Enabling measurements for inter-central unit low layer triggered mobility under dual connectivity

Abstract

The present disclosure provides systems, apparatus, equipment, and methods, including computer programs encoded on storage media, for configuring measurements for inter-central-unit low layer triggered mobility under dual connectivity. A radio access node, RAN node (104A), sends a secondary node, SN, request message to a master node, MN (104B). The RAN node (104A) receives a SN answer message from the MN in response to the SN request message, the SN answer message including a low layer triggered mobility, LTM, candidate cell configuration. The RAN node (104A) generates a channel state information, CSI, report configuration based on a reference signal resource configuration. The RAN node (104A) sends the LTM candidate cell configuration, the reference signal resource configuration, and the CSI report configuration associated with the LTM candidate cell to a user equipment, UE (102).

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 563,196, filed March 8, 2024. The disclosure of that U.S. Provisional Patent Application is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to wireless communication, and more specifically, to implementing low-level measurements (e.g., layer 1 measurements) of low-level triggered mobility between central units under dual connectivity. Summary of the Invention

[0004] This background description is provided for the purpose of presenting the general context of this disclosure. The work of the currently attributed inventors (to the extent described in this background section) and aspects of the specification that might not have been considered prior art at the time of filing are neither expressly nor impliedly acknowledged as prior art relative to this disclosure.

[0005] In telecommunications systems, the Packet Data Convergence Protocol (PDCP) sublayer of the radio protocol stack provides services such as the delivery, encryption, and integrity protection of user plane data. For example, the PDCP sublayer defined for the Evolved Universal Terrestrial Radio Access (EUTRA) radio interface (see 3GPP specification TS 36.323) and New Radio (NR) (see 3GPP specification TS 38.323) provides the ordering of Protocol Data Units (PDUs) in the uplink direction (from the user equipment, also known as the User Equipment (UE), to the base station) and in the downlink direction (from the base station to the UE). Furthermore, the PDCP sublayer provides Signaling Radio Bearers (SRBs) and Data Radio Bearers (DRBs) to the Radio Resource Control (RRC) sublayer. Generally, the UE and base station can use SRBs to exchange RRC messages and Non-Access Stratum (NAS) messages, and can use DRBs to transmit data on the user plane.

[0006] UEs can use several types of SRBs and DRBs. When operating in dual connectivity (DC), the cell associated with the base station operating as the primary node (MN) defines the primary cell group (MCG), and the cell associated with the base station operating as the secondary node (SN) defines the secondary cell group (SCG). The so-called SRB1 resource carries RRC messages that, in some cases, include NAS messages on the dedicated control channel (DCCH), while the SRB2 resource supports RRC messages that include recorded measurement information or NAS messages, also on the DCCH but with a lower priority than the SRB1 resource. More generally, SRB1 and SRB2 resources allow the UE and MN to exchange MN-related RRC messages and embed SN-related RRC messages, and can also be referred to as MCG SRBs. SRB3 resources allow the UE and SN to exchange SN-related RRC messages and can be referred to as SCG SRBs. Split SRBs allow the UE to exchange RRC messages directly with the MN via lower-layer resources of the MN and SN. Furthermore, a DRB that uses only the low-level resources of MN can be called an MCG DRB, a DRB that uses only the low-level resources of SN can be called an SCG DRB, and a DRB that uses the low-level resources of both MCG and SCG can be called a split DRB.

[0007] In some scenarios, a UE can concurrently utilize the resources of multiple Radio Access Network (RAN) nodes (e.g., components of a base station or distributed base station) interconnected via backhaul. This type of connection is called Multiple Radio Dual Connectivity (MR-DC) when these network nodes support different Radio Access Technologies (RATs). When the UE operates under MR-DC, one base station operates as the primary node (MN) covering the primary cell (PCell), and another base station operates as the secondary node (SN) covering the primary secondary cell (PSCell). The UE communicates with the MN (via the PCell) and the SN (via the PSCell). In other scenarios, the UE utilizes the resources of one base station at a time. One base station and / or the UE determines that the UE should establish a radio connection with another base station. For example, one base station may determine to hand over the UE to a second base station and initiate a handover procedure.

[0008] When a UE moves within the RAN from the coverage area of ​​one cell to the coverage area of ​​another cell, a serving cell change must be performed for the UE at some point. To perform the serving cell change, the RAN configures the UE to send Layer 3 (L3) measurements. Based on the L3 measurements received from the UE, the RAN sends an RRC reconfiguration message with synchronization (e.g., the RRC reconfiguration message includes...). ReconfigurationWithSyncIE) for changes to the serving cell (e.g., PCell or PSCell). When a UE operates with at least one secondary cell (SCell) and carrier aggregation (CA) with a PCell or PSCell, the RAN must release at least one SCell due to the change in the PCell or PSCell. Serving cell changes involve a complete L2 (and L1) reset, resulting in longer latency, greater overhead, and longer downtime. Therefore, 3GPP has introduced [this measure].

[0009] When a base station in the RAN communicates with a UE via a serving cell, the base station receives one or more Layer 3 (e.g., RRC) measurement results from the UE. The base station consists of a Central Unit (CU) and one or more Distributed Units (DUs). One of the DUs operating the serving cell is the serving DU. Based on the Layer 3 (L3) measurement results, the base station determines and configures LTM candidate cells for LTM cell handover. To configure the LTM candidate cells for the UE, the base station sends an LTM candidate configuration to the UE via RRC signaling. Subsequently, the base station receives one or more Layer 1 (L1) measurement results from the UE. Based on the one or more L1 measurement results, the base station determines that the LTM candidate cells are eligible to become the UE's serving cell. Therefore, the base station sends an LTM cell handover command to the UE to instruct the UE to perform an LTM cell handover to the LTM candidate cells. In response to this LTM cell handover command, the UE performs a cell change from the serving cell to the LTM candidate cells. If the LTM candidate cells are operated by the serving DU, the LTM cell handover is an intra-CU, intra-DU LTM cell handover. If the LTM candidate cell is operated by a candidate DU within a DU, then the LTM cell handover is an LTM cell handover between DUs within a CU. 3GPP has enabled LTM cell handover between DUs within a CU and LTN cell handover between DUs within a CU in Release 18. However, 3GPP has not yet specified LTM cell handover between CUs. Attached Figure Description

[0010] Figure 1A This is a block diagram of an example system according to some embodiments in which the radio access network (RAN) and user equipment can implement the techniques of this disclosure for managing conditional processes associated with secondary nodes (SNs).

[0011] Figure 1B This is another block diagram of an example system according to some embodiments in which the radio access network (RAN) and user equipment can implement the techniques of this disclosure for managing conditional processes associated with an MN or SN.

[0012] Figure 1C According to some embodiments, it is possible to Figure 1A or Figure 1BA block diagram of an example base station operating in the system, including a central unit (CU) and a distributed unit (DU).

[0013] Figure 2A According to some embodiments Figure 1A The block diagram of the UE's example protocol stack for communicating with the base station.

[0014] Figure 2B According to some embodiments Figure 1A A block diagram of an example protocol stack for a UE to communicate with the CU and DU.

[0015] Figure 3 Figure 6E is a signal flow diagram for configuring LTM measurements between CUs according to some embodiments.

[0016] Figure 7A It is shown that, according to some embodiments, it can be generated by an S-SN (e.g., Figures 6A to 6D Example method 700A is implemented in S-SN 104A.

[0017] Figure 7B This is a flowchart of an example method 700B, similar to method 700A according to some embodiments, except that method 700B includes block 709B instead of blocks 709A and 762.

[0018] Figure 8A A method similar to 700A, according to some embodiments, can be generated by an S-SN (e.g., Figures 6A to 6D Example method 800A is implemented by the CU of S-SN 104A.

[0019] Figure 8B This is a flowchart of an example method 800B, which is similar to methods 800A and 700B according to some embodiments, except that method 800B includes block 709B instead of blocks 709A and 762.

[0020] Figure 9A It is shown that, according to some embodiments, it can be made by MN (e.g., Figures 6A to 6D Example method 900A is implemented in MN 104B.

[0021] Figure 9B This is a flowchart of an example method 900B, similar to method 900A according to some embodiments, except that method 900B includes block 907B instead of blocks 907A and 962.

[0022] Figure 10A A method similar to method 900A, according to some embodiments, can be generated by MN (e.g., Figures 6A to 6DExample method 1000A is implemented in the CU of MN 104B.

[0023] Figure 10B This is a flowchart of an example method 1000B, which is similar to methods 1000A and 900B according to some embodiments, except that method 1000B includes block 907B instead of blocks 907A and 962.

[0024] Figure 11 It is shown that, according to some embodiments, it can be generated by a C-SN (e.g., Figures 6A to 6D Example method 1100 implemented in C-SN 106A.

[0025] Figure 12 It is shown that, according to some embodiments, it can be generated by a C-SN (e.g., Figures 6A to 6D Example method 1200 of the CU implementation of C-SN 106A.

[0026] Figure 13A A method similar to 700A, according to some embodiments, can be generated by an S-SN (e.g., Figures 6A to 6D Example method 1300A is implemented in S-SN 104A, except that method 1300A includes boxes 1372, 1374, 1318 and 1324 instead of boxes 762, 764, 718 and 724.

[0027] Figure 13B A method similar to method 1300A, according to some embodiments, can be generated by S-SN (e.g., Figures 6A to 6D Example method 1300B is implemented in S-SN 104A, the difference being that method 1300A includes box 1309B instead of boxes 709A and 1372.

[0028] Figure 14 A method similar to 1100, according to some embodiments, can be generated by a C-SN (e.g., Figures 6A to 6D Example method 1400 is implemented in C-SN 106A, except that method 1400 includes boxes 1472 and 1474 instead of box 1162.

[0029] Figure 15 Similar methods 1100, 1200, and 1400, according to some embodiments, are shown that can be generated by a C-SN (e.g., Figures 6A to 6D Example method 1500 of the CU implementation of C-SN 106A. Detailed Implementation

[0030] Figure 1AAn example wireless communication system 100 in which communication devices can implement these technologies is depicted. The wireless communication system 100 includes a UE 102, a base station (BS) 104A, a base station 106A, and a core network (CN) 110. The UE 102 is initially connected to base station 104A. In some scenarios, base station 104A can perform SN addition to configure the UE 102 to operate under dual connectivity (DC) with both base station 104A and base station 106A. Base stations 104A and 106A operate as the MN and SN of the UE 102, respectively.

[0031] In various configurations of the wireless communication system 100, base station 104A can be implemented as a primary eNB (MeNB) or primary gNB (MgNB), and base station 106A can be implemented as a secondary gNB (SgNB). UE 102 can communicate with base station 104A and base station 106A via the same RAT (such as EUTRA or NR) or different RATs. When base station 104A is a MeNB and base station 106A is an SgNB, UE 102 can be in EUTRA-NR DC (EN-DC) with both the MeNB and SgNB.

[0032] In some cases, the MeNB or SeNB is implemented as an ng-eNB instead of an eNB. When base station 104A is the primary ng-eNB (Mng-eNB) and base station 106A is the SgNB, UE 102 can be in a next-generation (NG) EUTRA-NR DC (NGEN-DC) with both the Mng-eNB and SgNB. When base station 104A is a MgNB and base station 106A is an SgNB, UE 102 can be in an NR-NR DC (NR-DC) with both the MgNB and SgNB. When base station 104A is a MgNB and base station 106A is a secondary ng-eNB (Sng-eNB), UE 102 can be in an NR-EUTRA DC (NE-DC) with both the MgNB and Sng-eNB.

[0033] In the scenario where UE 102 switches from base station 104A to base station 106A, base stations 104A and 106A operate as the source base station (S-BS) and the target base station (T-BS), respectively. For example, before the handover, UE 102 can operate with base station 104A and the auxiliary base station (T-BS). Figure 1A (Not shown in the diagram) Operation under DC. After the handover is completed, UE 102 can continue to operate under DC with base station 106A and the additional base station or under single connection (SC) with base station 106A. In this case, base stations 104A and 106A operate as the source MN (S-MN) and the target MN (T-MN), respectively.

[0034] The core network (CN) 110 can be either the Evolved Packet Core (EPC) 111 or the 5th Generation Core (5GC) 160; both are... Figure 1A The base station 104A can be an eNB supporting an S1 interface for communication with EPC 111, an ng-eNB supporting an NG interface for communication with 5GC 160, or a gNB supporting an NR radio interface and an NG interface for communication with 5GC 160. To exchange messages directly with each other during the scenarios discussed below, base stations 104A and 106A can support X2 or Xn interfaces. Among other components, EPC 111 may include a Serving Gateway (SGW) 112, a Mobility Management Entity (MME) 114, and a Packet Data Network Gateway (PGW) 116. SGW 112 is generally configured to deliver user plane packets related to audio calls, video calls, Internet traffic, etc., and MME 114 is configured to manage authentication, registration, paging, and other related functions. PGW 116 provides connectivity from the UE to one or more external packet data networks (e.g., Internet networks and / or Internet Protocol (IP) Multimedia Subsystem (IMS) networks). 5GC 160 includes User Plane Functions (UPF) 162, Access and Mobility Management (AMF) 164, and / or Session Management Functions (SMF) 166. UPF 162 is generally configured to deliver user plane packets related to audio calls, video calls, Internet traffic, etc., AMF 164 is configured to manage authentication, registration, paging, and other related functions, and SMF 166 is configured to manage PDU sessions.

[0035] like Figure 1A As shown, base station 104A supports cell 124A, and base station 106A supports cell 126A. Cells 124A and 126A can partially overlap, allowing UE 102 to communicate with the DC of both base stations 104A and 106A, where one base station is MN and the other is SN. Base station 104A can support additional cells (such as cells 124B and 124C), and base station 106A can support additional cells (…). Figure 1A (Not shown in the diagram). Cells 124A, 124B, and 124C may partially overlap, allowing UE 102 to communicate with base station 104A via carrier aggregation (CA). Base station 104A may operate cells 124A, 124B, and 124C via one or more transmit and receive points (TRPs). More specifically, when UE 102 is in DC with base stations 104A and 106A, one of base stations 104A and 106A operates as a MeNB, Mng-eNB, or MgNB, while the other base station operates as an SgNB or Sng-eNB.

[0036] Generally, the wireless communication network 100 may include any suitable number of base stations supporting NR cells and / or EUTRA cells. More specifically, the EPC 111 or 5GC 160 may connect to any suitable number of base stations supporting NR cells and / or EUTRA cells. See below for reference. Figure 1B An example configuration of CN 110 connected to an additional base station is discussed. Although the examples below specifically refer to particular CN types (EPC, 5GC) and RAT types (5G NR and EUTRA), in general, the techniques disclosed herein can also be applied to other suitable radio access and / or core network technologies, such as sixth-generation (6G) radio access and / or 6G core network or 5G NR-6G DC.

[0037] Continue to refer to Figure 1A Base station 104A is equipped with processing hardware 130, which may include one or more general-purpose processors (e.g., CPUs) and non-transitory computer-readable storage of instructions executed by the one or more general-purpose processors. Additionally or alternatively, processing hardware 130 may include dedicated processing units. Processing hardware 130 may include a PHY controller 132 configured to transmit data and control signals on a physical downlink (DL) channel and DL reference signals with one or more user equipments (e.g., UE 102) via one or more cells (e.g., cells 124A, 124B, and / or 124C) and / or one or more TRPs. PHY controller 132 is also configured to receive data and control signals on a physical uplink (UL) channel and / or UL reference signals with one or more user equipments via one or more cells (e.g., cells 124A, 124B, and / or 124C) and / or one or more TRPs. In an example implementation, processing hardware 130 includes a MAC controller 134 configured to perform MAC functions with one or more user equipments. MAC functions include random access (RA) procedures, managing UL timing advance (TA) for one or more user equipment (UEs), and / or communicating UL / DL MAC PDUs with one or more UEs. MAC functions include Lower Triggered Mobility (LTM) related functions as described below. Processing hardware 130 may further include an RRC controller 136 to implement procedures and messaging at the RRC sublayer of the protocol communication stack. For example, RRC controller 132 may be configured to support RRC messaging associated with handover procedures and / or support necessary operations when base station 104A operates as MN relative to SN or as SN relative to MN. Base station 106A may include processing hardware 140 similar to processing hardware 130. Specifically, components 142, 144, and 146 may be similar to components 132, 134, and 136, respectively.

[0038] 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 executable on the one or more general-purpose processors, and / or dedicated processing units. PHY controller 152 is also configured to receive data and control signals with base station 104A or 106A via one or more cells (e.g., cells 124A, 124B, 124C, and / or 126A) and / or one or more TRPs on physical DL channels and / or DL ​​reference signals. PHY controller 152 is also configured to transmit data and control signals with base station 104A or 106A via one or more cells (e.g., cells 124A, 124B, 124C, and / or 126A) and / or one or more TRPs on physical UL channels and / or UL reference signals. In an example implementation, processing hardware 150 includes MAC controller 154, which is configured to perform MAC functions with base station 104A or 106A. For example, MAC functions include random access procedures, managing UL timing advances for one or more user facilities, and transmitting UL / DL MAC PDUs with base station 104A or 106A. In another example, MAC functions include LTM-related functions as described below. Processing hardware 150 may further include RRC controller 156 to implement procedures and message passing at the RRC sublayer of the protocol communication stack.

[0039] In operation, UE 102 can use radio bearers (e.g., DRB or SRB) that terminate at MN 104A or SN 106A at different times under DC. When communicating on radio bearers in the uplink (UL) (from UE 102 to the base station) and / or downlink (from the base station to UE 102) directions, UE 102 can apply one or more security keys.

[0040] Figure 1CAn example distributed implementation of a base station, such as base station 104A or 106A, is depicted. In this implementation, the base station may include a centralized unit (CU) 172 and one or more distributed units (DUs) 174. CU 172 is equipped with processing hardware that may include one or more general-purpose processors (such as CPUs) and non-transitory computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors, and / or dedicated processing units. In one example, CU 172 is equipped with processing hardware 130. In another example, CU 172 is equipped with processing hardware 140. Processing hardware 140 in the example implementation includes an SN RRC controller 142 configured to manage or control one or more RRC configurations and / or RRC procedures when base station 106A operates as an SN. DU 174A is also equipped with processing hardware that may include one or more general-purpose processors (such as CPUs) and non-transitory computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors, and / or dedicated processing units. In some examples, the processing hardware in the example implementation includes a Media Access Control (MAC) controller configured to manage or control one or more MAC operations or procedures (e.g., random access procedures) and a Radio Link Control (RLC) controller configured to manage or control one or more RLC operations or procedures when the base station 106A operates as an MN or SN. The processing hardware may further include a physical layer controller configured to manage or control one or more physical layer operations or procedures.

[0041] Figure 2A An example protocol stack 200 is shown in a simplified manner, which UE 102 can use to communicate with eNB / ng-eNB or gNB (e.g., one or more of base stations 104A and 106A).

[0042] In example stack 200, the EUTRA physical layer (PHY) 202A provides a transport channel to the EUTRA MAC sublayer 204A, which in turn provides a logical channel to the EUTRA RLC sublayer 206A. The EUTRA RLC sublayer 206A then provides an RLC channel to the EUTRA PDCP sublayer 208 and, in some cases, to the NR PDCP sublayer 210. Similarly, the NRPHY 202B provides a transport channel to the NR MAC sublayer 204B, which in turn provides a logical channel to the NR RLC sublayer 206B. The NR RLC sublayer 206B then provides data delivery services to the NR PDCP sublayer 210. The NR PDCP sublayer 210 can then provide data delivery services to the Serving Data Adaptation Protocol (SDAP) 212 or the Radio Resource Control (RRC) sublayer. Figure 2A (Not shown in the image) provides data transfer services. In some implementations, UE 102 supports both EUTRA and NR stacks, such as... Figure 2A As shown, this supports handover between EUTRA and NR base stations and / or supports DCs via EUTRA and NR interfaces. Further, as... Figure 2A As shown, UE102 can support the layering of NR PDCP 210 on EUTRA RLC 206A, and the layering of SDAP sublayer 212 on NR PDCP sublayer 210.

[0043] EUTRA PDCP sublayer 208 and NR PDCP sublayer 210 (e.g., from an Internet Protocol (IP) layer layered directly or indirectly on PDCP layers 208 or 210) receive packets that can be referred to as Service Data Units (SDUs), and (e.g., to RLC layers 206A or 206B) output packets that can be referred to as Protocol Data Units (PDUs). For simplicity, except where the difference between SDU and PDU is relevant, this disclosure refers to both SDU and PDU as "packets".

[0044] On the control plane, EUTRA PDCP sublayer 208 and NR PDCP sublayer 210 can provide signaling radio bearer (SRB) or RRC sublayer ( Figure 2A (Not shown) to exchange, for example, RRC messages or Non-Access Stratum (NAS) messages. On the user plane, EUTRA PDCP sublayer 208 and NR PDCP sublayer 210 can provide data radio bearers (DRBs) to support data exchange. The data exchanged on NR PDCP sublayer 210 can be SDAP PDUs, Internet Protocol (IP) packets, or Ethernet packets.

[0045] Figure 2BAn example protocol stack 250 is shown in a simplified manner, illustrating how UE 102 can communicate with DU (e.g., DU 174) and CU (e.g., CU 172). The radio protocol stack 200 is functionally decomposed, as shown by... Figure 2B The radio protocol stack 250 is shown in the diagram. At either base station 104A or 106A, the CU can retain all control and upper-layer functionality (e.g., RRC214, SDAP 212, NR PDCP 210), while lower-layer operations (e.g., NR RLC 206B, NR MAC 204B, and NR PHY202B) are delegated to the DU. To support connectivity to the 5GC, NR PDCP 210 provides SRBs to RRC 214, and NR PDCP 210 provides DRBs to SDAP 212 and SRBs to RRC 214.

