Managing communications over multiple transmission and / or reception points

Abstract

A method of multiple transmission and reception point (M-TRP) communication in a user equipment (UE) comprises receiving (596), from a radio access network (RAN) node equipped with a first transmission and reception point (TRP) and a second TRP, a configuration for initiating a random access procedure, the configuration comprising an indication of a random access preamble associated with the second TRP of the RAN node; sending (566) a random access preamble to the second TRP; and receiving (573), from the first TRP, a random access response comprising a timing advance (TA) value associated with the second TRP.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority and filing date to Provisional U.S. Patent Application No. 63 / 393,820, filed on July 29, 2022, entitled “MANAGING COMMUNICATION OVER MULTIPLE TRANSMIT AND / OR RECEIVE POINTS” and Provisional U.S. Patent Application No. 63 / 393,560, filed on July 29, 2022, entitled “ENABLING COMMUNICATION OVER MULTIPLE TRANSMIT AND / OR RECEIVE POINTS”. The entire contents of the provisional applications are hereby expressly incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to wireless communications, and more particularly to managing communications between a user equipment (UE) and a base station through multiple transmission and / or reception points (TRPs). Background Art

[0004] This background description is provided for the purpose of generally presenting the context of the present disclosure. The work of the presently named inventors is neither explicitly nor implicitly admitted to be prior art to the present disclosure to the extent that it is described in this background section and in all aspects that may not have otherwise qualified as prior art at the time of filing.

[0005] Typically, a base station operating a cellular radio access network (RAN) uses a certain radio access technology (RAT) and multiple layers of a protocol stack to communicate with a user equipment (UE). For example, the physical layer (PHY) of the RAT provides a transport channel to the medium access control (MAC) sublayer, which in turn provides a logical channel to the radio link control (RLC) sublayer, and the RLC sublayer in turn provides data transfer services to the packet data convergence protocol (PDCP) sublayer. The radio resource control (RRC) sublayer is arranged above the PDCP sublayer.

[0006] Currently, there are technologies that support the following: Multi-TRP (mTRP) operation for Physical Downlink Shared Channel (PDSCH), Physical Downlink Control Channel (PDCCH), Physical Uplink Shared Channel (PUSCH), and Physical Uplink Control Channel (PUCCH) transmissions. In particular, a maximum of two TRPs are currently supported in mTRP operation.

[0007] In addition, mTRP PDSCH transmission currently supports two different mechanisms: single downlink control information (DCI) and multiple DCI (multi-DCI). Further, mTRP PDSCH transmission is extended to inter-cell operation. In inter-cell operation, the gNB can configure a synchronization signal block (SSB) associated with a physical cell identity (PCI) for the UE, which is different from the PCI of the serving cell called the additional PCI. The gNB can configure up to seven different additional PCIs for the UE, and only one of the additional PCIs is activated for inter-cell mTRP operation. The additional PCI can be associated with one or more transmission configuration indication (TCI) states, and the gNB can dynamically schedule PDSCH transmission from any TRP by indicating the TCI in the DCI and / or indicating a specific TCI state. In addition, mTRP PDCCH transmission, PUSCH transmission, and PUCCH transmission are supported for both intra-cell operation and inter-cell operation.

[0008] The mTRP operation of PUSCH transmission and PUCCH utilizes synchronized transmission from / to two TRPs for UEs at different locations within the coverage of two TRPs. However, in some deployment scenarios (e.g., the two TRPs belong to different cells, or the distance between the two TRPs is large), the transmission from / to the two TRPs is not always synchronized for UEs at different locations within the coverage of the two TRPs. Methods for supporting mTRP operation with asynchronous TRPs remain to be resolved. Summary of the invention

[0009] An example embodiment of the technology disclosed herein is a method for multiple transmission and reception point (M-TRP) communication in a user equipment (UE), the method comprising: receiving a configuration for initiating a random access procedure from a radio access network (RAN) node equipped with a first transmission and reception point (TRP) and a second TRP, the configuration comprising an indication of a random access preamble associated with the second TRP of the RAN node; sending the random access preamble to the second TRP; and receiving a random access response from the first TRP comprising a timing advance (TA) value associated with the second TRP.

[0010] Another example embodiment of these technologies is a method of multiple transmission and reception point (M-TRP) communication in a radio access network (RAN) node, the method comprising: sending a configuration for initiating a random access procedure to a user equipment (UE), the configuration including an indication of a random access preamble associated with a second TRP of the RAN node; receiving the random access preamble via the second TRP of the RAN node; and sending a random access response including a timing advance (TA) value associated with the second TRP via a first TRP of the RAN node.

[0011] Another example embodiment of the techniques is an apparatus comprising: a transceiver for communicating via a radio interface; and processing hardware configured to implement one of the methods described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1A is a block diagram of an example wireless communication system in which a radio access network (RAN) and / or user equipment (UE) may implement the techniques of this disclosure;

[0013] Figure 1B Yes, you can Figure 1A A block diagram of an example base station operating in a RAN of FIG. 1 , the base station comprising a central unit (CU) and a distributed unit (DU);

[0014] Figure 2A is a block diagram of an example protocol stack, according to which, Figure 1A The UE can be connected with Figure 1A Communicate with the RAN;

[0015] Figure 2B is a block diagram of an example protocol stack, according to which, Figure 1A The UE can be connected with Figure 1A or Figure 1B The DU and CU of the base station communicate;

[0016] Figure 3A yes Figure 2A and / or Figure 2B A block diagram of the detailed structure of the various sub-layers of the protocol stack depicted in, the protocol stack including scheduling and / or priority handling functions;

[0017] Figure 3B It is a block diagram of the detailed structure of the various sublayers of the protocol stack, and Figure 3A Similar, but in this protocol stack, the structure includes a logical channel prioritization function;

[0018] Figure 4A is a block diagram of a HARQ entity including multiple HARQ processes and communicating with transport channels to multiple TRPs;

[0019] Figure 4B is with Figure 4A A block diagram of a HARQ entity similar to that of FIG. 1 , but in this block diagram, the HARQ entity includes multiple HARQ process groups associated with multiple transport channels to multiple TRPs;

[0020] Figure 4C is with Figure 4A A block diagram of a HARQ entity similar to that of FIG. 1 , but in this block diagram, the HARQ entity communicates with a single TRP;

[0021] Figure 5A is a message passing diagram of an example scenario in which a UE synchronizes with a first TRP and / or a second TRP to perform communication with a base station;

[0022] Figure 5B is with Figure 5A A messaging diagram for a similar example scenario, but in this messaging diagram the UE receives UL and DL configuration parameters in separate radio resource configuration messages;

[0023] Figure 5C is with Figure 5A A message passing diagram for a similar example scenario, but in this message passing diagram, the base station sends the UL configuration parameters to the UE via the second TRP instead of the first TRP;

[0024] Figure 5D is with Figure 5A a message passing diagram for a similar example scenario, but in which the UE receives a response from the base station when performing the random access procedure via the first TRP instead of via the second TRP;

[0025] Figure 5E is with Figure 5A A message passing diagram for a similar example scenario, but in this message passing diagram, the UE receives the PDCCH order via the first TRP instead of the second TRP;

[0026] Fig. 6A is a flowchart of an example method in which: Figure 1A and / or Figure 1B the RAN node performing DL and UL communications with the UE through the first TRP and DL communications with the UE through the second TRP before subsequently sending the configuration parameter to the UE and performing DL and UL communications with the UE through the first TRP and the second TRP;

[0027] Figure 6B is with Fig. 6A a flow chart of a similar example method, but in the example method, when the UE supports multiple UL transmission timings for mTRP operation, the RAN node sends configuration parameters and performs DL and UL communications with the UE through the first TRP and the second TRP;

[0028] Fig. 7A is a flow chart of an example method in which, when a UE supports multiple transmission timings for mTRP operation, Figure 1A and / or Figure 1B The base station determines whether to include UL configuration parameters for UL communication through the second TRP;

[0029] Figure 7B is with Fig. 7A A flowchart of a similar example method, but in this example method, when the second TRP does not apply the same UL transmission timing as the first TRP, the base station performs Fig. 7A Determination in

[0030] Fig. 8A is a flowchart of an example method in which: Figure 1A and / or Figure 1B The RAN node determines whether to send a random access trigger command for the first TRP or the second TRP to the UE based on whether the RAN node triggers the UE to send a random access preamble to the first TRP or the second TRP;

[0031] Figure 8B is with Fig. 8A a flow chart of a similar example method, but in which the RAN node sends a first interface message to a first TRP and sends a second interface message to a second TRP;

[0032] Fig. 9 is a flowchart of an example method in which: Figure 1A and / or Figure 1B The base station determines whether to include an activation indication in a message to the UE based on whether the base station activates UL transmission of the UE through the second TRP;

[0033] Fig.10 is a flowchart of an example method in which: Figure 1A and / or Figure 1B the RAN node determining whether to perform a random access procedure to adjust UL transmission timing of UL communication via the second TRP based on whether the UE is synchronized with the RAN node through the second TRP;

[0034] Fig.11A is a flowchart of an example method in which: Figure 1A and / or Figure 1B The RAN node determines whether to send a random access response to the UE through the first TRP or the second TRP based on whether the RAN node receives the random access preamble through the first TRP or the second TRP;

[0035] Fig. 11B is with Fig.11A A flow chart of a similar example method, but in this example method, when the random access preamble is not a dedicated preamble, the RAN node performs Fig.11A determination;

[0036] Fig.12 is a flowchart of an example method in which: Figure 1BThe DU determines whether to include a DL configuration parameter or both a DL configuration parameter and a UL configuration parameter for communication through a second TRP in the DU to CU message based on whether the UE supports multiple UL transmission timings for mTRP operation;

[0037] Fig.13 is a flowchart of an example method in which: Figure 1A and / or Figure 1B The RAN node determines whether to enable mTRP communication of DL and UL based on whether the UE supports multiple UL transmission timings of mTRP operation;

[0038] Fig.14 is a flowchart of an example method in which: Figure 1A and / or Figure 1B The RAN node sends a first TA value and a second TA value to the UE, and uses a first set and a second set of HARQ process IDs to schedule UL transmissions through a first TRP and a second TRP.

[0039] Fig.15 is a flowchart of an example method in which: Figure 1A and / or Figure 1B The UE performs DL and UL communications with the base station through the first TRP and performs DL communication with the base station through the second TRP before receiving the trigger command from the base station;

[0040] Fig.16A is a flowchart of an example method in which: Figure 1A and / or Figure 1B The UE determines whether to perform a random access procedure with the base station for UL synchronization with the RAN node through the second TRP based on whether the message includes a random access configuration parameter for random access with the second TRP;

[0041] Fig. 16B is with Fig.16A A flow chart of a similar example method, but in the example method, the determination is based on whether the message indicates that UL synchronization of communications with a second TRP is required;

[0042] Fig.17A is a flowchart of an example method in which: Figure 1A and / or Figure 1B The UE determines whether to perform a random access procedure with the base station to perform UL synchronization with the RAN node through the second TRP based on whether the random access trigger command is received via the first TRP or the second TRP;

[0043] Fig. 17B is with Fig.17AA flow chart of a similar example method, but in the example method, the determination is based on whether the random access trigger command indicates a first TRP or a second TRP;

[0044] Fig.18 is a flowchart of an example method in which: Figure 1A and / or Figure 1B The UE determines whether to perform a random access procedure to perform UL synchronization with the RAN node through the second TRP based on whether the UL configuration parameter includes an access activation indication for the second TRP or whether the UE receives a random access trigger command to send a random access preamble to the second TRP; and

[0045] Fig.19 is a flowchart of an example method in which: Figure 1A and / or Figure 1B The UE maintains a first UL synchronization and a second UL synchronization and uses a first set and a second set of HARQ processes to send UL transmissions through a first TRP and a second TRP. DETAILED DESCRIPTION

[0046] First reference Figure 1A , the example wireless communication system 100 includes a UE 102, a base station (BS) 104, a base station 106, and a core network (CN) 110. The base stations 104 and 106 may operate in a RAN 105 connected to the core network (CN) 110. For example, the CN 110 may be implemented as an evolved packet core (EPC) 111 or a fifth generation (5G) core (5GC) 160. In another example, the CN 110 may also be implemented as a sixth generation (6G) core.

[0047] Base station 104 may cover one or more cells (e.g., cells 124 and 125) with one or more transmission and / or reception points (TRPs), and base station 106 may similarly cover one or more cells (e.g., cell 126) with one or more TRPs. For example, base station 104 operates cell 124 with TRPs 107-1 and 107-2, and operates cell 125 with TRP 107-3, and base station 106 operates cell 126 with TRPs 108-1 and 108-2. Cells 124 and 125 operate on the same one or more carrier frequencies. Cell 126 may operate on the same one or more carrier frequencies as cells 124 and 125. Alternatively, cell 126 may operate on one or more carrier frequencies different from cells 124 and 125. In some implementations, base station 104 connects each of TRPs 107-1, 107-2, and 107-3 via a fiber optic connection or an Ethernet connection. If base station 104 is a gNB, cells 124 and 125 are NR cells. If base station 104 is an (ng-)eNB, cells 124 and 125 are Evolved Universal Terrestrial Radio Access (EUTRA) cells. Similarly, if base station 106 is a gNB, cell 126 is an NR cell, and if base station 106 is an (ng-)eNB, cell 126 is an EUTRA cell. Cells 124, 125, and 126 may be located in the same radio access network notification area (RNA) or in different RNAs. In general, RAN 105 may include any number of base stations, and each of the base stations may cover one, two, three, or any other suitable number of cells. UE 102 may support at least 5G NR (or "NR" for short) or E-UTRA air interface to communicate with base station 104 via TRP 107-1, TRP 107-2, and / or TRP-3. Similarly, UE 102 may support at least 5G NR (or simply "NR") or E-UTRA air interface to communicate with base station 106 via TRP 108-1 and / or TRP 108-2. Each of base stations 104, 106 may be connected to CN 110 via an interface (e.g., S1 or NG interface). Base stations 104 and 106 may also be interconnected via an interface for interconnecting NG RAN nodes (e.g., X2 or Xn interface).

