CN115707056A

CN115707056A - Method and apparatus for switching UE between cell TRPs

Info

Publication number: CN115707056A
Application number: CN202210865893.0A
Authority: CN
Inventors: 阿维克·森古普塔; 阿列克谢·达维多夫
Original assignee: Intel Corp
Current assignee: Intel Corp
Priority date: 2021-08-06
Filing date: 2022-07-22
Publication date: 2023-02-17

Abstract

The present disclosure provides a method and apparatus for handover of a UE between cell TRPs. The device comprises: an interface; and a processor coupled with the interface and configured to: detecting L1 parameter values of a plurality of non-serving cell TRPs for a UE; determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value; and handing over the UE to one of the at least one candidate serving cell TRP. Other embodiments are also disclosed and claimed.

Description

Method and apparatus for switching UE between cell TRPs

Priority declaration

This application is based on U.S. provisional application serial No. 63/230,659 filed on 8/6/2021 and claiming priority to that application. The entire contents of this application are incorporated herein by reference in their entirety.

Technical Field

Embodiments of the present disclosure relate generally to wireless communications and, more particularly, to an apparatus and method for switching a UE between cell TRPs.

Background

Mobile communications have evolved significantly from early speech systems to today's highly sophisticated integrated communication platforms. Next generation wireless communication systems, fifth generation (5G) or New Radios (NR) will provide information access and data sharing through various terminals and applications anytime and anywhere. NR promises to be a unified network/system, aimed at meeting distinct and sometimes conflicting performance dimensions and services. This different multi-dimensional requirement is driven by different services and applications. In general, NRs can evolve based on third generation partnership project (3 GPP) Long Term Evolution (LTE) -advanced and other potential new Radio Access Technologies (RATs), enriching people's lives with better, simple, and seamless wireless connectivity solutions. The NR can enable everything over the wireless connection and provide fast, rich content and services.

Disclosure of Invention

An aspect of the present disclosure provides an apparatus, comprising: an interface; and a processor coupled with the interface and configured to: detecting L1 parameter values of a plurality of non-serving cell TRPs for a UE; determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value; and handing over the UE to one of the at least one candidate serving cell TRP.

One aspect of the present disclosure provides a method, comprising: detecting L1 parameter values of a plurality of non-serving cell TRPs for a UE; determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value; and handing over the UE to one of the at least one candidate serving cell TRP.

Drawings

Embodiments of the present disclosure will be described by way of example, and not limitation, in the figures of the accompanying drawings in which like references indicate similar elements.

Fig. 1 illustrates an example architecture of a system according to some embodiments of the present disclosure.

Fig. 2 illustrates an example architecture of a system including a 5GC according to some embodiments of the present disclosure.

Fig. 3 shows a block diagram of an example of an apparatus for handover of a UE between cell TRPs according to an embodiment of the present disclosure.

Fig. 4 shows a flowchart of an example of a method for handover of a UE between cell TRPs according to an embodiment of the present disclosure.

Fig. 5 shows a flowchart of an example of a handover step in a method for handover of a UE between cell TRPs according to an embodiment of the present disclosure.

Fig. 6 shows a schematic diagram of an example of handover of a UE between cell TRPs according to an embodiment of the present disclosure.

Fig. 7 illustrates a network according to various embodiments of the present disclosure.

Fig. 8 schematically illustrates a wireless network in accordance with various embodiments of the present disclosure.

Fig. 9 is a block diagram illustrating components capable of reading instructions from a machine-readable or computer-readable medium and performing any one or more of the methodologies discussed herein, according to some example embodiments.

Detailed Description

Various aspects of the illustrative embodiments will be described using terms commonly employed by those skilled in the art to convey the substance of the disclosure to others skilled in the art. However, it will be readily understood by those skilled in the art that many alternative embodiments may be practiced using portions of the described aspects. For purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the illustrative embodiments. However, it will be apparent to one skilled in the art that alternative embodiments may be practiced without the specific details. In other instances, well-known features may be omitted or simplified in order not to obscure the illustrative embodiments.

Further, various operations will be described as multiple discrete operations, in a manner that is most helpful in understanding the illustrative embodiments; however, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations need not be performed in the order of presentation.

The phrases "in an embodiment," "in one embodiment," and "in some embodiments" are used repeatedly herein. The phrase generally does not refer to the same embodiment; however, it may refer to the same embodiment. The terms "comprising," "having," and "including" are synonymous, unless the context dictates otherwise. The phrases "A or B" and "A/B" mean "(A), (B) or (A and B)".

As shown in FIG. 1, the system 100 can include a UE101 a and a UE101 b (collectively referred to as "UEs 101"). As used herein, the term "user equipment" or "UE" may refer to devices having radio communication capabilities and may describe remote users of network resources in a communication network. The terms "user equipment" or "UE" may be considered synonyms and may be referred to as a client, a mobile phone, a mobile device, a mobile terminal, a user terminal, a mobile unit, a mobile station, a mobile user, a subscriber, a user, a remote station, an access agent, a user agent, a receiver, a radio, a reconfigurable mobile, and the like. Furthermore, the terms "user equipment" or "UE" may include any type of wireless/wired device or any computing device that includes a wireless communication interface. In this example, the UE101 is shown as a smartphone (e.g., a handheld touchscreen mobile computing device connectable to one or more cellular networks), but may also include any mobile or non-mobile computing device, such as a consumer electronics device, a cellular phone, a smartphone, a feature phone, a tablet, a wearable computer device, a Personal Digital Assistant (PDA), a pager, a wireless handset, a desktop computer, a laptop computer, an in-vehicle infotainment system (IVI), an in-vehicle entertainment (ICE) device, an Instrument panel (IC), a heads-up display (HUD) device, an in-vehicle diagnostics (OBD) device, a dashboard mobile Device (DME), a Mobile Data Terminal (MDT), an Electronic Engine Management System (EEMS), an electronic/Engine Control Unit (ECU), an electronic/Engine Control Module (ECM), an embedded system, a microcontroller, a control module, an Engine Management System (EMS), a networked or "smart" device, a Machine Type Communication (MTC) device, a machine-to-machine (M2M), an IoT (IoT) device, and/or the like.

In some embodiments, any of the UEs 101 may include an IoT UE, which may include a network access layer designed for low-power IoT applications that utilize short-term UE connections. IoT UEs may utilize technologies such as M2M or MTC to exchange data with MTC servers or devices via PLMNs, proximity-based services (ProSe) or device-to-device (D2D) communication, sensor networks, or IoT networks. The M2M or MTC data exchange may be a machine-initiated data exchange. IoT network descriptions interconnect IoT UEs that may include uniquely identifiable embedded computing devices (located within the internet infrastructure) using short-term connections. The IoT UE may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate connection of the IoT network.

UE101 may be configured to connect with (e.g., communicatively couple with) RAN 110. In an embodiment, RAN 110 may be a Next Generation (NG) RAN or a 5G RAN, an evolved Universal Mobile Telecommunications System (UMTS) terrestrial radio access network (E-UTRAN), or a legacy RAN, such as a UTRAN (UMTS terrestrial radio access network) or a GERAN (GSM (global system for Mobile communications or group Sp special Mobile) EDGE (GSM evolution) radio access network). As used herein, the term "NG RAN" or the like may refer to RAN 110 operating in an NR or 5G system 100, and the term "E-UTRAN" or the like may refer to RAN 110 operating in an LTE or 4G system 100. The UE101 utilizes connections (or channels) 103 and 104, respectively, each of which includes a physical communication interface or layer (discussed in further detail below). As used herein, the term "channel" may refer to any tangible or intangible transmission medium that communicates data or a stream of data. The term "channel" may be synonymous and/or equivalent to "communication channel," "data communication channel," "transmission channel," "data transmission channel," "access channel," "data access channel," "link," "data link," "carrier," "radio frequency carrier," and/or any other similar term denoting the path or medium through which data is communicated. In addition, the term "link" may refer to a connection between two devices for the purpose of transmitting and receiving information over a Radio Access Technology (RAT).

In this example,

connections

103 and 104 are shown as air interfaces for implementing communicative coupling, and may conform to a cellular communication protocol, such as a global system for mobile communications (GSM) protocol, a Code Division Multiple Access (CDMA) network protocol, a push-to-talk (PTT) protocol, a cellular PTT (POC) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a fifth generation (5G) protocol, a New Radio (NR) protocol, and/or any other communication protocol discussed herein. In an embodiment, the UE101 may exchange communication data directly via the ProSe interface 105. The ProSe interface 105 may alternatively be referred to as a Sidelink (SL) interface 105 and may include one or more logical channels including, but not limited to, a Physical Sidelink Control Channel (PSCCH), a physical sidelink shared channel (PSCCH), a Physical Sidelink Discovery Channel (PSDCH), and a Physical Sidelink Broadcast Channel (PSBCH).

UE101 b is shown configured to access an Access Point (AP) 106 (also referred to as "WLAN node 106", "WLAN terminal 106", or "WT106", etc.) via a connection 107. The connection 107 may comprise a local wireless connection, for example, a connection conforming to any IEEE 802.11 protocol, wherein the AP106 would comprise a wireless fidelity (WiFi) router. In this example, the AP106 is shown connected to the internet, not to the core network of the wireless system (described in further detail below). In various embodiments, UE101 b, RAN 110, and AP106 may be configured to utilize LTE-WLAN aggregation (LWA) operations and/or WLAN LTE/WLAN radio level integration (LWIP) operations with IPsec tunneling. LWA operation may involve UE101 b at RRC _ CONNECTED being configured by RAN node 111 to utilize radio resources of LTE and WLAN. The LWIP operation may involve the UE101 b using WLAN radio resources (e.g., the connection 107) via an internet protocol security (IPsec) protocol tunnel to authenticate and encrypt packets (e.g., internet Protocol (IP) packets) sent over the connection 107. An IPsec tunnel may involve encapsulating the entire original IP packet and adding a new packet header, thereby protecting the original header of the IP packet.

RAN 110 may include one or

more RAN nodes

111a and 111b (collectively "RAN nodes 111") that implement

connections

103 and 104. As used herein, the terms "Access Node (AN)", "access point", "RAN node", and the like may describe a device that provides radio baseband functionality for data and/or voice connections between a network and one or more users. These access nodes may be referred to as Base Stations (BSs), next generation node BS (gnbs), RAN nodes, evolved nodebs (enbs), nodebs, road Side Units (RSUs), transmit receive points (TRxP or TRP), etc., and may include ground stations (e.g., ground access points) or satellite stations that provide coverage within a geographic area (e.g., a cell). As used herein, the term "NG RAN node" or the like may refer to a RAN node 111 (e.g., a gNB) operating in the NR or 5G system 100, and the term "E-UTRAN node" or the like may refer to a RAN node 111 (e.g., an eNB) operating in the LTE or 4G system 100. According to various embodiments, the RAN node 111 may be implemented as one or more of the following: dedicated physical devices such as macrocell base stations, and/or Low Power (LP) base stations for providing femtocells, picocells or other similar cells with smaller coverage areas, smaller user capacities or higher bandwidths than macrocells.

In some embodiments, all or part of the RAN node 111 may be implemented as one or more software entities running on a server computer as part of a virtual network, which may be referred to as a Cloud Radio Access Network (CRAN) and/or a virtual baseband unit pool (vbbp). In these embodiments, the CRAN or vbbp may implement RAN functional partitioning, such as: PDCP partitioning, wherein RRC and PDCP layers are operated by the CRAN/vbbp, while other layer 2 (L2) protocol entities are operated by individual RAN nodes 111; MAC/PHY division, where RRC, PDCP, RLC and MAC layers are operated by the CRAN/vbup, and PHY layers are operated by individual RAN nodes 111; or "lower PHY" division, where the RRC, PDCP, RLC, MAC layers and upper parts of the PHY layers are operated by the CRAN/vbup and lower parts of the PHY layers are operated by the individual RAN node 111. The virtualization framework allows the vacated processor core of the RAN node 111 to execute other virtualized applications. In some implementations, the individual RAN nodes 111 may represent individual gNB-DUs that are connected to the gNB-CUs via individual F1 interfaces (not shown in fig. 1). In these implementations, the gNB-DUs may include one or more remote radio heads or radio front-end modules (RFEM), and the gNB-CUs may be operated by a server (not shown) located in the RAN 110 or by a server pool in a similar manner to the CRAN/vbbp. Additionally or alternatively, one or more of the RAN nodes 111 may be a next generation eNB (NG-eNB), which is a RAN node providing E-UTRA user plane and control plane protocol terminations towards the UE101 and which is connected to the 5GC via an NG interface.