[0046] Next is one of them Figure 1A This describes several example scenarios in which the base station operating in the system sends a configuration to the UE 102 and later activates the configuration for communication between the UE 102 and the base station. Generally, Figures 3 to 5 Similar events in the figure are labeled with similar reference numerals (e.g., event 302 is similar to...). Figure 4 Event 402 and Figure 5 Event 502 and Event 390 are similar. Figure 4 Event 490 and Figure 5 Event 590), the differences of which will be discussed where appropriate below. Apart from the differences shown in the figures and discussed below, any alternative implementations of the alternative implementations discussed for a particular event (e.g., for messaging and processing) may be applied to other events labeled with similar reference numerals in the figures.

[0047] First refer to Figure 3 In scenario 300, base station 104A includes CU 172 and DU 174, and DU 174 operates in cell 124A. UE 102 initially uses a serving DU configuration to communicate with DU 174 on the serving cell (e.g., cell 124A), and uses a serving CU configuration to communicate with CU 172 via DU 174 302. DU 174 is the serving DU or source DU (S-DU) for UE 102. In other words, DU 174 is the serving DU (S-DU) that is communicating with UE 102. In some implementations, UE 102 uses a serving DU configuration in cell 124A and other cells (e.g., Figure 1AUE 102 communicates with DU 174 via carrier aggregation (CA) on cell 124A (not shown). DU 174 operates other cells. Cell 124A and / or other cells are the serving cells of UE 102. In other implementations, UE 102 communicates with DU 174 only on cell 124A. In some implementations, UE 102 communicates with DU 174 on cell 124A and / or other cells (i.e., serving cells) via one or more TRPs. In the following description, events 394, 324, 350, 352, 354, and 326 occur on the serving cell. In some implementations, cell 124A may be a PCell. In such a case, the other cells include SCells and / or additional cells associated with a PCell or SCell. In other implementations, cell 124A may be an SCell, and one of the other cells is a PCell. In such a case, the remaining cells include SCells and / or additional cells associated with a PCell or SCell. In the following description, base station 104A may be DU 174, CU 172, or DU 174 and CU 172.

[0048] In event 302, UE 102 may transmit UL PDUs and / or UL control signals to base station 104A via one or more TRPs in cell 124A and / or other cells. In some implementations, UE 102 communicates UL PDUs and / or DL ​​PDUs with base station 104A via a radio bearer, which may include SRBs and / or DRBs. Base station 104A may configure the radio bearer for UE 102. In some implementations, UL control signals include UL control information, channel state information, Hybrid Automatic Repeat Request (HARQ) acknowledgment (ACK), HARQ negation ACK, scheduling request, and / or probe reference signals. Similarly, UE 102 may receive DL PDUs and / or DL ​​control signals from base station 104A via one or more TRPs in cell 124A and / or other cells. In some implementations, DL control signals include downlink control information (DCI) and reference signals (e.g., synchronization signal blocks, channel state information reference signals (CSI-RS), and / or tracking reference signals). Base station 104A can transmit DCI on the physical downlink control channel (PDCCH) monitored by UE 102 in cell 124A and / or other cells via one or more TRPs.

[0049] In some implementations, the serving DU configuration includes physical layer configuration parameters, MAC configuration parameters, and / or RLC configuration parameters. In some implementations, the serving DU configuration includes at least one first non-LTM TCI state configuration for the serving cell. In some implementations, DU 174 may send these configuration parameters and / or the first non-LTM TCI state configuration to CU 172. CU 172 generates one or more messages (e.g., RRC reconfiguration messages) including these configuration parameters and / or the first non-LTM TCI state configuration and sends these messages to UE 102 via DU 174. In other implementations, DU 174 sends the configuration parameters and / or the first non-LTM TCI state configuration directly to UE 102. In some implementations, the serving DU configuration is as defined in 3GPP specification 38.331. CellGroupConfig IE. In other implementations, the service DU configuration includes... CellGroupConfig Configuration parameters in IE. In some implementations, the Serving CU configuration includes PDCP configuration parameters, measurement configuration parameters, and / or radio bearer configuration parameters. In some implementations, the Serving CU configuration includes those defined in 3GPP specification 38.331. MeasConfig IE and / or RadioBearerConfig IE, or including MeasConfig IE and / or RadioBearerConfig Configuration parameters in IE. Radio configuration parameters or RadioBearerConfig IE configures one or more DRBs. In some implementations, the service DU configuration includes... CSI- MeasConfig IE or configuration parameters used for Channel State Information (CSI) measurement and reporting. In other implementations, the service CU configuration includes... CSI-MeasConfig IE or configuration parameters used for CSI measurement and reporting. In some implementations, UE 102 receives the service CU configuration or configuration parameters in the service CU configuration from CU 172 via DU 174. In other implementations, UE 102 receives a portion of the service CU configuration and / or a portion of the service DU configuration from a base station other than base station 104A, and receives the remainder of these configuration parameters from base station 104A.

[0050] In some implementations, DU 174 and UE 102 communicate with each other using a first non-LTM TCI state configuration, for example, in events 302, 318, 320, 324, 350, 354, and / or 326. In some implementations, DU 174 sends at least one first non-LTM TCI state activation / deactivation command (e.g., MAC control element (CE)) to UE 102 to activate the first non-LTM TCI state configuration. UE 102 activates the first non-LTM TCI state configuration in response to the first non-LTM TCI state activation / deactivation command. In some implementations, DU 174 includes a serving cell ID (e.g., serving cell index) in each of the first non-LTM TCI state activation / deactivation commands to identify the first non-LTM TCI state configuration. Each serving cell ID indicates a corresponding serving cell among serving cells. In some implementations, the serving DU configuration includes serving cell IDs and configures the association between the serving cell IDs and the first non-LTM TCI state configuration.

[0051] When communicating with base station 104A, UE 102 sends at least one measurement report (304) to DU 174. In some implementations, the measurement report includes measurement results for the serving cell (e.g., cell 124A) and / or at least one non-serving cell for UE 102. For each of the measurement reports, DU 174 sends a DU-to-CU message (306) including the measurement report to CU 172. In some implementations, the DU-to-CU message of event 306 is an F1 Application Protocol (F1AP) message (e.g., UL RRC News transfer (Message). At least one serving cell includes cell 124A and / or other cells, and at least one non-serving cell includes cell 124B and / or additional cells. In some implementations, the serving CU configuration includes at least one measurement configuration. Based on the measurement configuration, UE 102 performs measurements and sends a 304 measurement report to DU 174. In some implementations, the measurement configuration includes a Layer 3 (L3) measurement configuration (e.g., MeasConfig (IE), and the measurement report includes the L3 measurement report.

[0052] Upon receiving one or more measurement reports from UE 102 (e.g., in response to receiving one or more measurement reports from UE 102), CU 172 determines to prepare a first cell (e.g., cell 1, such as cell 124B) as an LTM candidate cell for UE 102. In some implementations, base station 104A determines to prepare the first cell for UE 102 because the measurement reports indicate that the first cell can be used by base station 104A to communicate with UE 102. In some implementations, base station 104A determines to prepare the first cell for UE 102 because the measurement reports indicate that the first cell is eligible to be an LTM candidate cell that can be used for communication with UE 102. In some implementations, CU 172 determines to prepare the first cell for UE 102 if the L3 measurement reports indicate that the signal strength and / or quality of the first cell is higher than a first predetermined threshold, better than the strength and / or quality of the serving cell (e.g., cell 124A), and / or better than the strength and / or quality of the serving cell by a first predetermined threshold. Alternatively, CU 172 determines the first cell to be used for UE 102, regardless of whether a measurement report is received from UE 102.

[0053] In response to determining that a first cell is ready for LTM, CU 172 sends a 308 First CU to DU message to DU 174 to prepare the first cell for UE 102. In some implementations, CU 172 includes the cell identifier (ID) 1 of the first cell in the First CU to DU message to request DU 174 to prepare the first cell for LTM for UE 102. For example, cell ID 1 is the Cell Global Identifier (CGI). In another example, the cell ID is part of the CGI. In yet another example, the cell ID is the Physical Cell ID (PCI). In some implementations, CU 172 includes an LTM indicator in the First CU to DU message to indicate to DU 174 that the first cell is ready for LTM. In some implementations, CU 172 includes the LTM indicator in... LTM Information Establishment In IE, and will LTM Information Establishment The IE is included in the first CU to DU message. In other implementations, CU 172 includes the LTM indicator. LTM Information Modification In IE, and will LTM information modification IE Included in the first CU to DU message.

[0054] In response to the first CU to DU message, DU 174 generates a first LTM DU configuration (hereinafter referred to as LTM DU configuration 1) for UE 102, which configures a first cell for LTM. In some implementations, CU 172 includes a first LTM configuration ID (i.e., hereinafter referred to as LTM ID 1) in the first CU to DU message, and DU 174 associates LTM ID 1 and / or cell ID 1 with LTM DU configuration 1. Then, DU 174 sends a first DU to CU message including LTM DU configuration 1 to CU 172 in response to the first CU to DU message.

[0055] Events 308 and 310 Figure 3 This process is collectively referred to as the LTM preparation process 390.

[0056] In some implementations, DU 174 includes the cell ID 1 of the first cell associated with LTM DU configuration 1 in the first DU to CU message to indicate that LTM DU configuration 1 is configured for or associated with the first cell. When CU 172 and DU 174 perform multiple LTM preparation procedures (e.g., procedures 390 and LTM preparation procedures 2, ..., N described below) to prepare multiple LTM candidate cells, CU 172 can determine whether LTM DU configuration 1 is configured for or associated with the first cell based on the cell ID 1 in the first DU to CU message.

[0057] In some implementations, CU 172 does not include the LTM reference DU configuration in the first CU to DU message. In such cases, DU 174 generates the LTM reference DU configuration and includes it in the first DU to CU message. In some implementations, DU 174 generates LTM DU configuration 1 as an incremental configuration to expand the LTM reference DU configuration. In other implementations, DU 174 generates LTM DU configuration 1 as a complete configuration, i.e., not based on the LTM reference DU configuration.

[0058] In some implementations, CU 172 includes the LTM reference DU configuration request in the first CU-DU message, and DU 174 generates the LTM reference DU configuration in response to the request and includes it in the first DU-CU message. In some implementations, CU 172 determines whether UE 102 supports the LTM reference configuration. If CU 172 determines that UE 102 supports the LTM reference configuration, then CU 172 includes the LTM reference DU configuration request in the first CU-DU message. DU 174 includes the LTM reference DU configuration in response to the LTM reference DU configuration request in the first DU-CU message. Otherwise, if CU 172 determines that UE 102 does not support the LTM reference configuration, then CU 172 does not include the LTM reference DU configuration request in the first CU-DU message. In this case, DU 174 can generate LTM DU configuration 1 as a complete configuration and may not include the LTM reference DU configuration in the first DU-CU message. In other implementations, CU 172 sends an additional CU-DU message to DU 174, including an LTM reference DU configuration request, instead of the first CU-DU message. In response, DU 174 sends an additional DU-CU message to CU 172, including the LTM reference DU configuration. In yet another implementation, DU 174 determines whether UE 102 supports the LTM reference configuration. If DU 174 determines that UE 102 supports the LTM reference configuration, then DU 174 includes the LTM reference DU configuration in the first DU-CU message. Otherwise, if DU 174 determines that UE 102 does not support the LTM reference configuration, then DU 174 does not include the LTM reference DU configuration in the first DU-CU message.

[0059] In some implementations, CU 172 includes the LTM reference DU configuration in the first CU to DU message. In some implementations, CU 172, as described above and specifically... Figure 4 During the LTM preparation process, an LTM reference DU configuration is received from the additional DU. In other implementations, CU 172 is pre-configured with an LTM reference DU configuration. In some implementations, DU 174 generates LTM DU configuration 1 as an incremental configuration to expand the LTM reference DU configuration. In other implementations, DU 174 ignores the LTM reference DU configuration and generates LTM DU configuration 1 as a complete configuration, i.e., not based on the LTM reference DU configuration.

[0060] If DU 174 generates LTM DU configuration 1 as a complete configuration, DU 174 can include a complete configuration indication in the first DU to CU message to indicate that LTM DU configuration 1 is a complete configuration. In some implementations, if the first CU to DU message does not include the LTM reference DU configuration, then CU 172 can determine that LTM DU configuration 1 is a complete configuration. Otherwise, if the first CU to DU message includes the LTM reference DU configuration, then CU 172 can determine that LTM DU configuration 1 is an incremental configuration.

[0061] In some implementations, the LTM reference DU configuration differs from the service DU configuration. In some implementations, portions of the LTM reference DU configuration are identical to portions of the service DU configuration, but the remainder of the LTM reference DU configuration differs from the remainder of the service DU configuration. In other implementations, the LTM reference DU configuration is identical to the service DU configuration. In some implementations, the LTM reference DU configuration includes physical layer configuration parameters, MAC configuration parameters, and / or RLC configuration parameters. In some implementations, the LTM reference DU configuration is as defined in 3GPP specification 38.331. CellGroupConfig IE. In other implementations, the LTM reference DU configuration includes... CellGroupConfig Configuration parameters in IE. In some implementations, the LTM reference DU configuration includes... CSI-MeasConfig IE or configuration parameters used for Channel State Information (CSI) measurement and / or reporting.

[0062] In some implementations, the LTM reference DU configuration differs from the service DU configuration. In some implementations, portions of the LTM reference DU configuration are identical to portions of the service DU configuration, but the remainder of the LTM reference DU configuration differs from the remainder of the service DU configuration. In other implementations, the LTM reference DU configuration is identical to the service DU configuration.

[0063] To prepare the first cell as an LTM candidate cell for UE 102, CU 172 may send a second CU-DU message (312) to DU 174. This second CU-DU message includes CSI resource configuration (e.g., CSI resource configuration 1) and / or LTM SSB configuration (i.e., LTM SSB configuration 1) to request DU 174 to generate one or more CSI report configurations (e.g., (LTM) CSI report configuration 1). The CSI resource configuration (e.g., (LTM) CSI resource configuration 1) includes configuration parameters for at least one reference signal (RS) transmitted on the first cell. The RS includes an SSB and / or a CSI-RS. The LTM SSB configuration includes SSB configuration parameters that configure the SSB frequency, subcarrier spacing, SSB periodicity, SSB location, and / or SSB power of the SSB transmitted on the first cell.

[0064] Upon receiving the CSI resource configuration (e.g., in response to the reception), DU 174 generates one or more CSI report configurations based on the CSI resource configuration and includes the CSI report configuration in the service DU configuration (referred to as the second service DU configuration in event 302 to distinguish it from the service DU configuration). In some implementations, the CSI report configuration configures UE 102 to send CSI reports based on RS measurements. DU 174 sends a second DU to CU message 314, including the second service DU configuration, to CU 172. In some implementations, the CSI resource configuration includes (e.g., is or includes) one or more... LTM-CSI- ResourceConfig-r18 IE. In other implementations, CSI resource configuration includes... ltm-CSI- ResourceConfigToAddModList Field / IE. In some implementations, the second service DU configuration is... CellGroupConfig IE.

[0065] In some implementations, CU 172 includes Cell ID 1 and / or LTM ID 1 in the second CU-DU message. In one implementation, CU 172 does this to indicate that the CSI resource configuration is associated with the first cell. In another implementation, CU 172 does this for DU 174 to associate LTM ID 1 with the first cell, Cell ID 1, LTM DU configuration 1, and / or CSI reporting configuration. Based on the above implementations, DU 174 can associate LTM ID 1 and / or Cell ID 1 with configurations associated with the first cell (e.g., LTM DU configuration 1, CSI resource configuration, and / or CSI reporting configuration). In such implementations, CU 172 may or may not include LTM ID 1 in the first CU-DU message.

[0066] In some alternative implementations, CU 172 includes CSI resource configuration in the first CU to DU message, and DU 174 includes CSI report configuration in the first DU to CU message.

[0067] In some implementations, DU 174 sends LTM SSB configuration or SSB configuration parameters to CU 172, for example, in a first DU to CU message, a second DU to CU message, or an additional DU to CU message. In some implementations, DU 174 sends an additional DU to CU message in response to receiving an additional CU to DU message from CU 172. In other implementations, DU 174 sends a fourth DU to CU message in response to receiving a first CU to DU message or a second CU to DU message (e.g., ...). UE context modification requirements information).

[0068] Events 312 and 314 Figure 3 This is collectively referred to as the LTM CSI report configuration and / or LTM ID configuration process 392.

[0069] After receiving the first DU to CU message, CU 172 generates a first LTM candidate configuration (i.e., LTM candidate configuration 1) including LTM DU configuration 1, and generates a first RRC reconfiguration message including LTM candidate configuration 1 and LTM ID 1. In some implementations, CU 172 includes LTM CU configuration 1 in LTM candidate configuration 1. In other implementations, CU 172 does not include LTM CU configuration in LTM candidate configuration 1. CU 172 sends a third CU to DU message 316, including the first RRC reconfiguration message, to DU 174. Subsequently, DU 174 sends a first RRC reconfiguration message 318 to UE 102. In response, UE 102 sends a first RRC reconfiguration complete message 320 to DU 174. Then, DU 174 sends a third DU to CU message 322, including the first RRC reconfiguration complete message, to CU 172.

[0070] If the first DU to CU message includes an LTM reference DU configuration, then CU 172 generates an LTM reference configuration that includes the LTM reference DU configuration. In this case, CU 172 can include the LTM reference configuration in the first RRC reconfiguration message. In some implementations, CU 172 includes the LTM reference CU configuration in the LTM reference configuration. In this case, CU 172 can generate LTM CU configuration 1 as an incremental configuration based on the LTM reference CU configuration. In other implementations, CU 172 does not include the LTM reference CU configuration in the LTM reference configuration. In this case, CU 172 can generate LTM CU configuration 1 as a complete configuration. Alternatively, similar to events 316 and 318, CU 172 sends a second RRC reconfiguration message including the LTM reference configuration to UE 102 via DU 174. In response, similar to events 320 and 322, UE 102 sends a second RRC reconfiguration complete message to CU 172 via DU 174. In some implementations, if CU 172 does not receive the LTM reference DU configuration, CU 172 can generate an LTM reference configuration that includes only the LTM reference CU configuration. In other implementations, if CU 172 does not receive the LTM reference DU configuration, CU 172 may not generate an LTM reference configuration.

[0071] In some implementations, if the first DU to CU message includes a complete configuration indication, then CU 172 can determine that LTM DU configuration 1 is a complete configuration. Otherwise, if the first DU to CU message does not include a complete configuration indication, then CU 172 can determine that LTM DU configuration 1 is an incremental configuration. In some implementations, if LTM DU configuration 1 is a complete configuration, then CU 172 generates LTM candidate configuration 1 as a complete configuration. Otherwise, if LTM DU configuration 1 is an incremental configuration, then CU 172 generates LTM candidate configuration 1 as an incremental configuration. If LTM candidate configuration 1 is a complete configuration, then CU 172 includes a complete configuration indication in the first RRC reconfiguration message to indicate that LTM candidate configuration 1 is a complete configuration. If LTM candidate configuration 1 is an incremental configuration, then CU 172 excludes the complete configuration indication from the first RRC reconfiguration message to indicate that LTM candidate configuration 1 is an incremental configuration.

[0072] In the case of CU 172 performing procedure 392, CU 172 may include the second service DU configuration in the first RRC reconfiguration message. Alternatively, similar to events 316 and 318, CU 172 sends a third RRC reconfiguration message including the second service DU configuration to UE 102 via DU 174. In response, similar to events 320 and 322, UE 102 sends a third RRC reconfiguration complete message to CU 172 via DU 174.

[0073] In some implementations, CU 172 includes CSI resource configuration in the first, second, or third RRC reconfiguration message. In other implementations, similar to events 316 and 318, CU 172 sends a fourth RRC reconfiguration message including CSI resource configuration to UE 102 via DU 174. In response, similar to events 320 and 322, UE 102 sends a fourth RRC reconfiguration complete message to UE 102 via DU 174.

[0074] In some implementations, DU 174 sends a DU-to-CU message to CU 172, including early synchronization information for UE 102. The DU-to-CU message can be a first DU-to-CU message, a second DU-to-CU message, or a fourth DU-to-CU message. In some implementations, DU 174 sends a fourth DU-to-CU message in response to receiving a fourth CU-to-DU message from CU 172. In other implementations, DU 174 sends a fourth DU-to-CU message in response to receiving a first CU-to-DU message or a second CU-to-DU message (e.g., ...). UE context modification requirementsIn one implementation, if DU 174 determines that UE 102 supports (i.e., is capable of) early UL synchronization with the LTM candidate cell (e.g., early TA acquisition with the LTM candidate cell, early RA on the LTM candidate cell, or TA measured by the UE), then DU 174 sends a fourth DU to CU message. Otherwise, if DU 174 determines that UE 102 does not support early UL synchronization with the LTM candidate cell, then DU 174 does not send early synchronization information to CU 172. In other implementations, CU 172 sends a CU to DU message that includes an early synchronization information request (e.g., IE), and DU 174 includes the early synchronization information in the DU to CU message in response to the early synchronization information request. The CU to DU message can be a first CU to DU message, a second CU to DU message, or a fourth CU to DU message. In one implementation, if CU 172 determines that UE 102 supports early UL synchronization with the LTM candidate cell, then CU 172 sends a CU to DU message. Otherwise, if CU 172 determines that UE 102 does not support early UL synchronization with the LTM candidate cell, CU 172 does not request DU 174 to provide early synchronization information for UE 102. If CU 172 receives early synchronization information, CU 172 includes the early synchronization information in a first RRC reconfiguration message, a second RRC reconfiguration message, a third RRC reconfiguration message, or a fourth RRC reconfiguration message. Alternatively, similar to events 316 and 318, CU 172 sends a fifth RRC reconfiguration message including the early synchronization information to UE 102 via DU 174. In response, similar to events 320 and 322, UE 102 sends a fifth RRC reconfiguration complete message to CU 172 via DU 174.