[0048] When a base station (e.g., base station 104 or 106) sends DL data via a TRP (e.g., TRP 107-1, TRP 107-2, TRP 107-3, TRP 108-1, or TRP 108-2), the base station 104 may generate a packet including the data and send the packet to the TRP 107-1. For example, the packet may be a fronthaul transport protocol data unit. The TRP extracts the data from the packet and sends the data. In some implementations, the base station 104 may include control information of time-critical control and management information directly related to the data in the packet, and the TRP may send the data based on the control information. In some implementations, 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., UE 102), the TRP generates a packet including the data and sends the packet to the base station 104. In some implementations, the data includes IQ data, a physical layer bit sequence, or a MAC PDU.

[0049] Among other components, the EPC 111 may also include a serving gateway (SGW) 112, a mobility management entity (MME) 114, and a packet data network gateway (PGW) 116. In general, the SGW 112 is configured to deliver user plane packets related to audio calls, video calls, Internet services, etc., and the MME 114 is configured to manage authentication, registration, paging, and other related functions. The PGW 116 provides connectivity from the UE 102 to one or more external packet data networks, such as an Internet network and / or an Internet Protocol (IP) Multimedia Subsystem (IMS) network. The 5GC 160 includes a user plane function (UPF) 162 and an access and mobility management function (AMF) 164 and / or a session management function (SMF) 166. Typically, UPF 162 is configured to deliver user plane packets associated with audio calls, video calls, Internet services, etc., AMF 164 is configured to manage authentication, registration, paging and other related functions, and SMF 166 is configured to manage PDU sessions.

[0050] like Figure 1A As shown, base station 104 supports cells 124 and 125, and base station 106 supports cell 126. Cells 124, 125, and 126 may partially overlap, so that UE 102 may select a cell, reselect a cell, or switch from one of cells 124, 125, and 126 to another. In order to exchange messages or information directly, base station 104 and base station 106 may support an X2 or Xn interface. In general, CN 110 may be connected to any suitable number of base stations supporting NR cells and / or EUTRA cells.

[0051] The base station 104 is equipped with processing hardware 130, which may include one or more general-purpose processors (e.g., CPUs) and non-transitory computer-readable memory storing instructions executed by the one or more general-purpose processors. In addition or alternatively, the processing hardware 130 may include a dedicated processing unit. The processing hardware 130 may include a PHY controller 132, which is configured to send data and control signals on a physical DL channel and send DL reference signals with 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 and / or receive UL reference signals on a physical UL channel with one or more user devices via one or more TRPs (e.g., TRP 107-1, TRP 107-2, and / or TRP 107-3). In an example implementation, the processing hardware 130 includes a MAC controller 134 configured to perform a random access (RA) procedure 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 send DL MAC PDUs to one or more user devices. The processing hardware 130 may also include an RRC controller 136 to implement procedures and message delivery at the RRC sublayer of the protocol communication stack. The base station 106 may include processing hardware 140 similar to the processing hardware 130. In particular, components 142, 144, and 146 may be similar to components 132, 134, and 136, respectively.

[0052] UE 102 is equipped with processing hardware 150, which may include one or more general-purpose processors such as a CPU, and non-transitory computer-readable memory storing machine-readable instructions that can be executed on one or more general-purpose processors, and / or a dedicated processing unit. PHY controller 152 is also configured to receive data and control signals on a physical DL channel and / or receive DL reference signals with 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). PHY controller 152 is also configured to send data and control signals on a physical UL channel and / or send UL reference signals with 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). In an example implementation, the processing hardware 150 includes a MAC controller 154 configured to perform random access procedures with the base station 104 or 106, manage UL timing advance for one or more user devices, send 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 may also include an RRC controller 156 to implement procedures and messaging at the RRC sublayer of the protocol communication stack.

[0053] Figure 1B An example distributed or decomposed implementation of one or both of the base stations 104, 106 is depicted. In this implementation, each of the base stations 104 and / or 106 includes a central unit (CU) 172 and one or more distributed units (DU) 174. The CU 172 includes processing hardware, such as one or more general-purpose processors (e.g., CPUs) and computer-readable memory storing machine-readable instructions executable on the general-purpose processors, and / or dedicated processing units. For example, the CU 172 may 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, the CU 172 may include an RLC controller configured to manage or control one or more RLC operations or processes. In other implementations, the CU 172 does not include an RLC controller.

[0054] Each of the DUs 174 also includes processing hardware, which may include one or more general-purpose processors (e.g., CPUs) and computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors, and / or a dedicated processing unit. For example, the processing hardware may include a MAC controller (e.g., MAC controllers 132, 142) configured to manage or control one or more MAC operations or processes (e.g., random access processes); and / or an RLC controller configured to manage or control one or more RLC operations or processes. The processing hardware may also include a physical layer controller configured to manage or control one or more physical layer operations or processes.

[0055] In some implementations, the RAN 105 supports integrated access and backhaul (IAB) functionality. In some implementations, the DU 174 operates as an (IAB) node and the CU 172 operates as an IAB donor.

[0056] In some implementations, the CU 172 may include a logical node CU-CP 172A that hosts a control plane portion of a PDCP protocol of the CU 172. The CU 172 may also include a logical node CU-UP 172B that hosts a user plane portion of a PDCP protocol and / or SDAP protocol of the CU 172. The CU-CP 172A may send control information (e.g., RRC messages, F1 application protocol messages), and the CU-UP 172B may send data packets (e.g., SDAP PDUs or IP packets).

[0057] The CU-CP 172A may be connected to multiple CU-UPs 172B via an E1 interface. The CU-CP 172A selects an appropriate CU-UP 172B for the requested service of the UE 102. In some implementations, a single CU-UP 172B may be connected to multiple CU-CPs 172A via an E1 interface. If the CU-CP 172A and the DU 174 belong to a gNB, the CU-CP 172A may be connected to one or more DUs 174 via an F1-C interface and / or an F1-U interface. If the CU-CP 172A and the DU 174 belong to an ng-eNB, the CU-CP 172A may be connected to the DU 174 via a W1-C interface and / or a W1-U interface. In some implementations, one DU 174 may be connected to multiple CU-UPs 172B under the control of the same CU-CP 172A. In such implementations, the connection between the CU-UP 172B and the DU 174 is established by the CU-CP 172A using a bearer context management function.

[0058] Figure 2A An example protocol stack 200 is shown in a simplified manner according to which a UE 102 may communicate with an eNB / ng-eNB or a gNB (e.g., one or both of base stations 104, 106).

[0059] In the example stack 200, the physical layer (PHY) 202A of EUTRA provides transport channels to the EUTRA MAC sublayer 204A, which in turn provides logical channels to the EUTRA RLC sublayer 206A. The EUTRA RLC sublayer 206A in turn provides RLC channels to the EUTRA PDCP sublayer 208 and, in some cases, to the NR PDCP sublayer 210. Similarly, the NRRPHY 202B provides transport channels to the NR MAC sublayer 204B, which in turn provides logical channels to the NR RLC sublayer 206B. The NR RLC sublayer 206B in turn provides data transfer services to the NR PDCP sublayer 210. The NR PDCP sublayer 210 may in turn provide data to the SDAP sublayer 212 or the RRC sublayer ( Figure 2A (not shown) provides data transfer services. In some implementations, such as Figure 2A As shown, UE 102 supports both EUTRA and NR stacks to support switching between EUTRA and NR base stations and / or support dual connectivity (DC) through EUTRA and NR interfaces. Figure 2A As shown, the UE 102 may support NR PDCP 210 layered on top of the EUTRA RLC 206A, and SDAP sublayer 212 layered on top of the NR PDCP sublayer 210.

[0060] The EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 receive packets, which may be referred to as SDUs (e.g., from an IP layer layered directly or indirectly above the PDCP layer 208 or 210), and output packets, which may be referred to as PDUs (e.g., to the RLC layer 206A or 206B). Unless the difference between SDUs and PDUs is relevant, for simplicity, this disclosure refers to both SDUs and PDUs as "packets."

[0061] On the control plane, for example, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 may provide the RRC sublayer with Figure 2AThe NR PDCP sublayer 210 may provide a signaling radio bearer (SRB) to exchange RRC messages or NAS messages. On the user plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 may provide a data radio bearer (DRB) to support data exchange. The data exchanged on the NR PDCP sublayer 210 may be an SDAP PDU, an IP packet, or an Ethernet packet.

[0062] Therefore, the radio protocol stack can be functionally split, e.g. Figure 2B 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 SRBs to the RRC 214, and the NR PDCP 210 provides DRBs to the SDAP 212 and provides SRBs to the RRC 214.

[0063] Figure 3A Detailed structure 300A of the NR layer 2 protocol stack 200 or 250 of the base station 104 or 106 is shown. PHY 202 ( Figure 3A The MAC sublayer 204 includes a scheduling and / or priority handling function 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 with a specific user device. The MAC sublayer 204 also includes a hybrid automatic repeat request (HARQ) entity, each entity for DL ​​transmission and / or UL transmission with a specific user device on a specific DL component carrier (CC) and / or a specific UL CC. The RLC sublayer 206 includes segmentation and automatic repeat request (ARQ) functions for DL ​​data and UL data communicated with one or more UEs. The PDCP sublayer 210 provides a radio bearer to the SDAP sublayer 212, and includes (i) security and (ii) robust header compression (ROHC) functions for (i) integrity protection and / or encryption / description and (ii) header compression / decompression, respectively. The SDAP sublayer 212 provides 5GC QoS flows to the upper layer.

[0064] Figure 3B Detailed structure 300B of the NR layer 2 protocol stack 200 or 250 of the UE 102 is shown, similar to structure 300A. PHY 202 ( Figure 3BThe MAC sublayer 204 includes one or more HARQ entities, each HARQ entity being used for DL ​​transmission and / or UL transmission with the base station 104 or 106 on a specific DL CC and / or a specific UL CC. The MAC sublayer 204 also includes logical channel prioritization and multiplexing functions for UL transmission to the base station 104 or 106, and includes a demultiplexing function for DL ​​transmission from the base station 104 or 106. The RLC sublayer 206 includes segmentation and automatic repeat request (ARQ) functions for DL ​​data and UL data communicated with the base station 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 / description and (ii) header compression / decompression, respectively. The SDAP sublayer 212 provides 5GC QoS flow to the upper layer.

[0065] FIG. 4A to FIG. 4C Shows the specific CC y Different implementations of a HARQ entity for multi-TRP (mTRP) operation on (e.g., UL CC or DL ​​CC), which HARQ entity can be implemented in UE 102, base station 104 or 106, or DU 174 of base station 104 or 106.

[0066] First, reference is made to the HARQ entity 400A. Figure 4A In some implementations, the HARQ entity 400A includes HARQ processes 1, ..., N for communicating with TPRs 1, ..., m. N is an integer greater than zero, and m is an integer greater than zero. For example, N is 8, 16, 32, etc., and m is 2, 3, 4, etc.

[0067] Next, Figure 4B A further implementation of a HARQ entity 400B is depicted, similar to the HARQ entity 400A. The difference between the implementations of the HARQ entity 400B and 400A is that the HARQ entity 400B divides the HARQ processes 1, ..., N into m groups, where each group is used for communication with a specific TRP.

[0068] Next, Figure 4C The implementation of a HARQ entity 400C (eg, HARQ entity k) is depicted, which is similar to the HARQ entity 400A. The difference between the implementations of the HARQ entity 400C and 400A is that the HARQ entity 400C is used to perform a specific CC (eg, CC k ) with a specific TRP (e.g., TRP k), where 1<=k<=m. In other words, UE 102 uses HARQ entities 1, ..., m to communicate with a RAN node (e.g., base station 104 or 106 or DU 174) via TRP 1, ..., m on each UL CC, respectively. Similarly, the RAN node uses HARQ entities 1, ..., m to communicate with UE 102 via TRP 1, ..., m of the RAN node (e.g., base station 104 or 106 or DU 174) on each DL CC, respectively.

[0069] Next, refer to FIG. 5A to FIG. 5E To discuss the Figure 1A The various components of mTRP are described and several example scenarios of mTRP operation are covered. FIG. 5A to FIG. 5E Identical events are marked with the same reference numerals.

[0070] First reference Figure 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) via TRP 107-1 (e.g., periodically) and broadcasts 508, 510 system information. In some implementations, the system information includes a master information block (MIB) and / or a system information block (SIB). In some examples, the SIB includes SIB1, and also includes SIB2, SIB3, SIB4, and / or SIB5. UE 102 initially operates 502 in an idle state (e.g., RRC_IDLE state). UE 102 in the idle state receives 504, 506 SSBs from base station 104 via TRP 107-1 and receives 508, 510 system information. In some implementations, the UE 102 detects that the base station 104 transmits the SSB via the TRP 107-1. In some implementations, the UE 102 then performs downlink synchronization with the base station 104 on the cell 124 via the TRP 107-1 using one of the SSBs and receives 508, 510 system information via the TRP 107-1 based on the SSBs.

[0071] Later, the UE 102 determines to perform 590 a random access procedure to perform 592 an RRC connection establishment procedure. In response to the determination, the UE 102 sends 512 a first random access preamble to the TRP 107-1 on a time / frequency resource and / or a random access channel (RACH) opportunity. The TRP 107-1 then forwards 514 the first random access preamble to the base station 104. In some implementations, the UE 102 selects an SSB from the SSBs for the random access procedure for which the RSRP obtained by the UE 102 is above a first threshold (e.g., rsrp-ThresholdSSB). In other implementations, in the event that the RSRP of any SSB in the SSBs is not above the first threshold, the UE 102 selects an SSB from the SSBs and uses the SSB to determine the first random access preamble. In some such cases, the UE 102 selects the SSB randomly from the SSBs or selects based on the UE implementation. Then, the UE 102 determines a first random access preamble, a time / frequency resource, and / or a RACH opportunity based on the selected SSB and a random access configuration parameter included in the system information (e.g., SIB1). In some implementations, the random access configuration parameter indicates one or more associations between (i) the SSB and (ii) the random access preamble, the RACH opportunity, and / or the time / frequency resource. Based on the selected SSB and the association, the UE 102 determines a first random access preamble, a RACH opportunity, and / or a time / frequency resource to send the first random access preamble.