In a V2X scenario, one or more of the RAN nodes 111 may be or act as RSUs. The term "roadside unit" or "RSU" may refer to any transportation infrastructure entity for V2X communication. The RSU may be implemented in or by a suitable RAN node or fixed (or relatively stationary) UE, where the RSU implemented in or by the UE may be referred to as a "UE-type RSU", the RSU implemented in or by the eNB may be referred to as an "eNB-type RSU", the RSU implemented in or by the gNB may be referred to as a "gNB-type RSU", and so on. In one example, the RSU is the following computing device: the computing device is coupled with radio frequency circuitry located at the curb that provides connectivity support to passing vehicular UEs 101 (vues 101). The RSU may also include internal data storage circuitry for storing intersection map geometry, traffic flow statistics, media, and applications/software for sensing and controlling ongoing vehicular and pedestrian traffic. The RSU may operate on the 5.9GHz Direct Short Range Communication (DSRC) band to provide very low latency communication required for high speed events, such as collision avoidance, traffic flow warnings, etc. Additionally or alternatively, the RSU may operate on the cellular V2X frequency band to provide the low latency communications described above, as well as other cellular communication services. Additionally or alternatively, the RSU may operate as a WiFi hotspot (2.4 GHz band) and/or provide a connection to one or more cellular networks to provide uplink and downlink communications. Some or all of the computing device(s) and radio frequency circuitry of the RSU may be enclosed in a weatherproof enclosure suitable for outdoor installation, and may include a network interface controller for providing wired connections (e.g., ethernet) to a traffic flow signal controller and/or a backhaul network.

Any of the RAN nodes 111 may terminate the air interface protocol and may be a first point of contact for the UE 101. In some embodiments, any of RAN nodes 111 may fulfill various logical functions of RAN 110, including but not limited to Radio Network Controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management.

In embodiments, UEs 101 may be configured to communicate with each other or with any of RAN nodes 111 over a multicarrier communication channel according to various communication techniques, such as, but not limited to, an Orthogonal Frequency Division Multiple Access (OFDMA) communication technique (e.g., for downlink communications) or a single-carrier frequency division multiple access (SC-FDMA) communication technique (e.g., for uplink and ProSe or sidelink communications), using Orthogonal Frequency Division Multiplexed (OFDM) communication signals, although the scope of the embodiments is not limited in this respect. The OFDM signal may include a plurality of orthogonal subcarriers.

In some embodiments, the downlink resource grid may be used for downlink transmissions from any RAN node 111 to the UE101, while uplink transmissions may use similar techniques. The grid may be a time-frequency grid, referred to as a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot. Such a time-frequency plane representation is common practice for OFDM systems, which makes radio resource allocation intuitive. Each column and each row of the resource grid corresponds to one OFDM symbol and one OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one time slot in a radio frame. The smallest time-frequency unit in the resource grid is represented as a resource element. Each resource grid includes a plurality of resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block comprises a set of resource elements; in the frequency domain, this may represent the minimum amount of resources that can currently be allocated. There are several different physical downlink channels transmitted using such resource blocks.

According to various embodiments, UE101 and RAN node 111 communicate (e.g., transmit and receive) data over a licensed medium (also referred to as "licensed spectrum" and/or "licensed band") and an unlicensed shared medium (also referred to as "unlicensed spectrum and/or" unlicensed band "). The licensed spectrum may include channels operating in a frequency range of about 400MHz to about 3.8GHz, while the unlicensed spectrum may include a 5GHz band.

To operate in unlicensed spectrum, the UE101 and RAN node 111 may operate using Licensed Assisted Access (LAA), enhanced LAA (eLAA), and/or other eLAA (feLAA) mechanisms. In these implementations, UE101 and RAN node 111 may perform one or more known medium sensing operations and/or carrier sensing operations to determine whether one or more channels in the unlicensed spectrum are unavailable or otherwise occupied prior to transmitting in the unlicensed spectrum. The medium/carrier sensing operation may be performed according to a Listen Before Talk (LBT) protocol.

LBT is the following mechanism: with this mechanism, a device (e.g., UE101, RAN node 111,112, etc.) senses the medium (e.g., channel or carrier frequency) and transmits when the medium is sensed to be idle (or when a particular channel in the medium is sensed to be unoccupied). The medium sensing operation may include Clear Channel Assessment (CCA) that utilizes at least Energy Detection (ED) to determine whether other signals are present on the channel to determine whether the channel is occupied or clear. The LBT mechanism allows the cellular/LAA network to coexist with incumbent systems in unlicensed spectrum and with other LAA networks. ED may include sensing Radio Frequency (RF) energy over an expected transmission band for a period of time and comparing the sensed RF energy to a predetermined or configured threshold.

Generally, an incumbent system in the 5GHz band is a WLAN based on IEEE 802.11 technology. WLANs employ a contention-based channel access mechanism known as carrier sense multiple access with collision avoidance (CSMA/CA). Here, when a WLAN node (e.g., a Mobile Station (MS) such as UE101, AP106, etc.) intends to transmit, the WLAN node may first perform a CCA prior to transmission. In addition, the backoff mechanism is used to avoid collisions in the following cases: more than one WLAN node senses the channel as idle and transmits simultaneously. The back-off mechanism may be a counter drawn randomly within the Contention Window Size (CWS) that is exponentially increased when collisions occur and reset to a minimum value when the transmission is successful. The LBT mechanism designed for LAA is somewhat similar to CSMA/CA of WLAN. In some implementations, an LBT procedure for a DL or UL transmission burst including a PDSCH or PUSCH transmission, respectively, may have an LAA contention window of variable length between X and Y extended CCA (ECCA) slots, where X and Y are minimum and maximum values of a CWS for the LAA. In one example, the minimum CWS for LAA transmission may be 9 microseconds (μ β); however, the size of the CWS and the Maximum Channel Occupancy Time (MCOT) (e.g., transmission bursts) may be based on government regulatory requirements.

The LAA mechanism is established based on the Carrier Aggregation (CA) technique of the LTE-Advanced system. In CA, each aggregated carrier is referred to as a Component Carrier (CC). The CCs may have bandwidths of 1.4, 3, 5, 10, 15, or 20MHz, and up to five CCs may be aggregated, and thus, the maximum aggregated bandwidth is 100MHz. In a Frequency Division Duplex (FDD) system, the number of aggregated carriers may be different for DL and UL, where the number of UL CCs is equal to or lower than the number of DL component carriers. In some cases, individual CCs may have different bandwidths than other CCs. In a Time Division Duplex (TDD) system, the number of CCs and the bandwidth of each CC are typically the same for DL and UL.

The CA also includes individual serving cells to provide individual CCs. The coverage of the serving cell may be different, e.g., because CCs on different frequency bands will experience different path losses. A primary serving cell or primary cell (PCell) may provide a primary CC (PCC) for both UL and DL and may handle Radio Resource Control (RRC) and non-access stratum (NAS) related activities. The other serving cells are referred to as secondary cells (scells), and each SCell may provide a separate secondary CC (SCC) for both UL and DL. SCCs may be added and removed as needed, while changing the PCC may require the UE101 to undergo handover. In LAA, eLAA, and feLAA, some or all scells may operate in unlicensed spectrum (referred to as "LAA scells"), and the LAA scells are assisted by pcells operating in licensed spectrum. When a UE is configured with more than one LAA SCell, the UE may receive a UL grant on the configured LAA SCell, the UL grant indicating different Physical Uplink Shared Channel (PUSCH) starting positions within the same subframe.

The Physical Downlink Shared Channel (PDSCH) may carry user data and higher layer signaling to the UE 101. A Physical Downlink Control Channel (PDCCH) may carry information about a transport format and resource allocation related to a PDSCH channel, and the like. It may also inform the UE101 of transport format, resource allocation and H-ARQ (hybrid automatic repeat request) information related to the uplink shared channel. In general, downlink scheduling (allocation of control and shared channel resource blocks to UEs 101b within a cell) may be performed at any one of RAN nodes 111 based on channel quality information fed back from any one of UEs 101. The downlink resource allocation information may be sent on a PDCCH for (e.g., allocated to) each UE 101.

The PDCCH may use Control Channel Elements (CCEs) to convey control information. The PDCCH complex-valued symbols may first be organized into quadruplets before mapping to resource elements, and then the quadruplets may be permuted using a sub-block interleaver for rate matching. Each PDCCH may be transmitted using one or more of these CCEs, where each CCE may correspond to nine sets of four physical resource elements called Resource Element Groups (REGs). Four Quadrature Phase Shift Keying (QPSK) symbols may be mapped to each REG. The PDCCH may be transmitted using one or more CCEs, depending on the size of Downlink Control Information (DCI) and channel conditions. There may be four or more different PDCCH formats (e.g., aggregation levels, L =1, 2, 4, or 8) defined in LTE with different numbers of CCEs.

Some embodiments may use the concept of resource allocation for control channel information, which is an extension of the above-described concept. For example, some embodiments may use an Enhanced Physical Downlink Control Channel (EPDCCH) that uses PDSCH resources for control information transmission. The EPDCCH may be transmitted using one or more Enhanced Control Channel Elements (ECCEs). Similar to the above, each ECCE may correspond to nine sets of four physical resource elements referred to as Enhanced Resource Element Groups (EREGs). In some cases, ECCE may have other numbers of EREGs.

The RAN nodes 111 may be configured to communicate with each other via an interface 112. In embodiments where system 100 is an LTE system, interface 112 may be an X2 interface 112. An X2 interface may be defined between two or more RAN nodes 111 (e.g., two or more enbs, etc.) connected to the EPC 120 and/or between two enbs connected to the EPC 120. In some implementations, the X2 interface may include an X2 user plane interface (X2-U) and an X2 control plane interface (X2-C). The X2-U may provide a flow control mechanism for user data packets transmitted over the X2 interface and may be used to communicate information about user data transfer between enbs. For example, X2-U may provide: specific sequence number information for user data transferred from a master eNB (MeNB) to a secondary eNB (SeNB); information on successful in-order transmission of PDCP PDUs for user data from the SeNB to the UE 101; information that PDCP PDUs are not delivered to the UE 101; information on the current minimum desired buffer size at the SeNB for transmitting user data to the UE, and the like. X2-C may provide intra-LTE access mobility functions including context transfer from source eNB to target eNB, user plane transfer control, etc.; a load management function; and an inter-cell interference coordination function.

In embodiments where system 100 is a 5G or NR system, interface 112 may be an Xn interface 112. An Xn interface is defined between two or more RAN nodes 111 (e.g., two or more gnbs, etc.) connected to the 5GC 120, between a RAN node 111 (e.g., a gNB) connected to the 5GC 120 and an eNB, and/or between two enbs connected to the 5GC 120. In some implementations, the Xn interface can include an Xn user plane (Xn-U) interface and an Xn control plane (Xn-C) interface. The Xn-U can provide unsecured delivery of user plane PDUs and support/provide data forwarding and flow control functionality. Xn-C can provide: management and error handling functions; managing the function of the Xn-C interface; mobility support for a UE101 in CONNECTED mode (e.g., CM-CONNECTED) includes functionality for managing UE mobility for CONNECTED mode between one or more RAN nodes 111. Mobility support may include: context transfer from the old (source) serving RAN node 111 to the new (target) serving RAN node 111; and control of user plane tunnels between the old (source) serving RAN node 111 and the new (target) serving RAN node 111. The protocol stack of the Xn-U may include a transport network layer established above an Internet Protocol (IP) transport layer and a GTP-U layer above UDP(s) and/or IP layers for carrying user plane PDUs. The Xn-C protocol stack may include an application layer signaling protocol, referred to as the Xn application protocol (Xn-AP), and a transport network layer built over SCTP. SCTP can be located above the IP layer and can provide guaranteed delivery of application layer messages. In the transport IP layer, point-to-point transport is used to deliver signaling PDUs. In other implementations, the Xn-U protocol stack and/or the Xn-C protocol stack may be the same as or similar to the user plane and/or control plane protocol stack(s) shown and described herein.