[0075] In some implementations, the early synchronization information includes a Random Access Channel (RACH) configuration (i.e., RACH configuration 1) and / or one or more TCI state configurations (i.e., TCI state configuration 1). In some implementations, the early synchronization request may include a request for RACH configuration. If the early synchronization request includes a request for RACH configuration, then DU 174 includes the RACH configuration in the early synchronization information or in a DU-to-CU message (e.g., a first DU-to-CU message, a second DU-to-CU message, or a fourth DU-to-CU message). Otherwise, if the early synchronization request does not include a request for RACH configuration, then DU 174 does not include the RACH configuration in the early synchronization information or in a DU-to-CU message.

[0076] In some implementations, CU 172 includes one or more other LTM-related configurations for the first cell in the first RRC reconfiguration message, the second RRC reconfiguration message, the third RRC reconfiguration message, the fourth RRC reconfiguration message, and / or the fifth RRC reconfiguration message. For example, other LTM-related configurations include the PCI and / or LTM SSB configurations for the first cell.

[0077] Events 316, 318, 320, and 322 are in Figure 3 This is collectively referred to as LTM configuration delivery process 394. The second RRC reconfiguration message, the third RRC reconfiguration message, the fourth RRC reconfiguration message, and / or the fifth RRC reconfiguration message, as well as the second RRC reconfiguration completion message, the third RRC reconfiguration completion message, the fourth RRC reconfiguration completion message, and / or the fifth RRC reconfiguration completion message, the related CU to DU messages, and / or the related DU to CU messages are also considered part of LTM configuration delivery process 394. In some implementations, the aforementioned RRC reconfiguration messages and RRC reconfiguration completion messages are respectively... RRCReconfiguration Messages and RRCReconfigurationComplete information.

[0078] In some implementations, the first CU to DU message is UE Context Modification Request The message, and the first DU to CU message is UE context modification response Message. In some implementations, the second CU to DU message is UE Context Modification Request The message, and the second DU to CU message is UE Context Modification Response Message or UE context modification requirements Message. In UE top and bottom Document revision requirements In the case of a message, CU 172 can respond to UE context modification requirements Message sent to DU 174 UE The following text has been revised and confirmed. Message. In some implementations, the third CU to DU message is DL RRC Message Passing Message. In other implementations, the third CU to DU message is UE Context Modification Request Message. In some implementations, the third DU to CU message is UL RRC Messaging Message. In other implementations, the third DU to CU message is UE context modification response information.

[0079] In some implementations, the LTM reference CU configuration differs from the service CU configuration. In some implementations, portions of the LTM reference CU configuration are identical to portions of the service CU configuration, while the remainder of the LTM reference CU configuration differs from the remainder of the service CU configuration. In other implementations, the LTM reference CU configuration is identical to the service CU configuration.

[0080] In some implementations, the LTM reference CU configuration includes PDCP configuration parameters, measurement configuration parameters, and / or radio bearer configuration parameters. In some implementations, LTM CU configuration 1 includes those defined in 3GPP specification 38.331. MeasConfig IE and / or RadioBearerConfig IE, or including MeasConfig IE and / or RadioBearerConfig Configuration parameters in Internet Explorer.

[0081] In some implementations, LTM CU Configuration 1 and / or LTM Reference CU Configuration include PDCP configuration parameters, measurement configuration parameters, and / or radio bearer configuration parameters. In some implementations, LTM CU Configuration 1 or LTM Reference CU Configuration includes those defined in 3GPP specification 38.331. MeasConfig IE and / or RadioBearerConfig IE, or including MeasConfig IE and / or RadioBearerConfig Configuration parameters in Internet Explorer.

[0082] In some implementations, LTM DU configuration 1 includes multiple configuration parameters for UE 102 to communicate with DU 174 on the first cell. In some implementations, these multiple configuration parameters include physical layer configuration parameters (e.g., PhysicalCellGroupConfig IE), MAC layer configuration parameters (e.g., MAC-CellGroupConfig IE) and / or RLC configuration parameters (e.g., RLC-BearerConfig IE). In some further implementations, these multiple configuration parameters include special cell configurations (e.g., SpCellConfig IE) and / or one or more SCell configurations (e.g., SCellConfig (IE). In some implementations, LTM DU configuration 1 is defined in 3GPP specification 38.331. CellGroupConfig IE. In other implementations, LTM DU configuration 1 includes... CellGroupConfig Configuration parameters in Internet Explorer.

[0083] In some implementations, LTM DU configuration 1 includes a first L1 measurement configuration (e.g., CSI-MeasConfigThe first L1 measurement configuration includes at least one first RS resource configuration and / or at least one first reporting configuration. In other implementations, LTM CU configuration 1 includes a first TCI status configuration. In some implementations, the first L1 measurement configuration includes at least one first RS resource configuration and / or at least one first reporting configuration. In some implementations, the first RS resource configuration configures one or more RSs or one or more RS resources associated with cell 1. RSs include SSBs and / or CSI-RSs. RS resources include SSB resources and / or CSI-RS resources. In some implementations, each RS resource configuration in the first RS resource configuration includes an RS resource configuration ID. In some implementations, the first RS resource configuration is (similar to) CSI-ResourceConfig IE. In some implementations, the first report configuration configures UE 102 to configure one or more UL resources (e.g., PUCCH resources or PUSCH resources) on the first cell to send measurement results (e.g., CSI reports or LTM CSI reports). In some implementations, each first report configuration in the first report configuration includes one or more RS resource configuration IDs identifying one or more RS resource configurations included in the first RS resource configuration. In some implementations, each first TCI state configuration in the first TCI state configuration associates one or two DL RSs with the TCI state associated with the corresponding Quasi-Cooperative Positioning (QCL) type. The DL RS is associated with cell 1.

[0084] After receiving the LTM-related configuration and the second service DU configuration, or after receiving the aforementioned RRC reconfiguration message, UE 102 performs measurements on at least one first RS, generates at least one first L1 measurement result based on the measurements, and sends at least one first L1 measurement report including the first L1 measurement result to DU 174. The first RS may include an SSB and / or a CSI-RS. In some implementations, the first RS and / or the transmission mode of the first RS are configured in the CSI report configuration, LTM SSB configuration, and / or CSI resource configuration. UE 102 performs measurements on the first RS according to the CSI report configuration, LTM SSB configuration, and / or CSI resource configuration.

[0085] After receiving the LTM-related configuration and the second service DU configuration, or after receiving the aforementioned RRC reconfiguration message, UE 102 performs measurements on at least one second RS, generates at least one second L1 measurement result based on the measurements, and sends at least one second L1 measurement report including the first L1 measurement result to DU 174. The second RS may include an SSB and / or a CSI-RS. In some implementations, the second RS and / or the transmission mode of the second RS are configured in one or more second CSI report configurations and / or one or more second CSI resource configurations included in the service DU configuration 302 and / or the second service DU configuration. UE 102 measures the second RS according to the second CSI report configuration and / or the second CSI resource configuration. The second CSI report configuration may include a non-LTM CSI report configuration and / or an LTM CSI report configuration. The second CSI resource configuration may include a non-LTM CSI resource configuration and / or an LTM CSI resource configuration.

[0086] After sending the RACH configuration to UE 102 via CU 172, DU 174 can send a 350 PDCCH command to UE 102 to instruct UE 102 to send an RA preamble on the first cell. In response to the PDCCH command, UE 102 sends the RA preamble on the first cell. DU 174 includes PDCCH command information in the PDCCH command. The PDCCH command information includes an RA preamble index, a UL or supplementary UL indicator, an SSB index, and / or a physical RACH mask index. In some implementations, DU 174 includes LTM ID 1 in the PDCCH command to indicate the first cell. UE 102 identifies the first cell based on LTM ID 1 in the PDCCH command and sends a 352 RA preamble to DU 174 on the first cell using the PDCCH command information. Correspondingly, DU 174 receives the 352 RA preamble according to the PDCCH command information. In some implementations, DU 174 may determine the SSB index based on L1 measurement report 324 and / or CSI resource configuration, CSI report configuration, and / or LTM SSB configuration. In some implementations, the L1 measurement report may include the SSB index. In other implementations, the L1 measurement report includes the SS / PBCH block resource indicator (SSBRI) corresponding to the SSB index. Therefore, DU 174 determines the SSB index based on the SSBRI.

[0087] In some implementations, DU 174 determines whether to send a PDCCH command based on L1 measurement result 324. In some implementations, if the L1 measurement result indicates that the first cell is eligible for UE 102 to perform RA for early UL synchronization, DU 174 sends a PDCCH command. Otherwise, if the L1 measurement result indicates that the first cell is not eligible for UE 102 to perform RA for early UL synchronization, DU 174 avoids sending a PDCCH command. In other implementations, if the L1 measurement result indicates that the first cell is eligible for UE 102 to access, DU 174 sends a PDCCH command. Otherwise, if the L1 measurement result indicates that the first cell is not eligible for UE 102 to access, DU 174 avoids sending a PDCCH command. In yet another implementation, DU 174 sends a PDCCH command after receiving the 320 RRC reconfiguration complete message, regardless of the L1 measurement result 324.

[0088] After sending a 324 L1 measurement report or a 352 RA preamble, UE 102 can send a 354 additional L1 measurement report to DU 174, similar to event 324. Based on the additional L1 measurement report and / or L1 measurement report 324, DU 174 determines that UE 102 should perform an LTM cell handover to the first cell. In response to this determination, DU 174 generates an LTM cell handover command (e.g., MAC CE) including LTM ID 1 and sends a 326 LTM cell handover command to UE 102. In response to this determination, DU 174 can send a 328 DU-CU cell handover notification message to CU 172. In response to the LTM cell handover command, UE 102 performs an LTM cell handover to the first cell. During the LTM cell handover, UE 102 accesses the first cell (332) and sends a 336 RRC reconfiguration complete message to DU 174 via the first cell. DU 174 sends a DU-CU message (e.g., 338) to CU 172, which includes an RRC reconfiguration completion message. UL RRC Messaging (Message). When UE 102 receives an LTM cell handover command, UE 102 identifies LTM candidate configuration 1 from LTM ID 1 and uses LTM candidate configuration 1 to access the first cell (332). Depending on the implementation, in response to the LTM cell handover command, UE 102 may cease communication on the serving cell. Subsequently, DU 174 sends a fifth DU-CU message to CU 172, including an RRC reconfiguration complete message. When DU 174 detects that UE 102 has accessed the first cell in event 332, DU 174 may send an access success message (334) to CU 172 to indicate that UE 102 has accessed the first cell.

[0089] In some implementations, DU 174 includes the TA value used for UL synchronization with the first cell in the LTM cell handover command. In one implementation, DU 174 derives the TA value based on the RA preamble (e.g., the timing of the RA preamble reception). In another implementation, DU 174 derives the TA value from the UL transmission from UE 102 on the serving cell (e.g., cell 124A). UE 102 applies the TA value to synchronize with the first cell in the UL transmission. After applying the TA value, UE 102 transmits the first UL transmission on the first cell based on LTM Candidate Configuration 1 without performing the RA procedure on the first cell. In some implementations, UE 102 uses UL grant to transmit the first UL transmission on the first cell. In this case, the first UL transmission is a PUSCH transmission. In some implementations, the PUSCH transmission includes an RRC reconfiguration complete message 336. In some implementations, the UL grant is a configuration grant, and LTM Candidate Configuration 1 or LTM DU Configuration 1 includes a configuration grant configuration that configures the configuration grant. In other implementations, the UL grant is a dynamic grant received by UE 102 on the PDCCH of the first cell. After sending the first UL transmission, UE 102 receives the PDCCH transmission addressed to UE 102's C-RNTI, and in response to receiving the PDCCH transmission, determines that the LTM cell handover has been successfully completed.

[0090] PDCCH transmissions may include UL grants or DL ​​assignments. In the case of UL grants, UE 102 uses the UL grant to send a PUSCH transmission to DU 174 on the first cell. In the case of DL assignments, DU 174 sends a PDSCH transmission to UE 102 on the first cell according to the DL assignment. After receiving the first UL transmission, sending a PDCCH transmission, receiving a PUSH transmission, or sending a PDSCH transmission (e.g., in response to these operations), DU 174 may send an Access Success 334 message to CU 172.

[0091] In other implementations, DU 174 does not include the TA value in the LTM cell handover command. If the LTM cell handover command does not include the TA value, UE 102 performs a 332 RA procedure on the first cell according to the RA configuration parameters. In some implementations, the RA configuration parameters are included in LTM candidate configuration 1 or LTM DU configuration 1. In some implementations, the RA configuration parameters configure PRACH resources, the association between SSB and PRACH resources, and / or one or more PRACH timings. If UE 102 successfully completes the RA procedure, UE 102 determines that the LTM cell handover to the first cell has been successfully completed. Depending on the implementation and / or the RA configuration parameters, the RA procedure can be a four-step RA procedure or a two-step RA procedure. During a four-step RA procedure, in response, UE 102 sends message 3 on the first cell, and DU 174 sends message 4 to UE 102 on the first cell. During the two-step RA procedure, in response, UE 102 sends message A on the first cell, and DU 174 sends message B to UE 102 on the first cell. UE 102 may include the RRC reconfiguration complete message 336 in message 3 or message A. Alternatively, UE 102 sends the RRC reconfiguration complete message 336 after completing the RA procedure. After receiving message 3, message A, or the RRC reconfiguration complete message 336, or after sending message 4 or message B, DU 174 may send an access success message 334 to CU 172.

[0092] After successfully completing the LTM cell handover to the first cell as described above, UE 102 communicates with DU 174 and CU 172 via the first cell using LTM candidate configuration 1 340. In the case of the LTM reference configuration, UE 102 first applies the LTM reference configuration and then applies LTM candidate configuration 1 to enhance the LTM reference configuration.

[0093] In some implementations, each TCI state configuration in the TCI state configuration includes a TCI state ID. In some implementations, DU 174 includes a first TCI state ID in the LTM cell handover command, indicating the first TCI state configuration in the TCI state configuration. UE 102 identifies the first TCI state configuration in the TCI state configuration based on the first TCI state ID and applies the first TCI state configuration to communicate UL and / or DL ​​transmissions with DU 174 in events 332, 336, and / or 340. DU 174 applies the first TCI state configuration to communicate UL and / or DL ​​transmissions with UE 102 in events 332, 336, and / or 340.

[0094] In some implementations, before or after sending the LTM cell handover command, or during or after procedures 390 or 392, CU 172 may prepare additional cells (i.e., cells 2, ..., N) as LTM candidate cells for UE 102, as described above, with DU 174. N is an integer greater than 1. For example, CU 172 and DU 174 perform additional LTM preparation procedures 2, ..., N to prepare cells 2, ..., N respectively. Each of LTM preparation procedures 2, ..., N is similar to procedure 390. In LTM preparation procedures 2, ..., N, CU 172 receives LTM DU configurations 2, ..., N for LTM, respectively. CU 172 generates LTM candidate configurations 2, ..., N, respectively, including LTM DU configurations 2, ..., N. CU 172 assigns LTM IDs 2, ..., N to identify LTM DU configurations 2, ..., N and LTM candidate configurations 2, ..., N respectively. CU 172 can obtain CSI resource configurations 2, ..., N, and perform CSI report configuration and / or LTM ID configuration procedures 2, ..., N with DU 174 to obtain CSI report configurations 2, ..., N, as described for CSI resource configuration 1 and CSI report configuration 1, respectively. CU 172 can obtain RACH configurations 2, ..., N for cells 2, ..., N, as described for RACH configuration 1, respectively. CU 172 can obtain TCI status configurations 2, ..., N for cells 2, ..., N, as described for TCI status configuration 1, respectively. Each of the CSI report configuration and / or LTM ID configuration procedures 2, ..., N is similar to procedure 392. CU 172 can obtain LTM SSB configurations 2, ..., N for cells 2, ..., N, as described for LTM SSB configuration 1, respectively. In some implementations, CU 172 may perform LTM configuration delivery procedures 2, ..., N with UE 102 to send the following lists to UE 102 respectively: {LTM ID 2, LTM candidate configuration 2, CSI resource configuration 2 (if obtained), TCI state configuration 2 (if obtained), RACH configuration 2 (if obtained), LTM SSB configuration 2 (if obtained)}, ..., {LTM ID N, LTM candidate configuration N, CSI resource configuration N, TCI state configuration N (if obtained), RACH configuration N (if obtained), LTM SSB configuration N (if obtained)}. Each of the LTM configuration delivery procedures 2, ..., N is similar to procedure 394. In other implementations, CU 172 includes the list in the first RRC reconfiguration message.

[0095] In some implementations, after receiving the 334 Access Success Message or the 338 DU to CU Message, CU 172 may send a 342 CU to DU Message to DU 174. In one implementation, CU 172 sends the 342 CU to DU Message to release the radio resources and / or configurations of the serving cell configured for UE 102. In another implementation, CU 172 sends the 342 CU to DU Message to release some of LTM candidate cells 2, ..., N. In this case, CU 172... In response to the CU to DU Message 342, DU 174 sends a 344 DU to CU 172. In some implementations, the CU to DU Message 342 and the DU to CU Message 344 are respectively... UE Context Modification Request Messages and UE context modification response information.

[0096] In some implementations, the LTM ID, LTM cell handover command, and RRC reconfiguration message in the PDCCH command are represented in different formats. For example, the PDCCH command or LTM cell handover command includes a first field for including LTM ID 1, and the first RRC reconfiguration message includes a second field for including LTM ID 1. In some implementations, the first and second fields have different formats or encoding / decoding schemes. For example, the first field uses a binary format (i.e., 3 bits) with values ​​ranging from 0 to 7, and the second field uses an integer format with values ​​ranging from 1 to 8. In this example, the first field with a binary value of 000b is equivalent to the second field with an integer value of 1, the first field with a binary value of 001b is equivalent to the second field with an integer value of 2, and so on, and the first field with a binary value of 111b is equivalent to the second field with an integer value of 8.

[0097] Events 304, 306, 390, 392, 394, and 324 are in Figure 3 This is collectively referred to as the CU-DU-LTM configuration process 396. Events 304, 306, 390, 392, 394, 324, 350, 352, 354, 326, 328, 332, 334, 336, 338, and 340 are in... Figure 3 The process is collectively referred to as CU-internal DU-internal LTM process 380.

[0098] Next reference Figure 4In scenario 400, base station 104A includes CU 172, S-DU 174A, and candidate DU (C-DU) 174B. S-DU 174A operates cell 124A and optionally operates an additional cell, while C-DU 174B operates the first cell (e.g., cell 124C). Scenario 400 is an inter-DU scenario within a CU, similar to scenario 300. Therefore, the description for scenario 300 can be largely applied to scenario 400. Figure 3 Some descriptions of DU 174 in the document can be applied to Figure 4 S-DU 174A in, and for Figure 3 Some descriptions of DU 174 in the document can be applied to C-DU 174B. The differences between scenarios 300 and 400 are described below.

[0099] Initially, UE 102 uses a serving DU configuration to communicate with S-DU 174A 402 on one or more serving cells (e.g., cell 124A and / or other cells), and a serving CU configuration to communicate with CU 172 via S-DU 174A. In some implementations, CU 172 and S-DU 174A may perform LTM configuration procedure 396 or LTM procedure 380 with UE 102, as for Figure 3 As described above. In the case of procedure 380, UE 102 can perform an LTM cell handover to the first cell (e.g., cell 124B), as for... Figure 3As described above. After a successful LTM cell handover, the first cell becomes the serving cell, and cell 124A and / or other cells are no longer serving cells for UE 102. In the case of procedure 396, UE 102 does not perform an LTM cell handover. During communication 402, UE 102 sends at least one measurement report (e.g., an L3 measurement report) via S-DU 174A to CU 172 in steps 404 and 406. Based on the measurement report, CU 172 determines to prepare cell 1 (e.g., cell 124C operated by C-DU 174B) for UE 102 for LTM. Cell 1 is identified by a cell ID (i.e., cell ID 1). In response to this determination, CU 172 and C-DU 174B perform LTM preparation procedure 490 to (request C-DU 174B) prepare cell 1 as an LTM candidate cell for UE 102. In LTM preparation process 490, CU 172 sends a first CU-DU message to C-DU 174B, including cell ID 1 of cell 1, to request C-DU 174B to prepare cell 1 as an LTM candidate cell for UE 102, similar to event 308. In response, C-DU 174B sends a first DU-CU message to CU 172, including the LTM DU configuration (e.g., LTM DU configuration 1), similar to event 310. CU 172 may or may not request the LTM reference DU configuration in the first CU-DU message, as for... Figure 3 The C-DU 174B may or may not include the LTM reference DU configuration in the first DU to CU message, as described above. Figure 3 As stated above.

