EP4649719A1

EP4649719A1 - Method and apparatus for pdcch monitoring and decoding in lower layer centric mobility procedure in a wireless communication system

Info

Publication number: EP4649719A1
Application number: EP23713278.2A
Authority: EP
Inventors: Jia-Hong Liou; Yushu Zhang
Original assignee: Google LLC
Current assignee: Google LLC
Priority date: 2023-02-17
Filing date: 2023-02-17
Publication date: 2025-11-19
Also published as: WO2024168886A1

Abstract

User equipments, network entities and methods, including computer programs encoded on storage media, are provided for PDCCH monitoring and decoding related to a lower layer centric mobility procedure, LLCMP. A UE 102 receives (1502), from a network entity, a cell switch command, CSC, for scheduling the LLCMP which switches from communicating via a source cell to communicating via a target cell among one or more candidate cells. The UE 102 transmits (1504), to the network entity, an acknowledgement, ACK, after a first time interval from the receiving. The UE 102 performs (1506) the LLCMP after a second time interval from the transmitting. The UE 102 selectively uses (1508) beam-related information received via a control channel (PDCCH) during at least one of the first time interval and the second time interval.

Description

METHOD AND APPARATUS FOR PDCCH MONITORING AND DECODING IN LOWER LAYER CENTRIC MOBILITY PROCEDURE IN A WIRELESS COMMUNICATION SYSTEM

TECHNICAL FIELD

The present disclosure relates generally to wireless communication, and more particularly, to performing a lower layer centric mobility procedure.

BACKGROUND

The Third Generation Partnership Project (3GPP) specifies a radio interface referred to as fifth generation (5G) new radio (NR) (5G NR) . An architecture for a 5G NR wireless communication system includes a 5G core (5GC) network, a 5G radio access network (5G-RAN) , a user equipment (UE) , etc. The 5G NR architecture seeks to provide increased data rates, decreased latency, and/or increased capacity compared to prior generation cellular communication systems.
Wireless communication systems, in general, may be configured to provide various telecommunication services (e.g., telephony, video, data, messaging, broadcasts, etc. ) based on multiple-access technologies, such as orthogonal frequency division multiple access (OFDMA) technologies that support communication with multiple UEs. Improvements in mobile broadband continue the progression of such wireless communication technologies. For example, a lower layer centric mobility procedure, LLCMP may present some timing issues related to receiving and applying signals related to the LLCMP. The signals related to the LLCMP are a beam indication specifying beams usable by the UE to communicate via the target cell and a cell switch command, CSC, specifying the target cell.
BRIEF SUMMARY
The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects. This summary neither identifies key or critical elements of all aspects nor delineates the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.
A lower layer centric mobility procedure, LLCMP, (which, for example, may be a L1/L2 triggered mobility procedure) can reduce latency compared with higher layer mobility procedures by avoiding an exchange of higher layer messages and UE reconfiguration when switching from using a source cell to using a target cell for communications between a UE and a network entity. However, the LLCMP may present some interpretation issues related to one or more information fields in messages received from the network via a control channel (e.g., PDCCH) depending on when such messages (e.g., downlink control information, DCI, messages) are received. First, the UE may have interpretation issues when interpreting one or more DCI fields of a DCI scheduling a CSC. Second, the UE may also have interpretation issues on when to perform PDCCH monitoring. The UE may also have issue on how to interpret the DCI depending on whether the message is received during a first time interval between receiving a cell switch command, CSC, and sending a corresponding acknowledgement, ACK, and a second time interval between the transmission of the ACK (or when the CSC becomes active) and a successful completion of the LLCMP. Third, the UE may not be able to monitor PDCCH in a source cell and in a target cell due to the amount of PDCCH blind decoding and control channel element, CCE, overbooking in a slot or in a span (e.g., a mini-slot, a sub-slot or a set of symbols in a slot) .
Aspects of the present disclosure address the above-noted issues by providing mechanisms for the UE to interpret the DCI field differently during the first and second time intervals and to control the amount of the PDCCH candidates.
According to some aspects, the UE receives, from a network entity, a cell switch command, CSC, for triggering a lower layer centric mobility procedure, LLCMP, which switches from communicating via a source cell to communicating via a target cell among one or more candidate cells. The UE transmits, to the network entity, an acknowledgement, ACK, after a first time interval from the receiving. The UE performs the LLCMP after a second time interval from the transmitting. The UE selectively uses beam-related information received via a control channel during at least one of the first time interval and the second time interval.
According to some aspects, network entity transmits, to a user equipment, UE, a cell switch command, CSC, for scheduling a centric mobility procedure, LLCMP, which switches from communicating via a source cell to communicating via a target cell among one or more candidate cells. The network entity receives, from the UE, an acknowledgement, ACK, after a first time interval that corresponds to a first time duration between the UE receiving the CSC and transmitting the ACK. The network entity transmits, to the UE, a message including beam-related information during the first time interval or a second time interval corresponding to a second time duration between the UE transmitting the ACK and transmitting an indication of completion of the LLCM procedure. The message is formatted depending on whether the transmitting occurs during the first time interval or during the second time interval to facilitate UE’s interpretation of the beam-related information being related to the source cell or to the target cell.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a diagram of a wireless communications system that includes a plurality of user equipments (UEs) and network entities in communication over one or more cells.
FIGs. 2A-2B illustrates diagrams of a time delay difference between the CSC and the beam indication and action times of the CSC and the beam indication.
FIG. 3 illustrates a signaling diagram of an example scenario in which UE and network entity exchanges messages and implement procedures for performing a lower layer centric mobility procedure, according to some embodiments.
FIG. 4 illustrates a signaling diagram of an example scenario in which UE and network entity exchanges messages and implement procedures for performing a lower layer centric mobility procedure, according to some embodiments.
FIG. 5 illustrates a signaling diagram of an example scenario in which UE and network entity exchanges messages and implement procedures for performing a lower layer centric mobility procedure, according to some embodiments.
FIG. 6 is a flow diagram illustrating an example method of a lower layer centric mobility procedure, according to some embodiments.
FIG. 7 is a flow diagram illustrating an example method of a lower layer centric mobility procedure, according to some embodiments.
FIG. 8 is a flow diagram illustrating an example method of a lower layer centric mobility procedure, according to some embodiments.
FIG. 9 is a flow diagram illustrating an example method of a lower layer centric mobility procedure, according to some embodiments.
FIG. 10 is a flow diagram illustrating an example method of a lower layer centric mobility procedure, according to some embodiments.
FIG. 11 is a flow diagram illustrating an example method of a lower layer centric mobility procedure, according to some embodiments.
FIG. 12 is a flow diagram illustrating an example method of a lower layer centric mobility procedure, according to some embodiments.
FIG. 13 is a flow diagram illustrating an example method of a lower layer centric mobility procedure, according to some embodiments.
FIG. 14 is a flow diagram illustrating an example method of a lower layer centric mobility procedure, according to some embodiments.
FIG. 15 is a flowchart of a method of wireless communication at a UE.
FIG. 16 is a flowchart of a method of wireless communication at a network entity.
FIG. 17 is a diagram illustrating a hardware implementation for an example UE apparatus.
FIG. 18 is a diagram illustrating a hardware implementation for one or more example network entities.