RAN 110 is shown communicatively coupled to a core network, in this embodiment, a Core Network (CN) 120.CN 120 may include a plurality of network elements 122 configured to provide various data and telecommunications services to customers/subscribers (e.g., users of UE 101) connected to CN 120 through RAN 110. The term "network element" may describe a physical or virtualized device used to provide wired or wireless communication network services. The term "network element" may be considered synonymous with and/or referred to as: a networking computer, network hardware, network device, router, switch, hub, bridge, radio network controller, radio access network device, gateway, server, virtualized Network Function (VNF), network Function Virtualization Infrastructure (NFVI), and/or the like. The components of CN 120 may be implemented in one physical node or separate physical nodes, including components that read and execute instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium). In some embodiments, network Function Virtualization (NFV) may be used to virtualize any or all of the above network node functions via executable instructions stored in one or more computer-readable storage media (described in further detail below). Logical instantiations of the CN 120 may be referred to as network slices, and logical instantiations of a portion of the CN 120 may be referred to as network subslices. The NFV architecture and infrastructure may be used to virtualize one or more network functions on physical resources, which may alternatively be performed by dedicated hardware, including a combination of industry standard server hardware, storage hardware, or switches. In other words, the NFV system may be used to perform a virtual or reconfigurable implementation of one or more EPC components/functions.

In general, the application server 130 may be an element that provides applications that use IP bearer resources with a core network (e.g., UMTS Packet Service (PS) domain, LTE PS data services, etc.). The application server 130 may also be configured to support one or more communication services (e.g., voice over internet protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UE101 via the EPC 120.

In an embodiment, the CN 120 may be a 5GC (referred to as "5GC 120," etc.), and the RAN 110 may be connected with the CN 120 via the NG interface 113. In an embodiment, the NG interface 113 may be divided into two parts: NG user plane (NG-U) interface 114, and S1 control plane (NG-C) interface 115, NG user plane (NG-U) interface 114 carrying traffic data between RAN node 111 and User Plane Functions (UPFs), and S1 control plane (NG-C) interface 115 being a signaling interface between RAN node 111 and AMFs.

In embodiments, CN 120 may be a 5G CN (referred to as "5GC 120," etc.), while in other embodiments, CN 120 may be an Evolved Packet Core (EPC). In the case where CN 120 is an EPC (referred to as "EPC 120," etc.), RAN 110 may connect with CN 120 via S1 interface 113. In an embodiment, the S1 interface 13 may be divided into two parts: an S1 user plane (S1-U) interface 114, and an S1-Mobility Management Entity (MME) interface 115, the S1 user plane (S1-U) interface 114 carrying traffic data between the RAN node 111 and the serving gateway (S-GW), the S1-Mobility Management Entity (MME) interface 115 being a signaling interface between the RAN node 111 and the MME.

Fig. 2 illustrates an example architecture of a system 200 including a 5GC 220, according to some embodiments of the present disclosure.

The system 200 is shown as including: a UE 201, which may be the same as or similar to the UE101 previously discussed; (R) AN 210, which may be the same as or similar to RAN 110 discussed previously, and which may include RAN node 111 discussed previously; and a Data Network (DN) 203, which may be, for example, an operator service, internet access, or third party service; and a 5G core network (5 GC or CN) 220.

The 5GC 220 may include an authentication server function (AUSF) 222; an access and mobility management function (AMF) 221; a Session Management Function (SMF) 224; a Network Exposure Function (NEF) 223; a Policy Control Function (PCF) 226; a Network Function (NF) repository function (NRF) 225; unified Data Management (UDM) 227; an Application Function (AF) 228; a User Plane Function (UPF) 202; and a Network Slice Selection Function (NSSF) 229.

The UPF 202 may serve as an anchor point for intra-RAT and inter-RAT mobility, an external PDU session interconnect point to the DN 203, and a branch point to support multi-homed PDU sessions. The UPF 202 may also perform packet routing and forwarding, packet inspection, perform policy rules for the user plane part, lawful intercept packets (UP set), traffic usage reporting, perform QoS processing on the user plane (e.g., packet filtering, gating, UL/DL rate enforcement), perform uplink traffic verification (e.g., SDF to QoS traffic mapping), transport level packet marking in uplink and downlink, and downlink packet buffering and downlink data notification triggering. The UPF 202 may include an uplink classifier to support routing of traffic flows to a data network. DN 203 may represent various network operator services, internet access, or third party services. DN 203 may include or be similar to application server 130 previously discussed. The UPF 202 may interact with the SMF 224 via an N4 reference point between the SMF 224 and the UPF 202.

The AUSF 222 may store data for authentication of the UE 201 and process authentication related functions. The AUSF 222 may facilitate a common authentication framework for various access types. The AUSF 222 may communicate with the AMF 221 via an N12 reference point between the AMF 221 and the AUSF 222; and may communicate with UDM 227 via an N13 reference point between UDM 227 and AUSF 222. Further, the AUSF 222 may present a Nausf service based interface.

The AMF 221 may be responsible for registration management (e.g., for registering the UE 201, etc.), connection management, reachability management, mobility management, and lawful interception of AMF-related events, as well as access authentication and authorization. The AMF 221 may be a termination point of the N11 reference point between the AMF 221 and the SMF 224. The AMF 221 may provide transport for Session Management (SM) messages between the UE 201 and the SMF 224 and act as a transparent proxy for routing SM messages. The AMF 221 may also provide for transmission of Short Message Service (SMS) messages between the UE 201 and an SMS function (SMSF) (not shown in fig. 2). The AMF 221 may act as a security anchor function (SEA), which may include interacting with the AUSF 222 and the UE 201, receiving intermediate keys established as a result of the UE 201 authentication procedure. In the case where USIM-based authentication is used, the AMF 221 may retrieve security materials from the AUSF 222. The AMF 221 may also include a Security Context Management (SCM) function that receives a key from the SEA, which it uses to derive an access network-specific key. Further, the AMF 221 may be a termination point of a RAN CP interface, which may include or be AN N2 reference point between the (R) AN 211 and the AMF 221; the AMF 221 may be a termination point of NAS (N1) signaling and performs NAS ciphering and integrity protection.

The AMF 221 may also support NAS signaling with the UE 201 through an N3 interworking function (IWF) interface. The N3IWF may be used to provide access to untrusted entities. The N3IWF may be a termination point for the N2 interface between the (R) AN 210 and the AMF 221 of the control plane and may be a termination point for the N3 reference point between the (R) AN 210 and the UPF 202 of the user plane. In this way, AMF 221 may process N2 signaling from SMF 224 and AMF 221 for PDU session and QoS processing, encapsulate/decapsulate packets for IPSec and N3 tunnels, label N3 user plane packets in the uplink, and implement a QoS corresponding to N3 packet labeling that takes into account QoS requirements associated with such labeling received over N2. The N3IWF may also relay uplink and downlink control plane NAS signaling between UE 201 and AMF 221 via the N1 reference point between UE 201 and AMF 221, and uplink and downlink user plane packets between UE 201 and UPF 202. The N3IWF also provides a mechanism to establish an IPsec tunnel with the UE 201. The AMF 221 may present a Namf service based interface and may be a termination point for an N14 reference point between two AMFs 221 and an N17 reference point between the AMF 221 and a 5G device identification register (5G-EIR) (not shown in fig. 2).

The UE 201 may need to register with the AMF 221 to receive network services. The Registration Management (RM) is used to register or deregister the UE 201 with the network (e.g., the AMF 221) and establish a UE context in the network (e.g., the AMF 221). The UE 201 may operate in an RM registration state or an RM deregistration state. In the RM deregistered state, the UE 201 is not registered with the network and the UE context in the AMF 221 does not hold valid location or routing information for the UE 201, so the UE 201 is not reachable to the AMF 221. In the RM registration state, the UE 201 registers with the network and the UE context in the AMF 221 can maintain valid location or routing information of the UE 201, so the UE 201 is reachable to the AMF 221. In the RM registration state, the UE 201 may perform a mobility registration update procedure, perform a periodic registration update procedure triggered by the expiration of a periodic update timer (e.g., to inform the network that the UE 201 is still active), and perform a registration update procedure to update UE capability information or renegotiate protocol parameters with the network, etc.

The AMF 221 may store one or more RM contexts for the UE 201, where each RM context is associated with a particular access to the network. The RM context may be a data structure, database object, etc. that indicates or stores, for example, registration status and periodic update timers, etc. for each access type. The AMF 221 may also store a 5GC MM context, which may be the same as or similar to the (E) MM context previously discussed. In various embodiments, AMF 221 may store the CE mode B restriction parameters for UE 201 in the associated MM context or RM context. The AMF 221 may also derive the value from the setup parameters used by the UE that are already stored in the UE context (and/or MM/RM context) when needed.

The Connection Management (CM) may be used to establish and release a signaling connection between the UE 201 and the AMF 221 through the N1 interface. The signaling connection is used to enable NAS signaling exchange between the UE 201 and the CN 120 and includes AN Access Network (AN) signaling connection (e.g., RRC connection or UE-N3IWF connection for non-3 GPP) between the UE and the AN, and AN N2 connection for the UE 201 between the AN (e.g., RAN 210) and AMF 221. The UE 201 may operate in one of two CM states: a CM IDLE (CM-IDLE) mode or a CM CONNECTED (CM-CONNECTED) mode. When the UE 201 operates in the CM-IDLE state/mode, the UE 201 may not have a NAS signaling connection established with the AMF 221 over the N1 interface, and there may be AN (R) AN 210 signaling connection (e.g., N2 and/or N3 connection) for the UE 201. When the UE 201 operates in the CM-CONNECTED state/mode, the UE 201 may have a NAS signaling connection established with the AMF 221 over the N1 interface, and there may be AN (R) AN 210 signaling connection (e.g., N2 and/or N3 connection) for the UE 201. Establishing the N2 connection between the (R) AN 210 and the AMF 221 may cause the UE 201 to transition from the CM-IDLE mode to the CM-CONNECTED mode, and when N2 signaling between the (R) AN 210 and the AMF 221 is released, the UE 201 may transition from the CM-CONNECTED mode to the CM-IDLE mode.

The SMF 224 may be responsible for: session Management (SM) (e.g., session establishment, modification, and release, including tunnel maintenance between UPF and AN nodes); UE IP address assignment and management (including optional authorization); selecting and controlling the UP function; configuring traffic steering at the UPF to route traffic to the correct destination; termination of an interface towards a policy control function; controlling a portion of policy enforcement and QoS; lawful interception (for SM events and interface with LI system); termination of the SM part of the NAS message; a downlink data notification; initiating AN AN-specific SM information sent over N2 to the AN via the AMF; the SSC pattern for the session is determined. SM may refer to the management of a PDU session, which may refer to a PDU connection service that provides or enables the exchange of PDUs between the UE 201 and a Data Network (DN) 203 identified by a Data Network Name (DNN). The PDU session may be established according to the UE 201 request, modified according to the UE 201 and 5GC 220 requests, and released according to the UE 201 and 5GC 220 requests using NAS SM signaling exchanged over the N1 reference point between the UE 201 and the SMF 224. Upon request from the application server, the 5GC 220 may trigger a specific application in the UE 201. In response to receiving the trigger message, the UE 201 may communicate the trigger message (or a relevant portion/information of the trigger message) to one or more identified applications in the UE 201. The identified application(s) in the UE 201 may establish a PDU session to a particular DNN. The SMF 224 may check whether the UE 201 request conforms to the user subscription information associated with the UE 201. In this regard, the SMF 224 may retrieve and/or request to receive update notifications regarding SMF 224 level subscription data from the UDM 227.

