACH-less handover is based on the at least one CHO execution condition being satisfied. Enhancements may allow the wireless device to properly determine (or adjust/update) CGOs of the CG configuration (e.g., corresponding to the pre-allocated UL grant) for the initial PUSCH transmission. [0586] The wireless device may receive the NTN assistance information via the serving cell (e.g., the source cell). The wireless device may communicate with a base station via the first NTN node (e.g., the source satellite). The NTN assistance information may comprise the first NTN-config and/or the second NTN config. The second NTN-config may correspond to the second NTN node (e.g., the target satellite).

[0587] In one example, the second NTN node may correspond to the target cell. The PCI of the target cell (e.g., PCI2) may be different than the PCI of the source cell (e.g., PC11 ), e.g., service link/feeder link switch with PCI changed scenario.

[0588] In one example, the second NTN node may correspond to the source cell. The PCI of the target cell (e.g., PCI2) may be equal to the PCI of the source cell (e.g., PC11 ), e.g., service link/feeder link switch with PCI unchanged scenario.

[0589] As also discussed above in relation to FIG. 25 and/or FIG. 26, the wireless device may determine the at least one service link propagation delay difference (PDD) based on the NTN assistance information. For example, the at least one service link PDD may comprise a first service link PDD between/corresponding to the source cell/satellite and the target cell/satellite. The handover message may indicate the second NTN-confg. The SIB19 may indicate/provide the second NTN-config.

[0590] The wireless device may determine the at least one PDD at/on/during/in a first time (or time point or occasion, e.g., slot or symbol). For example, the wireless device may determine the first service link PDD at/on/in/during the first time. The first time may be during a running time/window of a handover timer (T304 timer). The first timer may be during the ongoing handover procedure.

[0591] The first time may correspond to an occasion/time that the wireless device triggers/initiate the RACH-less handover procedure.

[0592] The first time may correspond to an occasion/time that the wireless device receives the handover message via the source cell.

[0593] The first time may correspond to an occasion/time that the wireless device decodes the handover message (e.g., 10 ms after the receiving the handover message).

[0594] The first time may correspond to an occasion/time for transmission of the initial PUSCH transmission. For example, the first time may correspond to an occasion/time for an in itial/startin g/earliest OGO of the CG configuration for the initial PUSCH transmission.

[0595] In an example embodiment, in response to receiving the handover message, the wireless device may determine the at least one service link propagation delay difference (PDD). For example, the wireless device may determine the handover message comprising/indicating the RACH-less configuration. For example, the wireless device may determine the RACH-less configuration indicate/configure the pre-allocated UL grant (e.g., the CG configuration) for the initial PUSCH transmission. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) based on the at least one service link PDD. [0596] As shown in FIGs. 27-32, the wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) based on the first service link PDD. For example, the wireless device may determine the CG PUSCH occasion (corresponding to the CG configuration) for the initial PUSCH transmission based on the first service link PDD. The wireless device may determine the CG PUSCH occasion of the configured/pre-allocated UL grant based on the first service link PDD.

[0597] In an example embodiment, in response to receiving the handover message and the handover message indicating/configuring the pre-allocated UL grant (e.g., the CG configuration) for the initial PUSCH transmission, the wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the at least one service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the first service link PDD.

[0598] As shown in FIG. 28, the wireless device may trigger/initiate RACH-less handover after a first timing gap from/after the receiving the handover message. In an example embodiment, in response to triggering/initiating the RACH-less handover (e.g., based on the receiving the handover message), the wireless device may determine the at least one service link propagation delay difference (PDD). The wireless device may determine the first timing gap being greater/larger than a first threshold. For example, the wireless device may determine the handover message comprising/indicating the RACH-less configuration. The wireless device may determine the RACH-less configuration indicate/configure the pre-allocated UL grant (e.g., the CG configuration) for the initial PUSCH transmission. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the at least one service link PDD. As shown in FIG. 28, the wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the first service link PDD.

[0599] The first timing gap may be based on the interruption time/window. The first timing gap may be based on an RRC processing time/delay (e.g., 10 ms). The first timing gap may be based on an SSB processing time/delay.

[0600] The first timing gap may be based on the at least one CHO execution condition. For example, the first timing gap may be based on the time-based CHO execution condition of the at least one CHO execution condition.

[0601] The first threshold may be a predefined value (e.g., 20 ms). The one or more configuration parameters may configure/indicate the first threshold. The first threshold may be based on the cell-specific Koffset. For example, the NTN assistance information may indicate/configure the first threshold. In another example, the handover message may configure/indicate the first threshold.

[0602] The wireless device may trigger/initiate RACH-less handover based on the at least one CHO execution condition being satisfied. In an example embodiment, in response to triggering/initiating the RACH-less handover (e.g., based on the at least one CHO execution condition being satisfied), the wireless device may determine the at least one service link propagation delay difference (PDD). The wireless device may determine the at least one CHO execution condition being satisfied the first timing gap after the receiving the handover message. The wireless device may determine the first timing gap being greater/larger than a first threshold. For example, the wireless device may determine the handover message comprising/indicating the RACH-less configuration. The wireless device may determine the RACH-less configuration indicate/configure the pre-allocated UL grant (e.g., the CG configuration) for the initial PUSCH transmission. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH- less handover and via the target cell/satellite) in (or during) the CG PUSCH occasion determined based on the at least one service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the first service link PDD. [0603] In an example embodiment, in response to triggering/initiating the RACH-less handover after the first timing gap from the receiving the handover message and the handover message indicating/configuring the pre-allocated UL grant (e.g., the CG configuration) for the initial PUSCH transmission, the wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the at least one service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the first service link PDD.

[0604] In an example embodiment, in response to triggering/initiating the RACH-less handover and the first timing gap being smaller/shorter than the first threshold, the wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) without using the at least one service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite), wherein the transmission of the initial PUSCH is not based on the first service link PDD. For example, the CG PUSCH occasion for the transmission of the initial PUSCH transmission may not be determined based on the first service link PDD.

[0605] In an example embodiment, in response to triggering/initiating the RACH-less handover and the handover message not indicating/comprising the at least one CHO execution condition, the wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) without using the at least one service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH- less handover and via the target cell/satellite), wherein the transmission of the initial PUSCH is not based on the first service link PDD. For example, the CG PUSCH occasion for the transmission of the initial PUSCH transmission may not be determined based on the first service link PDD.

[0606] In some implementations, as shown in FIG. 29 and FIG. 30, the wireless device may transmit a plurality of service link PDDs via the source cell/satellite. For example, the wireless device may transmit plurality of service link PDDs via an RRC message or a MAC CE or a PUCCH. The wireless device may transmit plurality of service link PDDs via/using a PUSCH transmission. For example, the one or more configuration parameters may configure (or enable) the wireless device to report/transm it the plurality of service link PDDs. [0607] The wireless device may determine the plurality of service link PDDs based on the NTN assistance information. For example, each service link PDD may correspond to the source cell/satellite (corresponding to the first NTN-config) and a neighbor cell/satellite (corresponding to the second/third NTN-config). The wireless device may measure/determine a service link PDD corresponding to the source cell/satellite (corresponding to the first NTN-config) and the neighbor cell/satellites (corresponding to the second/third NTN-config) based on the first NTN-config and the second NTN-config.

[0608] As shown in FIG. 29 and FIG. 30, the wireless device may transmit the plurality of service link PDD before receiving the handover message.

[0609] For example, a second service link PDD of the plurality of service link PDDs may correspond to the source cell/satellite and the targe cell/satellite. The first service link PDD may measure the service link PDD between source cell/satellite and the targe cell/satellite at the first time (the first occasion). The second service link PDD may measure the service link PDD between source cell/satellite and the targe cell/satellite at a second time (a second occasion). The second time point may be prior to the first time point. For example, the wireless device may measure/determine the first service link PDD before/prior to the second service link PDD.

[0610] Due to movement of the satellites (e.g., the first NTN node and the second NTN node), the source/target base station may not be aware of the first service link PDD. The source/target base station may determine the CG configuration (for the pre-allocated UL grant) based on the second service link PDD received from the wireless device. Embodiments of the present disclosure allows the wireless device to properly use the first service link PDD (measured after the receiving the handover message) to properly u pd ate/adjust (in time domain) the pre-allocated UL grant for the initial PUSCH transmission. Embodiments may reduce possibility of the target cell failing to receive the initial PUSCH transmission.

[0611] In an example embodiment, in response to triggering/initiating the RACH-less handover, the wireless device may determine the first service link propagation delay difference (PDD) being different than the second service link PDD. For example, the wireless device may determine the second service link PDD being greater than the first service link PDD. For example, the wireless device may determine the second service link PDD being smaller than the first service link PDD. The wireless device may determine a different between the first service link PDD and the second service link PDD is greater/larger than a third threshold. In an example, the wireless device may determine the second service link PDD being changed more than the third threshold. For example, the wireless device may determine the handover message comprising/indicating the RACH-less configuration. The wireless device may determine the RACH- less configuration indicate/configure the pre-allocated UL grant (e.g., the CG configuration) for the initial PUSCH transmission. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the first service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the second service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the difference between the first service link and the second service link PDD. [0612] The third threshold may be a predefined value (e.g., 20 ms). The one or more configuration parameters may configure/indicate the third threshold. The third threshold may be based on the cell-specific Koffset. For example, the NTN assistance information may indicate/configure the third threshold. In another example, the handover message may configure/indicate the third threshold.

[0613] In an example embodiment, in response to triggering/initiating the RACH-less handover and the difference between the first service link and the second service link PDD being smaller than the third threshold, the wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) without using the first service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite), wherein the transmission of the initial PUSCH is not based on the first service link PDD. For example, the CG PUSCH occasion for the transmission of the initial PUSCH transmission may not be determined based on the first service link PDD.

[0614] As shown in FIG. 30, the wireless device may trigger/initiate RACH-less handover after a second timing gap from/after transmitting the plurality of service link PDDs via the source cell/satellite. For example, the wireless device may determine the second timing gap being greater/larger than a second threshold. In an example embodiment, in response to triggering/initiating the RACH-less handover after the second timing gap from the transmitting the plurality of service link PDD, the wireless device may determine the first service link propagation delay difference (PDD). The wireless device may determine the second timing gap being greater/larger than a second threshold. For example, the wireless device may determine the handover message comprising/indicating the RACH-less configuration. The wireless device may determine the RACH-less configuration indicate/configure the pre-allocated UL grant (e.g., the CG configuration) for the initial PUSCH transmission. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the at least one service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH- less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the first service link PDD.

[0615] The second threshold may be a predefined value (e.g., 20 ms). The one or more configuration parameters may configure/indicate the second threshold. The second threshold may be based on the cell-specific Koffset. For example, the NTN assistance information may indicate/configure the second threshold. In another example, the handover message may configure/indicate the second threshold.

[0616] In an example embodiment, in response to triggering/initiating the RACH-less handover before the second timing gap from/after transmitting the plurality of service link PDDs, the wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) without using the first service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite), wherein the transmission of the initial PUSCH is not based on the first service link PDD. For example, the CG PUSCH occasion for the transmission of the initial PUSCH transmission may not be determined based on the first service link PDD.

