Management of Timing Alignment with Multiple Receivers in a Wireless Communication System

Abstract

To manage synchronization, the user equipment receives (606) from the radio access network (RAN) a configuration including a first timing advance (TA) value and a second TA value, operates (608) a first TA timer (TAT) corresponding to the first TA value to manage synchronization between a first uplink (UL) transmission and a first receiver in the RAN, operates (610) a second TAT corresponding to the second TA value to manage synchronization between a second UL transmission and a second UL receiver in the RAN, stops (612) the first UL transmission in response to expiration of the first TAT, and stops (614) the second UL transmission in response to expiration of the second TAT.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority to U.S. Provisional Patent Application No. 63 / 393,818, entitled "MAINTAINING A TA VALUE IN A MULTIPLE - TRP SCENARIO IN A WIRELESS COMMUNICATION SYSTEM", filed on Jul. 29, 2022, and U.S. Provisional Patent Application No. 63 / 393,591, entitled "MANAGING MULTIPLE TIMING ADVANCE VALUES FOR MULTIPLE TRANSMIT AND / OR RECEIVE POINTS", filed on Jul. 29, 2022. The entire contents of those provisional applications are hereby expressly incorporated by reference herein.

[0002] The present disclosure generally relates to wireless communication, and more specifically, to maintaining a TA value in a serving cell on the UE side or the NW / base station (BS) side, and / or supporting the update and expiration of a Time Alignment Timer (TAT). This technology can be applied to scenarios with multiple transmit and / or receive points (M - TRP).

Background Art

[0003] This description of the background art is provided for the purpose of generally indicating the background of the present disclosure. The work of the inventors specified herein is not admitted as prior art to the present disclosure, either expressly or implicitly, to the extent described in this background art section and in aspects of the description that may not be eligible as prior art at the time of filing.

[0004] Generally speaking, a base station that operates a cellular radio access network (RAN) communicates with user equipment (UE) using a specific radio access technology (RAT) and multiple layers of a protocol stack. For example, the physical layer (PHY) of the RAT provides transport channels to the media access control (MAC) sublayer, which in turn provides logical channels to the radio link control (RLC) sublayer, which in turn provides a data transfer service to the packet data convergence protocol (PDCP) sublayer. The radio resource control (RRC) sublayer is positioned on top of the PDCP sublayer.

[0005] The RRC sublayer designates an RRC_IDLE state in which the UE does not have an active radio connection with the base station, an RRC_CONNECTED state in which the UE has an active radio connection with the base station, and an RRC_INACTIVE state that enables the UE to more quickly transition back and forth between the RRC_CONNECTED state using radio access network (RAN) level base station coordination and RAN level paging procedures. In some cases, a UE in the RRC_IDLE or RRC_INACTIVE state has only a relatively small single packet to transmit. In some such cases, a UE in the RRC_IDLE or RRC_INACTIVE state performs early data transmission without transitioning to the RRC_CONNECTED state.

[0006] Regarding the PHY layer, in some cases, different channel or reference signal (RS) configurations correspond to different beam indication techniques. Most DL transmissions (e.g., Physical Downlink Shared Channel (PDSCH), Physical Downlink Control Channel (PDCCH), or Channel State Information (CSI) Resource Signal (CSI-RS)), Transmission Configuration Indication (TCI) framework, and TCI states are applicable to such transmissions and are configured for that purpose. However, in some cases, PDCCH transmissions require a MAC-CE to further indicate the TCI state within the configured TCI state, and PDSCH transmissions similarly require a MAC-CE and Downlink Control Information (DCI) for that purpose. For the Physical Uplink Shared Channel (PUSCH), UL beam indication depends on the index of the sounding reference signal (SRS) resource transmitted by the UE at least once. In some embodiments, in the case of the Physical Uplink Control Channel (PUCCH), the MAC-CE indicates the spatial relationship for the UE to derive the UL beam. In further embodiments, the spatial relationship is also configured for the SRS resource set, which indicates the same UL beam applicable to all SRS resources within the SRS resource set. However, when many channels or RSs share the same beam, these messages may also require a large amount of signaling overhead. Summary of the Invention

[0007] Exemplary embodiments of the technology of the present disclosure are methods for managing synchronization. The method is implemented in a user equipment (UE) and includes receiving, from a radio access network (RAN), a configuration including a first timing advance (TA) value and a second TA value; operating a first TA timer (TAT) corresponding to the first TA value to manage synchronization between a first uplink (UL) transmission and a first receiver in the RAN; operating a second TAT corresponding to the second TA value to manage synchronization between a second UL transmission and a second receiver in the RAN; stopping the first UL transmission in response to expiration of the first TAT; and stopping the second UL transmission in response to expiration of the second TAT.

[0008] Another exemplary embodiment of these technologies is a user equipment (UE) comprising a transceiver and processing hardware configured to implement the above method.

Brief Description of the Drawings

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[0010] The techniques described below can be applied to an M-TRP scenario that includes multiple timing advance (TA) values, and the UE maintains multiple TA values in at least one serving cell. The techniques described below enable the UE and / or the base station to maintain TA alignment in an M-TRP scenario. These techniques also enable the UE to indicate / update TA values for various TA operation frameworks (s). These techniques can be applied to LTE, NR, or any other suitable RAT.

[0011] Referring first to FIG. 1A, an exemplary wireless communication system 100 includes a UE 102, a base station (BS) 104, a base station 106, and a core network (CN) 110. Base stations 104 and 106 can operate within a RAN 105 connected to a core network (CN) 110. CN 110 can be implemented, for example, as an evolved packet core (EPC) 111 or a fifth generation (5G) core (5GC) 160. CN 110 can also be implemented as a sixth generation (6G) core in another example.

[0012] The base station 104 can cover one or more cells (e.g., cells 124 and 125) with one or more transmit and / or receive points (TRPs). Similarly, the base station 106 can cover one or more cells (e.g., cell 126) with one or more TRPs. For example, the base station 104 operates cell 124 with TRPs 107-1 and 107-2, and operates cell 125 with TRP 107-3. The base station 106 operates cell 126 with TRPs 108-1 and 108-2. Cells 124 and 125 operate at the same carrier frequency. Cell 126 can be operated at the same carrier frequency as cells 124 and 125. Alternatively, cell 126 can be operated at a carrier frequency different from that of cells 124 and 125. In some embodiments, the base station 104 connects each of TRPs 107-1, 107-2, and 107-3 via a fiber connection or an Ethernet connection. If the base station 104 is a gNB, cells 124 and 125 are NR cells. If the base station 104 is an (ng)-eNB, cells 124 and 125 are evolved universal terrestrial radio access (EUTRA) cells. Similarly, if the base station 106 is a gNB, cell 126 is an NR cell, and if the base station 106 is an (ng)-eNB, cell 126 is an EUTRA cell. Cells 124, 125, and 126 can be within the same radio access network notification area (RNA) or different RNAs. In general, RAN 105 can include any number of base stations, and each of the base stations can cover one, two, three, or any other appropriate number of cells. The UE 102 can support at least one 5G NR (or simply "NR") or E-UTRA air interface to communicate with the base station 104 via TRP 107-1, TRP 107-2, and / or TRP-3. Similarly, the UE 102 can support at least one 5G NR (or simply "NR") or E-UTRA air interface to communicate with the base station 106 via TRP 108-1 and / or TRP 108-2. Each of the base stations 104 and 106 can be connected to the CN 110 via an interface (e.g., an S1 or NG interface).Base stations 104 and 106 can also be interconnected via an interface (e.g., X2 or Xn interface) for interconnecting NG RAN nodes.

[0013] When a base station (e.g., base station 104 or 106) transmits DL data via a TRP (e.g., TRP107-1, TRP107-2, TRP107-3, TRP108-1 or TRP108-2), base station 104 can generate a packet containing the data and send the packet to TRP107-1. For example, the packet can be a fronthaul transport protocol data unit. The TRP extracts the data from the packet and transmits the data. In some embodiments, base station 104 can include control information for time-critical control and management information directly related to the data in the packet, and the TRP can transmit the data according to the control information. In some embodiments, the data includes in-phase and quadrature (IQ) data, a physical layer bit sequence, or a MAC PDU. When the TRP receives data from a UE (e.g., UE102), the TRP generates a packet containing the data and sends the packet to base station 104. In some embodiments, the data includes IQ data, a physical layer bit sequence, or a MAC PDU.

[0014] Among other components, EPC 111 can include a Serving Gateway (SGW) 112, a Mobility Management Entity (MME) 114, and a Packet Data Network Gateway (PGW) 116. The SGW 112 is generally configured to transfer user plane packets related to, for example, voice calls, video calls, Internet traffic, etc. The MME 114 is configured to manage authentication, registration, paging, and other related functions. The PGW 116 provides a connection from the UE 102 to one or more external packet data networks (e.g., the Internet network and / or the Internet Protocol (IP) Multimedia Subsystem (IMS) network). The 5GC 160 includes a User Plane Function (UPF) 162, as well as an Access and Mobility Management Function (AMF) 164, and / or a Session Management Function (SMF) 166. Generally, the UPF 162 is configured to transfer user plane packets related to, for example, voice calls, video calls, Internet traffic, etc. The AMF 164 is configured to manage authentication, registration, paging, and other related functions. The SMF 166 is configured to manage PDU sessions.

[0015] As shown in FIG. 1A, base station 104 supports cells 124 and 125, and base station 106 supports cell 126. Cells 124, 125, and 126 can partially overlap, whereby the UE 102 can select from, reselect, or handover between one of cells 124, 125, and 126. To directly exchange messages or information, base station 104 and base station 106 can support an X2 or Xn interface. Generally, the CN 110 can connect to any suitable number of base stations that support NR cells and / or EUTRA cells.

[0016] The base station 104 includes processing hardware 130, which can include one or more general-purpose processors (e.g., CPUs) and a non-transitory computer-readable memory storing instructions executed by the one or more general-purpose processors. Additionally, or alternatively, the processing hardware 130 can include special-purpose processing units. The processing hardware 130 can include a PHY controller 132 configured to transmit data and control signals on a physical DL channel and DL reference signals to one or more user devices (e.g., UE 102) via one or more TRPs (e.g., TRP 107-1, TRP 107-2, and / or TRP 107-3). The PHY controller 132 is also configured to receive data and control signals on a physical UL channel and / or UL reference signals from one or more user devices via one or more TRPs (e.g., TRP 107-1, TRP 107-2, and / or TRP 107-3). The processing hardware 130 in an exemplary embodiment can include a MAC controller 134 configured to perform random access (RA) procedures with one or more user devices, manage UL timing advance for one or more user devices, receive UL MAC PDUs from one or more user devices, and transmit DL MAC PDUs to one or more user devices. The processing hardware 130 can further include an RRC controller 136 to implement procedures and messaging in the RRC sublayer of the protocol communication stack. The base station 106 can include processing hardware 140 similar to the processing hardware 130. In particular, components 142, 144, and 146 can be similar to components 132, 134, and 136, respectively.

[0017] UE 102 includes processing hardware 150, which can include one or more general-purpose processors such as a CPU, a non-transitory computer-readable memory storing machine-readable instructions executable by the one or more general-purpose processors, and / or a special-purpose processing unit. The PHY controller 152 is also configured to receive data and control signals and / or DL reference signals on the physical DL channel at the base station 104 or 106 via one or more TRPs (e.g., TRP 107-1, TRP 107-2, TRP 107-3, TRP 108-1, and / or TRP 108-2). The PHY controller 152 is also configured to transmit data and control signals and / or UL reference signals on the physical UL channel at the base station 104 or 106 via one or more TRPs (e.g., TRP 107-1, TRP 107-2, TRP 107-3, TRP 108-1, and / or TRP 108-2). The processing hardware 150 in an exemplary embodiment includes a MAC controller 154 configured to perform random access procedures at the base station 104 or 106, manage UL timing advance for one or more user devices, transmit UL MAC PDUs to the base station 104 or 106, and receive DL MAC PDUs from the base station 104 or 106. The processing hardware 150 can further include an RRC controller 156 to implement procedures and messaging in the RRC sublayer of the protocol communication stack.

[0018] Figure 1B shows an exemplary distributed or centralized implementation of one or both of base stations 104, 106. In this implementation, each of base stations 104 and / or 106 includes a Central Unit (CU) 172 and one or more Distributed Units (DUs) 174. CU 172 includes processing hardware such as one or more general-purpose processors (e.g., CPUs), a computer-readable memory storing machine-readable instructions executable on the general-purpose processor(s), and / or a special-purpose processing unit. For example, CU 172 can include a PDCP controller (e.g., PDCP controllers 134, 144), an RRC controller (e.g., RRC controllers 136, 146), and / or an RRC inactive controller (e.g., RRC inactive controllers 138, 148). In some implementations, CU 172 can include an RLC controller configured to manage or control one or more RLC operations or procedures. In other implementations, CU 172 does not include an RLC controller.

[0019] Each of DUs 174 also includes processing hardware that can include one or more general-purpose processors (e.g., CPUs), a computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors, and / or a special-purpose processing unit. For example, the processing hardware can include a MAC controller (e.g., MAC controllers 132, 142) configured to manage or control one or more MAC operations or procedures (e.g., random access procedures), and / or an RLC controller configured to manage or control one or more RLC operations or procedures. The processing hardware can also include a physical layer controller configured to manage or control one or more physical layer operations or procedures.

[0020] In some implementations, RAN 105 supports an Integrated Access Backhaul (IAB) function. In some implementations, DU 174 operates as an (IAB) node and CU 172 operates as an IAB donor.

[0021] In some embodiments, CU172 can include a logical node CU-CP172A that hosts the control plane portion of the PDCP protocol of CU172. CU172 can also include one or more logical nodes CU-UP172B that host the user plane portion of the PDCP protocol and / or the SDAP protocol of CU172. CU-CP172A can transmit control information (e.g., RRC messages, F1 application protocol messages), and CU-UP172B can transmit data packets (e.g., SDAP PDUs or IP packets).

[0022] CU-CP172A can be connected to a plurality of CU-UP172B via an E1 interface. CU-CP172A selects an appropriate CU-UP172B for the service requested by UE102. In some embodiments, a single CU-UP172B can be connected to a plurality of CU-CP172A via an E1 interface. When CU-CP172A and DU(s) 174 belong to a gNB, CU-CP172A can be connected to one or more DU174 via an F1-C interface and / or an F1-U interface. When CU-CP172A and DU(s) 174 belong to an ng-eNB, CU-CP172A can be connected to DU(s) 174 via a W1-C interface and / or a W1-U interface. In some embodiments, one DU174 can be connected to a plurality of CU-UP172B under the control of the same CU-CP172A. In such embodiments, the connectivity between CU-UP172B and DU174 is established by CU-CP172A using a bearer context management function.

[0023] FIG. 2A shows a simplified exemplary protocol stack 200, according to which UE102 can communicate with an eNB / ng-eNB or a gNB (e.g., one or both of base stations 104, 106).

[0024] In the exemplary stack 200, the physical layer (PHY) 202A of EUTRA provides transport channels to the EUTRA MAC sublayer 204A, and the EUTRA MAC sublayer 204A then provides logical channels to the EUTRA RLC sublayer 206A. The EUTRA RLC sublayer 206A then provides RLC channels to the EUTRA PDCP sublayer 208 and, optionally, to the NR PDCP sublayer 210. Similarly, the NR PHY 202B provides transport channels to the NR MAC sublayer 204B, and the NR MAC sublayer 204B then provides logical channels to the NR RLC sublayer 206B. The NR RLC sublayer 206B then provides a data transfer service to the NR PDCP sublayer 210. The NR PDCP sublayer 210 can then provide a data transfer service to the SDAP sublayer 212 or an RRC sublayer (not shown in FIG. 2A). The UE 102, in some embodiments, supports both the EUTRA and NR stacks as shown in FIG. 2A, supports handover between the EUTRA base station and the NR base station, and / or supports dual connectivity (DC) via the EUTRA interface and the NR interface. Further, as shown in FIG. 2A, the UE 102 can support the layering of NR PDCP 210 on EUTRA RLC 206A and the SDAP sublayer 212 on the NR PDCP sublayer 210.

[0025] The EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 receive packets, which may be referred to as service data units (SDUs) (e.g., from an IP layer directly or indirectly layered on the PDCP layer 208 or 210), and output packets, which may be referred to as protocol data units (PDUs) (e.g., to the RLC layer 206A or 206B). Except where the difference between an SDU and a PDU is relevant, in the present disclosure, for simplicity, both SDUs and PDUs are referred to as "packets".

[0026] In the control plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 provide signaling radio bearers (SRBs) to the RRC sublayer (not shown in FIG. 2A) and can exchange, for example, RRC messages or NAS messages. In the user plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 provide data radio bearers (DRBs) and can support data exchange. The data exchanged in the NR PDCP sublayer 210 can be an SDAP PDU, an IP packet, or an Ethernet packet.

[0027] Therefore, the radio protocol stack can be functionally split as shown by the radio protocol stack 250 in FIG. 2B. The CU in one or both of the base stations 104, 106 can hold all control and upper layer functions (e.g., RRC 214, SDAP 212, NR PDCP 210), while the lower layer operations (e.g., NR RLC 206B, NR MAC 204B, and NR PHY 202B) are delegated to the DU. To support the connection to the 5GC, the NR PDCP 210 provides an SRB to the RRC 214, the NR PDCP 210 provides a DRB to the SDAP 212, and provides an SRB to the RRC 214.

[0028] FIG. 3A shows the detailed structure 300A of the NR layer 2 protocol stack 200 or 250 of base station being shown in FIG. 3A) provides transport channels to MAC sublayer 204. The MAC sublayer 204 includes scheduling and / or prioritization handling functions for scheduling and / or prioritizing DL and UL transmissions with one or more user devices. The MAC sublayer 204 also includes a multiplexing function for DL transmissions with a specific user device and / or a demultiplexing function for UL transmissions. The MAC sublayer 204 further includes a hybrid automatic repeat request (HARQ) entity for each DL transmission and / or UL transmission on a specific DL component carrier (CC) and / or a specific UL CC with a specific user device. The RLC sublayer 206 includes segmentation and automatic repeat request (ARQ) functions for DL data and UL data communicating with one or more UEs. The PDCP sublayer 210 provides radio bearers to the SDAP sublayer 212 and includes (i) security and (ii) robust header compression (ROHC) functions for (i) integrity protection and / or encryption / decryption, and (ii) header compression / decompression, respectively. The SDAP sublayer 212 provides 5GC QoS flows to upper layer(s).