DETAILED DESCRIPTION

FIG. 1 illustrates a diagram 100 of a wireless communications system associated with a plurality of cells 190. The wireless communications system includes user equipments (UEs) 102 and base stations/network entities 104. Some base stations may include an aggregated base station architecture and other base stations may include a disaggregated base station architecture. The aggregated base station architecture includes a radio unit (RU) 106, a distributed unit (DU) 108, and a centralized unit (CU) 110 that are configured to utilize a radio protocol stack that is physically or logically integrated within a single radio access network (RAN) node. A disaggregated base station architecture utilizes a protocol stack that is physically or logically distributed among two or more units (e.g., RUs 106, DUs 108, CUs 110) . For example, a CU 110 is implemented within a RAN node, and one or more DUs 108 may be co-located with the CU 110, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs 108 may be implemented to communicate with one or more RUs 106. Each of the RU 106, the DU 108 and the CU 110 can be implemented as virtual units, such as a virtual radio unit (VRU) , a virtual distributed unit (VDU) , or a virtual central unit (VCU) . The base station/network entity 104 (e.g., an aggregated base station or disaggregated units of the base station, such as the RU 106, the DU 108, or the CU 110) , may be referred to as a transmission reception point (TRP) .
Operations of the base station 104 and/or network designs may be based on aggregation characteristics of base station functionality. For example, disaggregated base station architectures are utilized in an integrated access backhaul (IAB) network, an open-radio access network (O-RAN) network, or a virtualized radio access network (vRAN) , which may also be referred to a cloud radio access network (C-RAN) . Disaggregation may include distributing functionality across the two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which can enable flexibility in network designs. The various units of the disaggregated base station architecture, or the disaggregated RAN architecture, can be configured for wired or wireless communication with at least one other unit. For example, the base stations 104a/104e and/or the RUs 106a-106d may communicate with the UEs 102a-102d and 102s via one or more radio frequency (RF) access links based on a Uu interface. In examples, multiple RUs 106 and/or base stations 104 may simultaneously serve the UEs 102, such as by intra-cell and/or inter-cell access links between the UEs 102 and the RUs 106/base stations 104.
The RU 106, the DU 108, and the CU 110 may include (or may be coupled to) one or more interfaces configured to transmit or receive information/signals via a wired or wireless transmission medium. A base station 104 or any of the one or more disaggregated base station units can be configured to communicate with one or more other base stations 104 or one or more other disaggregated base station units via the wired or wireless transmission medium. In examples, a processor, a memory, and/or a controller associated with executable instructions for the interfaces can be configured to provide communication between the base stations 104 and/or the one or more disaggregated base station units via the wired or wireless transmission medium. For example, a wired interface can be configured to transmit or receive the information/signals over a wired transmission medium, such as via the fronthaul link 160 between the RU 106d and the baseband unit (BBU) 112 of the base station 104d associated with the cell 190d. The BBU 112 includes a DU 108 and a CU 110, which may also have a wired interface (e.g., midhaul link) configured between the DU 108 and the CU 110 to transmit or receive the information/signals between the DU 108d and the CU 110d. In further examples, a wireless interface, which may include a receiver, a transmitter, or a transceiver, such as an RF transceiver, configured to transmit and/or receive the information/signals via the wireless transmission medium, such as for information communicated between the RU 106a of the cell 190a and the base station 104e of the cell 190e via cross-cell communication beams 136-138 of the RU 106a and the base station 104e.
The RUs 106 may be configured to implement lower layer functionality. For example, the RU 106 is controlled by the DU 108 and may correspond to a logical node that hosts RF processing functions, or lower layer PHY functionality, such as execution of fast Fourier transform (FFT) , inverse FFT (iFFT) , digital beamforming, physical random access channel (PRACH) extraction and filtering, etc. The functionality of the RU 106 may be based on the functional split, such as a functional split of lower layers.
The RUs 106 may transmit or receive over-the-air (OTA) communication with one or more UEs 102. For example, the RU 106b of the cell 190b communicates with the UE 102b of the cell 190b via a first set of communication beams 132 of the RU 106b and a second set of communication beams 134b of the UE 102b, which may correspond to inter-cell communication beams or, in some examples, cross-cell communication beams. For instance, the UE 102b of the cell 190b may communicate with the RU 106a of the cell 190a via a third set of communication beams 134a of the UE 102b and a fourth set of communication beams 136 of the RU 106a. Both real-time and non-real-time features of control plane and user plane communications of the RUs 106 can be controlled by associated DUs 108.
Any combination of the RU 106, the DU 108, and the CU 110, or reference thereto individually, may correspond to a base station 104. Thus, the base station 104 may include at least one of the RU 106, the DU 108, or the CU 110. The base stations 104 provide the UEs 102 with access to a core network. The base stations 104 might relay communications between the UEs 102 and the core network. The base stations 104 may be associated with macrocells for high-power cellular base stations and/or small cells for low-power cellular base stations. For example, the cell 190e may correspond to a macrocell, whereas the cells 190a-190d may correspond to small cells. Small cells include femtocells, picocells, microcells, etc. A cell structure that includes at least one macrocell and at least one small cell may be referred to as a “heterogeneous network. ”
Transmissions from a UE 102 to a base station 104/RU 106 are referred to as uplink (UL) transmissions, whereas transmissions from the base station 104/RU 106 to the UE 102 are referred to as downlink (DL) transmissions. Uplink transmissions may also be referred to as reverse link transmissions and downlink transmissions may also be referred to as forward link transmissions. For example, the RU 106d utilizes antennas 114 of the base station 104d of cell 190d to transmit a downlink/forward link communication to the UE 102d or receive an uplink/reverse link communication from the UE 102d based on the Uu interface associated with the access link between the UE 102d and the base station 104d/RU 106d.
Communication links between the UEs 102 and the base stations 104/RUs 106 may be based on multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be associated with one or more carriers. The UEs 102 and the base stations 104/RUs 106 may utilize a spectrum bandwidth of Y MHz (e.g., 5, 10, 15, 20, 100, 400, 800, 1600, 2000, etc. MHz) per carrier allocated in a carrier aggregation of up to a total of Yx MHz, where x component carriers (CCs) are used for communication in each of the uplink and downlink directions. The carriers may or may not be adjacent to each other along a frequency spectrum. In examples, uplink and downlink carriers may be allocated in an asymmetric manner, more or fewer carriers may be allocated to either the uplink or the downlink. A primary component carrier and one or more secondary component carriers may be included in the component carriers. The primary component carrier may be associated with a primary cell (PCell) and a secondary component carrier may be associated with as a secondary cell (SCell) .
Some UEs 102, such as the UEs 102a and 102s, may perform device-to-device (D2D) communications over sidelink. For example, a sidelink communication/D2D link utilizes a spectrum for a wireless wide area network (WWAN) associated with uplink and downlink communications. The sidelink communication/D2D link may also use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and/or a physical sidelink control channel (PSCCH) , to communicate information between UEs 102a and 102s. Such sidelink/D2D communication may be performed through various wireless communications systems, such as wireless fidelity (Wi-Fi) systems, Bluetooth systems, Long Term Evolution (LTE) systems, New Radio (NR) systems, etc.
The electromagnetic spectrum is often subdivided into different classes, bands, channels, etc., based on different frequencies/wavelengths associated with the electromagnetic spectrum. Fifth-generation (5G) NR is generally associated with two operating frequency ranges (FRs) referred to as frequency range 1 (FR1) and frequency range 2 (FR2) . FR1 ranges from 410 MHz –7.125 GHz and FR2 ranges from 24.25 GHz –71.0 GHz, which includes FR2-1 (24.25 GHz –52.6 GHz) and FR2-2 (52.6 GHz –71.0 GHz) . Although a portion of FR1 is actually greater than 6 GHz, FR1 is often referred to as the “sub-6 GHz” band. In contrast, FR2 is often referred to as the “millimeter wave” (mmW) band. FR2 is different from, but a near subset of, the “extremely high frequency” (EHF) band, which ranges from 30 GHz –300 GHz and is sometimes also referred to as a “millimeter wave” band. Frequencies between FR1 and FR2 are often referred to as “mid-band” frequencies. The operating band for the mid-band frequencies may be referred to as frequency range 3 (FR3) , which ranges 7.125 GHz –24.25 GHz. Frequency bands within FR3 may include characteristics of FR1 and/or FR2. Hence, features of FR1 and/or FR2 may be extended into the mid-band frequencies. Higher operating frequency bands have been identified to extend 5G NR communications above 52.6 GHz associated with the upper limit of FR2. Three of these higher operating frequency bands include FR2-2, which ranges from 52.6 GHz –71.0 GHz, FR4, which ranges from 71.0 GHz –114.25 GHz, and FR5, which ranges from 114.25 GHz –300 GHz. The upper limit of FR5 corresponds to the upper limit of the EHF band. Thus, unless otherwise specifically stated herein, the term “sub-6 GHz” may refer to frequencies that are less than 6 GHz, within FR1, or may include the mid-band frequencies. Further, unless otherwise specifically stated herein, the term “millimeter wave” , or mmW, refers to frequencies that may include the mid-band frequencies, may be within FR2-1, FR4, FR2-2, and/or FR5, or may be within the EHF band.
The UEs 102 and the base stations 104/RUs 106 may each include a plurality of antennas. The plurality of antennas may correspond to antenna elements, antenna panels, and/or antenna arrays that may facilitate beamforming operations. For example, the RU 106b transmits a downlink beamformed signal based on a first set of communication beams 132 to the UE 102b in one or more transmit directions of the RU 106b. The UE 102b may receive the downlink beamformed signal based on a second set of communication beams 134b from the RU 106b in one or more receive directions of the UE 102b. In a further example, the UE 102b may also transmit an uplink beamformed signal to the RU 106b based on the second set of communication beams 134b in one or more transmit directions of the UE 102b. The RU 106b may receive the uplink beamformed signal from the UE 102b in one or more receive directions of the RU 106b.
The UE 102b may perform beam training to determine the best receive and transmit directions for the beamformed signals. The transmit and receive directions for the UEs 102 and the base stations 104/RUs 106 might or might not be the same. In further examples, beamformed signals may be communicated between a first base station/RU 106a and a second base station 104e. For instance, the base station 104e of the cell 190e may transmit a beamformed signal to the RU 106a based on the communication beams 138 in one or more transmit directions of the base station 104e. The RU 106a may receive the beamformed signal from the base station 104e of the cell 190e based on the RU communication beams 136 in one or more receive directions of the RU 106a. In further examples, the base station 104e transmits a downlink beamformed signal to the UE 102e based on the communication beams 138 in one or more transmit directions of the base station 104e. The UE 102e receives the downlink beamformed signal from the base station 104e based on UE communication beams 130 in one or more receive directions of the UE 102e. The UE 102e may also transmit an uplink beamformed signal to the base station 104e based on the UE communication beams 130 in one or more transmit directions of the UE 102e, such that the base station 104e may receive the uplink beamformed signal from the UE 102e in one or more receive directions of the base station 104e.
The base station 104 may include and/or be referred to as a network entity. That is, “network entity” may refer to the base station 104 or at least one unit of the base station 104, such as the RU 106, the DU 108, and/or the CU 110. The base station 104 may also include and/or be referred to as a next generation evolved Node B (ng-eNB) , a generation NB (gNB) , an evolved NB (eNB) , an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a TRP, a network node, network equipment, or other related terminology. The base station 104 or an entity at the base station 104 can be implemented as an IAB node, a relay node, a sidelink node, an aggregated (monolithic) base station with an RU 106 and a BBU 112 that includes a DU 108 and a CU 110, or as a disaggregated base station including one or more RUs 106, DUs 108, and/or CUs 110. A set of aggregated or disaggregated base stations may be referred to as a next generation-radio access network (NG-RAN) . In some examples, the UE 102a operates in dual connectivity (DC) with the base station 104e and the base station/RU 106a. In such cases, the base station 104e can be a master node and the base station/RU 160a can be a secondary node.
Uplink/downlink signaling may also be communicated via a satellite positioning system (SPS) 114. In an example, the SPS 114 of the cell 190c may be in communication with one or more UEs 102, such as the UE 102c, and one or more base stations 104/RUs 106, such as the RU 106c. The SPS 114 may correspond to one or more of a Global Navigation Satellite System (GNSS) , a global position system (GPS) , a non-terrestrial network (NTN) , or other satellite position/location system. The SPS 114 may be associated with LTE signals, NR signals (e.g., based on round trip time (RTT) and/or multi-RTT) , wireless local area network (WLAN) signals, a terrestrial beacon system (TBS) , sensor-based information, NR enhanced cell ID (NR E-CID) techniques, downlink angle-of-departure (DL-AoD) , downlink time difference of arrival (DL-TDOA) , uplink time difference of arrival (UL-TDOA) , uplink angle-of-arrival (UL-AoA) , and/or other systems, signals, or sensors.
Still referring to FIG. 1, in certain aspects, any of the UEs 102 may include a monitoring and decoding component 140 configured to receive, from a network entity, a cell switch command, CSC, for triggering a lower layer centric mobility procedure, LLCMP, which switches from communicating via a source cell to communicating via a target cell among one or more candidate cells; transmit, to the network entity, an acknowledgement, ACK, after a first time interval from the receiving; performing the LLCMP after a second time interval from the transmitting; and selectively use beam-related information received via a control channel during at least one of the first time interval and the second time interval.
In certain aspects, any of the base stations 104 or a network entity of the base stations 104 may include a mobility scheduler component 150 configured to transmit, to a user equipment (UE) , a cell switch command, CSC, for scheduling a centric mobility procedure, LLCMP, which switches from communicating via a source cell to communicating via a target cell among one or more candidate cells; receive, from the UE, an acknowledgement, ACK, after a first time interval that corresponds to a first time duration between the UE receiving the CSC and transmitting the ACK; and to transmit, to the UE, a message including beam-related information during the first time interval or a second time interval corresponding to a second time duration between a transmission of the ACK and receiving an indication that the UE has completed the LLCM procedure, the message being formatted depending on whether the transmitting occurs during the first time interval or during the second time interval to facilitate UE’s interpretation of the beam-related information being related to the source cell or to the target cell.
Accordingly, FIG. 1 describes a wireless communication system that may be implemented in connection with aspects of one or more other figures described herein, such as aspects illustrated in FIGs. 2-18. Further, although the following description may be focused on 5G NR, the concepts described herein may be applicable to other similar areas, such as 5G-Advanced and future versions, LTE, LTE-advanced (LTE-A) , and other wireless technologies, such as 6G.
FIGs. 2A-2B are timeline diagrams 200 and 220 illustrating a first and a second time duration (2A and 2B providing alternative definitions for the second duration) . Referring to FIG. 2A, in some implementations, the first time duration 202 is defined as a time duration starting after (or upon) the UE 102 receives the first or last symbol of the second DCI carrying the CSC 204, and ending at X slots or millisecond after the UE 102 transmits the first or last symbol of a HARQ-ACK bit indicating ACK 206 for the CSC or after the action time of the CSC, where X may be predefined, e.g., X=0, or reported by the UE 102 via UE capability report, or configured by the network entity 104 via an RRC signaling.
In some implementations, during a first time duration, the UE 102 might perform a PDCCH monitoring in the source cell, based on search space set configuration (s) and control resource set (CORESET) configuration (s) for the source cell. In another example, the UE 102 might also perform a DCI interpretation for DCI (s) received in the first time duration for the source cell based on control resource set (CORESET) configuration (s) , BWP configuration (s) and serving cell configuration (s) for the source cell. In a further example, if the UE 102 receives another DCI scheduling a CSC (which could indicate different information from that in the CSC scheduled by the DCI) , the UE 102 might replace the information indicated in the CSC scheduled by the DCI with the CSC scheduled by the another DCI.
In some implementations, the second time duration 208 can be defined as a time duration starting after (or upon) Y symbols or slots or millisecond after the UE 102 transmits the first symbol or last symbol of the PUSCH or PUCCH with a HARQ-ACK bit indicating ACK 206 for the CSC, where Y may be predefined, e.g., 0, or reported by the UE 102 via UE capability report, or configured by the network entity 104 via a higher layer signaling, e.g., RRC signaling.
Referring to FIG. 2B, in some other implementations, the second time duration 228 can be defined starting after (or upon) Y symbols or slots or millisecond after the action time 230 of the CSC, where Y may be predefined, e.g., 0, or reported by the UE via a UE capability report, or configured by the network entity 104 via higher layer signaling, e.g., RRC signaling.