[0617] In the example of FIG. 31, the second time may correspond to the occasion/time that the wireless device receives the handover message. As shown in FIG. 31, the wireless device may determine the second service link PDD in response to receiving the handover message.

[0618] In an example embodiment, in response to triggering/initiating the RACH-less handover, the wireless device may determine the first service link propagation delay difference (PDD) being different than the second service link PDD. For example, the wireless device may determine the second service link PDD being greater than the first service link PDD. For example, the wireless device may determine the second service link PDD being smaller than the first service link PDD. The wireless device may determine the different between the first service link PDD and the second service link PDD is greater/larger than the third threshold. In an example, the wireless device may determine the second service link PDD being changed more than the third threshold. For example, the wireless device may determine the handover message comprising/indicating the RACH-less configuration. The wireless device may determine the RACH-less configuration indicate/configure the pre-allocated UL grant (e.g., the CG configuration) for the initial PUSCH transmission. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the first service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) based on the second service link PDD. The wireless device may transmit the initial PUSCH transmission (for the ongoing RACH-less handover and via the target cell/satellite) in the CG PUSCH occasion determined based on the difference between the first service link and the second service link PDD.

[0619] As shown in FIG. 32, when the RACH-less configurations indicate/configure the pre-allocated UL grant (e.g., the CG configuration for the initial PUSCH transmission), the wireless device may determine CG occasions (e.g., CGOs or CG PUSCH occasions) of the CG configuration based on the first service link PDD. For example, the wireless device may determine a second offset based on the first service link PDD and/or the time domain offset (e.g., the first offset) indicated corresponding to the CG configuration. The RACH-less configurations may configure/indicate the CG configuration.

[0620] The second offset may be different than the first offset. For example, the wireless device may determine the first service link PDD being different (greater or smaller) than the second service link PDD. The wireless device may determine the difference between the first service link PDD and the second service link PDD being greater/larger than a configured threshold (e.g., by the handover message).

[0621] In some cases, when the source/target base station determines the first offset (e.g., the time domain offset) based on the second service link PDD, by using the second offset for determining the CG occasions (e.g., CGOs or CG P USC H occasions) of the CG configuration, the wireless device may reduce possibility that the target base station fails to receive the initial PUSCH transmission.

[0622] The second offset may be the first offset. For example, the wireless device may determine the first service link PDD not being different (greater or smaller) than the second service link PDD. The wireless device may determine the difference between the first service link PDD and the second service link PDD being smaller than the configured threshold (e.g., by the handover message).

[0623] The pre-allocated UL grant may be an UL grant of the at least one CG uplink grant.

[0624] The CG configuration may indicate/configure the pre-allocated UL grant for the initial PUSCH transmission for the ongoing RACH-less handover.

[0625] For example, the wireless device may determine the CG configuration of the RACH-less configurations not indicating a reference SFN (of the at least one reference SFN). The reference SFN may correspond to the CG configuration. Based on the reference SFN not being configured/indicated (by the RACH-less configurations), the wireless device may determine CG PUSCH occasions (CGOs) of the CG configuration based on SFN=0 in/of the target cell/satellite and the first offset. For example, the wireless device may determine the reference SFN is absent from CG configuration of the RACH-less configurations. The second offset may be based on the time domain offset (e.g., the first offset) and the first service link PDD. For example, an in iti al/startin g/earliest CGO (e.g., resource of the CG configuration) may be the second offset after the S FN=0 in/of the target cell/satellite.

[0626] In an example embodiment, when the RACH-less configurations do not indicate the reference SFN, the wireless device may use a closest SFN in/of the target cell/satellite with the number of 0 preceding the reception of the handover message (indicating the configured grant configuration) for determining the CG PUSCH occasions (CGOs) of the CG configuration. The wireless device may transmit the initial PUSCH transmission via/using/based on at least one CG PUSCH occasion of the CG PUSCH occasions.

[0627] In an example embodiment, when the RACH-less configurations do not indicate the reference SFN, the wireless device may use a closest SFN in/of the target cell/satellite with the number of 0 preceding the triggering/initiating the RACH-less handover for determining the CG PUSCH occasions (CGOs) of the CG configuration. The wireless device may transmit the initial PUSCH transmission via/using/based on the at least one CG PUSCH occasion of the CG PUSCH occasions.

[0628] In response to the reference SFN being indicated/configured by RACH-less configurations, the wireless device may determine the CG PUSCH occasions (CGOs) of the CG configuration based on the reference SFN and the second offset. For example, an initial/startin g/earliest CGO (e.g., resource of the CG configuration) may be the second offset after the reference SFN. The wireless device may use a closest SFN in/of the target cell/satellite (e.g., S FNstart time ) with the indicated reference SFN preceding the reception of the handover message (indicating the configured grant configuration) for determining the CG PUSCH occasions (CGOs) of the CG configuration. For example, an initial/starting/earliest CGO (e.g., resource of the CG configuration) may be the second offset after the (SFN=the reference SFN) in/of the target cell/satellite.

[0629] In an example embodiment, when the RACH-less configurations indicate the reference SFN, the wireless device may use a closest SFN in/of the target cell/satellite with a number equal to the reference SFN preceding the reception of the handover message (indicating the configured grant configuration) for determining the CG PUSCH occasions (CGOs) of the CG configuration. The wireless device may transmit the initial PUSCH transmission via/using/based on the at least one CG PUSCH occasion of the CG PUSCH occasions.

[0630] In an example embodiment, when the RACH-less configurations do not indicate the reference SFN, the wireless device may use a closest SFN in/of the target cell/satellite with a number equal to the reference SFN preceding the triggering/initiating the RACH-less handover for determining the CG PUSCH occasions (CGOs) of the CG configuration. The wireless device may transmit the initial PUSCH transmission via/using/based on the at least one CG PUSCH occasion of the CG PUSCH occasions. In response to the at least one CHO execution condition being satisfied, the wireless device may trigger/initiate the RACH-less handover.

[0631] In an example embodiment, the wireless device may, based on triggering initiating the RACH-less handover, initialise or re-initialise the pre-allocated UL grant (of the CG configuration) to start in a symbol (e.g., symbolstart time) according to/based on the second offset. In response to the at least one CHO execution condition being satisfied, the wireless device may trigger/initiate the RACH-less handover. Alternatively, in response to receiving the handover message, the wireless device may trigger/initiate the RACH-less handover.

[0632] For example, the wireless device may, for the triggered/initiated RACH-less handover, initialise or re-initialise the pre-allocated UL grant to start in the symbol after the second offset from the closest SFN in/of the target cell/satellite preceding the triggering/initiating the RACH-less handover. The closest SFN in/of the target cell/satellite may have a number 0 or the reference SFN (timeReferenceSFN). The symbol may be based on the SLIV and/or the startSymbol by the CG configuration.

[0633] In an example embodiment, in response to triggering/initiating the RACH-less handover and for the preallocated UL grant, the wireless device may determine the symbol within/during the N^th (N > 0) first periodicity based on the second offset from the closest SFN in/of the target cell/satellite preceding the triggering/initiating the RACH-less handover.

[0634] In an example embodiment, in response to triggering/initiating the RACH-less handover and for the preallocated UL grant, the wireless device may determine the symbol within/during the N^th (N > 0) first periodicity based on the second offset from the closest SFN in/of the target cell/satellite preceding the receiving the handover message. [0635] For example, the symbol during the N^th (N > 0) first periodicity may occur/reoccur when at least one of the following equations (e.g., a fourth equation or a fifth equation or a sixth equation) is met/fulfilled:

[0636] The fourth equation: [0637] [(SFN x numberOfSIotsPerFrame x numberOfSymbolsPerSlot)

+ 2^nd offset x numberOfSymbolsPerSlot + S + N x periodicity) modulo (1024 x numberOfSIotsPerFrame * numberOfSymbolsPerSlot) [0638] The fifth equation:

[0639] [(H-SFN x numberOfSFNperH-SFN + SFN) x numberOfSIotsPerFrame * numberOfSymbolsPerSlot + (slot number in the frame x numberOfSymbolsPerSlot) + symbol number in the slot] =((timeReferenceH- SFN x numberOfSFNperH-SFN + timeReferenceSFN) x numberOfSIotsPerFrame x numberOfSymbolsPerSlot

+ 2^nd offset x numberOfSymbolsPerSlot + S + N x periodicity) modulo (1024 x 1024 x numberOfSIotsPerFrame * numberOfSymbolsPerSlot)

[0640] The sixth equation:

[0641] [(SFN x numberOfSIotsPerFrame * numberOfSymbolsPerSlot)

4- (slot number in the frame x numberOfSymbolsPerSlot) + symbol number in the slot] numberOfSIotsPerFrame x numberOfSymbolsPerSlot modulo (1024 x numberOfSIotsPerFrame * numberOfSymbolsPerSlot)

[0642] In an example embodiment, may correspond to a first/earliest/starting/initial CG PUSCH transmission opportunity using the pre-allocated UL grant after the triggering/initiating the RACH-less handover procedure. The may be in the radio frame of the target cell/satellite. In response to the at least one OHO execution condition being satisfied, the wireless device may trigger/initiate the RACH-less handover. Alternatively, in response to receiving the handover message, the wireless device may trigger/initiate the RACH-less handover. The may be the second offset after/from the triggering the RACH-less handover procedure. The wireless device may transmit the initial PUSCH transmission during the slotstart A starting/initial/earliest symbol of slotstart that is used for the initial PUSCH transmission may be symbolstart The wireless device may transmit the initial PUSCH transmission during the slotstart

[0643] FIGs. 33-35 show examples of handover procedure per an aspect of an embodiment of the present disclosure. Embodiments of FIGs. 33-35 may provide enhancements for the DL synchronization procedure during the handover procedure, when at least one of the source cell and/or the target cell are part of the NTN. Embodiments of FIGs. 33-35 may provide enhancements for determining the SFN in/of the target cell/satellite during the handover procedure, when at least one of the source cell and/or the target cell are part of the NTN.

[0644] In some aspects, FIGs. 33-35 may provide some example implementations of the embodiment of FIG. 25 and/or FIG. 26. [0645] The handover procedure may be the RACH-less handover procedure. In some other aspects, FIGs. 33-35 may provide enhancements for the RACH-less handover procedure. The wireless device may perform the RACH-less handover as discussed above in relation to FIG. 19B and/or FIGs. 22-24B. In some cases, the enhancements may correspond to the NTN scenarios, e.g., when at least one of the source cell and the target cell is part of the NTN. Enhancements may allow the wireless device to properly determine (or adjust/update) CGOs of the CG configuration (e.g., corresponding to the pre-allocated UL grant) for the initial PUSCH transmission. In some examples, the RACH- less handover procedure is triggered/initiated based on at least one CHO execution condition being satisfied. Embodiments of FIGs. 33-35 may provide enhancements for the DL synchronization procedure in relation to FIG. 22 and/or FIG. 23 and/or FIG. 24.