[0072] In response to the first random access preamble, the base station 104 sends 516 a first random access response to the TRP 107-1. The TRP 107-1 then forwards 518 the first random access response to the UE 102. In some implementations, the base station 104 or the TRP 107-1 identifies an SSB associated with the first random access preamble, RACH opportunity, and / or time / frequency resource. In some cases where a single SSB is associated with the first random access preamble, RACH opportunity, and / or time / frequency resource, the identified SSB is the SSB selected by the UE 102. In some cases where multiple SSBs are associated with the first random access preamble, RACH opportunity, and / or time / frequency resource, the identified SSB is the same as or different from the SSB selected by the UE 102. In such implementations, the base station 104 sends the first random access response to the UE 102 via the TRP 107-1 based on the identified SSB. The base station 104 includes a first preamble ID and a first TA command in a 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 determines or maintains 520 an uplink synchronized (e.g., time aligned) with the TRP 107-1 after applying the first TA value (e.g., in response to applying the first TA value). The UE 102 applies the first TA value to send UL transmissions (e.g., PUCCH transmissions, PUSCH transmissions, and / or sounding reference signal transmissions) until a new or different TA value that updates the first TA value is received from the base station 104. In some implementations, the UE 102 starts a first time alignment timer (TAT) after or upon receiving the first TA command to maintain a UL synchronization state with the TRP 107-1 or the base station 104. In some implementations, the base station 104 includes a UL grant (i.e., a RAR grant) in the random access response.

[0073] In some implementations, the base station 104 starts a first TAT to maintain first UL synchronization of UL and / or DL ​​communications with the UE 102 via the TRP 107-1 after sending a random access response or a first TA command to the UE 102. In some implementations, the TRP 107-1 generates timing information for or based on a first random access preamble received from the UE 102 and sends the timing information to the base station 104. In some examples, the timing information indicates a propagation delay or a propagation delay offset. Based on the timing information received from the TRP 107-1, the base station 104 determines a first TA value.

[0074] Figure 5A 5. Blocks 512, 514, 516, 518, and 520 are collectively referred to as a random access procedure 590.

[0075] During or after the random access procedure 590, the UE 102 sends 522, 524 an RRC setup request message (e.g., an RRCSetupRequest message) to the base station via TRP 107-1. In some implementations, the UE 102 sends the RRC setup request message using the UL grant received in the random access response. In response to the RRC setup request message, the base station 104 sends 526, 528 an RRC setup message (e.g., an RRCSetup message) to the UE 102 via TRP 107-1. In some implementations, the base station 104 sends a MAC PDU including contention resolution (e.g., a MAC control element (CE)) to the UE 102 to resolve contention for the random access procedure. In some implementations, the base station 104 includes the RRC setup message in the MAC PDU. In further implementations, after sending the MAC PDU, the base station 104 sends another MAC PDU including the RRC setup message to the UE 102. In response to the RRC setup message, the UE 102 transitions 530 to a connected state (e.g., RRC_CONNECTED) and sends 532, 534 an RRC setup complete message (e.g., RRCSetupComplete message) to the base station 104 via the TRP 107-1. In some implementations, after performing the RRC connection establishment procedure with the UE 102, the base station 104 performs a security activation procedure with the UE 102 to activate security protection (e.g., integrity protection / integrity check and encryption / decryption) for UL data and DL data transmitted between the UE 102 and the base station 104. In further implementations, 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 SRB2 and / or DRB for the UE 102.

[0076] After performing an RRC connection establishment procedure, a security activation procedure, or a radio bearer configuration procedure, the base station 104 sends 536, 538 an RRC reconfiguration message (e.g., an RRCReconfiguration message) including a channel state information (CSI) resource configuration and a CSI report configuration to the UE 102 via TRP 107-1. In response, the UE 102 sends 540, 542 an RRC reconfiguration completion message (e.g., an RRCReconfigurationComplete message) to the base station 104 via TRP 107-1. In some implementations, the CSI resource configuration includes configuring configuration parameters of a channel state information reference signal (CSI-RS) for measurement by the UE 102. The base station 104 sends the CSI-RS via TRP 107-2 according to the CSI resource configuration. The UE 102 performs measurements on the CSI-RS according to the CSI resource configuration. In some implementations, the CSI resource configuration includes configuring configuration parameters of an SSB for measurement by the UE 102. The base station 104 sends the SSB via TRP 107-2. The UE 102 performs measurements on the SSB according to the CSI resource configuration. In other implementations, 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 sends the SSB via TRP 107-2, 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 of the CSI-RS or SSB and sends the CSI report 544, 546 to the base station 104 via TRP 107-1. In some implementations, the UE 102 sends the CSI report to the base station 104 on the PUCCH via TRP 107-1. In some implementations, the CSI report configuration configures periodic or semi-persistent reporting, or the CSI report configuration configures semi-persistent or aperiodic reporting triggered by DCI. The CSI report includes a periodic CSI report, a semi-persistent CSI report and / or an aperiodic CSI report.

[0077] In some implementations, the base station 104 includes the CSI resource configuration and / or the CSI report configuration in a CSI measurement configuration (e.g., CSI-MeasConfig IE). The base station 104 then includes the CSI measurement configuration in the RRC reconfiguration message of events 536, 538. In other implementations, the CSI resource configuration includes NZP-CSI-RS-Resource IE, NZP-CSI-RS-ResourceSet IE, CSI-SSB-ResourceSet IE, CSI-ResourceConfig IE, and / or CSI-ReportConfig IE.

[0078] Figure 5A Boxes 536 , 538 , 540 , 542 , 544 , and 546 are collectively referred to as a CSI resource configuration and CSI reporting process 594 .

[0079] After receiving the CSI report at event 546, the base station 104 determines, based on the CSI report, to communicate with the UE 102 via TRP 107-2 while maintaining a link with the UE 102 via TRP 107-1. In some implementations, the base station 104 makes the determination based on one or more capabilities of the UE 102. In response to the determination, the base station 104 sends 548, 550 an RRC reconfiguration message to the UE 102 via TRP 107-1, the RRC reconfiguration message including DL and UL configuration parameters for DL ​​and UL communications, respectively, with the base station 104 via TRP 107-2. In some implementations, the base station 104 includes the DL and UL configuration parameters in a CellGroupConfig IE and includes the CellGroupConfig IE in the RRC reconfiguration message. In some implementations, the base station 104 includes the DL configuration parameters in a bandwidth part (BW) IE such as a BWP-DownlinkDedicated IE and includes the BWP-DownlinkDedicated IE in the RRC reconfiguration message. In some implementations, the base station 104 includes the UL configuration parameters in a BWP-UplinkDedicated IE and includes the BWP-UplinkDedicated IE in the RRC reconfiguration message.

[0080] In response to the RRC reconfiguration complete message, UE 102 sends 552, 554 an RRC reconfiguration complete message to base station 104 via TRP 107-1. In some implementations, UE 102 applies the DL configuration parameters upon receiving the RRC reconfiguration message at event 554. In such implementations, UE 102 performs 556 DL communications with base station 104 via TRP 107-2 in accordance with the DL configuration parameters while performing DL and UL communications with base station 104 via TRP 107-1. In some implementations, UE 102 refrains from performing UL communications in accordance with the UL configuration parameters until after performing a random access procedure with base station 104 via TRP 107-2 at event 598. In further implementations, UE 102 refrains from performing DL communications with base station 104 via TRP 107-2 until after performing a random access procedure with base station 104 via TRP 107-2 at event 598. In some implementations, base station 104 avoids performing UL communications and / or configuring UL configuration parameters until after a random access procedure with base station 104 via TRP 107-2 is completed at event 598. In some implementations, base station 104 avoids performing DL communications and / or configuring DL configuration parameters until after a random access procedure with base station 104 via TRP 107-2 is completed at event 598.

[0081] In some implementations, base station 104 and UE 102 use Figure 4A , Figure 4B or Figure 4C 107-2 to perform DL communication with base station 104 via TRP 107-1 and TRP 107-2 at event 556. In some cases, such as with Figure 4B The DL configuration parameters of events 548 and 550 of the HARQ entity 400B include HARQ configuration parameters. The HARQ configuration parameters configure 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 used 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 implementations, the first set of HARQ process IDs and the second set of HARQ process IDs are not the same. In other implementations, some of the first set of HARQ process IDs and the second set of HARQ process IDs are the same and others are different.

[0082] In some implementations, the base station 104 sends one or more MAC control elements (CEs) or DCIs to the UE 102 to change or update one or more HARQ process IDs in the first set of HARQ process IDs. In some implementations, the base station 104 sends one or more MAC CEs or DCIs to the UE 102 to change or update one or more HARQ process IDs in the second set of HARQ process IDs. In some alternative implementations, the base station 104 does not configure the first set of HARQ process IDs and the second set of HARQ process IDs in the DL configuration parameters. In some implementations, the base station 104 determines the first set of HARQ process IDs and the second set of HARQ process IDs for mTRP operation based on preconfiguration. In a further implementation, the first set of HARQ process IDs and the second set of HARQ process IDs are specific, predetermined IDs (e.g., as specified in the 3GPP specification). In a further implementation, the base station 104 determines the first set of HARQ process IDs and the second set of HARQ process IDs based on rules.

[0083] In some implementations, when the base station 104 determines to schedule the UE 102 to receive a DL transmission for the TRP 107-1, the base station 104 selects a HARQ process ID from the first set of HARQ process IDs and sends a DCI including a DL assignment and the selected HARQ process ID to the UE 102. 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 send an UL transmission to the TRP 107-2, the base station 104 selects a HARQ process ID from the second set of HARQ process IDs and sends a DCI including a UL grant and the selected HARQ process ID to the UE 102. The UE 102 uses the HARQ process identified by the selected HARQ process ID and uses the HARQ process and the DL assignment to receive the DL transmission from the base station 104.

[0084] In some implementations, the one or more capabilities include at least one first capability indicating that the UE 102 supports mTRP operation (e.g., a Release 16 capability field / IE and / or a Release 17 capability field / IE for mTRP operation in 3GPP specification 38.306 or 38.331 v17.1.0 or higher). In some implementations, the base station 104 determines, based on the at least one first capability, DL configuration parameters configured for DL ​​communication with the base station 104 via the TRP 107-2. In some implementations, the base station 104 determines, based on the at least one first capability, UL configuration parameters for UL communication with the base station 104 via the TRP 107-2. In the case where the base station 104 includes the DU 174 and the CU 172, the DU 174 makes the determination.

[0085] In some implementations, the one or more capabilities include at least one second capability. In some such implementations, the at least one second capability indicates that the UE 102 supports multiple UL transmission timings (i.e., operation of two or more TAs) for mTRP operation with a serving cell. In further implementations, the at least one second capability indicates that the UE 102 supports multiple UL transmission timings (of mTRP operation) with a serving cell and a non-serving cell. The physical cell index (PCI) of the non-serving cell is different from the PCI of the serving cell. In some implementations, the at least one second capability includes the number of UL transmission timings (of mTRP operation) supported by the UE 102 with the serving cell and / or across all serving cells configured / activated for the UE 102. In further implementations, the at least one second capability does not include the number of UL transmission timings (of mTRP operation) and indicates that the UE 102 supports a default number (e.g., 2) of UL transmission timings. In some implementations, the base station 104 determines the UL configuration parameters configured for UL communication with the base station 104 via TRP 107-2 based on the at least one second capability. Where the base station 104 includes a DU 174 and a CU 172, the DU 174 makes the determination.

[0086] In some implementations, the base station 104 receives one or more capabilities from the UE 102 after receiving an RRC setup complete message or performing a security activation procedure with the UE 102. In some implementations, the base station 104 sends a UE capability query message (e.g., a UECapabilityEnquiry message) to the UE 102 and receives a UE capability information message (e.g., a UECapabilityInformation message) including one or more capabilities from the UE in response.

[0087] In other implementations, base station 104 receives a CN to BS message including one or more capabilities from CN 110 (e.g., after receiving the RRC setup complete message). In some implementations, base station 104 sends a BS to CN message to CN 110 after receiving the RRC setup complete message, and CN 110 sends a CN to BS message after receiving the BS to CN message (e.g., in response to receiving the BS to CN message). In some implementations, UE 102 sends a NAS message (e.g., a Registration Request message or a Registration Complete message) including a capability ID identifying one or more capabilities to CN 110, and CN 110 obtains the one or more capabilities from the capability ID. In other implementations, UE 102 performs a registration procedure with CN 110 via a base station (e.g., base station 104 or 106) to register with CN 110 before event 502. During the registration process, UE 102 receives a UE capability query message (e.g., a UECapabilityEnquiry message) from the base station and sends a UE capability information message (e.g., a UECapabilityInformation message) including one or more capabilities to the base station. The base station sends a BS to CN message including one or more capabilities to CN 110, and CN 110 stores the one or more capabilities. In some implementations, the CN to BS message and the BS to CN message are NG Application Protocol (NGAP) messages. In the case where the base station 104 includes a DU 174 and a CU 172, the CU 172 sends a CU to DU message including one or more capabilities to the DU 174. In some implementations, the CU to DU message is an F1 Application Protocol (F1AP) message.