In some implementations, the second time duration can end when at least one of the following event occurs: the lower layer centric mobility procedure is completed 232, and/or after the action time of the CSC scheduled by the second DCI.
In some implementations, during a second time duration, the UE still performs PDCCH monitoring on a subset of or all the search space (s) and control resource set (s) in the source cell. In some other implementations, during the second time duration, the UE stops PDCCH monitoring on a subset of or all the search space (s) and control resource set (s) in the source cell. In some other implementations, the UE reports a UE capability indicating whether the UE is able to monitor the PDCCH on the search space (s) and control resource set (s) in the source cell during the second time duration. In some other implementations, the network entity 104 configures a third RRC parameter indicating whether the UE shall monitor the PDCCH on the search space (s) and control resource set (s) in the source cell during the second time duration.
Further, FIG. 3 illustrates a signaling diagram 300 of an example scenario in which user equipment (UE) and network entity exchanges messages and implement procedures for a lower layer centric mobility procedure to address these technical concerns.
UE 102 monitors PDCCH and decodes control messages (e.g., RRC, MAC-CE and DCI messages) related to the lower layer centric mobility procedure, according to some embodiments. The network entity 104 may correspond to the base station or an entity at the base station, such as the RU 106, the DU 108, the CU 110, etc.
In the signaling diagram 300, the UE 102 may transmit 310 a UE capability report indicating UE’s capability for supporting lower layer centric mobility procedure. As an alternative to over-the-air UE capability reporting, the network entity 104 may receive information about one or more UE capabilities from a core network entity, such as an AMF. Based on the one or more UE capabilities, the network entity 104 may transmit 320 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations. Then, the network entity 104 transmits 324 a downlink control information (DCI) message scheduling a cell switch command (CSC) . The network entity 104 then transmits 330 the CSC for indicating a target cell from configured candidate cells. In response, the UE 102 may transmit 340 an acknowledgement for the CSC. After the UE 102 receives the CSC or transmits the ACK for CSC, the UE 102 performs the lower layer centric mobility procedure according to the CSC. In some other implementations, the lower layer centric mobility procedure is triggered after the UE 102 receives the CSC or transmits the ACK for CSC. When the lower layer centric mobility procedure is completed 360, the current serving cell of the UE 102 has been changed to the target cell indicated by the CSC.
FIG. 4 describes a signaling diagram of another example scenario in which a user equipment (UE) and a network entity exchange messages and implement procedures for performing PDCCH monitoring and decoding in a lower layer centric mobility procedure.
At the beginning of the example scenario 400, the UE 102 may transmit 410, to the network entity 104, a UE capability report indicating UE’s capability for supporting lower layer centric mobility procedure. Based on the one or more UE capabilities conveyed via the UE capability report, the network entity 104 may transmit 420 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations. Then, the network entity 104 transmits 424 a downlink control information (DCI) message scheduling a cell switch command (CSC) . The network entity 104 transmits 430 the CSC for indicating a target cell from configured candidate cells. The network entity 104 transmits 434 another DCI scheduling the CSC. In response, the UE 102 may transmit 440 an acknowledgement for the CSC. After the UE 102 receives the CSC or transmits the ACK for CSC, the UE 102 performs a lower layer centric mobility procedure. In some other implementations, the lower layer centric mobility procedure is triggered after the UE 102 receives the CSC or transmits the ACK for CSC. In block 460, the lower layer centric mobility procedure is completed. When the lower layer centric mobility procedure is completed, the current serving cell of the UE 102 has been changed to the candidate cell indicated by the CSC.
FIG. 5 describes a signaling diagram of another example scenario in which a user equipment (UE) and a network entity exchange messages and implement procedures for performing PDCCH monitoring and decoding in a lower layer centric mobility procedure.
Referring to FIG. 5, at the beginning of the example scenario 500, the UE 102 may transmit 510, to the network entity 104, a UE capability report for supporting UE capability for supporting lower layer centric mobility procedure. Based on the one or more UE capabilities, the network entity 104 may transmit 520 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations. Then, the network entity 104 transmits 524 a downlink control information (DCI) scheduling a cell switch command (CSC) . The network entity 104 transmits 530 the CSC for indicating a target cell from configured candidate cells. In response, the UE 102 may transmit 540 an acknowledgement for the CSC. The network entity 104 additionally transmits 444 another DCI scheduling the CSC. After the UE 102 receives 544 the other DCI, the UE 102 performs a lower layer centric mobility procedure. In some other implementations, the lower layer centric mobility procedure is triggered after the UE 102 receives the CSC or transmits the ACK for CSC. In block 560, the lower layer centric mobility procedure is completed. When the lower layer centric mobility procedure is completed, the current serving cell of the UE 102 has been changed to the candidate cell indicated by the CSC.
In some implementations, a TRP can be associated with or identified by a TRP identifier. In some implementations, a base station (e.g., the network entity 104 or 106) includes or configures a TRP identifier in uplink (UL) configurations that the network entity 104 transmits to a UE (e.g., the UE 102) for UL transmissions via a TRP identified by the TRP identifier. In some implementation, the UL configurations include downlink control information (DCI) transmitted on a PDCCH, and/or physical uplink shared channel (PUSCH) configuration, physical uplink control channel (PUCCH) configuration and/or sounding reference signal (SRS) configuration included in a RRC message (e.g., RRC reconfiguration message or a RRC resume message) that network entity 104 transmits to the UE 102. In some implementations, the UL transmissions include PUSCH transmissions, PUCCH transmissions and/or SRS transmissions. In some implementations, the network entity 104 includes a TRP identifier in downlink (DL) configurations that the network entity 104 transmits to the UE 102 for DL transmissions via a TRP identified by the TRP identifier. In one implementation, the DL configurations include DCI transmitted on a PDCCH, and/or channel state information (CSI) resource configuration, physical downlink shared channel (PDSCH) configurations and/or physical downlink control channel (PDCCH) configurations included in a RRC message (e.g., RRC reconfiguration message or a RRC resume message) that the network entity 104 transmits to the UE 102. In some implementations, the DL transmissions include CSI reference signal (CSI-RS) transmissions, synchronization signal block (SSB) transmissions, PDSCH transmissions and/or PDCCH transmissions.
In other implementations, the network entity 104 does not transmit or configure a TRP identifier to the UE 102 and the network entity 104 uses an implicit indication to indicate a TRP to the UE 102. In one implementation, the implicit indication can be one of the following configuration parameters: a CORESETPoolIndex, a value (candidate) of a CORESETPoolIndex, dataScramblingIdentityPDSCH, dataScramblingIdentityPDSCH2-r16, or PUCCH-ResourceGroup-r16. In such implementations, the UE 102 derives a TRP (identifier) from the implicit indication. In some implementations, the network entity 104 transmits a RRC message (e.g., RRC reconfiguration message or a RRC resume message) including the configuration parameters to the UE 102.
In some implementations, the network entity 104 configures or indicates the UE a first TRP identifier. In some implementations, the UE 102 derives a first TRP identifier (value) . In some implementations, the network entity 104 configures or indicates the UE 102 a second TRP identifier (value) . In some implementations, the UE 102 derives a second TRP identifier (value) . In some implementations, the first TRP identifier can be associated with the first TRP. In some implementations, the second TRP identifier can be associated with the second TRP.
In some implementations, the network entity 104 configures that a serving cell is associated with the first TRP or the first TRP identifier (value) . In some implementations, the network entity 104 configures a first control resource set (CORESET) associated with the serving cell or first TRP. The network entity 104 can configure CORESETPoolIndex #0 to identify the first CORESET. In one implementation, the network entity 104 can transmit to the UE 102 a RRC message (e.g., a RRC setup message, a RRC reconfiguration message or a RRC resume message) configuring the first CORESET and/or including the CORESETPoolIndex #0.Thus, the UE 102 monitors a PDCCH on the first CORESET to receive DCIs from the network entity 104, which implies that the UE 102 monitors a PDCCH or receives DCIs via the first TRP from the network entity 104 (i.e., from the first TRP) . In such a case, the UE 102 determines that CORESETPoolIndex #0 indicates a TRP (i.e., the first TRP) of the network entity 104.
In one implementation, the network entity 104 configures that the serving cell associated with the second TRP or the second TRP identifier (value) . In other implementation, the second TAG is associated with a non-serving cell, and the network entity 104 indicates or configures the association in the second RRC message. In one implementation, the network entity 104 configures the non-serving cell associated with the second TRP or the second TRP identifier (value) . In some implementations, the network entity 104 configures a second CORESET is associated with the serving cell, non-serving cell or second TRP. The network entity 104 can configure CORESETPoolIndex #1 to identify the second CORESET. In one implementation, the network entity 104 can transmit to the UE 102 a RRC message (e.g., a RRC setup message, a RRC reconfiguration message or a RRC resume message) configuring the second CORESET and/or including the CORESETPoolIndex #1. Thus, the UE 102 monitors a PDCCH on the second CORESET to receive DCIs from the network entity 104, which implies that the UE 102 monitors a PDCCH or receives DCIs via the second TRP from the network entity 104 (i.e., from the second TRP) . In such a case, the UE 102 determines that CORESETPoolIndex #1 indicates a TRP (i.e., the second TRP) .
In some implementations, the network entity 104 can configure the UE 102 one or more TCI state lists for a component carrier (CC) of a serving cell, where the CC might be PCell or SCell. For example, the network entity 104 can configure a joint TCI state list for a CC of a serving cell. For example, the network entity 104 can configure a DL TCI state list and/or a UL TCI state list for a CC of a serving cell. One joint TCI state list can include one or more joint TCI states. One DL TCI state list can include one or more DL TCI states. One UL TCI state list can include one or more UL TCI states.
In some implementations, the network entity 104 can configure the UE a RRC parameter unifiedTCI-StateType. The RRC parameter unifiedTCI-StateType can be a per-serving-cell configuration. The RRC parameter unifiedTCI-StateType can indicate which type of TCI state list (s) for a serving cell. For example, the RRC parameter unifiedTCI-StateType can indicate “joint” or “separate” . The RRC parameter unifiedTCI-StateType can provide one or more the following purpose: if the first RRC parameter for a CC of serving cell indicates “joint” , the network entity 104 might explicitly or implicitly configure the UE one or more joint TCI state list (s) for the CC of serving cell or the UE 102; if the first RRC parameter for a CC of serving cell indicates “separate” , the network entity 104 might explicitly or implicitly configure the UE one or more DL TCI state list (s) for the CC of serving cell; if the first RRC parameter for a CC of serving cell indicates “separate” , the network entity 104 might explicitly or implicitly configure the UE one or more UL TCI state list (s) for the CC of serving cell.
In some implementations, if the network entity 104 explicitly configures the UE 102 one or more TCI state list (s) for a CC of a serving cell, it might imply that the network entity 104 configures the one or more TCI state list (s) (explicitly) under RRC configuration (e.g., ServingCellConfig) for a CC of the serving cell.
In some implementations, if the network entity 104 implicitly configures the UE 102 one or more TCI state list (s) for a CC of serving cell, it might imply at least one of the followings: the network entity 104 configures the one or more TCI state list (s) under RRC configuration (e.g., ServingCellConfig) for other serving cell (s) /CCs or a reference serving cell/CC; the UE 102 refers the one or more TCI state list (s) for other serving cell (s) /CCs or a reference serving cell/CC; the UE 102 determines that the one or more TCI state list (s) , which is for other serving cell/CCs or a reference serving cell/CC, is also for the CC of the serving cell.
In some implementations, the network entity 104 can transmit a first MAC-CE to the UE 102 when or after the network entity 104 configures the UE 102 one or more TCI state list (s) for the CC of serving cell; and/or the UE 102 refers or determines one or more TCI state list (s) for the CC of serving cell.
In some implementations, the first MAC-CE can activate or indicate one or more TCI states from the one or more TCI state list (s) . The one or more TCI states activated/indicated by the first MAC-CE can map to one or more TCI codepoints in a TCI field. In some cases, the UE 102 can (directly) apply or use the one or more TCI states activated/indicated by the first MAC-CE for performing DL and/or UL transmission (subsequently) .
In some implementations, if the number of TCI states activated/indicated by the first MAC-CE is larger than one, those TCI states activated/indicated by the first MAC-CE can map to one or more TCI codepoints in a TCI field in a DCI. In some implementations, if the number of TCI states activated/indicated by the first MAC-CE is one, the UE 102 can (directly) apply or use the TCI state activated/indicated by the first MAC-CE for performing DL and/or UL transmission (subsequently) . In some implementations, if the number of TCI states activated/indicated by the first MAC-CE is two, and/or if the two TCI states activated/indicated by the first MAC-CE are associated with different TRP identifier or applicable for different TRP, the UE 102 can (directly) apply or use these two TCI states activated/indicated by the first MAC-CE for performing corresponding DL and/or UL transmission (subsequently) .
In some implementations, one TCI state can be mapped to one TCI codepoint, based on the first MAC-CE. In some cases, more than one TCI states can be mapped to one TCI codepoint, based on the first MAC-CE. In some cases, the TCI codepoint can indicate one of the followings: one or more joint TCI states, some might be TCI states associated with the first TRP, the other might be TCI states associated with the second TRP one or more DL TCI states, some might be TCI states associated with the first TRP, the other might be TCI states associated with the second TRP one or more UL TCI states, some might be TCI states associated with the first TRP, the other might be TCI states associated with the second TRP one or more DL TCI states and one or more UL TCI states, some might be TCI states associated with the first TRP, the other might be TCI states associated with the second TRP.
In some cases, the number of joint TCI states indicated in a TCI codepoint by the network entity 104 can be up to 4. In some cases, the number of DL TCI states indicated in a TCI codepoint by the network entity 104 can be up to 4. In some cases, the number of UL TCI states indicated in a TCI codepoint by the network entity 104 can be up to 4.
For example, one of the followings can be mapped to a TCI codepoint: one joint TCI state associated with the first TRP, one joint TCI state associated with the second TRP, one DL TCI state associated with the first TRP, one UL TCI state associated with the second TRP, one DL TCI state associated with the first TRP, one DL TCI state associated with the second TRP, one UL TCI state associated with the first TRP, one UL TCI state associated with the second TRP, one DL TCI state and one UL TCI state associated with the first TRP, one joint TCI state associated with the second TRP, one DL TCI state and one UL TCI state associated with the first TRP, one DL TCI state associated with the second TRP, one DL TCI state and one UL TCI state associated with the first TRP, one ULTCI state associated with the second TRP.
In some implementations, the UE 102 can receive a first DCI indicating one or more TCI states. The first DCI can indicate one or more TCI states by the TCI field in the first DCI. In response to receiving the first DCI, the UE can transmit, to the network entity 104, a first acknowledgement signal via a PUCCH or PUSCH transmission. In response to transmitting the first acknowledgement signal, the UE 102 can apply or use the one or more TCI states activated or indicated by the first DCI for performing DL and/or UL transmission. In some cases, in response to transmitting the first acknowledgement signal, the UE 102 can apply or use the one or more TCI states activated/indicated by the first DCI for performing DL and/or UL transmission, after a first application time period. In some cases, the UE 102 can apply or use the one or more TCI states activated/indicated by the first DCI for performing DL and/or UL transmission, starting from a first slot.
In some cases, the first slot can be the earliest slot that is at least the first application time period after the last symbol of the PUCCH or PUSCH transmission. In some cases, the earliest slot (for determining the first slot) and/or the first application time period can be determined based on the active BWP with the smallest SCS among the active BWP (s) of the carrier/serving cell (s) applying the one or more TCI states. In some cases, the first application time period can be in unit of one of the followings: symbol, sub-slot, slot, sub-frame, frame, millisecond, or second. In some cases, the first application time period can be beamAppTime.
In other implementations, the UE 102 can receive the first MAC-CE indicating one or more TCI states. For example, the first MAC-CE might indicate one TCI state. For example, the first MAC-CE might indicate more than one TCI states, each of them can be associated with different TRP or TRP identifier. For example, the first MAC-CE might indicate two TCI states, where one is associated with the first TRP (identifier) and the other is associated with the second TRP (identifier) . In such cases, the UE 102 might not receive a DCI indicating one or more TCI states for applying for subsequent DL and/or UL transmission. In response to receiving the first MAC-CE, the UE 102 can transmit, to the network entity 104, a second acknowledgement signal via a PUCCH or PUSCH transmission. In response to transmitting the second acknowledgement signal, the UE 102 can apply or use the one or more TCI states activated/indicated by the first MAC-CE for performing DL and/or UL transmission. In some cases, in response to transmitting the second acknowledgement signal, the UE 102 can apply or use the one or more TCI states activated/indicated by the first MAC-CE for performing DL and/or UL transmission, after a second application time period. In some cases, the UE 102 can apply or use the one or more TCI states activated/indicated by the first MAC-CE for performing DL and/or UL transmission, starting from a second slot.