The SMF 224 may include the following roaming functions: processing the local enforcement to apply a QoS SLA (VPLMN); a charging data collection and charging interface (VPLMN); lawful interception (in the interface of VPLMN and LI systems for SM events); interaction with the foreign DN is supported to transmit signaling of PDU session authorization/authentication through the foreign DN. An N16 reference point between two SMFs 224 may be included in the system 200, which may be located between another SMF 224 in the visited network and the SMF 224 in the home network in a roaming scenario. Further, the SMF 224 may present an Nsmf service based interface.

NEF 223 may provide a means for securely exposing services and capabilities provided by 3GPP network functionality to third parties, internal exposure/re-exposure, application functions (e.g., AF 228), edge computing or fog computing systems, and the like. In such embodiments, NEF 223 may authenticate, authorize, and/or restrict AF. NEF 223 may also translate information exchanged with AF 228 and information exchanged with internal network functions. For example, the NEF 223 may convert between the AF service identifier and the internal 5GC information. NEF 223 may also receive information from other Network Functions (NFs) based on their exposed capabilities. This information may be stored as structured data at the NEF 223 or at the data storage NF using a standardized interface. The stored information may then be re-exposed by the NEF 223 to other NFs and AFs, and/or used for other purposes, such as analysis. In addition, NEF 223 may present an interface based on the Nnef service.

NRF 225 may support a service discovery function, receive NF discovery requests from NF instances, and provide information of discovered NF instances to NF instances. NRF 225 also maintains information of available NF instances and the services it supports. As used herein, the term "instantiation" or the like may refer to the creation of an instance, and "instance" may refer to the specific occurrence of an object, which may occur, for example, during execution of program code. Further, NRF 225 may present an interface based on the Nnrf service.

PCF 226 may provide policy rules for controlling plane function(s) to enforce the plane functions and may also support a unified policy framework to manage network behavior. PCF 226 may also implement a Front End (FE) to access subscription information related to policy decisions in the UDR of UDM 227. PCF 226 may communicate with AMF 221 via an N15 reference point between PCF 226 and AMF 221, which may include PCF 226 and AMF 221 in a visited network in a roaming scenario. PCF 226 may communicate with AF 228 via an N5 reference point between PCF 226 and AF 228; the SMF 224 is communicated via an N7 reference point between the PCF 226 and the SMF 224. The system 200 and/or the CN 120 may also include an N24 reference point between the PCF 226 (in the home network) and the PCF 226 in the visited network. In addition, PCF 226 may present an interface based on Npcf services.

UDM 227 may process subscription related information to support processing of communication sessions by network entities and may store subscription data for UE 201. For example, subscription data may be transmitted between UDM 227 and AMF 221 over an N8 reference point (not shown in fig. 2) between UDM 227 and AMF 221. UDM 227 may include two parts: an application FE and a User Data Repository (UDR) (the FE and UDR are not shown in fig. 2). The UDR may store subscription data and policy data for UDM 227 and PCF 226, and/or structured data for exposure and application data for NEF 223 (including Packet Flow Description (PFD) for application detection, application request information for multiple UEs 201). UDR 221 may present an interface based on the nurr service to allow UDM 227, PCF 226, and NEF 223 to access a particular set of stored data, as well as read, update (e.g., add, modify), delete, and subscribe to notifications of relevant data changes in the UDR. The UDM may include a UDM FE that is responsible for credential handling, location management, subscription management, and the like. Several different front ends may serve the same user in different transactions. The UDM-FE accesses the subscription information stored in the UDR and executes authentication credential processing; user identification processing; access authorization; registration/mobility management; and subscription management. The UDR may interact with the SMF 224 via an N10 reference point between the UDM 227 and the SMF 224. UDM 227 may also support SMS management, where an SMS-FE implements similar application logic as previously described. Additionally, UDM 227 may present a numm service based interface.

The AF 228 can provide application impact on traffic routing, access Network Capability Exposure (NCE), and interact with the policy framework for policy control. The NCE may be a mechanism that allows the 5GC 220 and AF 228 to provide information to each other via the NEF 223, which may be used for edge computing implementations. In such implementations, network operator and third party services may be hosted near the UE 201 access connection point to achieve efficient service delivery with reduced end-to-end delay and load on the transport network. For edge computation implementations, the 5GC may select a UPF 202 close to the UE 201 and perform traffic steering from the UPF 202 to the DN 203 via the N6 interface. This may be based on UE subscription data, UE location and information provided by the AF 228. In this way, the AF 228 may affect UPF (re) selection and traffic routing. Based on operator deployment, the network operator may allow the AF 228 to interact directly with the relevant NFs when the AF 228 is considered a trusted entity. In addition, the AF 228 may expose a Naf service-based interface.

NSSF 229 may select a set of network slice instances that serve UE 201. NSSF 229 may also determine allowed Network Slice Selection Assistance Information (NSSAI) and a mapping to a single NSSAI (S-NSSAI) of the subscription, if needed. The NSSF 229 may also determine the set of AMFs, or list of candidate AMFs 221(s), for serving the UE 201 based on a suitable configuration and possibly by querying the NRF 225. The selection of a set of network slice instances for the UE 201 may be triggered by the AMF 221 with which the UE 201 is registered by interacting with the NSSF 229, which may result in a change in the AMF 221. NSSF 229 may interact with AMF 221 via an N22 reference point between AMF 221 and NSSF 229; and may communicate with another NSSF 229 in the visited network over an N31 reference point (not shown in figure 2). Additionally, NSSF 229 may present an interface based on the NSSF service.

As previously described, the 5GC 220 may include an SMSF, which may be responsible for SMS subscription checking and verification, and relaying SM messages to/from the UE 201 from/to other entities, such as SMS-GMSC/IWMSC/SMS routers. The SMS may also interact with AMF 221 and UDM 227 to perform notification procedures that UE 201 may use for SMS delivery (e.g., set a UE unreachable flag, and notify UDM 227 when UE 201 is available for SMS).

The 5GC 220 may also include other elements not shown in fig. 2, such as a data storage system/architecture, 5G device identity registers (5G-EIR), secure Edge Protection Proxies (SEPP), and so forth. The data storage system may include a structured data storage network function (SDSF), an unstructured data storage network function (UDSF), and the like. Any NF may store unstructured data (e.g., UE context) into or retrieve unstructured data from the UDSF via an N18 reference point (not shown in fig. 2) between any NF and the UDSF. The individual NFs may share the UDSF to store their respective unstructured data, or the individual NFs may each have their own UDSF located at or near the individual NFs. Additionally, the UDSF may present a Nudsf service based interface (not shown in fig. 2). The 5G-EIR may be the following NF: it checks the status of the permanent device identifier (PEI) to determine if a particular device/entity is blacklisted on the network; the SEPP may be a non-transparent proxy that performs topology hiding, message filtering and policing on the inter-PLMN control plane interface.

Additionally, there may be more reference points and/or service-based interfaces between NF services in an NF; however, these interfaces and reference points are omitted from FIG. 2 for clarity. In one example, the 5GC 220 may include an Nx interface, which is an inter-CN interface between the MME and the AMF 221 for implementing interworking between the EPC and the 5GC 220. Other example interfaces/references these points may include an N5G-EIR service based interface demonstrated by 5G-EIR, an N27 reference point between the NRF in the visited network and the NRF in the home network; and an N31 reference point between the NSSF in the visited network and the NSSF in the home network.

The 5GC 220 may include a Location Management Function (LMF) (not shown in fig. 2) that may communicate with the (R) AN 210 and/or the UE 201 via the AMF 221. The LMF may manage support for different location services for target UEs (e.g., UE101 and UE 201), including positioning of the UEs and communicating assistance data to the UEs. The LMF may interact with a serving gNB (e.g., (R) AN 210) for the target UE to obtain location measurements and/or positioning-related information for the UE, including uplink measurements by the gNB and downlink measurements by the UE (which are provided to the gNB). The LMF may interact with the target UE to communicate assistance data when requesting a particular location service or to obtain a location estimate when requesting a location estimate.

NRPPa is a protocol used between the gNB and LMF for transmitting configuration information (e.g., for Downlink (DL) positioning methods) and positioning measurements and configuration results (e.g., for Uplink (UL) positioning methods). In some embodiments of the present disclosure, "positioning" and "location" may be interchanged. The procedure related to the configuration information exchange and the procedure related to the location measurement will be described in detail below.

Hereinafter, the present application will be described with respect to a cell Transmission Reception Point (TRP) of a user equipment (UE, e.g., UE101 a or UE101 b in fig. 1, or UE 201 in fig. 2) and a base station (e.g., RAN, e.g., RAN 110 in fig. 1 or (R) AN 210 in fig. 2, particularly, a gNB (next generation NodeB)). In particular, the present application will be described mainly from the UE side. It will be appreciated that the operation of the respective TRPs or base stations interacting with the described UE will improve accordingly.

In particular, the present application is directed to portions of the 3GPP NR Rel-17 (V16.5.0 (2021-06)) work related to supporting enhanced MIMO beam management.

In Rel-15 and Rel-16 NR, UE cross-cell mobility is handled by a higher layer cell handover procedure that uses filtered layer 3 (L3) RSRP measurements to determine the handover point. However, conventional cell handover procedures are typically slow and result in long measurement and interruption times. In the Rel-17 NR MIMO work item, new L1-L2 based mobility is considered, where the UE can switch beams to non-serving cell TRPs or TRPs with different physical cell IDs without the need for higher layer cell switching procedures. In this application, the handover procedure is based on the Rel-17 unified TCI framework.

As shown in fig. 3, an apparatus 300 for handing over a UE between cell TRPs according to the present application includes a processor 310 and an interface 320 coupled to each other.

The processor 310 is configured to: detecting L1 parameter values of a plurality of non-serving cell TRPs for a UE; determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value; and handing over the UE to one of the at least one candidate serving cell TRP.

The processor 310 may be any processing unit that may perform operations according to embodiments of the application, for example, a processor in or configured for a UE. In other words, the processor 310 may perform the following operations as described below: the operations may be operations corresponding to the steps of a method for handover of a UE between cell TRPs according to an embodiment of the present application.

In this case, for convenience of description, operations performed by the processor 310 will be described below in conjunction with at least one flowchart of a method for handing over a UE between cell TRPs according to an embodiment of the present application. In other words, the processor 310 cooperates with the interface 320 to perform the following processes.

As shown in fig. 4, L1 parameter values of a plurality of non-serving cell TRPs for a UE are detected (e.g., by the processor 310) in step S410. For example, L1 parameter values of K non-serving cell TRPs for a UE may be detected. The value K may be any value determined according to actual needs.

In one embodiment, the processor 310 may periodically detect the L1 parameter value of each of the plurality of non-serving cell TRPs in step S410.

The L1 parameter value here may be a parameter value obtained by performing L1 measurement on a beam from the non-serving cell TRP.

In one embodiment, the L1 parameter value may include a L1RSRP measurement value for a configured TCI state corresponding to each of the plurality of non-serving cell TRPs.

In this case, in one embodiment, the L1 parameter value may be a single short L1RSRP measurement value or a filtered L1RSRP measurement value.

In one embodiment, the filtered L1RSRP measurement may be a temporally filtered version of the L1RSRP measurement, or a spatially filtered version of the L1RSRP measurement, e.g., a filtered version of all UE Rx beams.

In step 420, at least one candidate serving cell TRP of the plurality of non-serving cell TRPs is determined (e.g., by processor 310) based on the L1 parameter value.

In one embodiment, the processor 310 may determine a non-serving cell TRP having an L1 parameter value higher than a first predetermined threshold among the plurality of non-serving cell TRPs as a candidate serving cell TRP.

For example, the first predetermined threshold may be any value predefined according to actual needs.

In another embodiment, the processor 310 may determine a non-serving cell TRP having the following L1 parameter value among the plurality of non-serving cell TRPs as a candidate serving cell TRP: the L1 parameter value is higher than a current L1 parameter value of a current serving cell TRP of the UE by more than a second predetermined threshold.

For example, where the L1 parameter values may comprise L1RSRP measurement values, the second predetermined threshold may be 3dB, or may be other values depending on actual needs.