[0088] In some implementations, the base station 104 may include the random access configuration parameters in the RRC reconfiguration message for the UE 102 to perform 598 the random access procedure. In some implementations, the random access configuration parameters are dedicated to the UE 102. For example, the base station 104 generates a RACH configuration (e.g., a RACH-ConfigDedicated, RACH-ConfigDedicated-r18, or RACH-ConfigDedicated-v1800 IE) that includes the random access configuration parameters dedicated to the UE 102. In some implementations, the format of the RRCReconfiguration message includes a ReconfigurationWithSync IE, and the ReconfigurationWithSync IE includes a RACH-ConfigDedicated IE (e.g., a RACH configuration or includes a random access configuration parameter) (e.g., as specified in 3GPP specification 38.331 v17.0.0 or later). In the case where the RRC reconfiguration message is an RRCReconfiguration message, the base station 104 includes the RACH configuration or random access configuration parameters of the RRCReconfiguration message in the RRCReconfiguration message, instead of including the ReconfigurationWithSync IE and wrapping the RACH configuration or random access configuration parameters in the ReconfigurationWithSync IE. If the base station 104 uses the ReconfigurationWithSync IE to include the random access configuration parameters, the ReconfigurationWithSync IE causes the UE 102 to perform a handover, which results in a communication interruption between the UE 102 and the base station 104. In other implementations, the base station 104 avoids including the random access configuration parameters in the RRC reconfiguration message.

[0089] In some implementations, 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 obtain the (second) UL synchronization for communication between the UE 102 and the TRP 107-1, while maintaining the 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 a further implementation, the base station 104 includes a configuration (e.g., a field or IE (e.g., an RRC Release 18 field or IE)) in the RRC reconfiguration message, thereby indicating that UL synchronization is required for communication between the UE 102 and the TRP 107-2. In other words, the configuration enables operation of two TAs for communication between UE 102 and base station 104 (e.g., between UE 102 and TRP 107-1 and between UE 102 and TRP 107-2, respectively).

[0090] In some implementations, the UE 102 initiates a random access procedure 598 in response to receiving the field or IE before sending an 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 TRP 107-2. In some such implementations, if the RRC reconfiguration message does not include the field or IE, the UE 102 does not initiate a random access procedure and sends an UL transmission to the base station via TRP 107-2. In further implementations, the UE 102 avoids sending an UL transmission to the base station via TRP 107-2 in response to receiving the field or IE. In some such cases, the UE 102 does not send a random access preamble to the base station 104 via TRP 107-2 until a PDCCH instruction is received from the base station (e.g., events 558, 560, 559, 561).

[0091] Figure 5A Boxes 548, 550, 552, 554, and 556 are collectively referred to as the TRP configuration process 596A.

[0092] In some implementations, after receiving the RRC reconfiguration message at event 538, after performing the CSI resource configuration and CSI reporting process 594, or after performing the TRP configuration process 596A with the base station 104, the UE 102 receives 562, 564 RS from the base station 104 via TRP 107-2. Depending on the implementation, the RS is configured in the CSI resource configuration at event 538, and the events 562, 564 occur after receiving the RRC reconfiguration message at event 538, during or after the CSI resource configuration and CSI reporting process 594, or during or after the TRP configuration process 596A. After performing the TRP configuration process 596A with the base station 104, the UE 102 initiates 598 a random access procedure. In response to initiating the random access procedure, the UE 102 sends 566, 568 a second random access preamble to the base station 104 via TRP 107-2 on the time / frequency resource and the random access channel (RACH) opportunity. In response to the second random access preamble, the base station 104 sends 570, 572 a second random access response to the UE 102 via the TRP 107-2. The base station 104 includes the second preamble ID and the 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 determines or maintains 574 an uplink synchronized with the TRP 107-2 after applying the second TA value (e.g., in response to applying the second TA value). The UE 102 applies the second TA value to send UL transmissions (e.g., PUCCH transmissions, PUSCH transmissions, and / or SRS transmissions) until the UE 102 receives a new or different TA value that updates the second TA value from the base station 104. In some implementations, the UE 102 starts a second TAT after or upon receiving the second TA command to maintain or manage a UL synchronization state with the TRP 107-2 or the base station 104. In some implementations, the base station 104 includes a UL grant (e.g., a RAR grant) in the second random access response, and the UE 102 sends a UL MAC PDU to the base station 104 via 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 the identification, the base station 104 generates a DCI and a CRC for the DCI, scrambles the CRC with the C-RNTI, and sends the DCI and the scrambled CRC to the UE 102 on the PDCCH. In some implementations, the DCI includes n UL grants.After receiving the DCI and the scrambled CRC on the PDCCH, the UE 102 determines that the content-based random access procedure 598 is successfully performed. 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 is successfully performed in response to receiving the second random access response message.

[0093] In some implementations, the base station 104 starts a second TAT to maintain second UL synchronization of UL and / or DL ​​communications with the UE 102 via the TRP 107-2 after sending the second TA command to the UE 102 (e.g., in response to sending the second TA command to the UE 102). In some implementations, the TRP 107-1 generates timing information for the second random access preamble received from the UE 102 and sends the timing information to the base station 104. For example, the timing information indicates a propagation delay or a propagation delay offset. Based on the timing information received from the TRP 107-2, the base station 104 determines a second TA value.

[0094] Figure 5A Boxes 566 , 568 , 570 , 572 , and 574 are collectively referred to as a random access procedure 598 .

[0095] In some implementations, the UE 102 suspends communication (e.g., reception of DL channels / RSs or transmission of UL channels / RSs) with the base station 104 via the TRP 107-1 while performing the random access procedure 598. Depending on the implementation, the UE 102 does so if it cannot simultaneously perform the random access procedure based on a UL beam or RS (i.e., toward a TRP) and transmit UL and DL transmissions (i.e., unrelated to the random access procedure) based on another UL beam or RS (i.e., toward another TRP). In other implementations, the UE 102 continues communication with the base station 104 via the TRP 107-2 while performing the random access procedure 598. After successfully completing 598 the random access procedure, the UE performs 576 DL and UL communication with the BS via the TRP 107-1 and the TRP 107-2 according to the first TA value and the second TA value, respectively.

[0096] In some implementations, the base station 104 and the UE 102 use (eg Figure 4A , Figure 4B or Figure 4C ) HARQ entity to perform UL communication with base station 104 via TRP 107-1 and TRP 107-2 at event 576. Figure 4BIn some cases, the UL configuration parameters of events 548, 550 include HARQ configuration parameters. The HARQ configuration parameters configure 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 used 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 implementations, the first set of HARQ process IDs and the second set of HARQ process IDs are not the same. In other implementations, some of the first set of HARQ process IDs and the second set of HARQ process IDs are the same and others are different.

[0097] In some implementations, the base station 104 sends one or more MAC CEs or DCIs to the UE 102 to change or update one or more HARQ process IDs in the first set of HARQ process IDs. In some further implementations, the base station 104 sends one or more MAC CEs or DCIs to the UE 102 to change or update one or more HARQ process IDs in the second set of HARQ process IDs. In some alternative implementations, the base station 104 does not configure the first set of HARQ process IDs and the second set of HARQ process IDs in the UL configuration parameters. In some implementations, the base station 104 determines the first set of HARQ process IDs and the second set of HARQ process IDs for mTRP operation based on preconfiguration. In a further implementation, the first set of HARQ process IDs and the second set of HARQ process IDs are specified sets (e.g., as specified in the 3GPP specification). In a further implementation, the base station 104 determines the first set of HARQ process IDs and the second set of HARQ process IDs based on rules.

[0098] In some implementations, when the base station 104 determines to schedule the UE 102 to send an UL transmission to the TRP 107-1, the base station 104 selects a HARQ process ID from the first set of HARQ process IDs and sends a DCI including an UL grant and the selected HARQ process ID to the UE 102. The UE 102 uses the HARQ process identified by the selected HARQ process ID and uses the HARQ process and the UL grant to send an UL transmission to the base station 104. Similarly, when the base station 104 determines to schedule the UE 102 to send an UL transmission to the TRP 107-2, the base station 104 selects a HARQ process ID from the second set of HARQ process IDs and sends a DCI including an UL grant and the selected HARQ process ID to the UE 102. The UE 102 uses the HARQ process identified by the selected HARQ process ID and uses the HARQ process and the UL grant to send an UL transmission to the base station 104.

[0099] In some implementations, after receiving the RRC reconfiguration complete message at event 554, the base station 104 sends 558, 560 a PDCCH command to the UE 102 via TRP 107-2, so that the UE 102 initiates a random access procedure 598 with the base station 104 via TRP 107-2. In some implementations, the PDCCH command includes an RS index and a random access preamble index. Alternatively, the base station 104 sends the PDCCH command to the UE 102 via TRP 107-1. In response to the PDCCH command, the UE 102 sends the random access preamble to the base station 104 via TRP 107-2 at event 566. In some implementations, the random access preamble index includes a value of a second preamble ID that identifies the second random access preamble. Therefore, the UE 102 determines the second random access preamble according to the random access preamble index. In other implementations, the random access preamble index includes a value indicating or instructing the UE 102 to determine the random access preamble. Therefore, 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.

[0100] In some implementations, the PDCCH instruction is a DCI. The base station 104 generates a DCI and a CRC for the DCI, scrambles the CRC with a C-RNTI, and sends the DCI and the scrambled CRC (e.g., via an optical fiber connection) to the TRP 107-2. Then, the TRP 107-2 sends the DCI and the scrambled CRC to the UE 102 on the PDCCH. In some implementations, the base station 104 sends a first packet including the DCI and the scrambled CRC to the TRP 107-2. In some implementations, the base station 104 sends control information configuring or indicating the time and / or frequency resources of the PDCCH to the TRP 107-2. In some implementations, the time and / or frequency resources include subcarriers, resource elements, or physical resource blocks. The TRP 107-2 sends the DCI and the scrambled CRC on the time and / or frequency resources according to the control information. In some implementations, the base station 104 includes the control information in the first packet. In other implementations, base station 104 sends a second packet including control information to TRP 107-2 instead of the first packet. In other implementations, base station 104 does not send the control information of the DCI and the scrambled CRC to TRP 107-2. In such implementations, TRP 107-2 determines the time and / or frequency resources of the PDCCH and sends the DCI and the scrambled CRC on the time and / or frequency resources.

[0101] In some implementations, the RS index (e.g., SSB index) identifies one of the SSBs. In some such implementations, the base station 104 determines or decodes the SSB index indicated in the CSI report. In further implementations, the base station 104 determines or decodes the SSB index based on the radio resource (e.g., PUCCH resource) in which the base station 104 receives one of the CSI reports for the SSB. In some such implementations, the base station 104 configures different radio resources for the UE 102 to send the 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 that configures different radio resources (e.g., PUCCH resources) for the UE 102 to send the CSI report for each of the SSBs. In some implementations, the UE 102 determines the time / frequency resources and / or RACH timing based on the SSB (e.g., indicated in the RS index) and the random access configuration parameters received in the system information, and sends the second random access preamble on the time / frequency resources and / or RACH timing. In other implementations, the UE 102 determines the time / frequency resources and / or RACH timing based on the SSB (e.g., indicated in the RS index) and the random access configuration parameters received in the RRC reconfiguration message of event 550, and sends the second random access preamble on the time / frequency resources and / or RACH timing.

[0102] In other implementations, the RS index (e.g., CSI-RS index) identifies one of the CSI-RSs. In some implementations, the base station 104 determines or decodes the CSI-RS index indicated in the CSI report. In further implementations, the base station 104 determines or decodes the CSI-RS index based on the radio resource (e.g., PUCCH resource) in which the base station 104 receives the CSI report for the CSI-RS. In some such implementations, the base station 104 configures different radio resources for the UE 102 to send the CSI report for each of the CSI-RSs. In some examples, the base station 104 includes a configuration in the RRC reconfiguration message of event 536 that configures different radio resources (e.g., PUCCH resources) for the UE 102 to send the CSI report for each of the CSI-RSs. In some implementations, UE 102 determines the time / frequency resources and / or RACH opportunities based on the CSI-RS (e.g., indicated in the RS index) and the random access configuration parameters in the RRC reconfiguration message received by UE 102 at event 550. UE 102 sends the second random access preamble on the time / frequency resources and / or RACH opportunities. In some implementations, the random access configuration parameters indicate one or more associations between the CSI-RS and the RACH opportunities and / or the time / frequency resources.

[0103] In some implementations, UE 102 determines transmission characteristics (e.g., spatial transmission filters / parameters) based on or by reference to the RS index in the PDCCH command, and uses the determined transmission characteristics to send a second random access preamble to TRP 107-2. In some examples, UE 102 uses reception characteristics for receiving 564 the RS identified by the RS index to derive the transmission characteristics. In some implementations, the transmission characteristics include phase, power and / or transmission precoders. In some implementations, UE 102 further uses DL and / or UL configuration parameters of event 550 to determine the transmission characteristics. In further implementations, UE 102 uses configuration parameters in the system information of event 510 to determine the transmission characteristics. In some implementations, UE 102 does not determine transmission characteristics (e.g., spatial transmission filters / parameters) based on or by reference to the RS index in the PDCCH command, and uses the determined transmission characteristics to send a second random access preamble to TRP 107-2.

[0104] In some implementations, UE 102 initiates 598 a random access procedure in response to random access configuration parameters received at event 550 and after receiving the RS at event 564. In such implementations, base station 104 does not send a PDCCH command to cause UE 102 to perform random access procedure 598.

[0105] In some implementations, the RRC reconfiguration message of event 550 includes configuration parameters (e.g., for PDCCH configuration, search space configuration, and / or control resource set (CORESET) configuration) for UE 102 to receive DL transmissions from TRP 107-2. In some implementations, UE 102 receives a second random access response based on the configuration parameters. In other implementations, the system information of event 510 includes configuration parameters for UE 102 to receive a random access response from TRP 107-2. In such implementations, UE 102 receives a second random access response based on the configuration parameters. In some implementations, UE 102 receives a second random access response from TRP 107-2 using the reception characteristics for receiving 564 RS.