[0029] FIG. 3B shows a detailed structure 300B of an NR layer 2 protocol stack 200 or 250 for UE102, similar to structure 300A. PHY202 (not shown in FIG. 3B) provides transport channels for DL and UL transmissions to / from base station(s) 104 or 106 to the MAC sublayer 204. The MAC sublayer 204 includes one or more HARQ entities for DL transmission and / or UL transmission on a specific DL CC and / or a specific UL CC to / from base station(s) 104 or 106, respectively. The MAC sublayer 204 also includes a logical channel prioritization and multiplexing function for UL transmission to base station(s) 104 or 106 and a demultiplexing function for DL transmission from base station(s) 104 or 106. The RLC sublayer 206 includes a segmentation and automatic repeat request (ARQ) function for DL data and UL data communicating with base station(s) 104 and / or 106. The PDCP sublayer 210 provides radio bearers to the SDAP sublayer 212 and includes (i) security and (ii) robust header compression (ROHC) functions for (i) integrity protection and / or encryption / decryption, and (ii) header compression / decompression, respectively. The SDAP sublayer 212 provides 5GC QoS flows to upper layer(s).

[0030] FIGS. 4A - 4C show different embodiments of HARQ entities for multi - TRP (mTRP) operation on a specific CCy (e.g., UL CC or DL CC), which can be implemented in UE102, base station 104 or 106, or DU174 of base station 104 or 106.

[0031] Referring first to FIG. 4A which shows a HARQ entity 400A. In some embodiments, the HARQ entity 400A includes HARQ processes 1, …, N for communicating with TPR1…,m. N is an integer greater than zero and m is an integer greater than zero. For example, N can be 8, 16, 32, etc. and m can be 2, 3, 4, etc.

[0032] Next, FIG. 4B shows a further embodiment of the HARQ entity 400B, which is similar to the HARQ entity 400A. The difference between the embodiments of the HARQ entities 400B and 400A is that the HARQ entity 400B divides the HARQ processes 1, …, N into m groups, each of which is used for communication with a specific TRP.

[0033] Next, FIG. 4C shows an embodiment of the HARQ entity 400C (e.g., HARQ entity k), similar to the HARQ entity 400A. The difference between the embodiments of the HARQ entities 400C and 400A is that the HARQ entity 400C is used for communication with a specific TRP (e.g., TRP k ) on a specific CC (e.g., CCk, where 1 ≤ k ≤ m). In other words, the UE 102 uses the HARQ entities 1, …, m to communicate with the RAN node (e.g., base station 104 or 106, or DU 174) via the TRPs 1, …, m on each UL CC, respectively. Similarly, the RAN node uses the HARQ entities 1, …, m to communicate with the UE 102 via the TRPs 1, …, m of the RAN node (e.g., base station 104 or 106, or DU 174) on each DL CC, respectively.

[0034] Next, several exemplary scenarios related to mTRP operation, including the various components of FIG. 1A, will be described with reference to FIGS. 5A to 5E. Generally, the events in FIGS. 5A to 5E that may be the same are labeled with the same reference numerals.

[0035] Referring initially to FIG. 5A, in scenario 500A, base station 104 operates cell 124, TRP 107-1, and TRP 107-2. In scenario 500A, base station 104 broadcasts (504, 506) one or more synchronization signal blocks (SSBs) 508, 510 and system information via TRP 107-1 (e.g., periodically). In some embodiments, the system information includes a master information block (MIB) and / or a system information block (SIB). In some examples, the SIB includes SIB1 and further includes SIB2, SIB3, SIB4, and / or SIB5. UE 102 initially operates in an idle state (e.g., RRC_IDLE state) (502). The idle state UE 102 receives SSBs from base station 104 via TRP 107-1 (504, 506) and receives system information (508, 510). In some embodiments, UE 102 detects that base station 104 transmits an SSB via TRP 107-1. In some embodiments, UE 102 then uses one of the SSBs to perform downlink synchronization with base station 104 on cell 124 via TRP 107-1 and receives system information via TRP 107-1 based on the SSB (508, 510).

[0036] Subsequently, UE102 decides to execute a random access procedure (590) and then execute an RRC connection establishment procedure (592). In response to the decision, UE102 transmits a first random access preamble 512 on a time / frequency resource and / or a random access occasion of the random access channel (RACH) to TRP107-1. Then TRP107-1 forwards the first random access preamble to base station 104 (514). In some embodiments, UE102 selects an SSB from SSBs where the RSRP acquired by UE102 exceeds a first threshold of the random access procedure (e.g., rsrp-ThresholdSSB). In other embodiments, if the RSRP of any SSB within the SSB does not exceed the first threshold, UE102 selects an SSB from the SSBs and uses that SSB to determine the first random access preamble. In some such cases, UE102 selects an SSB from the SSBs randomly or based on the UE implementation. UE102 then determines the first random access preamble, time / frequency resource, and / or RACH occasion based on the selected SSB and the random access configuration parameters included in the system information (e.g., SIB1). In some embodiments, the random access configuration parameters indicate one or more associations between (i) the SSB and (ii) the random access preamble, the RACH occasion, and / or the time / frequency resource. Based on the selected SSB and the association, UE102 determines the first random access preamble, the RACH occasion, and / or the time / frequency resource for transmitting the first random access preamble.

[0037] In response to the first random access preamble, the base station 104 transmits a first random access response to TRP107-1 (516). Next, TRP107-1 forwards the first random access response to UE102 (518). In some embodiments, the base station 104 or TRP107-1 identifies the SSB associated with the first random access preamble, RACH occasion, and / or time / frequency resource. In the case where a single SSB is associated with the first random access preamble, RACH occasion, and / or time / frequency resource, the identified SSB is the SSB selected by UE102. In the case where multiple SSBs are associated with the first random access preamble, RACH occasion, and / or time / frequency resource, the identified SSB is the same as or different from the SSB selected by UE102. In such embodiments, the base station 104 transmits the first random access response to UE102 via TRP107-1 based on the identified SSB. The base station 104 includes a first preamble ID and a first TA command in the first random access response. The first preamble ID identifies the first random access preamble, and the first TA command includes a first TA value. The UE applies the first TA value and, after applying the first TA value (e.g., in response thereto), determines or maintains an uplink synchronized (e.g., time-aligned) with TRP107-1 (520). UE102 applies the first TA value to transmit UL transmissions (e.g., PUCCH transmissions, PUSCH transmissions, and / or sounding reference signal transmissions) until it receives a new or different TA value from the base station 104 to update the first TA value. In some embodiments, UE102 starts a first time alignment timer (TAT) to maintain the UL synchronization status with TRP107-1 or the base station 104 after or when receiving the first TA command. In some embodiments, the base station 104 includes a UL grant (i.e., an RAR grant) in the random access response.

[0038] In some embodiments, after the base station 104 transmits a random access response or a first TA command to the UE 102, it starts a first TAT to maintain a first UL synchronization for UL and / or DL communication with the UE 102 via the TRP 107-1. In some embodiments, the TRP 107-1 generates timing information based on the timing information of the first random access preamble received from the UE 102, or the timing information based on the first random access preamble received from the UE 102, and transmits the timing information to the base station 104. In some examples, the timing information indicates a propagation delay or a propagation delay shift. Based on the timing information received from the TRP 107-1, the base station 104 determines a first TA value.

[0039] Blocks 512, 514, 516, 518, and 520 are collectively referred to as a random access procedure 590 in FIG. 5A.

[0040] During or after the random access procedure 590, the UE 102 transmits an RRC setup request message (e.g., RRC Setup Request message) to the base station via the TRP 107-1 (522, 524). In some embodiments, the UE 102 uses the UL grant received in the random access response to transmit the RRC setup request message. In response to the RRC setup request message, the base station 104 transmits an RRC setup message (e.g., RRC Setup message) to the UE 102 via the TRP 107-1 (526, 528). In some embodiments, the base station 104 transmits a MAC PDU including contention resolution (e.g., MAC control element (CE)) to the UE 102 to resolve the contention of the random access procedure. In some embodiments, the base station 104 includes the RRC setup message in the MAC PDU. In a further embodiment, after transmitting the MAC PDU, the base station 104 transmits another MAC PDU including the RRC setup message to the UE 102. In response to the RRC setup message, the UE 102 transitions to the connected state (e.g., RRC_CONNECTED) (530) and transmits an RRC setup complete message (e.g., RRC Setup complete message) to the base station 104 via the TRP 107-1 (532, 534). In some embodiments, after performing the RRC connection establishment procedure with the UE 102, the base station 104 performs a security activation procedure at the UE 102 and activates security protection (e.g., integrity protection / integrity check and encryption / decryption) for the UL data and DL data communicated between the UE 102 and the base station 104. In a further embodiment, after performing the RRC connection establishment procedure or the security activation procedure, the base station 104 performs a radio bearer configuration procedure with the UE 102 to configure the SRB2 and / or DRB of the UE 102.

[0041] After performing the RRC connection establishment procedure, the security activation procedure, or the radio bearer configuration procedure, the base station 104 transmits an RRC reconfiguration message (e.g., an RRCReconfigration message) including a channel state information (CSI) resource configuration and a CSI report configuration to the UE 102 via the TRP107-1 (536, 538). In response, the UE 102 transmits an RRC reconfiguration complete message (e.g., an RRCReconfigurationComplete message) to the base station 104 via the TRP107-1 (540, 542). In some embodiments, the CSI resource configuration includes configuration parameters for configuring a channel state information reference signal (CSI-RS) that the UE 102 measures. The base station 104 transmits the CSI-RS via the TRP107-2 according to the CSI resource configuration. The UE 102 performs measurements with the CSI-RS according to the CSI resource configuration. In some embodiments, the CSI resource configuration includes configuration parameters for configuring an SSB for the UE 102 to measure. The base station 104 transmits the SSB via the TRP107-2. The UE 102 performs measurements with the SSB according to the CSI resource configuration. In other embodiments, the RRC reconfiguration message or the CSI resource configuration does not include configuration parameters for configuring the SSB. In some such cases, the base station 104 still transmits the SSB via the TRP107-2, and the UE 102 performs measurements on the SSB. Based on the CSI report configuration, the UE 102 generates a CSI report from the measurement values of the CSI-RS or the SSB and transmits the CSI report to the base station 104 via the TRP107-1 (544, 546). In some embodiments, the UE 102 transmits the CSI report on the PUCCH to the base station 104 via the TRP107-1. In some embodiments, the CSI report configuration configures a periodic or semi-persistent report, or the CSI report configuration configures a semi-persistent or aperiodic report triggered by DCI. The CSI report includes a periodic CSI report, a semi-persistent CSI report, and / or an aperiodic CSI report.

[0042] In some embodiments, the base station 104 includes a CSI resource configuration and / or a CSI report configuration in a CSI measurement configuration (e.g., CSI-MeasConfigIE). The base station 104 then includes the CSI measurement configuration in the RRC reconfiguration messages for events 536, 538. In other embodiments, the CSI resource configuration includes NZP-CSI-RS-ResourceIE, NZP-CSI-RS-ResourceSetIE, CSI-SSB-ResourceSetIE, CSI-ResourceConfigIE, and / or CSI-ReportConfigIE.

[0043] Blocks 536, 538, 540, 542, 544, and 546 are collectively referred to as CSI resource configuration and CSI reporting procedure 594 in FIG. 5A.

[0044] After receiving a CSI report in event 546, the base station 104 determines to communicate with the UE 102 via the TRP 107-2 based on the CSI report while maintaining the link with the UE 102 via the TRP 107-1. In some embodiments, the base station 104 makes the determination based on the capabilities of one or more UEs 102. In response to the determination, the base station 104 transmits (548, 550) an RRC reconfiguration message including DL and UL configuration parameters for DL and UL communication between the base station 104 and the UE 102 via the TRP 107-2 to the UE 102 via the TRP 107-1. In some embodiments, the base station 104 includes the DL and UL configuration parameters in a CellGroupConigIE and includes the CellGroupConfigIE in the RRC reconfiguration message. In some embodiments, the base station 104 includes DL configuration parameters such as BWP-DownlinkDedicatedIE in a bandwidth part (BW) IE and includes the BWP-DownlinkDedicatedIE in the RRC reconfiguration message. In some embodiments, the base station 104 includes UL configuration parameters in a BWP-UplinkDedicatedIE and includes the BWP-UplinkDedicatedIE in the RRC reconfiguration message.

[0045] In response to the RRC reconfiguration complete message, UE 102 transmits the RRC reconfiguration complete message to base station 104 via TRP 107-1 (552, 554). In some embodiments, when UE 102 receives an RRC reconfiguration message in event 554, it applies the DL configuration parameters. In such embodiments, UE 102 performs DL communication with base station 104 via TRP 107-2 according to the DL configuration parameters while performing DL and UL communication with base station 104 via TRP 107-1 (556). In some embodiments, UE 102 refrains from performing UL communication according to the UL configuration parameters until after performing a random access procedure with base station 104 via TRP 107-2 in event 598. In further embodiments, UE 102 refrains from performing DL communication with base station 104 via TRP 107-2 until after performing a random access procedure with base station 104 via TRP 107-2 in event 598. In some embodiments, base station 104 refrains from performing UL communication and / or configuring UL configuration parameters until after completing a random access procedure with base station 104 via TRP 107-2 in event 598. In some embodiments, base station 104 refrains from performing DL communication and / or configuring DL configuration parameters until after completing a random access procedure with base station 104 via TRP 107-2 in event 598.

[0046] In some embodiments, base station 104 and UE 102 use the HARQ entity of FIG. 4A, FIG. 4B, or FIG. 4C to perform DL communication with base station 104 via TRP 107-1 and TRP 107-2 at event 556. In the case of the HARQ entity 400B of FIG. 4B, for example, the DL configuration parameters of events 548, 550 include HARQ configuration parameters. The HARQ configuration parameters constitute a first set of HARQ process IDs and a second set of HARQ process IDs. In some cases, the first set of HARQ process IDs and the second set of HARQ process IDs are for TRP 107-1 and TRP 107-2, respectively. The first set of HARQ process IDs and the second set of HARQ process IDs identify a first set of HARQ processes of the HARQ entity and a second set of HARQ processes of the HARQ entity, respectively. In some embodiments, neither the first set of HARQ process IDs nor the second set of HARQ process IDs are the same. In other embodiments, some of the first set of HARQ process IDs and the second set of HARQ process IDs are the same and the others are different.

[0047] In some embodiments, the base station 104 transmits one or more MAC control elements (CEs) or DCI to the UE 102 and changes or updates one or more HARQ process IDs within a first set of HARQ process IDs. In some embodiments, the base station 104 transmits one or more MAC CEs or DCI to the UE 102 and changes or updates one or more HARQ process IDs within a second set of HARQ process IDs. In some alternative embodiments, the base station 104 does not configure a first set of HARQ process IDs and a second set of HARQ process IDs within the DL configuration parameters. In some embodiments, the base station 104 determines a first set of HARQ process IDs and a second set of HARQ process IDs for mTRP operation based on pre-configuration. In further embodiments, the first set of HARQ process IDs and the second set of HARQ process IDs are specific predetermined IDs (such as defined in the 3GPP (registered trademark) specifications). In further embodiments, the base station 104 determines the first set of HARQ process IDs and the second set of HARQ process IDs based on rules.

[0048] In some embodiments, when the base station 104 determines to schedule the UE 102 to receive the DL transmission to the TRP 107-1, the base station 104 selects a HARQ process ID from a first set of HARQ process IDs, and transmits to the UE 102 a DCI including a DL allocation and the selected HARQ process ID. The UE 102 uses the HARQ process identified by the selected HARQ process ID and uses the HARQ process and the UL grant to receive the DL transmission from the base station 104. Similarly, when the base station 104 determines to schedule the UE 102 to transmit the UL transmission to the TRP 107-2, the base station 104 selects a HARQ process ID from a second set of HARQ process IDs, and transmits to the UE 102 a DCI including a UL grant and the selected HARQ process ID. The UE 102 uses the HARQ process identified by the selected HARQ process ID and uses the HARQ process and the DL grant to receive the DL transmission from the base station 104.

[0049] In some embodiments, one or more capabilities include at least one capability indicating that the UE 102 supports mTRP operation (e.g., Release 16 capability fields / IEs and / or Release 17 capability fields / IEs in 3GPP specification 38.306 or 38.331 v17.1.0 or later versions for mTRP operation). In some embodiments, the base station 104 determines to configure DL configuration parameters for DL communication with the base station 104 via the TRP 107-2 based on at least one first capability. In some embodiments, the base station 104 determines UL configuration parameters for UL communication with the base station 104 via the TRP 107-2 based on at least one first capability. In the case where the base station 104 includes the DU 174 and the CU 172, the DU 174 makes the determination.

[0050] In some implementations, one or more capabilities include at least one second capability. In some such embodiments, the at least one second capability indicates that UE102 supports multiple UL transmission timings (i.e., two or more TAs) for mTRP operation with the serving cell. In a further embodiment, the at least one second capability indicates that UE102 supports multiple UL transmission timings (for mTRP operation) with the serving cell and non-serving cells. The physical cell index (PCI) of the non-serving cell is different from that of the serving cell. In some embodiments, the at least one second capability includes the number of UL transmission timings that UE102 supports with the serving cell and / or across all serving cells configured / activated for UE102 (for mTRP operation). In a further embodiment, the at least one second capability does not include the number of UL transmission timings (for mTRP operation), and indicates that UE102 supports the default number (e.g., two) of UL transmission timings. In some embodiments, base station 104 determines to configure UL configuration parameters for UL communication with base station 104 via TRP107-2 based on the at least one second capability. In the case where base station 104 includes DU174 and CU172, DU174 makes the determination.