In yet another embodiment, the processor 310 may determine a non-serving cell TRP among the plurality of non-serving cell TRPs having the following L1 parameter value as a candidate serving cell TRP: the L1 parameter value is higher than both the current L1 parameter value of the current serving cell TRP of the UE and the other L1 parameter values of the other serving cells TRP of the UE.

In any of the above cases, the at least one candidate serving cell TRP determined in step S420 may include all of the plurality of non-serving cell TRPs, or in other words, all of the plurality of non-serving cell TRPs may be determined as candidate serving cell TRPs.

In step S430, the UE is handed over to one of the at least one candidate serving cell TRP.

Fig. 5 shows a flowchart of an example of a handover step S430 in a method for handing over a UE between cell TRPs according to an embodiment of the present disclosure.

Referring to fig. 5, in step S431, a Scheduling Request (SR) is generated (e.g., by the processor 310).

In one embodiment, the SR may have a priority higher than that of an SR for UL scheduling from a higher layer and lower than that of an SR for BFR, i.e., a Link Restoration Request (LRR).

In step S432, the SR is transmitted (e.g., by the processor 310 via the interface 320) to the current serving cell TRP through the PUCCH periodically scheduled by the current serving cell TRP of the UE.

In step S433, an L1 parameter report request in response to the SR is received from the current serving cell TRP (e.g., by the processor 310 via the interface 320).

In one embodiment, the L1 parameter report request may be sent by the current serving cell TRP in a semi-static or aperiodic manner.

In step S434, an L1 parameter report is generated (e.g., by the processor 310) in response to the L1 parameter report request.

In one embodiment, the generated L1 parameter report may include L1 parameter values of a plurality of non-serving cell TRPs or include L1 parameter values of at least one candidate serving cell TRP. Further, in one embodiment, the L1 parameter report may also include an RS indicator associated with each L1 parameter value.

In step S435, an L1 parameter report is sent to the current serving cell TRP (e.g., by the processor 310 via the interface 320).

In one embodiment, the L1 parameter report may be sent to the current serving cell TRP on the UCI in a CSI report instance (instance).

In one embodiment, the L1 parameter report may be transmitted to the current serving cell TRP through a PUSCH scheduled by the current serving cell TRP by using MAC-CE.

In step S436, the UE may be handed over to one of the at least one candidate serving cell TRP indicated by the base station (e.g., the current serving base station) that received the L1 parameter report from the current serving cell TRP.

In one embodiment, the one of the at least one candidate serving cell TRP may be the candidate serving cell TRP having the best detected L1 parameter value, wherein the L1 parameter value corresponds to the TCI status associated with the candidate serving cell TRP.

In this case, in one embodiment, the TCI state associated with the candidate serving cell TRP may be one of a DL TCI state, an UL TCI state, and a joint DL/UL TCI state.

As shown in fig. 6, the UE is a mobile UE, and in step S610, the current serving cell TRP (current serving base station) may configure a periodic PUCCH resource for L1/L2 mobility purposes (i.e., for the above-described SR) and inform the UE of this configuration. In other words, when the UE determines that a condition (i.e., an event trigger criterion) for generating the SR is satisfied (e.g., when at least one candidate serving cell TRP is determined among a plurality of non-serving cell TRPs (e.g., K non-serving cell TRPs), or when all non-serving cell TRPs among the K non-serving cell TRPs are determined as candidate serving cell TRPs), the UE desires to transmit the PUCCH-SR (i.e., the above-described SR) in the configured periodic PUCCH resource.

In step S620, the UE may perform L1 measurement on beams from the K non-serving cell TRPs to obtain L1 parameter values (which correspond to TCI states associated with the K non-serving cell TRPs) of the K non-serving cell TRPs.

The UE may then determine whether event triggering criteria are met, e.g. whether at least one candidate serving cell TRP for handover is determined among the K non-serving cell TRPs. For example, as described above, the candidate serving cell TRP may be at least one of: a non-serving cell TRP having an L1 parameter value higher than the current L1 parameter value of the current serving cell TRP of the UE by more than a second predetermined threshold (e.g., X dB), as shown in fig. 6, a non-serving cell TRP having an L1 parameter value higher than the first predetermined threshold, and a non-serving cell TRP having an L1 parameter value higher than the current L1 parameter value of the current serving cell TRP of the UE and other L1 parameter values of all other serving cells TRP of the UE.

In the example shown in fig. 6, to determine the candidate serving cell TRP, the UE may compare the L1 parameter value (L1-RSRP in fig. 6) for the beam from each non-serving cell TRP (shown by the block following the first block on the left in fig. 6) with the L1 parameter value of the beam from the current serving cell TRP (shown by the first block on the left in fig. 6), and may determine the non-serving cell TRP as the candidate serving cell TRP if the difference between them is higher than X dB (e.g., 3dB in the above example).

After the UE determines that the event trigger criteria are satisfied, the UE may generate a PUCCH (SR) and transmit the PUCCH (SR) to the current serving cell TRP on the dedicated L1/L2 mobility PUCCH configured in S610 in step S630.

In step S640, the current serving cell TRP may trigger an L1-RSRP report request (i.e., the above-described L1 parameter report request) in response to the SR and transmit the L1-RSRP report request to the UE.

In step S650, the UE may generate an L1-RSPR report (i.e., the above-described L1 parameter report) in response to the L1-RSRP report request, and transmit the L1-RSPR report to the current serving cell TRP in a CSI report instance on UCI. For example, the L-RSPR report may include all the L1 measurement values of the K non-serving cell TRPs, or include only the L1 measurement values of the determined candidate serving cell TRPs among the K non-serving cell TRPs.

In step S660, the current serving base station may activate a selected candidate serving cell TRP and indicate the selected candidate serving cell TRP to the UE via DCI/MAC-CE for handover of the UE. For example, the candidate serving cell TRP with the best L1 parameter value may be selected, or the selection may depend on the network implementation of the base station.

The UE may then switch to the candidate serving cell TRP indicated by the base station.

According to the method and apparatus for switching the UE between the cell TRPs of the embodiments of the present application, the UE can be switched from the current serving cell TRP to one of the non-serving cell TRPs based on the L1 parameter value measured by the UE instead of based on higher layer measurement, so that the switching efficiency can be improved, and the measurement and interruption time for the switching can be reduced.

Fig. 7 shows a diagram of a network 700, according to various embodiments of the present disclosure. The network 700 may operate in a manner consistent with the 3GPP technical specifications for LTE or 5G/NR systems. However, the example embodiments are not limited in this respect and the described embodiments may be applied to other networks, such as future 3GPP systems and the like, which benefit from the principles described herein.

Network 700 may include a UE 702, which may include any mobile or non-mobile computing device designed to communicate with RAN 704 via an over-the-air connection. The UE 702 may be, but is not limited to, a smartphone, a tablet, a wearable computer device, a desktop computer, a laptop computer, an in-vehicle infotainment device, an in-vehicle entertainment device, an instrument cluster, a heads-up display device, an in-vehicle diagnostic device, a dashboard mobile device, a mobile data terminal, an electronic engine management system, an electronic/engine control unit, an electronic/engine control module, an embedded system, a sensor, a microcontroller, a control module, an engine management system, a networked appliance, a machine-type communication device, an M2M or D2D device, an internet of things device, and/or the like.

In some embodiments, the network 700 may include multiple UEs directly coupled to each other through edge link interfaces. The UE may be an M2M/D2D device that communicates using a physical side link channel (e.g., without limitation, a physical side link broadcast channel (PSBCH), a physical side link discovery channel (PSDCH), a physical side link shared channel (PSSCH), a physical side link control channel (PSCCH), a physical side link basic channel (PSFCH), etc.).

In some embodiments, the UE 702 may also communicate with the AP 706 over an over-the-air connection. The AP 706 may manage WLAN connections that may be used to offload some/all network traffic from the RAN 704. The connection between the UE 702 and the AP 706 may be in accordance with any IEEE 802.11 protocol, wherein the AP 706 may be wireless fidelity (WiFi)

A router. In some embodiments, the UE 702, RAN 704, and AP 706 may utilize cellular WLAN aggregation (e.g., LTE-WLAN aggregation (LWA)/lightweight IP (LWIP)). Cellular WLAN aggregation may involve a UE 702 configured by a RAN 704 to utilize both cellular radio resources and WLAN resources.

RAN 704 may include one or more access nodes, e.g., AN 708. The AN 708 may terminate the air interface protocols of the UE 702 by providing access stratum protocols including RRC, packet Data Convergence Protocol (PDCP), radio Link Control (RLC), medium Access Control (MAC), and L1 protocols. In this manner, the AN 708 may enable data/voice connectivity between the CN 720 and the UE 702. In some embodiments, AN 708 may be implemented in a separate device or as one or more software entities running on a server computer, as part of a virtual network, for example, which may be referred to as a CRAN or virtual baseband unit pool. AN 708 may be referred to as a Base Station (BS), a gNB, a RAN node, AN evolved node B (eNB), a next generation eNB (ng-eNB), a node B (NodeB), a roadside unit (RSU), a TRxP, a TRP, and so on. The AN 708 can be a macrocell base station or a low power base station that provides a microcell, picocell, or other similar cell with a smaller coverage area, smaller user capacity, or higher bandwidth than a macrocell.

In embodiments where the RAN 704 comprises multiple ANs, they may be coupled to each other over AN X2 interface (in the case where the RAN 704 is AN LTE RAN) or AN Xn interface (in the case where the RAN 704 is a 5G RAN). The X2/Xn interface, which in some embodiments may be separated into a control plane interface/user plane interface, may allow the AN to communicate information related to handover, data/context transfer, mobility, load management, interference coordination, etc.

The ANs of RAN 704 may each manage one or more cells, groups of cells, component carriers, etc., to provide UE 702 with AN air interface for network access. The UE 702 may be simultaneously connected with multiple cells provided by the same or different ANs of the RAN 704. For example, the UE 702 and the RAN 704 may use carrier aggregation to allow the UE 702 to connect with multiple component carriers, each corresponding to a primary cell (Pcell) or a secondary cell (Scell). In a dual connectivity scenario, a first AN may be a master node providing a Master Cell Group (MCG) and a second AN may be a secondary node providing a Secondary Cell Group (SCG). The first/second AN can be any combination of eNB, gNB, ng-eNB, etc.

RAN 704 may provide an air interface over a licensed spectrum or an unlicensed spectrum. To operate in unlicensed spectrum, a node may use a Licensed Assisted Access (LAA), enhanced LAA (eLAA), and/or further enhanced LAA (feLAA) mechanism based on Carrier Aggregation (CA) technology with PCell/Scell. Prior to accessing the unlicensed spectrum, the node may perform a media/carrier sensing operation based on, for example, a Listen Before Talk (LBT) protocol.

In a vehicle-to-everything (V2X) scenario, the UE 702 or AN 708 may be or act as a Road Side Unit (RSU), which may refer to any transport infrastructure entity for V2X communication. The RSU may be implemented in or by AN appropriate AN or stationary (or relatively stationary) UE. An RSU implemented in or by a UE may be referred to as a "UE-type RSU"; an RSU implemented in or by an eNB may be referred to as an "eNB-type RSU"; RSUs implemented in or by a next generation NodeB (gNB) may be referred to as "gNB-type RSUs"; and so on. In one example, the RSU is a computing device coupled with radio frequency circuitry located at the curb side that provides connectivity support to passing vehicle UEs. The RSU may also include internal data storage circuitry for storing intersection map geometry, traffic statistics, media, and applications/software for sensing and controlling ongoing vehicle and pedestrian traffic. The RSU may provide very low latency communications required for high speed events, e.g., collision avoidance, traffic warnings, etc. Additionally or alternatively, the RSU may provide other cellular/WLAN communication services. The components of the RSU may be enclosed in a weatherproof enclosure suitable for outdoor installation and may include a network interface controller to provide a wired connection (e.g., ethernet) to a traffic signal controller or backhaul network.