[0106] Although TRP 107-2 is used in scenario 500A, the above description can be applied to scenarios where TRP 107-3 is used instead of TRP 107-2. In such scenarios, after successfully completing a random access procedure with the base station via TRP 107-3 and cell 125 similar to process 598, the UE performs DL and UL communications with the base station via TRP 107-1 and TRP 107-3 according to the first TA value and the second TA value, respectively.

[0107] In some scenarios or implementations, the base station 104 sends a third TA command including a first new TA value to the UE 102 via TRP 107-1 or TRP 107-2 to update the first TA value. In some implementations, the third TA command is a MAC control element (CE). The UE 102 applies the first new TA value for the first UL synchronization and restarts the first TAT of the UE 102 in response to receiving the third TA command. The base station 104 restarts the first TAT of the base station 104 in response to sending the third TA command. In some scenarios or implementations, the base station 104 sends a fourth TA command including a second new TA value to the UE 102 via TRP 107-1 or TRP 107-2 to update the second TA value. In some implementations, the fourth TA command is a MAC CE. The UE 102 applies the second new TA value for the second UL synchronization and restarts the second TAT in response to receiving the fourth TA command. In some scenarios or implementations, the base station 104 sends a single TA command including the first new TA value and the second new TA value to the UE 102 via the TRP 107-1 or the TRP 107-2 to update the first TA value and the second TA value, respectively. In some implementations, the single TA command is a new or existing MAC control element (CE) (e.g., as defined in 3GPP specification 38.321 V17.1.0).

[0108] In some implementations, TRP 107-1 generates timing information based on UL transmissions received from UE 102 and sends the timing information to base station 104. In some examples, the timing information indicates a propagation delay or a propagation delay offset. Based on the timing information received from TRP 107-1, base station 104 determines whether to update the first TA value. In some implementations, if the propagation delay or the propagation delay offset 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 offset is less than a second threshold, base station 104 determines not to update the first TA value. In some implementations, if base station 104 determines to update the first TA value, base station 104 generates a first new TA value. In some implementations, TRP 107-2 generates timing information based on UL transmissions received from UE 102 and sends the timing information to base station 104. In some examples, the timing information indicates a propagation delay or a propagation delay offset. Based on the timing information received from TRP 107-2, base station 104 determines whether to update the second TA value. In some implementations, if the propagation delay or the propagation delay offset is greater than or equal to the third threshold, the base station 104 determines to update the second TA value. Otherwise, if the propagation delay or the propagation delay offset is less than the fourth threshold, the base station 104 determines not to update the first TA value. In some implementations, if the base station 104 determines to update the second TA value, the base station 104 generates a second new TA value. Depending on the implementation, the first, second, third, and fourth thresholds are the same or different.

[0109] Go to Figure 5B, scenario 500B is similar to scenario 500A, except as described below. In scenario 500B, base station 104 sends 549, 551 RRC reconfiguration messages to UE 102 via TRP 107-1, and the RRC reconfiguration message includes DL configuration parameters for DL ​​communication with base station 104 via TRP 107-2. In some implementations, base station 104 includes UL configuration parameters for UL communication with base station 104 via TRP 107-1 in the RRC reconfiguration message (e.g., to configure or enable DL communication with base station 104 via TRP 107-2). In some implementations, base station 104 includes the DL configuration parameters in a CellGroupConfig IE and includes the CellGroupConfig IE in the RRC reconfiguration message. In some implementations, base station 104 includes the DL configuration parameters in a BWP-DownlinkDedicated IE and includes the BWP-DownlinkDedicated IE in the RRC reconfiguration message. The RRC reconfiguration message of events 549, 551 is similar to the RRC reconfiguration message of events 548, 550, except that the base station 104 excludes or avoids including UL configuration parameters for UL communication with the base station 104 via TRP 107-2 in the RRC reconfiguration message of events 549, 551. Instead, the base station 104 sends 578, 580 another RRC reconfiguration message to the UE 102 via TRP 107-1, which includes UL configuration parameters for UL communication with the base station 104 via TRP 107-2. In response, the UE 102 sends 582, 584 an RRC reconfiguration complete message to the base station 104 via TRP 107-1. In some implementations, the base station 104 includes the UL configuration parameters in the CellGroupConfig IE and includes the CellGroupConfig IE in the RRC reconfiguration message of events 578, 580. In some implementations, the base station 104 includes the UL configuration parameters in a BWP-UplinkDedicated IE and includes the BWP-UplinkDedicated IE in the RRC reconfiguration message.

[0110] Figure 5B549, 551, 552, 554, 556, 578, 580, 582, and 584 are collectively referred to as a TRP configuration process 596B. After receiving the RRC reconfiguration message at event 538, performing the CSI resource configuration and CSI reporting process 594, or after performing the TRP configuration process 596B with the base station 104, the UE 102 receives 562, 564 RS from the base station 104 via the TRP 107-2. After performing the TRP configuration process 596A with the base station 104, the UE 102 performs 598 a random access process with the base station 104 via the TRP 107-2.

[0111] Next reference Figure 5C , scenario 500C is similar to scenarios 500A and 500B, with the differences being as described below.

[0112] After sending 549, 550 the RRC reconfiguration message or receiving 552, 554 the RRC reconfiguration complete message, the base station 104 sends 579, 581 another RRC reconfiguration message to the UE 102 via TRP 107-2, the other RRC reconfiguration message including UL configuration parameters for UL communication with the base station 104 via TRP 107-2. The RRC reconfiguration messages of events 579, 581 are similar to the RRC reconfiguration messages of events 578, 580, except that the base station 104 sends 579, 581 the RRC reconfiguration to the UE 102 via TRP 107-2 instead of TRP 107-1.

[0113] Figure 5C Boxes 549, 551, 552, 554, 556, 579, 581, 582, and 584 are collectively referred to as the TRP configuration process 596C.

[0114] Next reference Figure 5D , scenario 500D is similar to scenarios 500A, 500B, and 500C, with the differences being as described below.

[0115] After UE 102 performs a TRP configuration procedure 596A, 596B, or 596C with base station 104, UE 102 initiates 599 a random access procedure. In response to the initiation, UE 102 sends 566, 568 a second random access preamble to base station 104 via TRP 107-2. In response, base station 104 sends 571, 573 a second random access response to UE 102 via TRP 107-1 instead of TRP 107-2.

[0116] Next reference Figure 5E, scenario 500E is similar to scenarios 500A, 500B, 500C, and 500D, with the differences being as described below.

[0117] In some implementations, after receiving the RRC reconfiguration complete message at event 554, similar to events 558 and 560, base station 104 sends 559, 561 a PDCCH instruction to UE 102 via TRP 107-1 so that UE 102 initiates a random access process 598 or 599 with base station 104 via TRP 107-2.

[0118] FIG. 6A to FIG. 14 1 is a flow chart depicting an example method that a RAN node (e.g., base station 104 or 106 or DU 174) may implement to enable communication of a UE (e.g., UE 102) through multiple TRPs. In some examples, the first TRP and the second TRP described below are 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.

[0119] First go to Fig. 6A , a RAN node (e.g., base station 104 / 106 or DU 174) implements example method 600A to enable communication of a UE (e.g., UE 102) through multiple TRPs.

[0120] Method 600A begins at block 602, in which the RAN node performs DL and UL communications with the UE via a first TRP (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, 562, 564). At block 604, the RAN node sends to the UE via the first TRP DL configuration parameters for DL ​​communications with the UE via a second TRP (e.g., events 548, 550, 596A, 549, 551, 596B, 596C). At box 606, the RAN node performs DL and UL communications with the UE through the first TRP, and performs DL communications with the UE through the second TRP according to the DL configuration parameters (e.g., events 556, 596A, 596B, 596C). At box 608, the RAN node sends UL configuration parameters for UL communications with the UE through the second TRP to the UE through the first TRP or the second TRP (e.g., events 548, 550, 549, 551, 578, 580, 596B, 579, 581, 596C). The process then proceeds to box 610 and / or box 612. At box 610, the RAN node sends a random access trigger command to the UE through the first TRP to trigger the UE to send a random access preamble code to the second TRP (e.g., events 548, 550, 558, 560, 596A, 578, 580, 596B). At box 612, the RAN node sends a random access trigger command to the UE through the second TRP to trigger the UE to send a random access preamble to the second TRP (e.g., events 579, 581, 596C, 559, 561). At box 614, the RAN node receives the random access preamble from the UE through the second TRP (e.g., events 566, 568, 598, 599). Then, the process proceeds to box 616 and / or box 618. At box 616, the RAN node sends a random access response to the UE through the first TRP in response to the random access preamble (e.g., events 570, 572, 598). At box 618, the RAN node sends a random access response to the UE through the second TRP in response to the random access preamble (e.g., events 571, 573, 599). At box 620, the RAN node performs DL and UL communication with the UE through the first TRP and the second TRP (e.g., event 576).

[0121] Blocks 608, 610, 612, 614, 616, 618, and 620 are Fig. 6A Collectively referred to as frame 690.

[0122] In some implementations, the random access trigger command is a PDCCH instruction (e.g., events 558, 560, 559, 561). In other implementations, the random access trigger command is an RRC reconfiguration message that includes random access configuration parameters for the UE to send a random access preamble to the RAN node via the second TRP (e.g., events 548, 550, 578, 580, 579, 581).

[0123] Figure 6B Shown with Fig. 6A The method 600A shown in FIG. 6 is similar to the example method 600B, except that the method 600B includes block 607 .

[0124] At block 607, the RAN node determines whether the UE supports multiple UL transmission timings for mTRP operation. If the RAN node determines that the UE supports multiple UL transmission timings for mTRP operation, the flow proceeds to block 690. Otherwise, if the RAN node determines that the UE does not support multiple UL transmission timings for mTRP operation, the flow proceeds to block 622, where the flow ends.

[0125] Next go to Fig. 7A , a base station (e.g., base station 104 or 106) implements example method 700A to enable communication of a UE (e.g., UE 102) through multiple TRPs.

[0126] Method 700A begins at box 702, in which the base station performs DL and UL communications with the UE via a first TRP (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, 562, 564). At box 704, the base station determines to configure the UE to communicate with a second TRP. In some implementations, the base station makes the determination based on a CSI report received from the UE as described above. At box 706, the base station includes DL configuration parameters for DL ​​communications with the UE via the second TRP in a first RRC message in response to the determination (e.g., events 548, 550, 596A). At box 708, the base station determines whether the UE supports multiple UL transmission timings for mTRP operation. If the base station determines that the UE supports multiple UL transmission timings for mTRP operation, the process proceeds to block 710. At block 710, the base station includes UL configuration parameters for UL communication with the UE via the second TRP in the first RRC message (e.g., events 548, 550, 596A). Otherwise, if the base station determines that the UE does not support multiple UL transmission timings for mTRP operation, the process skips block 710 and proceeds to block 712. At block 712, the base station sends a first RRC message to the UE via the first TRP (e.g., events 548, 550, 596A).

[0127] Blocks 708, 710, and 712 are Fig. 7A They are collectively referred to as frame 790.

[0128] In some implementations, the base station includes the first UL configuration parameter in the second RRC message instead of the first RRC message, and sends the second RRC message to the UE via the first TRP or the second TRP (e.g., events 578, 580, 596B, 579, 581, 596C). In such implementations, the first RRC message does not include the first UL configuration parameter (e.g., events 549, 551).

[0129] Figure 7B Shown with Fig. 7A The method 700A shown in FIG. 7 is similar to the example method 700B, except that the method 700B includes blocks 707 , 714 , and 716 .

[0130] At block 707, the base station determines whether the second TRP applies the same UL transmission timing as the first TRP. If the base station determines that the second TRP does not apply the same UL transmission timing as the first TRP, the process proceeds to block 790. Otherwise, if the base station determines that the second TRP applies the same UL transmission timing as the first TRP, the process proceeds to block 714. At block 714, the base station includes in the first RRC message a second UL configuration parameter for UL communication with the UE through the second TRP. At block 716, the base station sends the first RRC message to the UE via the first TRP.

[0131] In some implementations, the base station includes the second UL configuration parameter in the second RRC message instead of the first RRC message, and sends the second RRC message to the UE via the first TRP or the second TRP (e.g., events 549, 551, 578, 580, 596B, 579, 581, 596C). In some implementations, at least some of the first UL configuration parameter and the second UL configuration parameter are the same and have the same or different values. In some implementations, the first UL configuration parameter and the second UL configuration parameter include different parameters.

[0132] Next go to Fig. 8A , a RAN node (e.g., base station 104 / 106 or DU 174) implements example method 800A to enable communication of a UE (e.g., UE 102) through multiple TRPs.

[0133] Method 800A begins at block 802, where a RAN node generates reference signals (RS) 1, ..., N (e.g., events 562, 564), where N is an integer and greater than one. In some implementations, the RS includes SSBs and / or CSI-RS for the UE and / or other UEs to perform random access procedures and CSI measurements and reports. At block 804, the RAN node sends RS 1, ..., M and M+1, ..., N (e.g., events 562, 564) through a first TRP and a second TRP, respectively, where M is an integer and 0≤M≤N. At block 806, the RAN node determines whether to trigger the UE to send a random access preamble to the first TRP or the second TRP. If the RAN node determines to trigger the UE to send a random access preamble to the first TRP, the process proceeds to block 808. At block 808, the RAN node sends a random access trigger command for the first TRP to the UE to trigger the UE to send a first random access preamble to the first TRP. In some implementations, the RAN node includes an RS index identifying the RS in RS 1, ..., M in the first random access preamble to trigger the UE to send a random access preamble to the first TRP.