[0646] The handover procedure may be the RACH-based handover procedure. Embodiments of FIGs. 33-35 may provide enhancements for the DL synchronization procedure during the RACH-based handover procedure, when at least one of the source cell and/or the target cell are part of the NTN. Embodiments of FIGs. 33-35 may provide enhancements for determining the SFN in/of the target cell/satellite during the RACH-based handover procedure, when at least one of the source cell and/or the target cell are part of the NTN. In some examples, the RACH-based handover procedure is triggered/initiated based on at least one CHO execution condition being satisfied.

[0647] The wireless device may receive the NTN assistance information via the serving cell (e.g., the source cell). The wireless device may communicate with a base station via the first NTN node (e.g., the source satellite). The NTN assistance information may comprise the first NTN-config and/or the second NTN config. The second NTN-config may correspond to the second NTN node (e.g., the target satellite).

[0648] In one example, the second NTN node may correspond to the target cell. The PCI of the target cell (e.g., PCI2) may be different than the PCI of the source cell (e.g., PC11 ), e.g., service link/feeder link switch with PCI changed scenario.

[0649] In one example, the second NTN node may correspond to the source cell. The PCI of the target cell (e.g., PCI2) may be equal to the PCI of the source cell (e.g., PC11 ), e.g., service link/feeder link switch with PCI unchanged scenario.

[0650] As also discussed above in relation to FIG. 25 and/or FIG. 26, the wireless device may determine the at least one service link propagation delay difference (PDD) based on the NTN assistance information. For example, the at least one service link PDD may comprise the first service link PDD between/corresponding to the source cell/satellite and the target cell/satellite. The handover message may indicate the second NTN-confg. The SIB19 may indicate/provide the second NTN-config.

[0651] The wireless device may determine the at least one PDD at/on/during/in the first time (or time point or occasion, e.g., slot or symbol). For example, the wireless device may determine the first service link PDD at/on/in/during the first time. [0652] As shown in FIGs. 33-35, the wireless device may perform the DL synchronization to the target cell/satellite based on the at least one service link PDD. For example, the wireless device may perform the DL synchronization to the target cell/satellite based on the first service link PDD. In response to performing the DL synchronization to the target cell/satellite, the wireless device may transmit an UL signal (e.g., preamble or the initial PUSCH) transmission for the ongoing handover procedure. Performing the DL synchronization to the target cell/satellite may comprise determining/obtaining an SFN (e.g., SFN#i) of/in the target cell/satellite. Based on determining the SFN in/of the target cell, the wireless device may receive one or more DL sin gles/channels via the target cell. The one or more DL signals/channels may comprise one or more DCIs/PDCCHs/CSI-RSs/PDSCHs.

[0653] In an example embodiment, as shown in FIG. 33, the wireless device may determine the SFN (e.g., SFN#i) of/in the target cell/satellite based on the first service link PDD. For example, the wireless device may determine the SFN of/in the target cell/satellite based on the SFN of/in the source cell/satellite and the first service link PDD.

[0654] In an example embodiment, for the RACH-less handover procedure, the wireless device may perform the DL synchronization to the target cell/satellite based on the first association pattern period and the first service link PDD. The wireless device may determine the SFN in/of the target cell/satellite based on the first association pattern period (corresponding to the CG configuration for the pre-allocated UL grant) and the first service link PDD.

[0655] In response to the handover message not comprising the RACH-less configurations (e.g., the ongoing handover procedure is the RACH-based handover procedure), the wireless device may determine the SFN in/of the target cell/satellite based on the second association pattern period (corresponding to the dedicated RACH resources) and the first service link PDD.

[0656] As shown in FIG. 34, the wireless device may determine the SFN of/in the target cell/satellite is within a first window centered around the SFN in/of the source satellite/cell. the first window may be an SFN search window. The length of the first window may be based on the first service link PDD. The length of the first window may be based on a predefined value (e.g., 76800T_s ms or 153600T_s). The length of the first window may be based on whether the target cell uses Lmax=4 or Lmax=8. The length of the first window may be based on whether the target cell is part of the NTN or not.

[0657] Based on the handover message indicating/comprising the RACH-less configuration, the wireless device may determine the first window based on the first association patter period.

[0658] Based on the handover message not indicating/comprising the RACH-less configuration, the wireless device may determine the second window based on the first association patter period.

[0659] The wireless device may measure the one or more SSBs during the first window. The wireless device may decode/receive the at least one MIB message during the first window. The wireless device may expect to detect the MIB message corresponding to the target cell during the first window.

[0660] By using the first service link PDD the wireless device may improve efficiency of the DL synchronization procedure during the handover procedure. For example, a possibility of determining the SFN of/in the target cell during the first window may increase without increasing the processing complexity of the wireless device, e.g., without decoding too many (e.g., 10 or 20 or the like) MIB messages.

[0661] In one implementation, the wireless device may determine a first threshold based on the first service link PDD and/or the first predefined value (153600T_s). In response to the handover message comprising the RACH-less configurations, the first threshold may be based on the first predefined value and the first service link PDD. In response to the handover message comprising the RACH-less configurations and the first association pattern period not being equal to 10 ms, the first threshold may be based on the first predefined value and the first service link PDD. Based on the target cell using L_max = 4, the first threshold may be based on the first predefined value and first service link PDD. For example, the wireless device may be a summation of the first predefined value and the first service link PDD (e.g., adding the first service link PDD to the first predefined value). For example, the first threshold may determine the first threshold is based on a maximum value among the first predefined value and the first service link PDD. As shown in FIG. 33, the wireless device may expect the first time difference being smaller than the first threshold (e.g., when the target cell using L_max = 4). For example, the wireless device may determine the length of the first window being twice the first threshold (e.g., when the target cell using L_max = 4).

[0662] In another implementation, the wireless device may determine a second threshold based on the first service link PDD and/or the second predefined value (76800T_s). In response to the handover message comprising the RACH- less configurations, the second threshold may be based on the second predefined value and the first service link PDD. In response to the handover message comprising the RACH-less configurations and the first association pattern period not being equal to 10 ms, the second threshold may be based on the second predefined value and the first service link PDD. Based on the target cell using L_max = 8, the second threshold may be based on the second predefined value and first service link PDD. For example, the second threshold may be a summation of the second predefined value and the first service link PDD (e.g., adding the first service link PDD to the second predefined value). For example, the wireless device may determine the second threshold is based on a maximum value among the second predefined value and the first service link PDD. As shown in FIG. 33, the wireless device may expect the first time difference being smaller than the second threshold (e.g., when the target cell using L_max = 8). For example, the wireless device may determine the length of the first window being twice the first threshold (e.g., when the target cell using L_max = 8).

[0663] A drawback of the embodiment of FIG. 34 may be that the wireless device requires to measure the at least one MIB message during the first window. Compared to legacy systems (e.g., in terrestrial networks), the length of the first window may be varying (due to movement of the satellites). Compared to legacy systems (e.g., in terrestrial networks), the length of the first window may grow (due to movement of the satellites).

[0664] For example, the wireless device may transmit a UE capability message via the source cell (to the base station). The UE-capability message may indicate the wireless device has capability (or supports) performing the DL synchronization during the first window (with the varying length). The UE-capability message may indicate the wireless device has capability to measure/decode a maximum number of MIB messages during the first window (with the varying length). The maximum number of MIB messages may be 10 or 20 or the like.

[0665] The mentioned drawback (in relation to embodiment of FIG. 34) may be addressed (or solved) using embodiment of FIG. 35. As shown in FIG. 35, the wireless device may determine a first gap based on the first service link PDD. The first gap may be equal to the first service link PDD. As shown in FIG. 35, the wireless device may determine a frame #j (SFN#j) in/of the source cell based on a frame #i (SFN#i) in/of the source cell and the first gap. In the example of FIG. 35, the first gap is a positive value. Although FIG. 35 shown the SFN#j of/in the source cell is ahead of the SFN#i of/in the source cell (in time domain), in some cases the SFN#j of/in the source cell may be before the SFN#i of/in the source cell (in time domain), e.g. , when the first gap is a negative value.

[0666] In some implementations, the first gap may be based on an SFN offset and first service link PDD. For example, the first gap is based on a summation of the SFN offset and first service link PDD. In some cases, the first gap is equal to the SFN offset.

[0667] The one or more configuration parameters (e.g., handover message) may configure/indicate the SFN offset. The SFN offset may correspond to a difference between the SFN in/of the source cell and the SFN in/of the target cell. For example, the source base station may determine the SFN offset based on the second service link PDD.

[0668] In an example embodiment, the wireless device may, based on determining the first service link PDD being different than the second service link PDD, determine first gap is based on a summation of the SFN offset and first service link PDD. The wireless device may determine the first service link PDD being changed compared to the second service link PDD. For example, the wireless device may determine a different between the first service link PDD and the second service link PDD being greater than a threshold.

[0669] In an example embodiment, the wireless device may, based on determining the first service link PDD not being different than the second service link PDD, determine first gap is based on the SFN offset. The wireless device may determine the first service link PDD not being changed compared to the second service link PDD. For example, the wireless device may determine a different between the first service link PDD and the second service link PDD being smaller than the threshold.

[0670] In one example, the one or more configuration parameters may configure/indicate the threshold.

[0671] In another example, the threshold may be predefined.

[0672] In an example embodiment, the wireless device may determine the SFN#i (or frame #i) of/in the target cell based on the determined SFN#i of/in the source cell. As shown in FIG. 35, the wireless device may expect an absolute time different (e.g., an absolute value of the time difference) between a frame #i of the target cell and a frame #j of the source cell be smaller than the first predefined value or the second predefined value.

[0673] For example, a time difference between the frame #i of the target cell and the frame #j of the source cell may be the first time difference. The first time difference may be first predefined value or the second predefined value. [0674] In response to the handover message comprising the RACH-less configurations, the first predefined value may be 153600T_s (e.g., almost 10 ms), e.g., when the first association pattern period is not equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 4.

[0675] In response to the handover message comprising the RACH-less configuration and the RACH-less configurations indicating the CG configuration (the pre-allocated UL grant), the first predefined value may be 153600T_s (e.g., almost 10 ms), e.g., when the first association pattern period is not equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 4.

[0676] The first predefined value may be or 76800T_s (e.g., almost 5 ms), e.g., when the first association pattern period is equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 8.

[0677] In response to the handover message comprising the RACH-less configurations, the first predefined value may be or 76800T_s (e.g., almost 5 ms), e.g., when the first association pattern period is equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 8.

[0678] In response to the handover message comprising the RACH-less configurations and the RACH-less configurations indicating the CG configuration (the pre-allocated UL grant), the first predefined value may be or 76800T_s (e.g., almost 5 ms), e.g., when the first association pattern period is equal to 10 ms. The first predefined value may be 153600T_s when the target cell uses L_max = 8.

[0679] By determining the SFN#i of/in the target cell based on the SFN#j in/of the source cell, the wireless device may avoid decoding/receiving too many MIB messages (e.g., 10 or 20). For example, the wireless device may determine the S FN#i of/in the target cell with in/in a second window around the SFN#j in/of the source cell. The length of the second window may be fixed. The length of the second window may be less than or equal to the first predefined value (when the target cell uses L_max = 4). The length of the second window may be less than or equal to the second predefined value (when the target cell uses L_max = 8). The length of the second window may not be based on the first service link PDD. The length of the second window may not ch an ge/vary by the movement of the first NTN node and/or the second NTN node. Fe, the wireless device may expect receive a MIB message during the second window around the SFN#j in/of the source cell. The MIB message may indicate the SFN#i of/in the target cell.