[0051] In some embodiments, base station 104 receives one or more capabilities from UE102 after receiving an RRC setup complete message or after performing a security activation procedure with UE102. In some embodiments, base station 104 transmits a UE capability inquiry message (e.g., a UECapabilityEnquiry message) to UE102 and, in response, receives a UE capability information message (e.g., a UECapabilityinfo message) including one or more capabilities from the UE.

[0052] In other embodiments, the base station 104 receives a CN-to-BS message including one or more capabilities from the CN 110 (e.g., after receiving an RRC setup complete message). In some embodiments, the base station 104 transmits a BS-to-CN message to the CN 110 after receiving an RRC setup complete message, and the CN 110 transmits a CN-to-BS message (e.g., in response to the reception) after receiving the BS-to-CN message. In some embodiments, the UE 102 transmits a NAS message (e.g., a Registration Request message or a Registration Complete message) including a capability ID identifying one or more capabilities to the CN 110, and the CN 110 obtains one or more capabilities from the capability ID. In other embodiments, the UE 102 executes a registration procedure with the CN 110 via a base station (e.g., base station 104 or 106) prior to event 502 of registering with the CN 110. During the registration procedure, the UE 102 receives a UE capability enquiry message (e.g., a UECapabilityEnquiry message) from the base station and transmits a UE capability information message (e.g., a UECapabilityinfo message) including one or more capabilities to the base station. The base station transmits a BS-to-CN message including one or more capabilities to the CN 110, and the CN 110 stores one or more capabilities. In some embodiments, the CP-to-BS message and the BS-to-CN message are NG application protocol (NGAP) messages. In the case where the base station 104 includes the DU 174 and the CU 172, the CU 172 transmits a CU-to-DU message including one or more capabilities to the DU 174. In some embodiments, the message from the CU to the DU is an F1 application protocol (F1AP) message.

[0053] In some embodiments, the base station 104 can include random access configuration parameters in the RRC reconfiguration message for the UE 102 to perform a random access procedure (598). In some embodiments, the random access configuration parameters are dedicated to the UE 102. For example, the base station 104 generates a RACH configuration (e.g., RACH-ConfigDedicated, RACH-ConfigDedicated-r18, or RACH-ConfigDedicated-v1800IE) that includes random access configuration parameters dedicated to the UE 102. In some embodiments, the format of the RRCReconfiguration message includes a ReconfigurationWithSync IE, and the ReconfigurationWithSync IE includes a RACH-ConfigDedicatedIE (e.g., including a RACH configuration or random access configuration parameters) as defined (e.g., in 3GPP specification 38.331 v17.0.0 or later versions). In the case where the RRC reconfiguration message is a RRCReconfiguration message, the base station 104 includes in the RRCReconfiguration message a RACH configuration or random access configuration parameters for the RRCReconfiguration message, and these parameters do not include a ReconfigurationWithSync IE and do not wrap the RACH configuration or random access configuration parameters in the ReconfigurationWithSync IE. If the base station 104 includes random access configuration parameters using the ReconfigurationWithSync IE, the ReconfigurationWithSync IE causes the UE 102 to perform a handover, thereby interrupting the communication between the UE 102 and the base station 104. In other embodiments, the base station 104 refrains from including random access configuration parameters in the RRC reconfiguration message.

[0054] In some embodiments, the base station 104 indicates in the RRC reconfiguration message that UL synchronization is required (i.e., for communication with the base station 104 via the second TRP). That is, the base station 104 configures the UE 102 to acquire a (second) UL synchronization for communication between the UE 102 and the TRP 107-1 while maintaining a first UL synchronization for communication between the UE 102 and the TRP 107-2. In other words, the base station 104 configures the UE to maintain two TA values for communication between the UE 102 and the base station 104 (e.g., between the UE 102 and the TRP 107-1 and between the UE 102 and the TRP 107-2, respectively). In further embodiments, the base station 104 includes in the RRC reconfiguration message a configuration (e.g., a field or IE (e.g., an RRC Release 18 field or IE)) indicating that UL synchronization is required for communication between the UE 102 and the TRP 107-2. In other words, this configuration enables the operation of two TA values for communication between the UE 102 and the base station 104 (e.g., between the UE 102 and the TRP 107-1 and between the UE 102 and the TRP 107-2, respectively).

[0055] In some embodiments, in response to receiving a field or IE, the UE 102 starts a random access procedure (598) before transmitting a UL transmission (e.g., a channel state information (CSI) report, a sounding reference signal (SRS), a PUCCH transmission, and / or a PUSCH transmission) to the base station via the TRP 107-2. In some such embodiments, if the RRC reconfiguration message does not include a field or IE, the UE 102 does not start a random access procedure and transmits a UL transmission to the base station via the TRP 107-2. In further embodiments, the UE 102 refrains from transmitting a UL transmission to the base station via the TRP 107-2 in response to receiving a field or IE. In some such cases, the UE 102 does not transmit a random access preamble to the base station 104 via the TRP 107-2 until it receives a PDCCH order (e.g., events 558, 560, 559, 561) from the base station.

[0056] Blocks 548, 550, 552, 554, and 556 are collectively referred to as the TRP configuration procedure 596A in FIG. 5A.

[0057] In some embodiments, after receiving an RRC reconfiguration message at event 538, after performing CSI resource configuration and CSI reporting procedure 594, or after performing a TRP configuration procedure 596A with base station 104, UE 102 receives a RS from base station 104 via TRP 107-2 (562, 564). Depending on the embodiment, the RS is configured with the CSI resource configuration of event 538, and events 562, 564 occur during or after the CSI resource configuration and CSI reporting procedure 594, or during or after the TRP configuration procedure 596A, after receiving the RRC reconfiguration message at event 538. After performing the TRP configuration procedure 596A with base station 104, UE 102 starts a random access procedure (598). In response to starting the random access procedure, UE 102 transmits a second random access preamble in a time / frequency resource and a random access channel (RACH) occasion to base station 104 via TRP 107-2 (566, 568). In response to the second random access preamble, base station 104 transmits a second random access response to UE 102 via TRP 107-2 (570, 572). Base station 104 includes a second preamble ID and a second TA command in the second random access response. The second preamble ID identifies the second random access preamble, and the second TA command includes a second TA value. The UE applies the second TA value and, after applying the second TA value (e.g., in response thereto), determines or maintains an uplink synchronized with TRP 107-2 (574). UE 102 transmits UL transmissions (e.g., PUCCH transmissions, PUSCH transmissions, and / or SRS transmissions) applying the second TA value until UE 102 receives a new or different TA value from base station 104 to update the second TA value. In some embodiments, UE 102 starts a second TAT and maintains or manages the UL synchronization status with TRP 107-2 or base station 104 after or when receiving the second TA command.In some embodiments, the base station 104 includes a UL grant (e.g., an RAR grant) in the second random access response, and the UE 102 transmits a UL MAC PDU to the base station 104 via the TRP 107-2 according to the UL grant. In the case where the random access procedure is a contention-based random access procedure, the UE 102 includes the C-RNTI of the UE 102 in the UL MAC PDU. The base station 104 identifies the UE 102 based on the C-RNTI. In response to this identification, the base station 104 generates a DCI and a CRC of the DCI, scrambles the CRC with the C-RNTI, and transmits the DCI and the scrambled CRC to the UE 102 on a PDCCH. In some embodiments, the DCI includes an nUL grant. Upon receiving the DCI and the scrambled CRC on the PDCCH, the UE 102 determines that the content-based random access procedure 598 has been successfully executed. In the case where the random access procedure 598 is a contention-free random access procedure, the UE 102 determines that the content-based random access procedure 598 has been successfully executed in response to receiving a second random access response message.

[0058] In some embodiments, after the base station 104 starts a second TAT and transmits a second TA command to the UE 102 (e.g., in response thereto), the base station 104 maintains a second UL synchronization for UL and / or DL communication with the UE 102 via the TRP 107-2. In some embodiments, the TRP 107-1 generates timing information of a second random access preamble received from the UE 102 and transmits the timing information to the base station 104. As an example, the timing information indicates a propagation delay or a propagation delay shift. Based on the timing information received from the TRP 107-1, the base station 104 determines a second TA value.

[0059] Blocks 566, 568, 570, 572, and 574 are collectively referred to as the random access procedure 598 in FIG. 5A.

[0060] In some embodiments, while executing the random access procedure 598, UE 102 suspends communication with the base station 104 via TRP 107-1 (e.g., receiving DL channels / RSs or transmitting UL channels / RSs). Depending on the embodiment, if UE 102 cannot simultaneously execute the random access procedure based on the UL beam or RS (i.e., towards the TRP), and cannot communicate UL and DL transmissions (i.e., not related to the random access procedure) based on another UL beam or RS (i.e., towards another TRP), UE 102 suspends communication. In other embodiments, while executing the random access procedure 598, UE 102 continues communication with the base station 104 via TRP 107-2. After successfully completing the random access procedure (598), the UE executes DL and UL communication with the base station via TRP 107-1 and TRP 107-2 respectively according to the first TA value and the second TA value (576).

[0061] In some embodiments, the base station 104 and the UE 102 use a HARQ entity (such as shown in FIGS. 4A, 4B, or 4C) to perform UL communication with the base station 104 via the TRP 107-1 and the TRP 107-2 in event 576. In some cases (such as in the exemplary HARQ entity of FIG. 4B), the UL configuration parameters of events 548 and 550 include HARQ configuration parameters. The HARQ configuration parameters constitute a first set of HARQ process IDs and a second set of HARQ process IDs. In some cases, the first set of HARQ process IDs and the second set of HARQ process IDs are for the TRP 107-1 and the TRP 107-2, respectively. The first set of HARQ process IDs and the second set of HARQ process IDs identify a first set of HARQ processes of the HARQ entity and a second set of HARQ processes of the HARQ entity, respectively. In some embodiments, neither the first set of HARQ process IDs nor the second set of HARQ process IDs are the same. In other embodiments, some of the first set of HARQ process IDs and the second set of HARQ process IDs are the same and others are different.

[0062] In some embodiments, the base station 104 transmits one or more MAC CE or DCI to the UE 102 and changes or updates one or more HARQ process IDs within a first set of HARQ process IDs. In some further embodiments, the base station 104 transmits one or more MAC CE or DCI to the UE 102 and changes or updates one or more HARQ process IDs within a second set of HARQ process IDs. In some alternative embodiments, the base station 104 does not configure a first set of HARQ process IDs and a second set of HARQ process IDs within the UL configuration parameters. In some embodiments, the base station 104 determines a first set of HARQ process IDs and a second set of HARQ process IDs for mTRP operation based on a pre-configuration. In a further embodiment, the first set of HARQ process IDs and the second set of HARQ process IDs are a predefined set (such as defined in the 3GPP specifications). Further, in a further embodiment, the base station 104 determines a first set of HARQ process IDs and a second set of HARQ process IDs based on rules.

[0063] In some embodiments, when the base station 104 determines to schedule the UE 102 to receive UL transmissions to the TRP 107-1, the base station 104 selects a HARQ process ID from a first set of HARQ process IDs and transmits to the UE 102 a DCI including a UL grant and the selected HARQ process ID. The UE 102 uses the HARQ process identified by the selected HARQ process ID and uses the HARQ process and the UL grant to transmit a UL transmission to the base station 104. Similarly, when the base station 104 determines to schedule the UE 102 to transmit UL transmissions to the TRP 107-2, the base station 104 selects a HARQ process ID from a second set of HARQ process IDs and transmits to the UE 102 a DCI including a UL grant and the selected HARQ process ID. The UE 102 uses the HARQ process identified by the selected HARQ process ID and uses the HARQ process and the UL grant to transmit a UL transmission to the base station 104.

[0064] In some embodiments, after receiving the RRC reconfiguration complete message in event 554, the base station 104 transmits a PDCCH order to the UE 102 via the TRP 107-2 (558, 560) to cause the UE 102 to initiate a random access procedure 598 with the base station 104 via the TRP 107-2. In some embodiments, the PDCCH order includes an RS index and a random access preamble index. Alternatively, the base station 104 transmits a PDCCH order to the UE 102 via the TRP 107-1. In response to the PDCCH order, the UE 102 transmits a random access preamble to the base station 104 via the TRP 107-2 in event 566. In some embodiments, the random access preamble index includes a value of a second preamble ID that identifies the second random access preamble. Accordingly, the UE 102 determines the second random access preamble according to the random access preamble index. In other embodiments, the random access preamble index includes a value that indicates or instructs the UE 102 to determine the random access preamble. Accordingly, the UE 102 determines the second random access preamble by (randomly) selecting the second random access preamble from the random access preambles configured in the system information.

[0065] In some embodiments, the PDCCH order is DCI. The base station 104 generates the DCI and the CRC of the DCI, scrambles the CRC with the C-RNTI, and transmits the DCI and the scrambled CRC to the TRP 107-2 (e.g., via a fiber connection). Next, the TRP 107-2 transmits the DCI and the scrambled CRC to the UE 102 on the PDCCH. In some embodiments, the base station 104 transmits a first packet including the DCI and the scrambled CRC to the TRP 107-2. In some embodiments, the base station 104 transmits control information that configures or indicates the time resource and / or frequency resource of the PDCCH to the TRP ********. In some embodiments, the time resource and / or frequency resource includes subcarriers, resource elements, or physical resource blocks. The TRP 107-2 transmits the DCI and the scrambled CRC on the time resource and / or frequency resource according to the control information. In some embodiments, the base station 104 includes control information in the first packet. In other embodiments, the base station 104 transmits a second packet including control information to the TRP 107-2 instead of the first packet. In other embodiments, the base station 104 does not transmit the control information of the DCI and the scrambled CRC to the TRP 107-2. In such embodiments, the TRP 107-2 determines the time and / or frequency resource of the PDCCH and transmits the DCI and the scrambled CRC on the time and / or frequency resource.

[0066] It should be noted that there seems to be an incomplete number "107-2" in the original text where "********" is shown in the translation. Please check and correct if necessary.In some embodiments, the RS index (e.g., SSB index) identifies one of the SSBs. In some such embodiments, the base station 104 determines or decodes the SSB index indicated in the CSI report. In further embodiments, the base station 104 determines or decodes the SSB index based on a radio resource (e.g., PUCCH resource) on which the base station 104 receives one of the CSI reports for the SSB. In some such embodiments, the base station 104 configures different radio resources for the UE 102 and transmits a CSI report for each of the SSBs. In some examples, the base station 104 includes a configuration in the RRC reconfiguration message of event 536 to configure different radio resources (e.g., PUCCH resources) for the UE 102 to transmit a CSI report for each of the SSBs. In some embodiments, the UE 102 determines a time resource / frequency resource and / or a RACH occasion based on the SSB (e.g., indicated by the RS index) and the random access configuration parameters received in the system information, and transmits a second random access preamble at the time resource / frequency resource and / or the RACH occasion. In other embodiments, the UE 102 determines a time resource / frequency resource and / or a RACH occasion based on the SSB (e.g., indicated by the RS index) and the random access configuration parameters received in the RRC reconfiguration message of event 550, and transmits a second random access preamble at the time resource / frequency resource and / or the RACH occasion.

[0067] In other embodiments, the RS index (e.g., CSI-RS index) identifies one of the CSI-RSs. In some embodiments, the base station 104 determines or decodes the CSI-RS index indicated in the CSI report. In further embodiments, the base station 104 determines or decodes the CSI-RS index based on the radio resource (e.g., PUCCH resource) on which the base station 104 receives the CSI report for the CSI-RS. In some such embodiments, the base station 104 configures different radio resources for the UE 102 and transmits CSI reports for each of the CSI-SSBs. In some examples, the base station 104 includes in the RRC reconfiguration message of event 536 a configuration for configuring different radio resources (e.g., PUCCH resources) for the UE 102 to transmit CSI reports for each of the CSI-SSBs. In some embodiments, the UE 102 determines the time resource / frequency resource and / or RACH occasion based on the CSI-RS (e.g., indicated by the RS index) and the random access configuration parameters within the RRC reconfiguration message that the UE 102 receives in event 550. The UE 102 transmits a second random access preamble on the time resource / frequency resource and / or RCH occasion. In some embodiments, the random access configuration parameters indicate one or more associations between the CSI-RS, the RACH occasion, and / or the time resource / frequency resource.

[0068] In some embodiments, UE102 determines transmission characteristics (e.g., spatial transmission filters / parameters) based on or by referring to the RS index of the PDCCH order, and transmits the second random access preamble to TRP107-2 using the determined transmission characteristics. In some examples, UE102 derives the transmission characteristics using the reception characteristics for receiving the RS identified by the RS index (564). In some embodiments, the transmission characteristics include phase, power, and / or a transmission precoder. In some embodiments, UE102 further uses the DL and / or UL configuration parameters of event 550 to determine the transmission characteristics. In further embodiments, UE102 uses the configuration parameters within the system information of event 510 to determine the transmission characteristics. In some embodiments, UE102 determines transmission characteristics (e.g., spatial transmission filters / parameters) without relying on or referring to the RS index of the PDCCH order, and transmits the second random access preamble to TRP107-2 using the determined transmission characteristics.

[0069] In some embodiments, in response to the random access configuration parameters received in event 550, UE102 starts a random access procedure (598) after receiving the RS in event 564. In such embodiments, base station 104 does not transmit a PDCCH order and causes UE102 to execute the random access procedure 598.

[0070] In some embodiments, the RRC reconfiguration message of event 550 includes configuration parameters for the UE 102 to receive DL transmissions from the TRP 107-2 (e.g., for PDCCH configuration, search space configuration, and / or control resource set (CORESET) configuration). In some embodiments, the UE 102 receives a second random access response according to the configuration parameters. In other embodiments, the system information of event 510 includes configuration parameters for the UE 102 to receive a random access response from the TRP 107-2. In such embodiments, the UE 102 receives a second random access response according to the configuration parameters. In some embodiments, the UE 102 uses the reception characteristics for receiving the RS (564) to receive a second random access response from the TRP 107-2.