In some cases, the second slot can be the earliest slot that is at least the second application time period after the (last) slot of the PUCCH or PUSCH transmission. In some cases, the second application time period can be In some cases, μ can be the SCS configuration for the PUCCH or PUSCH transmission; can be the subcarrier spacing configuration for k_macwith a value of 0 for frequency range 1, and k_macis provided by K-Mac or k_mac=0 if K-Mac is not provided.
In some cases, the network entity 104 can configure the UE 102 a RRC parameter unifiedTCI-StateRef. The RRC parameter unifiedTCI-StateRef can be a per-cell or per-BWP configuration. In some cases, if the network entity 104 configures, to the UE 102, the RRC parameter unifiedTCI-StateRef for a CC of serving cell and/or a BWP, it might imply one of the followings: the network entity 104 does not configure one or more TCI state list (s) under RRC configuration (e.g., ServingCellConfig) for the CC of serving cell and/or RRC configuration for the BWP; the UE 102 refers one or more TCI state list (s) for the serving cell and/or the BWP from a reference serving cell/CC and/or a reference BWP; the UE 102 determines that the one or more TCI state list (s) , which is for the reference serving cell/CC and/or the reference BWP, is also for the CC of serving cell and the BWP. In some cases, the RRC parameter unifiedTCI-StateRef can at least indicate a cell index of the reference serving cell. In some cases, the RRC parameter unifiedTCI-StateRef can at least indicate a BWP ID of the reference BWP.
In some implementations, the network entity 104 might configure the UE 102 one or more candidate cell configuration (s) . The one or more candidate cell configuration (s) might include information of neighboring cell (s) of the UE 102. The one or more candidate cell configuration (s) might include information of candidate target cell of the UE 102 for performing a lower layer centric mobility procedure. A candidate cell configuration might include or be one of a RRCReconfiguration message, a CellGroupConfig IE or a SpCellConfig IE. A candidate cell configuration might include a candidate cell configuration ID. A candidate cell might be current configured/activated secondary cell (SCell) of the UE 102.
In some implementations, the candidate cell configuration may include one or more TCI state lists for a candidate cell. In some implementations, the network entity 104 might transmit to the UE 102 a cell switch command. In one example, the network entity 104 might transmit the cell switch command via MAC-CE or PDSCH. In some implementations, the UE 102 might receive a second DCI from the network entity 104. The second DCI might schedule a PDSCH carrying the CSC.
In some implementations, the CSC might indicate a target cell. In some implementations, the CSC might include a candidate cell configuration ID. It is noted that throughout this disclosure, a target cell might be or stand for a candidate cell indicated by the CSC. In response to receiving the CSC or after the action time of the CSC, the UE 102 might perform lower layer centric mobility procedure based on the CSC. The UE 102 might determine the target cell and/or its corresponding configuration based on the candidate cell configuration ID indicated in the cell switch command. Upon completing the lower layer centric mobility procedure, the target cell indicated by the cell switch command might become a new serving cell or a PCell. Upon completing the lower layer centric mobility procedure, the UE 102 moves from the source cell to the target cell. It is noted that throughout this disclosure, the source cell might be the (original or previous) serving cell before receiving the CSC or completing lower layer centric procedure.
FIG. 5 describes a signaling diagram of an example scenario in which a user equipment (UE) and a network entity exchange messages and implement procedures for performing PDCCH monitoring and decoding in a lower layer centric mobility procedure, and FIG. 6 describes a method of the lower layer centric mobility procedure from a UE-side of the wireless communication link.
Now turning to FIG. 6 which illustrates an example method 600 for the lower layer centric mobility procedure implemented in the UE. The method 600 can be implemented by UE 102 and network entity 104 depicted in FIG. 1. With reference to FIGs. 1 and 17, the method may be performed by the UE 102, the UE apparatus 1700, etc., which may include the memory 1724’ and which may correspond to the entire UE 102 or the UE apparatus 1700, or a component of the UE 102 or the UE apparatus 1700, such as the wireless baseband processor 1724, and/or the application processor 1706.
Referring to FIG. 6, at block 602, the UE 102 transmits to the network entity 104, a UE capability report for supporting UE capability for supporting lower layer centric mobility procedure. For example, referring to FIG. 3, the UE 102 transmits 310 a UE capability report for supporting lower layer centric mobility procedure.
At block 604, the UE 102 receives, from the network entity 104, a RRC configuration configuring candidate cell configuration (s) for a target cell. For example, referring to FIG. 3, the UE 102, based on the one or more UE capabilities, the UE 102 may receive 320 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations.
At block 606, the UE 102 receives, from the network entity, a DCI with a TCI field. For example, referring to FIG. 3, the UE 102 receives 324 a downlink control information (DCI) scheduling a cell switch command (CSC) . The DCI includes a TCI field.
At block 608, the UE 102 determines whether the DCI schedules the CSC indicating the target cell.
If the UE 102 determines the DCI schedules the CSC indicating the target cell, at block 610, the UE 102 ignores information indicated by the TCI field.
If the UE 102 determines the DCI does not schedule the CSC indicating the target cell, at block 612, the UE 102 switches or updates beam if the TCI field indicates a beam different from the currently used beam.
FIG. 6 describes a method of the lower layer centric mobility procedure from a UE-side of the wireless communication link, and FIG. 7 describes a method of the lower layer centric mobility procedure from a UE-side of the wireless communication link.
In some implementations, the UE 102 may interpret one or more DCI field (s) in a DCI differently based on whether the DCI schedules CSC. This implies that for the first DCI and the second DCI, although the first DCI and the second DCI have the same DCI format and transmitted by the network entity 104 in the same BWP or the serving cell, the UE 102 may interpret one or more DCI field (s) in the first DCI and the second DCI differently.
In some implementations, if the UE 102 receives the second DCI scheduling the CSC, the UE 102 performs one of the following behaviors, if a TCI field is present in the second DCI. For example, the UE: ignores or discards information indicated in the TCI field, and/or; determines or considers the TCI field is repurposed or used for purpose other than TCI indication. For such behavior, the UE 102 can interpret the TCI field by combining other field (s) in the second DCI, e.g., BWP field. The UE 102 can also use the TCI field for DCI decoding validation, where the TCI field indicates a predefined value, e.g., all bits as “0” or “1” .
In some implementations, if the network entity 104 transmits the second DCI scheduling the CSC, the network entity 104 may perform one of the following behaviors: the network entity 104 prevents from configuring or is not allowed to configure the second DCI having the TCI field or the network entity 104 configures that a function “TCI field in DCI” is disabled in a CORESET scheduling the second DCI, e.g., the network entity 104 configures the scheduling CORESET without configuring the RRC parameter tci-PresentInDCI and tciPresentInDCI-1-2, if the DCI format of the second DCI is DCI format 1_1 or 1_2, and/or; the network entity 104 only uses or sets DCI format 1_1/1_2 without TCI field configured/present or DCI format 1_0 as the DCI format for the second DCI.
FIG. 6 describes a method from a UE-side of a wireless communication link, whereas FIG. 7 describes another method from a UE-side of the wireless communication link.
Now turning to FIG. 7 which illustrates an example method 700 for supporting lower layer centric mobility procedure implemented in the UE. The method 700 can be implemented by UE 102 and network entity 104 depicted in FIG. 1. With reference to FIGs. 1 and 17, the method may be performed by the UE 102, the UE apparatus 1700, etc., which may include the memory 1724’ and which may correspond to the entire UE 102 or the UE apparatus 1700, or a component of the UE 102 or the UE apparatus 1700, such as the wireless baseband processor 1724, and/or the application processor 1706.
Referring to FIG. 7, the method 700 begins at block 702 where the UE 102 transmits to the network entity 104, a UE capability report for supporting UE capability for supporting lower layer centric mobility procedure. For example, referring to FIG. 3, the UE 102 transmits 310 a UE capability report for supporting lower layer centric mobility procedure.
At block 704, the UE 102 receives, from the network entity 104, a RRC configuration configuring candidate cell configuration (s) for a target cell. For example, referring to FIG. 3, the UE 102, based on the one or more UE capabilities, the UE 102 may receive 320 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations.
At block 706, the UE 102 receives, from the network entity, a RRC configuration configuring only one BWP configuration for the target cell. For example, referring to FIG. 3, the UE 102, based on the one or more UE capabilities, the UE 102 may receive 320 a RRC configuring only one BWP configuration for the target cell.
At block 708, the UE 102 receives, from the network entity 104, a DCI with BWP field. For example, referring to FIG. 3, the UE 102 receives 324 a downlink control information (DCI) scheduling a cell switch command (CSC) . The DCI includes a BWP field.
At block 710, the UE 102 determines whether the DCI schedules a CSC indicating the target cell. For example, referring to FIG. 4, the UE 102 receives 430 the CSSC indicating a target cell.
If the UE 102 determines the DCI schedules a CSC indicating the target cell, at block 712, the UE 102 ignores information indicated by the BWP field.
Then, at block 714, the UE 102 performs a BWP switching in the target cell based on the BWP configuration for the target cell.
If the UE 102 determines the DCI does not schedule a CSC indicating the target cell, at block 716, the UE 102 performs BWP switching in the source cell if the BWP field indicates a BWP that is different from current active BWP.
In some implementations, if the UE 102 receives the second DCI scheduling the CSC, the UE 102 could perform one of the following behaviors, if a BWP field is present in the second DCI: ignores or discards information indicated in the BWP field, and/or determines or considers the BWP field is for purpose other than indication of BWP switching or active BWP change, and/or uses the BWP field for DCI decoding validation, where the BWP field shall indicate a pre-defined value, e.g., all bits as “0” or “1” .
In some implementations, if the UE 102 receives the second DCI scheduling the CSC, and regardless of whether a BWP field is present in the second DCI, the UE could determine active BWP in the target cell (i.e., the candidate cell indicated by the CSC) : a BWP ID or BWP information/configuration configured in configuration corresponding to the target cell (i.e., the candidate cell indicated by the CSC) , and/or frequency range as the SSBs for measurements for the target cell (i.e., the candidate cell indicated by the CSC) , and/or initial BWP indicated by the SSBs for measurements for the target cell (i.e., the candidate cell indicated by the CSC) .
In some implementations, the candidate cell configuration indicated by the CSC only includes or comprises one BWP configuration. In some cases, when the network entity 104 transmits the CSC, the network entity 104 makes sure that the candidate cell configuration indicated by the CSC only includes or comprises one BWP configuration. In some cases, the network entity 104 only configures one BWP in each candidate cell configuration (s) configured to the UE.
FIG. 7 describes a method from a UE-side of a wireless communication link, whereas FIG. 8 describes another method from a UE-side of the wireless communication link.
Now turning to FIG. 8 which illustrates an example method 800 for supporting lower layer centric mobility procedure implemented in the UE. The method 800 can be implemented by UE 102 and network entity 104 depicted in FIG. 1. With reference to FIGs. 1 and 17, the method may be performed by the UE 102, the UE apparatus 1700, etc., which may include the memory 1724’ and which may correspond to the entire UE 102 or the UE apparatus 1700, or a component of the UE 102 or the UE apparatus 1700, such as the wireless baseband processor 1724, and/or the application processor 1706.
Referring to FIG. 8, the method 800 begins at block 802 where the UE 102 transmits to the network entity 104, a UE capability report for supporting UE capability for supporting lower layer centric mobility procedure. For example, referring to FIG. 3, the UE 102 transmits 310 a UE capability report for supporting lower layer centric mobility procedure.
At block 804, the UE 102 receives, from the network entity 104, a RRC configuration configuring candidate cell configuration (s) for a target cell. For example, referring to FIG. 3, the UE 102, based on the one or more UE capabilities, the UE 102 may receive 320 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations.
At block 807, the UE 102 receives, from the network entity 104, a RRC configuration configuring one or more BWP configurations for the target cell. For example, referring to FIG. 3, the UE 102, based on the one or more UE capabilities, the UE 102 may receive 320 a RRC configuring one or more BWP configurations for the target cell.
At block 808, the UE 102 receives, from the network entity 104, a DCI with BWP field. For example, referring to FIG. 3, the UE 102 receives 324 a downlink control information (DCI) scheduling a cell switch command (CSC) . The DCI includes a BWP field.
At block 810, the UE 102 determines whether the DCI schedules a CSC indicating the target cell. If the UE 102 determines the DCI schedules a CSC indicating the target cell, at block 813, the UE 102 performs BWP switching in the target cell based on the BWP field. If the UE 102 determines the DCI does not schedule a CSC indicating the target cell, at block 816, the UE 102 performs BWP switching in the source cell if the BWP field indicates a BWP that is different from current active BWP.
In some implementations, if the UE 102 receives or detects a DCI with a BWP field present/configured, the UE 102 could determine whether the indicated BWP change is for the serving cell or candidate cell (s) based on one of the followings:
If the DCI schedules the CSC (e.g., the second DCI) , the indicated BWP change is for the target cell indicated by the CSC; otherwise (e.g., the first DCI) , the indicated BWP change is for the serving cell.
In such cases, the BWP switch delay in the serving cell without supporting lower layer centric mobility (say a first BWP switch delay) could be different from that with supporting lower layer centric mobility (say a second BWP switch delay) . Optionally, the second BWP switch delay could be longer than the first BWP switch delay.
In such cases, alternatively, the second BWP switch delay could be the same as the first BWP switch delay. In this case, the timing/slot to start or apply the second BWP switch delay could be different from that of the fist BWP switch delay.
For example, the timing/slot to start or apply the second BWP switch delay could be after decoding PDSCH or CSC scheduled by the DCI (e.g., the second DCI) . The timing/slot to start or apply the second BWP switch delay could be at the first or last symbol of PDSCH or CSC scheduled by the DCI (e.g., the second DCI) . The timing/slot to start or apply the second BWP switch delay could be a time interval after the end of PDSCH or CSC scheduled by the DCI (e.g., the second DCI) . In some cases, the time interval could be in unit of symbols, slots or milliseconds (ms) . In some cases, the network entity 104 could indicate/configure the time interval to the UE via RRC, MAC-CE or DCI. The timing/slot to start or apply the second BWP switch delay could be after transmitting the first or last symbol of ACK for PDSCH or CSC scheduled by the DCI (e.g., the second DCI) . The timing/slot to start or apply the second BWP switch delay could be (the beginning of) the slot where the PDSCH carrying the CSC is received. The timing/slot to start or apply the second BWP switch delay could be (the beginning of) the earliest available slot after the slot where the PDSCH carrying the CSC is received. The timing/slot to start or apply the second BWP switch delay could be (the beginning of) the slot where the ACK for PDSCH or CSC is transmitted by the UE. The timing/slot to start or apply the second BWP switch delay could be (the beginning of) the earliest available slot after the slot where the ACK for PDSCH or CSC is transmitted by the UE.
For example, the timing/slot to start or apply the first BWP switch delay could be after decoding the DCI (e.g., the second DCI) . The timing/slot to start or apply the first BWP switch delay could be the beginning of the slot where the DCI is received (e.g., the second DCI) .
In some implementations, if the UE 102 receives or detects a DCI with a BWP field present/configured, the UE 102 could determine whether the indicated BWP change is for the serving cell or candidate cell (s) based on one field or bit (s) in the DCI, which could indicate whether the indicated BWP change is intended for the serving cell or candidate cell (s) .
In some implementations, if the UE 102 receives or detects a DCI with a BWP field present/configured, and if the UE 102 determines whether the indicated BWP change is for the serving cell or candidate cell (s) based on whether the DCI schedules the CSC (e.g., the second DCI) , the PDSCH scheduled by the DCI could be transmitted by the network entity 104 in the current active BWP (i.e., the active BWP before the UE 102 receives the DCI) in the serving cell or the source cell.
In some implementations, if the network entity 104 configures or indicates LTM function (or the UE supports LTM function) , if the UE 102 receives or detects a DCI with a BWP field present/configured, the UE 102 receives a PDSCH scheduled by the DCI (if any) in the current active BWP (i.e., the active BWP before the UE 102 receives the DCI) in the serving cell or the source cell; if the network entity 104 does not configure or indicate LTM function (or the UE 102 does not support LTM function) , if the UE 102 receives or detects a DCI with a BWP field present/configured, the UE 102 receives a PDSCH scheduled by the DCI (if any) in the BWP (indicated by the BWP field) in the serving cell or the source cell.
FIG. 8 describes a method from a UE-side of a wireless communication link, whereas FIG. 9 describes another method from a UE-side of the wireless communication link.