[0100] In some implementations, if CU 172 receives LTM reference DU configuration from S-DU 174A, such as for... Figure 3 As described above, CU 172 may include an LTM reference DU configuration in the first CU-DU message, and C-DU 174B may generate an LTM DU configuration as an incremental configuration based on the LTM reference DU configuration. In this case, C-DU 174B does not send the LTM reference DU configuration for UE 102 to CU 172. In other implementations, CU 172 receives the LTM reference DU configuration from C-DU 174B, for example, in the first DU-CU message or an additional DU-CU message, as for... Figure 3 As described above. In such a case, CU 172 can generate an LTM reference configuration that includes the LTM reference DU configuration. CU 172 may or may not include the LTM reference CU configuration in the LTM reference configuration.

[0101] To prepare cell 1 for LTM, CU 172 can perform LTM CSI report configuration and / or LTM ID configuration procedure 492 with S-DU 174A. In procedure 492, CU 172 sends a second CU-DU message to S-DU 174A, including a CSI resource configuration (e.g., CSI resource configuration 1) and / or an LTM SSB configuration (i.e., LTM SSB configuration 1), similar to event 312. In response, S-DU 174A sends a second DU-CU message to CU 172, including one or more CSI report configurations (e.g., CSI report configuration 1). In some implementations, CU 172 generates an LTM candidate configuration (e.g., LTM candidate configuration 1) including an LTM DU configuration and assigns an LTM ID (e.g., LTM ID 1) to identify the LTM DU configuration and / or LTM candidate configuration, as per the example for LTM DU configurations. Figure 3 As described above. In some implementations, CU 172 includes {LTM ID 1, Cell ID 1} as a tuple in the second CU to DU message.

[0102] To prepare cell 1 as an LTM candidate cell for UE 102, CU 172 can receive early synchronization information for cell 1 from C-DU 174B in a DU-CU message (e.g., a first DU-CU message or an additional DU-CU message). In some implementations, C-DU 174B sends an additional DU-CU message in response to receiving an additional DU-CU message from CU 172. In other implementations, C-DU 174B sends an additional DU-CU message in response to receiving a first CU-DU message (e.g., ...). UE context modification requirements Message). Early synchronization information includes RACH configuration (e.g., RACH configuration 1) and / or at least one TCI state configuration (e.g., TCI state configuration 1), as for... Figure 3 As described above. In some implementations, the C-DU 174B includes PDCCH command information (PDCCH command information 1) in the early synchronization information or in the DU to CU message to achieve early UL synchronization with the first cell.

[0103] In some implementations, CU 172 may receive LTM SSB configuration or SSB configuration parameters in the LTM SSB configuration from C-DU 174B, for example, in a first DU-CU message or an additional DU-CU message. In some implementations, CU 172 may receive the PCI of cell 1 from C-DU 174B in a first DU-CU message or an additional DU-CU message. In some implementations, C-DU 174B sends an additional DU-CU message in response to receiving an additional DU-CU message from CU 172. In other implementations, C-DU 174B sends an additional DU-CU message in response to receiving a first CU-CU message (e.g., ...). UE context Modification requirements information).

[0104] For example, regarding Figure 3 As described above, CU 172 and UE 102 execute LTM configuration delivery procedure 494 to send LTMID 1 and LTM candidate configuration to UE 102. In some implementations, in procedure 494, CU 172 sends {LTM ID, LTM candidate configuration} as a tuple in the first RRC reconfiguration message. Depending on the implementation, CU 172 may include the LTM reference configuration, CSI report configuration, CSI resource configuration, RACH configuration, TCI status configuration, LTM SSB configuration, and / or PCI for cell 1 to UE 102 in the first RRC reconfiguration message and / or other RRC reconfiguration messages sent to UE 102, such as for... Figure 3 The CU 172 includes an LTM ID in the first RRC reconfiguration message or other RRC reconfiguration messages to indicate that the CSI resource configuration, RACH configuration, TCI state configuration, LTM SSB configuration, and / or the PCI of cell 1 are associated with cell 1. For example, the CU 172 includes the CSI resource configuration, RACH configuration, TCI state configuration, LTM SSB configuration, and / or the PCI of cell 1 in a tuple. In another example, the CU 172 includes {LTM ID, CSI resource configuration, RACH configuration, TCI state configuration, LTM SSB configuration, and / or the PCI of cell 1} as a tuple in other RRC reconfiguration messages. In response to each RRC reconfiguration message in other RRC reconfiguration messages, the UE 102 sends an RRC reconfiguration complete message to the CU 172 via the S-DU 174A.

[0105] In some implementations, the PDCCH command information includes frequency domain resource assignment, RA preamble index, UL or supplementary UL indicator, SSB index, and / or physical RACH mask index. CU 172 can send a CU-DU message (e.g., a second CU-DU message or an additional CU-DU message) including the PDCCH command information to S-DU 174A. In some implementations, CU 172 includes LTM ID 1 or cell ID 1 in the CU-DU message to indicate that the PDCCH command information is associated with LTM ID 1 or cell ID 1. For example, CU 172 includes {cell ID 1, PDCCH command information} as a tuple in the CU-DU message. In the case of an additional CU-DU message, S-DU 174A can send an additional DU-CU message to CU 172 in response. S-DU 174A sends a 450 PDCCH command to UE 102 based on the PDCCH command information. For example, S-DU 174A sends a PDCCH command (450) including PDCCH command information to UE 102. In some implementations, S-DU 174A may determine the SSB index included in the PDCCH command based on L1 Measurement Report (424), and / or CSI Resource Configuration, CSI Report Configuration, and / or LTM SSB Configuration. In some implementations, S-DU 174A includes LTM ID 1 in the PDCCH command to indicate cell 1. In the case of an appended CU to DU message, S-DU 174A may send an appended DU to CU message to CU 172 in response. UE 102 uses RACH configuration and / or PDCCH command information to send a RA preamble (452) to C-DU 174B on cell 1. C-DU 174B derives the TA value based on the RA preamble. C-DU 174B sends a DU-CU TA information delivery message (456) including the TA value to CU 172. CU 172 then sends a CU-DU TA information transmission message (458) including the TA value to S-DU 174A. In some implementations, C-DU 174B includes cell ID 1, RA preamble index, RA radio network temporary identifier (RA-RNTI), and / or the DU ID of S-DU 174A in message 456. In such cases, CU 172 includes cell ID 1, RA preamble index, RA-RNTI, and / or the DU ID of S-DU 174A in message 458. In response to the determination command UE 102 to perform an LTM cell handover to cell 1, S-DU 174A sends an LTM cell handover command (456) including LTM ID 1 to UE 102. If S-DU 174A receives the TA value as described above, S-DU 174A may include the TA value in the LTM cell handover command.The S-DU 174A can include the first TCI state ID in the LTM cell handover command. The first TCI state ID indicates the first TCI state configuration in the TCI state configuration.

[0106] In some implementations, the C-DU 174B determines the RA-RNTI based on the PRACH timing of the RA preamble 452 received by the C-DU 174B. In some implementations, the C-DU 174B calculates the RA-RNTI as follows:

[0107] Wherein, s_id is the index of the first OFDM symbol of the PRACH timing (0 ≤ s_id < 14), t_id is the index of the first slot of the PRACH timing in the system frame (0 ≤ t_id < 80), where for μ={0, 1, 2, 3}, the subcarrier spacing used to determine t_id is based on the value of μ specified in Clause 5.3.2 of 3GPP TS 38.211, and for μ={5,6}, t_id is the index of the 120 kHz slot in the system frame containing the PRACH timing (0 ≤ t_id < 80), f_id is the index of the PRACH timing in the frequency domain (0 ≤ f_id < 8), and ul_carrier_id is the UL carrier used for RA preamble transmission (0 for NUL carrier and 1 for SUL carrier).

[0108] In response to the confirmation command UE 102 to perform LTM cell handover or send LTM cell handover command 456, S-DU174A sends 428 to CU 172. DU-CU cell handover notification The message instructs UE 102 to perform an LTM cell handover to cell 1. In response, CU 172 sends a 430 message to C-DU 174B. CU-DU Cell Handover Notification The message instructs UE 102 to perform an LTM cell handover to cell 1. In some implementations, the S-DU 174A includes the first TCI state ID. DU-CU community switching Change notification The message, and CU 172 subsequently included the first TCI status ID. CU-DU Cell Handover Notification In the message, UE102 and C-DU 174B identify the first TCI state configuration in the TCI state configuration based on the first TCI state ID, and apply the first TCI state configuration to communicate UL transmissions and / or DL ​​transmissions in events 432, 436 and / or 440.

[0109] In some implementations, each TCI state configuration in the TCI state configuration includes a TCI state ID or is associated with that TCI state ID. In some implementations, CU 172 may send a CU-DU message (e.g., a second CU-DU message or an additional CU-DU message) to S-DU 174A that includes the TCI state configuration and / or the associated TCI state ID. In some implementations, CU 172 includes LTM ID 1 or Cell ID 1 in the CU-DU message to indicate that the TCI state configuration is associated with LTM ID 1 or Cell ID 1. For example, CU 172 includes {Cell ID 1, TCI state configuration} as a tuple in the CU-DU message. In the case of an additional CU-DU message, S-DU 174A may send an additional DU-CU message to CU 172 in response. In some implementations, S-DU 174A includes a first TCI state ID indicating the first TCI state configuration in the TCI state configuration in the LTM cell handover command 426. In some implementations, S-DU 174A determines the first TCI state configuration or the first TCI state ID. UE 102 identifies a TCI state configuration based on the first TCI state ID and applies the first TCI state configuration in UL transmission and / or DL ​​reception in events 432, 436, and / or 440.

[0110] In some implementations, before or after sending the LTM cell handover command, or during or after procedures 490 or 492, CU 172 may prepare additional cells (i.e., cells 2, ..., N) with C-DU 174B as LTM candidate cells for UE102, such as for... Figure 4 As stated above.

[0111] In some implementations, the first CU to DU message and the first DU to CU message are UE Context Establishment Request Messages and UE Context Establishment Response Messages. In some implementations, the first CU to DU message and the first DU to CU message are... UE Request for amendments Messages and UE context modification response In some implementations, LTM preparation procedure 490 is a UE context establishment procedure, and the additional LTM preparation procedure is a UE context modification procedure. In other implementations, LTM procedure 490 and the additional LTM preparation procedure are both UE context establishment procedures. In yet another implementation, LTM procedure 490 and the additional LTM preparation procedure are both UE context modification procedures.

[0112] Events 404, 406, 490, 492, 494, 494, and 424 are in Figure 4This is collectively referred to as the CU-DU inter-LTM configuration process 496. Events 404, 406, 490, 492, 494, 494, 424, 450, 452, 454, 456, 458, 426, 428, 430, 432, 434, 436, 438, 440, 442, and 444 are in... Figure 4 This is collectively referred to as the CU-internal DU-internal LTM process 480.

[0113] Next reference Figure 5 In scenario 500, base station 104A operates as a serving or source base station (S-BS), and base station 106A operates as a candidate base station (C-BS). C-BS 106A includes CU 172 and DU 174. Scenario 500 is similar to scenarios 300 and 400, except that scenario 500 is an inter-CU scenario (i.e., an inter-base station scenario), while scenarios 300 and 400 are intra-CU scenarios (i.e., intra-base station scenarios). S-BS 104A may include CU and DU (…). Figure 5 (not shown in the image), similar to Figure 3 and Figure 4 The base station 104A. Initially, UE 102 communicates with S-BS 104A via the serving cell using the service configuration 502. In some implementations, S-BS 104A includes S-DU and CU, and the service configuration may include service CU configuration and service DU configuration, such as for... Figure 3 and Figure 4 As described above. When communicating with UE 102 502, S-BS 104A may perform an in-CU LTM procedure 580 with UE 102, similar to procedures 380 and / or 480. Alternatively, when communicating with UE 102 502, S-BS 104A may perform an in-CU LTM configuration procedure 596 with UE 102, similar to procedures 396 and / or 496.

[0114] When communicating with S-BS 104A, UE 102 sends at least one measurement report (504) to S-BS 104A. The measurement report includes measurement results for UE 102's serving cell and / or at least one non-serving cell (e.g., cell 126A). Based on the measurement report, S-BS 104A determines a first cell (e.g., cell 126A) to be prepared as an LTM candidate cell for UE 102. For example, the measurement report includes the PCI of the first cell and the measurement results for cell 126A. S-BS 104A identifies the first cell as being operated by base station 106A based on the PCI and determines the first cell is eligible for LTM preparation based on the measurement results.

[0115] After determining that the first cell is to be prepared as an LTM candidate cell for UE 102 (e.g., in response to determining that the first cell is to be prepared as an LTM candidate cell for UE 102), S-BS 104A (e.g., the CU of S-BS 104A) generates a first cell ID (i.e., cell ID 1) including the first cell (i.e., cell 1). Switching requests Message. S-BS 104A sends 505 to CU 172. Switching requests Message. In some implementations, Switching requests The message includes instructions Switching requests The message contains an LTM indicator for the LTM used for the first cell ID. Upon receiving... Switching requests Following the message (e.g., in response to receiving a handover request message), CU 172 and DU 174 perform LTM preparation procedure 590 to prepare a first cell as an LTM candidate cell for UE 102, similar to procedure 390 or 490. In procedure 590, CU 172 sends a first CU-DU message including the first cell ID to DU 174 to request preparation of the first cell, similar to event 308. In response, CU 172 can receive a first DU-CU message including LTMDU configuration 1 from DU 174, similar to event 310. CU 172 generates a first LTM candidate configuration (LTM candidate configuration 1). In response to Switching requests Message: CU 172 sends 507 to S-BS 104A, including the first LTM candidate configuration. Switching requests should answer Message. In some implementations, CU 172 includes the first cell ID. Switching between request and response The message indicates that the first LTM candidate configuration is provided for or associated with the first cell (ID).

[0116] Events 505, 590, and 507 are in Figure 5 This is collectively referred to as the CU-interval LTM preparation process (or the MN-interval LTM preparation process) 598.

[0117] In some implementations, Switching requests The message includes the DU ID of the S-DU of S-BS 104A. In such cases, CU 172 includes the DU ID in the first CU-DU message. In some implementations, Switching requests The message includes the BS ID of S-BS104A. When the BS ID is received, CU 172 can include the BS ID in the first CU to DU message. For example, the BS ID is the gNB ID.

[0118] CU 172 may or may not request the LTM reference DU configuration in procedure 590, as for... Figure 3 and Figure 4 As stated above. DU174 may or may not send the LTM reference DU configuration to CU 172 in process 590, as for... Figure 3 and Figure 4 As described above. In some implementations, the S-BS 104A (e.g., the CU of the S-BS 104A) can obtain an LTM reference configuration, such as for... Figure 3 and Figure 4 As described above. In other implementations, the S-BS 104A can be transferred from another BS (as described above and below) during another CU-to-CU LTM preparation process. Figure 5 (Not shown in the image) Receives the LTM reference configuration. If the S-BS 104A obtains the LTM reference configuration, the S-BS 104A can include the LTM reference configuration (the LTM reference configuration generated by the S-BS) in... Switching requests In some implementations, S-BS 104A includes the LTM reference configuration in the inter-node RRC message. HandoverPreparationInformation The Xn Application Protocol (XnAP) IE or field is included in the XnAP IE, and the inter-node RRC message or XnAP IE is also included. Switching requests The message states that, alternatively, S-BS 104A determines whether to request or cause C-BS 106A to provide a complete LTM candidate configuration, enabling S-BS104A to... Switching requests The message does not include the LTM reference configuration. If the S-BS 104A does not obtain the LTM reference configuration, the S-BS 104A will not include the LTM reference configuration in the message. Switching requests In the message. If Switching requests If the message includes an LTM reference configuration, CU172 can include the LTM reference configuration in the first CU-DU message. DU 174 can extract the LTM reference DU configuration from the LTM reference configuration. Alternatively, CU 172 extracts the LTM reference DU configuration from the LTM reference configuration and includes it in the first CU-DU message. DU 174 can generate an LTM DU configuration as an incremental configuration based on the LTM reference DU configuration, such as for... Figure 3 Alternatively, DU 174 can ignore the LTM reference (DU) configuration and generate the LTM DU configuration as a complete configuration, as described above. Figure 3 As stated above.

[0119] Otherwise, if Switching requests If the message does not include the LTM reference configuration, then CU 172 may or may not receive the LTM reference DU configuration from DU 174, as for... Figure 3As described above. If CU 172 receives an LTM reference DU configuration (e.g., in the first DU to CU message), then CU 172 generates an LTM reference configuration that includes the LTM reference DU configuration (the LTM reference configuration generated by the C-BS). CU 172 may include an LTM reference CU configuration (the LTM reference CU configuration generated by the candidate CU (C-CU)). Otherwise, if CU 172 does not receive an LTM reference DU configuration from DU 174, as for... Figure 3 In this case, CU 172 does not generate an LTM reference configuration. Instead, CU 172 generates an LTM reference configuration (C-BS generated LTM reference configuration) that only includes the LTM reference CU configuration generated by C-CU. When CU 172 generates an LTM reference configuration (C-BS generated LTM reference configuration), CU 172 includes the C-BS generated LTM reference configuration. Switching between request and response In the message.

[0120] In some implementations, if LTM DU configuration 1 is a complete configuration, then CU 172 generates LTM candidate configuration 1 as the complete configuration. CU 172 can... Switching between request and response The message includes a full configuration indication (e.g., the BS-to-BS interface protocol field / IE) to indicate that LTM candidate configuration 1 is a full configuration. In some implementations, the BS-to-BS interface protocol is the Xn application protocol defined in 3GPP specification 38.423. In some implementations, the full configuration indication is a new field / IE (e.g., LTM-specific) to avoid impacting non-LTM configurations. In other implementations, the full configuration indication is an existing field / IE defined in 3GPP specification 38.423. Otherwise, if LTM DU configuration 1 is an incremental configuration, CU 172 generates LTM candidate configuration 1 as an incremental configuration. CU 172 can obtain... Switching between request and response The message excludes the full configuration indication to indicate that LTM candidate configuration 1 is an incremental configuration. Alternatively, CU 172 can... Switching between request and responseThe message includes an incremental configuration indication (e.g., the BS-to-BS interface protocol field / IE) to indicate that LTM candidate configuration 1 is an incremental configuration. In some implementations, the BS-to-BS interface protocol is the Xn application protocol defined in 3GPP specification 38.423. In some implementations, the incremental configuration indication is a new field / IE (e.g., LTM-specific) to avoid impacting non-LTM configurations. In other implementations, the incremental configuration indication is an existing field / IE defined in 3GPP specification 38.423. In some implementations, the BS-to-BS interface protocol field / IE has two values ​​(i.e., a first value and a second value). The BS-to-BS interface protocol field / IE set to the first value is a full configuration indication, and the BS-to-BS interface protocol field / IE set to the second value is an incremental configuration indication.

[0121] In some implementations, the S-BS 104A is pre-configured with CSI resource configuration (e.g., (LTM) CSI resource configuration 1) and / or LTM SSB configuration (LTM SSB configuration 1) for the first cell. In other implementations, the S-BS 104A receives the CSI resource configuration and / or LTM SSB configuration from the OAM (Operation, Administration, and Maintenance) node. In yet another implementation, the S-BS 104A receives the CSI resource configuration and / or LTM SSB configuration from the CU 172. For example, the CU 172 includes the CSI resource configuration and / or LTM SSB configuration in... Switching between request and response The message states that in some implementations, CU 172 includes the PCI (PCI 1) of the first cell. Switching between request and response In the message, to prepare the first cell as a candidate LTM cell for UE 102, the CU of S-BS 104A and the S-DU of S-BS 104A perform the LTM CSI report configuration and / or LTM ID configuration procedures. Figure 5 (Not shown in the diagram), similar to procedure 392. During the LTM CSI report configuration and / or LTM ID configuration process, the CU of S-BS 104A sends the CSI resource configuration and / or LTM SSB configuration to the S-DU of S-BS 104A. In response, the CU of S-BS 104A receives one or more CSI report configurations for UE 102 from the S-DU of S-BS 104A. In some implementations, the CU of S-BS 104A receives the CSI report configuration in a second service DU configuration from the S-DU.

[0122] To prepare the first cell as an LTM candidate cell for UE 102, CU 172 can receive early synchronization information (early synchronization information 1) for the first cell from DU 174 in a DU-CU message (e.g., a first DU-CU message or an additional DU-CU message). In some implementations, DU 174 sends an additional DU-CU message in response to receiving an additional DU-CU message from CU 172. In other implementations, DU 174 sends an additional DU-CU message (e.g., in response to receiving a first CU-CU message) in response to receiving a first CU-CU message. UE context modification requirements (Message). CU 172 in Switching between request and response The message includes early synchronization information. This early synchronization information includes RACH configuration (RACH configuration 1) and / or at least one TCI state configuration (TCI state configuration 1). In some implementations, DU 174 includes PDCCH command information in the early synchronization information or in the DU-to-CU message for early UL synchronization with the first cell. CU 172 in Switching between request and response The message includes PDCCH command information.

[0123] In some implementations, CU 172 assigns an LTM ID (e.g., LTMID 1) to identify the first LTM candidate configuration, and in Switching between request and response The message includes the LTM ID. In other implementations, S-BS 104A assigns an LTM ID (e.g., LTM ID 1) to identify the first LTM candidate configuration.