[0071] Although the TRP 107-2 is used in scenario 500A, the above description can be applied to a scenario where the TRP 107-3 is used instead of the TRP 107-2. In such a scenario, after successfully completing the random access procedure with the base station via the TRP 107-3 and the cell 125, similar to procedure 598, the UE performs DL and UL communications with the base station via the TRP 107-1 and the TRP 107-3 according to the first TA value and the second TA value, respectively.

[0072] In some scenarios or embodiments, the base station 104 transmits, via the TRP 107-1 or the TRP 107-2, a third TA command to the UE 102 that includes a first new TA value for updating a first TA value. In some embodiments, the third TA command is a MAC control element (CE). In response to receiving the third TA command and applying the first new TA value to the first UL synchronization, the UE 102 resumes the first TAT of the UE 102. In response to transmitting the third TA command, the base station 104 resumes the first TAT of the base station 104. In some scenarios or embodiments, the base station 104 transmits, via the TRP 107-1 or the TRP 107-2, a fourth TA command to the UE 102 that includes a second new TA value for updating a second TA value. In some embodiments, the fourth TA command is a MAC CE. In response to receiving the fourth TA command and applying the second new TA value to the second UL synchronization, the UE 102 resumes the second TAT. In some scenarios or embodiments, the base station 104 transmits, via the TRP 107-1 or the TRP 107-2, a single TA command to the UE 102 that includes the first new TA value and the second new TA value, and updates the first TA value and the second TA value, respectively. In some embodiments, the single TA command is a new or existing MAC control element (CE) (e.g., defined in 3GPP specification 38.321 V17.1.0).

[0073] In some embodiments, TRP107-1 generates timing information based on the UL transmission received from UE102 and transmits the timing information to base station 104. In some examples, the timing information indicates a propagation delay or a propagation delay shift. Based on the timing information received from TRP107-1, base station 104 determines whether to update the first TA value. In some embodiments, if the propagation delay or the propagation delay shift is greater than or equal to a first threshold, base station 104 determines to update the first TA value. Otherwise, if the propagation delay or the propagation delay shift is less than a second threshold, base station 104 determines not to update the first TA value. In some embodiments, when base station 104 determines to update the first TA value, base station 104 generates a first new TA value. In some embodiments, TRP107-2 generates timing information based on the UL transmission received from UE102 and transmits the timing information to base station 104. In some examples, the timing information indicates a propagation delay or a propagation delay shift. Based on the timing information received from TRP107-2, base station 104 determines whether to update the second TA value. In some embodiments, if the propagation delay or the propagation delay shift is greater than or equal to a third threshold, base station 104 determines to update the second TA value. Otherwise, if the propagation delay or the propagation delay shift is less than a fourth threshold, base station 104 determines not to update the first TA value. In some embodiments, when base station 104 determines to update the second TA value, base station 104 generates a second new TA value. Depending on the embodiment, the first, second, third, and fourth thresholds are the same or different.

[0074] Referring to FIG. 5B, scenario 500B is similar to scenario 500A, but the differences are described below. In scenario 500B, base station 104 transmits an RRC reconfiguration message containing DL configuration parameters for DL communication with base station 104 via TRP107-2 to UE 102 via TRP107-1 (549, 551). In some embodiments, base station 104 includes UL configuration parameters for UL communication with base station 104 via TRP107-1 in the RRC reconfiguration message (e.g., to configure or enable UL communication with base station 104 via TRP107-2). In some embodiments, base station 104 includes the DL configuration parameters in a CellGroupConfigIE and includes the CellGroupConfigIE in the RRC reconfiguration message. In some embodiments, base station 104 includes the DL configuration parameters in a BWP-UplinkDedicatedIE and includes the BWP-UplinkDedicatedIE in the RRC reconfiguration message. The RRC reconfiguration messages for events 549, 551 are the same as the RRC reconfiguration messages for events 548, 550, except that base station 104 excludes or refrains from including UL configuration parameters for UL communication with base station 104 via TRP107-2 in the RRC reconfiguration messages for events 549, 551. Instead, base station 104 transmits a different RRC reconfiguration message containing UL configuration parameters for UL communication with base station 104 via TRP107-2 to UE 102 via TRP107-1 (578, 580). In response, UE 102 transmits an RRC reconfiguration complete message to base station 104 via TRP107-1 (582, 584). In some embodiments, base station 104 includes the UL configuration parameters in a CellGroupConfigIE and includes the CellGroupConfigIE in the RRC reconfiguration messages for events 578, 580. In some embodiments, base station 104 includes the UL configuration parameters in a BWP-UplinkDedicatedIE and includes the BWP-UplinkDedicatedIE in the RRC reconfiguration message.

[0075] Blocks 549, 551, 552, 554, 556, 578, 580, 582, and 584 are collectively referred to as the TRP configuration procedure 596B in Figure 5B. After receiving the RRC reconfiguration message in event 538, after executing the CSI resource configuration and CSI reporting procedure 594, or after executing the TRP configuration procedure 596B with the base station 104, the UE 102 receives the RS from the base station 104 via the TRP 107-2 (562, 564). After executing the TRP configuration procedure 596A with the base station 104, the UE 102 executes a random access procedure with the base station 104 via the TRP 107-2 (598).

[0076] Referring next to Figure 5C, scenario 500C is similar to scenarios 500A and 500B with the different points described below.

[0077] After transmitting the RRC reconfiguration message (549, 550) or after receiving the RRC reconfiguration complete message (552, 554), the base station 104 transmits another RRC reconfiguration message including UL configuration parameters for UL communication between the base station 104 via the TRP 107-2 and the UE 102 via the TRP 107-2 (579, 581). The RRC reconfiguration messages of events 579, 581 are the same as the RRC reconfiguration messages of events 578, 580, except that the base station 104 transmits the RRC reconfiguration to the UE 102 via the TRP 107-2 instead of the TRP 107-1 (579, 581).

[0078] Blocks 549, 551, 552, 554, 556, 579, 581, 582, and 584 are collectively referred to as the TRP configuration procedure 596C in Figure 5C.

[0079] Referring next to Figure 5D, scenario 500D is similar to scenarios 500A, 500B, and 500C with the different points described below.

[0080] After UE 102 executes the TRP configuration procedures 596A, 596B, or 596C with the base station 104, UE 102 starts a random access procedure (599). In response to the start, UE 102 transmits a second random access preamble to the base station 104 via TRP 107-2 (566, 568). In response thereto, the base station 104 transmits a second random access response to UE 102 via TRP 107-1 instead of TRP 107-2 (571, 573).

[0081] Referring now to Figure 5E, scenario 500E is similar to scenarios 500A, 500B, 500C, and 500D with the differences described below.

[0082] In some embodiments, after receiving an RRC reconfiguration complete message at event 554, the base station 104 transmits a PDCCH order to UE 102 via TRP 107-1 (559, 560) and causes UE 102 to start a random access procedure 598 or 599 with the base station 104 via TRP 107-2, similar to events 558, 560.

[0083] Figures 6-14 are flow diagrams showing exemplary methods that a UE (e.g., UE 102) can perform to enable operation of multiple TA values under multiple TRP scenarios. Figures 6-14 show several ways in which a UE determines an action when one of a plurality of TATs expires and maintains multiple TA values. In some embodiments, the first TRP and the second TRP described below are, for example, TRP 107-1 and TRP 107-2. In another example, the first TRP and the second TRP described below are TRP 107-1 and TRP 107-3.

[0084] Some general descriptions are provided below, which can be applied to the following flow diagrams and / or embodiments.

[0085] In some embodiments, the UE performs DL reception from a first TRP (e.g., one of TRP107-1, TRP107-2, TRP107-3, TRP108-1, and / or TRP108-2), and / or UL transmission to the first TRP. In some such embodiments, the UE performs DL reception from a second TRP (e.g., one of TRP107-1, TRP107-2, TRP107-3, TRP108-1, and / or TRP108-2), and / or UL transmission to the second TRP. In some embodiments, the first TRP is located within the serving cell. In further embodiments, the second TRP is located within the serving cell. Alternatively, the second TRP is located in an adjacent cell. In some embodiments, the second TRP is located in an adjacent cell or a non-serving cell, where the adjacent cell or non-serving cell is a cell having a PCI different from that of the serving cell.

[0086] In some embodiments, each TRP (e.g., TRP107-1, TRP107-2, TRP107-3, TRP108-1, and / or TRP108-2) is associated with or identified by a TRP identifier. In some embodiments, a base station (e.g., base station 104 or 106) includes the TRP identifier in a UL configuration, and the UL configuration is transmitted by the base station to a UE (e.g., UE102) for UL transmission via the TRP identified by the TRP identifier. In some embodiments, the UL configuration includes DCI transmitted on a PDCCH, and / or a PUSCH configuration, a PUCCH configuration, and / or an SRS configuration, which are included in an RRC message (e.g., an RRC reconfiguration message or an RRC resume message) transmitted by the base station to the UE. In some embodiments, the UL transmission includes PUSCH transmission, PUCCH transmission, and / or SRS transmission. In some embodiments, the base station includes the TRP identifier in a DL configuration, and the DL configuration is transmitted by the base station to UE102 for DL transmission via the TRP identified by the TRP identifier. In some embodiments, the DL configuration includes DCI transmitted on a PDCCH, and / or a CSI resource configuration, a PDSCH configuration, and / or a PDCCH configuration, which are included in an RRC message (e.g., an RRC reconfiguration message or an RRC resume message) transmitted by the base station to the UE. In some embodiments, the DL transmission includes CSI-RS transmission, SSB transmission, PDSCH transmission, and / or PDCCH transmission.

[0087] In other embodiments, the base station does not transmit the TRP identifier to the UE and uses an implicit indication to indicate the TRP to the UE. In some embodiments, the implicit indication is one of the following configuration parameters, namely, CORESETPoolIndex, the value or value candidates of CORESETPoolIndex, dataScrambleIdentityPDSCH, dataScrambleIdentityPDSCH2-r16, or PUCCH-ResourceGroup-r16. In such embodiments, the UE derives the TRP (identifier) from the implicit indication. In some embodiments, the base station transmits an RRC message (e.g., an RRC reconfiguration message or an RRC resume message) including the configuration parameter to the UE.

[0088] In some embodiments, the base station configures or indicates a first TRP identifier to the UE. In some embodiments, the UE derives the first TRP identifier and / or identifier value. In some embodiments, the base station configures or indicates a second TRP identifier and / or identifier value to the UE. In some embodiments, the UE derives the second TRP identifier and / or identifier value.

[0089] In some cases, the UE maintains multiple TA values. In some such embodiments, the UE maintains multiple TA values and all of the multiple TA values are indicated or signaled to the UE. In further such embodiments, the UE maintains multiple TA values and all of the multiple TA values are derived by the UE. In some embodiments, the UE maintains multiple TA values and at least one of the some TA values is indicated or signaled to the UE and at least one of the remaining TA values is derived by the UE. In further embodiments, the UE maintains or operates on multiple TA values in the serving cell. In some embodiments, the base station indicates or configures each ID of the multiple TA values to the UE. In some embodiments, the UE derives each ID of the multiple TA values. In some such embodiments, each of the multiple TA values has an individual ID. In some such embodiments, the UE maintains multiple TA values for or within the serving cell.

[0090] In some cases, the base station configures or activates a first set of serving cells for the UE. In some cases, the base station configures or activates a second set of serving cells for the UE. In some embodiments, the first set of serving cells has the same serving cell elements as the second set of serving cells. In some embodiments, the first set of serving cells has different serving cell elements from the second set of serving cells.

[0091] In some cases, the base station configures or activates a third set of serving cells for the UE. In some embodiments, the third set of serving cells at least includes the first set of serving cells. In further embodiments, the third set of serving cells at least includes the second set of serving cells. In some embodiments, the third set of serving cells at least includes the first set of serving cells and the second set of serving cells. In some embodiments, the third set of serving cells is a union of the first set of serving cells and the second set of serving cells. In some embodiments, the third set of serving cells is an intersection of the first set of serving cells and the second set of serving cells.

[0092] In some cases, the UE can maintain a first TA value among a plurality of TA values. In some cases, the UE can maintain a second TA value among a plurality of TA values. In some embodiments, the first TA value can be associated with a first TRP. In some embodiments, the second TA value can be associated with a second TRP.

[0093] According to embodiments, the first TA value is (i) applied to or associated with the first set of serving cells, (ii) applied to or associated with the first TRP, (iii) applied to or associated with UL channel / RS transmissions sent to the first TRP, and / or (iv) applied to or associated with UL channel / RS transmissions related to the first TRP identifier and / or identifier value.

[0094] In some embodiments, the second TA value is (i) applied to or associated with a second set of serving cells, (ii) applied to or associated with a second TRP, (iii) applied to or associated with UL channel / RS transmissions sent to the second TRP, and / or (iv) applied to or associated with UL channel / RS transmissions related to a second TRP identifier and / or identifier value.

[0095] In some cases, the base station indicates or configures, for the UE, the ID of the first TA value. In some cases, the UE derives the ID of the first TA value. In some cases, the base station indicates or configures, for the UE, the ID of the second TA value. In some cases, the UE derives the ID of the second TA value.

[0096] In some cases, the base station configures or indicates, for the UE, one or more TA groups. In some embodiments, one TA group (TAG) includes or is associated with one or more serving cells and / or indices. In some embodiments, each serving cell included in or associated with the same TAG uses or operates with one or more TA values. In some embodiments, one TAG includes or is associated with one or more TA values. In some embodiments, the UE is indicated or configured by or derives the ID of each of one or more TA groups. In some such embodiments, each TAG has a separate ID.

[0097] In some cases, the base station configures or indicates a first TAG for the UE. In some embodiments, the first TAG is within one or more TA groups. In some embodiments, the first TA value or the ID of the first TA value is associated with or included in the first TAG.

[0098] In some cases, the base station configures or indicates a second TAG for the UE. In some embodiments, the second TAG is within one or more TA groups. In some embodiments, the second TA value or the ID of the second TA value is associated with or included in the second TAG.

[0099] In some cases, the first TA value and the second TA value are associated with or included in the same TAG.

[0100] In some embodiments, the first TAG is associated with a first TRP or a first TRP identifier and / or an identifier value. In some embodiments, the first TAG includes or is associated with a first set of serving cells. In some embodiments, the first set of serving cells is composed of or associated with a first TRP or a first TRP identifier and / or an identifier value. In some embodiments, in each serving cell of the first set of serving cells, at least one CORESET is composed of or associated with CORESETPoolIndex#0.

[0101] In some embodiments, the first TAG includes or is associated with one or more TA values, and the one or more TA values are (i) applied to or associated with a first set of serving cells, (ii) applied to or associated with a first TRP, (iii) applied to or associated with UL channel / RS transmission related to the first TRP or the first TRP identifier and / or identifier value, and / or (iv) applied to or associated with a third set of serving cells.

[0102] In some embodiments, the second TAG is associated with a second TRP or a second TRP identifier and / or identifier value. In some embodiments, the second TAG includes or is associated with a second set of serving cells. In some embodiments, the second set of serving cells is composed of or associated with a second TRP or a second TRP identifier and / or identifier value. In some embodiments, in each serving cell of the second set of serving cells, at least one CORESET is composed of or associated with CORESETPoolIndex#1.

[0103] In some embodiments, the second TAG includes or is associated with one or more TA values, and the one or more TA values are (i) applied to or associated with a second set of serving cells, (ii) applied to or associated with a second TRP, (iii) applied to or associated with UL channel / RS transmission related to the second TRP or the second TRP identifier and / or identifier value, and / or (iv) applied to or associated with a third set of serving cells.

[0104] In some cases, the base station indicates or configures the ID of the first TAG for the UE. In some cases, the UE derives the ID of the first TAG. In some cases, the base station indicates or configures the ID of the second TAG for the UE. In some cases, the UE derives the ID of the second TAG.

[0105] In some cases, the base station indicates or configures a third TAG for the UE. In some embodiments, the third TAG is within one or more TA groups. In some embodiments, the UE can indicate or configure the ID of the third TAG, or the UE can derive the ID of the third TAG.

[0106] In some embodiments, the third TAG is associated with the first TRP or the first TRP identifier and / or identifier value. In some embodiments, the third TAG is associated with the second TRP or the second TRP identifier and / or identifier value. In some embodiments, the third TAG includes or is associated with a third set of serving cells.

[0107] In some embodiments, the third TAG includes or is associated with one or more TA values. In some embodiments, the third TAG includes or is associated with one or more TA values, where the one or more TA values include the first TA value and / or the second TA value.

[0108] In some embodiments, when the base station indicates or configures a third TAG for the UE, the UE determines to expect at least one of the following: (i) all serving cells included in or associated with the third TAG are configured in a multi-TRP (M-TRP) mode by the base station (e.g., the M-TRP mode is a single DCI (S-DCI) M-TRP mode or a multi-DCI (M-DCI) M-TRP mode), (ii) all serving cells included in or associated with the third TAG are configured by the base station with a CORESETPoolIndex, and / or (iii) all serving cells included in or associated with the third TAG are configured by the base station with or associated with a first TRP identifier and / or identifier value and a second TRP identifier and / or identifier value.

[0109] In some embodiments, when the base station configures a third TAG for the UE, the base station performs one or some of the following: (i) configuring all serving cells included in or associated with the third TAG in an M-TRP mode (e.g., the M-TRP mode is an S-DCI M-TRP mode or an M-DCI M-TRP mode), (ii) configuring all serving cells included in or associated with the third TAG with a CORESETPoolIndex, and / or (iii) configuring all serving cells included in or associated with the third TAG with or associating them with a first TRP identifier and / or identifier value and a second TRP identifier and / or value.

[0110] In some cases, the base station configures or indicates one or more primary TAGs (PTAGs) for the UE. In some embodiments, the base station configures or indicates two PTAGs for the UE. In some cases, the base station configures or indicates one or more secondary TAGs (STAGs) for the UE.

[0111] In some cases, the first TAG is a PTAG. In some embodiments, the first set of serving cells includes a primary cell (PCell) or a primary secondary cell (PSCell). In some embodiments, the first TAG is an STAG. In some embodiments, the first set of serving cells does not include a PCell or a PSCell.