[0134] Otherwise, if the RAN node determines to trigger the UE to send a random access preamble to the second TRP, the flow proceeds to block 810. At block 810, the RAN node sends a random access trigger command for the second TRP to the UE to trigger the UE to send a random access preamble to the second TRP (e.g., events 548, 550, 558, 560, 596A, 578, 580, 596B, 579, 581, 596C, 559, 561). In some implementations, the RAN node includes an RS index identifying an RS in RS M+1, ..., N in the second random access preamble to trigger the UE to send a random access preamble to the second TRP.

[0135] Figure 8B Shown with Fig. 8A The method 800A shown in FIG. 8 is similar to the example method 800B, except that the method 800B includes blocks 803 and 805 instead of blocks 802 and 804.

[0136] Method 800B begins at block 803, where the RAN node sends a first interface message to a first TRP to command the first TRP to send RS 1, ..., M. In some implementations, the first interface message includes a configuration for each of RS 1, ..., M. The first TRP sends RS 1, ..., M in response to or in accordance with the first interface message or configuration. At block 805, the RAN node sends a second interface message to a second TRP to command the second TRP to send RS M+1, ..., N. In some implementations, the second interface message includes a configuration for each of RS 1, ..., M. The second TRP sends RS 1, ..., M and M+1, ..., N in accordance with the second interface message or configuration (e.g., events 562, 564).

[0137] Next go to Fig. 9 , a base station (e.g., base station 104 or 106) implements example method 900 to enable communication of a UE (e.g., UE 102) through multiple TRPs.

[0138] Method 900 begins at block 902, where a base station performs DL and UL communications with a UE via a first TRP (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, 562, 564). At block 904, the base station determines to configure the UE to communicate with a second TRP. In some implementations, the base station makes the determination based on a CSI report received from the UE as described above. At box 906, the base station includes UL configuration parameters for UL communication with the UE via the second TRP in the first RRC message in response to the determination (e.g., events 548, 550, 596A, 578, 580, 596B, 579, 581, 596C). In some implementations, the base station includes DL configuration parameters for DL ​​communication with the UE via the second TRP in the first RRC message (e.g., events 548, 550, 596A). In other implementations, the base station sends a second RRC message including the DL configuration parameters to the UE (e.g., events 549, 551, 596B).

[0139] At box 908, the base station determines whether to (immediately) activate the UE's UL transmission through the second TRP. If the base station determines to (immediately) activate the UE's UL transmission to the second TRP, the process proceeds to box 910. At box 910, the base station includes an activation indication of the second TRP in the first RRC message, wherein the activation indication indicates that the UE sends a random access preamble code through the second TRP (e.g., events 548, 550, 596A, 578, 580, 596B, 579, 581, 596C). Otherwise, if the base station determines not to (immediately) activate UL transmission to the second TRP, the process skips box 910 and proceeds to box 912. At box 912, the base station sends a first RRC message to the UE (e.g., events 548, 550, 596A, 578, 580, 596B, 579, 581, 596C).

[0140] In some implementations, the base station sends a first RRC message to the UE via a first TRP (e.g., events 548, 550, 596A, 578, 580, 596B). In other implementations, the base station sends a first RRC message to the UE via a second TRP (e.g., events 579, 581, 596C).

[0141] Next go to Fig.10 , a RAN node (e.g., base station 104 / 106 or DU 174) implements example method 1000 to enable communication of a UE (e.g., UE 102) through multiple TRPs.

[0142] Method 1000 begins at block 1002, where a RAN node performs DL and UL communications with a UE via a first TRP (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, 562, 564). At block 1004, the RAN node determines to configure the UE to communicate with a second TRP. In some implementations, the RAN node makes the determination based on a CSI report received from the UE as described above. At box 1006, the RAN node sends UL configuration parameters for UL communication with the UE via the second TRP in response to the determination (e.g., events 548, 550, 596A, 578, 580, 596B, 579, 581, 596C). At box 1008, the RAN node determines whether the UE is synchronized with the RAN node via the second TRP. If the RAN node determines that the UE is not synchronized with the RAN node via the second TRP, the process proceeds to box 1010. At box 1010, the RAN node avoids performing UL communication with the UE via the second TRP. At box 1012, the RAN node performs a random access procedure with the UE to adjust the UL transmission timing of the UE for UL communication with the UE via the second TRP (e.g., events 598, 599). At box 1014, the RAN node performs UL communication with the UE via the second TRP (e.g., event 576). If the RAN node determines that the UE is synchronized with the RAN node via the second TRP, the process skips boxes 1010 and 1012 and proceeds to box 1014.

[0143] In some implementations, the RAN node sends a random access trigger command to the UE so that the UE initiates or performs a random access procedure with the RAN node, as described above.

[0144] Next go to Fig.11A , a RAN node (e.g., base station 104 or 106 or DU 174) implements example method 1100A to enable communication of a UE (e.g., UE 102) through multiple TRPs.

[0145] Method 1100A begins at block 1102, where the RAN node sends RS 1, ..., M and M+1, ..., N using a first TRP and a second TRP, respectively (e.g., similar to blocks 802 and 804 or blocks 803 and 805). N is an integer and greater than one, and M is an integer and 0≤M≤N. In some implementations, the RS includes SSBs and / or CSI-RS for the UE and / or other UEs to perform random access procedures and CSI measurements and reports. At block 1104, the RAN node receives a random access preamble from the UE (e.g., events 566, 568, 598, 599). At block 1106, the RAN node determines whether the random access preamble is received via the first TRP or the second TRP. If the RAN node determines that the random access preamble is received via the first TRP, the process proceeds to block 1108, where the RAN node sends a random access response to the UE via the first TRP (e.g., events 570, 572, 598). Otherwise, if the RAN node determines that a random access preamble is received via the second TRP, the process proceeds to box 1110, in which the RAN node sends a random access response to the UE via the second TRP (e.g., events 571, 573, 599).

[0146] Blocks 1106, 1108, and 1110 are Fig.11A The collective name is frame 1190.

[0147] Fig. 11B Shown with Fig.11A The method 1100A shown in FIG. 1 is similar to the example method 1100B, except that the method 1100B includes blocks 1105 and 1112 .

[0148] At block 1105, the RAN node determines whether the random access preamble is a dedicated preamble (e.g., the random access preamble is dedicated to the UE). If the RAN node determines that the random access preamble is not a dedicated preamble, the flow proceeds to block 1190. If the RAN node determines that the random access preamble is not a dedicated preamble, the flow proceeds to block 1112, in which the RAN node sends a random access response to the UE via the first TRP or the second TRP (e.g., events 570, 572, 598, 571, 573, 599). In some implementations, if a PDCCH opportunity on the first TRP is available earlier than a PDCCH opportunity on the second TRP, the RAN node determines to send a random access response to the UE via the first TRP at block 1112. In some implementations, if a PDCCH opportunity on the second TRP is available earlier than a PDCCH opportunity on the first TRP, the RAN node determines to send a random access response to the UE via the second TRP at block 1112. In other implementations, the RAN node always sends a random access response to the UE at box 1112 via the first TRP instead of the second TRP.

[0149] Next go to Fig.12 , a DU (e.g., DU 174) implements example method 1200 to enable communication of a UE (e.g., UE 102) through multiple TRPs.

[0150] Method 1200 begins at block 1202, in which the DU performs DL and UL communications with the UE via a first TRP (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, 562, 564). At block 1204, the DU determines to configure the UE to communicate with a second TRP. In some implementations, the DU makes the determination based on a CSI report received from the UE as described above. At block 1206, the DU determines whether the UE supports multiple UL transmission timings for mTRP operation. If the DU determines that the UE does not support multiple UL transmission timings for mTRP operation, the process proceeds to block 1208. At box 1208, the DU includes in the DU to CU message DL configuration parameters for DL ​​communications with the UE via the second TRP. The DU avoids including in the DU to CU message UL configuration parameters for UL communications with the UE via the second TRP. If the DU determines that the UE supports multiple UL transmission timings for mTRP operation, the process proceeds to box 1210. At box 1208, the DU includes in the DU to CU message DL and UL configuration parameters for DL ​​and UL communications with the UE via the second TRP. The process proceeds from box 1208 or box 1210 to box 1212. At box 1212, the DU sends a DU to CU message to the CU.

[0151] In some implementations, the DU to CU message is a F1AP message (e.g., a UE Context Modification Required message or a UE Context Modification Response message). FIG. 5A to FIG. 5E described.

[0152] Next go to Fig.13 , a RAN node (e.g., base station 104 / 106 or DU 174) implements example method 1300 to enable communication of a UE (e.g., UE 102) through multiple TRPs.

[0153] Method 1300A begins at block 1302, where the RAN node performs DL and UL communications with the UE via a first TRP (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, 562, 564). At block 1304, the RAN determines whether the UE supports multiple UL transmission timings for mTRP operation. If the RAN determines that the UE supports multiple UL transmission timings for mTRP operation, the process proceeds to block 1306. At block 1306, the RAN node implements mTRP communications for DL ​​and UL with the UE. In some implementations, the RAN node performs at block 1306 for FIG. 5A to FIG. 5E Describes the events to configure the mTRP communications for DL ​​and UL with TRP 107-1 and TRP 107-2.

[0154] If the DU determines that the UE does not support multiple UL transmission timings for mTRP operation, the flow proceeds to block 1308 or 1310. At block 1308, the RAN node refrains from implementing mTRP communications with the UE. At block 1310, the RAN node implements mTRP communications only for the DL of the UE. That is, the RAN node refrains from implementing mTRP communications for the UL of the UE at block 1310. In some implementations, the RAN node performs a Figures 5A to 5E Describes the events to configure the mTRP communication with the DL of TRP 107-1 and TRP 107-2.

[0155] Next go to Fig.14 , a RAN node (e.g., base station 104 / 106 or DU 174) implements example method 1400 to enable communication of a UE (e.g., UE 102) through multiple TRPs.

[0156] Method 1400 begins at block 1402, where a RAN node performs DL and UL communications with a UE via a first TRP and a second TRP (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, 562, 564, 598, 599, 576). At block 1404, the RAN node sends a first TA value and a second TA value to the UE for communication with the first TRP and the second TRP, respectively. At block 1406, the RAN node schedules the UE to send a first plurality of UL transmissions to the RAN node via the first TRP using a first set of HARQ process IDs. At box 1408, the RAN node uses a second set of HARQ process IDs to schedule the UE to send a second plurality of UL transmissions to the RAN node via a second TRP.

[0157] In some implementations, the RAN node selects a HARQ process ID from a first set of HARQ process IDs and generates a DCI including the selected HARQ process ID, generates a CRC for the DCI, scrambles the DCI for the C-RNTI of the UE, and sends the DCI and the scrambled CRC to the UE on a PDCCH to schedule each of the first plurality of UL transmissions. In some implementations, the RAN node selects a HARQ process ID from a second set of HARQ process IDs and generates a DCI including the selected HARQ process ID, generates a CRC for the DCI, scrambles the DCI for the C-RNTI of the UE, and sends the DCI and the scrambled CRC to the UE on a PDCCH to schedule each of the second plurality of UL transmissions.

[0158] Next go to Fig.15 , a UE (e.g., UE 102) implements example method 1500 to communicate with a base station (e.g., base station 104 or 106) via multiple TRPs.

[0159] Method 1500 begins at box 1502, in which the UE performs DL and UL communications with a base station via a first TRP (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, 562, 564). At box 1503, the UE maintains a first UL synchronization with the first TRP (e.g., event 520). At box 1504, the UE receives a first RRC message from the base station, the first RRC message including DL configuration parameters for DL ​​communications with the base station via a second TRP (e.g., events 548, 550, 596A, 549, 551, 596B, 596C). At box 1506, the UE performs DL and UL communications with the base station through the first TRP, and performs DL communications with the base station through the second TRP according to the DL configuration parameters (e.g., events 556, 596A, 596B, 596C). At box 1508, the UE receives a second RRC message from the base station, which includes UL configuration parameters for UL communication with the base station through the second TRP (e.g., events 548, 550, 549, 551, 578, 580, 596B, 579, 581, 596C). The process then proceeds to box 1510 and / or box 1512. At box 1510, the UE receives a random access trigger command from the first TRP to trigger the UE to send a random access preamble code to the second TRP (e.g., events 550, 558, 560, 596A, 578, 580, 596B). At box 1512, the UE receives a random access trigger command from the second TRP to trigger the UE to send a random access preamble to the second TRP (e.g., events 581, 596C, 561). At box 1514, the UE sends a random access preamble to the second TRP (e.g., events 566, 598, 599). The process then proceeds to box 1516 or 1518. At box 1516, the UE receives a random access response from the first TRP in response to the random access preamble (e.g., events 572, 598). At box 1518, the UE receives a random access response from the second TRP in response to the random access preamble (e.g., events 573, 599). At box 1519, the UE maintains a second UL synchronization with the second TRP while maintaining a first UL synchronization with the first TRP (e.g., events 520, 574). At box 1520, the UE performs DL and UL communications with the base station through the first TRP and the second TRP (e.g., event 576).

[0160] In some implementations, the random access trigger command is a PDCCH instruction (e.g., events 558, 560, 559, 561). In other implementations, the random access trigger command is an RRC reconfiguration message, which includes random access configuration parameters for the UE to send a random access preamble to the base station via the second TRP (e.g., events 548, 550, 578, 580, 579, 581).

[0161] In some implementations, the UE applies the first TA value and the second TA value to maintain the first UL synchronization and the second UL synchronization, respectively. In some implementations, the random access response at block 1516 or 1518 includes a TA command, the TA command including the second TA value. In some implementations, the UE applies the first TA value and the second TA value at block 1520 to send the first UL transmission and the second UL transmission to the first TRP and the second TRP, respectively.

[0162] Next go to Fig.16A , a UE (e.g., UE 102) implements example method 1600A to communicate with a base station (e.g., base station 104 or 106) via multiple TRPs.