Now turning to FIG. 9 which illustrates an example method 900 for supporting lower layer centric mobility procedure implemented in the UE. The method 900 can be implemented by UE 102 and network entity 104 depicted in FIG. 1. With reference to FIGs. 1 and 17, the method may be performed by the UE 102, the UE apparatus 1700, etc., which may include the memory 1724’ and which may correspond to the entire UE 102 or the UE apparatus 1700, or a component of the UE 102 or the UE apparatus 1700, such as the wireless baseband processor 1724, and/or the application processor 1706.
Referring to FIG. 9, the method 900 begins at block 902 where the UE 102 transmits to the network entity 104, a UE capability report for supporting UE capability for supporting lower layer centric mobility procedure. For example, referring to FIG. 3, the UE 102 transmits 310 a UE capability report for supporting lower layer centric mobility procedure.
At block 904, the UE 102 receives, from the network entity 104, a RRC configuration configuring candidate cell configuration (s) for a target cell. For example, referring to FIG. 3, the UE 102, based on the one or more UE capabilities, the UE 102 may receive 320 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations.
At block 906, the UE 102 receives, from the network entity 104, a DCI scheduling a CSC. For example, referring to FIG. 3, the UE 102 receives 324 a DCI scheduling a CSC.
At block 908, the UE 102 may transmit, to the network entity 104, a ACK for the CSC. For example, referring to FIG. 3, the UE 102 may transmit 340 an acknowledgement for the CSC.
At block 910, the UE 102 receives, from the network entity 104, another DCI.
At block 912, the UE 102 determines whether the information indicated by the other DCI is intended for a candidate cell (e.g., target cell) .
At block 914, the UE 102 performs action indicated by the other DCI.
In some implementations, during a second time duration, if the UE 102 performs a PDCCH monitoring in the source cell, the UE 102 could consider or determine DCI (s) received in the second time duration are always intended for the target cell (i.e., the candidate cell indicated in the CSC) . In one example, the UE 102 decodes the DCI based on the RRC configuration for the target cell. In one example, the UE 102 applies information indicated in DCI (s) (in which the UE 102 detected/received in the source cell) to the target cell (i.e., the candidate cell indicated in the CSC) .
In some implementations, during the second time duration, if the UE 102 considers or determines DCI (s) received in the second time duration are intended for the target cell (i.e., the candidate cell indicated in the CSC) , the UE 102 could perform one of the following behaviors: performs PDCCH monitoring in the source cell, based on search space (SS) set configuration (s) and control resource set (CORESET) configuration (s) for the source cell. However, for such case, the UE 102 could ignore or stop monitoring one or more DCI format (s) configured by search space set configuration (s) for the source cell. In some examples, the UE 102 could stop monitoring DCI format 1_0. In some examples, the UE 102 could stop monitoring DCI format 1_1 and/or 1_2. In some examples, the UE 102 could stop monitoring DCI format (s) related to UL grant (s) . In some examples, the UE 102 could stop monitoring DCI format (s) related to group control signal (DCI format 2_x) , e.g., DCI format 2_1. In some examples, the UE 102 could stop monitoring DCI format (s) different from that of the second DCI. For such case, the UE 102 could stop monitoring partial CORESET (s) configured by CORESET configuration (s) for the source cell. For such case, the UE 102 could stop monitoring partial SS (s) configured by search space set configuration (s) for the source cell.
In some implementations, during the second time duration, if the UE 102 considers or determines DCI (s) received in the second time duration are intended for the target cell (i.e., the candidate cell indicated in the CSC) , the UE 102 could also perform one of the following behaviors: interpret DCI fields in DCI (s) based on control resource set (CORESET) configuration (s) , BWP configuration (s) and serving cell configuration (s) for the target cell (i.e., the candidate cell indicated in the CSC) , where the UE 102 received the DCI (s) in the second time duration. However, for such case, the UE could ignore one or more DCI field (s) in the DCI (s) . For example, DCI field (s) related to data scheduling, e.g., Frequency domain resource assignment field, or Time domain resource assignment field.
In some implementations, during the second time duration, if the UE 102 considers or determines DCI (s) received in the second time duration are intended for the target cell (i.e., the candidate cell indicated in the CSC) , the UE 102 could also perform one of the following behaviors: If the UE receives a fifth DCI scheduling a CSC (which could indicate different information from that in the CSC scheduled by the second DCI) , the UE could replace information indicated in the CSC scheduled by the second DCI with the CSC scheduled by the fifth DCI.
In some implementations, if the UE considers or determines DCI (s) , in which the UE received in the second time duration, is intended for the target cell (i.e., the candidate cell indicated in the CSC) , it could imply that information indicated in these DCI (s) are intended for the target cell, e.g., beam indication.
FIG. 9 describes a method from a UE-side of a wireless communication link, whereas FIG. 10 describes another method from a UE-side of the wireless communication link.
Now turning to FIG. 10 which illustrates an example method 1000 for supporting lower layer centric mobility procedure implemented in the UE. The method 1000 can be implemented by UE 102 and network entity 104 depicted in FIG. 1. With reference to FIGs. 1 and 17, the method may be performed by the UE 102, the UE apparatus 1700, etc., which may include the memory 1724’ and which may correspond to the entire UE 102 or the UE apparatus 1700, or a component of the UE 102 or the UE apparatus 1700, such as the wireless baseband processor 1724, and/or the application processor 1706.
Referring to FIG. 10, the method 1000 begins at block 1002 where the UE 102 transmits to the network entity 104, a UE capability report for supporting UE capability for supporting lower layer centric mobility procedure. For example, referring to FIG. 3, the UE 102 transmits 310 a UE capability report for supporting lower layer centric mobility procedure.
At block 1004, the UE 102 receives, from the network entity 104, a RRC configuration configuring candidate cell configuration (s) for a target cell. For example, referring to FIG. 3, the UE 102, based on the one or more UE capabilities, the UE 102 may receive 320 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations.
At block 1006, the UE 102 receives, from the network entity 104, a DCI scheduling a CSC. For example, referring to FIG. 3, the UE 102 receives 324 a DCI scheduling a CSC.
At block 1008, the UE 102 may transmit, to the network entity 104, a ACK for the CSC. For example, referring to FIG. 3, the UE 102 may transmit 340 an acknowledgement for the CSC.
At block 1010, the UE 102 receives, from the network entity 104, another DCI. For example, referring to FIG. 4, the UE 102 receives 434 another DCI scheduling a CSC.
At block 1016, the UE 102 determines whether the other DCI schedules another CSC.
If the UE 102 determines the other DCI schedules another CSC, at block 1018, the UE 102 determines the information indicated by the another DCI is intended for the candidate cell indicated by the another CSC.
At block 1020, the UE 102 performs actions indicated by the DCI.
If the UE 102 determines the other DCI does not schedule another CSC, at block 1022, the UE 102 determines the information indicated by the other one DCI is intended for the source cell.
At block 1024, the UE 102 performs action indicated by the DCI.
In some implementations, during a second time duration, if the UE performs PDCCH monitoring in the source cell, based on whether the DCI (s) schedule a CSC, the UE could consider or determine whether DCI (s) received in the second time duration are intended for the source cell or the target cell or other candidate cell (s) . If the DCI (s) schedule a CSC, the DCI (s) are intended for candidate cell (s) , which could be the target cell or another one candidate cell; otherwise, the DCI (s) are intended for the source cell.
FIG. 10 describes a method from a UE-side of a wireless communication link, whereas FIG. 11 describes another method from a UE-side of the wireless communication link.
Now turning to FIG. 11 which illustrates an example method 1100 for supporting lower layer centric mobility procedure implemented in the UE. The method 1100 can be implemented by UE 102 and network entity 104 depicted in FIG. 1. With reference to FIGs. 1 and 17, the method may be performed by the UE 102, the UE apparatus 1700, etc., which may include the memory 1724’ and which may correspond to the entire UE 102 or the UE apparatus 1700, or a component of the UE 102 or the UE apparatus 1700, such as the wireless baseband processor 1724, and/or the application processor 1706.
Referring to FIG. 11, the method 1100 begins at block 1102 where the UE 102 transmits to the network entity 104, a UE capability report for supporting UE capability for supporting lower layer centric mobility procedure. For example, referring to FIG. 3, the UE 102 transmits 310 a UE capability report for supporting lower layer centric mobility procedure.
At block 1104, the UE 102 receives, from the network entity 104, a RRC configuration configuring candidate cell configuration (s) for a target cell. For example, referring to FIG. 3, the UE 102, based on the one or more UE capabilities, the UE 102 may receive 320 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations.
At block 1106, the UE 102 receives, from the network entity 104, a DCI scheduling a CSC. For example, referring to FIG. 3, the UE 102 receives 324 a DCI scheduling a CSC.
At block 1108, the UE 102 may transmit, to the network entity 104, a ACK for the CSC. For example, referring to FIG. 3, the UE 102 may transmit 340 an acknowledgement for the CSC.
At block 1111, the UE 102 receives, from the network entity 104, another DCI with a field. For example, referring to FIG. 4, the UE 102 receives 434 another DCI scheduling a CSC.
At block 1116, the UE 102 determines whether the field indicates that the other one DCI is intended for source cell or a candidate cell.
If the UE 102 determines the field indicates that the another one DCI is intended for a candidate cell, at block 1118, the UE determines the information indicated by the another one DCI is intended for the candidate cell indicated by the another one CSC.
At block 1120, the UE 102 performs actions indicated by the DCI.
If the UE 102 determines the field does not indicate that the other one DCI is intended for a candidate cell, at block 1122, the UE 102 determines the information indicated by the other one DCI is intended for the source cell.
At block 1124, the UE 102 performs actions indicated by the DCI.
In some implementations, during a second time duration, if the UE performs PDCCH monitoring in the source cell, based on indication of a field or bit (s) in the DCI (s) , the UE could consider or determine whether DCI (s) received in the second time duration are intended for the source cell or the target cell or other candidate cell (s) . The field or bit (s) in the DCI (s) could be used by the network entity 104 to indicate whether the DCI (s) are intended for the source cell or the target cell or other candidate cell (s) , which could be the target cell or another one candidate cell.
FIG. 11 describes a method from a UE-side of a wireless communication link, whereas FIG. 12 describes another method from a UE-side of the wireless communication link.
Now turning to FIG. 12 which illustrates an example method 1200 for supporting lower layer centric mobility procedure implemented in the UE. The method 1200 can be implemented by UE 102 and network entity 104 depicted in FIG. 1. With reference to FIGs. 1 and 17, the method may be performed by the UE 102, the UE apparatus 1700, etc., which may include the memory 1724’ and which may correspond to the entire UE 102 or the UE apparatus 1700, or a component of the UE 102 or the UE apparatus 1700, such as the wireless baseband processor 1724, and/or the application processor 1706.
Referring to FIG. 12, the method 1200 begins at block 1202 where the UE 102 transmits to the network entity 104, a UE capability report for supporting UE capability for supporting lower layer centric mobility procedure. For example, referring to FIG. 3, the UE 102 transmits 310 a UE capability report for supporting lower layer centric mobility procedure.
At block 1203, the UE 102 may transmit to the network entity 104, a UE capability report for supporting a maximum number of PDCCH candidates and/or Control Channel Elements (CCEs) the UE can detect in a slot/span. For example, referring to FIG. 3, the UE 102 transmits 310 a UE capability report for supporting lower layer centric mobility procedure.
At block 1204, the UE 102 receives, from the network entity 104, a RRC configuration configuring candidate cell configuration (s) for a target cell. For example, referring to FIG. 3, the UE 102, based on the one or more UE capabilities, the UE 102 may receive 320 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations.
At block 1206, the UE 102 receives, from the network entity 104, a DCI scheduling a CSC. For example, referring to FIG. 3, the UE 102 receives 324 a DCI scheduling a CSC.
At block 1208, the UE 102 may transmit, to the network entity 104, a ACK for the CSC. For example, referring to FIG. 3, the UE 102 may transmit 340 an acknowledgement for the CSC.
At block 1210, the UE 102 detects PDCCH candidates for the source cell and the target cell.
At block 1212, the UE 102 drops or does not detect partial PDCCH candidates based on one or more rules or steps if the number of PDCCH candidates or CCEs the UE needs to detect in a slot or span is larger than UE capability or a predefined threshold.
In some implementations, the UE 102 could monitor PDCCHs in a slot/span based on one or more step (s) , if the UE 102 performs PDCCH monitoring in the second time duration (or the first time duration) , and the UE 102 determines or detects that at least one of the following events: Event 1: the number of PDCCH candidates that the network entity 104 configures the UE 102 to monitor for source cell and target cell in a slot/span exceeds the third capability, or Event 2: the number of non-overlapped CCEs that the network entity 104 configures the UE 102 to monitor for source cell and target cell in a slot/span exceeds the sixth capability.
In some implementations, if one of the above events would occur, the following steps could be used by the UE 102 to determine which PDCCHs to monitor in a slot/span. Some PDCCHs could not be monitored by the UE 102 in the slot/span even they are configured by the network entity 104 to monitor in the slot/span. Step 1:PDCCHs monitored in common search space (CSS) in target cell. If more than one CSS, the UE 102 monitors the CSS with lowest SS index firstly and then other CSSs with higher SS index. Step 2: PDCCHs monitored in CSSs in source cell. If more than one CSS, the UE 102 monitors the CSS with lowest SS index firstly and then other CSSs with higher SS index. Step 3: PDCCHs monitored in UE-specific search space (USS) in target cell. If more than one USS, the UE 102 monitors the USS with lowest SS index firstly and then other USSs with higher SS index. Step 4: PDCCHs monitored in USSs in source cell. If more than one USS, the UE monitors the USS with lowest SS index firstly and then other USSs with higher SS index.
In some implementations, if one of the above events would occur, the UE 102 would monitor PDCCHs by Step 1. If none of Event 1 or Event 2 is achieved, the UE 102 monitor PDCCHs with Step 2, 3, 4 and so on, until one of Event 1 or Event 2 is achieved. In some implementations, if one of the above events would occur, the UE 102 would monitor PDCCHs by Step 1. If none of Event 1 or Event 2 is achieved, the UE monitor PDCCHs with Step 3, 2, 4 and so on, until one of Event 1 or Event 2 is achieved.
In some implementations, if one of the above events would occur, the UE 102 would monitor PDCCHs by Step 2. If none of Event 1 or Event 2 is achieved, the UE 102 monitor PDCCHs with Step 1, 4, 3 and so on, until one of Event 1 or Event 2 is achieved.
It is noted that other order combination of the steps is not precluded. In some implementations, if one of the above events would occur, the UE 102 would monitor PDCCHs by Step 2. If none of Event 1 or Event 2 is achieved, the UE 102 monitor PDCCHs with Step 4, 1, 3 and so on, until one of Event 1 or Event 2 is achieved. In some implementations, the UE 102 could not monitor all PDCCHs mentioned in a Step. For example, assume the UE 102 uses Steps order: 1, 2, 3, 4, and in the target cell there are more than one USS configured to monitor: USS#1, USS#2, USS#3. If the total PDCCH candidates exceeds the third capability after the UE 102 selects USS#2 to monitor, the UE 102 would not monitor USS#2 and USS#3.
FIG. 12 describes a method from a UE-side of a wireless communication link, whereas FIG. 13 describes another method from a UE-side of the wireless communication link.
Now turning to FIG. 13 which illustrates an example method 1300 for supporting lower layer centric mobility procedure implemented in the UE. The method 1300 can be implemented by UE 102 and network entity 104 depicted in FIG. 1. With reference to FIGs. 1 and 17, the method may be performed by the UE 102, the UE apparatus 1700, etc., which may include the memory 1724’ and which may correspond to the entire UE 102 or the UE apparatus 1700, or a component of the UE 102 or the UE apparatus 1700, such as the wireless baseband processor 1724, and/or the application processor 1706.
Referring to FIG. 13, the method 1300 begins at block 1302 where the UE 102 transmits to the network entity 104, a UE capability report for supporting UE capability for supporting lower layer centric mobility procedure. For example, referring to FIG. 3, the UE 102 transmits 310 a UE capability report for supporting lower layer centric mobility procedure.
At block 1303, the UE 102 may transmit to the network entity 104, a UE capability report for supporting a maximum number of PDCCH candidates and/or Control Channel Elements (CCEs) the UE can detect in a slot/span. For example, referring to FIG. 3, the UE 102 transmits 310 a UE capability report for supporting lower layer centric mobility procedure.
At block 1304, the UE 102 receives, from the network entity 104, a RRC configuration configuring candidate cell configuration (s) for a target cell. For example, referring to FIG. 3, the UE 102, based on the one or more UE capabilities, the UE 102 may receive 320 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations.
At block 1306, the UE 102 receives, from the network entity 104, a DCI scheduling a CSC. For example, referring to FIG. 3, the UE 102 receives 324 a DCI scheduling a CSC.
At block 1308, the UE 102 may transmit, to the network entity 104, a ACK for the CSC. For example, referring to FIG. 3, the UE 102 may transmit 340 an acknowledgement for the CSC.
At block 1311, the UE 102 detects PDCCH candidates for the target cell only. The UE 102 stops detecting PDCCH candidates for the source cell.
In some implementations, if the network entity 104 indicates/configures that the UE performs PDCCH monitoring in the second time duration (or the first time duration) , the network entity 104 makes sure to configure or indicate that the UE does not need to monitor PDCCH candidates for target cell and those of source cell in the same slot/span. This could imply that PDCCH monitoring of target cell and PDCCH monitoring of source cell is performed in different slot/span (i.e., in a TDM way) .