[0124] Received Switching between request and response Following the message (e.g., in response to receiving a handover request response message), the S-BS104A (e.g., the CU of the S-BS104A) sends a first RRC reconfiguration message, 518, to the UE 102, including {LTM ID 1, LTM candidate configuration 1} as a tuple, similar to event 318. If Switching between request and response If the message includes the LTM reference configuration, the S-BS104A can include the LTM reference configuration in the first RRC reconfiguration message. If in Switching between request and responseIf the message receives CSI Resource Configuration 1, TCI State Configuration 1, RACH Configuration 1, and / or LTM SSB Configuration 1, the S-BS 104A may include these configurations in the tuple. Alternatively, the S-BS 104A sends one or more additional RRC reconfiguration messages to the UE 102, including CSI Resource Configuration 1, TCI State Configuration 1, RACH Configuration 1, LTM SSB Configuration 1, and / or the PCI of the first cell. In each of the additional RRC reconfiguration messages, the S-BS 104A includes LTM ID 1 to indicate that CSI Resource Configuration 1, TCI State Configuration 1, RACH Configuration 1, LTM SSB Configuration 1, and / or the PCI of the first cell are associated with or configured for the first cell. In response to the first RRC reconfiguration message, the UE 102 sends a 520 First RRC Reconfiguration Complete Message to the S-BS 104A. In response to each RRC reconfiguration completion message in the supplementary RRC reconfiguration completion message, UE 102 sends an additional RRC reconfiguration completion message to S-BS 104A. The RRC reconfiguration messages (i.e., the first RRC reconfiguration message and / or the supplementary RRC reconfiguration message) and the RRC reconfiguration completion messages (i.e., the first RRC reconfiguration completion message and / or the supplementary RRC reconfiguration completion message) form the LTM configuration delivery process. S-BS 104A may include the second service DU configuration in the first RRC reconfiguration message or one or more supplementary RRC reconfiguration messages.

[0125] In some implementations, if Switching between request and response If the message includes a complete configuration indication indicating that LTM candidate configuration 1 is a complete configuration, then S-BS 104A will include the complete configuration indication (e.g., the RRC field / IE) in the first RRC reconfiguration message to indicate that LTM candidate configuration 1 is a complete configuration. Otherwise, if Switching between request and response If the message does not include a full configuration indication or includes an incremental configuration indication to indicate that LTM candidate configuration 1 is an incremental configuration, then S-BS 104A excludes or does not include a full configuration indication (e.g., RRC field / IE) to indicate that LTM candidate configuration 1 is an incremental configuration in the first RRC reconfiguration message.

[0126] if Switching between request and responseIf the message includes PDCCH command information (PDCCH command information 1), then S-BS 104A sends a 550 PDCCH command based on this PDCCH command information. If S-BS 104A is a distributed base station, then the CU of S-BS 104A can send the PDCCH command information to the S-DU of S-BS 104A. For example, S-BS 104A or its S-DU sends a 550 PDCCH command including the PDCCH command information to UE 102. In some implementations, S-BS 104A or its S-DU can determine the SSB index included in the PDCCH command based on L1 measurement report 524, and / or CSI resource configuration, CSI report configuration, and / or LTM SSB configuration. In some implementations, S-DU or S-BS 104A includes LTM ID 1 in the PDCCH command to indicate the first cell. UE 102 uses RACH configuration and / or PDCCH command information to send a 552 RA preamble to DU 174 on the first cell. S-DU or S-BS 104A derives the TA value based on the RA preamble. DU 174 then sends a 556 RA preamble containing the TA value to CU 172. DU-CU TA Information Transmission Message. CU 172 sends CU-CU TA information transmission message 558, including the TA value, to S-SB 104A (e.g., the CU of S-BS 104A). In some implementations, DU 174 includes cell ID 1, RA preamble index, RA-RNTI, DU ID of S-DU of S-BS 104A, and / or BS ID of S-BS 104A in message 556. In some implementations, DU 174 does not include the BS ID in message 556. In some implementations, CU 172 includes cell ID 1, RA preamble index, RA-RNTI, DU ID of S-DU, and / or BS ID of S-BS 104A in message 558. In some implementations, CU 172 does not include the BS ID in message 558. The CU of S-BS 104A sends to the S-DU of S-BS 104A a message including the TA value, cell ID 1, RA preamble index, RA-RNTI, and / or the DU ID of the S-DU and / or the BS ID of the S-BS 104A. CU-DU TA Information Transmission Message. In some implementations, the S-BS 104A's CU is in CU-DU TA Information Transmission The message does not include the BS ID.

[0127] In some implementations, CU 172 determines the address (e.g., IP address) of the S-BS 104A or its CU based on the BS ID of the S-BS 104A. In other implementations, CU 172 determines the address (e.g., IP address) of the S-BS 104A or its CU based on the DU ID of the S-DU of the S-BS 104A. Using these implementations, CU 172 sends data to the S-BS 104A or its CU according to the address. CU-CU TA Information Transmission information.

[0128] In response to, for example, determining based on measurement reports 524 and / or 554, that UE 102 should perform an LTM cell handover to a first cell, S-DU or S-BS 104A sends an LTM cell handover command 526, including LTM ID 1, to UE 102. In response to the LTM cell handover command, UE 102 may cease communication on the serving cell. In response to the LTM cell handover command, UE 102 accesses the first cell 532 and sends an RRC reconfiguration complete message 536 to DU 174. DU 174 then sends a DU-CU message 538, including the RRC reconfiguration complete message, to CU 172. After receiving the DU-CU message 538 or the RRC reconfiguration complete message, C-BS 106A communicates with UE 102 540 according to the first LTM candidate configuration and / or LTM reference configuration. In some implementations, UE 102 includes LTM ID 1 in the RRC reconfiguration complete message 536 to indicate that UE 102 applies a first LTM candidate configuration. Based on LTM ID 1, CU 172 identifies the first LTM candidate configuration and / or the LTM reference configuration. In other implementations, CU 172 is based on... Connection successful The first cell ID in message 534 is used to identify the first LTM candidate configuration and / or LTM reference configuration. In this implementation, CU 172 maintains or stores the association information between the first cell ID and the first LTM candidate configuration and / or LTM reference configuration. When CU 172... Connection successful When the first cell ID is received in the message, CU 172 identifies the first LTM candidate configuration and / or LTM reference configuration based on the first cell ID and associated information.

[0129] In some implementations, if the S-DU or S-BS 104A receives a TA value, as described above, the S-DU or S-BS 104A may include the TA value in the LTM cell handover command. In some implementations, the S-DU or S-BS 104A includes a first TCI state ID in the LTM cell handover command. The first TCI state ID indicates the first TCI state configuration in the TCI state configuration.

[0130] In response to the confirmation command UE 102 to perform LTM cell handover or to send LTM cell handover command 526, the S-DU of S-BS104A sends a message to the CU of S-BS104A. DU-CU cell handover notification The message indicates that UE 102 is performing or in the process of an LTM cell handover to the first cell. In response to receiving... DU-CU cell handover notification Message: CU of S-BS 104A sends 527 to CU172 CU-CU cell handover notification The message instructs UE 102 to perform an LTM cell handover to the first cell. In response, CU 172 sends 530 to DU 174. CU-DU Cell Handover Notification The message instructs UE 102 to perform an LTM cell handover to the first cell. In some implementations, S-BS 104A includes the first TCI state ID. CU-CU cell handover notification In the message, CU 172 then includes the first TCI status ID. CU-DU Cell Handover Notification In the message, UE 102 and DU174 identify the first TCI state configuration in the TCI state configuration based on the first TCI state ID, and apply the first TCI state configuration to communicate UL transmissions and / or DL ​​transmissions in events 532, 536 and / or 540.

[0131] In some implementations, the UE 102 determines whether to execute an LTM cell handover, send an LTM cell handover command (526), ​​or receive a command (527). DU-CU cell handover notification Following the message (e.g., in response to a command to UE 102 to perform an LTM cell handover, sending a 526 LTM cell handover command, or receiving a 527 DU-CU cell handover notification message), S-BS 104A (e.g., the CU of S-BS 104A) sends one or more 531 messages to CU 172. Early state transfer Each early state delivery message includes the DL COUNT value or DISCARD DL COUNT value of the DRB used by UE 102 and S-BS 104A to transmit 502 data to each other. In some implementations, upon receiving 534... Connection successfulUpon receiving either a 538 DU to CU message or an RRC reconfiguration complete message, CU 172 sends a 539 LTM success message to S-BS 104A (e.g., the CU of S-BS 104A) to indicate that the LTM cell handover has been successfully completed. In some implementations, the LTM success message is... Switching successful In some implementations, CU 172 includes the first cell ID in the LTM success message. In other implementations, CU 172 does not send a BS-to-BS message to S-BS104A (e.g., the CU of S-BS 104A) to indicate that the LTM cell handover has been successfully completed.

[0132] In some implementations, the UE 102 determines whether to execute LTM cell handover, sends the 526 LTM cell handover command, and receives the 527 command. DU-CU cell handover notification After receiving the 539 LTM success message (e.g., in response to a confirmation command UE 102 performing an LTM cell handover, sending the 526 LTM cell handover command, receiving the 527 DU-CU cell handover notification message, or receiving the 539 LTM success message), S-BS 104A (e.g., the CU of S-BS 104A) sends 541 to CU 172. SN status transmission Delivery The SN status transmission message includes the DL COUNT value and / or UL COUNT value of the DRB used by UE 102 and S-BS 104A to transmit 502 data to each other.

[0133] In some implementations, when receiving 534 to Connection successful Message, receive 538 to DU to CU message or RRC reconfiguration complete message or receive 541 to SN status transmission Following the message (e.g., in response to receiving a 534 message to access success, a 538 message to DU to CU, an RRC reconfiguration complete message, or a 541 message to SN status transfer), CU 172 sends 543 to S-BS104A. UE context release Message. Response to UE context release The message indicates that S-BS 104A releases the UE context of UE 102.

[0134] In some implementations, before or after sending the LTM cell handover command, or during or after procedure 598, S-BS 104A (e.g., the CU of S-BS 104A) may utilize CU 172 to prepare additional cells (i.e., cells 2, ..., N) as LTM candidate cells for UE 102, as described above. Cells 2, ..., N are identified by cell IDs 2, ..., N, respectively, and are operated by DU 174 and / or other DUs of C-BS 106A. N is an integer greater than 1. For example, S-BS 104A performs additional inter-CU LTM preparation procedures 2, ..., N with CU 172 to prepare cells 2, ..., N, respectively. Each of the inter-CU LTM preparation procedures 2, ..., N is similar to procedure 598. In the inter-CU LTM preparation procedures 2, ..., N, S-BS 104A receives LTM candidate configurations 2, ..., N for LTM, respectively. As described above, S-BS 104A or C-BS106A assigns LTM IDs 2, ..., N to identify LTM candidate configurations 2, ..., N, respectively. S-BS 104A can obtain CSI resource configurations 2, ..., N for cells 2, ..., N, as described for CSI resource configuration 1. S-BS 104A can obtain CSI report configurations 2, ..., N or cells 2, ..., N, as described for CSI report configuration 1. S-BS 104A can obtain RACH configurations 2, ..., N for cells 2, ..., N, as described for RACH configuration 1. S-BS 104A can obtain TCI status configurations 2, ..., N for cells 2, ..., N, as described for TCI status configuration 1. S-BS 104A can obtain LTM SSB configurations 2, ..., N for cells 2, ..., N, as described for LTM SSB configuration 1. The S-BS104A can obtain PCI 2, ..., N for cells 2, ..., N, as described for PCI 1. In some implementations, the S-BS 104A can perform LTM configuration delivery procedures 2, ..., N with UE 102 to send the following list to UE 102: {LTM ID 2, LTM candidate configuration 2, CSI resource configuration 2 (if obtained), TCI state configuration 2 (if obtained), RACH configuration 2 (if obtained), LTM SSB configuration 2 (if obtained), PCI 2 (if obtained)}, ..., {LTM ID N, LTM candidate configuration N, CSI resource configuration N, TCI state configuration N (if obtained), RACH configuration N (if obtained), LTM SSB configuration N (if obtained), PCI N (if obtained)}.Each of the LTM configuration delivery procedures 2, ..., N is similar to procedures 394, 494, and / or 594. In other implementations, S-BS 104A includes the list in the first RRC reconfiguration message.

[0135] In other implementations, S-BS 104A performs the same process 598 as CU 172 to prepare one or more cells from cell 1, ..., N as LTM candidate cells for UE 102. In such an implementation, S-BS 104A is used for LTM... Switching requests Message 505 includes cell ID 1, ..., N, as described for cell ID 1. In some implementations, upon receiving... Switching requests When a message is received, CU 172 determines or selects cells 1, ..., N as LTM candidate cells. M is a positive integer and M ≤ N. In other implementations, CU 172... Switching requests The message requests the preparation of cells 1, ..., N for LTM. CU 172 and DU 172 execute LTM preparation procedures 2, ..., M to prepare cells 2, ..., M as LTM candidate cells for UE 102, respectively. LTM preparation procedures 2, ..., M are similar to procedure 590 executed by CU 172 and DU 174 to prepare cell 1. CU 172 obtains LTM candidate configurations 2, ..., M for cells 2, ..., M as the result of LTM preparation procedures 2, ..., M, similar to obtaining LTM candidate configuration 1. C-BS 106A can generate LTM candidate configurations 2, ..., M as a complete configuration, or generate incremental configurations based on the LTM reference configuration, as described for LTM candidate configuration 1. CU 172 in Switching between request and response The message includes LTM candidate configurations 2, ..., M. In some implementations, CU 172 or S-BS 104A assigns LTM IDs 2, ..., M to identify LTM preparation processes 2, ..., M respectively, as described for LTM ID 1. When CU 172 assigns LTM IDs 1, ..., M, CU 172... Switching between request and response The messages include LTMID 1, ..., M and LTM candidate configuration 1, ..., M, as described for LTM ID 1 and LTM candidate configuration 1.

[0136] In some implementations, CU 172 obtains early synchronization information 2, ..., M for cells 2, ..., M respectively, as described for early synchronization information 1. CU 172 includes the early synchronization information 2, ..., M in... Switching between request and responseIn some implementations, CU 172 or S-BS 104A obtains CSI resource configurations 2, ..., M for cells 2, ..., M, as described for CSI resource configuration 1. When CU 172 obtains CSI resource configurations 2, ..., M, CU 172 includes CSI resource configurations 2, ..., M in... Switching between request and response In the message.

[0137] In some implementations, CU 172 or S-BS 104A obtains LTM SSB configurations 2, ..., M for cells 2, ..., M, respectively, as described for LTM SSB configuration 1. When CU 172 obtains LTM SSB configurations 2, ..., M, CU 172... Switching between request and response The message includes LTM SSB configuration 2, ..., M. In some implementations, CU 172 or S-BS104A obtains PCI 2, ..., M for cells 2, ..., M respectively, as described for PCI 1. When CU 172 obtains PCI 2, ..., M, CU 172... Switching between request and response The message includes PCI 2, ..., M.

[0138] In some implementations, CU 172 includes the following list. Switching between request and response The message contains: {Cell ID 1, LTM ID 1 (if obtained or optional), LTM candidate configuration 1, CSI resource configuration 1 (if obtained or optional), TCI status configuration 1 (if obtained or optional), early synchronization information 1 (if obtained or optional), LTM SSB configuration 1 (if obtained or optional), PCI 1 (if obtained or optional)}, ..., {Cell ID M, LTM ID M (if obtained or optional), LTM candidate configuration M, CSI resource configuration M (if obtained or optional), TCI status configuration M (if obtained or optional), early synchronization information M (if obtained or optional), LTM SSB configuration M (if obtained or optional), PCI M (if obtained or optional)}.

[0139] In some implementations, CU 172 obtains PDCCH command information 2, ..., M for cells 2, ..., M respectively, as described for PDCCH command information 1. In one implementation, CU 172 in Switching between request and response The message includes PDCCH command information 2, ..., M. In another implementation, CU 172 includes PDCCH command information 2, ..., M in the early synchronization information 2, ..., M respectively. S-BS 104A can obtain the information from the early synchronization information 2, ..., M or from... Switching requests should answer The message contains RACH configuration 2, TCI status configuration 2 and / or PDCCH command information 2, ..., RACH configuration M, TCI status configuration M and / or PDCCH command information M.

[0140] In some implementations, the S-BS 104A may perform LTM configuration delivery procedures 2, ..., M with the UE 102 to send the following lists to the UE 102 respectively: {LTM ID 2, LTM candidate configuration 2, CSI resource configuration 2 (if obtained), TCI state configuration 2 (if obtained), RACH configuration 2 (if obtained), LTM SSB configuration 2 (if obtained), PCI 2 (if obtained)}, ..., {LTM ID M, LTM candidate configuration M, CSI resource configuration M, TCI state configuration M (if obtained), RACH configuration M (if obtained), LTM SSB configuration M (if obtained), PCI M (if obtained)}. Each of the LTM configuration delivery procedures 2, ..., M is similar to procedures 394, 494, and / or 594. In other implementations, the S-BS 104A includes the list in the first RRC reconfiguration message.

[0141] In some implementations, S-BS 104A can Switching requests The message includes measurement results 1, ..., N for cells 1, ..., N. S-BS 104A receives the measurement results from UE 102. C-BS 106A can select or determine cells 1, ..., M based on measurement results 1, ..., N. In other implementations, C-BS 106A can select or determine cells 1, ..., M based on one or more other factors (e.g., the capacity or load of cells 1, ..., N and / or the maximum number of LTM candidate cells). In one implementation, the maximum number is included... Switching requests The message states that, in another implementation, the maximum quantity is the predetermined quantity.

[0142] Next reference Figure 6A In scenario 600A, base station 104B operates as the MN, base station 106A operates as a candidate SN (C-SN), and base station 104A operates as a serving or source SN (S-SN). C-SN 106A includes CU 172 and DU 174. MN104B may include CU and DU (…). Figure 6A (not shown in the image), similar to Figure 3 BS 104A in S-SN 104A. S-SN 104A may include CU and DU ( Figure 6A(Not shown in the image), similar to C-SN 106A. Scene 600A is similar to Scene 500, except that Scene 600A is an SN scene, while Scene 500 is an MN scene.

[0143] Initially, UE 102 communicates with MN 104B and S-SN 104A under DC 602. In some implementations, UE 102 is configured to communicate with the DU of S-SN 104A on cell 124A using a serving DU, and to communicate with the CU of S-SN 104A via the DU of S-SN 104A using a serving CU, similar to event 302. In some implementations, UE 102 may transmit 602 UL PDUs and / or DL ​​PDUs with MN 104B and / or S-SN 104A via radio bearers under DC, which may include SRBs and / or DRBs. MN 104B and / or S-SN 104A may be configured to communicate with the radio bearers of UE 102. UE 102 transmits 602 UL PDUs and / or DL ​​PDUs with S-SN 104A on the SCG (i.e., SCG radio resources) configured for communication with UE 102 under DC. UE 102 also transmits UL PDUs and / or DL ​​PDUs with MN 104B on the MCG (i.e., MCG radio resources) according to the MN configuration (i.e., MCG configuration) under DC. In some implementations, the serving DU configuration is an SN configuration (i.e., SCG configuration). In the MN configuration, MN 104B configures an MCG that includes at least one serving cell (e.g., cell 124B and / or other cells) operated by MN 104B. In the serving DU configuration, S-SN 104A configures an SCG that includes at least one serving cell (e.g., cell 124A and / or other cells) operated by S-SN 104A. In some implementations, the MN configuration includes multiple configuration parameters, and UE 102 receives these parameters from MN 104B in one or more RRC messages. For example, regarding... Figure 3 The service DU configuration includes multiple configuration parameters. In some implementations, UE 102 receives these configuration parameters from S-SN 104A in one or more RRC messages, for example, via MN 104B and / or on an SRB (e.g., SRB3) configured to exchange RRC messages between UE 102 and S-SN 104A in MN 104B or S-SN 104A.

[0144] When communicating with UE 102 under the same DC as MN 104B and S-SN 104A, S-SN 104A can perform a CU-in-LTM configuration procedure 696 with UE 102, similar to procedures 396 and / or 496. When communicating with UE 102 under the same DC as MN 104B and S-SN 104A, S-SN 104A can perform a CU-in-LTM procedure 680 with UE 102, similar to procedures 380 and / or 480. In procedure 696 or 680, similar to procedures 394 or 494, the CU of S-SN 104A can send one or more RRC reconfiguration messages to UE 102 via SRB3, each RRC reconfiguration message including one or more LTM candidate configurations. Alternatively, the CU of S-SN 104A may send one or more RRC reconfiguration messages to UE 102 via MN 104B, each RRC reconfiguration message including one or more LTM candidate configurations. In response to each RRC reconfiguration message, UE 102 sends an RRC reconfiguration complete message to S-SN 104A via MN 104B.

[0145] When communicating under DC with MN 104B and S-SN 104A, UE 102 can, for example, send at least one measurement report (604A) to S-SN 104A directly via SRB3, similar to events 304 / 306, 404 / 406, and 504. Alternatively, UE 102 can send the measurement report to MN 104B. MN 104B generates at least one SN message including the measurement report and sends the SN message to CU 172. In one implementation, the SN message includes... RRC transmission Messages and / or SN Modification Request The S-SN104A (e.g., the CU of the S-SN104A) generates a measurement configuration to configure the UE 102 to send measurement reports, and sends measurement reports to the UE 102 directly (e.g., via the S-DU of the S-SN104A) or via the MN 104B.