[0680] FIGs. 36-39 show examples of RACH-less handover in an NTN scenario per an aspect of an embodiment of the present disclosure.

[0681] In some aspects, FIGs. 36-39 may provide/illustrate some example implementations of the embodiment of FIG. 25 or FIG. 26.

[0682] In some other aspects, FIGs. 36-39 may provide/illustrate one or more enhancements for the handover procedure. For example, the one or more enhancements may allow the wireless device to determine whether to trigger/initiate the RACH-less handover or the RACH-based handover, e.g., based on the at least one service link PDD. For example, the one or more enhancements may allow the wireless device to determine whether to trigger/initiate an RA procedure for the ongoing RACH-less handover, e.g., based on the at least one service link PDD. [0683] The wireless device may perform the RACH-less handover as discussed above in relation to FIG. 19B and/or FIGs. 22-24B. In some other aspects, FIGs. 36-39 may provide/illustrate one or more enhancements for the RACH-less handover procedure.

[0684] The wireless device may perform the RACH-based handover as discussed above in relation to FIG. 19A. In some other aspects, FIGs. 36-39 may provide/illustrate one or more enhancements for the RACH-based handover procedure.

[0685] In some cases, the enhancements may target (or may correspond to) the NTN scenarios, e.g., when at least one of the source cell and the target cell is part of the NTN. Enhancements may allow the wireless device to properly determine whether the configured UL grant (e.g., the pre-allocated UL grant) of the CG configuration is valid or not for the initial PUSCH transmission.

[0686] In some other cases, the enhancements may target (or may correspond to) a combination of the handover and the CHO handover, e.g., when the triggering/initiating the handover is based on the at least one CHO execution condition being satisfied.

[0687] Although not shown in FIGs. 36-39, the wireless device may receive the NTN assistance information via the serving cell (e.g., the source cell). The wireless device may communicate with a base station via the first NTN node (e.g., the source satellite). The NTN assistance information may comprise the first NTN-config and/or the second NTN config. The second NTN-config may correspond to the second NTN node (e.g., the target satellite).

[0688] In one example, the second NTN node may correspond to the target cell (or the second cell). The PCI of the target cell (e.g., PCI2) may be different than the PCI of the source cell (e.g., PC11 ), e.g., service link/feeder link switch with PCI changed scenario.

[0689] In one example, the second NTN node may correspond to the source cell. The PCI of the target cell (e.g., PCI2) may be equal to the PCI of the source cell (e.g., PC11 ), e.g., service link/feeder link switch with PCI unchanged scenario.

[0690] As also discussed above in relation to FIG. 25 and/or FIG. 26, the wireless device may determine the at least one service link propagation delay difference (PDD) based on the NTN assistance information. For example, the at least one service link PDD may comprise a first service link PDD between/corresponding to the source cell/satellite and the target cell/satellite. The handover message may indicate the second NTN-confg. The SIB19 may indicate/provide the second NTN-config.

[0691] For example, the wireless device may receive the handover message via the source cell. The handover message may configure/indicate the reconfiguration with sync procedure. The handover message may configure/indicate the satellite switch with resynchronization. The handover message may configure/comprise the RACH-less configurations and/or RACH configurations. The RACH configurations may comprise/indicate the one or more RACH configuration parameters. The RACH configurations may configure/indicate the (dedicated) RACH resources. The RACH configurations may be for performing an RA procedure as part of the ongoing handover procedure.

[0692] The wireless device may determine/measure whether the first service link PDD varies/changes compared to (or with respect to) the second service link PDD, e.g. , more than a threshold or not. For example, based on the handover message comprising the RACH-less configurations and the RACH configurations, the wireless device may determine/measure whether the first service link PDD varies/changes compared to (or with respect to) the second service link PDD. For example, based on the RACH-less configurations indicating the pre-allocated UL grant for the initial PUSCH transmission, the wireless device may determine/measure whether the first service link PDD varies/changes compared to (or with respect to) the second service link PDD. The one or more configuration parameters (e.g., the handover message or the SIB19) may indicate/configure the threshold. For example, the wireless device may determine whether the first service link PDD varies/changes compared to (or with respect to) the second service link PDD more than a threshold or not during a second window/duration.

[0693] The second duration may start from the second time (e.g., transmission of the plurality of the service link PDD). The second duration may start from the receiving the handover message. The second duration may start prior to starting/initiating the handover message. The second time may correspond to a latest available estimate of the first service link PDD prior to initiating/triggering the handover procedure. The latest available estimate of the first service link PDD may be the second service link PDD.

[0694] In an example, the wireless device may determine at/on/during/in a first time that the first service link PDD varies/changes compared to (or with respect to) the second service link PDD more than (or above) the threshold. [0695] The first time may be during a running time/window of the handover timer (T304 timer). The first timer may be during the ongoing handover procedure. The first time may be during the second duration. The first time may be a reception occasion/time/slot of the handover message. The first time may be a triggering/initiation time/occasion of the handover procedure. In one example, the wireless device may stop/expires the second window based on the first service link PDD varies/changed more than the threshold.

[0696] As shown in FIG. 36 and FIG. 37, the wireless device may (based on the handover message) trigger/initiate the RACH-less handover procedure. The wireless device may trigger/initiate the RACH-less handover procedure in response to receiving the handover message. The wireless device may trigger/initiate the RACH-less handover procedure in response to the at least one CHO execution condition being satisfied/met.

[0697] In an example embodiment, as shown in FIG. 36, based on the first service link PDD being varied/changed more than (or above) the threshold, the wireless device may determine the configured/pre-allocated UL grant (of the CG configuration) being invalid for the initial PUSCH transmission of the RACH-less handover. For example, the wireless device may determine first service link PDD being varied/changed more than (or above) the threshold compared to (or with respect to) the second service link PDD. The wireless device may determine an SSB of the first set of SSBs associated with/to (or mapped to) the configured UL grant having an RSRP larger than (or above) the RSRP threshold.

[0698] In an example embodiment, based on the first service link PDD being varied/changed more than (or above) the threshold, the wireless device may trigger/initiate the RA procedure for the ongoing handover (e.g., the ongoing RACH-less handover) procedure. The wireless device may determine an SSB of the first set of SSBs associated with/to (or mapped to) the configured UL grant having an RSRP larger than (or above) the RSRP threshold. The wireless device may switch (or fallback) from the RACH-less handover procedure to the RACH-based handover procedure based on the first service link PDD being varied/changed more than (or above) the threshold. For example, the wireless device may determine first service link PDD being varied/changed more than (or above) the threshold compared to (or with respect to) the second service link PDD. For example, for the ongoing handover procedure the wireless device may perform the RA procedure. The wireless device may transmit a preamble/PRACH via the target cell. The wireless device may perform the RA procedure based on the RACH configurations (e.g., the dedicated RACH resources).

[0699] In an example embodiment, as shown in FIG. 37, the wireless device may determine the configured/pre- allocated UL grant (of the CG configuration) being valid for the initial PUSCH transmission of the RACH-less handover based on at least one of the following: the first service link PDD being varied/changed less than (or below) the threshold; and/or an SSB of the first set of SSBs associated with/to (or mapped to) the configured UL grant having an RSRP larger than (or above) the RSRP threshold. For example, the wireless device may determine first service link PDD being varied/changed less than (or below) the threshold compared to (or with respect to) the second service link PDD. The wireless device may continue performing the RACH-less handover procedure. The wireless device may transmit the initial PUSCH transmission using the (valid/validated) configured UL grant.

[0700] To determine the configured UL grant is valid, the wireless device may further determine the configured UL grant not colliding (in time domain) with DL symbol(s) indicated by tdd-UL-DL-ConfigurationCommon or tdd-UL-DL- ConfigurationDedicated.

[0701] To determine the configured UL grant is valid, the wireless device may further determine the configured UL grant not colliding (in time domain) with symbol(s) of an SS/PBCH block (of the first/second set of SSBs) with index provided by ssb-Positions/nBurst or ServingCellConfigCommon (e.g., the handover message). For example, the wireless device may not be a half-duplex UE (HD-UE).

[0702] To determine the configured UL grant is valid, the wireless device may further determine the configured UL grant not colliding/overlapping (in time domain) with a first set of symbols (or slots). The first set of symbols may comprise one or more symbols corresponding a first SS/PBCH block (of the first/second set of SSBs) with index provided by ssb-Positions/nBurst or ServingCellConfigCommon (e.g., the handover message). The first set of symbols may comprise one or more symbols corresponding a second SS/PBCH block (of the first/second set of SSBs) with index provided by ssb-Positions/nBurst or ServingCellConfigCommon (e.g., the handover message). [0703] To determine the configured UL grant is valid, the wireless device may determine a first/starting/earliest/initial symbol of the CG PUSCH occasion of the configured UL grant not collid ing/overlapping (in time domain) with the first set of symbols (or slots). To determine the configured UL grant is valid, the wireless device may determine a last/fin al/endin g/latest symbol of the CG PUSCH occasion of the configured UL grant not collid ing/overlappin g (in time domain) with the first set of symbols (or slots).

[0704] To determine the configured UL grant is invalid, the wireless device may determine the first/starting/earl iest/in itial symbol of the CG PUSCH occasion of the configured UL grant collidin g/overlappin g (in time domain) with the first set of symbols (or slots). To determine the configured UL grant is invalid, the wireless device may determine the last/final/ending/latest symbol of the CG PUSCH occasion of the configured UL grant colliding/overlapping (in time domain) with the first set of symbols (or slots). Based on the configured UL grant being invalid, the wireless device may trigger the RA procedure for the ongoing handover. The wireless device may avoid transmitting the initial PUSCH transmission using the (invalidated/invalid) configured UL grant.

[0705] The first set of symbols may comprise at least one symbol prior to a first/initial/starting symbol of the first SS/PBCH block. The first SS/PBCH block may be a next earliest SS/PBCH block (of the first/second set of SSBs) that is after the PUSCH occasion of the configured UL grant. The at least one symbol may correspond to a fourth timing gap. The first SS/PBCH block may be the fourth timing gap (in ms or number of symbols) after the last/final/ending/latest symbol of the CG PUSCH occasion of the configured UL grant. The first SS/PBCH block may be the fourth timing gap (in ms or number of symbols) after the fi rst/starting/earliest/in itial symbol of the CG PUSCH occasion of the configured UL grant.

[0706] The first set of symbols may comprise at least one symbol after a last/final/ending/latest symbol of the second SS/PBCH block. The second SS/PBCH block may be a previous latest SS/PBCH block (of the first/second set of SSBs) that is before/prior to/no later than the PUSCH occasion of the configured UL grant. The at least one symbol may correspond to a fifth timing gap. The second SS/PBCH block may be the fifth timing gap (in ms or number of symbols) after the last/final/ending/latest symbol of the CG PUSCH occasion of the configured UL grant. The second SS/PBCH block may be the fifth timing gap (in ms or number of symbols) after the first/starting/earliest/initial symbol of the CG PUSCH occasion of the configured UL grant.