In some implementations, the network entity 104 can configure or indicate the UE 102 a gap duration for target cell. The network entity 104 can configure at least one of the following for the gap duration: starting slot (or symbol) , duration length, periodicity, slot offset (or symbol offset) . The UE 102 could monitor PDCCH of target cell only during the gap duration. In some cases, the starting slot (or symbol) and/or the slot offset (or symbol offset) of SS (s) /CORESET (s) of the target cell is with reference to the gap duration or the start of the gap duration.
In some implementations, the network entity 104 configures the gap duration in a candidate cell configuration or a configuration not used for the serving cell (or the source cell) . In some other implementations, the network entity 104 configures the gap duration in configuration of the serving cell or the source cell (e.g., ServingCellConfig) .
In some implementations, if the network entity 104 indicates/configures that the UE performs PDCCH monitoring in the second time duration (or the first time duration) , the network entity 104 makes sure to configure or indicated that the number of PDCCH candidates that the UE 102 needs to monitor for source cell and target cell in a slot/span does not exceed the third capability. In some implementations, if the network entity 104 indicates/configures that the UE 102 performs PDCCH monitoring in the second time duration (or the first time duration) , the network entity 104 makes sure that the number of non-overlapped CCEs that the UE 102 needs to monitor for source cell and target cell in a slot/span does not exceed the sixth capability. In some cases, the PDCCH monitoring of target cell and PDCCH monitoring of source cell could be performed in the same slot/span. In some other cases, the PDCCH monitoring of target cell and PDCCH monitoring of source cell could be performed in different slot/span.
In some implementations, the UE 102 stops performing PDCCH monitoring in the second time duration (or the first time duration) . In some cases, the network entity 104 could indicate or configure the UE 102 to stop performing PDCCH monitoring in the second time duration (or the first time duration) . In some cases, the UE 102 could still maintain active TCI states in the serving cell or the source cell in the second time duration (or the first time duration) , even the UE 102 stops performing PDCCH monitoring in the second time duration (or the first time duration) .
In some implementations, configuration (s) of SS (s) and/or CORESET (s) for monitoring PDCCH for target cell or a candidate cell could be configured in corresponding candidate cell configuration. In some other implementations, configuration (s) of SS (s) and/or CORESET (s) for monitoring PDCCH for target cell or a candidate cell could be configured in configuration of the serving cell or the source cell (e.g., ServingCellConfig) .
FIG. 13 describes a method from a UE-side of a wireless communication link, whereas FIG. 14 describes a method from a network entity-side of the wireless communication link.
Now turning to FIG. 14 which illustrates an example method 1400 for supporting lower layer centric mobility procedure implemented in the network entity 104. FIG. 14 shows an example how the network entity 104 transmits PDCCH (s) or DCI (s) to the UE 102, with considering limitation of maximum monitored PDCCH candidates.
The method 1400 can be implemented by UE 102 and network entity 104 depicted in FIG. 1. With reference to FIGs. 1 and 18, the method may be performed by one or more network entities 104, which may correspond to a base station or a unit of the base station, such as the RU 106, the DU 108, the CU 110, an RU processor 1806, a DU processor 1826, a CU processor 1846, etc. The one or more network entities 104 may include memory 1806’/1826’/1846’, which may correspond to an entirety of the one or more network entities 104, or a component of the one or more network entities 104, such as the RU processor 1806, the DU processor 1826, or the CU processor 1846.
Referring to FIG. 14, the method 1400 begins at block 1402 where the network entity 104 receives, from the UE 102, a UE capability report for supporting UE capability for supporting lower layer centric mobility procedure. For example, referring to FIG. 3, the network entity receives 310, from the UE 102, a UE capability report for supporting lower layer centric mobility procedure.
At block 1403, the network entity 104 receives, from the UE 102, a UE capability report for supporting a maximum number of PDCCH candidates and/or Control Channel Elements (CCEs) the UE can detect in a slot/span. For example, referring to FIG. 3, the network entity receives 310, from the UE 102, a UE capability report for supporting lower layer centric mobility procedure.
At block 1404, the network entity 104, transmits, to the UE 102, a RRC configuration configuring candidate cell configuration (s) for a target cell. For example, referring to FIG. 3, the network entity 104, based on the one or more UE capabilities, transmits 320 to the UE 102 a RRC configuration to enable function of lower layer centric mobility procedure and/or configure candidate cell configurations.
At block 1405, the network entity 104 determines a first amount of PDCCH candidates for the source cell, which can be used to transmit DCI (s) to the UE, in a slot or a span, based on UE capability or predefined limitation.
At block 1407, the network entity 104 transmits, to the UE, a DCI scheduling a CSC, where the CSC indicates a target cell from configured candidate cell (s) , and the DCI is carried via one of the first amount of PDCCH candidates.
At block 1408, the network entity 104 receives, from the UE 102, a ACK for the CSC.
At block 1409, the network entity 104 determines a second amount of PDCCH candidates for the source cell and/or the target cell, which can be used to transmit DCI (s) to the UE, in a slot or a span, based on UE capability or predefined limitation.
At block 1411, the network entity 104 transmits, to the UE 102, another one DCI, where the other one DCI is carried via one of the second amount of PDCCH candidates.
In some implementations, the UE 102 reports a first capability to the network entity 104. The first capability could indicate or be used to calculate a maximum number of PDCCH candidates the UE 102 can monitor for source cell per slot/span. In some implementations, the UE reports a second capability to the network entity 104. The second capability could indicate or be used to calculate a maximum number of PDCCH candidates the UE 102 can monitor for target cell per slot/span. In some implementations, the UE reports a third capability to the network entity 104. The third capability could indicate or be used to calculate a maximum number of PDCCH candidates the UE can monitor per slot/span. In some cases, the third capability could indicate or be used to calculate a maximum number of PDCCH candidates the UE 102 can monitor across/for source cell and target cell per slot/span. In some cases, the third capability could indicate or be used to calculate a maximum number of PDCCH candidates the UE 102 can monitor in per slot/span, regardless of these PDCCH candidates are for source cell or target cell.
In some implementations, the first capability could be equal to the third capability. In some implementations, the second capability could be equal to the third capability. In some implementations, the first capability plus the second capability could be equal to the third capability.
In some implementations, the first capability could consider all component carriers (CCs) in source cell. In some implementations, the second capability could consider all component carriers (CCs) in target cell. In some implementations, the third capability could consider all component carriers (CCs) in source cell and target cell.
In some implementations, the UE 102 reports a fourth capability to the network entity 104. The fourth capability could indicate or be used to calculate a maximum number of non-overlapped Control Channel Elements (CCEs) the UE 102 can monitor for source cell per slot/span. In some implementations, the UE 102 reports a fifth capability to the network entity 104. The fifth capability could indicate or be used to calculate a maximum number of non-overlapped CCEs the UE 102 can monitor for target cell per slot/span. In some implementations, the UE 102 reports a sixth capability to the network entity 104. The sixth capability could indicate or be used to calculate a maximum number of non-overlapped CCEs the UE 102 can monitor per slot/span. In some cases, the sixth capability could indicate or be used to calculate a maximum number of non-overlapped CCEs the UE 102 can monitor across/for source cell and target cell per slot/span. In some cases, the sixth capability could indicate or be used to calculate a maximum number of non-overlapped CCEs the UE 102 can monitor per slot/span, regardless of these CCEs (or corresponding PDCCH candidates) are for source cell or target cell.
In some implementations, the fourth capability could be equal to the sixth capability. In some implementations, the fifth capability could be equal to the sixth capability. In some implementations, the fourth capability plus the fifth capability could be equal to the sixth capability.
In some implementations, the fourth capability could consider all component carriers (CCs) in source cell. In some implementations, the fifth capability could consider all component carriers (CCs) in target cell. In some implementations, the sixth capability could consider all component carriers (CCs) in source cell and target cell.
In some implementations, some of the UE capabilities above, i.e., from the first to the sixth capability, may be predefined. In one example, the maximum number of PDCCH candidates per slot/span across the source cell and target cell is predefined as 44.
In some implementations, CCEs for PDCCH candidates are non-overlapped if they correspond to one of the followings: different CORESET indexes, or different first symbols for the reception of the respective PDCCH candidates.
FIG. 15 illustrates a flowchart 1500 of a method of wireless communication at a UE. The method 1500 can be implemented by UE 102 and network entity 104 depicted in FIG. 1. With reference to FIGs. 1 and 17, the method may be performed by the UE 102, the UE apparatus 1700, etc., which may include the memory 1724’ and which may correspond to the entire UE 102 or the UE apparatus 1700, or a component of the UE 102 or the UE apparatus 1700, such as the wireless baseband processor 1724, and/or the application processor 1706.
At block 1502, the UE 102 receives, from a network entity 104, a cell switch command, CSC, for triggering a lower layer centric mobility procedure, LLCMP, which switches from communicating via a source cell to communicating via a target cell to communicating via a target cell among one or more candidate cells. For example, referring to FIG. 3, the UE 102 receives 324 a DCI scheduling a CSC.
At block 1504, the UE 102 transmits, to the network entity 104, an acknowledgement, ACK, after a first time interval from the receiving. For example, referring to FIG. 3, the UE 102 may transmit 340 an acknowledgement for the CSC.
At block 1506, the UE 102 performs the LLCMP, which is completed after a second time interval from the transmitting or from an action time of the CSC.
At block 1508, the UE 102 selectively uses beam-related information received via a control channel during at least one of the first time interval and the second time interval.
At block 1510, the UE 102 reports, to the network entity 104, UE’s capability to perform the LLCMP.
At block 1512, the UE 102 receives from the network entity, a radio resource control message configuring the one or more candidate cells.
At block 1514, the UE 102, if the beam-related information is received during the first time interval, applies the beam-related information to the source cell.
At block 1516, the UE 102, if the beam-related information is received together with the CSC, ignores the beam-related information.
At block 1518, the UE 102 receives the beam-related information in a control message via the control channel, the control message including also the CSC.
At block 1520, the UE 102 decodes a bandwidth part, BWP, field of the control message.
At block 1522, the UE 102 selectively switches a BWP in the target cell according to the BWP field and a BWP configuration for the target cell.
At block 1524, the UE 102 overwrites the CSC with a later-received CSC during the first interval.
At block 1526, the UE 102 applies the beam-related information to the target cell if the information is received during the second interval.
At block 1528, the UE 102 associates the beam-related information with the source cell if the information is received during the second interval in a message that does not include the later-received CSC.
At block 1530, the UE 102 associates the beam-related information with the target cell if the information is received during the second interval in a message that includes the later-received CSC.
At block 1532, the UE 102 detects a bit or a field in the DCI that indicates the beam-related information is for the target cell or the source cell if the information is received during the second interval.
At block 1534, the UE 102 detects a predefined number of candidate control messages related to the source cell and/or the target cell received in a slot or in a span via the control channel.
At block 1536, the UE 102, after the detecting of the predefined number of candidate control messages, stops detecting candidate control messages related to the source cell or both to the source cell and to the target cell in the slot or in the span.
At block 1538, the UE 102 transmits, to the network entity, the predefined number.
FIG. 15 describes a method from a UE-side of a wireless communication link, whereas FIG. 16 describes a method from a network-side of the wireless communication link.
FIG. 16 is a flowchart 1600 of a method of wireless communication at a network entity. With reference to FIGs. 1 and 18, the method may be performed by one or more network entities 104, which may correspond to a base station or a unit of the base station, such as the RU 106, the DU 108, the CU 110, an RU processor 1806, a DU processor 1826, a CU processor 1846, etc. The one or more network entities 104 may include memory 1806’/1826’/1846’, which may correspond to an entirety of the one or more network entities 104, or a component of the one or more network entities 104, such as the RU processor 1806, the DU processor 1826, or the CU processor 1846.
At block 1602, the network entity 104 transmits, to a UE a cell switch command, CSC, for scheduling a centric mobility procedure, LLCMP, which switches from communicating via a source cell to communicating via a target cell among one or more candidate cells.
At block 1604, the network entity 104 receives, from the UE 102, an acknowledgement, ACK, after a first time interval that corresponds to a first time duration between the UE receiving the CSC and transmitting the ACK.
At block 1606, the network entity 104 receives transmits, to the UE 102, a message including beam-related information during the first time interval or a second time interval corresponding to a second time duration between a transmission of the ACK and receiving an indication that the UE has completed the LLCM procedure, the message being formatted depending on whether the transmitting occurs during the first time interval or during the second time interval to facilitate UE’s interpretation of the beam-related information being related to the source cell or to the target cell.
At block 1608, the network entity 104 receives, from the UE 102, an indication the UE is able to perform the LLCMP.
At block 1610, the network entity 104 transmits, to the UE 102, a radio resource control message configuring the one or more candidate cells.
At block 1612, the network entity 104 limits a number of LLCMP-related control message candidates transmitted in a slot or in a span during the second time interval to a predefined threshold.
It is noted that throughout this disclosure, a neighboring cell can be referred to or replaced with one or some of the followings: (1) an on-serving cell, (2) a cell with a physical cell ID (PCI) different that of the serving cell, (3) a TRP associated with a PCI different from that of the serving cell.
It is noted that throughout this disclosure, action time of a signal could mean the actual timing when the signal is applicable or takes effect, which could be later than the timing of receiving the signal.
It is noted that throughout this disclosure, a joint TCI state can be referred to or replaced with at least one of the followings: (1) a beam applicable for both one or more DL and UL transmission (s) , e.g., one or more DL channel, UL channel, DL RS and/or UL RS, (2) a spatial filter for transmission and/or reception, (3) a spatial parameters for transmission and/or reception, (4) a spatial relationship for transmission and/or reception, (5) a spatial assumption for transmission and/or reception.
It is noted that throughout this disclosure, a “DL mode” or a “DL-only TCI state mode” could mean or be referred to at least one of the followings: (1) TCI field (s) or indicated TCI state (s) in a DCI format may refer/map to DL TCI state pool (joint TCI state pool) , and/or (2) beam indication (s) or indicated TCI state (s) are applied for (only) receiving DL transmission.
A UE apparatus 1702, as described in FIG. 17, may perform the method of flowchart 1500. The one or more network entities 104, as described in FIG. 18, may perform the method of flowchart 1600.
FIG. 17 is a diagram 1700 illustrating an example of a hardware implementation for a UE apparatus 1702. The UE apparatus 1702 may be the UE 102, a component of the UE 102, or may implement UE functionality. The UE apparatus 1702 may include an application processor 1706, which may have on-chip memory 1706’ . In examples, the application processor 1706 may be coupled to a secure digital (SD) card 1708 and/or a display 1710. The application processor 1706 may also be coupled to a sensor (s) module 1712, a power supply 1714, an additional module of memory 1716, a camera 1718, and/or other related components. For example, the sensor (s) module 1712 may control a barometric pressure sensor/altimeter, a motion sensor such as an inertial management unit (IMU) , a gyroscope, accelerometer (s) , a light detection and ranging (LIDAR) device, a radio-assisted detection and ranging (RADAR) device, a sound navigation and ranging (SONAR) device, a magnetometer, an audio device, and/or other technologies used for positioning.
The UE apparatus 1702 may further include a wireless baseband processor 1726, which may be referred to as a modem. The wireless baseband processor 1726 may have on-chip memory 1726'. Along with, and similar to, the application processor 1706, the wireless baseband processor 1726 may also be coupled to the sensor (s) module 1712, the power supply 1714, the additional module of memory 1716, the camera 1718, and/or other related components. The wireless baseband processor 1726 may be additionally coupled to one or more subscriber identity module (SIM) card (s) 1720 and/or one or more transceivers 1730 (e.g., wireless RF transceivers) .