[0112] In some cases, the second TAG is a PTAG. In some embodiments, the second set of serving cells includes a PCell or a PSCell. In some embodiments, the second TAG is an STAG. In some embodiments, the second set of serving cells does not include a PCell or a PSCell.

[0113] In some cases, the third TAG is a PTAG. In some embodiments, the third set of serving cells includes a PCell or a PSCell. In some embodiments, the third TAG is an STAG. In some embodiments, the third set of serving cells does not include a PCell or a PSCell.

[0114] In some cases, the base station configures or indicates one or more time alignment timers (TATs) for the UE. In some embodiments, the one or more TATs are configured or indicated for an active BWP or in a serving cell. In some embodiments, the base station configures or indicates a first TAT within an active BWP or in a serving cell for the UE. In some embodiments, the base station configures or indicates a second TAT for an active BWP or a serving cell for the UE. In some embodiments, the UE maintains the first TAT. In some embodiments, the UE maintains the second TAT. In some embodiments, the base station also maintains the first TAT and / or the second TAT.

[0115] In some embodiments, the first TAT is associated with the first TAG. In further embodiments, the first TAT is associated with or applied to the first set of serving cells. In some embodiments, the second TAT is associated with the second TAG. In further embodiments, the second TAT is associated with or applied to the second set of serving cells.

[0116] In some embodiments, the base station configures or indicates the ID of the first TAT for the UE. In further embodiments, the UE derives the ID of the first TAT. In some embodiments, the base station configures or indicates the ID of the second TAT for the UE. In further embodiments, the UE derives the ID of the second TAT.

[0117] In some cases, the base station configures or indicates for the UE an active BWP of the serving cell or a third TAT for the serving cell. In some embodiments, the third TAT is associated with or applied to the third set of serving cells. In some embodiments, the UE maintains the third TAT. In some embodiments, the base station also maintains the third TAT. In some embodiments, the base station configures or indicates the ID of the third TAT for the UE. In further embodiments, the UE derives the ID of the third TAT.

[0118] In some cases, the first TA value and the second TA value belong to or are associated with the same TAG (e.g., the third TAG). In some embodiments, the ID of the first TA value and the ID of the second TA value are included in the same TAG (e.g., the third TAG). In some cases, the first TA value and the second TA value belong to or are associated with different TAGs (e.g., the first TAG and the second TAG). In some embodiments, the ID of the first TA value and the ID of the second TA value are included in different TAGs (e.g., the first TAG and the second TAG).

[0119] In some cases, whether the first TA value has expired and whether the second TA value has expired are controlled or associated by the same TAT (for example, the third TAT). Further, in some cases, whether the first TA value has expired and whether the second TA value has expired are controlled or associated by different TATs (for example, the first TAT and the second TAT).

[0120] In some cases, whether the first TAG is uplink time-aligned and whether the second TAG is uplink time-aligned are controlled or associated by the same TAT (for example, the third TAT). Further, in some cases, whether the first TAG is uplink time-aligned and whether the second TAG is uplink time-aligned are controlled or associated by different TATs (for example, the first TAT and the second TAT).

[0121] In some cases, whether the first set of serving cells is uplink time-aligned and whether the second set of serving cells is uplink time-aligned are controlled or associated by the same TAT (for example, the third TAT). Further, in some cases, whether the first set of serving cells is uplink time-aligned and whether the second set of serving cells is uplink time-aligned are controlled or associated by different TATs (for example, the first TAT and the second TAT).

[0122] In some embodiments, the base station configures a first TAG and a second TAG respectively for UL transmission to a first TRP and a second TRP for the UE. In some embodiments, the base station transmits a first RRC message and a second RRC message to the UE, which include a first TAG configuration and a second TAG configuration that configure the first TAG and the second TAG respectively. In some embodiments, the first TAG configuration and the second TAG configuration each include a first TAG ID and a second TAG ID respectively for identifying the first TAG and the second TAG. In some embodiments, the first TAG configuration and the second TAG configuration each include a timer value for the first TAT / a timer value for the first TAT and a timer value for the second TAT / a timer value for the second TAT for the first TAG and the second TAG respectively. In some embodiments, the first RRC message and the second RRC message are the same RRC message (e.g., the same instance), or different RRC messages (e.g., different instances or different types of RRC messages). In some embodiments, the first RRC message and the second RRC message are RRC setup messages, RRC reconfiguration messages, and / or RRC resume messages. The UE associates a first TA value and a second TA value with the first TAG and the second TAG respectively. In some embodiments, the first TAG is associated with a first TRP or a first TRP identifier and / or an identifier value. In some embodiments, the first TAG is associated with a specific serving cell operated by the first TRP and configured for the UE. In some embodiments, the first TAG is associated with an additional serving cell operated by the first TRP and configured for the UE. In some embodiments, the base station indicates or configures the association within the first RRC message. In some embodiments, the second TAG is associated with a second TRP or a second TRP identifier and / or an identifier value. In some embodiments, the second TAG is associated with a specific serving cell or a non-serving cell, and the base station indicates or configures the association within the second RRC message.

[0123] In other embodiments, the base station configures a single TAG (e.g., a third TAG) for UL transmission to the first TRP and the second TRP for the UE. In some embodiments, the base station transmits a first RRC message (e.g., an RRC setup, RRC reconfiguration, and / or RRC resume message) including a single TAG configuration for configuring the TAG to the UE. In some embodiments, the TAG configuration includes a single TAG ID for identifying the TAG. In some embodiments, the TAG configuration includes a timer value for the first TAT / a timer value for the first TAT and a timer value for the second TAT / a timer value for the second TAT. In further embodiments, the TAG configuration includes a timer value for the first TAT / a timer value for the first TAT, and the base station transmits a second RRC message (e.g., an RRC setup, RRC reconfiguration, and / or RRC resume message) including a timer value for the second TAT. The UE associates the first TA value and the second TA value with the TAG. In some embodiments, the TAG is associated with (i) the first TRP or the first TRP identifier, and / or an identifier value, and (ii) the second TRP or the second TRP identifier. In some embodiments, the TAG is operated by the first TRP and associated with a specific serving cell configured for the UE. In some embodiments, the TAG is operated by the first TRP and associated with an additional serving cell configured for the UE. In some embodiments, the base station indicates or configures the association within the first RRC message. In some embodiments, the TAG is associated with the second TRP or the second TRP identifier, and / or an identifier value. In some embodiments, the TAG is associated with a specific serving cell or a non-serving cell, and the base station indicates or configures the association within the second RRC message.

[0124] In some embodiments, the base station is configured such that a particular serving cell is associated with a first TRP or a first TRP identifier and / or an identifier value. In some embodiments, the base station configures a first control resource set (CORESET) associated with a particular serving cell or the first TRP. In a further embodiment, the base station configures CORESETPoolIndex#0 to identify the first CORESET. In some embodiments, the base station configures the first CORESET and / or transmits a third RRC message (e.g., an RRC setup message, an RRC reconfiguration message, or an RRC resume message) including CORESETPoolIndex#0 to the UE. Accordingly, the UE monitors the PDCCH on the first CORESET to receive DCI from the base station, which means that the UE monitors the PDCCH or receives DCI from the base station via the first TRP (i.e., from the first TRP). In such a case, the UE determines that CORESETPoolIndex#0 indicates a particular TRP of the base station (i.e., the first TRP).

[0125] In some embodiments, the base station is configured to associate a particular serving cell with a second TRP or a second TRP identifier and / or an identifier value. In other embodiments, the second TAG is associated with a non-serving cell, and the base station indicates or configures the association within a second RRC message. In some embodiments, the base station configures a non-serving cell associated with a second TRP or a second TRP identifier and / or an identifier value. In some embodiments, the base station configures a second CORESET to be associated with a particular serving cell, a non-serving cell, or a second TRP. In a further embodiment, the base station configures CORESETPoolIndex#1 to identify the second CORESET. In some embodiments, the base station configures the second CORESET and / or transmits a third RRC message (e.g., an RRC setup, RRC reconfiguration, and / or RRC resume message) including CORESETPoolIndex#1 to the UE. Accordingly, the UE monitors the PDCCH on the second CORESET to receive DCI from the base station, which means that the UE monitors the PDCCH or receives DCI from the base station via the second TRP (i.e., from the second TRP). In some such embodiments, the UE determines that CORESETPoolIndex#1 indicates a particular TRP (i.e., the second TRP).

[0126] In some embodiments, the base station constructs, in addition to the above TAG ID, a first ID for identifying a first TA value for the UE. In some embodiments, the base station includes the first ID in the above RRC message. In further embodiments, the base station includes the first ID in the first TA command. In other embodiments, the UE derives or determines the first ID and associates the first ID with the first TA value. Similarly, in addition to the above TAG ID, the base station constructs a second ID for identifying a second TA value for the UE. In some embodiments, the base station includes the second ID in the above RRC message. In further embodiments, the base station includes the second ID in the second TA command. In other embodiments, the UE derives or determines the second ID and associates the second ID with the second TA value.

[0127] More generally, in some embodiments, the base station constructs or indicates to the UE a first index for the first TRP or related to the first TRP. In some embodiments, the UE derives or determines the first index. In some embodiments, the first index is one of (i) the first TRP identifier and / or identifier value, (ii) the ID of the first TAG, (iii) the ID of the first TA value, and / or (iv) the ID of the first TAT.

[0128] More generally, in further embodiments, the base station constructs or indicates to the UE a second index for the second TRP / associated with the second TRP. In some embodiments, the UE derives the second index. In some embodiments, the second index is one of (i) the second TRP identifier and / or identifier value, (ii) the ID of the second TAG, (iii) the ID of the second TA value, and / or (iv) the ID of the second TAT.

[0129] In some cases, the first TAT is started or resumed by the UE or the base station in response to at least one of the following: (i) The UE receives a timing advance command MAC CE, and the timing advance command MAC CE indicates or updates timing adjustment related information for the first TA value or the first TAG or the first TAT. (ii) The UE receives a timing advance command in the RAR response or in the MAC payload for the RAR response, where (a) in some embodiments, the RAR response or the timing advance command is transmitted or associated by the first TRP, (b) in some embodiments, the RAR response or the timing advance command is associated with the first index, and / or (c) in some embodiments, the RAR response and / or the timing advance command indicates that the RAR response or the timing advance command is for the first TRP. And / or (iii) The UE receives an absolute timing advance command in response to the transmission of an MSGA including a C-RNTI MAC CE, where (a) in some embodiments, the response to the MSGA or the absolute timing advance command is transmitted or associated by the first TRP, (b) in some embodiments, the response to the MSGA or the absolute timing advance command is associated with the first index, and / or (c) in some embodiments, the response to the MSGA or the absolute timing advance command indicates that this response is for the first TRP.

[0130] In some cases, the second TAT is started or resumed in response to at least one of the following: (i) The UE receives a timing advance command MAC CE, where in some embodiments, the timing advance command MAC CE indicates or updates timing adjustment related information for a second TA value or a second TAG or a second TAT. (ii) The UE receives a timing advance command in an RAR response or in the MAC payload for an RAR response, where (a) in some embodiments, the RAR response or the timing advance command is transmitted or associated by a second TRP, (b) in some embodiments, the RAR response or the timing advance command is associated with a second index, and / or (c) in some embodiments, the RAR response and / or the timing advance command indicates that the RAR response or the timing advance command is for a second TRP. And / or (iii) The UE receives an absolute timing advance command in response to transmitting an MSGA including a C-RNTI MAC CE, where (a) in some embodiments, the response to the MSGA or the absolute timing advance command is transmitted or associated by a second TRP, (b) in some embodiments, the response to the MSGA or the absolute timing advance command is associated with a second index, and / or (c) in some embodiments, the response to the MSGA or the absolute timing advance command indicates that this response is for a second TRP.

[0131] In some cases, the third TAT is started or resumed in response to at least one of the following: (i) The UE receives a timing advance command MAC CE, where in some embodiments, the timing advance command MAC CE indicates or updates timing adjustment related information for at least one of the following: (a) a first TA value, a first TAG, or a first TAT, (b) a second TA value, a second TAG, or a second TAT, and / or (c) a third TA value, a third TAG, or a third TAT. (ii) The UE receives a timing advance command in a RAR response or in a MAC payload for a RAR response, where (a) in some embodiments, the RAR response or the timing advance command is transmitted or associated by a first TRP and / or a second TRP, (b) in some embodiments, the RAR response or the timing advance command is associated with a first index and / or a second index, and / or (c) in some embodiments, the RAR response and / or the timing advance command indicates that the RAR response or the timing advance command is for a first TRP and / or a second TRP. And / or (iii) The UE receives an absolute timing advance command in response to transmitting an MSGA including a C-RNTI MAC CE, where (a) in some embodiments, the response to the MSGA or the absolute timing advance command is transmitted or associated by a first TRP and / or a second TRP, (b) in some embodiments, the response to the MSGA or the absolute timing advance command is associated with a first index and / or a second index, and / or (c) in some embodiments, the response to the MSGA or the absolute timing advance command indicates that this response is for a first TRP and / or a second TRP.

[0132] Referring first to FIG. 6, a UE (e.g., UE 102) implements an exemplary method 600 for operating multiple TA values under multiple TRP scenarios.

[0133] Method 600 begins at block 602, where the UE performs DL communication and / or UL communication with the base station (e.g., events 504, 506, 508, 510, 512, 514, 516, 518, 590, 522, 524, 526, 528, 532, 534, 592, 536, 538, 540, 542, 544, 546, 594, 549, 551, 552, 554, 556, 562, 564). At block 604, the UE receives from the base station a configuration that enables the manipulation of two TA values (e.g., events 548, 550, 596A, 578, 580, 596B, 579, 581, 596C). At block 606, the UE receives from the base station a first TA value and a second TA value (e.g., events 516, 518, 570, 571, 572, 573, 590, 598, 599). At block 608, when the UE receives the first TA value (e.g., upon reception, after reception, or in response to reception), it starts or resumes a first TAT to maintain the first UL synchronization with the base station. At block 610, when the UE receives the second TA value, it starts or resumes a second TAT to maintain the second UL synchronization with the base station. At block 611, the UE detects whether the first TAT or the second TAT has expired. If the UE detects that the first TAT has expired, the flow proceeds to block 612. At block 612, the UE stops transmitting to the base station the UL transmissions associated with the first TA value. If the UE detects that the second TAT has expired, the flow proceeds to block 614. At block 614, the UE stops transmitting to the base station the UL transmissions associated with the second TA value.

[0134] When the first TAT expires and the UE stops transmitting to the first TRP, the UE can continue UL transmission associated with the second TAT to the second TRP. Conversely, when the second TAT expires and the UE stops transmitting to the second TRP, the UE can continue UL transmission associated with the second TAT to the first TRP. For example, in some embodiments, the UE reports to the base station that synchronization with the first TRP is lost (e.g., TAT expiration), and the base station stops scheduling transmission to the first TRP but continues scheduling transmission to the second TRP.

[0135] In some embodiments, the UE maintains the first UL synchronization and the second UL synchronization with the base station based on the first TA value and the second TA value respectively. In some embodiments, the UE applies the first TA value and the second TA value to the first UL transmission and the second UL transmission with the base station on the serving cell respectively. In other embodiments, the UE applies the first TA value and the second TA value and transmits the first UL transmission and the second UL transmission on the serving cell and the non-serving cell with the base station respectively.

[0136] In some embodiments, the UE receives the first TA value in the first random access response, the first MAC CE, or the first MAC PDU from the base station. In some embodiments, the UE receives the second TA value in the second random access response, the second MAC CE, or the second MAC PDU from the base station. In some embodiments, the first MAC CE and the second MAC CE are the same MAC CE. In further embodiments, the first MAC CE and the second MAC CE are different MAC CEs having the same MAC CE format or different MAC CE formats. In some embodiments, the first MAC PDU and the second MAC PDU are the same MAC PDU. In further embodiments, the first MAC PDU and the second MAC PDU are different MAC PDUs.

[0137] A more detailed description of the elements of method 600 is described herein, particularly with respect to the above general description. For example, in some embodiments, (i) the first TA value and the second TA value shown in block 606 are described in the description of the first TA value and the second TA value described with respect to the above general description, and (ii) the first TAT and the second TAT shown in blocks 608 and 610 are described in the description of the first TAT and the second TAT described with respect to the above general description.

[0138] Next, referring to FIG. 7A, a UE (e.g., UE 102) implements an exemplary method 700A of operating on a plurality of TA values under a plurality of TRP scenarios.

[0139] Method 700A begins at block 702. Blocks 702, 704, 706, 708, 710, and 711A are similar to blocks 602, 604, 606, 608, 610, and 611. If the UE detects that the first TAT has expired, the flow proceeds to block 712A. At block 712A, the UE flushes the HARQ buffers of the first set of HARQ processes, where the first set of HARQ processes is associated with PUSCH transmissions to which the UE applied the first TA value. If the UE detects that the second TAT has expired, the flow proceeds to block 714A. At block 714A, the UE flushes the HARQ buffers of the second set of HARQ processes, where the second set of HARQ processes is associated with PUSCH transmissions to which the UE applied the second TA value.

[0140] FIG. 7B shows an exemplary method 700B that is similar to scenario 700A shown in FIG. 7A, but method 700B differs in that it includes blocks 711B, 712B, and 714B, which are described below.

[0141] In block 711B, the UE detects whether both the first TAT and the second TAT have expired. If the UE detects that both the first TAT and the second TAT have expired, the flow proceeds to block 712B. In block 712B, the UE flushes the HARQ buffer of the HARQ process associated with the first PUSCH transmission and the second PUSCH transmission to which the UE applied the first TA value and the second TA value, respectively. If the UE does not detect that both the first TAT and the second TAT have expired, the flow proceeds to block 714B. In block 714B, the UE refrains from flushing the HARQ buffer.

[0142] Similar to method 600, a more detailed description of the elements of method 700 is generally detailed above.

[0143] In some cases, the UE is signaled by or consists of one or more HARQ processes in the serving cell. In some embodiments, the UE is signaled by or consists of one or more HARQ processes within each of one or more serving cells. For example, the UE is signaled by or consists of up to 16 HARQ processes in the serving cell. As another example, the UE is signaled by or consists of up to 16 HARQ processes in each of one or more serving cells, and each of the serving cells is adapted to be signaled by or consist of up to 16 HARQ processes.