In some embodiments, RAN 704 may be an LTE RAN 710 including an evolved node B (eNB), e.g., eNB 712. The LTE RAN 710 may provide an LTE air interface with the following characteristics: SCS at 15 kHz; a CP-OFDM waveform for DL and an SC-FDMA waveform for UL; turbo codes for data, TBCC for control, and the like. The LTE air interface may rely on CSI-RS for CSI acquisition and beam management; relying on a PDSCH/PDCCH demodulation reference signal (DMRS) for PDSCH/PDCCH demodulation; and relying on CRS for cell search and initial acquisition, channel quality measurements, and channel estimation for coherent demodulation/detection at the UE. The LTE air interface may operate over the sub-6 GHz band.

In some embodiments, RAN 704 may be a Next Generation (NG) -RAN 714 having a gNB (e.g., gNB 716) or gn-eNB (e.g., NG-eNB 718). The gNB 716 may connect with 5G-enabled UEs using a 5G NR interface. The gNB 716 may be connected to the 5G core through an NG interface, which may include an N2 interface or an N3 interface. The Ng-eNB 718 may also be connected with the 5G core over the Ng interface, but may be connected with the UE over the LTE air interface. The gNB 716 and ng-eNB 718 may be connected to each other through an Xn interface.

In some embodiments, the NG interface may be divided into two parts, a NG user plane (NG-U) interface, which carries traffic data between nodes of the NG-RAN 714 and the UPF748, and a NG control plane (NG-C) interface, which is a signaling interface (e.g., N2 interface) between the NG-RAN 714 and nodes of the access and mobility management function (AMF) 744.

The NG-RAN 714 may provide a 5G-NR air interface with the following characteristics: variable SCS; CP-OFDM for DL, CP-OFDM for UL, and DFT-s-OFDM; polarity, repetition, simplex, and Reed-Muller (Reed-Muller) codes for control, and LDPC for data. The 5G-NR air interface may rely on CSI-RS, PDSCH/PDCCH DMRS similar to the LTE air interface. The 5G-NR air interface may not use CRS, but may use PBCH DMRS for PBCH demodulation; performing phase tracking of the PDSCH using the PTRS; and time tracking using the tracking reference signal. The 5G-NR air interface may operate over the FR1 band, which includes the sub-6 GHz band, or the FR2 band, which includes the 24.25GHz to 52.6GHz band. The 5G-NR air interface may include SSBs, which are regions of a downlink resource grid including PSS/SSS/PBCH.

In some embodiments, the 5G-NR air interface may use BWP for various purposes. For example, BWP may be used for dynamic adaptation of SCS. For example, UE 702 may be configured with multiple BWPs, where each BWP configuration has a different SCS. When the BWP change is indicated to the UE 702, the SCS of the transmission also changes. Another use case for BWP is related to power saving. In particular, the UE 702 may be configured with multiple BWPs with different numbers of frequency resources (e.g., PRBs) to support data transmission in different traffic load scenarios. BWPs containing a smaller number of PRBs may be used for data transmission with smaller traffic load while allowing power savings at UE 702 and, in some cases, at gNB 716. BWPs containing a large number of PRBs may be used in scenarios with higher traffic loads.

The RAN 704 is communicatively coupled to a CN 720, which includes network elements, to provide various functions to support data and telecommunications services to customers/subscribers (e.g., users of the UE 702). The components of CN 720 may be implemented in one physical node or in different physical nodes. In some embodiments, NFV may be used to virtualize any or all of the functions provided by the network elements of CN 720 onto physical computing/storage resources in servers, switches, and the like. Logical instances of CN 720 may be referred to as network slices, and logical instantiations of a portion of CN 720 may be referred to as network subslices.

In some embodiments, CN 720 may be LTE CN 722, which may also be referred to as Evolved Packet Core (EPC). LTE CN 722 may include Mobility Management Entity (MME) 724, serving Gateway (SGW) 726, serving GPRS Support Node (SGSN) 728, home Subscriber Server (HSS) 730, proxy Gateway (PGW) 732, and policy control and charging rules function (PCRF) 734, which are coupled to each other by an interface (or "reference point") as shown. The functions of the elements of LTE CN 722 may be briefly introduced as follows.

The MME 724 may implement mobility management functions to track the current location of the UE 702 to facilitate patrol, bearer activation/deactivation, handover, gateway selection, authentication, etc.

The SGW 726 may terminate the S1 interface towards the RAN and route data packets between the RAN and the LTE CN 722. SGW 726 may be a local mobility anchor for inter-RAN node handovers and may also provide an anchor for inter-3 GPP mobility. Other responsibilities may include lawful interception, charging, and some policy enforcement.

SGSN 728 may track the location of UE 702 and perform security functions and access control. In addition, SGSN 728 may perform EPC inter-node signaling for mobility between different RAT networks; PDN and S-GW selection specified by MME 724; MME selection for handover, etc. An S3 reference point between MME 724 and SGSN 728 may enable user and bearer information exchange for inter-3 GPP access network mobility in idle/active state.

HSS 730 may include a database for network users that includes subscription-related information that supports network entities handling communication sessions. HSS 730 may provide support for routing/roaming, authentication, admission, naming/addressing resolution, location dependency, etc. The S6a reference point between the HSS 730 and the MME 724 may enable the transmission of subscription and authentication data to authenticate/grant a user access to the LTE CN 720.

PGW 732 may terminate the SGi interface towards a Data Network (DN) 736 that may include an application/content server 738. The PGW 732 may route data packets between the LTE CN 722 and the data network 736. The PGW 732 may be coupled with the SGW 726 by an S5 reference point to facilitate user plane tunneling and tunnel management. PGW 732 may also include nodes (e.g., PCEFs) for policy enforcement and charging data collection. Additionally, the SGi reference point between PGW 732 and data network 736 may be, for example, an operator external public, private PDN, or an operator internal packet data network for providing IMS services. The PGW 732 may be coupled with the PCRF 734 via a Gx reference point.

The PCRF 734 is the policy and charging control element of the LTE CN 722. The PCRF 734 may be communicatively coupled to the application/content server 738 to determine the appropriate QoS and charging parameters for the service flow. The PCRF 732 may provide the associated rules to the PCEF (via the Gx reference point) with the appropriate TFT and QCI.

In some embodiments, CN 720 may be a 5G core network (5 GC) 740. The 5GC 740 may include an authentication server function (AUSF) 742, an access and mobility management function (AMF) 744, a Session Management Function (SMF) 746, a User Plane Function (UPF) 748, a Network Slice Selection Function (NSSF) 750, a network open function (NEF) 752, an NF storage function (NRF) 754, a Policy Control Function (PCF) 756, a Unified Data Management (UDM) 758, and an Application Function (AF) 760, which are coupled to each other by an interface (or "reference point") as shown. The function of the elements of 5GC 740 can be briefly described as follows.

The AUSF 742 may store data for authentication of the UE 702 and handle authentication related functions. The AUSF 742 may facilitate a common authentication framework for various access types. The AUSF 742 may exhibit a Nausf service based interface in addition to communicating with other elements of the 5GC 740 through reference points as shown.

The AMF 744 may allow other functions of the 5GC 740 to communicate with the UE 702 and the RAN 704 and subscribe to notifications about mobility events for the UE 702. The AMF 744 may be responsible for registration management (e.g., registering the UE 702), connection management, reachability management, mobility management, lawful interception of AMF related events, and access authentication and permissions. AMF 744 may provide for the transmission of Session Management (SM) messages between UE 702 and SMF 746, and act as a transparent proxy for routing SM messages. The AMF 744 may also provide for the transmission of SMS messages between the UE 702 and the SMSF. The AMF 744 may interact with the AUSF 742 and the UE 702 to perform various security anchoring and context management functions. Further, AMF 744 may be a termination point for the RAN CP interface, which may include or be an N2 reference point between RAN 704 and AMF 744; the AMF 744 may act as a termination point for NAS (N1) signaling and performs NAS ciphering and integrity protection. The AMF 744 may also support NAS signaling with the UE 702 over the N3IWF interface.

SMF 746 may be responsible for SM (e.g., session establishment, tunnel management between UPF748 and AN 708); UE IP address assignment and management (including optional permissions); selection and control of the UP function; configuring flow control at UPF748 to route the flow to the appropriate destination; termination of the interface to the policy control function; controlling a portion of policy enforcement, charging, and QoS; lawful interception (for SM events and interface to the LI system); terminate the SM portion of the NAS message; a downlink data notification; initiating AN-specific SM message (sent to AN 708 on N2 through AMF 744); and determining an SSC pattern for the session. SM may refer to management of PDU sessions, and a PDU session or "session" may refer to a PDU connectivity service that provides or enables exchange of PDUs between the UE 702 and the data network 736.

The UPF748 may serve as an anchor point for intra-RAT and inter-RAT mobility, an external PDU session point to interconnect with the data network 736, and a branch point to support multi-homed PDU sessions. The UPF748 may also perform packet routing and forwarding, perform packet inspection, perform the user plane part of policy rules, lawful intercepted packets (UP collection), perform traffic usage reporting, perform QoS processing for the user plane (e.g., packet filtering, gating, UL/DL rate enforcement), perform uplink traffic verification (e.g., SDF to QoS flow mapping), transport level packet marking in uplink and downlink, and perform downlink packet buffering and downlink data notification triggering. UPF748 may include an uplink classifier to support routing of traffic flows to a data network.

NSSF 750 may select a set of network slice instances that serve UE 702. NSSF 750 may also determine allowed Network Slice Selection Assistance Information (NSSAI) and mapping to a single NSSAI (S-NSSAI) of the subscription, if desired. NSSF 750 may also determine a set of AMFs to be used to serve UE 702, or determine a list of candidate AMFs, based on a suitable configuration and possibly by querying NRF 754. Selection of a set of network slice instances for UE 702 may be triggered by AMF 744 (with which UE 702 registers by interacting with NSSF 750), which may result in a change in AMF. NSSF 750 may interact with AMF 744 via the N22 reference point; and may communicate with another NSSF in the visited network via an N31 reference point (not shown). Further, NSSF 750 may expose an interface based on NSSF services.

NEF 752 may securely expose services and capabilities provided by 3GPP network functionality for third parties, internal disclosure/re-disclosure, AF (e.g., AF 760), edge computing or fog computing systems, etc. In these embodiments, NEF 752 may authenticate, license, or throttle AFs. NEF 752 may also translate information exchanged with AF 760 and information exchanged with internal network functions. For example, NEF 752 may translate between AF service identifiers and internal 5GC information. NEF 752 may also receive information from other NFs based on their public capabilities. This information may be stored as structured data at NEF 752 or at data store NF using a standardized interface. NEF 752 may then re-disclose the stored information to other NFs and AFs, or for other purposes such as analysis. In addition, NEF 752 may expose an interface based on the Nnef service.

NRF 754 may support a service discovery function, receive NF discovery requests from NF instances, and provide information of discovered NF instances to NF instances. NRF 754 also maintains information of available NF instances and their supported services. As used herein, the terms "instantiate," "instance," and the like may refer to creating an instance, "instance" may refer to a specific occurrence of an object, which may occur, for example, during execution of program code. Further, NRF 754 may expose an interface based on the Nnrf service.

PCF 756 may provide policy rules to control plane functions to enforce them and may also support a unified policy framework to manage network behavior. The PCF 756 may also implement a front end to access subscription information related to policy decisions in the UDR of the UDM 758. In addition to communicating with functions through reference points as shown, PCF 756 also presents an interface based on Npcf services.

The UDM 758 may process subscription-related information to support network entities handling communication sessions and may store subscription data for the UE 702. For example, subscription data may be transferred via an N8 reference point between the UDM 758 and the AMF 744. The UDM 758 may include two parts: front end and UDR are applied. The UDR may store policy data and subscription data for UDM 758 and PCF 756, and/or structured data and application data for disclosure (including PFD for application detection, application request information for multiple UEs 702) for NEF 752. The UDR may expose an interface based on the nurr service to allow the UDM 758, PCF 756, and NEF 752 to access specific sets of stored data, as well as to read, update (e.g., add, modify), delete, and subscribe to notifications of relevant data changes in the UDR. The UDM may include a UDM-FE that is responsible for handling credentials, location management, subscription management, and the like. Several different front ends may serve the same user in different transactions. The UDM-FE accesses subscription information stored in the UDR and performs authentication credential processing, user identification processing, access permission, registration/mobility management, and subscription management. The UDM 758 may also expose a numm service based interface in addition to communicating with other NFs through reference points as shown.