Within the one or more transceivers 1730, the UE apparatus 1702 may include a Bluetooth module 1732, a WLAN module 1734, an SPS module 1736 (e.g., GNSS module) , and/or a cellular module 1738. The Bluetooth module 1732, the WLAN module 1734, the SPS module 1736, and the cellular module 1738 may each include an on-chip transceiver (TRX) , or in some cases, just a transmitter (TX) or just a receiver (RX) . The Bluetooth module 1732, the WLAN module 1734, the SPS module 1736, and the cellular module 1738 may each include dedicated antennas and/or utilize antennas 1740 for communication with one or more other nodes. For example, the UE apparatus 1702 can communicate through the transceiver (s) 1730 via the antennas 1740 with another UE 102 (e.g., sidelink communication) and/or with a network entity 104 (e.g., uplink/downlink communication) , where the network entity 104 may correspond to a base station or a unit of the base station, such as the RU 106, the DU 108, or the CU 110.
The wireless baseband processor 1726 and the application processor 1706 may each include a computer-readable medium /memory 1726', 1706', respectively. The additional module of memory 1716 may also be considered a computer-readable medium /memory. Each computer-readable medium /memory 1726', 1706', 1716 may be non-transitory. The wireless baseband processor 1726 and the application processor 1706 may each be responsible for general processing, including execution of software stored on the computer-readable medium /memory 1726', 1706', 1716. The software, when executed by the wireless baseband processor 1726 /application processor 1706, causes the wireless baseband processor 1726 /application processor 1706 to perform the various functions described herein. The computer-readable medium /memory may also be used for storing data that is manipulated by the wireless baseband processor 1726 /application processor 1706 when executing the software. The wireless baseband processor 1726 /application processor 1706 may be a component of the UE 102. The UE apparatus 1702 may be a processor chip (e.g., modem and/or application) and include just the wireless baseband processor 1726 and/or the application processor 1706. In other examples, the UE apparatus 1702 may be the entire UE 102 and include the additional modules of the apparatus 1702.
As discussed, the monitoring and decoding component 140 is configured to receive, from a network entity, a cell switch command, CSC, for scheduling a lower layer centric mobility procedure, LLCMP, for switching communication via a source cell to a target cell among one or more candidate cells; transmit, to the network entity, an acknowledgement, ACK, after a first time interval from the receiving; perform the LLCMP after a second time interval from the transmitting; and selectively use beam-related information received via a control channel during at least one of the first time interval and the second time interval.
The monitoring and decoding component 140 may be within the application processor 1706 (e.g., at 140a) , the wireless baseband processor 1726 (e.g., at 140b) , or both the application processor 1706 and the wireless baseband processor 1726. The monitoring and decoding component 140a-140b may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by one or more processors configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by the one or more processors, or a combination thereof.
FIG. 18 is a diagram 1800 illustrating an example of a hardware implementation for one or more network entities 104. The one or more network entities 104 may be a base station, a component of a base station, or may implement base station functionality. The one or more network entities 104 may include, or may correspond to, at least one of the RU 106, the DU, 108, or the CU 110. The CU 110 may include a CU processor 1846, which may have on-chip memory 1846'. In some aspects, the CU 110 may further include an additional module of memory 1856 and/or a communications interface 1848, both of which may be coupled to the CU processor 1846. The CU 110 can communicate with the DU 108 through a midhaul link 162, such as an F1 interface between the communications interface 1848 of the CU 110 and a communications interface 1828 of the DU 108.
The DU 108 may include a DU processor 1826, which may have on-chip memory 1826'. In some aspects, the DU 108 may further include an additional module of memory 1836 and/or the communications interface 1828, both of which may be coupled to the DU processor 1826. The DU 108 can communicate with the RU 106 through a fronthaul link 160 between the communications interface 1828 of the DU 108 and a communications interface 1808 of the RU 106.
The RU 106 may include an RU processor 1806, which may have on-chip memory 1806'. In some aspects, the RU 106 may further include an additional module of memory 1816, the communications interface 1808, and one or more transceivers 1830, all of which may be coupled to the RU processor 1806. The RU 106 may further include antennas 1840, which may be coupled to the one or more transceivers 1830, such that the RU 106 can communicate through the one or more transceivers 1830 via the antennas 1840 with the UE 102.
The on-chip memory 1806', 1826', 1846' and the additional modules of memory 1816, 1836, 1856 may each be considered a computer-readable medium /memory. Each computer-readable medium /memory may be non-transitory. Each of the processors 1806, 1826, 1846 is responsible for general processing, including execution of software stored on the computer-readable medium /memory. The software, when executed by the corresponding processor (s) 1806, 1826, 1846 causes the processor (s) 1806, 1826, 1846 to perform the various functions described herein. The computer-readable medium /memory may also be used for storing data that is manipulated by the processor (s) 1806, 1826, 1846 when executing the software. In examples, the mobility scheduler component 150 may sit at any of the one or more network entities 104, such as at the CU 110; both the CU 110 and the DU 108; each of the CU 110, the DU 108, and the RU 106; the DU 108; both the DU 108 and the RU 106; or the RU 106.
As discussed, the mobility scheduler component 150 is configured to transmit, to a user equipment (UE) , a cell switch command, CSC, for scheduling a centric mobility procedure, LLCMP, which switches from communicating via a source cell to communicating via a target cell among one or more candidate cells; receive, from the UE, an acknowledgement, ACK, after a first time interval that corresponds to a first time duration between the UE receiving the CSC and transmitting the ACK; and transmit, to the UE, a message including beam-related information during the first time interval or a second time interval corresponding to a second time duration between a transmission of the ACK and receiving an indication that the UE has completed the LLCM procedure, the message being formatted depending on whether the transmitting occurs during the first time interval or during the second time interval to facilitate UE’s interpretation of the beam-related information being related to the source cell or to the target cell.
The mobility scheduler component 150 may be within one or more processors of the one or more network entities 104, such as the RU processor 1806 (e.g., at 150a) , the DU processor 1826 (e.g., at 150b) , and/or the CU processor 1846 (e.g., at 150c) . The mobility scheduler component 150a-150c may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by one or more processors 1806, 1826, 1846 configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by the one or more processors 1806, 1826, 1846, or a combination thereof.
The specific order or hierarchy of blocks in the processes and flowcharts disclosed herein is an illustration of example approaches. Hence, the specific order or hierarchy of blocks in the processes and flowcharts may be rearranged. Some blocks may also be combined or deleted. Dashed lines may indicate optional elements of the diagrams. The accompanying method claims present elements of the various blocks in an example order, and are not limited to the specific order or hierarchy presented in the claims, processes, and flowcharts.
The detailed description set forth herein describes various configurations in connection with the drawings and does not represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough explanation of various concepts. However, these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.
Aspects of wireless communication systems, such as telecommunication systems, are presented with reference to various apparatuses and methods. These apparatuses and methods are described in the following detailed description and are illustrated in the accompanying drawings by various blocks, components, circuits, processes, call flows, systems, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.
An element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems-on-chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other similar hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software, which may be referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, or any combination thereof.
If the functionality described herein is implemented in software, the functions may be stored on, or encoded as, one or more instructions or code on a computer-readable medium, such as a non-transitory computer-readable storage medium. Computer-readable media includes computer storage media and can include a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of these types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer. Storage media may be any available media that can be accessed by a computer.
Aspects, implementations, and/or use cases described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, the aspects, implementations, and/or use cases may come about via integrated chip implementations and other non-module-component based devices, such as end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, artificial intelligence (AI) -enabled devices, machine learning (ML) -enabled devices, etc. The aspects, implementations, and/or use cases may range from chip-level or modular components to non-modular or non-chip-level implementations, and further to aggregate, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more techniques described herein.
Devices incorporating the aspects and features described herein may also include additional components and features for the implementation and practice of the claimed and described aspects and features. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes, such as hardware components, antennas, RF-chains, power amplifiers, modulators, buffers, processor (s) , interleavers, adders/summers, etc. Techniques described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc., of varying configurations.
The description herein is provided to enable a person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not limited to the aspects described herein, but are to be interpreted in view of the full scope of the present disclosure consistent with the language of the claims.
Reference to an element in the singular does not mean “one and only one” unless specifically stated, but rather “one or more. ” Terms such as “if, ” “when, ” and “while” do not imply an immediate temporal relationship or reaction. That is, these phrases, e.g., “when, ” do not imply an immediate action in response to or during the occurrence of an action, but simply imply that if a condition is met then an action will occur, but without requiring a specific or immediate time constraint for the action to occur. The terms “may” , “might” , and “can” , as used in this disclosure, often carry certain connotations. For example, “may” refers to a permissible feature that may or may not occur, “might” refers to a feature that probably occurs, and “can” refers to a capability (e.g., capable of) . The phrase “For example” often carries a similar connotation to “may” and, therefore, “may” is sometimes excluded from sentences that include “for example” or other similar phrases.
Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C” or “one or more of A, B, or C” include any combination of A, B, and/or C, such as A and B, A and C, B and C, or A and B and C, and may include multiples of A, multiples of B, and/or multiples of C, or may include A only, B only, or C only. Sets should be interpreted as a set of elements where the elements number one or more.
Unless otherwise specifically indicated, ordinal terms such as “first” and “second” do not necessarily imply an order in time, sequence, numerical value, etc., but are used to distinguish between different instances of a term or phrase that follows each ordinal term. Reference numbers, as used in the specification and figures, are sometimes cross-referenced among drawings to denote same or similar features. A feature that is exactly the same in multiple drawings may be labeled with the same reference number in the multiple drawings. A feature that is similar among the multiple drawings, but not exactly the same, may be labeled with reference numbers that have different leading numbers, but have one or more of the same trailing numbers (e.g., 206, 306, 406, etc., may refer to similar features in the drawings) . Sometimes an “X” is used to universally denote multiple variations of a feature. For instance, “X06” can universally refer to all reference numbers that end in “06” (e.g., 206, 306, 406, etc. ) .
Structural and functional equivalents to elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are encompassed by the claims. The words “module, ” “mechanism, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ” As used herein, the phrase “based on”shall not be construed as a reference to a closed set of information, one or more conditions, one or more factors, or the like. In other words, the phrase “based on A” , where “A” may be information, a condition, a factor, or the like, shall be construed as “based at least on A” unless specifically recited differently.
The following examples are illustrative only and may be combined with other examples or teachings described herein, without limitation.
Example 1 is a method of wireless communication at a UE, including: receiving, from a network entity, a cell switch command, CSC, for triggering a lower layer centric mobility procedure, LLCMP, which switches from communicating via a source cell to communicating via a target cell among one or more candidate cells; transmitting, to the network entity, an acknowledgement, ACK, after a first time interval from the receiving; performing the LLCMP, which is completed after a second time interval from the transmitting or from an action time of the CSC; and selectively using information received via a control channel during at least one of the first time interval and the second time interval.
Example 2 may be combined with Example 1 and includes that the performing of the LLCMP is based on the CSC and the information, at least one of the CSC or the information being received in a downlink control information, DCI, format.
Example 3 may be combined with Example 1 or Example 2 and includes that the information comprises at least one of a beam identifier or a bandwidth part, BWP, identifier.
Example 4 may be combined with Example 3 and includes that the beam identifier is a transmission configuration indicator, TCI, state.
Example 5 may be combined with any Examples 1-4 and further includes at least one of: reporting, to the network entity, UE’s capability to perform the LLCMP; and receiving, from the NE, a radio resource control message configuring the one or more candidate cells.
Example 6 may be combined with any of Examples 1-5 and further includes if the information is received during the first time interval, applying the information to the source cell; and if the information is received together with the CSC, ignoring the information.
Example 7 may be combined with any of Examples 1-6 and that the receiving of the CSC includes receiving the information in a control message via the control channel, the control message including also the CSC, and decoding a bandwidth part, BWP, field of the control message; and selectively switching a BWP in the target cell according to the BWP field and a BWP configuration for the target cell.
Example 8 may be combined with Example 7 and includes that the decoding and applying the BPW field includes detecting, in the control message, a bit or a field that indicates the BWP field is for the target cell.
Example 9 may be combined with any of Examples 1-8 and further includes overwriting the CSC with a later-received.
Example 10 may be combined with any of Examples 1-7 and Example 9 and further includes applying the information to the target cell if the information is received during the second interval.
Example 11 may be combined with any of Examples 1-6 and further includes associating the information with the source cell if the information is received during the second interval in a message that does not include the later-received CSC; or.
associating the information with the target cell if the information is received during the second interval in a message that includes the later-received CSC
Example 12 may be combined with any of Examples 1-10 and further includes detecting a bit or a field in the DCI that indicates the information is for the target cell or the source cell if the information is received during the second interval.
Example 13 may be combined with any of Examples 1-11 and further includes detecting a predefined number of candidate control messages related to the source cell and/or the target cell received in a slot or in a span via the control channel; and after the detecting of the predefined number of candidate control messages, stop detecting candidate control messages related to the source cell or both to the source cell and to the target cell in the slot or in the span.
Example 14 may be combined with Example 13 and further includes transmitting, to the network entity, the predefined number.
Example15 may be combined with any of Examples 1-5 and further includes that the information comprises a BWP field, indicating an active BWP that has a same frequency range as a bandwidth used to transmit a synchronization signal block, SSB, for an inter-cell beam management, ICBM.
Example 16 is a method of wireless communication at a network entity, including: transmitting, to a user equipment (UE) , a cell switch command, CSC, for scheduling a centric mobility procedure, LLCMP, which switches from communicating via a source cell to communicating via a target cell among one or more candidate cells; receiving, from the UE, an acknowledgement, ACK, after a first time interval that corresponds to a first time duration between the UE receiving the CSC and transmitting the ACK; and transmitting, to the UE, a message including beam-related information during the first time interval or a second time interval corresponding to a second time duration between a transmission of the ACK and receiving an indication that the UE has completed the LLCM procedure, the message being formatted depending on whether the transmitting occurs during the first time interval or during the second time interval to facilitate UE’s interpretation of the beam-related information being related to the source cell or to the target cell.
Example 17 may be combined with Example 16 and further includes receiving, from the UE, an indication the UE is able to perform the LLCMP; and transmitting, to the UE, a radio resource control message configuring the one or more candidate cells.
Example 18 may be combined with any of Examples 16-17 and further includes limiting a number of LLCMP-related control message candidates transmitted in a slot or in a span during the second time interval to a predefined threshold.
Example 19 is an apparatus for wireless communication for implementing a method as in any of examples 1-18.
Example 20 is an apparatus for wireless communication including means for implementing a method as in any of examples 1-18.
Example 21 is a non-transitory computer-readable medium storing computer executable code, the code when executed by a processor causes the processor to implement a method as in any of examples 1-18.