[0163] Method 1600A begins at box 1602, in which the UE performs DL and UL communications with a base station via a first TRP (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, 562, 564). At box 1603, the UE maintains a first UL synchronization with the first TRP (e.g., event 520). At box 1604, the UE receives a first RRC message from the base station, the first RRC message including UL configuration parameters for UL communications with the base station via a second TRP (e.g., events 548, 550, 596A, 578, 580, 596B, 579, 581, 596C). At box 1606, the UE determines whether the first RRC message includes random access configuration parameters for random access with the second TRP. If the UE determines that the first RRC message includes random access configuration parameters for random access with the second TRP, the process proceeds to box 1608. At box 1608, the UE avoids performing UL communication with the base station through the second TRP. At box 1610, the UE performs a random access procedure with the base station to perform UL synchronization with the base station through the second TRP (e.g., events 566, 568, 570, 572, 574, 598, 571, 573, 599). At box 1611, the UE maintains a second UL synchronization with the second TRP while maintaining a first UL synchronization with the first TRP (e.g., events 520, 574). Otherwise, if the UE determines that the first RRC message does not include random access configuration parameters for random access with the second TRP, the process skips boxes 1608 and 1610 and proceeds to box 1612. At box 1612, the UE performs UL communication with the base station via a second TRP (e.g., event 576).

[0164] In some implementations, the first RRC message includes DL configuration parameters for communication with the base station through the second TRP in the first RRC message (e.g., events 548, 550, 596A). In other implementations, the UE receives the second RRC message including the DL configuration parameters instead of the first RRC message (e.g., events 549, 551, 596B, 596C). The UE performs DL communication with the base station through the second TRP according to the DL configuration parameters.

[0165] Fig. 16B Shown with Fig.16A The example method 1600B is similar to the scenario 1600A shown in FIG. 1 , except that the method 1600B includes block 1607 instead of block 1606 .

[0166] At block 1607, the UE determines whether the first RRC message indicates that UL synchronization is required for communication with the base station through the second TRP. If the UE determines that the first RRC message indicates that UL synchronization is required for communication with the base station through the second TRP, the process proceeds to block 1608. Otherwise, if the UE determines that (i) the first RRC message does not indicate that UL synchronization is required for communication with the base station through the second TRP or (ii) the first RRC message indicates that UL synchronization is not required for communication with the base station through the second TRP, the process skips blocks 1608 and 1610 and proceeds to block 1612.

[0167] In some implementations, the first RRC message includes a configuration (e.g., a field or IE (e.g., an RRC version 18 field or IE)) that indicates to perform UL synchronization (e.g., indicating that UL synchronization is required) or to implement operation of two TA values. In some implementations, the UE initiates a random access procedure 598 in response to the configuration before sending an UL transmission (e.g., channel state information (CSI), a sounding reference signal (SRS), a PUCCH transmission, and / or a PUSCH transmission) to the base station via the second TRP. In some implementations, if the RRC reconfiguration message does not include the field or IE, the UE does not initiate a random access procedure and sends an UL transmission to the base station via the second TRP. In another implementation, the UE 102 avoids sending an UL transmission to the base station via the second TRP in response to the field or IE. In such a case, the UE 102 does not send a random access preamble to the base station 104 via the second TRP until a PDCCH instruction is received from the base station (e.g., events 558, 560, 559, 561).

[0168] Combination Fig.15 The examples and implementations discussed can also be applied to Fig.16A and Fig. 16B .

[0169] Next go to Fig.17A , a UE (e.g., UE 102) implements example method 1700A to communicate with a base station (e.g., base station 104 or 106) via multiple TRPs.

[0170] Method 1700A begins at box 1702, in which the UE performs DL and UL communications with a base station via a first TRP (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, 562, 564). At box 1703, the UE maintains a first UL synchronization with the first TRP (e.g., event 520). At box 1704, the UE receives UL configuration parameters from the base station for UL communications with the base station via a second TRP (e.g., events 548, 550, 596A, 578, 580, 596B, 579, 581, 596C). At block 1706, the UE receives a random access trigger command from the base station (eg, events 558, 560, 559, 561). In some implementations, the random access trigger command is a PDCCH order.

[0171] At box 1708, the UE determines whether the random access trigger command is received via the first TRP or the second TRP. If the UE determines that the random access trigger command is received via the first TRP or the second TRP, the process proceeds to box 1710. At box 1710, the UE avoids performing UL communication with the base station through the second TRP. At box 1712, the UE performs a random access procedure with the base station to perform a second UL synchronization with the base station through the second TRP (e.g., events 566, 568, 570, 572, 574, 598, 571, 573, 599). At box 1713, the UE maintains a second UL synchronization with the second TRP while maintaining a first UL synchronization with the first TRP (e.g., events 520, 574). Otherwise, if the UE determines that the first RRC message does not include random access configuration parameters for random access with the second TRP, the process skips boxes 1710 and 1712 and proceeds to box 1714. At box 1714, the UE performs UL communication with the base station via the second TRP (e.g., event 576).

[0172] Fig. 17B Shown with Fig.17A The example method 1700B is similar to the scenario 1700A shown in FIG. 17 , except that the method 1700B includes box 1709 instead of box 1708 .

[0173] At block 1709, the UE determines whether the random access trigger command indicates the first TRP or the second TRP. If the UE determines that the random access trigger command indicates the first TRP, the process proceeds to block 1710. Otherwise, if the UE determines that the random access trigger command indicates the second TRP, the process skips blocks 1710 and 1712 and proceeds to block 1714.

[0174] Combined with Figure 16, Fig.16A and Fig. 16B The examples and implementations discussed can also be applied to Fig.17A and Fig. 17B .

[0175] Reference now Fig.18 , a UE (e.g., UE 102) implements example method 1800 to communicate with a base station (e.g., base station 104 or 106) via multiple TRPs.

[0176] Method 1800 begins at box 1802, in which the UE performs DL and UL communications with a base station via a first TRP (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, 562, 564). At box 1803, the UE maintains a first UL synchronization with the first TRP (e.g., event 520). At box 1804, the UE receives UL configuration parameters from the base station for UL communications with the base station via a second TRP (e.g., events 548, 550, 596A, 578, 580, 596B, 579, 581, 596C). At block 1806, the UE receives random access configuration parameters from the base station for random access with the base station via the second TRP (e.g., events 548, 550, 596A, 578, 580, 596B, 579, 581, 596C, 508, 510). At block 1808, the UE avoids performing UL communication with the base station via the second TRP.

[0177] At box 1810, the UE determines whether the UL configuration parameters include an access activation indication for the second TRP. If the UE determines that the UL configuration parameters do not include an access activation indication for the second TRP, the process proceeds to box 1812. Otherwise, if the UE determines that the UL configuration parameters include an access activation indication for the second TRP, the process proceeds to box 1814. At box 1812, the UE attempts to receive a random access trigger command from the base station for triggering the UE to send a random access preamble code to the base station through the second TRP. In some implementations, the UE monitors the PDCCH using the UE's C-RNTI to attempt to receive the random access trigger command at box 1812.

[0178] At box 1814, the UE determines whether the UE receives a random access trigger command for triggering the UE to send a random access preamble to the second TRP (e.g., events 558, 560, 559, 561). If the UE determines that it has received a random access trigger command for triggering the UE to send a random access preamble to the second TRP, the process proceeds to box 1816. Otherwise (e.g., if the UE does not receive a random access trigger command for triggering the UE to send a random access preamble to the second TRP in the current attempt), the process returns to box 1812. At box 1816, the UE performs a random access procedure with the base station to perform a second UL synchronization with the base station through the second TRP (e.g., events 598, 599). At box 1817, the UE maintains a second UL synchronization with the second TRP while maintaining a first UL synchronization with the first TRP (e.g., events 520, 574). At box 1818, the UE performs UL communication with the base station through the second TRP (e.g., event 576).

[0179] In some implementations, the UE receives DL configuration parameters from the base station for communicating with the base station via the second TRP (e.g., events 548, 550, 596A, 549, 551, 596B, 596C). In one implementation, the UE begins applying the DL configuration parameters to communicate with the base station via the second TRP without waiting for the random access procedure to be completed (e.g., event 556). In other implementations, the UE begins applying the DL configuration parameters to communicate with the base station via the second TRP after completing the random access procedure (e.g., event 576).

[0180] The examples and implementations discussed above in conjunction with 15 to 17B are also applicable to Fig.18 .

[0181] Reference now Fig.19 , a UE (e.g., UE 102) implements example method 1900 to communicate with a base station (e.g., base station 104 or 106) via multiple TRPs.

[0182] Method 1900 begins at block 1902, where the UE performs DL and UL communications with a 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, 562, 564). At block 1904, the UE receives a first TA value and a second TA value from the base station (e.g., events 570, 572, 598, 571, 573, 599). At block 1906, the UE maintains first UL synchronization and second UL synchronization with the base station based on the first TA value and the second TA value, respectively. At block 1908, the UE uses a first set of HARQ processes and a first TA value to send a first plurality of UL transmissions to the base station via a first TRP. At box 1910, the UE uses a second set of HARQ processes and a second TA value to send a second plurality of UL transmissions to the base station via a second TRP.

[0183] The examples and implementations discussed above in conjunction with 15 to 18 are also applicable to Fig.19 .

[0184] The following description can be applied to the above description.

[0185] Some further implementations or descriptions related to a UE (eg, UE 102) performing a random access procedure and / or performing multi-TA operation are described below.

[0186] In some implementations, each TRP (e.g., TRP 107-1, TRP 107-2, TRP 107-3, TRP 108-1, and / or TRP 108-2) is associated with or identified by a TRP identifier. In some implementations, a base station (e.g., base station 104 or 106) includes the TRP identifier in a UL configuration, and the base station sends the UL configuration to a UE (e.g., UE 102) for UL transmission via the TRP identified by the TRP identifier. In some implementations, the UL configuration includes a DCI sent on a PDCCH, and / or a PUSCH configuration, a PUCCH configuration, and / or an SRS configuration included in an RRC message (e.g., an RRC reconfiguration message or an RRC recovery message) sent by the base station to the UE. In some implementations, the UL transmission includes a PUSCH transmission, a PUCCH transmission, and / or an SRS transmission. In some implementations, the base station includes the TRP identifier in a DL configuration that the base station sends to the UE 102 for DL ​​transmission via the TRP identified by the TRP identifier. In some implementations, the DL configuration includes DCI sent on the PDCCH, and / or a CSI resource configuration, a PDSCH configuration, and / or a PDCCH configuration included in an RRC message (e.g., an RRC reconfiguration message or an RRC recovery message) sent by the base station to the UE. In some implementations, the DL transmission includes a CSI-RS transmission, an SSB transmission, a PDSCH transmission, and / or a PDCCH transmission.

[0187] In other implementations, the base station does not send a TRP identifier to the UE, and uses an implicit indication to indicate the TRP to the UE. In some implementations, the implicit indication is one of the following configuration parameters: CORESETPoolIndex, a value or value candidate for CORESETPoolIndex, dataScramblingIdentityPDSCH, dataScramblingIdentityPDSCH2-r16, or PUCCH-ResourceGroup-r16. In such implementations, the UE derives the TRP (identifier) ​​from the implicit indication. In some implementations, the base station sends an RRC message (e.g., an RRC reconfiguration message or an RRC recovery message) including the configuration parameters to the UE.

[0188] In some implementations, the base station configures a first TAG and a second TAG for the UE for UL transmission to the first TRP and the second TRP, respectively. In some implementations, the base station sends a first RRC message and a second RRC message including the first TAG configuration and the second TAG configuration to the UE to configure the first TAG and the second TAG, respectively. In some implementations, the first TAG configuration and the second TAG configuration include a first TAG ID and a second TAG ID to identify the first TAG and the second TAG, respectively. In some implementations, the first TAG configuration and the second TAG configuration include a timer value of a first TAT and a timer value of a second TAT for the first TAG and the second TAG, respectively. In some implementations, 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 implementations, the first and second RRC messages are RRC settings, RRC reconfiguration and / or RRC recovery messages. The UE associates the first TA value and the second TA value with the first TAG and the second TAG, respectively. In some implementations, the first TAG is associated with a first TRP or a first TRP identifier and / or an identifier value. In some implementations, the first TAG is associated with a first service cell operated by the first TRP and configured for the UE. In some implementations, the first TAG is associated with an additional service cell operated by the first TRP and configured for the UE. In some implementations, the base station indicates or configures the association in the first RRC message. In some implementations, the second TAG is associated with a second TRP or a second TRP identifier and / or an identifier value. In some implementations, the second TAG is associated with a first service cell or a non-service cell, and the base station indicates or configures the association in a second RRC message.

[0189] In other implementations, the base station configures a single TAG for the UE for UL transmission to the first TRP and the second TRP. In some implementations, the base station sends a first RRC message (e.g., RRC setup, RRC reconfiguration, and / or RRC recovery message) including a single TAG configuration for configuring the TAG to the UE. In some implementations, the TAG configuration includes a single TAG ID to identify the TAG. In some implementations, the TAG configuration includes a timer value for the first TAT and a timer value for the second TAT. In a further implementation, the TAG configuration includes a timer value for the first TAT, and the base station sends a second RRC message (e.g., RRC setup, RRC reconfiguration, and / or RRC recovery 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 implementations, the TAG is associated with (i) the first TRP or the first TRP identifier and / or identifier value and (ii) the second TRP or the second TRP identifier. In some implementations, the TAG is associated with a first serving cell operated by the first TRP and configured for the UE. In some implementations, the TAG is associated with an additional serving cell operated by a first TRP and configured for the UE. In some implementations, the base station indicates or configures the association in a first RRC message. In some implementations, the TAG is associated with a second TRP or a second TRP identifier and / or identifier value. In some implementations, the TAG is associated with a first serving cell or a non-serving cell, and the base station indicates or configures the association in a second RRC message.