[0707] The one or more configuration parameters (the handover message) may configure the fourth timing gap and/or the fifth timing gap. In some cases, the fifth timing gap may be the fourth timing gap. In some other cases, the fifth timing gap may be different than the fourth timing gap. The fourth/fifth timing gap may be based on a minimum TA value of the target cell and/or a maximum TA value of the target cell. The fourth/fifth timing gap may be based on the first service link PDD.

[0708] As shown in FIG. 38 and FIG. 39, the wireless device may (based on the handover message) trigger/initiate the handover procedure. The wireless device may trigger/initiate the handover procedure in response to receiving the handover message. The wireless device may trigger/initiate the handover procedure in response to the at least one CHO execution condition being satisfied/met.

[0709] In an example embodiment, based on whether the first service link PDD being varied/changed more than (or above) the threshold or not, the wireless device may determine whether to trigger/initiate the RACH-less handover procedure or the RACH-based handover procedure. The wireless device may determine the handover message configure the wireless device for both the RACH-less handover procedure (via the RACH-less configurations) and the RACH-based handover procedure (via the RACH configurations).

[0710] In an example embodiment, as shown in FIG. 38, based on the first service link PDD being varied/changed more than (or above) the threshold, the wireless device may trigger/initiate the RACH-based handover procedure. For example, the wireless device may determine first service link PDD being varied/changed more than (or above) the threshold compared to (or with respect to) the second service link PDD. For the ongoing RACH-based handover procedure, the wireless device may perform the RA procedure. The wireless device may transmit a preamble/PRACH via the target cell. The wireless device may perform the RA procedure based on the RACH configurations (e.g., the dedicated RACH resources).

[0711] In an example embodiment, as shown in FIG. 39, based on the first service link PDD being varied/changed less than (or below) the threshold, the wireless device may trigger/initiate the RACH-less handover procedure. For example, the wireless device may determine first service link PDD being varied/changed less than (or below) the threshold compared to (or with respect to) the second service link PDD. For example, for the ongoing RACH-less handover procedure, the wireless device may determine the configured/pre-allocated UL grant (of the CG configuration) being valid for the initial PUSCH transmission of the RACH-less handover. The wireless device may determine an SSB of the first set of SSBs associated with/to (or mapped to) the configured UL grant having an RSRP larger than (or above) the RSRP threshold. The wireless device may perform the RACH-less handover procedure. The wireless device may transmit the initial PUSCH transmission (via the second cell) using the configured/pre-allocated UL grant.

[0712] In an example embodiment, based on the first service link PDD being varied/changed less than (or below) the threshold, the wireless device may trigger/initiate the RACH-less handover procedure. The wireless device may determine first service link PDD being varied/changed less than (or below) the threshold compared to (or with respect to) the second service link PDD. For example, for the ongoing RACH-less handover procedure, the wireless device may determine the configured/pre-allocated UL grant (of the CG configuration) being invalid for the initial PUSCH transmission of the RACH-less handover. The wireless device may determine an SSB of the first set of SSBs associated with/to (or mapped to) the configured UL grant having an RSRP smaller than (or below) the RSRP threshold. The wireless device may trigger/initiate the RA procedure for performing the RACH-less handover procedure. The wireless device may transmit the preamble/PRACH via the target cell.

[0713] Embodiments of the present disclosure may improve performance/efficiency of the handover procedure. For example, when the first service link PDD is changed/varied more than the threshold, a possibility that the target cell fails to correctly receive the initial PUSCH transmission may increase. Solutions allow the wireless device to properly (and based on whether the first service link PDD is changed/varied more than the threshold) to determine a type of the handover procedure (e.g. , RACH-less versus RACH-based). Solutions may provide extra condition (and based on whether the first service link PDD is changed/varied more than the threshold) for determining whether the pre-allocated UL grant is valid or not for the initial PUSCH transmission.

[0714] For example, for handover purposes to the target cell in paired or unpaired spectrum where the target cell uses L_max = 4, when the wireless device triggers a RACH-less handover and the RACH-less configuration indicate a configured UL grant, the wireless device may assume the absolute value of the time difference (e.g., the absolute time difference) between the frame #i of the source cell (e.g., a radio frame i) and the frame #i of the target cell is less than the first predefined value (e.g., 1536007)) if the first association pattern period (corresponding to the first periodicity of the configured UL grant) is not equal to 10 ms.

[0715] For example, for an inter frequency handover purposes where the source cell is either in paired or unpaired spectrum and the target cell is in unpaired spectrum and uses L_max = 8, when the wireless device triggers a RACH- less handover and the RACH-less configuration does not indicate a configured UL grant, the wireless device may assume the absolute value of the time difference between the frame #i of the source cell (e.g., a radio frame i) and the frame #i of the target cell is less than the first predefined value (e.g., 768007)).

[0716] For example, for handover purposes to the target cell of an NTN in paired or unpaired spectrum where the target cell uses L_max = 4, the wireless device may assume the absolute value of the time difference (e.g., the absolute time difference) between the frame #i+PDD of the source cell of the NTN and the frame #i of the target cell is less than the first predefined value (e.g., 1536007)) if the second association pattern period (corresponding to the PRACH occasions) is not equal to 10 ms, wherein the PDD is a service link propagation delay between the target cell and the source cell.

[0717] For example, for an inter frequency handover purposes where the source cell of the NTN is either in paired or unpaired spectrum and the target cell of the NTN is in unpaired spectrum and uses L_max = 8, when the wireless device triggers a RACH-less handover and the RACH-less configuration does not indicate a configured UL grant, the wireless device may assume the absolute value of the time difference between the frame #i+PDD of the source cell and the frame #i of the target cell is less than the first predefined value (e.g., 768007)).

[0718] If the target cell and the serving cell are part of NTN, for handover purposes to a target cell where the target cell uses L_max = 4 or L_max = 8, the wireless device may expect to detect frame i in the target cell in a window [1536007) +PDD, —1536007) +PDD] centred around frame i in the source cell, wherein the PDD is the actual service link propagation delay difference between the current cell and the target cell.

[0719] For an uplink grant configured for configured grant Type 1 for RACH-less handover configured in cg-RACH- less-Configuration, when RACH-less handover is triggered and not terminated, the MAC entity of the wireless device may consider sequentially that the configured uplink grant, or the first configured uplink grant in a multi-PUSCH configured grant, in the N^th (N > 0) first periodicity occurs in a symbol for which:

[0720] [(SFN x numberOfSIotsPerFrame * numberOfSymbolsPerSlot)

+ (slot number in the frame x numberOfSymbolsPerSlot) + symbol number in the slot] = timeReferenceSFN x numberOfSIotsPerFrame x numberOfSymbolsPerSlot

[0721] Or

[0722] [(H-SFN x numberOfSFNperH-SFN + SFN) x numberOfSIotsPerFrame * numberOfSymbolsPerSlot

+ (slot number in the frame x numberOfSymbolsPerSlot) + symbol number in the slot] =(timeReferenceH-SFN x numberOfSFNperH-SFN + timeReferenceSFN) x numberOfSIotsPerFrame x numberOfSymbolsPerSlot

[0723] For an uplink grant configured for configured grant Type 1 for RACH-less handover configured in cg-RACH- less-Configuration, when RACH-less handover is triggered and not terminated, the MAC entity of the wireless device may consider sequentially that the configured uplink grant, or the first configured uplink grant in a multi-PUSCH configured grant, in the N^th (N > 0) first periodicity occurs in a symbol for which:

[0724] [(SFN x numberOfSIotsPerFrame * numberOfSymbolsPerSlot)

4- (slot number in the frame x numberOfSymbolsPerSlot) + symbol number in the slot] =(timeReferenceSFN x numberOfSIotsPerFrame x numberOfSymbolsPerSlot

+ (timeDomainOffset+PDD) * numberOfSymbolsPerSlot + S + N x periodicity) modulo (1024 x numberOfSIotsPerFrame * numberOfSymbolsPerSlot)

[0725] Or

[0726] [(H-SFN x numberOfSFNperH-SFN + SFN) x numberOfSIotsPerFrame * numberOfSymbolsPerSlot

4- (slot number in the frame x numberOfSymbolsPerSlot) + symbol number in the slot] =(timeReferenceH-SFN x numberOfSFNperH-SFN + timeReferenceSFN) x numberOfSIotsPerFrame x numberOfSymbolsPerSlot

+ (timeDomainOffset+PDD) * numberOfSymbolsPerSlot + S + N x periodicity) modulo (1024 x 1024 x numberOfSIotsPerFrame * numberOfSymbolsPerSlot)

[0727] wherein the PDD is a service link propagation delay between the target cell and the source cell.

[0728] When the target cell and the source cell are part of the NTN and for this uplink grant configured for RACH-less handover, when RACH-less handover is triggered and not terminated, the timeDomainOffset is based on the assumption that service link propagation delay difference between the target cell and the source cell equals to 0 ms, and wireless device adjusts the actual timeDomainOffset based on the actual propagation delay difference.

[0729] Upon configuration of a configured grant Type 1 for a BWP of a Serving Cell by upper layers, the MAC entity may store the uplink grant provided by upper layers as a configured uplink grant for the indicated BWP of the Serving Cell; and initialise or re-initialise the configured uplink grant to start in the symbol according to timeDomainOffset, timeReferenceSFN, and S (derived from SUV or provided by startSymbol), and to reoccur with the first periodicity. When the target cell and the source cell are part of the NTN and for this uplink grant configured for RACH-less handover, when RACH-less handover is triggered and not terminated, the wireless device may initialise or re-initialise the configured grant further based on the actual service link propagation delay difference between the target cell and the source cell.

[0730] FIG. 40A shows an example flowchart for uplink transmissions per an aspect of the present disclosure. The wireless device may determine a serving link PDD between/corresponding to two cells. In an example embodiment, the wireless device may transmit, via a cell of the two cells, an UL signal/channel based on the service link PDD.

[0731] In an example embodiment, the wireless device may transmit, via a cell of the two cells, the UL signal/channel during/in a transmission occasion determined based on the service link PDD.

[0732] In an example embodiment, the wireless device may determine the transmission occasion based on the service link PDD.

[0733] FIG. 40B shows an example flowchart for configured grant PUSCH transmissions in an NTN per an aspect of the present disclosure. The wireless device may determine a serving link PDD between/corresponding to two cells of the NTN, e.g. , based on the NTN assistance information. In an example embodiment, the wireless device may transmit, via a cell of the two cells, a CG-PUSCH transmission based on the service link PDD.

[0734] In an example embodiment, the wireless device may transmit, via a cell of the two cells, the CG-PUSCH transmission during/in a CG PUSCH transmission occasion, of one or more CG PUSCH transmission occasions, determined based on the service link PDD.