The AF 760 can provide application impact on traffic routing, provide access to NEF, and interact with the policy framework for policy control.

In some embodiments, the 5GC 740 may enable edge computation by selecting an operator/third party service that is geographically close to the point at which the UE 702 attaches to the network. This may reduce latency and load on the network. To provide an edge computing implementation, the 5GC 740 may select the UPF748 close to the UE 702 and perform traffic steering from the UPF748 to the data network 736 over the N6 interface. This may be based on UE subscription data, UE location, and information provided by AF 760. In this way, the AF 760 can affect UPF (re) selection and traffic routing. Based on the operator deployment, the network operator may allow AF 760 to interact directly with the relevant NFs when AF 760 is considered a trusted entity. Additionally, the AF 760 may expose a Naf service based interface.

The data network 736 may represent various network operator services, internet access, or third party services that may be provided by one or more servers, including, for example, an application/content server 738.

Fig. 8 schematically illustrates a wireless network 800 in accordance with various embodiments. The wireless network 800 may include a UE 802 in wireless communication with AN 804. The UE 802 and the AN 804 may be similar to and substantially interchangeable with the co-located components described elsewhere herein.

The UE 802 may be communicatively coupled with AN 804 via a connection 806. Connection 806 is shown as an air interface to enable communicative coupling and may be consistent with a cellular communication protocol operating at millimeter wave (mmWave) or sub-6 GHz frequencies, such as the LTE protocol or the 5G NR protocol.

UE 802 may include a host platform 808 coupled with a modem platform 810. Host platform 808 may include application processing circuitry 812, which may be coupled with protocol processing circuitry 814 of modem platform 810. The application processing circuitry 812 may run various applications of source/receiver application data for the UE 802. The application processing circuitry 812 may also implement one or more layer operations to send/receive application data to/from a data network. These layer operations may include transport (e.g., UDP) and internet (e.g., IP) operations.

The protocol processing circuitry 814 may implement one or more layers of operations to facilitate the transmission or reception of data over the connection 806. Layer operations implemented by the protocol processing circuit 814 may include, for example, MAC, RLC, PDCP, RRC, and NAS operations.

The modem platform 810 may further include digital baseband circuitry 816, the digital baseband circuitry 816 may implement one or more layer operations that are "below" layer operations performed by the protocol processing circuitry 814 in the network protocol stack. These operations may include, for example, PHY operations including one or more of HARQ-ACK functions, scrambling/descrambling, encoding/decoding, layer mapping/demapping, modulation symbol mapping, received symbol/bit metric determination, multi-antenna port precoding/decoding, wherein these functions may include one or more of: space-time, space-frequency, or spatial coding, reference signal generation/detection, preamble sequence generation and/or decoding, synchronization sequence generation/detection, blind control channel signal decoding, and other related functions.

Modem platform 810 may further include transmit circuitry 818, receive circuitry 820, RF circuitry 822, and RF front end (RFFE) circuitry 824, which may include or be connected to one or more antenna panels 826. Briefly, the transmit circuit 818 may include digital-to-analog converters, mixers, intermediate Frequency (IF) components, and the like; the receive circuitry 820 may include analog-to-digital converters, mixers, IF components, etc.; RF circuitry 822 may include low noise amplifiers, power tracking components, and the like; RFFE circuitry 824 may include filters (e.g., surface/bulk acoustic wave filters), switches, antenna tuners, beam forming components (e.g., phased array antenna components), and so forth. The selection and arrangement of components of transmit circuitry 818, receive circuitry 820, RF circuitry 822, RFFE circuitry 824, and antenna panel 826 (collectively, "transmit/receive components") may be specific to details of a particular implementation, e.g., whether the communication is TDM or FDM, at mmWave or sub-6 GHz frequencies, etc. In some embodiments, the transmit/receive components may be arranged in multiple parallel transmit/receive chains, and may be arranged in the same or different chips/modules, etc.

In some embodiments, the protocol processing circuitry 814 may include one or more instances of control circuitry (not shown) to provide control functionality for the transmit/receive components.

UE reception may be established by and via antenna panel 826, RFFE circuitry 824, RF circuitry 822, receive circuitry 820, digital baseband circuitry 816, and protocol processing circuitry 814. In some embodiments, antenna panel 826 may receive transmissions from AN 804 by receiving beamformed signals received by multiple antennas/antenna elements of one or more antenna panels 826.

UE transmissions may be established via and through protocol processing circuitry 814, digital baseband circuitry 816, transmit circuitry 818, RF circuitry 822, RFFE circuitry 824, and antenna panel 826. In some embodiments, transmit components of UE 802 may apply spatial filters to data to be transmitted to form transmit beams transmitted by antenna elements of antenna panel 826.

Similar to the UE 802, the AN 804 may include a host platform 828 coupled with a modem platform 830. Host platform 828 may include application processing circuitry 832 coupled with protocol processing circuitry 834 of modem platform 830. The modem platform may also include digital baseband circuitry 836, transmit circuitry 838, receive circuitry 840, RF circuitry 842, RFFE circuitry 844, and an antenna panel 846. The components of the AN 804 can be similar to, and substantially interchangeable with, the synonymous components of the UE 802. In addition to performing data transmission/reception as described above, the components of AN 804 may also perform various logical functions including, for example, RNC functions such as radio bearer management, uplink and downlink dynamic radio resource management, and data packet scheduling.

Fig. 9 is a block diagram illustrating components capable of reading instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and performing any one or more of the methodologies discussed herein, according to some example embodiments. In particular, fig. 9 shows a diagrammatic representation of hardware resources 900, hardware resources 900 including one or more processors (or processor cores) 910, one or more memory/storage devices 920, and one or more communication resources 930, which may be communicatively coupled via a bus 940. Hardware resource 900 may be part of any entity or non-entity (e.g., service or function) described in this disclosure. For embodiments using node virtualization (e.g., NFV), hypervisor 902 may be executed to provide an execution environment using hardware resources 900 for one or more network slices/subslices.

Processor 910 may include, for example, processor 912 and processor 914. The processor may be, for example, a Central Processing Unit (CPU), a Reduced Instruction Set Computing (RISC) processor, a Complex Instruction Set Computing (CISC) processor, a Graphics Processing Unit (GPU), a Digital Signal Processor (DSP) such as a baseband processor, an Application Specific Integrated Circuit (ASIC), a Radio Frequency Integrated Circuit (RFIC), another processor, or any suitable combination thereof.

Memory/storage 920 may include a main memory, a disk storage, or any suitable combination thereof. The memory/storage 920 may include, but is not limited to, any type of volatile or non-volatile memory, such as Dynamic Random Access Memory (DRAM), static Random Access Memory (SRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid state storage, and the like.

The communication resources 930 may include interconnection or network interface components or other suitable devices to communicate with one or more peripheral devices 904 or one or more databases 906 via the network 908. For example, the communication resources 930 may include wired communication components (e.g., for coupling via a Universal Serial Bus (USB)), cellular communication components, NFC components, bluetooth components (e.g., bluetooth low energy), wi-Fi components, and other communication components.

The instructions 950 may include software, a program, an application, an applet, an app, or other executable code for causing at least any of the processors 910 to perform any one or more of the methods discussed herein. The instructions 950 may reside, completely or partially, within at least one of the processor 910 (e.g., within a processor's cache memory), the memory/storage 920, or any suitable combination thereof. Further, any portion of instructions 950 may be communicated to hardware resource 900 from any combination of peripherals 904 or database 906. Thus, the processor 910, memory/storage 920, peripherals 904, and memory of database 906 are examples of computer-readable and machine-readable media.

The following paragraphs describe examples of various embodiments.

Example 1 includes an apparatus comprising: an interface; and a processor coupled with the interface and configured to: detecting L1 parameter values of a plurality of non-serving cell TRPs for a UE; determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value; and handing over the UE to one of the at least one candidate serving cell TRP.

Example 2 includes the apparatus of example 1, wherein the processor is configured to: determining a non-serving cell TRP having an L1 parameter value higher than a first predetermined threshold value among the plurality of non-serving cell TRPs as a candidate serving cell TRP.

Example 3 includes the apparatus of example 1, wherein the processor is configured to: determining a non-serving cell TRP having the following L1 parameter value among the plurality of non-serving cell TRPs as a candidate serving cell TRP: the L1 parameter value is higher than a current L1 parameter value of a current serving cell TRP of the UE by more than a second predetermined threshold.

Example 4 includes the apparatus of example 1, wherein the processor is configured to: determining a non-serving cell TRP having the following L1 parameter value among the plurality of non-serving cell TRPs as a candidate serving cell TRP: the L1 parameter value is higher than both the current L1 parameter value of the current serving cell TRP of the UE and the other L1 parameter values of the other serving cells TRP of the UE.

Example 5 includes the apparatus of example 1, wherein the at least one candidate serving cell TRP includes all non-serving cell TRPs of the plurality of non-serving cell TRPs or all non-serving cell TRPs of the plurality of non-serving cell TRPs are determined to be candidate serving cell TRPs.

Example 6 includes the apparatus of example 1, wherein the processor is configured to: generating a Scheduling Request (SR); transmitting the scheduling request to a current serving cell TRP of the UE through a PUCCH periodically scheduled by the current serving cell TRP via the interface; receiving an L1 parameter report request from the current serving cell TRP in response to the scheduling request; generating an L1 parameter report in response to the L1 parameter report request, wherein the L1 parameter report includes L1 parameter values of the plurality of non-serving cell TRPs or L1 parameter values of the at least one candidate serving cell TRP; and sending the L1 parameter report to the current serving cell TRP via the interface.

Example 7 includes the apparatus of example 6, wherein the processor is configured to: switching the UE to one of the at least one candidate serving cell TRP indicated by the base station receiving the L1 parameter report from the current serving cell TRP.

Example 8 includes the apparatus of example 6, wherein the L1 parameter report is sent to the current serving cell TRP on UCI in a CSI reporting instance.

Example 9 includes the apparatus of example 6, wherein the L1 parameter report is transmitted to the current serving cell TRP over a PUSCH scheduled by the current serving cell TRP using MAC-CE.

Example 10 includes the apparatus of example 6, wherein the scheduling request has a higher priority than a scheduling request for UL scheduling from a higher layer and a lower priority than a Link Restoration Request (LRR).

Example 11 includes the apparatus of example 7, wherein the one of the at least one candidate serving cell TRP is the candidate serving cell TRP having the best detected L1 parameter value, wherein the L1 parameter value corresponds to the TCI status associated with the candidate serving cell TRP.

Example 12 includes the apparatus of example 11, wherein the TCI state associated with the candidate serving cell TRP is one of a DL TCI state, an UL TCI state, and a joint DL/UL TCI state.

Example 13 includes the apparatus of example 6, wherein the L1 parameter reporting request is transmitted by the current serving cell TRP in a semi-static or aperiodic manner.

Example 14 includes the apparatus of example 1, wherein the processor is configured to periodically detect the L1 parameter value of each of the plurality of non-serving cell TRPs.

Example 15 includes the apparatus of example 1, wherein the L1 parameter value comprises a L1RSRP measurement value for a configured TCI state corresponding to each of the plurality of non-serving cell TRPs.

Example 16 includes the apparatus of example 15, wherein the L1 parameter value is a single short L1RSRP measurement value or a filtered L1RSRP measurement value.

Example 17 includes the apparatus of example 16, wherein the filtered L1RSRP measurement value is a temporally filtered version of the L1RSRP measurement value or a spatially filtered version of the L1RSRP measurement value.

Example 18 includes a method comprising: detecting L1 parameter values of a plurality of non-serving cell TRPs for a UE; determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value; and handing over the UE to one of the at least one candidate serving cell TRP.