Claims

A method of wireless communication performed by a user equipment, the method comprising:

receiving (1502) , from a network entity, a cell switch command, CSC, for triggering a lower layer centric mobility procedure, LLCMP, which switches from communicating via a source cell to communicating via a target cell among one or more candidate cells;

transmitting (1504) , to the network entity, an acknowledgement, ACK, after a first time interval from the receiving;

performing (1506) the LLCMP, which is completed after a second time interval from the transmitting or from an action time of the CSC; and

selectively using (1508) information received via a control channel during at least one of the first time interval and the second time interval.
The method of any of claims 1, wherein the performing of the LLCMP is based on the CSC and the information, at least one of the CSC or the information being received in a downlink control information, DCI, format.
The method of any of claims 1 or 2, wherein the information comprises at least one of a beam identifier or a bandwidth part, BWP, identifier.
The method of claim 3, wherein the beam identifier is a transmission configuration indicator, TCI, state.
The method of any of claim 1-4, the method further comprising at least one of:

reporting, to the network entity, UE’s capability to perform the LLCMP; and

receiving, from the network entity, a radio resource control message configuring the one or more candidate cells.
The method of any of claims 1-5, further comprising:

if the information is received during the first time interval, applying the information to the source cell; and

if the information is received together with the CSC, ignoring the information.
The method of any of claims 1-6, wherein the receiving of the CSC comprises:

receiving the information in a control message via the control channel, the control message including also the CSC; and

decoding a bandwidth part, BWP, field of the control message; and

selectively switching a BWP in the target cell according to the BWP field and a BWP configuration for the target cell.
The method of any of claims 1-7, further comprising:

overwriting the CSC with a later-received CSC during the first interval.
The method of any of claims 1-8, further comprising:

applying the information to the target cell if the information is received during the second interval.
The method of any of claims 1-6, the method further comprising:

associating the information with the source cell if the information is received during the second interval in a message that does not include the later-received CSC; or

associating the information with the target cell if the information is received during the second interval in a message that includes the later-received CSC.
The method of any of claims 1-10, further comprising:

detecting a bit or a field in the DCI that indicates the information is for the target cell or the source cell if the -information is received during the second interval.
The method of any of claims 1-11, further comprising:

detecting a predefined number of candidate control messages related to the source cell and/or the target cell received in a slot or in a span via the control channel; and

after the detecting of the predefined number of candidate control messages, stop detecting candidate control messages related to the source cell or both to the source cell and to the target cell in the slot or in the span.
The method of claim 12, further comprising:

transmitting, to the network entity, the predefined number.
A method of wireless communication at a network entity, the method comprising:

transmitting (1602) , to a user equipment (UE) , a cell switch command, CSC, for scheduling a centric mobility procedure, LLCMP, which switches from communicating via a source cell to communicating via a target cell among one or more candidate cells;

receiving (1604) , from the UE, an acknowledgement, ACK, after a first time interval that corresponds to a first time duration between the UE receiving the CSC and transmitting the ACK; and

transmitting (1606) , to the UE, a message including beam-related information during the first time interval or a second time interval corresponding to a second time duration between a transmission of the ACK and receiving an indication that the UE has completed the LLCM procedure, the message being formatted depending on whether the transmitting occurs during the first time interval or during the second time interval to facilitate UE’s interpretation of the beam-related information being related to the source cell or to the target cell.
The method of claim 14, further comprising:

receiving, from the UE, an indication the UE is able to perform the LLCMP; and

transmitting, to the UE, a radio resource control message configuring the one or more candidate cells.
The method of any of claims 14-15, the method further comprising:

limiting a number of LLCMP-related control message candidates transmitted in a slot or in a span during the second time interval to a predefined threshold.
An apparatus for wireless communication comprising a memory, communication hardware and a processor coupled to the memory and controlling the communication hardware, the apparatus being configured to implement a method as in any of claims 1-16.