[0735] FIG. 40C shows an example flowchart for configured grant PUSCH transmissions in an NTN per an aspect of the present disclosure. The wireless device may receive, via the first cell of the NTN, a CG configuration indicating a configured UL grant for CG PUSCH transmissions. In an example embodiment, the wireless device may transmit, via the second cell of the NTN and using the configured UL grant, a CG-PUSCH transmission based on the service link PDD. The wireless device may determine a serving link PDD between/corresponding to the first cell and the second cell based on the first NTN-config and the second NTN-config.

[0736] In an example embodiment, the wireless device may transmit, via the second cell of the NTN and using the configured UL grant, the CG-PUSCH transmission during/in a CG PUSCH transmission occasion, of one or more CG PUSCH transmission occasions of the CG configuration, determined based on the service link PDD. [0737] FIG. 41 A shows an example flowchart for configured grant PUSCH transmissions in an NTN per an aspect of the present disclosure. The wireless device may receive, via the first cell of the NTN, a CG configuration indicating a configured UL grant for CG PUSCH transmissions and a time domain offset (e.g. , the first offset). In an example embodiment, the wireless device may transmit, via the second cell of the NTN and using the configured UL grant, a CG-PUSCH transmission based on the service link PDD and the time domain offset. The wireless device may determine a serving link PDD between/corresponding to the first cell and the second cell based on the first NTN-config and the second NTN-config.

[0738] In an example embodiment, the wireless device may transmit, via the second cell of the NTN and using the configured UL grant, the CG-PUSCH transmission during/in a CG PUSCH transmission occasion, of the CG configuration, determined based on the service link PDD and the time domain offset.

[0739] FIG. 41 B shows an example flowchart for RACH-less handover per an aspect of the present disclosure. The wireless device may receive the RACH-less configurations for handover from the first cell to the second cell. The RACH-less configurations may configure/indicate a CG configuration indicating a configured UL grant for CG PUSCH transmissions and a time domain offset (e.g., the first offset). In an example embodiment, the wireless device may transmit, via the second cell and using the configured UL grant, the initial PUSCH transmission based on the service link PDD and the time domain offset. The wireless device may determine a serving link PDD between/corresponding to the first cell and the second cell based on the first NTN-config and the second NTN-config.

[0740] In an example embodiment, the wireless device may transmit, via the second cell of and using the configured UL grant, the initial PUSCH transmission during/in a CG PUSCH transmission occasion, of the CG configuration, determined based on the service link PDD and the time domain offset.

[0741] FIG. 41 C shows an example flowchart for RACH-less handover per an aspect of the present disclosure. The wireless device may receive the RACH-less configurations for handover from the first cell to the second cell. The RACH-less configurations may configure/indicate a CG configuration indicating a configured UL grant for CG PUSCH transmissions and a time domain offset (e.g., the first offset). In an example embodiment, the wireless device may transmit, via the second cell and using the configured UL grant, the initial PUSCH transmission based on a summation of the service link PDD and the time domain offset. The wireless device may add the service link PDD and the time domain offset to determine a CG PUSCH transmission occasion, of the CG configuration, for the transmission of the initial PUSCH transmission. The wireless device may transmit the initial PUSCH transmission in/during the determined CG PUSCH transmission occasion.

[0742] FIG. 42A shows an example flowchart for DL synchronization as part of a handover procedure per an aspect of the present disclosure. The wireless device may receive the handover message indicating handover from the first cell to the second cell. The handover message may comprise/configure/indicate the RACH-less configurations (for performing the RACH-less handover) and the RACH configurations (for performing an RA procedure as part of the handover). The RACH-less configurations may configure/indicate the first periodicity of the CG configuration for the initial PUSCH transmission. The CG configuration may indicate/configure the pre-allocated (or configured) UL grant for the initial PUSCH transmission. The RACH-configurations may indicate the second periodicity of the PRACH occasions.

[0743] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations indicating the pre-allocated UL grant, the wireless device may perform the DL synchronization to the target cell/satellite based on the first association pattern period. The wireless device may determine the first association pattern period based on the first periodicity. By performing the DL synchronization to the target cell/satellite, the wireless device may determine/obtain the SFN in/of the target cell/satellite. The wireless device may transmit the initial PUSCH transmission based on the determined SFN in/of the target cell/satellite. The wireless device may determine a CG PUSCH occasion for transmission of the initial PUSCH transmission based on the determined SFN in/of the target cell/satellite.

[0744] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations indicating the pre-allocated UL grant, the wireless device may perform the DL synchronization to the target cell/satellite based on the first association pattern period and the second association pattern. The wireless device may perform the DL synchronization to the target cell/satellite based on a minimum of the first association pattern period and the second association pattern. The wireless device may perform the DL synchronization to the target cell/satellite based on a maximum of the first association pattern period and the second association pattern.

[0745] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations indicating the pre-allocated UL grant, the wireless device may perform the DL synchronization to the target cell/satellite based on determining whether the first association pattern period is equal to a first value (e.g., 10 ms) or not and/or whether the second association pattern is equal to the first value or not. The wireless device may perform the DL synchronization to the target cell/satellite based on at least one of the first association pattern period and the second association pattern not being equal to the first value. The wireless device may perform the DL synchronization to the target cell/satellite based on both the first association pattern period and the second association pattern not being equal to the first value.

[0746] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations not indicating the pre-allocated UL grant, the wireless device may perform the DL synchronization to the target cell/satellite based on the second association pattern period. The wireless device may determine the second association pattern period based on the second periodicity. The wireless device may perform the DL synchronization to the target cell/satellite based on determining whether the second association pattern is equal to the first value or not. [0747] FIG. 42B shows an example flowchart for DL synchronization as part of a handover procedure per an aspect of the present disclosure. The wireless device may receive the handover message indicating handover from the first cell to the second cell. The handover message may comprise/configure/indicate the RACH-less configurations (for performing the RACH-less handover) and the RACH configurations (for performing an RA procedure as part of the handover). The RACH-less configurations may configure/indicate the first periodicity of the CG configuration for the initial PUSCH transmission. The CG configuration may indicate/configure the pre-allocated (or configured) UL grant for the initial PUSCH transmission. The RACH-configurations may indicate the second periodicity of the PRACH occasions.

[0748] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations indicating the pre-allocated UL grant, the wireless device may determine the SFN in/of the target cell/satellite based on the first association pattern period (corresponding to the CG configuration for the pre-allocated UL grant) and/or the SFN in/of the source cell. The wireless device may determine the first association pattern period based on the first periodicity. The wireless device may perform the RACH-less handover based on the SFN in/of the target cell/satellite.

[0749] FIG. 43A shows an example flowchart for RACH-less handover procedure as part of a handover procedure per an aspect of the present disclosure. The wireless device may receive the handover message indicating handover from the first cell to the second cell. The handover message may comprise/configure/indicate the RACH-less configurations (for performing the RACH-less handover) and the RACH configurations (for performing an RA procedure as part of the handover). The RACH-less configurations may configure/indicate the first periodicity of the CG configuration for the initial PUSCH transmission. The CG configuration may indicate/configure the pre-allocated (or configured) UL grant for the initial PUSCH transmission. The RACH-configurations may indicate the second periodicity of the PRACH occasions.

[0750] In an example embodiment, for the RACH-less handover procedure and based on the RACH-less configurations indicating the pre-allocated UL grant, the wireless device may determine the SFN in/of the target cell/satellite based on the first association pattern period (corresponding to the CG configuration for the pre-allocated UL grant) and/or the SFN in/of the source cell. The wireless device may determine the first association pattern period based on the first periodicity. The wireless device may perform the RACH-less handover based on the SFN in/of the target cell/satellite. The wireless device may transmit the initial PUSCH transmission based on the determined SFN in/of the target cell/satellite. The wireless device may determine a CG PUSCH occasion for transmission of the initial PUSCH transmission based on the determined SFN in/of the target cell/satellite.

[0751] FIG. 43B shows an example flowchart for handover procedure as part of a handover procedure per an aspect of the present disclosure. The wireless device may receive the handover message indicating handover from the first cell to the second cell. The handover message may comprise/configure/indicate the RACH-less configurations (for performing the RACH-less handover) and the RACH configurations (for performing an RA procedure as part of the handover). The RACH-less configurations may configure/indicate the CG configuration for the initial PUSCH transmission. The CG configuration may indicate/configure the pre-allocated (or configured) UL grant for the initial PUSCH transmission. The RACH-configurations may indicate the dedicated RACH resources. [0752] In an example embodiment, the wireless device may, in response to the handover message, determine whether to trigger/initiate the RACH-less handover procedure or the RACH-based handover procedure based on a variation of the first service link PDD between/corresponding to the first cell (the source cell/satellite) and the second cell (the target cell/satellite).

[0753] In an example embodiment, the wireless device may, in response to the handover message, determine whether to trigger/initiate the RACH-less handover procedure or the RACH-based handover procedure based on whether the first service link PDD changed/varied above the threshold or not.

[0754] FIG. 44 shows an example flowchart for handover procedure as part of a handover procedure per an aspect of the present disclosure. The wireless device may receive the handover message indicating handover from the first cell to the second cell. The handover message may comprise/configure/indicate the RACH-less configurations (for performing the RACH-less handover) and the RACH configurations (for performing an RA procedure as part of the handover). The RACH-less configurations may configure/indicate the CG configuration for the initial PUSCH transmission. The CG configuration may indicate/configure the pre-allocated (or configured) UL grant for the initial PUSCH transmission. The RACH-configurations may indicate the dedicated RACH resources.

[0755] In an example embodiment, the wireless device may, in response to the handover message, determine a type of the handover (e.g., RACH-less or RACH-based) based on a variation of the first service link PDD between/corresponding to the first cell (the source cell/satellite) and the second cell (the target cell/satellite).

[0756] In an example embodiment, the wireless device may, in response to the handover message, determine whether a type of the handover is the RACH-less or the RACH-based based on whether the first service link PDD changed/varied above the threshold or not.

[0757] In an example embodiment, the wireless device may, in response to triggering/initiating the handover procedure (e.g., in response to the handover message or based on the at least one CHO execution condition being satisfied), determine a type of the handover (e.g., RACH-less or RACH-based) based on a variation of the first service link PDD between/corresponding to the first cell (the source cell/satellite) and the second cell (the target cell/satellite). [0758] In an example embodiment, the wireless device may, in response to triggering/initiating the handover procedure (e.g., in response to the handover message or based on the at least one CHO execution condition being satisfied), determine whether a type of the handover is the RACH-less or the RACH-based based on whether the first service link PDD changed/varied above the threshold or not.

[0759] For example, the wireless device may determine whether the first service link PDD changed/varied above the threshold or not.

[0760] In response to the first service link PDD changed/varied above the threshold, the wireless device may determine the type of the handover procedure is the RACH-based. The wireless device may trigger/initiate the RA procedure for performing the handover. The wireless device may transmit a preamble (for the triggered RA procedure) via/suing the dedicated RACH resources. [0761] In response to the first service link PDD changed/varied below the threshold, the wireless device may determine the type of the handover procedure is the RACH-less. The wireless device may perform the RACH-less handover procedure by transmitting the initial PUSCH transmission via the pre-allocated UL grant.