[0146] After receiving one or more measurement reports from UE 102 (e.g., in response to receiving one or more measurement reports from UE 102), S-SN 104A (e.g., the CU of S-SN 104A) determines to prepare a first cell (e.g., cell 126A) as an LTM candidate cell for UE 102. In response to the determination, S-SN 104A generates an SN request message (first SN request message) that includes a first cell ID (e.g., cell ID 1) of the first cell (e.g., cell 1) and / or indicates a target SN ID for C-SN 106A. In some implementations, the SN request message includes an LTM indicator indicating that the SN request message pertains to LTM for the first cell ID. S-SN 104A sends a 603 SN request message to MN 104B. Upon receiving the SN request message (e.g., in response to receiving the SN request message), MN 104B sends SN request message 605, including the first cell ID (first SN request message), to CU 172 to request the preparation of the first cell as an LTM candidate cell for UE 102. In response to the SN request message, CU 172 and DU 174 perform LTM preparation procedure 690 to prepare the first cell as an LTM candidate cell for UE 102, similar to procedures 390, 490, or 590. In procedure 690, CU 172 sends a first CU-DU message including the first cell ID to DU 174 to request the preparation of the first cell, similar to event 308. In response, CU 172 can receive a first DU-CU message including LTM DU configuration 1 from DU 174, similar to event 310. CU 172 generates a first LTM candidate configuration (LTM candidate configuration 1). In response to the SN request message, CU 172 sends an SN request response message (e.g., a first SN request response message) containing the first LTM candidate configuration to MN 104B (607). In some implementations, CU 172 includes the first cell ID in the SN request response message to indicate that the first LTM candidate configuration is provided for or associated with the first cell (ID). MN 104B sends an SN confirmation message (e.g., a first SN confirmation message) containing the first LTM candidate configuration to S-SN 104A (609A). In some implementations, MN 104B includes the first cell ID in the SN confirmation message to indicate that the first LTM candidate configuration is provided for or associated with the first cell (ID).

[0147] Events 603, 605, 690, 607, and 609A are in Figure 6A The process is collectively referred to as the SN-initiated SN-to-SN LTM preparation process 698A.

[0148] In some implementations, the SN requirement message and the SN acknowledgment message are respectively SN Change Requirements Messages and SN change confirmed recognize Message. In other implementations, the SN requirement message and the SN acknowledgment message are respectively SN Modification Requirements Messages and SN modification confirmed recognize Messages. In some implementations, the SN request message and the SN request response message are respectively... SN Add Request Messages and SN Add Add request and response Messages. In other implementations, the SN request message and the SN request response message are respectively SN Modification Request Messages and SN Modification Request Response information.

[0149] In some implementations, the SN request message includes the DU ID of the S-DU of S-SN 104A. In this case, MN 104B may include the DU ID in the SN request message, and CU 172 may include the DU ID in the first CU to DU message. In other implementations, the SN request message includes the first BS ID of S-SN 104A. In some implementations, MN 104B may include the first BS ID in the SN request message. When the first BS ID is received, CU 172 may include the first BS ID in the first CU to DU message. In some implementations, MN 104B may include its second BS ID in the SN request message. When the second BS ID is received, CU 172 may include the second BS ID in the first CU to DU message. In some implementations, the first BS ID and the second BS ID are gNB IDs.

[0150] CU 172 may or may not request the LTM reference DU configuration in procedure 690, as for... Figure 3 , Figure 4 and Figure 5 As described above. In process 690, DU 174 may or may not send the LTM reference DU configuration to CU 172, as for... Figure 3 , Figure 4 and Figure 5 As described above. In some implementations, the S-SN 104A (e.g., the CU of the S-SN 104A) can obtain an LTM reference configuration, such as for... Figure 3 and Figure 4 As described above. In other implementations, S-SN 104A can be from MN 106B during another SN LTM preparation process as described above and below. Figure 6A(Not shown) Receives an LTM reference configuration. If S-SN 104A obtains the LTM reference configuration, S-SN 104A may include the LTM reference configuration (the LTM reference configuration generated by S-SN) in the SN request message. Subsequently, MN 104B includes the LTM reference configuration in the SN request message. Alternatively, S-SN 104A determines whether to request or cause C-SN 106A to provide a complete LTM candidate configuration, such that S-SN 104A does not send the LTM reference configuration to C-SN 106A. If S-SN 104A does not obtain the LTM reference configuration, S-SN 104A does not include the LTM reference configuration in the SN request message. If the SN request message includes the LTM reference configuration, MN 104B includes the LTM reference configuration in the SN request message. Otherwise, if the SN request message does not include the LTM reference configuration, MN 104B may not include the LTM reference configuration in the SN request message.

[0151] If the SN request message includes the LTM reference configuration as described above, then CU 172 may include the LTM reference configuration in the first CU to DU message. Alternatively, CU 172 may extract the LTM reference DU configuration from the LTM reference configuration and include the LTM reference DU configuration in the first CU to DU message. Otherwise, if the SN request message does not include the LTM reference configuration, then CU 172 may or may not receive the LTM reference DU configuration from DU 174, as shown in the figure for... Figure 3 As described above. If CU 172 receives an LTM reference DU configuration (e.g., in the first DU to CU message), then CU 172 generates an LTM reference configuration that includes the LTM reference DU configuration (the LTM reference configuration generated by the C-SN). CU 172 may include an LTM reference CU configuration (the LTM reference CU configuration generated by the candidate CU (C-CU)). Otherwise, if CU 172 does not receive an LTM reference DU configuration from DU 174, as for... Figure 3 If the above is not true, then CU172 does not generate an LTM reference configuration. Instead, CU172 generates an LTM reference configuration (C-SN generated LTM reference configuration) that only includes the LTM reference CU configuration generated by C-CU. In the case where CU172 generates an LTM reference configuration (C-SN generated LTM reference configuration), CU172 includes the C-SN generated LTM reference configuration in the SN request response message.

[0152] In some implementations, if LTM DU configuration 1 is a complete configuration, CU 172 generates LTM candidate configuration 1 as a complete configuration. CU 172 may include a complete configuration indication (e.g., the BS-to-BS interface protocol field / IE) in the SN request response message to indicate that LTM candidate configuration 1 is a complete configuration. In some implementations, the BS-to-BS interface protocol is the Xn application protocol defined in 3GPP specification 38.423. In some implementations, the complete configuration indication is a new field / IE (e.g., LTM-specific) to avoid impacting non-LTM configurations. In other implementations, the complete configuration indication is an existing field / IE defined in 3GPP specification 38.423. Otherwise, if LTM DU configuration 1 is an incremental configuration, CU 172 generates LTM candidate configuration 1 as an incremental configuration. CU 172 may exclude the complete configuration indication from the SN request response message to indicate that LTM candidate configuration 1 is an incremental configuration. Alternatively, CU 172 may include an incremental configuration indication (e.g., the BS-to-BS interface protocol field / IE) in the SN request response message to indicate that LTM candidate configuration 1 is an incremental configuration. In some implementations, the BS-to-BS interface protocol is the Xn application protocol defined in 3GPP specification 38.423. In some implementations, the incremental configuration indication is a new field / IE (e.g., LTM-specific) to avoid impacting non-LTM configurations. In other implementations, the incremental configuration indication is an existing field / IE defined in 3GPP specification 38.423. In some implementations, the BS-to-BS interface protocol field / IE has two values ​​(i.e., a first value and a second value). The BS-to-BS interface protocol field / IE set to the first value is a full configuration indication, and the BS-to-BS interface protocol field / IE set to the second value is an incremental configuration indication.

[0153] In some implementations, the S-SN 104A is pre-configured with a CSI resource configuration (e.g., (LTM) CSI resource configuration 1) and / or an LTM SSB configuration (LTM SSB configuration 1) for the first cell. In yet another implementation, the CU 172 receives the CSI resource configuration and / or LTM SSB configuration from the OAM (Operation, Administration, and Maintenance) node. In yet another implementation, the S-SN 104A receives the CSI resource configuration and / or LTM SSB configuration from the CU 172. For example, the CU 172 includes the CSI resource configuration and / or LTM SSB configuration in the SN request response message. In this case, the MN 104B can include the CSI resource configuration and / or LTM SSB configuration in the SN confirmation message. In some implementations, the CU 172 includes the PCI of the first cell in the SN request response message. In this case, the MN 104B can include the PCI of the first cell in the SN confirmation message. To prepare the first cell as a candidate LTM cell for UE 102, the CU and S-DU of S-SN 104A perform the LTMCSI report configuration and / or LTM ID configuration procedures. Figure 6A (Not shown in the diagram), similar to procedures 392 or 492. During the LTM CSI report configuration and / or LTM ID configuration process, the CU of S-SN 104A sends the CSI resource configuration and / or LTM SSB configuration to the S-DU of S-SN 104A. In response, the CU of S-SN 104A receives one or more CSI report configurations for UE 102 from the S-DU of S-SN 104A. In some implementations, S-SN 104A receives a second service DU configuration including the CSI report configuration.

[0154] In some implementations, CU 172 receives early synchronization information and / or PDCCH command information for the first cell from DU 174, such as for... Figure 5 As described above. In some implementations, the early synchronization information includes RACH configuration (e.g., RACH configuration 1) and / or at least one TCI state configuration (e.g., TCI state configuration 1). CU 172 includes the early synchronization information and / or PDCCH command information in the SN request response message. MN 104B includes the early synchronization information and / or PDCCH command information in the SN acknowledgment message.

[0155] In some implementations, CU 172 assigns an LTM ID (e.g., LTMID 1) to identify the first LTM candidate configuration and includes the LTM ID and / or its associated (or mapped) cell ID in the SN request response message. MN 104 includes the LTM ID and / or its associated (or mapped) cell ID in the SN confirmation message. In other implementations, S-SN 104A assigns an LTM ID (e.g., LTM ID1) to identify the first LTM candidate configuration. In yet another implementation, MN 104B assigns an LTM ID (e.g., LTM ID1) to identify the first LTM candidate configuration. In such cases, MN 104B may include the LTM ID in the SN confirmation message. After receiving or assigning the LTM ID, the CU of S-SN 104A sends the LTM ID and the first cell ID to the S-DU during the LTM ID configuration process, similar to procedures 390, 392, or 492.

[0156] Upon receiving the SN confirmation message (e.g., in response to receiving the SN confirmation message), S-SN 104A (e.g., the CU of S-SN 104A) performs LTM configuration delivery procedure 694 with UE 102 to send the LTM ID and LTM candidate configuration to UE 102. In some implementations, S-SN 104A sends {LTM ID, LTM candidate configuration} as a tuple in the first RRC reconfiguration message in procedure 694. Depending on the implementation, S-SN 104A may include the LTM reference configuration, CSI report configuration, CSI resource configuration, RACH configuration, TCI state configuration, LTM SSB configuration, and / or the PCI of the first cell for UE 102 in the first RRC reconfiguration message and / or other RRC reconfiguration messages sent to UE 102, such as for the LTM reference configuration, CSI report configuration, CSI resource configuration, RACH configuration, TCI state configuration, LTM SSB configuration, and / or the PCI of the first cell for UE 102. Figure 3 and Figure 4The S-SN 104A includes the LTM ID in the first RRC reconfiguration message or other RRC reconfiguration messages to indicate that the CSI resource configuration, RACH configuration, TCI state configuration, LTM SSB configuration, and / or the PCI of the first cell are associated with the first cell. For example, the S-SN 104A includes the CSI resource configuration, RACH configuration, TCI state configuration, LTM SSB configuration, and / or the PCI of cell 1 in a tuple. In another example, the S-SN 104A includes {LTM ID 1, CSI resource configuration, RACH configuration, TCI state configuration, LTM SSB configuration, and / or the PCI of cell 1} as a tuple in other RRC reconfiguration messages. In response to each RRC reconfiguration message in the other RRC reconfiguration messages, the UE 102 sends an RRC reconfiguration complete message to the CU 172 via the S-DU 174A.

[0157] In some implementations, if the SN request message includes a full configuration indication indicating that LTM candidate configuration 1 is a full configuration, then S-SN 104A includes the full configuration indication (e.g., the RRC field / IE) in the first RRC reconfiguration message to indicate that LTM candidate configuration 1 is a full configuration. Otherwise, if the SN request message does not include a full configuration indication, or includes an incremental configuration indication indicating that LTM candidate configuration 1 is an incremental configuration, then S-SN 104A excludes or does not include the full configuration indication (e.g., the RRC field / IE) from the first RRC reconfiguration message to indicate that LTM candidate configuration 1 is an incremental configuration.

[0158] If the SN confirmation message includes PDCCH command information (PDCCH command information 1), then S-SN 104A can send a 650A PDCCH command to UE 102 based on the PDCCH command information. If S-SN 104A is a distributed base station, then the CU of S-SN 104A can send PDCCH command information to the S-DU of S-SN 104A, and the S-DU can send a 650A PDCCH command to UE 102. For example, S-SN 104A or its S-DU sends a 650A PDCCH command including PDCCH command information to UE 102. In some implementations, S-SN 104A or its S-DU can determine whether to send the PDCCH command based on (e.g., in response to) measurement report 624A. In some implementations, the S-SN 104A or S-DU can determine the SSB index, and / or CSI resource configuration, CSI report configuration, and / or LTM SSB configuration included in the PDCCH command based on the L1 measurement report 624A. In some implementations, the S-DU or S-SN 104A includes LTM ID 1 in the PDCCH command to indicate the first cell. UE 102 uses RACH configuration and / or PDCCH command information to send a 652 RA preamble to DU 174 on the first cell. The S-DU or S-SN 104A derives the TA value based on the RA preamble. DU 174 sends a 656 RA preamble including the TA value to CU 172. DU-CU TA Information Transmission Message. CU 172 sends 657 including the TA value to MN 104B (e.g., the CU of MN 104B). CU-CU TA Information Transmission Message. MN104B sends 658 including the TA value to S-SN 104A. CU-CU TA Information Transmission In some implementations, DU 174 includes cell ID 1, RA preamble index, RA-RNTI, and / or the DU ID of the S-DU of S-SN 104A in message 656. DU 174 may additionally include the first BS ID and / or the second BS ID in message 656. In some implementations, CU 172 includes cell ID 1, RA preamble index, RA-RNTI, and / or the DU ID of the S-DU in message 657. In some implementations, CU 172 may additionally include the first BS ID and / or the second BS ID in message 657. MN 104B then includes cell ID 1, RA preamble index, RA-RNTI, and / or the DU ID of the S-DU in message 658. In some implementations, MN 104B may additionally include the first BS ID and / or the second BS ID in message 658.

[0159] In some implementations, CU 172 determines the address (e.g., IP address) of MN 104B or the CU of MN 104B based on the second BS ID. Therefore, CU 172 sends message 657 to MN 104B according to the address. In some implementations, MN 104B determines the address (e.g., IP address) of S-SN 104A or the CU of S-SN 104A based on the first BS ID. In other implementations, MN 104B determines the address (e.g., IP address) of S-SN 104A or the CU of S-SN 104A based on the DU ID of S-DU of S-SN 104A. Using these implementations, MN 104B sends message 658 to S-SN 104A or the CU of S-SN 104A according to the address. CU-CU TA Information Transmission information.

[0160] In response to, for example, determining a command for UE 102 to perform an LTM cell handover to a first cell based on L1 measurement reports 624A and / or 654A, S-DU or S-SN 104A sends an LTM cell handover command 626A, including LTM ID 1, to UE 102. In response to the LTM cell handover command, UE 102 may cease communication on the serving cell. In response to the LTM cell handover command, UE 102 accesses the first cell 632 and sends an RRC reconfiguration complete message 636A to DU 174. DU 174 then sends a DU-CU message 638, including the RRC reconfiguration complete message, to CU 172. In some alternative implementations, UE 102 sends the RRC reconfiguration complete message to C-SN 106A via MN 104B instead of via DU 174. Upon receiving a DU to CU message 638 or an RRC reconfiguration complete message, C-SN 106A communicates 640 with UE 102, which is under the DC of MN 104B and C-SN 106A, according to a first LTM candidate configuration and / or LTM reference configuration. In some implementations, UE 102 includes LTM ID 1 in the RRC reconfiguration complete message 636A to indicate that UE 102 applies the first LTM candidate configuration. Based on LTM ID 1, CU 172 identifies the first LTM candidate configuration and / or LTM reference configuration. In other implementations, CU 172 is based on the configuration included in... Connection successful The first cell ID in message 634 is used to identify the first LTM candidate configuration and / or LTM reference configuration. In this implementation, CU 172 maintains or stores the association information between the first cell ID and the first LTM candidate configuration and / or LTM reference configuration. When CU 172... Connection successfulWhen the first cell ID is received in the message, CU 172 identifies the first LTM candidate configuration and / or LTM reference configuration based on the first cell ID and associated information.

[0161] In some implementations, if the S-DU or S-SN 104A receives a TA value, as described above, the S-DU or S-SN 104A may include the TA value in the LTM cell handover command. In some implementations, the S-DU or S-SN 104A includes the first TCI state ID in the LTM cell handover command. The first TCI state ID indicates the first TCI state configuration in the TCI state configuration.

[0162] In response to the confirmation command UE 102 to perform LTM cell handover or to send the 626A LTM ​​cell handover command, the S-DU of S-SN 104A sends a message to the CU of S-SN 104A. DU-CU cell handover notification The message instructs UE 102 to perform an LTM cell handover to the first cell. In response to receiving... DU-CU cell handover notification Message: The CU of S-SN 104A sends a 627A signal to MN 104B. CU-CU cell handover notification The message instructs UE 102 to perform or be performing an LTM cell handover to the first cell. In response, MN 104B sends 628 to CU 172. CU-CU cell handover notification The message instructs UE 102 to perform or be performing an LTM cell handover to the first cell. In response, CU 172 sends 630 to DU 174. CU-DU Cell Handover Notification The message indicates that UE 102 is performing or in the process of an LTM cell handover to the first cell. In some implementations, S-SN104A includes the first TCI state ID. CU-CU cell handover notification In message 627A. Under these circumstances, MN 104B is... CU-CU cell handover notification Message 628 includes the first TCI status ID. CU 172 then includes the first TCI status ID in... CU-DU Cell Handover Notification In the message, UE 102 and DU 174 identify the first TCI state configuration in the TCI state configuration based on the first TCI state ID, and apply the first TCI state configuration to communicate UL transmissions and / or DL ​​transmissions in events 632, 636A and / or 640.

[0163] In some implementations, after determining whether to instruct UE 102 to perform an LTM cell handover or to send a 626A LTM ​​cell handover command (e.g., in response to determining whether to instruct UE 102 to perform an LTM cell handover or to send a 626A LTM ​​cell handover command), S-SN 104A sends one or more 631 commands to MN 104B. Early state transferEach early state delivery message includes the DL COUNT value of the DRB or the DISCARD DL COUNT value of the data on which UE 102 and S-SN 104A communicate with each other. MN 104B sends one or more of these messages to CU 172. Early state transfer Each early status delivery message includes the DL COUNT value or DISCARD DL COUNT value of the DRB for UE 102 and S-SN 104A to transmit 602 data to each other.

[0164] In some implementations, when receiving 634 to Connection successful After receiving either a 638 message (DU to CU) or an RRC reconfiguration complete message, CU 172 sends a 639 LTM success message to MN 104B (e.g., the CU of MN 104B) to indicate that the LTM cell handover was successfully completed. In some implementations, the LTM success message is... SN Modification Requirements The message is either a BS-to-BS access success message. In some implementations, CU 172 includes the first cell ID in the LTM success message. In other implementations, CU 172 does not send a BS-to-BS message to MN 104B (e.g., the CU of MN 104B) to indicate successful LTM cell handover. In some implementations, after receiving the LTM success message or receiving the RRC reconfiguration completion message from UE 102 (e.g., in response to receiving the LTM success message or receiving the RRC reconfiguration completion message from UE 102), MN 104B may send an SN message (e.g., ...) to S-SN 104A. Figure 6C (As shown in event 645). The SN message can indicate that the LTM cell handover has been successfully completed, instruct S-SN 104A to suspend communication with UE 102, or instruct S-SN 104A to release the UE context and resources configured for UE 102. MN 104B can include the first cell ID in the SN message. In some implementations, the SN message is... SN Modification Request information, SN release request Messages, SN access success messages, etc.

[0165] In some implementations, the UE 102 determines the command to perform LTM cell handover, sends the 626A LTM ​​cell handover command, and receives data from the S-DU. DU-CU cell handover notification After receiving a message or an SN message (e.g., in response to a confirmation command UE102 performing an LTM cell handover, sending a 626A LTM ​​cell handover command, receiving a DU-CU cell handover notification message from an S-DU, or receiving an SN message), S-SN 104A (e.g., the CU of S-SN 104A) sends a 641 message to MN 104B. SN status transmission The message, the SN status transmission message, includes the DL COUNT value and / or UL COUNT value of the DRB used by UE 102 and S-BS 104A to transmit 602 data to each other. Upon receiving SN status transmission Following message 641 (e.g., in response to receiving SN status transmission message 641), MN 104B sends message 642 to CU 172, including the DL COUNT value and / or the UL COUNT value. SN status transmission information.