Example 19 includes the method of example 18, wherein determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value comprises: determining a non-serving cell TRP having an L1 parameter value higher than a first predetermined threshold value among the plurality of non-serving cell TRPs as a candidate serving cell TRP.

Example 20 includes the method of example 18, wherein determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value comprises: determining a non-serving cell TRP having the following L1 parameter value among the plurality of non-serving cell TRPs as a candidate serving cell TRP: the L1 parameter value is higher than a current L1 parameter value of a current serving cell TRP of the UE by more than a second predetermined threshold.

Example 21 includes the method of example 18, wherein determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value comprises: determining a non-serving cell TRP having the following L1 parameter value among the plurality of non-serving cell TRPs as a candidate serving cell TRP: the L1 parameter value is higher than both the current L1 parameter value of the current serving cell TRP of the UE and the other L1 parameter values of the other serving cells TRP of the UE.

Example 22 includes the method of example 18, wherein the at least one candidate serving cell TRP includes all non-serving cell TRPs of the plurality of non-serving cell TRPs or all non-serving cell TRPs of the plurality of non-serving cell TRPs are determined to be candidate serving cell TRPs.

Example 23 includes the method of example 18, wherein handing over the UE to one of the at least one candidate serving cell TRP comprises: generating a Scheduling Request (SR); transmitting the scheduling request to a current serving cell TRP of the UE through a PUCCH periodically scheduled by the current serving cell TRP; receiving an L1 parameter report request from the current serving cell TRP in response to the scheduling request; generating an L1 parameter report in response to the L1 parameter report request, wherein the L1 parameter report includes L1 parameter values of the plurality of non-serving cell TRPs or L1 parameter values of the at least one candidate serving cell TRP; and sending the L1 parameter report to the current serving cell TRP.

Example 24 includes the method of example 23, wherein handing over the UE to one of the at least one candidate serving cell TRP further comprises: handing over the UE to one of the at least one candidate serving cell TRP indicated by the base station receiving the L1 parameter report from the current serving cell TRP.

Example 25 includes the method of example 23, wherein the L1 parameter report is sent to the current serving cell TRP on UCI in a CSI reporting instance.

Example 26 includes the method of example 23, wherein the L1 parameter report is transmitted to the current serving cell TRP over a PUSCH scheduled by the current serving cell TRP using MAC-CE.

Example 27 includes the method of example 23, wherein the scheduling request has a higher priority than scheduling requests for UL scheduling from higher layers and a lower priority than a Link Restoration Request (LRR).

Example 28 includes the method of example 24, wherein the one of the at least one candidate serving cell TRP is the candidate serving cell TRP having the best detected L1 parameter value, wherein the L1 parameter value corresponds to a TCI status associated with the candidate serving cell TRP.

Example 29 includes the method of example 28, wherein the TCI state associated with the candidate serving cell TRP is one of a DL TCI state, an UL TCI state, and a joint DL/UL TCI state.

Example 30 includes the method of example 23, wherein the L1 parameter reporting request is transmitted by the current serving cell TRP in a semi-static or aperiodic manner.

Example 31 includes the method of example 18, wherein detecting the L1 parameter value for the plurality of non-serving cell TRPs for the UE comprises: periodically detecting an L1 parameter value of each of the plurality of non-serving cell TRPs.

Example 32 includes the method of example 18, wherein the L1 parameter value comprises a L1RSRP measurement value for a configured TCI state corresponding to each of the plurality of non-serving cell TRPs.

Example 33 includes the method of example 32, wherein the L1 parameter value is a single short L1RSRP measurement value or a filtered L1RSRP measurement value.

Example 34 includes the method of example 33, wherein the filtered L1RSRP measurement value is a temporally filtered version of the L1RSRP measurement value or a spatially filtered version of the L1RSRP measurement value.

Example 35 includes an apparatus comprising: means for detecting L1 parameter values for a plurality of non-serving cell TRPs for a UE; means for determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value; and means for handing over the UE to one of the at least one candidate serving cell TRP.

Example 36 includes the apparatus of example 35, wherein the means for determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value comprises: means for determining a non-serving cell TRP of the plurality of non-serving cell TRPs having an L1 parameter value above a first predetermined threshold as a candidate serving cell TRP.

Example 37 includes the apparatus of example 35, wherein the means for determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value comprises: means for determining a non-serving cell TRP of the plurality of non-serving cell TRPs having the following L1 parameter value as a candidate serving cell TRP: the L1 parameter value is higher than a current L1 parameter value of a current serving cell TRP of the UE by more than a second predetermined threshold.

Example 38 includes the apparatus of example 35, wherein the means for determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value comprises: means for determining a non-serving cell TRP of the plurality of non-serving cell TRPs having the following L1 parameter value as a candidate serving cell TRP: the L1 parameter value is higher than both the current L1 parameter value of the current serving cell TRP of the UE and the other L1 parameter values of the other serving cells TRP of the UE.

Example 39 includes the apparatus of example 35, wherein the at least one candidate serving cell TRP includes all non-serving cell TRPs of the plurality of non-serving cell TRPs or all non-serving cell TRPs of the plurality of non-serving cell TRPs are determined to be candidate serving cell TRPs.

Example 40 includes the apparatus of example 35, wherein the means for handing over the UE to one of the at least one candidate serving cell TRP comprises: means for generating a Scheduling Request (SR); means for transmitting the scheduling request to a current serving cell TRP of the UE through a PUCCH periodically scheduled by the current serving cell TRP; means for receiving an L1 parameter report request from the current serving cell TRP in response to the scheduling request; means for generating an L1 parameter report in response to the L1 parameter report request, wherein the L1 parameter report includes L1 parameter values of the plurality of non-serving cell TRPs or L1 parameter values of the at least one candidate serving cell TRP; and sending the L1 parameter report to the current serving cell TRP.

Example 41 includes the apparatus of example 40, wherein the means for handing over the UE to one of the at least one candidate serving cell TRP further comprises: means for handing over the UE to one of the at least one candidate serving cell TRP indicated by the base station receiving the L1 parameter report from the current serving cell TRP.

Example 42 includes the apparatus of example 40, wherein the L1 parameter report is sent to the current serving cell TRP on UCI in a CSI reporting instance.

Example 43 includes the apparatus of example 40, wherein the L1 parameter report is transmitted to the current serving cell TRP over a PUSCH scheduled by the current serving cell TRP using MAC-CE.

Example 44 includes the apparatus of example 40, wherein the scheduling request has a higher priority than a scheduling request for UL scheduling from a higher layer and a lower priority than a Link Restoration Request (LRR).

Example 45 includes the apparatus of example 40, wherein the one of the at least one candidate serving cell TRP is the candidate serving cell TRP having the best detected L1 parameter value, wherein the L1 parameter value corresponds to the TCI status associated with the candidate serving cell TRP.

Example 46 includes the apparatus of example 45, wherein the TCI state associated with the candidate serving cell TRP is one of a DL TCI state, an UL TCI state, and a joint DL/UL TCI state.

Example 47 includes the apparatus of example 40, wherein the L1 parameter reporting request is transmitted by the current serving cell TRP in a semi-static or aperiodic manner.

Example 48 includes the apparatus of example 35, wherein the means for detecting the L1 parameter values for the plurality of non-serving cell TRPs for the UE comprises: means for periodically detecting an L1 parameter value of each of the plurality of non-serving cell TRPs.

Example 49 includes the apparatus of example 35, wherein the L1 parameter value comprises a L1RSRP measurement value for a configured TCI state corresponding to each of the plurality of non-serving cell TRPs.

Example 50 includes the apparatus of example 49, wherein the L1 parameter value is a single short L1RSRP measurement value or a filtered L1RSRP measurement value.

Example 51 includes the apparatus of example 50, wherein the filtered L1RSRP measurement value is a temporally filtered version of the L1RSRP measurement value or a spatially filtered version of the L1RSRP measurement value.

Any of the above examples may be combined with any other example (or combination of examples) unless explicitly stated otherwise. The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the embodiments to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments.

Although certain embodiments have been illustrated and described herein for purposes of description, various alternative and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that the embodiments described herein be limited only by the claims and the equivalents thereof.

Claims

1. An apparatus, comprising:

an interface; and

a processor coupled with the interface and configured to:

detecting L1 parameter values of a plurality of non-serving cell TRPs for a UE;

determining at least one candidate serving cell TRP of the plurality of non-serving cell TRPs based on the L1 parameter value; and

handing over the UE to one of the at least one candidate serving cell TRP.

2. The apparatus of claim 1, wherein the processor is configured to:

determining a non-serving cell TRP having an L1 parameter value higher than a first predetermined threshold value among the plurality of non-serving cell TRPs as a candidate serving cell TRP.

3. The apparatus of claim 1, wherein the processor is configured to:

determining a non-serving cell TRP having the following L1 parameter value among the plurality of non-serving cell TRPs as a candidate serving cell TRP: the L1 parameter value is higher than a current L1 parameter value of a current serving cell TRP of the UE by more than a second predetermined threshold.

4. The apparatus of claim 1, wherein the processor is configured to:

determining a non-serving cell TRP having the following L1 parameter value among the plurality of non-serving cell TRPs as a candidate serving cell TRP: the L1 parameter value is higher than both the current L1 parameter value of the current serving cell TRP of the UE and the other L1 parameter values of the other serving cells TRP of the UE.

5. The apparatus according to claim 1, wherein the at least one candidate serving cell TRP comprises all non-serving cell TRPs of the plurality of non-serving cell TRPs or all non-serving cell TRPs of the plurality of non-serving cell TRPs are determined to be candidate serving cell TRPs.

6. The apparatus of claim 1, wherein the processor is configured to:

generating a Scheduling Request (SR);

transmitting the scheduling request to a current serving cell TRP of the UE through a PUCCH periodically scheduled by the current serving cell TRP via the interface;

receiving an L1 parameter report request in response to the scheduling request from the current serving cell TRP;

generating an L1 parameter report in response to the L1 parameter report request, wherein the L1 parameter report includes L1 parameter values of the plurality of non-serving cell TRPs or L1 parameter values of the at least one candidate serving cell TRP; and

sending the L1 parameter report to the current serving cell TRP via the interface.

7. The apparatus of claim 6, wherein the processor is configured to:

handing over the UE to one of the at least one candidate serving cell TRP indicated by the base station receiving the L1 parameter report from the current serving cell TRP.

8. The apparatus of claim 6, in which the L1 parameter report is sent to the current serving cell TRP in a CSI report instance on UCI.

9. The apparatus of claim 6, wherein the L1 parameter report is transmitted to the current serving cell TRP over a PUSCH scheduled by the current serving cell TRP using a MAC-CE.

10. The apparatus of claim 6, wherein the scheduling request has a higher priority than scheduling requests for UL scheduling from higher layers and a lower priority than a Link Restoration Request (LRR).

11. The apparatus of claim 7, wherein the one of the at least one candidate serving cell TRP is a candidate serving cell TRP having a best detected L1 parameter value, wherein the L1 parameter value corresponds to a TCI state associated with the candidate serving cell TRP.

12. The apparatus of claim 11, wherein the TCI state associated with a candidate serving cell TRP is one of a DL TCI state, an UL TCI state, and a joint DL/UL TCI state.

13. The apparatus of claim 6, in which the L1 parameter reporting request is transmitted by the current serving cell TRP in a semi-static or aperiodic manner.

14. The apparatus according to claim 1, wherein the processor is configured to periodically detect an L1 parameter value of each of the plurality of non-serving cell TRPs.

15. The apparatus of claim 1, wherein the L1 parameter value comprises a L1RSRP measurement value for a configured TCI state corresponding to each of the plurality of non-serving cell TRPs.

16. The apparatus of claim 15, wherein the L1 parameter value is a single short L1RSRP measurement value or a filtered L1RSRP measurement value.

17. The apparatus of claim 16, wherein the filtered L1RSRP measurement value is a temporally filtered version of a L1RSRP measurement value or a spatially filtered version of a L1RSRP measurement value.

18. A method, comprising:

detecting L1 parameter values of a plurality of non-serving cell TRPs for a UE;

switching the UE to one of the at least one candidate serving cell TRP.