[0144] In some cases, the UE is signaled or configured by a first set of HARQ processes. In some cases, the UE derives a first set of HARQ processes. In some embodiments, the UE is signaled or configured by a first set of HARQ processes in each of a first set of serving cells. In some embodiments, the UE derives a first set of HARQ processes in each of a first set of serving cells. In some embodiments, some elements or ID numbers in each of the first set of HARQ processes are different in each of the first set of serving cells. In further embodiments, some elements or ID numbers in each of the first set of HARQ processes are the same in each of the first set of serving cells. For example, when the first set of serving cells includes serving cell #0 and serving cell #1, the first set of HARQ processes in serving cell #0 for some such examples are HARQ processes #1, #2, and #5. However, the first set of HARQ processes in serving cell #1 are HARQ processes #1, #5, and #9.

[0145] In some cases, the UE is signaled or configured by a second set of HARQ processes. In some cases, the UE may derive a second set of HARQ processes. In some embodiments, the UE is signaled or configured by a second set of HARQ processes in each of a second set of serving cells. In some embodiments, the UE derives a second set of HARQ processes in each of a second set of serving cells. In some embodiments, some elements or ID numbers in each of the second set of HARQ processes are different in each of the second set of serving cells. In some embodiments, some elements or ID numbers in each of the second set of HARQ processes are the same in each of the first set of serving cells. For example, if the second set of serving cells includes serving cell #0 and serving cell #1, the second set of HARQ processes in serving cell #0 are HARQ processes #3, #6, and #11. However, the second set of HARQ processes for serving cell #1 are HARQ processes #2, #4, and #8.

[0146] In some embodiments, in at least one serving cell, elements in a first set of HARQ processes are orthogonal to elements in a second set of HARQ processes. In some embodiments, in at least one serving cell, each value of the HARQ process ID in a first set of HARQ processes is different from the value in a second set of HARQ processes. In some embodiments, in at least one serving cell, the values of the HARQ process ID in a first set of HARQ processes are not the same as any of the values in the first set of HARQ processes. For example, if both the first set of serving cells and the second set of serving cells include serving cell #0 and serving cell #1, the first set of HARQ processes in serving cell #0 are HARQ processes #1, #2, and #5. However, the first set of HARQ processes in serving cell #1 are HARQ processes #1, #5, and #9. The second set of HARQ processes in serving cell #0 are HARQ processes #3, #6, and #11. However, the second set of HARQ processes in serving cell #1 are HARQ processes #2, #4, and #8.

[0147] In some cases, the first set of HARQ processes is associated with one of the candidate values of the TRP identifier. In some embodiments, the first set of HARQ processes is associated with one of the candidate values of the CORESETPoolIndex. In some embodiments, the first set of HARQ processes is associated with CORESETPoolIndex #0. In a further embodiment, the first set of HARQ processes is associated with CORESETPoolIndex #1.

[0148] In some cases, the second set of HARQ processes is associated with one of the candidate values of the TRP identifier. In some embodiments, the second set of HARQ processes is associated with one of the candidate values of the CORESETPoolIndex. In some embodiments, the second set of HARQ processes is associated with CORESETPoolIndex #1. In a further embodiment, the second set of HARQ processes is associated with CORESETPoolIndex #0.

[0149] In some cases, the first set of HARQ processes is associated with a first index. In a further case, the second set of HARQ processes is associated with a second index.

[0150] In some cases, for the HARQ processes in the first set of HARQ processes, the HARQ process includes at least one of the following attributes. (i) In some embodiments, the HARQ process is used to transmit a UL transmission, where the UL transmission is transmitted by a spatial relationship, UL / joint TCI state, or spatial transmission filter / parameters derived from a source RS that is associated with or includes a first TA value. (ii) In some embodiments, the HARQ process is used to transmit a UL transmission, where the UL transmission is transmitted using a first TA value. And / or, (iii) In some embodiments, the HARQ process is used to transmit a UL transmission, where the UL transmission is associated with or includes a first TA value.

[0151] In some cases, for the HARQ processes in the second set of HARQ processes, the HARQ process includes at least one of the following attributes: (i) The HARQ process is used to transmit a UL transmission, where the UL transmission is associated with a second TA value or transmitted by a spatial relationship, UL / joint TCI state, or spatial transmission filter / parameters derived from a source RS that it includes. (ii) The HARQ process is used to transmit a UL transmission, where the UL transmission is transmitted using a second TA value. And / or, (iii) The HARQ process is used to transmit a UL transmission, where the transmission is associated with or includes a second TA value.

[0152] In some cases, the base station signals or configures one HARQ entity in the serving cell for the UE. In some embodiments, the base station signals or configures only one HARQ entity in the serving cell for the UE. In some embodiments, the base station signals or configures one HARQ entity for each of the first set of serving cells for the UE. In some embodiments, the base station signals or configures one HARQ entity for each of the second set of serving cells for the UE. In some embodiments, the base station signals or configures one HARQ entity in at least one serving cell in the first set of serving cells for the UE. In some embodiments, the base station signals or configures one HARQ entity in at least one serving cell in the second set of serving cells for the UE. In some embodiments, one or more of each of the first set of serving cells are signaled or configured by the base station with one HARQ entity. In some embodiments, one or more of each of the second set of serving cells are signaled or configured by the base station with one HARQ entity.

[0153] In some embodiments, the first set of HARQ processes may be included in or belong to the HARQ entity of the first serving cell. In some embodiments, the second set of HARQ processes may be included in or belong to the HARQ entity of the first serving cell.

[0154] In some embodiments, the first serving cell is associated with or included in the first set of serving cells. In some embodiments, the first serving cell is associated with or included in the second set of serving cells. In some embodiments, the first TAG is associated with or included in the third set of serving cells.

[0155] In some cases, the base station signals or configures multiple HARQ entities within the serving cell for the UE. In some embodiments, the base station signals or configures multiple HARQ entities in each of the first set of serving cells for the UE. In some embodiments, the base station signals or configures multiple HARQ entities in each of the second set of serving cells for the UE. In some embodiments, the base station signals or configures multiple HARQ entities in at least one serving cell in the first set of serving cells for the UE. In some embodiments, the base station signals or configures multiple HARQ entities in at least one serving cell in the second set of serving cells for the UE. In some embodiments, one or more of each of the first set of serving cells are signaled or configured by multiple HARQ entities. In some embodiments, one or more of each of the second set of serving cells are signaled or configured by multiple HARQ entities.

[0156] In some embodiments, the base station signals or configures, for the UE, a first HARQ entity in a second serving cell. In some embodiments, the base station signals or configures, for the UE, a second HARQ entity in the second serving cell.

[0157] In some embodiments, the second serving cell is associated with or included in a first set of serving cells. In some embodiments, the second serving cell is associated with or included in a second set of serving cells. In some embodiments, the second serving cell is associated with or included in a third set of serving cells.

[0158] In some embodiments, the first HARQ entity is associated with a first TRP or a first TRP identifier and / or an identifier value. In some embodiments, the first HARQ entity includes a first TRP identifier and / or an identifier value. For example, the first HARQ entity is associated with or includes CORESETPoolIndex#0. In some embodiments, the first HARQ entity includes or is associated with a first set of HARQ processes.

[0159] In some embodiments, the second HARQ is associated with a second TRP or a second TRP identifier and / or an identifier value. In some embodiments, the second HARQ entity includes a second TRP identifier and / or an identifier value. For example, the second HARQ entity is associated with or includes CORESETPoolIndex#1. In some embodiments, the second HARQ entity includes or is associated with a second set of HARQ processes.

[0160] In some embodiments, the base station indicates or signals an element included in a first set of HARQ processes or a HARQ process ID. In some embodiments, the base station indicates or signals an element included in a first set of HARQ processes or a HARQ process ID by at least one of DCI signaling, MAC-CE, or RRC signaling. In some embodiments, the base station indicates or signals an element included in a first set of HARQ processes or a HARQ process ID via a bitmap. In some embodiments, the base station indicates or signals an element included in a first set of HARQ processes or a HARQ process ID. In some embodiments, the base station indicates or signals an element included in a first set of HARQ processes or a HARQ process ID by at least one of DCI signaling, MAC-CE, or RRC signaling. In some embodiments, the base station indicates or signals an element included in a first set of HARQ processes or a HARQ process ID by a bitmap.

[0161] In some embodiments, the base station indicates or signals an element included in the second set of HARQ processes or a HARQ process ID. In some embodiments, the base station indicates or signals an element included in the second set of HARQ processes or a HARQ process ID by at least one of DCI signaling, MAC-CE, or RRC signaling. In some embodiments, the base station indicates or signals an element included in the second set of HARQ processes or a HARQ process ID by a bitmap. In some embodiments, the base station updates or changes an element included in the second set of HARQ processes or a HARQ process ID. In some embodiments, the base station updates or changes an element included in the second set of HARQ processes or a HARQ process ID by at least one of DCI signaling, MAC-CE, or RRC signaling. In some embodiments, the base station updates or changes an element included in the second set of HARQ processes or a HARQ process ID by a bitmap.

[0162] In some cases, if the UL transmission (e.g., UL data) is associated with the first TRP or the first TRP identifier and / or identifier value, the UL transmission is associated with or uses a HARQ process in the first set of HARQ processes.

[0163] In some cases, if the UL transmission (e.g., UL data) is associated with the second TRP or the second TRP identifier and / or identifier value, the UL transmission is associated with or uses a HARQ process in the second set of HARQ processes.

[0164] In some cases, the UE performs at least one of the following actions in response to the expiration of the first TAT. (i) Flush or clear the HARQ buffer belonging to or associated with the first set of HARQ processes, where (a) in some embodiments, the UE does not support retransmissions scheduled by PDCCH received with a different CORESETPoolIndex compared to the CORESETPoolIndex of the initial transmission (e.g., when the UE does not expect to receive DCI from different CORESETPoolIndices scheduling retransmissions for the same HARQ process ID), the UE performs the action. (b) In some embodiments, when the UE reports supportRetx-Diff-CoresetPool-Multi-DCI-TRP-r16, the UE performs the action. And / or (c) in some embodiments, the action refers to flushing or clearing the HARQ buffer belonging to or associated with each of the first set of HARQ processes of the first set of serving cells. (ii) Do not flush or clear the HARQ buffer belonging to or associated with the second set of HARQ processes. (iii) Do not flush or clear the HARQ buffer belonging to or associated with each of the second set of HARQ processes of the second set of serving cells. (iv) Do not flush or clear the HARQ buffer belonging to or associated with HARQ processes that are not in the first set of HARQ processes of the first and / or second serving cells. And / or (v) Do not flush or clear the HARQ buffer belonging to or associated with HARQ processes that are not in the first set of HARQ processes of the first set of serving cells and / or the second set of serving cells. In such a case, the first TAG is the STAG. In such a case, the first TA value belongs to or is associated with the STAG. In such a case, the first TAT is associated with the STAG.

[0165] Alternatively, in response to the expiration of the first TAT, the UE performs at least one of the following actions: (i) Flush or clear the HARQ buffer belonging to or associated with the second set of HARQ processes. (ii) Flush or clear the HARQ buffer belonging to or associated with each of the second set of HARQ processes of the second set of serving cells. (iii) Flush or clear the HARQ buffer belonging to or associated with HARQ processes other than the first set of HARQ processes of the first and / or second serving cells. (iv) Flush or clear the HARQ buffer belonging to or associated with HARQ processes other than the first set of HARQ processes within the first set of serving cells and / or the second set of serving cells. (v) Flush or clear all HARQ buffers of the first and / or second serving cells. (vi) Flush or clear all HARQ buffers within the first set of serving cells and / or the second set of serving cells. (vii) Flush or clear all HARQ buffers belonging to or associated with the HARQ processes of the data related to the first index of all serving cells. And / or, (viii) Flush or clear all HARQ buffers of all serving cells. In such a case, the first TAG is the PTAG. In such a case, the first TA value belongs to or is associated with the PTAG. In such a case, the first TAT is associated with the PTAG.

[0166] In some cases, in response to the expiration of the second TAT, the UE performs at least one of the following actions: (i) Flush or clear the HARQ buffer belonging to or associated with the second set of HARQ processes, where (a) in some embodiments, when the UE does not support retransmissions scheduled by PDCCH received with a different CORESETPoolIndex compared to the CORESETPoolIndex of the initial transmission (e.g., when the UE does not expect to receive DCI from different CORESETPoolIndices scheduling retransmissions for the same HARQ process ID), the UE performs the action. (b) In some embodiments, when the UE reports supportRetx-Diff-CoresetPool-Multi-DCI-TRP-r16, the UE performs the action. And / or (c) in some embodiments, the action refers to flushing or clearing the HARQ buffer belonging to or associated with each of the second set of HARQ processes of the second set of serving cells. (ii) Do not flush or clear the HARQ buffer belonging to or associated with the first set of HARQ processes. (iii) Do not flush or clear the HARQ buffer belonging to or associated with each of the first set of HARQ processes of the first set of serving cells. (iv) Do not flush or clear the HARQ buffer belonging to or associated with HARQ processes that are not of the second set of HARQ processes of the first and / or second serving cells. And / or (v) Do not flush or clear the HARQ buffer belonging to or associated with HARQ processes that are not of the second set of HARQ processes of the first set of serving cells and / or the second set of serving cells. In such a case, the second TAG is the STAG. In such a case, the second TA value may belong to or be associated with the STAG. In such a case, the second TAT is associated with the STAG.

[0167] Alternatively, in response to the expiration of the second TAT, the UE performs at least one of the following actions: (i) Flush or clear the HARQ buffer belonging to or associated with the first set of HARQ processes. (ii) Flush or clear the HARQ buffer belonging to or associated with each of the first set of HARQ processes of the first set of serving cells. (iii) Flush or clear the HARQ buffer belonging to or associated with HARQ processes that are not of the second set of HARQ processes of the first and / or second serving cells. (iv) Flush or clear the HARQ buffer belonging to or associated with HARQ processes that are not of the second set of HARQ processes within the first set of serving cells and / or the second set of serving cells. (v) Flush or clear all HARQ buffers of the first and / or second serving cells. (vi) Flush or clear all HARQ buffers of the first set of serving cells and / or the second set of serving cells. (vii) Flush or clear all HARQ buffers belonging to or associated with the HARQ processes of the data related to the second TRP, or the second TRP identifier and / or identifier value, of all serving cells. And / or, (viii) Flush or clear all HARQ buffers of all serving cells. In such a case, the second TAG is the PTAG. In such a case, the second TA value belongs to or is associated with the PTAG. In such a case, the second TAT is associated with the PTAG.

[0168] Next, referring to FIG. 8A, the UE (e.g., UE 102) implements an exemplary method 800A of operating multiple TA values under multiple TRP scenarios.

[0169] Method 800A starts at block 802. Blocks 802, 804, 806, 808, 810, and 811A are the same as blocks 602, 604, 606, 608, 610, and 611. If the UE detects that the first TAT has expired, the flow proceeds to block 812. At block 812, the UE clears the configured UL grant that is configured with and / or associated with the first TA value. If the UE detects that the second TAT has expired, the flow proceeds to block 814. At block 814, the UE clears the configured UL grant that is configured with and / or associated with the second TA value.

[0170] FIG. 8B shows an exemplary method 800B that is similar to scenario 800A shown in FIG. 8A, but method 800B differs in that it includes blocks 811B, 813, and 815.

[0171] At block 811B, the UE detects whether the first TAT and the second TAT have expired. If the UE detects that the first TAT and the second TAT have expired, the flow proceeds to block 813. At block 813, the UE performs the clear action described in block 812 and / or 814. If the UE does not detect that the first TAT and the second TAT have expired, the flow proceeds to block 815. At block 815, the UE refrains from performing the clear action described in block 812 and / or 814.

[0172] Next, referring to FIG. 9A, a UE (e.g., UE 102) implements an exemplary method 900A of operating multiple TA values under multiple TRP scenarios.

[0173] Method 900A starts at block 902. Blocks 902, 904, 906, 908, 910, and 911A are the same as blocks 602, 604, 606, 608, 610, and 611. If the UE detects that the first TAT has expired, the flow proceeds to block 912. At block 912, the UE releases the PUCCH resource and / or scheduling request resource configuration instance configured with and / or associated with the first TA value. If the UE detects that the second TAT has expired, the flow proceeds to block 914. At block 914, the UE releases the PUCCH resource and / or scheduling request resource configuration instance configured with and / or associated with the second TA value.

[0174] FIG. 9B shows an exemplary method 900B that is similar to scenario 900A shown in FIG. 9A, but method 900B differs in that it includes blocks 911B, 913, and 915.

[0175] At block 911B, the UE detects whether the first TAT and the second TAT have expired. If the UE detects that the first TAT and the second TAT have expired, the flow proceeds to block 913. At block 913, the UE performs the release action described in block 912 and / or 914. If the UE does not detect that the first TAT and the second TAT have expired, the flow proceeds to block 915. At block 815, the UE holds off on performing the release action described in block 912 and / or 914.

[0176] Next, referring to FIG. 10A, a UE (e.g., UE 102) implements an exemplary method 1000A for operating on multiple TA values under multiple TRP scenarios.

[0177] Method 1000A starts at block 1002. Blocks 1002, 1004, 1006, 1008, 1010, and 1011A are the same as blocks 602, 604, 606, 608, 610, and 611. If the UE detects that the first TAT has expired, the flow proceeds to block 1012. At block 1012, the UE releases the SRS resource configuration instance configured with and / or associated with the first TA value. If the UE detects that the second TAT has expired, the flow proceeds to block 1014. At block 1014, the UE releases the SRS resource configuration instance configured with and / or associated with the second TA value.

[0178] Figure 10B shows an exemplary method 1000B that is similar to scenario 1000A shown in Figure 10A, but method 1000B differs in that it includes blocks 1011B, 1013, and 1015.