[0166] In some implementations, S-SN 104A (e.g., the CU of S-SN 104A) may prepare additional cells (i.e., cells 2, ..., N) as LTM candidate cells for UE 102 before or after sending the LTM cell handover command, or during or after procedure 698A, as described above. N is an integer greater than 1. Cells 2, ..., N may be operated by the C-SNs. For example, S-SN 104A and MN 104B perform additional inter-SN LTM preparation procedures 2, ..., N to prepare cells 2, ..., N respectively. Each of the inter-SN LTM preparation procedures 2, ..., N is similar to procedure 698A. In the inter-SN LTM preparation procedures 2, ..., N, S-SN 104A receives LTM candidate configurations 2, ..., N for LTM respectively. As described above, MN 104B, S-SN 104A, or C-SN assigns LTMID 2, ..., N to identify LTM candidate configurations 2, ..., N, respectively. S-SN 104A can obtain CSI resource configurations 2, ..., N for cells 2, ..., N, as described for CSI resource configuration 1. S-SN 104A can obtain CSI report configurations 2, ..., N or cells 2, ..., N, as described for CSI report configuration 1. S-SN 104A can obtain RACH configurations 2, ..., N for cells 2, ..., N, as described for RACH configuration 1. S-SN 104A can obtain TCI status configurations 2, ..., N for cells 2, ..., N, as described for TCI status configuration 1. S-SN 104A can obtain LTM SSB configurations 2, ..., N for cells 2, ..., N, as described for LTM SSB configuration 1. In some implementations, S-SN 104A can perform LTM configuration delivery procedures 2, ..., N with UE 102 to send {LTM ID 2, LTM candidate configuration 2, CSI resource configuration 2 (if obtained), TCI state configuration 2 (if obtained), RACH configuration 2 (if obtained), LTM SSB configuration 2 (if obtained)}, ..., {LTM ID N, LTM candidate configuration N, CSI resource configuration N, TCI state configuration N (if obtained), RACH configuration N (if obtained), LTM SSB configuration N (if obtained)} to UE 102 respectively. Each of LTM configuration delivery procedures 2, ..., N is similar to procedures 394, 494, and / or 594. In other implementations, S-SN 104A includes the tuples in the first RRC reconfiguration message.

[0167] In some implementations, the SN request message and SN confirmation message in each of the SN-to-SN LTM preparation processes 2, ..., N are respectively the SN modification request message and the SN modification confirmation message. In other implementations, the SN request message and SN confirmation message in each of the SN-to-SN LTM preparation processes 2, ..., N are respectively the SN change request message and the SN change confirmation message. In some implementations, the SN request message and SN request response message in each of the SN-to-SN LTM preparation processes 2, ..., N are respectively... SN Add Request Messages and SN Add Request and Response Messages. In other implementations, the SN request message and SN request response message in each of the SN-to-SN LTM preparation processes 2, ..., N are respectively SN Modification Request Messages and Please modify SN Request for response In some implementations, the information provided in the SN confirmation message (e.g., LTM candidate configuration, LTM reference configuration, first cell ID, or LTM ID) is instead provided in the SN modification request message from MN 104B to S-SN 104A (i.e., similar to event 609B, which will be described in scenario 600B).

[0168] In other implementations, S-SN 104A and CU 172 perform process 698A to prepare cells 1 and 2, ..., N (one or more of them) as LTM candidate cells for UE 102. Cells 2, ..., N are identified by cell IDs 2, ..., N, respectively, and are operated by DU 174 and / or other DUs of C-SN 106A. In such an implementation, S-SN 104A includes cell IDs 2, ..., N in the SN request message 603 for LTM, and MN 104B includes cell IDs 2, ..., N in the SN request message, as described above for cell ID 1. In some implementations, upon receiving the SN request message, CU 172 determines or selects cells 1, ..., M from cells 1, ..., N as LTM candidate cells. M is a positive integer and M ≤ N. In other implementations, CU 172 prepares cells 1, ..., N for LTM as requested in the SN request message. CU 172 and DU 172 perform LTM preparation procedures 2, ..., M to prepare cells 2, ..., M as LTM candidate cells for UE 102, respectively. LTM preparation procedures 2, ..., M are similar to the procedure 690 performed by CU 172 and DU 174 to prepare cell 1. As a result of LTM preparation procedures 2, ..., M, CU 172 obtains LTM candidate configurations 2, ..., M for cells 2, ..., M, respectively, similar to obtaining LTM candidate configuration 1. C-SN 106A can generate LTM candidate configurations 2, ..., M as a complete configuration, or generate incremental configurations based on the LTM reference configuration, as described for LTM candidate configuration 1. CU 172 includes LTM candidate configurations 2, ..., M in the SN request response message. In some implementations, CU 172, MN 104B, or S-SN 104A assigns LTM IDs 2, ..., M to identify LTM preparation processes 2, ..., M, respectively, as described for LTM ID 1 and LTM candidate configuration 1. When CU 172 assigns LTM IDs 1, ..., M, CU 172 includes LTM IDs 1, ..., M and LTM candidate configurations 1, ..., M in the SN request response message, respectively, as described for LTM ID 1 and LTM candidate configuration 1.

[0169] In some implementations, CU 172 obtains early synchronization information 2, ..., M for cells 2, ..., M respectively, as described for early synchronization information 1. CU 172 includes the early synchronization information 2, ..., M in the SN request response message. In some implementations, CU 172 or S-SN 104A obtains CSI resource configurations 2, ..., M for cells 2, ..., M respectively, as described for CSI resource configuration 1. When CU 172 obtains CSI resource configurations 2, ..., M, CU 172 includes the CSI resource configurations 2, ..., M in the SN request response message.

[0170] In some implementations, CU 172 or S-SN 104A obtains LTM SSB configurations 2, ..., M for cells 2, ..., M, as described for LTM SSB configuration 1. When CU 172 obtains LTM SSB configurations 2, ..., M, CU 172 includes LTM SSB configurations 2, ..., M in the SN request response message. In some implementations, CU 172 or S-SN 104A obtains PCI 2, ..., M for cells 2, ..., M, as described for PCI 1. When CU 172 obtains PCI 2, ..., M, CU 172 includes PCI 2, ..., M in the SN request response message.

[0171] In some implementations, CU 172 includes the following list in the SN request response message: {Cell ID 1, LTMID 1 (if obtained or optional), LTM candidate configuration 1, CSI resource configuration 1 (if obtained or optional), TCI status configuration 1 (if obtained or optional), Early synchronization information 1 (if obtained or optional), LTM SSB configuration 1 (if obtained or optional), PCI 1 (if obtained or optional)}, ..., {Cell ID M, LTM ID M (if obtained or optional), LTM candidate configuration M, CSI resource configuration M (if obtained or optional), TCI status configuration M (if obtained or optional), Early synchronization information M (if obtained or optional), LTM SSB configuration M (if obtained or optional), PCI M (if obtained or optional)}. MN 104B includes the list or a portion of the list in the SN confirmation message.

[0172] In some implementations, CU 172 obtains PDCCH command information 2, ..., M for cells 2, ..., M, as described for PDCCH command information 1. In one implementation, CU 172 includes PDCCH command information 2, ..., M in the SN request response message. In another implementation, CU 172 includes PDCCH command information 2, ..., M in the early synchronization information 2, ..., M, respectively. MN 104B may include PDCCH command information 2, ..., M in the SN acknowledgment message, as described for PDCCH command information 1. S-SN 104A may obtain RACH configuration 2, TCI status configuration 2, and / or PDCCH command information 2, ..., RACH configuration M, TCI status configuration M, and / or PDCCH command information M from the early synchronization information 2, ..., M or from the SN acknowledgment message.

[0173] In some implementations, S-SN 104A can perform LTM configuration delivery procedures 2, ..., M with UE 102 to send tuples {LTM ID 2, LTM candidate configuration 2, CSI resource configuration 2 (if obtained), TCI state configuration 2 (if obtained), RACH configuration 2 (if obtained), LTM SSB configuration 2 (if obtained), PCI 2 (if obtained)}, ..., {LTM ID M, LTM candidate configuration M, CSI resource configuration M, TCI state configuration M (if obtained), RACH configuration M (if obtained), LTM SSB configuration M (if obtained), PCI M (if obtained)} to UE 102 respectively. Each of LTM configuration delivery procedures 2, ..., M is similar to procedures 394, 494, and / or 594. In other implementations, S-SN 104A includes the tuples in the first RRC reconfiguration message.

[0174] In some implementations, MN 104B may include the measurement results 1, ..., N for cells 1, ..., N in the SN request message. In some implementations, MN 104B may receive the measurement results from UE 102 and / or from the SN request message from S-SN 104A. C-SN 106A may select or determine cells 1, ..., M based on the measurement results 1, ..., N. In other implementations, C-SN 106A may select or determine cells 1, ..., M based on other factors (e.g., the capacity or load of cells 1, ..., N and / or the maximum number of LTM candidate cells). In one implementation, the maximum number is included in the SN request message. In another implementation, the maximum number is a predetermined number.

[0175] Events 626A, 627A, 628, 630, 631, 632, 633, and 634 are in Figure 6A This is collectively referred to as LTM execution process 699.

[0176] Next reference Figure 6B Scenario 600B is generally similar to Scenario 600A, except that Scenario 600B includes events 604B, 609B, and 611, instead of events 603 and 609A. In Scenario 600B, MN 104B initiates the 698B inter-SN LTM preparation procedure, while in Scenario 600A, S-SN 104A initiates the 698A inter-SN LTM preparation procedure. When communicating with MN 104B and S-SN 104A under DC, UE 102 can send at least one measurement report of 604B to MN 104B, for example via SRB1, similar to events 304 / 306, 404 / 406, and 504. If MN 104B is a distributed base station, then MN 104B includes CU and DU. The CU of MN 104B receives measurement reports from UE 102 via the DU of MN 104B. MN 104B (e.g., CU of MN 104B) generates a measurement configuration to configure UE 102 to send a measurement report, and sends the measurement configuration to UE 102 (e.g., via DU of MN 104B).

[0177] After receiving one or more measurement reports from UE 102 (e.g., in response to receiving one or more measurement reports from UE 102), MN 104B (e.g., the CU of MN 104B) determines to prepare a first cell (e.g., cell 124B) as an LTM candidate for UE 102. In response to this determination, MN 104B generates an SN request message (first SN request message) including the first cell ID (e.g., cell ID 1) of the first cell (e.g., cell 1) and sends a 605 SN request message to C-SN 106A. In response to the SN request message, CU 172 (determines and) performs the LTM preparation procedure 690 with DU 174 and sends a 607 SN request response message to MN 104B, as per the LTM preparation procedure for UE 102. Figure 6A As described above. Upon receiving message 607 (e.g., in response to receiving message 607), MN 104B sends 609B to S-SN 104A, including the first LTM candidate configuration (LTM candidate configuration 1), the LTM reference configuration, and / or the first cell ID. SN Modification RequestThe message is similar to Event 609A. If the SN request response message includes LTM-related configurations for configuring the first cell as an LTM candidate cell, such as RACH configuration, TCI state configuration, CSI resource configuration, LTM SSB configuration, and / or the PCI of the first cell, then MN 104B will include the LTM-related configurations in the message. SN Modification Request In the message. Response to SN Modification Request Message: S-SN 104A sends 611 to MN 104B SN Modification Request Response The message, and together with UE 102, executes LTM configuration delivery procedure 694 to send the first LTM candidate configuration and / or LTM reference configuration to UE 102. Events 605, 690, 607, 609B and 611 in Figure 6B This is collectively referred to as the MN-initiated SN-interval LTM preparation process 698B.

[0178] For example, regarding Figure 6A The SN request response message 607 may include PDCCH command information. If the SN request response message 607 includes PDCCH command information, then MN 104B in SN Modification Request The message includes PDCCH command information. If SN Modification Request If the message includes PDCCH command information, then S-SN 104A can send a 650A PDCCH command to UE 102 based on the PDCCH command information, such as for... Figure 6A As stated. If SN Modification Request If the message includes TCI status configuration, then S-SN 104A can be configured as follows: Figure 6A The description includes the first TCI status ID in the LTM cell handover command.

[0179] In some implementations, MN 104B (e.g., the CU of MN 104B) may perform one or more LTM preparation procedures with CU 172 or other C-SNs to prepare additional cells (i.e., cell 2, ..., N) as LTM candidate cells for UE 102, and each of the LTM preparation procedures is similar to procedure 698B. MN 104B may perform the LTM preparation procedure before or after sending the LTM cell handover command, or during, before or after procedure 698B.

[0180] In other implementations, MN 104B and CU 172 perform process 698B to prepare cell 1 and cell 2, ..., N (one or more of them) as LTM candidate cells for UE 102. N is an integer greater than 1. Cell 2, ..., N are identified by cell ID 2, ..., N respectively, and are operated by DU 174 and / or other DU operations of C-SN 106A. In such an implementation, MN 104B includes cell ID 2, ..., N in SN request message 605, as described above for cell ID 1.

[0181] Next reference Figure 6C Scenario 600C is largely similar to scenarios 600A and 600B, except that it includes events 694C, 636C, and 645 instead of events 694A, 636A, and 638. In scenario 600C, MN 104B, in LTM configuration delivery procedure 694C, sends a second serving DU configuration (including CSI report configuration), LTM ID, first LTM candidate configuration, LTM reference configuration, CSI resource configuration, LTM SSB configuration, RACH configuration, TCI state configuration, and / or the PCI of the first cell to UE 102 in one or more RRC reconfiguration messages to configure the first cell as an LTM candidate cell, similar to procedures 394, 494, or 594. In some implementations, MN 104B generates the RRC reconfiguration message in procedure 694C, while S-SN 104A generates the RRC reconfiguration message in procedure 694A. In some implementations, MN 104B assigns LTM IDs in scenario 600C, while S-SN 104A assigns LTM IDs in scenarios 600A and 600B.

[0182] When UE 102 performs the 699 LTM execution procedure, UE 102 sends a 636C RRC reconfiguration message to MN 104B, similar to event 636A. In some implementations, UE 102 includes the LTM ID in the RRC reconfiguration completion message to indicate that UE 102 applies the first LTM candidate configuration. After receiving the RRC reconfiguration message (e.g., in response to receiving the RRC reconfiguration message), MN 104B may send a 645 SN message to S-SN 104A, as per the example provided. Figure 6A As described above. In some implementations, the MN 104B may include the first cell ID of the first cell in the SN message. The MN 104B may determine the first cell ID based on the LTM ID received in the RRC reconfiguration completion message.

[0183] Next reference Figure 6DScene 600D is largely similar to scenes 600A, 600B, and 600C, except that scene 600D includes events 624D, 650D, 654D, and 626D instead of events 624A, 650A, 654A, and 626A. Events 624D, 650D, 654D, and 626D are similar to events 624A, 650A, 654A, and 626A, respectively, except that MN 104B participates in events 624D, 650D, 654D, and 626D, while S-SN 104A participates in events 624A, 650A, 654A, and 626A.

[0184] In some implementations, MN 104B can generate a CSI report configuration based on the CSI resource configuration, as described for S-SN 104A. The CSI resource configuration is configured in the RS transmitted on the first cell. In procedure 694C, MN 104B sends the CSI report configuration to UE 102. In some implementations, MN 104B is pre-configured with the CSI resource configuration. In other implementations, MN 104B receives the CSI resource configuration from the OAM node. In other implementations, MN 104B receives the CSI resource configuration from CU 172 or S-SN 104A.

[0185] Next, refer to Figures 7A to 15 Several example methods for LTM that can be implemented in RAN nodes (e.g., base stations, DUs, or CUs) or UEs are discussed. For Figures 3 to 6D The description described herein may be applicable Figures 7A to 15 Similar steps are similarly labeled (e.g., 302, 402, 502, 602, 802, etc.) and therefore individual descriptions are omitted.

[0186] Figure 7A This shows that it can be generated by S-SN (e.g., Figures 6A to 6DExample method 700A is implemented using S-SN 104A. Method 700A begins at block 702, where the S-SN communicates with the UE located under the DC of the MN and the S-SN. At block 780, the S-SN may perform at least one in-SN LTM configuration and / or execution procedure (e.g., event 696 or 680) with the UE. At block 760, the S-SN determines a first cell to prepare as an LTM candidate cell for the UE. At block 703, the S-SN sends an SN request message to the MN requesting the preparation of the first cell as an LTM candidate cell for the UE. In some implementations, the SN request message includes a first cell ID of the first cell. At block 709A, the S-SN receives from the MN an SN confirmation message including a first LTM candidate configuration that configures the first cell as an LTM candidate cell for the UE. At block 762, the S-SN obtains a first LTM CSI resource configuration that configures the CSI resources for the first cell. At block 764, the S-SN generates a first LTM CSI report configuration based on the first LTM CSI resource configuration. At block 718, the S-SN sends a first LTM candidate configuration, a first LTM CSI resource configuration, and a first LTM CSI report configuration to the UE. At block 724, the S-SN receives one or more L1 measurement reports from the UE according to the first LTM CSI report configuration. In some implementations, the intra-SN LTM configuration and / or execution process includes an intra-SN DU LTM configuration and / or execution process similar to procedures 396 or 380. In other implementations, the intra-SN LTM configuration and / or execution process includes an intra-SN DU LTM configuration and / or execution process similar to procedures 496 or 480.

[0187] In some implementations, the S-SN receives the first LTM CSI resource configuration from a network node (e.g., OAM). In other implementations, the S-SN pre-configures the first LTM CSI resource configuration in a storage device and obtains it from the storage device. In some implementations, the first LTM CSI report configuration configures CSI reports for the CSI resources configured in the first LTM CSI resource configuration. In some implementations, the CSI resources include one or more reference signals, and / or time and frequency resources for the reference signals. The reference signals may include SSBs and / or CSI-RS.

[0188] In some implementations, the L1 measurement report includes L1 measurement results for the first cell. The L1 measurement report may also include L1 measurement results for the serving cell, wherein the S-SN receives the L1 measurement report. Based on the L1 measurement report, the S-SN determines whether to instruct the UE to perform an LTM cell handover to the first cell. If the S-SN determines to instruct the UE to perform an LTM cell handover to the first cell, the S-SN sends an LTM cell handover command to the UE, thereby instructing the UE to perform an LTM cell handover to the first cell. In response to instructing the UE to perform an LTM cell handover, the S-SN may send a CU to the MN. Cell handover notification This message notifies the S-SN to send an LTM cell handover command to the UE, enabling LTM cell handover to the first cell. In response to the command to the UE to perform the LTM cell handover, the S-SN can send a message to the MN. Early state transfer The early state delivery message includes the DL COUNT value or DISCARD DL COUNT value of the DRB used by the UE and S-SN to transmit data to each other. After sending the LTM cell handover command, the S-SN can receive an LTM success message from the MN, thereby notifying that the LTM cell handover has been successfully completed. In response to the command to the UE to perform the LTM cell handover, or after sending the LTM cell handover command or receiving the LTM success message, the S-SN can send a message to the MN. SN status transmission The message, which transmits the SN status message, includes the UL COUNT value and / or DL ​​COUNT value for the DRB.

[0189] In some implementations, the S-SN generates at least one first RRC message including a first LTM candidate configuration, a first configuration ID identifying the first LTM candidate configuration, a first LTM CSI resource configuration, and a first LTM CSI reporting configuration. In some implementations, the S-SN generates a first LTM configuration including the first LTM candidate configuration, the first configuration ID, and the first LTM CSI resource configuration. In some implementations, the first configuration ID is an LTM candidate ID. In some implementations, the S-SN generates a first service configuration including the first LTM CSI reporting configuration. For example, the first service configuration is a cell group configuration (e.g., CellGroupConfig IE). At block 718, the S-SN sends a first RRC message including the first LTM configuration and the first service configuration to the UE via an MN or SRB (e.g., SRB3). In some implementations, the SN confirmation message (first SN confirmation message) includes a first cell ID indicating that the first LTM candidate configuration is associated with a first cell. In other implementations, the SN confirmation message includes the first cell ID in response to an SN request message (first SN request message) including the first cell ID.

[0190] In some implementations, when or after preparing the first cell for LTM, the S-SN can prepare a second cell of the C-SN (i.e., the first C-SN) as an LTM candidate cell for the UE by sending a second SN request message to the MN, similar to box 703. In some implementations, the second SN request message includes the second cell ID of the second cell. In response, the S-SN receives a second SN confirmation message from the MN, which includes a second LTM candidate configuration for the second cell used for LTM, similar to box 709A. The S-SN obtains a second LTM CSI resource configuration for the CSI resources used for the second cell and generates a second LTM CSI report configuration based on the second LTM CSI resource configuration, similar to boxes 762 and 764, respectively. In some implementations, the S-SN includes the second LTM candidate configuration, a second configuration ID identifying the second LTM candidate configuration, the second LTM CSI resource configuration, and the second LTM CSI report configuration in the first RRC message. The S-SN may include the second LTM CSI report configuration in the first service configuration or the first RRC message. In some implementations, the second configuration ID is the LTM candidate ID.

[0191] In other implementations, the S-SN sends at least one second RRC message to the UE, which includes a second configuration ID, a second LTM candidate configuration, a second LTM CSI resource configuration, and a second LTM CSI report configuration, similar to box 718. In some implementations, the S-SN generates a second LTM configuration, which includes a second LTM candidate configuration, a second configuration ID, and a second LTM CSI resource configuration. In some implementations, the S-SN may include the second LTM CSI report configuration in a second service configuration, and also include the second service configuration in the second RRC message. For example, the second service configuration is a cell group configuration (e.g., CellGroupConfig IE). The S-SN includes the second LTM configuration and the second service configuration in the second RRC message.

[0192] In some implementations, the second SN request message includes the second cell ID to indicate that the second LTM candidate configuration is associated with the second cell. In other implementations, the second SN confirmation message includes the second cell ID in response to a second SN request that includes the second cell ID.