[0762] FIG. 44 shows an example flowchart for handover procedure as part of a handover procedure per an aspect of the present disclosure. The wireless device may receive the handover message indicating handover from the first cell to the second cell. The handover message may comprise/configure/indicate the RACH-less configurations (for performing the RACH-less handover) and the RACH configurations (for performing an RA procedure as part of the handover). The RACH-less configurations may configure/indicate the CG configuration for the initial PUSCH transmission. The CG configuration may indicate/configure the pre-allocated (or configured) UL grant for the initial PUSCH transmission. The RACH-configurations may indicate the dedicated RACH resources.

[0763] In an example embodiment, the wireless device may, in response to triggering/initiating the RACH-less handover procedure, determine whether to trigger/initiate the RA procedure based on a variation of the first service link PDD between/corresponding to the first cell (the source cell/satellite) and the second cell (the target cell/satellite). For example, the wireless device may determine whether the first service link PDD changed/varied above the threshold or not.

[0764] In response to the first service link PDD changed/varied above the threshold, the wireless device may trigger/initiate the RA procedure for performing the RACH-less handover. The wireless device may transmit a preamble (for the triggered RA procedure) via/suing the dedicated RACH resources.

[0765] In response to the first service link PDD changed/varied above the threshold, the wireless device may determine whether an SSB associated with the pre-allocated UL grant having an RSRP above the RSRP threshold or not.

[0766] Based on the SSB associated with the pre-allocated UL grant having the RSRP above the RSRP threshold, the wireless device may avoid triggering/initiating the RA procedure for performing the RACH-less handover. The wireless device may transmit the initial PUSCH transmission using the pre-allocated UL grant.

[0767] Based on the SSB associated with the pre-allocated UL grant having the RSRP above the RSRP threshold, the wireless device may trigger/initiate the RA procedure for performing the RACH-less handover. The wireless device may transmit a preamble (for the triggered RA procedure) via/suing the dedicated RACH resources.

[0768] FIG. 45 shows an example flowchart for handover procedure as part of a handover procedure per an aspect of the present disclosure. The wireless device may receive the handover message via first cell. The handover message may indicate handover from the first cell to a second cell. The handover message comprises RACH-less configuration indicating a pre-allocated UL grant for initial PUSCH transmission. The RACH configurations may indicate PRACH resources. [0769] In an example embodiment, the wireless device may determine whether to trigger or initiate a random access procedure or not based on a variation of service link propagation delay difference (PDD) between the first cell and the second cell in response to initiating or triggering the RACH-less handover.

[0770] In an example embodiment, the service link PDD between is changed or varied more than the threshold. The wireless device may trigger or initiate the random access procedure.

[0771] In an example embodiment, the service link PDD between is changed or varied less than the threshold. The wireless device may determine whether an SSB associated with the pre-allocated UL grant has an reference signal received power (RSRP) above an RSRP threshold or not. The wireless device may trigger or initiate the RA procedure based on the RSRP being below the RSRP threshold. The wireless device may perform the RACH-less handover by transmitting the initial PUSCH transmission based on the RSRP being above the RSRP threshold.

[0772] Example embodiments may enhance efficiency/performance of handover procedure. Some embodiments may reduce possibility of the target base station failing to receive the initial PUSCH transmission.

[0773] Some embodiments may allow the wireless device to properly determine (e.g., based the service link PDD between the source cell and the target cell) a transmission occasion for the initial PUSCH transmission. Some embodiments allow the wireless device to determine (e.g., based the service link PDD between the source cell and the target cell) whether to trigger/initiate an RA procedure for the RACH-less handover. Some embodiments allow the wireless device to determine (e.g., based the service link PDD between the source cell and the target cell) whether the pre-allocated UL grant is valid for the initial PUSCH transmission.

[0774] Clause 1. A method comprising: receiving, by a wireless device and via a first cell, a radio resource control (RRC) reconfiguration message indicating: a random access channel (RACH)-less handover to a second cell; and a configuration uplink grant indicating an uplink resource for the second cell; and transmitting an uplink transmission via the uplink resource of the second cell, wherein the uplink resource is determined based on a service link propagation delay difference between the first cell and the second cell.

[0775] Clause 2. A method comprising: transmitting, by a wireless device, an uplink transmission via an uplink resource of a first cell, wherein the uplink resource is determined based on a service link propagation delay difference between the first cell and a second cell.

[0776] Clause 3. The method of clause 2, wherein the uplink resource is configured by the second cell.

[0777] Clause 4. The method of clause 3, further comprising receiving a first message via the second cell, wherein the first message indicates the uplink resource.

[0778] Clause 5. The method of clause 4, wherein the first message is a radio resource control (RRC) message.

[0779] Clause 6. The method of clause 5, wherein the RRC message is an RRC reconfiguration message indicating random access channel (RACH)-less handover.

[0780] Clause 7. The method of clause 6, wherein the RACH-less handover is for handover from the second cell to the first cell. [0781] Clause 8. The method of any one of clauses 6 to 7, wherein the uplink transmission is a first PUSCH transmission for the RACH-less handover.

[0782] Clause 9. The method of any one of clauses 3 to 8, wherein the first message comprises a configured uplink grant indicating the uplink resource.

[0783] Clause 10. The method of clause 9, wherein the configured uplink grant is a configured grant Type 1.

[0784] Clause 11. The method of any one of clauses 9 to 10, wherein: determining the uplink resource comprises: initializing the configured uplink grant to start in a symbol; or re-initializing the configured uplink grant to start in the symbol; and the symbol is determined based on the service link propagation delay difference between the first cell and the second cell.

[0785] Clause 12. The method of clause 11, wherein: the first message indicates a time domain offset for the configured uplink grant; and the symbol is further determined based on the time domain offset.

[0786] Clause 13. The method of any one of clauses 10 to 11 , wherein: the uplink transmission is during a transmission occasion; and the transmission occasion starts in the symbol.

[0787] Clause 14. The method of clause 12, wherein performing the RACH-less handover comprises transmitting the uplink transmission via the first cell during the transmission occasion.

[0788] Clause 15. The method of any one of clauses 2 to 14, wherein the uplink resource is for uplink transmissions via the first cell.

[0789] Clause 16. The method of any one of clauses 2 to 15, wherein the uplink transmission is a configured grant Type 1 physical uplink shared channel (PUSCH) transmission.

[0790] Clause 17. The method of any one of clauses 2 to 16, wherein the uplink transmission is for transmitting an RRC reconfiguration complete message.

[0791] Clause 18. The method of any one of clauses 2 to 17, further comprising determining a frame number of the first cell based on: a frame number of the second cell; and the service link propagation delay difference.

[0792] Clause 19. The method of clause 18, wherein a transmission occasion of the uplink transmission, using the uplink resource, is determined based on the frame number of the first cell.

[0793] Clause 20. The method of any one of clauses 2 to 19, further comprising receiving, via the second cell, a second message comprising non-terrestrial network (NTN) assistance information.

[0794] Clause 21. The method of clause 20, wherein the second message comprises the first message.

[0795] Clause 22. The method of any one of clauses 20 to 21 , wherein the second message is a non-terrestrial network (NTN) specific broadcast information block (SIB).

[0796] Clause 23. The method of any one of clauses 20 to 22, wherein the second message indicates the satellite switch with resynchronization.

[0797] Clause 24. The method of any one of clauses 20 to 23, further comprising determining the service link propagation delay difference based on the non-terrestrial network (NTN) assistance information. [0798] Clause 25. The method of any one of clauses 20 to 24, wherein the NTN assistance information comprises: a first NTN configuration corresponding to the first cell; and a second NTN configuration corresponding to the second cell. [0799] Clause 26. The method of clause 25, wherein the service link propagation delay is determined based on the first NTN configuration and the second NTN configuration.

[0800] Clause 27. The method of any one of clauses 25 to 26, wherein: the first NTN configuration comprises ephemeris information of a first NTN node; the first cell is served by the first NTN node; the second NTN configuration comprises ephemeris information of a second NTN node; and the second cell is served by the second NTN node. [0801] Clause 28. The method of clause 27, wherein: the first NTN node is a target satellite; and the second NTN node is a source satellite.

[0802] Clause 29. The method of any one of clauses 27 to 28, wherein: the service link propagation delay difference is based on a difference between a service link propagation delay of the first cell and a service link propagation delay of the second cell; the service link propagation delay of the first cell is determined based on the ephemeris information of the first NTN node; and the service link propagation delay of the second cell is determined based on the ephemeris information of the second NTN node.

[0803] Clause 30. The method of any one of clauses 2 to 29, wherein the first cell is part of a non-terrestrial network (NTN).

[0804] Clause 31. The method of any one of clauses 2 to 30, wherein the second cell is part of the NTN.

[0805] Clause 32. The method of any one of clauses 2 to 31 , a physical cell identifier (PCI) of the first cell is equal to a PCI of the second cell.

[0806] Clause 33. The method of any one of clauses 2 to 32, further comprising performing a satellite switch with resynchronization, wherein the transmitting the uplink transmission is after the satellite switch with resynchronization. [0807] Clause 34. The method of clause 33, wherein the satellite switch with resynchronization is for switching from a first NTN node of the second cell to a second NTN node of the second cell without changing the PCI of the second cell. [0808] Clause 35. The method of any one of clauses 33 to 34, wherein the satellite switch with resynchronization comprises an interruption time that is based on the service link propagation delay difference.

[0809] Clause 36. The method of clause 35, wherein the uplink resource is after the interruption time.

[0810] Clause 37. The method of any one of clauses 35 to 36, wherein the interruption time is further based on an RRC processing time.

[0811] Clause 38. The method of any one of clauses 35 to 37, wherein the interruption time is further based on a duration for receiving a synchronization signal block (SSB) from the first cell.

[0812] Clause 39. The method of any one of clauses 35 to 38, wherein the interruption time is further determined based on an SSB processing time.

[0813] Clause 40. The method of any one of clauses 35 to 39, wherein: the performing the satellite switch with resynchronization is during a window; and the window comprises the interruption time. [0814] Clause 41. The method of any one of clauses 2 to 40, wherein: the first cell comprises a first NTN node; and the second cell comprises a second NTN node.

[0815] Clause 42. A method comprising: receiving, by a wireless device, a message indicating a satellite switch from a first satellite of a cell to a second satellite of the cell; determining an interruption time based on a propagation delay between the first satellite and the second satellite; obtaining, during the interruption time, a downlink synchronization with the cell; and transmitting, via the second satellite of the cell, an uplink transmission.

[0816] Clause 43. The method of clause 42, wherein the message comprises a radio resource control (RRC) message.

[0817] Clause 44. The method of any one of clauses 42 to 43, wherein the satellite switch is: with resynchronization; and without changing a physical cell identifier (PCI) of a cell.

[0818] Clause 45. The method of any one of clauses 42 to 44, wherein determining the interruption time is further based on periodicity of a synchronization signal block (SSB).

[0819] Clause 46. The method of any one of clauses 42 to 45, wherein determining the interruption time is further based on an RRC processing delay.

[0820] Clause 47. The method of any one of clauses 42 to 46, wherein determining the interruption time is further based on a synchronization signal block (SSB) processing delay.