[0179] At block 1011B, the UE detects whether the first TAT and the second TAT have expired. If the UE detects that the first TAT and the second TAT have expired, the flow proceeds to block 1013. At block 1013, the UE performs the release action described in block 1012 and / or 1014. If the UE does not detect that the first TAT and the second TAT have expired, the flow proceeds to block 1015. At block 1015, the UE holds off on performing the release action described in block 1012 and / or 1014.

[0180] Next, referring to Figure 11A, a UE (e.g., UE102) implements an exemplary method 1100A that performs operations on multiple TA values under multiple TRP scenarios.

[0181] Method 1100A starts at block 1102. Blocks 1102, 1104, 1106, 1108, 1110, and 1111A are the same as blocks 602, 604, 606, 608, 610, and 611. If the UE detects that the first TAT has expired, the flow proceeds to block 1112. At block 1112, the UE clears the PUSCH resources for semi-persistent CSI reporting that are configured with the first TA value and / or associated with the first TA value. If the UE detects that the second TAT has expired, the flow proceeds to block 1114. At block 1114, the UE clears the PUSCH resources for semi-persistent CSI reporting that are configured with the second TA value and / or associated with the second TA value.

[0182] Figure 11B shows an exemplary method 1100B that is similar to scenario 1100A shown in Figure 11A, but method 1100B differs in that it includes blocks 1111B, 1113, and 1115 described below.

[0183] At block 1111B, the UE detects whether the first TAT and the second TAT have expired. If the UE detects that the first TAT and the second TAT have expired, the flow proceeds to block 1113. At block 1113, the UE performs the clear action described in block 1112 and / or 1114. If the UE does not detect that the first TAT and the second TAT have expired, the flow proceeds to block 1115. At block 1115, the UE withholds performing the clear action described in block 1112 and / or 1114.

[0184] Similar to method 600, a more detailed description of the elements of methods 800A - 1100B is generally described above.

[0185] In some cases, in response to the expiration of the first TAT, the UE releases, clears, or suspends the configured resources, or sends an RRC notification to release the resources configured in the first set of serving cells, where the configured resources are associated with the first TA value or the first index. In such a case, the first TAG is the STAG. In such a case, the first TA value belongs to or is associated with the STAG. In such a case, the first TAT is associated with the STAG.

[0186] In some cases, in response to the expiration of the second TAT, the UE releases, clears, or suspends the configured resources, or sends an RRC notification to release the resources configured in the second set of serving cells, where in some embodiments, the configured resources are associated with the second TA value or the second index. In such a case, the second TAG is the STAG. In such a case, the second TA value belongs to or is associated with the STAG. In such a case, the second TAT is associated with the STAG.

[0187] In some cases, the configured resource is one of the following: (i) a PUCCH resource, (ii) an SRS resource, (iii) a configured downlink allocation (e.g., DL SPS), (iv) a configured uplink grant, and / or (v) a PUSCH resource, where the PUSCH resource is for semi-persistent CSI reporting.

[0188] In some cases, when the configured resource is associated with a first TA value, the configured resource follows at least one of the following: (i) the configured resource is transmitted via the first TA value, (ii) the configured resource, or the configuration for the configured resource, includes the first TA value, (iii) the configuration for the configured resource includes a first index, (iv) the configured resource is transmitted by a spatial transmission filter / parameter derived from a spatial relationship (or UL / joint TCI state or reference signal) associated with or including the first TA value, and / or (v) the configured resource is received by a spatial reception filter / parameter derived from a joint TCI state (or TCI state, QCL assumption, or reference signal) associated with or including the first TA value.

[0189] In some cases, when the configured resource is associated with a second TA value, the configured resource follows at least one of the following: (i) the configured resource is transmitted via the second TA value, (ii) the configured resource, or the configuration for the configured resource, includes the second TA value, (iii) the configuration for the configured resource includes a second index, (iv) the configured resource is transmitted by a spatial transmission filter / parameter derived from a spatial relationship (or UL / joint TCI state or reference signal) associated with or including the second TA value, and / or (v) the configured resource is received by a spatial reception filter / parameter derived from a joint TCI state (or TCI state, QCL assumption, or reference signal) associated with or including the second TA value.

[0190] In some cases, in response to the expiration of the first TAT, the UE performs at least one of the following actions: (i) releases, clears, or suspends configured resources, or sends an RRC notification to release, clear, or suspend the configured resources associated with the first TRP / TAG / TAT / TA value or the first index in all serving cells, and / or (ii) releases, clears, or suspends configured resources, or sends an RRC notification to release, clear, or suspend the configured resources in all serving cells. In such a case, the first TAG is the PTAG. In such a case, the first TA value belongs to or is associated with the PTAG. In such a case, the first TAT is associated with the PTAG.

[0191] In some cases, in response to the expiration of the second TAT, the UE performs at least one of the following actions: (i) releases, clears, or suspends configured resources, or sends an RRC notification to release, clear, or suspend the configured resources associated with the second TRP / TAG / TAT / TA value or the second index in all serving cells, and / or (ii) releases, clears, or suspends configured resources, or sends an RRC notification to release, clear, or suspend the configured resources in all serving cells. In such a case, the second TAG is the PTAG. In such a case, the second TA value belongs to or is associated with the PTAG. In such a case, the second TAT is associated with the PTAG.

[0192] In some cases, in response to the expiration of the first TAT, the UE maintains, holds, or otherwise stores the first TA value. In such a case, the first TAG is the STAG. In such a case, the first TA value belongs to or is associated with the STAG. In such a case, the first TAT is associated with the STAG.

[0193] Alternatively, in response to the expiration of the first TAT, the UE performs at least one of the following actions: (i) maintaining, holding, or otherwise storing all indicated or derived TA values associated with the first TRP / TAG / TAT / TA values or the first index across all TAGs, (ii) maintaining, holding, or otherwise storing a second TA value, and / or (iii) maintaining, holding, or otherwise storing all indicated or derived TA values across all TAGs. In such a case, the first TAG is the PTAG. In such a case, the first TA value belongs to or is associated with the PTAG. In such a case, the first TAT is associated with the PTAG.

[0194] In some cases, in response to the expiration of the second TAT, the UE maintains, holds, or stores the second TA value. In such a case, the second TAG is the STAG. In such a case, the second TA value belongs to or is associated with the STAG. In such a case, the second TAT is associated with the STAG.

[0195] Alternatively, in response to the expiration of the second TAT, the UE performs at least one of the following actions: (i) maintaining, holding, or storing all indicated or derived TA values associated with the second TRP / TAG / TAT / TA values or the second index across all TAGs, (ii) maintaining, holding, or storing the first TA value, and / or (iii) maintaining, holding, or storing all indicated or derived TA values across all TAGs. In such a case, the second TAG may be the PTAG. In such a case, the second TA value may belong to or be associated with the PTAG. In such a case, the second TAT may be associated with the PTAG.

[0196] Next, referring to FIG. 12A, a UE (e.g., UE 102) implements an exemplary method 1200A of performing operations on a plurality of TA values under a plurality of TRP scenarios.

[0197] Method 1200A starts at block 1202. Blocks 1202, 1204, 1206, 1208, 1210, and 1211 are similar to blocks 602, 604, 606, 608, 610, and 611. If the UE detects that the first TAT has expired, the flow proceeds to block 1212A. At block 1212A, the UE triggers a CBRA procedure associated with the first TA value with the base station. If the UE detects that the second TAT has expired, the flow proceeds to block 1214A. At block 1214A, the UE triggers a CBRA procedure associated with the second TA value with the base station.

[0198] FIG. 12B shows an exemplary method 1200B that is similar to scenario 1200A shown in FIG. 12A, but method 1200B differs in that it includes blocks 1212B and 1214B.

[0199] If the UE detects that the first TAT has expired, the flow proceeds to block 1212B. At block 1212B, the UE transmits a first MAC CE indicating the expiration of the first TA value to the base station. If the UE detects that the second TAT has expired, the flow proceeds to block 1214B. At block 1214B, the UE transmits a second MAC CE indicating the expiration of the second TA value to the base station.

[0200] In some embodiments, the first MAC CE and the second MAC CE have the same MAC CE format. In some embodiments, the UE transmits, at block 1212B, a MAC PDU including the sub-header of the first MAC CE and the first MAC CE to the base station. In some embodiments, the UE transmits, at block 1214B, a MAC PDU including the sub-header of the second MAC CE and the second MAC CE to the base station.

[0201] In some embodiments, the UE includes in the first MAC CE the ID of the first TA value or the ID of the first TAG associated with the first TA value. In some embodiments, the UE includes in the second MAC CE the ID of the second TA value or the ID of the second TAG associated with the second TA value.

[0202] FIG. 12C shows an exemplary method 1200C that is similar to scenario 1200A shown in FIG. 12A, but method 1200C is different in that it includes blocks 1212C and 1214C.

[0203] If the UE detects that the first TAT has expired, the flow proceeds to block 1212C. In block 1212C, the UE transmits to the base station a first RRC message indicating the expiration of the first TA value. If the UE detects that the second TAT has expired, the flow proceeds to block 1214C. In block 1214C, the UE transmits to the base station a second RRC message indicating the expiration of the second TA value.

[0204] In some embodiments, the first RRC message and the second RRC message have the same RRC message format. For example, the first RRC message and the second RRC message are UE assistance information messages (e.g., UE Assistance Information messages).

[0205] In some embodiments, the UE includes in the first RRC message the ID of the first TA value or the ID of the first TAG associated with the first TA value. In some embodiments, the UE includes in the second RRC message the ID of the second TA value or the ID of the second TAG associated with the second TA value.

[0206] FIG. 12D shows an exemplary method 1200D that is similar to scenario 1200A shown in FIG. 12A, but method 1200D is different in that it includes blocks 1212D and 1214D.

[0207] When the UE detects that the first TAT has expired, the flow proceeds to block 1212D. In block 1212D, the UE transmits a first PUCCH transmission indicating the expiration of the first TA value to the base station. When the UE detects that the second TAT has expired, the flow proceeds to block 1214D. In block 1214D, the UE transmits a second PUCCH transmission indicating the expiration of the second TA value to the base station.

[0208] In some embodiments, the UE includes in the first PUCCH transmission the ID of the first TA value or the ID of the first TAG associated with the first TA value. In some embodiments, the UE includes in the second PUCCH transmission the ID of the second TA value or the ID of the second TAG associated with the second TA value.

[0209] FIG. 12E shows an exemplary method 1200E that is similar to scenario 1200A shown in FIG. 12A, but method 1200E differs in that it includes blocks 1211E and 1216.

[0210] In block 1211E, the UE detects whether the first TAT has expired, whether the second TAT has expired, and whether both the first TAT and the second TAT have expired. When the UE detects that the first TAT has expired, the UE performs the actions described in block 1212B, 1212C, or 1212D. When the UE detects that the second TAT has expired, the UE performs the actions described in block 1214B, 1214C, or 1214D. When the UE detects that both the first TAT and the second TAT have expired, the flow proceeds to block 1216. In block 1216, the UE triggers a CBRA procedure with the base station.

[0211] Similar to method 600, a more detailed description of the elements of methods 1200A - 1200E is generally detailed above.

[0212] In some cases, the UE performs an action when at least one of the following is satisfied or achieved: (i) the first TAT expires; (ii) the UE has UL data or a UL channel / RS associated with the first index; (iii) the UE has UL data or a UL channel / RS intended for or associated with the first TRP for transmission; and / or (iv) the UE has UL data or a UL channel / RS for transmission via the first TA value. In some such embodiments, the action that the UE then performs is at least one of the following actions: (i) trigger or execute a contention-based or contention-free RA procedure associated with the first index; (ii) trigger or execute a contention-based or contention-free RA procedure intended for the first TRP, the first TAG, the first TAT, or the first TA value; and / or (iii) send the first MAC-CE to the NW, where the second TAT has not expired.

[0213] In some cases, the UE performs an action when at least one of the following is satisfied or achieved: (i) the second TAT expires; (ii) the UE has UL data or a UL channel / RS associated with the second index; (iii) the UE has UL data or a UL channel / RS intended for or associated with the second TRP for transmission; and / or (iv) the UE has UL data or a UL channel / RS for transmission via the second TA value. In some such embodiments, the action that the UE then performs is at least one of the following actions: (i) trigger or execute a contention-based or contention-free RA procedure associated with the second index; (ii) trigger or execute a contention-based or contention-free RA procedure intended for the second TRP, the second TAG, the second TAT, or the second TA value; and / or (iii) send the second MAC-CE to the NW, where the first TAT has not expired.

[0214] In some cases, when the RA procedure is associated with or intended for at least one of (a) a first index, and / or (b) a first TRP / TAG / TA value / TAT, at least one of the following applies. (i) The MSG 0 or PDCCH order (e.g., received by the UE from the base station) for the RA procedure indicates or is associated with the first index, where in some embodiments, the RA procedure is a non - competing RA procedure, (ii) The MSG 1 or MSG A (e.g., transmitted by the UE to the base station) for the RA procedure indicates or is associated with the first index, (iii) The MSG 2 or MSG B (e.g., received by the UE from the base station) for the RA procedure indicates or is associated with the first index, and / or (iv) The MSG 3 (e.g., transmitted by the UE to the base station) or the MSG 4 (e.g., received by the UE from the base station) for the RA procedure indicates or is associated with the first index.

[0215] In some cases, when the RA procedure is associated with or intended for at least one of (a) a second index, and / or (b) a second TRP / TAG / TA value / TAT, at least one of the following applies. (i) The MSG 0 or PDCCH order (e.g., received by the base station from the UE) for the RA procedure indicates or is associated with the second index, where in some embodiments, the RA procedure is a non - competing RA procedure, (ii) The MSG 2 or MSG B (e.g., transmitted by the UE to the base station) for the RA procedure indicates or is associated with the second index, (iii) The MSG 2 or MSG B (e.g., received by the UE from the base station) for the RA procedure indicates or is associated with the second index, and / or (iv) The MSG 3 (e.g., transmitted by the UE to the base station) or the MSG 4 (e.g., received by the UE from the base station) for the RA procedure indicates or is associated with the second index.

[0216] In some embodiments, the first and / or second MAC-CE indicates at least one of the following, which are (i) a first index or a second index, (ii) which TA value or TAG has expired, and / or (iii) an estimated TA offset or difference.

[0217] In some cases, when the base station receives the first MAC-CE, the base station sends a MSG 0 or PDCCH order to the UE. In further embodiments, when the NW receives the first MAC-CE, the NW sends a MSG 0 or PDCCH order to the UE, where (i) the MSG 0 or PDCCH order indicates or is associated with the first index, and / or (ii) the MSG 0 or PDCCH order indicates or is associated with the first index if the first MAC-CE indicates the first index.

[0218] In some cases, when the base station receives the second MAC-CE, the base station sends a MSG 0 or PDCCH order to the UE. In further embodiments, when the NW receives the first MAC-CE, the NW sends a MSG 0 or PDCCH order to the UE, where (i) the MSG 0 or PDCCH order indicates or is associated with the second index, and / or (ii) the MSG 0 or PDCCH order indicates or is associated with the second index if the first MAC-CE indicates the first index.

[0219] In some embodiments, the MAC-CE of the first MAC-CE and / or the second MAC-CE refers to or is replaced by a TA expiration indication MAC-CE or a TA expiration report MAC-CE. In some embodiments, the first MAC-CE and the second MAC-CE are the same MAC-CE. Alternatively, the first MAC-CE and the second MAC-CE are different MAC-CEs.

[0220] Next, referring to FIG. 13, a UE (e.g., UE 102) implements an exemplary method 1300 of performing operations on a plurality of TA values under a plurality of TRP scenarios.

[0221] Method 1300 begins at block 1302. Blocks 1302, 1304, and 1306 are similar to blocks 602, 604, and 606. At block 1308, the UE starts or resumes a single TAT to maintain a first UL synchronization and a second UL synchronization with the base station. In some embodiments, the single TAT is the third TAT described above. At block 1310, the UE detects or determines whether the single TAT has expired. At block 1312, in response to the expiration of the single TAT, the UE performs the actions described at 612 / 614, 712B, 812 / 814, 912 / 914, 1012 / 1014, 1112 / 1114, 1212A / 1214A, 1212B / 1214B, 1212C / 1212C, 1212D / 1214D, and / or 1216.

[0222] In some embodiments, the UE starts or resumes a single TAT and, when it receives a first TA value, a second TA value, or both the first TA value and the second TA value (e.g., upon receipt, in response to receipt, or after receipt), maintains a first UL synchronization and a second UL synchronization with the UE.

[0223] Similar to method 600, a more detailed description of the elements of method 1300 is generally detailed above.

[0224] In some cases (including method 1300), the UE maintains one TAT (e.g., the third TAT) for the first TA value and the second TA value. In some embodiments, the UE maintains one TAT (e.g., the third TAT) for the first TA value and the second TA value, and the third TAT is used to determine whether the first TA value and / or the second TA value has expired.

[0225] In some cases, the UE receives a third MAC-CE, and the third MAC-CE indicates or updates the first TA value and the second TA value simultaneously. In some embodiments, when the UE receives the third MAC-CE, the UE expects that the third MAC-CE indicates or updates the first TA value and the second TA value simultaneously. In some embodiments, when the UE maintains one TAT (e.g., a third TAT) for the first TA value and the second TA value, the UE expects that when received, the third MAC-CE updates the first TA value and the second TAT value simultaneously.

[0226] In some embodiments, when the UE receives the third MAC-CE and the third MAC-CE does not indicate or update the first TA value and the second TA value simultaneously, the UE ignores, discards, or otherwise does not use the third MAC-CE. In some embodiments, when the UE maintains one TAT (e.g., a third TAT) for the first TA value and the second TA value, when the UE receives the third MAC-CE and the third MAC-CE does not indicate or update the first TA value and the second TA value simultaneously, the UE ignores, discards, or otherwise does not use the third MAC-CE.

[0227] In some cases, the base station maintains one TAT (e.g., a third TAT) for the first TA value and the second TA value. In some embodiments, the base station maintains one TAT (e.g., a third TAT) for the first TA value and the second TA value, where the third TAT is used to determine whether the first TA value and / or the second TA value has expired.