[0190] In some implementations, the base station configures a first serving cell to be associated with a first TRP or a first TRP identifier and / or identifier value. In some implementations, the base station configures a first control resource set (CORESET) associated with the first serving cell or the first TRP. In a further implementation, the base station configures CORESETPoolIndex #0 to identify the first CORESET. In some implementations, the base station sends a third RRC message (e.g., an RRC setup message, an RRC reconfiguration message, or an RRC recovery message) to the UE that configures the first CORESET and / or includes CORESETPoolIndex#0. Therefore, 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 (i.e., from the first TRP) via the first TRP. In some such cases, the UE determines that CORESETPoolIndex #0 indicates a specific TRP (i.e., the first TRP) of the base station.

[0191] In some implementations, the base station configures the first serving cell to be associated with a second TRP or a second TRP identifier and / or an identifier value. In some implementations, the second TAG is associated with a non-serving cell, and the base station indicates or configures the association in a second RRC message. In some implementations, the base station configures the non-serving cell to be associated with a second TRP or a second TRP identifier and / or an identifier value. In some implementations, the base station configures the second CORESET to be associated with the first serving cell, the non-serving cell, or the second TRP. In a further implementation, the base station configures CORESETPoolIndex #1 to identify the second CORESET. In some implementations, the base station sends a third RRC message (e.g., an RRC setup message, an RRC reconfiguration message, or an RRC recovery message) to the UE configuring the second CORESET and / or including CORESETPoolIndex #1. Therefore, 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 (i.e., from the second TRP) via the second TRP. In some such implementations, the UE determines that CORESETPoolIndex #1 indicates a specific TRP (i.e., the second TRP).

[0192] In some implementations, in addition to the TAG ID described above, the base station is further configured with a first ID for identifying a first TA value of the UE. In some implementations, the base station includes the first ID in the RRC message described above. In a further implementation, the base station includes the first ID in the first TA command. In other implementations, the UE derives or determines the first ID and associates the first ID with the first TA value. Similarly, in addition to the TAG ID described above, the base station is further configured with a second ID for identifying a second TA value for the UE. In some implementations, the base station includes the second ID in the RRC message described above. In a further implementation, the base station includes the second ID in the second TA command. In other implementations, the UE derives or determines the second ID and associates the second ID with the second TA value.

[0193] More generally, in some implementations, the base station configures or indicates to the UE a first index for or associated with the first TRP. In some implementations, the UE derives or determines the first index. In some implementations, the first index is one of: (i) a first TRP identifier and / or identifier value, (ii) an ID of a first TAG, (iii) an ID of a first TA value, and / or (iv) an ID of a first TAT.

[0194] More generally, in further implementations, the base station configures or indicates to the UE a second index for / associated with a second TRP. In some implementations, the UE derives the second index. In some implementations, the second index is one of: (i) a second TRP identifier and / or identifier value, (ii) an ID of a second TAG, (iii) an ID of a second TA value, and / or (iv) an ID of a second TAT.

[0195] In some implementations, the UE performs one of the following actions: (i) triggering or performing a contention-based or contention-free RA process associated with a first index; or (ii) triggering or performing a contention-based or contention-free RA process for a first TRP, a first TAG, a first TAT, or a first TA value.

[0196] In some implementations, the UE performs one of the following actions: (i) triggering or performing a contention-based or contention-free RA procedure associated with the second index; or (ii) triggering or performing a contention-based or contention-free RA procedure for a second TRP, a second TAG, a second TAT, or a second TA value. In some such implementations, some examples include a RA procedure that includes the step of sending a RA preamble to the second TRP, as shown in at least FIG. 6, Fig. 7A , Figure 7B , Fig. 8A , Figure 8B and Fig. 9 As described in.

[0197] In some implementations, the UE receives a configuration from a base station for configuring or indicating a first set of RA resources. In some implementations, the first set of RA resources includes a first set of RA preambles and / or a first set of SSB indexes. In further implementations, the first set of RA resources is associated with a first set of SSB indexes. In further implementations, the first set of RA resources includes a first set of UL resources and / or a grant for sending MSG A. In some implementations, the first set of RA resources is associated with or for a first TRP or a first index. In some implementations, the configuration for configuring or indicating the first set of RA resources includes or is associated with the first index.

[0198] In some implementations, the UE receives a configuration from the base station for configuring or indicating a second set of RA resources. In some implementations, the second set of RA resources includes a second set of RA preambles and / or a second set of SSB indexes. In further implementations, the second set of RA resources is associated with a second set of SSB indexes. In further implementations, the second set of RA resources includes a second set of UL resources and / or a grant for sending MSG A. In some implementations, the second set of RA resources is associated with or for a second TRP or a second index. In some implementations, the configuration for configuring or indicating a second group of RA resources includes or is associated with a second index.

[0199] Some examples of configuration for configuring or indicating the first group of RA resources include UL configuration parameters in process 596 A / B / C. Some examples of configuration for configuring or indicating the second group of RA resources include UL configuration parameters in process 596 A / B / C.

[0200] In some cases, when or if a RA procedure is associated with or intended for one of: (a) a first index, (b) a first TRP, (c) a first TAG, (d) a first TA value and / or (e) a first TAT, at least one of the following is true: (i) MSG 0 or a PDCCH instruction of the RA procedure (received by the UE from the base station) indicates the first TRP or is associated with the first TRP, wherein, in some implementations, the RA procedure is a contention-free RA procedure; (ii) MSG 1 or MSG A of the RA procedure (sent by the UE to the base station) indicates the first TRP or is associated with the first TRP, wherein, in some implementations, the UE uses a first group of RA resources to send MSG 1 or MSG A; (iii) MSG 2 or MSG B of the RA procedure (received by the UE from the base station) indicates the first TRP or is associated with the first TRP; (iv) MSG 3 or MSG 4 of the RA procedure (sent by the UE to the base station) (4) indicates a first TRP or is associated with a first TRP; (v) MSG 0 or a PDCCH instruction of a RA process (received by the UE from the base station) indicates a first index or is associated with a first index, wherein, in some implementations, the RA process is a contention-free RA process; (vi) MSG 1 or MSG A of the RA process (sent by the UE to the base station) indicates a first index or is associated with a first index, wherein, in some implementations, the UE uses a first group of RA resources to send MSG 1 or MSG A; (vii) MSG 2 or MSG B of the RA process (received by the UE from the base station) indicates the first index or is associated with the first index; and / or (viii) MSG 3 (sent by the UE to the base station) or MSG 4 (received by the UE from the base station) of the RA process indicates the first index or is associated with the first index.

[0201] In some cases, when or if the RA procedure is associated with or intended for one of: (a) a second index; (b) a second TRP (e.g., an RA procedure including the step of sending an RA preamble to the second TRP, as in at least FIG. 6, Fig. 7A , Figure 7B , Fig. 8A , Figure 8B and Fig. 9); (c) a second TAG; (d) a second TA value; and / or (e) a second TAT, then at least one of the following is true: (i) MSG 0 or a PDCCH instruction of the RA process (received by the UE from the base station) indicates a second TRP or is associated with a second TRP, wherein, in some implementations, the RA process is a contention-free RA process; (ii) MSG 1 or MSG A of the RA process (sent by the UE to the base station) indicates a second TRP or is associated with a second TRP, wherein, in some implementations, the UE uses a second group of RA resources to send MSG 1 or MSG A; (iii) MSG 2 or MSG B of the RA process (received by the UE from the base station) indicates a second TRP or is associated with a second TRP; (iv) MSG 3 of the RA process (sent by the UE to the base station) or MSG 4 of the RA process (received by the UE from the BS) indicates a second TRP or is associated with a second TRP; (v) MSG 1 of the RA process (received by the UE from the base station) (vi) MSG 1 or MSG A (sent by the UE to the base station) of the RA process indicates the second index or is associated with the second index, wherein, in some implementations, the UE uses a second group of RA resources to send MSG 1 or MSG A; (vii) MSG 2 or MSG B (received by the UE from the base station) of the RA process indicates the second index or is associated with the second index; and / or (viii) MSG 3 (sent by the UE to the base station) or MSG 4 (received by the UE from the base station) of the RA process indicates the second index or is associated with the second index.

[0202] The following list of examples reflects the various embodiments that are expressly contemplated.

[0203] Example 1. A method of multiple transmission and reception point (M-TRP) communication in a radio access network (RAN) node, comprising: sending a configuration for initiating a random access procedure to a user equipment (UE), the configuration including an indication of a random access preamble associated with a second TRP of the RAN node; receiving the random access preamble via the second TRP of the RAN node; and sending a random access response including a timing advance (TA) value associated with the second TRP via a first TRP of the RAN node.

[0204] Example 2. The method of Example 1, wherein receiving the configuration further comprises receiving a reference signal (RS) index.

[0205] Example 3. A method as described in Example 1 or 2, wherein the reception of the configuration for initiating the random access process is from the second TRP.

[0206] Example 4. A method as described in any of Examples 1 to 3, wherein the reception of the configuration for initiating the random access process is from the first TRP.

[0207] Generally speaking, the description of one figure in the above-mentioned figures may apply to another figure in the above-mentioned figures. The events or boxes described above may be optional or omitted. For example, the events or boxes with dotted lines in the figures may be optional or omitted. In some cases, if the events or boxes with solid lines in the figures are not necessary, the events or boxes may still be optional or omitted. In some implementations, the boxes in different figures may be combined. In some implementations, "message" is used and "message" can be replaced with "information element (IE)". In some implementations, "IE" is used and "IE" can be replaced with "field". In some implementations, "configuration" can be replaced with "configurations" or "configuration parameters". In some implementations, "use" can be replaced with "according to". "mTRP operation" and "mTRP communication" may be interchangeable. In some implementations, "to the second TRP", "from the second TRP", "with the second TRP" can be replaced with "to the base station through the second TRP", "from the base station through the second TRP", "with the base station through the second TRP", respectively.

[0208] The user device (e.g., UE 102) in which the technology of the present disclosure may be implemented may be any suitable device capable of wireless communication, such as a smart phone, a tablet computer, a laptop computer, a mobile game console, a point of sale (POS) terminal, a health monitoring device, a drone, a camera, a media streaming dongle or another personal media device, a wearable device such as a smart watch, a wireless hotspot, a femtocell, or a broadband router. Further, in some cases, the user device may be embedded in an electronic system such as a head unit of a vehicle or an advanced driver assistance system (ADAS). Further, the user device may operate as an Internet of Things (IoT) device or a mobile Internet device (MID). Depending on the type, the user device may include one or more general-purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0209] Certain embodiments are described in the present disclosure as including logic or multiple components or modules. A module may be a software module (e.g., a code stored on a non-transitory machine-readable medium) or a hardware module. A hardware module is a tangible unit that is capable of performing certain operations and may be configured or arranged in a particular manner. A hardware module may include a dedicated circuit system or logic that is permanently configured (e.g., as a dedicated processor, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC)) to perform certain operations. A hardware module may also include programmable logic or circuit systems (e.g., as contained in a general-purpose processor or other programmable processor) that are temporarily configured by software to perform certain operations. The decision to implement a hardware module in a dedicated and permanently configured circuit system or in a temporarily configured circuit system (e.g., configured by software) may be driven by cost and time considerations.

[0210] When implemented in software, the techniques may be provided as part of an operating system, a library used by multiple applications, a specific software application, etc. The software may be executed by one or more general-purpose processors or one or more special-purpose processors.

Claims

1. A method for multiple transmission and reception point (M-TRP) communication in a user equipment (UE), the method comprising: receiving (596) a configuration for initiating a random access procedure from a radio access network RAN ​​node equipped with a first transmission and reception point TRP and a second TRP, the configuration comprising an indication of a random access preamble associated with the second TRP of the RAN node; sending (566) the random access preamble to the second TRP; and A random access response including a timing advance TA value associated with the second TRP is received (573) from the first TRP.

2. The method of claim 1, wherein: The receiving of the configuration comprises: A physical downlink control channel (PDCCH) command is received.

3. The method of claim 2, wherein: The PDCCH command includes a downlink control indication DCI.

4. A method as claimed in any one of the preceding claims, wherein: The receiving (560) of the configuration also includes receiving a reference signal, RS, index.

5. A method as claimed in any one of the preceding claims, wherein: The receiving (560) of the configuration for initiating a random access procedure comes from the second TRP.

6. The method according to any one of claims 1 to 4, wherein: The reception (561) of the configuration for initiating a random access procedure comes from the first TRP.

7. The method according to any one of the preceding claims, further comprising: DL configuration parameters for downlink DL communication between the UE and the second TRP are received (550) from the first TRP.

8. The method according to any one of the preceding claims, further comprising: UL configuration parameters for uplink UL communication between the UE and the second TRP are received (550) from the first TRP.

9. A method as claimed in any one of the preceding claims, wherein: The indication of the random access preamble comprises an identifier of the random access preamble; the method further comprising: The random access preamble having the indicated identifier is selected.

10. The method according to any one of claims 1 to 8, wherein: The indication of the random access preamble indicates that the UE is to randomly select the random access preamble.

11. The method of any one of the preceding claims, further comprising: In response to receiving the random access response, a TA timer TAT dedicated to the second TRP is started.

12. A method for multiple transmission and reception point (M-TRP) communication in a radio access network (RAN) node, the method comprising: sending a configuration for initiating a random access procedure to a user equipment UE, the configuration comprising an indication of a random access preamble associated with a second TRP of the RAN node; receiving the random access preamble via the second TRP of the RAN node; and A random access response including a timing advance TA value associated with the second TRP is sent via the first TRP of the RAN node.

13. The method of claim 12, wherein: The sending of the configuration comprises: Send PDCCH instructions via the first TRP.

14. The method according to claim 12 or 13, further comprising: (i) DL configuration parameters for downlink DL communication and (ii) UL configuration parameters for uplink UL communication are sent between the UE and the second TRP via the first TRP.

15. A device comprising: a transceiver for communicating via a radio interface; as well as Processing hardware configured to implement a method according to any one of the preceding claims.

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