[0821] Clause 48. The method of any one of clauses 42 to 47, wherein the message further indicates a periodicity of an SSB.

[0822] Clause 49. An apparatus comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform the method of any one of clauses 1 to 48. [0823] Clause 50. A non -transitory computer-readable medium comprising instructions that, when executed by one or more processors of an apparatus, cause the apparatus to perform the method of any one of clauses 1 to 48.

[0824] Clause 51. A method comprising: receiving, by a wireless device via a cell of a non-terrestrial network (NTN), a radio resource control (RRC) message indicating a satellite switch with resynchronization and without changing a physical cell identifier (PCI) of the cell, wherein the satellite switch with resynchronization is for switching from a first satellite of the cell to a second satellite of the cell; obtaining, for performing the satellite switch with resynchronization, downlink synchronization with the cell and during an interruption time corresponding to the satellite switch with resynchronization, wherein the interruption time is determined based on a propagation delay difference between the first satellite and the second satellite; and transmitting, via the second satellite of the cell, an uplink transmission.

[0825] Clause 52. The method of clause 51, further comprising receiving a second RRC message indicating a periodicity of a synchronization signal block (SSB).

[0826] Clause 53. The method of clause 52, wherein the interruption time is determined further based on the periodicity of the SSB. [0827] Clause 54. The method of any one of clauses 51 to 53, wherein the interruption time is determined further based on an RRC processing delay.

[0828] Clause 55. The method of any one of clauses 51 to 54, wherein the interruption time is determined further based on an SSB processing delay.

[0829] Clause 56. The method of any one of clauses 51 to 55, wherein the obtaining downlink synchronization with the cell comprises receiving at least one SSB via the second satellite of the cell.

[0830] Clause 57. The method of any one of clauses 51 to 56, wherein the transmitting the uplink transmission is after the interruption time for the obtaining the downlink synchronization.

[0831] Clause 58. The method of any one of clauses 51 to 57, wherein the transmitting the uplink transmission is after performing the satellite switch with resynchronization.

[0832] Clause 59. The method of any one of clauses 51 to 58, further comprising performing the satellite switch with resynchronization is in response to the RRC message.

[0833] Clause 60. A method comprising: receiving, by a wireless device via a cell of a non-terrestrial network (NTN), one or more radio resource control (RRC) messages indicating: a satellite switch with resynchronization and without changing a physical cell identifier (PCI) of the cell, wherein the satellite switch with resynchronization is for switching from a first satellite of the cell to a second satellite of the cell; and a periodicity of a synchronization signal block (SSB); obtaining, for performing the satellite switch with resynchronization, downlink synchronization with the cell and during an interruption time corresponding to the satellite switch with resynchronization, wherein the interruption time is determined based on: a propagation delay difference between the first satellite and the second satellite; and the periodicity of the SSB; and transmitting, via the second satellite of the cell, an uplink transmission.

[0834] Clause 61. A method comprising: receiving, by a wireless device via a cell of a non-terrestrial network (NTN), a radio resource control (RRC) message indicating a satellite switch with resynchronization and without changing a physical cell identifier (PCI) of the cell, wherein the satellite switch with resynchronization is for switching from a first satellite of the cell to a second satellite of the cell; obtaining, for performing the satellite switch with resynchronization, downlink synchronization with the cell and during an interruption time corresponding to the satellite switch with resynchronization, wherein the interruption time is determined based on: a propagation delay difference between the first satellite and the second satellite; an RRC processing delay; and a synchronization signal block (SSB) processing delay; and transmitting, via the second satellite of the cell, an uplink transmission.

[0835] Clause 62. A method comprising: receiving, by a wireless device via a cell of a non-terrestrial network (NTN), one or more radio resource control (RRC) messages indicating: a satellite switch with resynchronization and without changing a physical cell identifier (PCI) of the cell, wherein the satellite switch is for switching from a first satellite of the cell to a second satellite of the cell; and a periodicity of a synchronization signal block (SSB); obtaining, for performing the satellite switch with resynchronization, downlink synchronization with the cell and during an interruption time corresponding to the satellite switch with resynchronization, wherein the interruption time is determined based on: a propagation delay difference between the first satellite and the second satellite; an RRC processing delay; a synchronization signal block (SSB) processing delay; and the periodicity of the SSB; and transmitting, via the second satellite of the cell, an uplink transmission.

Claims

CLAIMS What is claimed is:

1. A method comprising: receiving, by a wireless device and via a first cell, a radio resource control (RRC) reconfiguration message indicating: a random access channel (RACH)-less handover to a second cell; and a configuration uplink grant indicating an uplink resource for the second cell; and transmitting an uplink transmission via the uplink resource for the second cell, wherein the uplink resource is determined based on a service link propagation delay difference between the first cell and the second cell.

2. A method comprising: transmitting, by a wireless device, an uplink transmission via an uplink resource of a first cell, wherein the uplink resource is determined based on a service link propagation delay difference between the first cell and a second cell.

3. The method of claim 2, wherein the uplink resource is configured by the second cell.

4. The method of claim 3, further comprising receiving a first message via the second cell, wherein the first message indicates the uplink resource.

5. The method of claim 4, wherein the first message is a radio resource control (RRC) message.

6. The method of claim 5, wherein the RRC message is an RRC reconfiguration message indicating random access channel (RACH)-less handover.

7. The method of claim 6, wherein the RACH-less handover is for handover from the second cell to the first cell.

8. The method of any one of claims 6 to 7, wherein the uplink transmission is a first PUSCH transmission for the RACH-less handover.

9. The method of any one of claims 3 to 8, wherein the first message comprises a configured uplink grant indicating the uplink resource.

10. The method of claim 9, wherein the configured uplink grant is a configured grant Type 1.

11. The method of any one of claims 9 to 10, wherein: determining the uplink resource comprises: initializing the configured uplink grant to start in a symbol; or re-initializing the configured uplink grant to start in the symbol; and the symbol is determined based on the service link propagation delay difference between the first cell and the second cell.

12. The method of claim 11, wherein: the first message indicates a time domain offset for the configured uplink grant; and the symbol is further determined based on the time domain offset.

13. The method of any one of claims 11 to 12, wherein: the uplink transmission is during a transmission occasion; and the transmission occasion starts in the symbol.

14. The method of claim 13, wherein performing the RACH-less handover comprises transmitting the uplink transmission via the first cell during the transmission occasion.

15. The method of any one of claims 2 to 14, wherein the uplink resource is for uplink transmissions via the first cell.

16. The method of any one of claims 2 to 15, wherein the uplink transmission is a configured grant Type 1 physical uplink shared channel (PUSCH) transmission.

17. The method of any one of claims 2 to 16, wherein the uplink transmission is for transmitting an RRC reconfiguration complete message.

18. The method of any one of claims 2 to 17, further comprising determining a frame number of the first cell based on: a frame number of the second cell; and the service link propagation delay difference.

19. The method of claim 18, wherein a transmission occasion of the uplink transmission, using the uplink resource, is determined based on the frame number of the first cell.

20. The method of any one of claims 2 to 19, further comprising receiving, via the second cell, a second message comprising non-terrestrial network (NTN) assistance information.

21. The method of claim 20, wherein the second message comprises the first message.

22. The method of any one of claims 20 to 21 , wherein the second message is a non-terrestrial network (NTN) specific broadcast information block (SIB).

23. The method of any one of claims 20 to 22, wherein the second message indicates the satellite switch with resynchronization.

24. The method of any one of claims 20 to 23, further comprising determining the service link propagation delay difference based on the non-terrestrial network (NTN) assistance information.

25. The method of any one of claims 20 to 24, wherein the NTN assistance information comprises: a first NTN configuration corresponding to the first cell; and a second NTN configuration corresponding to the second cell.

26. The method of claim 25, wherein the service link propagation delay is determined based on the first NTN configuration and the second NTN configuration.

27. The method of any one of claims 25 to 26, wherein: the first NTN configuration comprises ephemeris information of a first NTN node; the first cell is served by the first NTN node; the second NTN configuration comprises ephemeris information of a second NTN node; and the second cell is served by the second NTN node.

28. The method of claim 27, wherein: the first NTN node is a target satellite; and the second NTN node is a source satellite.

29. The method of any one of claims 27 to 28, wherein: the service link propagation delay difference is based on a difference between a service link propagation delay of the first cell and a service link propagation delay of the second cell; the service link propagation delay of the first cell is determined based on the ephemeris information of the first NTN node; and the service link propagation delay of the second cell is determined based on the ephemeris information of the second NTN node.

30. The method of any one of claims 2 to 29, wherein the first cell is part of a non-terrestrial network (NTN).

31. The method of any one of claims 2 to 30, wherein the second cell is part of the NTN.

32. The method of any one of claims 2 to 31 , a physical cell identifier (PCI) of the first cell is equal to a PCI of the second cell.

33. The method of any one of claims 2 to 32, further comprising performing a satellite switch with resynchronization, wherein the transmitting the uplink transmission is after the satellite switch with resynchronization.

34. The method of claim 33, wherein the satellite switch with resynchronization is for switching from a first NTN node of the second cell to a second NTN node of the second cell without changing the PCI of the second cell.

35. The method of any one of claims 33 to 34, wherein the satellite switch with resynchronization comprises an interruption time that is based on the service link propagation delay difference.

36. The method of claim 35, wherein the uplink resource is after the interruption time.

37. The method of any one of claims 35 to 36, wherein the interruption time is further based on an RRC processing time.

38. The method of any one of claims 35 to 37, wherein the interruption time is further based on a duration for receiving a synchronization signal block (SSB) from the first cell.

39. The method of any one of claims 35 to 38, wherein the interruption time is further determined based on an SSB processing time.

40. The method of any one of claims 35 to 39, wherein: the performing the satellite switch with resynchronization is during a window; and the window comprises the interruption time.

41. The method of any one of claims 2 to 40, wherein: the first cell comprises a first NTN node; and the second cell comprises a second NTN node.

42. A method comprising: receiving, by a wireless device, a message indicating a satellite switch from a first satellite of a cell to a second satellite of the cell; determining an interruption time based on a propagation delay between the first satellite and the second satellite; obtaining, during the interruption time, a downlink synchronization with the cell; and transmitting, via the second satellite of the cell, an uplink transmission based on the downlink synchronization.

43. The method of claim 42, wherein the message comprises a radio resource control (RRC) message.

44. The method of any one of claims 42 to 43, wherein the satellite switch is: with resynchronization; and without changing a physical cell identifier (PCI) of a cell.

45. The method of any one of claims 42 to 44, wherein determining the interruption time is further based on periodicity of a synchronization signal block (SSB).

46. The method of any one of claims 42 to 45, wherein determining the interruption time is further based on an RRC processing delay.

47. The method of any one of claims 42 to 46, wherein determining the interruption time is further based on a synchronization signal block (SSB) processing delay.

48. The method of any one of claims 42 to 47, wherein the message further indicates a periodicity of an SSB.

49. An apparatus comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform the method of any one of claims 1 to 48.

50. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors of an apparatus, cause the apparatus to perform the method of any one of claims 1 to 48.