[0228] In some cases, the base station transmits a third MAC-CE, and the third MAC-CE indicates or updates the first TA value and the second TA value simultaneously. In some embodiments, when the base station transmits the third MAC-CE, the base station may need to indicate or update the first TA value and the second TA value simultaneously. In some such embodiments, the base station cannot use the third MAC-CE and indicates or updates only one of the first TA value or the second TA value. In some embodiments, when the base station maintains one TAT (e.g., a third TAT) for the first TA value and the second TA value, the base station may be required to indicate or update the first TA value and the second TAT value simultaneously. In some embodiments, when the base station maintains one TAT (e.g., a third TAT) for the first TA value and the second TA value and the base station transmits the third MAC-CE, the base station may be required to indicate or update the first TA value and the second TA value simultaneously in the third MAC-CE.

[0229] In some embodiments, when the UE maintains one TAT (e.g., a third TAT) for the first TA value and the second TA value, the first TA value and the second TA value belong to or are associated with a TAG (e.g., a third TAG). In some embodiments, when the UE maintains one TAT (e.g., a third TAT) for the first TA value and the second TA value, the first TA value and the second TA value belong to or are associated with different TAGs (e.g., a first TAG and a second TAG), respectively.

[0230] In some embodiments, the third MAC-CE is one of the following, which include (i) an (enhanced) timing advance command MAC CE, (ii) an (enhanced) timing advance command in the RAR response or in the MAC payload for the RAR response, or (iii) an (enhanced) absolute timing advance command in response to an MSGA transmission including a C-RNTI MAC CE.

[0231] In some embodiments, the third MAC-CE is also used when and / or while the UE is configured to maintain two TATs (e.g., a first TAT and a second TAT) in at least one serving cell. In some embodiments, the third MAC-CE is used to indicate or update a first TA value and / or a second TA value, where (i) the first TA value and the second TA value are, in some embodiments, indicated or updated simultaneously, (ii) the first TA value and the second TA value are, in some embodiments, indicated or updated separately (e.g., at different times), and / or (iii) the first TAT and the second TAT values belong to or are associated with different TATs (e.g., a first TAT and a second TAT).

[0232] Referring now to FIG. 14, a UE (e.g., UE 102) implements an exemplary method 1400 for operating on multiple TA values under multiple TRP scenarios.

[0233] Method 1400 begins at block 1402. Blocks 1402 and 1404 are similar to blocks 602 and 604. At block 1406, the UE receives a first TA value from the base station. At block 1408, the UE uses the first TA value to transmit a UL transmission to the base station. At block 1410, when the UE receives the first TA value, it starts or resumes a first TAT to maintain a first UL synchronization with the base station. At block 1412, the UE receives a MAC CE containing a delta value from the base station. At block 1414, the UE derives a second TA value using the first TA value and the delta value. At block 1416, in some embodiments, when the UE receives the delta value or derives the second TA value, it starts or resumes a second TAT to maintain a second UL synchronization with the base station. At block 1418, the UE uses the second TA value to transmit a UL transmission to the base station. At block 1420, when the first TAT expires, the UE considers or determines whether the second TAT has expired.

[0234] Similar to method 600, a more detailed description of the elements of method 1400 is generally detailed above.

[0235] In some cases, the UE derives a second TA value. In some embodiments, the exact value of the second TA value is not explicitly indicated or signaled to the UE (e.g., MAC-CE or DCI) by the base station. In some embodiments, the exact value of the first TA value is explicitly indicated or signaled by the base station (e.g., MAC-CE or DCI).

[0236] In some embodiments, when the UE derives a second TA value, there is no TAT (e.g., a dedicated TAT) for or associated with the second TA value. In some embodiments, when the UE derives a second TA value, there is no TAG (e.g., a dedicated TAG) for or associated with the second TA value.

[0237] In some cases, the UE receives a delta value. In some embodiments, the second TA value is derived by using the delta value. In some embodiments, the second TA value is derived by using the first TA value and the delta value. In some embodiments, the second TA value is the sum of the first TA value and the delta value. In some embodiments, the possible value range of the value obtained by adding the first TA value to the delta value is the same as or a subset of that of the first TA value. In some embodiments, the NW indicates or signals the delta value. In some such embodiments, the NW indicates or signals the delta value via one of RRC, MAC-CE, or DCI.

[0238] In some embodiments, the delta value is indicated or updated by a fourth MAC-CE. The fourth MAC-CE is, in some embodiments, the MAC-CE described in method 1400. In some embodiments, the fourth MAC-CE can indicate or update a first TA value. In some embodiments or alternatively, the fourth MAC-CE cannot indicate or update a first TA value.

[0239] In some embodiments, if the UE receives a fourth MAC-CE and the fourth MAC-CE does not indicate or update a delta value, the currently applied delta value continues to be used or is not changed. In some embodiments, (i) if the fourth MAC-CE can indicate or update a delta value and a first TA value, and (ii) if the UE receives a fourth MAC-CE that does not indicate or update a delta value, the currently applied delta value is used.

[0240] In some embodiments, the fourth MAC-CE includes a bit or field indicating whether the delta value is indicated or updated by the fourth MAC-CE. In some embodiments, the fourth MAC-CE includes a bit or field indicating whether the delta value is present or included in the fourth MAC-CE.

[0241] In some embodiments, when the first TAT has expired, the UE determines whether the second TA value has expired or is due. In some embodiments, when the first TAT has expired, the UE determines whether the delta value has expired or is due. In further embodiments, the base station configures or indicates for the UE a special timer for determining whether the delta value has expired / due or is valid. In some embodiments, the UE holds a special timer for determining whether the delta value has expired / due or is valid. In some embodiments, when the special timer has expired, the UE determines whether the second TA value has expired or is due.

[0242] Note that throughout this disclosure, "the TA value expires" can refer to at least one of the following: (i) the TA value is not synchronized, (ii) the TA value has expired, and / or (iii) the TA value is uplink time-aligned.

[0243] Note that throughout this disclosure, an adjacent cell can refer to or be replaced by at least one of the following: (i) a non-serving cell, (ii) a cell having a PCI different from the PCI of the serving cell, and / or (iii) a TRP associated with a PCI different from the PCI of the serving cell.

[0244] Note that throughout this disclosure, a joint TCI state can refer to or be replaced by at least one of the following: (i) a beam applicable to both DL transmission and UL transmission (e.g., a DL or UL channel, a DL or UL RS, etc.), (ii) a spatial filter for transmission and / or reception, (iii) a spatial parameter for transmission and / or reception, (iv) a spatial relationship for transmission and / or reception, and / or (v) a spatial assumption for transmission and / or reception.

[0245] Note that throughout this disclosure, the joint TCI state can refer to, or be replaced by, a common TCI state or a unified TCI state.

[0246] Note that throughout this specification, the UL TCI state can refer to, or be replaced by, at least one of the following: (i) a UL beam, (ii) a spatial relationship, (iii) a spatial transmit filter, (iv) a transmit precoder, (v) a spatial parameter, and / or (vi) a spatial relationship.

[0247] Note that throughout this disclosure, the DL TCI state can refer to, or be replaced by, at least one of the following: (i) TCI applicable to a DL channel or RS, (ii) TCI associated with quasi-collocation (QCL) type D, (iii) a QCL assumption, (iv) a DL beam, (v) a spatial receive filter, (vi) a spatial parameter, (vii) a spatial relationship, and / or (viii) a spatial assumption.

[0248] Note that throughout this disclosure, a TCI pool (e.g., a joint TCI pool, a UL TCI pool, a DL TCI pool) can refer to, or represent, a (RRC) configuration or list, which can include or contain one or more TCIs (indices). Note that throughout this disclosure, "TCI" can also be referred to as, or replaced by, "TCI state". Note that throughout this disclosure, "TCI pool" can also be referred to as, or replaced by, "TCI state pool".

[0249] Throughout the present disclosure, it should be noted that a UE may have one or more of the following attributes or behaviors. The following attributes or behaviors of the UE may also mean related attributes or behaviors of the base station. (i) The UE is composed of and / or served by base stations within the serving cell. (ii) The UE is configured to communicate with base stations within the serving cell. (iii) The UE is composed of one or more serving cells by the base station, and the base station may include the serving cell. (iv) The UE is activated or indicated by the base station to activate one or more serving cells, and this base station may include the serving cell. (v) The UE configures and / or indicates one or more BWPs by the base station. The UE instructs and / or configures the BWP within the serving cell by the base station. (a) In some embodiments, the BWP is activated as the active BWP. (b) In some embodiments, the BWP refers to the active BWP. (c) In some embodiments, the BWP is an active DL BWP. (d) In some embodiments, the BWP is an active UL BWP. (e) In some embodiments, the BWP is the initial BWP. (f) In some embodiments, the BWP is the default BWP. (g) In some embodiments, the BWP is the dormant BWP. (vi) The UE is in any of the RRC_CONNECTED state, the RRC_INACTIVE state, or the RRC_IDLE state.

[0250] Throughout the present disclosure, it should be noted that the expression "X / Y" may include the meaning of "X or Y". Throughout the present disclosure, it should be noted that the expression "X / Y" may include the meaning of "X and Y". Throughout the present disclosure, it should be noted that the expression "X / Y" may include the meaning of "X and / or Y". Throughout the present disclosure, it should be noted that the expression "(A)B" or "B(A)" may include the concept of "only B". Throughout the present disclosure, it should be noted that the expression "(A)B" or "B(A)" may include the concept of "A + B" or "B + A".

[0251] Throughout the present disclosure, note that a panel may mean an antenna (port) group or an antenna (port) set. There can be multiple DL / UL beams associated with one panel. When one transmitting node (UE or base station) performs transmission via a panel, transmission can be performed using only one beam associated with the panel. For example, in the case of a transmitter including multiple panels, such as two panels, it may happen that transmission is performed using two beams respectively associated with the two panels.

[0252] Throughout the present disclosure, note that a TRP identifier may mean a (candidate) value of the TRP identifier or may be referred to as a (candidate) value. The first TRP identifier may be the first candidate value of the TRP identifier or the first TRP identifier value. The second TRP identifier may be the second candidate value of the TRP identifier or the second TRP identifier value.

[0253] Throughout the present disclosure, note that a panel identifier may mean a (candidate) value of the panel identifier or may be referred to as a (candidate) value. The first panel identifier may be the first candidate value of the panel identifier or the first panel identifier value. The second panel identifier may be the second candidate value of the panel identifier or the second panel identifier value.

[0254] Throughout the present disclosure, note that a TCI field means or can indicate a field used, applied, or diverted to indicate one or more TCI states.

[0255] Throughout this disclosure, it should be noted that "joint mode" or "joint TCI state mode" may mean at least one of the following: (i) The indicated TCI state in the TCI field or DCI format refers to / maps to one of the joint TCI state pool, DL TCI state pool, or UL TCI state pool. And / or (ii) The beam indication or the indicated TCI state is applied to both UL transmission and / or DL reception.

[0256] Throughout this disclosure, it should be noted that "separate mode" or "separate TCI state mode" may mean at least one of the following: (i) The indicated TCI state in the TCI field or DCI format refers to / maps to one of the joint TCI state pool, DL TCI state pool, or UL TCI state pool. And / or (ii) The beam indication or the indicated TCI state is applied to either UL transmission (only) or DL reception (only).

[0257] Throughout this disclosure, it should be noted that "UL mode" or "UL-only TCI state mode" may mean at least one of the following: (i) The indicated TCI state in the TCI field or DCI format refers to / maps to the UL TCI state pool (joint TCI state pool). And / or (ii) The beam indication or the indicated TCI state is applied to UL transmission (only).

[0258] Throughout this disclosure, it should be noted that "DL mode" or "DL-only TCI state mode" may mean at least one of the following: (i) The indicated TCI state in the TCI field or DCI format refers to / maps to the DL TCI state pool (joint TCI state pool). And / or (ii) The beam indication or the indicated TCI state is applied to DL reception (only).

[0259] Throughout this disclosure, when a procedure or description is related to a serving cell, it should be noted that it may mean that the procedure or description is related to the active (DL / UL) BWP of the serving cell.

[0260] Throughout this disclosure, it should be noted that a "TA timer" or "TAT" can also be referred to as, or replaced by, a "TA alignment timer".

[0261] It should be noted that some or all of the foregoing or subsequent embodiments can be concatenated, combined, or formed as a new or alternative embodiment.

[0262] It should be noted that the foregoing or subsequent embodiments can be used (but not limited to) to solve at least the problems or scenarios mentioned in this disclosure.

[0263] The following additional considerations may apply to the foregoing or subsequent descriptions.

[0264] It should be noted that any two or more of the foregoing or following paragraphs, (sub) items, points, actions, or claims described in each method / embodiment / aspect can be logically, reasonably, and appropriately combined to form a specific method.

[0265] It should be noted that any sentence, paragraph, (sub) item, point, action, or claim described in each of the foregoing or following methods / embodiments / aspects can be implemented independently and separately to form a specific method. Dependencies such as "based on", "more specifically", "here" in the following methods / embodiments / aspects are only one possible embodiment and do not limit a specific method.

[0266] Note that some or all of the following terms and assumptions may be used below. (i) Base Station (BS): A network central unit within NR, or a network node, which is used to control one or more TRPs associated with one or more cells. Communication between the base station and the TRP(s) is performed via the fronthaul. The base station can be called a Central Unit (CU), eNB, gNB, or NodeB. (ii) Transmission and Reception Point (TRP): The transmission and reception point provides network coverage and communicates directly with the UE. The TRP may be called a Distributed Unit (DU) or a network node. (iii) Cell: A cell is composed of one or more associated TRPs (i.e., the coverage of a cell is composed of the coverage of all associated TRP(s)). One cell is controlled by one base station. A cell may be called a TRP Group (TRPG). (iv) Serving Beam: The serving beam for the UE is a beam generated by a network node (e.g., a TRP), and the network node is configured to be used for communicating with the UE (e.g., for transmission and / or reception). (v) Candidate Beam: The candidate beam for the UE is a candidate for the serving beam. The serving beam may or may not be a candidate beam.

[0267] A user device (e.g., UE102) on which the technology of the present disclosure can be implemented can be any suitable device capable of wireless communication, such as a smartphone, a tablet computer, a laptop computer, a mobile game console, a point-of-sale (POS) terminal, a health management device, a drone, a camera, a media streaming dongle or other personal media device, a wearable device such as a smartwatch, a wireless hotspot, a femtocell, or a broadband router. Further, the user device may, in some cases, be embedded in an electronic system such as a vehicle head unit or an advanced driver assistance system (ADAS). Still further, the user device can operate as an Internet of Things (IoT) device or a mobile Internet device (MID). Depending on the type, the user device can include one or more general-purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, and the like.

[0268] Certain embodiments are described in this disclosure as including logic or several components or modules. A module can be a software module (e.g., code stored in a non-transitory machine-readable medium) or a hardware module. A hardware module is a tangible unit capable of performing a particular operation and can be configured or arranged in a particular manner. A hardware module can include dedicated circuitry or logic that is permanently configured (e.g., as a special-purpose processor such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC)) to perform a particular operation. A hardware module can also include programmable logic or circuitry (e.g., included within a general-purpose processor or other programmable processor) that is temporarily configured by software to perform a particular operation. The decision to implement a hardware module within dedicated and permanently configured circuitry or within temporarily configured circuitry (e.g., configured by software) can be left to cost and time considerations.

[0269] When implemented in software, the technology can be provided as part of an operating system, a library used by multiple applications, a particular software application, etc. The software is executable by one or more general-purpose processors or one or more special-purpose processors.

Claims

1. A method for managing synchronization, the method being implemented in a user equipment (UE), receiving, from a radio access network (RAN), a configuration including a first timing advance (TA) value and a second TA value; operating a first TA timer (TAT) corresponding to the first TA value to manage synchronization between a first uplink (UL) transmission and a first receiver in the RAN; operating a second TAT corresponding to the second TA value to manage synchronization between a second UL transmission and a second receiver in the RAN; stopping the first UL transmission in response to expiration of the first TAT; stopping the second UL transmission in response to expiration of the second TAT; The method, comprising the above.

2. The first receiver is a first transmission and reception point (TRP) of a node in the RAN, The second receiver is a second TRP of the node, The method according to claim 1, wherein the UE is configured to communicate with the first TRP and the second TRP in a multi-TRP (M-TRP) mode.

3. The method according to claim 2, further comprising continuing the second UL transmission to the second TRP after the first TAT expires and before the second TAT expires.

4. The method according to claim 3, wherein continuing the second UL transmission includes continuing to receive scheduling of the second UL transmission from the RAN.

5. The first TRP is associated with a first TA group (TAG), The method according to any one of claims 2 to 4, wherein the second TRP is associated with a second TAG.

6. The first TA value is associated with a first TCI state, The method according to claim 5, wherein the second TA value is associated with a second TCI state.

7. The first receiver operates in a serving cell, The method according to claim 1, wherein the second receiver operates in a non-serving cell.

8. Operating the first TAT includes starting or restarting the first TAT in response to receiving the first TA value, Operating the second TAT includes starting or restarting the second TAT in response to receiving the second TA value, The method according to any one of claims 1 to 7.

9. The method according to any one of claims 1 to 8, further comprising receiving an indication from the RAN that the use of a plurality of TA values in the serving cell is valid.

10. Receiving the first TA value comprises: transmitting a random access preamble to the first receiver; receiving the first TA value from the first receiver in response to the random access preamble; The method according to any one of claims 1 to 9.

11. Receiving the first TA value comprises: receiving a media access control (MAC) control element (CE) including the first TA value. The method according to any one of claims 1 to 9.

12. Receiving the first TA value comprises: receiving a MAC protocol data unit (PDU) including the first TA value. The method according to any one of claims 1 to 11.

13. Transmitting to the RAN a first expiration indication that the first TAT has expired in response to expiration of the first TAT; Transmitting to the RAN a second expiration indication that the second TAT has expired in response to expiration of the second TAT; The method according to any one of claims 1 to 12, further comprising.

14. The method according to claim 13, wherein each of the first expiration indication and the second expiration indication is included in a respective MAC CE.

15. A transceiver; Processing hardware configured to implement the method according to any one of claims 1 to 14; A user equipment (UE) comprising.

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