[0193] In some implementations, when or after preparing the first cell for LTM, the S-SN can prepare a third cell of another C-SN (i.e., the second C-SN) as an LTM candidate cell for the UE by sending a third SN request message to the MN, similar to box 703. In some implementations, the third SN request message includes the third cell ID of the third cell. In response, the S-SN receives a third SN confirmation message from the MN, which includes a third LTM candidate configuration for the third cell used for LTM, similar to box 709A. The S-SN obtains a third LTM CSI resource configuration for the CSI resources used for the third cell and generates a third CSI report configuration based on the third LTM CSI resource configuration, similar to boxes 762 and 764, respectively. In some implementations, the S-SN includes the third LTM candidate configuration, a third configuration ID identifying the third LTM candidate configuration, and the third LTM CSI resource configuration in the first LTM configuration, the second LTM configuration, the first RRC message, and / or the second RRC message. The S-SN can include a third LTM CSI report configuration in the first service configuration, the first RRC message, the second service configuration, or the second RRC message. In some implementations, the third configuration ID is an LTM candidate ID.

[0194] In other implementations, the S-SN sends at least one third RRC message to the UE, which includes a third LTM candidate configuration, a third configuration ID, a third LTM CSI resource configuration, and a third LTM CSI report configuration, similar to box 718. In some implementations, the S-SN generates a third LTM configuration, which includes a third LTM candidate configuration, a third configuration ID, and a third LTM CSI resource configuration. In some implementations, the S-SN includes the third LTM CSI report configuration in the third service configuration and also includes the third service configuration in the third RRC message. For example, the third service configuration is a cell group configuration (e.g., CellGroupConfig IE). The S-SN includes both the third LTM configuration and the third service configuration in the third RRC message.

[0195] In some implementations, the third SN request message includes the third cell ID to indicate that the third LTM candidate configuration is associated with a third cell. In other implementations, the third SN confirmation message includes the third cell ID in response to a third SN request that includes the third cell ID.

[0196] When the S-SN prepares the first cell and the second and / or the third cell simultaneously as described above, the S-SN can determine which SN confirmation message responds to which SN request message based on the cell ID in the SN request message and the SN confirmation message. In some implementations, the first RRC message, the second RRC message, and the third RRC message are RRC reconfiguration messages.

[0197] Figure 7B This is a flowchart of an example method 700B, similar to method 700A, except that method 700B includes block 709B instead of blocks 709A and 762. At block 709B, the S-SN receives an SN confirmation message from the MN. This SN confirmation message includes a first LTM candidate configuration and a first LTM CSI resource configuration for the UE. The first LTM candidate configuration configures a first cell for LTM, and the first LTM CSI resource configuration configures CSI resources for LTM. Unlike method 700A, the S-SN receives the LTM CSI resource configuration from the MN.

[0198] Figure 8A This shows that it can be generated by S-SN (e.g., Figures 6A to 6D Example method 800A is similar to method 700A, implemented by the CU of S-SN 104A. Method 800A begins at block 802, where the CU communicates with the UE under the DC of the MN and S-SN, wherein the CU communicates with the UE via S-DU (e.g., event 302). At block 880-1, the CU may perform intra-DU LTM configuration and / or execution procedures with the S-DU and the UE (e.g., events 396 or 380). At block 880-2, the CU may perform inter-DU LTM configuration and / or execution procedures with the C-DU and the UE (e.g., events 496 or 480). The process proceeds to blocks 760, 703, 709A, and 762. At block 812, the CU sends a first CU-DU message to the S-DU including a first LTM CSI resource configuration. At block 718, the CU sends a first LTM candidate configuration, a first LTM CSI resource configuration, and a first LTM CSI report configuration to the UE.

[0199] against Figure 7A The described examples and implementations can be applied to Figure 8AIn some implementations, the CU includes the second configuration ID and the second cell ID in the first CU-DU message. In other implementations, the CU sends a second CU-DU message to the S-DU including the second configuration ID and the second cell ID, similar to events 312, 392, or 492. In some implementations, the CU includes a third configuration ID and a third cell ID in either the first or second CU-DU message. In other implementations, the CU sends a third CU-DU message to the S-DU including the third configuration ID and the third cell ID, similar to events 312, 392, or 492.

[0200] Figure 8B This is a flowchart of example method 800B, which is similar to methods 800A and 700B, except that method 800B includes box 709B instead of boxes 709A and 762.

[0201] Figure 9A It shows that it can be made by MN (e.g., Figures 6A to 6D Example method 900A is implemented by MN (104B). Method 900A begins at block 902, where the MN communicates with the UE under the DC of the MN and the S-SN. At block 980, the MN may perform at least one in-MN LTM configuration and / or execution procedure (e.g., events 396, 380, 496, and / or 480) with the UE. At block 905, the MN sends an SN request message to the C-SN requesting the preparation of a first cell as an LTM candidate cell for the UE. In some implementations, the SN request message includes a first cell ID of the first cell. At block 907A, the MN receives an SN request response message from the C-SN, which includes a first LTM candidate configuration configuring the first cell as an LTM candidate cell for the UE. At block 962, the MN obtains a first LTM CSI resource configuration configuring CSI resources for the first cell. The process can proceed from block 962 to block 964, where the MN generates a first LTM CSI report configuration based on the first LTM CSI resource configuration. The process continues to box 918, where MN sends the first LTM configuration, the first LTM CSI resource configuration, and the first LTM CSI report configuration to the UE. The process continues to box 924, where MN receives one or more L1 measurement reports from the UE according to the first LTM CSI report configuration.

[0202] Alternatively, the process can proceed from box 962 to box 909A, where MN sends an SN message to S-SN, which includes a first LTM candidate configuration and a first LTM CSI resource configuration.

[0203] In some implementations, the intra-MN LTM configuration and / or execution process includes an intra-MN DU LTM configuration and / or execution process similar to process 396 or 380. In other implementations, the intra-MN LTM configuration and / or execution process includes an intra-MN DU LTM configuration and / or execution process similar to process 496 or 480.

[0204] In some implementations, the MN receives a first LTM CSI resource configuration from a network node (e.g., OAM). In other implementations, the MN pre-configures the first LTM CSI resource configuration in a storage device and obtains the first LTM CSI resource configuration from the storage device. In some implementations, a first LTM CSI report configuration configures CSI reports for the CSI resources configured in the first LTM CSI resource configuration. In some implementations, the CSI resources include one or more reference signals, and / or time and frequency resources for the reference signals. The reference signals may include SSBs and / or CSI-RS.

[0205] In some implementations, the L1 measurement report includes L1 measurement results for the first cell. The L1 measurement report may also include L1 measurement results for the serving cell, where the MN receives the L1 measurement report. Based on the L1 measurement report, the MN determines whether to instruct the UE to perform an LTM cell handover to the first cell. If the MN determines to instruct the UE to perform an LTM cell handover to the first cell, the MN sends an LTM cell handover command to the UE, thereby instructing the UE to perform an LTM cell handover to the first cell. In response to instructing the UE to perform an LTM cell handover, the MN may send a CU to the S-SN. Cell handover notification The message notifies the MN to initiate an LTM cell handover command to the UE, enabling LTM cell handover to the first cell. This is followed by sending the CU to the S-SN. Community cut Change notification After the message, MN can receive from S-SN Early state transfer Message, and send to C-SN Early state transfer information. Early state transfer The message may include the DL COUNT value or DISCARD DL COUNT value of the DRB used by the UE and S-SN to transmit data to each other. After sending the LTM cell handover command, the MN can receive an LTM success message from the C-SN, thereby notifying that the LTM cell handover has been successfully completed. In response to the commanding UE to perform an LTM cell handover, or after sending the LTM cell handover command or receiving an LTM success message, the MN can receive the LTM success message from the S-SN. SN status transmission Message, and send to C-SN SN status transmission information. SN status transmissionThe message may include the UL COUNT value and / or DL ​​COUNT value for the DRB.

[0206] In some implementations, the MN generates at least one first RRC message including a first LTM candidate configuration, a first configuration ID identifying the first LTM candidate configuration, a first LTM CSI resource configuration, and a first LTM CSI report configuration. In some implementations of block 964, the MN generates a first LTM configuration including the first LTM candidate configuration, the first configuration ID, and the first LTM CSI resource configuration, and includes the first LTM configuration in the first RRC message. In some implementations, the first configuration ID is an LTM candidate ID. In some implementations, the MN generates a first service configuration including the first LTM CSI report configuration. For example, the first service configuration is a cell group configuration (e.g., CellGroupConfig IE). At block 918, the MN sends a first RRC message including the first LTM configuration and the first service configuration to the UE via an SRB (e.g., SRB1). In some implementations, the SN request response message (first SN request message) includes a first cell ID indicating that the first LTM candidate configuration is associated with a first cell. In other implementations, the SN request response message includes the first cell ID in response to an SN request message including the first cell ID.

[0207] In some implementations, when or after preparing the first cell for LTM, the MN can prepare a second cell of the C-SN (i.e., the first C-SN) as an LTM candidate cell for the UE by sending a second SN request message to the C-SN, similar to box 905. In some implementations, the second SN request message includes the second cell ID of the second cell. In response, the MN receives a second SN request response message from the C-SN, which includes a second LTM candidate configuration for the second cell used for LTM, similar to box 907A. The MN obtains a second LTM CSI resource configuration for the CSI resources of the second cell and generates a second LTM CSI report configuration based on the second LTM CSI resource configuration, similar to boxes 962 and 964, respectively. In some implementations, the MN includes the second LTM candidate configuration, a second configuration ID identifying the second LTM candidate configuration, the second CSI resource configuration, and the second CSI report configuration in the first RRC message. The MN may include the second LTM CSI report configuration in the first service configuration or the first RRC message. In some implementations, the second configuration ID is the LTM candidate ID.

[0208] In other implementations, the MN sends at least one second RRC message to the UE, which includes a second LTM candidate configuration, a second CSI resource configuration, and a second CSI report configuration, similar to box 918. In some implementations, the MN may include the second LTM CSI report configuration in a second service configuration, and also include the second service configuration in the second RRC message. For example, the second service configuration is a cell group configuration (e.g., CellGroupConfig IE). The MN includes the second LTM configuration and the second service configuration in the second RRC message.

[0209] In some implementations, the second SN request message includes a second cell ID to indicate that the second LTM candidate configuration is associated with a second cell. In other implementations, the second SN request response message includes the second cell ID in response to a second SN request that includes the second cell ID.

[0210] In some implementations, when or after preparing the first cell for LTM, the MN can prepare a third cell of another C-SN (i.e., the second C-SN) as an LTM candidate cell for the UE by sending a third SN request message to the second C-SN, similar to box 905. In some implementations, the third SN request message includes the third cell ID of the third cell. In response, the MN receives a third SN request response message from the second C-SN, which includes a third LTM candidate configuration for configuring the third cell for LTM, similar to box 907A. The MN obtains a third LTM CSI resource configuration for configuring CSI resources for the third cell and generates a third LTM CSI report configuration based on the third LTM CSI resource configuration, similar to boxes 962 and 964, respectively. In some implementations, the MN includes the third LTM candidate configuration, a third configuration ID identifying the third LTM candidate configuration, and the third CSI resource configuration in the first LTM configuration, the second LTM configuration, the first RRC message, and / or the second RRC message. The MN may include a third LTM CSI report configuration in the first service configuration, the first RRC message, the second service configuration, or the second RRC message. In some implementations, the third configuration ID is an LTM candidate ID.

[0211] In other implementations, the MN sends at least one third RRC message to the UE, which includes a third LTM candidate configuration, a third configuration ID, a third CSI resource configuration, and a third CSI report configuration, similar to box 918. In some implementations, the MN generates a third LTM configuration, which includes a third LTM candidate configuration, a third configuration ID, and a third LTM CSI resource configuration. In some implementations, the MN includes a third LTM CSI report configuration in the third service configuration and also includes the third service configuration in the third RRC message. For example, the third service configuration is a cell group configuration (e.g., CellGroupConfig IE). The MN includes both the third LTM configuration and the third service configuration in the third RRC message.

[0212] In some implementations, the third SN request message includes a third cell ID to indicate that a third LTM candidate configuration is associated with a third cell. In other implementations, the third SN request response message includes a third cell ID in response to a third SN request that includes the third cell ID.

[0213] When the MN prepares the first cell and the second and / or the third cell simultaneously as described above, the MN can determine which SN request response message responds to which SN request message based on the cell ID in the SN request message and the SN request response message. In some implementations, the first RRC message, the second RRC message, and the third RRC message are RRC reconfiguration messages.

[0214] Figure 9B This is a flowchart of an example method 900B, similar to method 900A, except that method 900B includes block 907B instead of blocks 907A and 962. At block 907B, the MN receives an SN request response message from the C-SN, which includes a first LTM CSI resource configuration and a first LTM candidate configuration configuring the first cell as an LTM candidate cell for the UE. Unlike method 900A, in method 900B, the MN receives a first LTMCSI resource configuration from the C-SN that configures the CSI resources for the first cell.

[0215] Figure 10A This illustrates a method similar to method 900A that can be derived from MN (e.g., Figures 6A to 6DExample method 1000A is implemented by the CU of MN 104B. Method 1000A begins at block 1002, where the CU communicates with the UE under the DC of the MN and S-SN, wherein the CU communicates with the UE via S-DU. At block 1080-1, the CU may perform intra-DU LTM configuration and / or execution procedures (e.g., events 396, 380, 696, or 680) with the S-DU and the UE. At block 1080-2, the CU may perform inter-DU LTM configuration and / or execution procedures (e.g., events 496, 480, 696, or 680) with the C-DU and the UE. The process proceeds to blocks 905, 907A, and 962. At block 1012, the CU sends a CU-DU message including a first LTM CSI resource configuration to the S-DU. At block 1014, the CU receives a DU-CU message including a first LTM CSI report configuration from the S-DU. At frame 1018, the CU sends the first LTM configuration, the first LTM CSI resource configuration, and the first LTM CSI report configuration to the UE via the S-DU.

[0216] against Figure 9A The described examples and implementations can be applied to Figure 10A .

[0217] Figure 10B This is a flowchart of example method 1000B, which is similar to methods 1000A and 900B, except that method 1000B includes box 907B instead of boxes 907A and 962.

[0218] Figure 11 It shows that it can be generated by C-SN (e.g., Figures 6A to 6D Example method 1100 is implemented using C-SN 106A. Method 1100 begins at block 1105, where the C-SN receives from the MN an SN request message requesting preparation of a first cell as an LTM candidate cell for the UE. At block 1162, the C-SN obtains a first LTM CSI resource configuration that configures CSI resources for the first cell. At block 1107, the C-SN sends an SN request response message to the MN, which includes the first LTM candidate configuration and the first LTM CSI resource configuration, wherein the first LTM candidate configuration configures the first cell as an LTM candidate cell for the UE.

[0219] In some implementations, the C-SN receives the first LTM CSI resource configuration from a network node (e.g., OAM). In other implementations, the C-SN has the first LTM CSI resource configuration pre-configured in a storage device and obtains the first LTM CSI resource configuration from the storage device.

[0220] In some implementations, as described above, the C-SN can prepare a second cell as an LTM candidate cell for the UE.

[0221] Figure 12 It shows that it can be generated by C-SN (e.g., Figures 6A to 6D Example method 1200 is implemented by the CU of C-SN 106A. Method 1200 begins at block 1105, which is performed by the CU. At block 1262, the CU receives a DU-to-CU message from the DU, which includes a first LTM CSI resource configuration, wherein the first LTM CSI resource configuration configures the CSI resources for the first cell. Method 1200 ends at block 1107, which is performed by the CU.

[0222] The DU operates the first cell. In some implementations, the CU sends a CU-DU message to the DU and receives a DU-CU message from the DU in response. For example, the CU-DU message and the DU-CU message are respectively... UE Context Establishment Request Messages and UE context Establish a response Messages. In other implementations, CU to DU messages and DU to CU messages are respectively UE Context Modification Request Messages and UE context modification response In other implementations, the DU to CU message is an F1 setup request message, and in response, the CU sends an F1 setup response message to the DU. In yet another implementation, the DU to CU message is... GNB-DU Configuration Update The CU sends a message to the DU in response. GNB-DU Configuration Update Response Message. In other implementations, the DU to CU message is GNB-CU Configuration Update Response information.

[0223] against Figures 7A to 10B The described examples and implementations can be applied to Figure 11 and Figure 12 .

[0224] Figure 13A A method similar to method 700A is shown that can be generated by S-SN (e.g., Figures 6A to 6DExample method 1300A implemented by S-SN 104A differs in that method 1300A includes blocks 1372, 1374, 1318, and 1324 instead of blocks 762, 764, 718, and 724. At block 1372, the S-SN obtains first SSB information for a first cell, wherein the first SSB information includes the time and frequency configurations of one or more SSBs transmitted on the first cell. At block 1374, the S-SN generates a first LTM SSB configuration based on the first SSB information. At block 1318, the S-SN sends a first LTM candidate configuration and a first LTM SSB configuration to the UE. At block 1324, the S-SN receives from the UE one or more L1 measurement reports, each including measurement results for the SSBs configured in the first SSB configuration.

[0225] In some implementations, the S-SN obtains or receives SSB information from a network node (e.g., OAM). In other implementations, the S-SN has first SSB information pre-configured in a storage device and obtains the first SSB information from the storage device. In some implementations, the first SSB information is LTM SSB information.

[0226] In some implementations, the S-SN generates at least one first RRC message to the UE, including a first LTM candidate configuration, a first configuration ID, and a first LTM SSB configuration. The first configuration ID identifies the first LTM candidate configuration and / or the first LTM SSB configuration. In some implementations, the S-SN generates a first LTM configuration including the first LTM candidate configuration, the first configuration ID, and the first LTM SSB configuration. In some implementations, the first configuration ID is the LTM candidate ID. At block 1318, the S-SN sends the first RRC message including the first LTM configuration to the UE.

[0227] In some implementations, when or after preparing a first cell as an LTM candidate cell for the UE, the S-SN can prepare a second cell of the C-SN (i.e., the first C-SN) as an LTM candidate cell for the UE by sending a second SN request message to the MN, similar to box 703. In response, the S-SN receives a second SN confirmation message from the MN, which includes a second LTM candidate configuration for the second cell used for LTM, similar to box 709A. The S-SN obtains second SSB information for the UE, which includes the time and frequency configuration of one or more SSBs transmitted on the second cell, similar to box 1372. The second SSB information may be LTM SSB information. The S-SN generates a second LTM SSB configuration based on the second SSB information, similar to box 1374. Alternatively, the S-SN obtains the second LTM SSB configuration, for example, from a network node or storage device, instead of the second SSB information. In some implementations, the S-SN includes the second LTM candidate configuration, a second configuration ID, and the second LTM SSB configuration in the first RRC message or the first LTM configuration. The second configuration ID identifies the second LTM candidate configuration and / or the second LTM SSB configuration. In some implementations, the second configuration ID is the LTM candidate ID.

[0228] In other implementations, the S-SN sends at least one second RRC message to the UE, which includes a second LTM candidate configuration, a second configuration ID, and a second LTM SSB configuration, similar to box 1318. In some implementations, the S-SN generates a second LTM configuration, which includes a second LTM candidate configuration, a second configuration ID, and a second LTM SSB configuration. The S-SN includes the second LTM configuration in the second RRC message.

[0229] In some implementations, the second SN request message and the second SN confirmation message can be combined with the first SN request message and the SN confirmation message, respectively, as a single SN request message and a single SN confirmation message.

[0230] In some implementations, when or after preparing the first cell for LTM, the S-SN can prepare a third cell of another C-SN (i.e., the second C-SN) as an LTM candidate cell for the UE by sending a third SN request message to the MN, similar to box 703. In response, the S-SN receives a third SN confirmation message from the MN, which includes a third LTM candidate configuration for the third cell used for LTM, similar to box 709A. The S-SN obtains third SSB information for the UE, which includes the time and frequency configuration of one or more SSBs transmitted on the third cell, similar to box 1372. The third SSB information may be LTM SSB information. The S-SN generates a third LTM SSB configuration based on the third SSB information, similar to box 1374. Alternatively, the S-SN obtains the third LTM SSB configuration, for example, from a network node or storage device, instead of the third SSB information. In some implementations, the S-SN includes a third LTM candidate configuration, a third configuration ID, and a third LTM SSB configuration in the first LTM configuration, the second LTM configuration, the first RRC message, and / or the second RRC message. The third configuration ID identifies the third LTM candidate configuration and / or the third LTM SSB configuration. In some implementations, the third configuration ID is the LTM candidate ID.

[0231] In other implementations, the S-SN sends at least one third RRC message to the UE, which includes a third LTM candidate configuration, a third configuration ID, and a third LTM SSB configuration, similar to box 1318. In some implementations, the S-SN generates a third LTM configuration, which includes a third LTM candidate configuration, a third configuration ID, and a third LTM SSB configuration. The S-SN includes the third LTM configuration in the third RRC message.

[0232] Figure 13B This illustrates a method similar to method 1300A that can be generated by S-SN (e.g., Figures 6A to 6D Example method 1300B is implemented in S-SN 104A, the difference being that method 1300A includes box 1309B instead of boxes 709A and 1372.

[0233] At box 1309B, the S-SN receives an SN confirmation message from the MN, which includes a first LTM candidate configuration and a first SSB information for the UE, wherein the first LTM candidate configuration configures a first cell for LTM, and the first SSB information includes the time and frequency configuration of one or more SSBs transmitted on the first cell.

[0234] against Figure 7A The described examples and implementations can be applied to Figure 13A and Figure 13B . Figure 13A or Figure 13B Can be with Figure 7A or Figure 7B Combined.

[0235] Figure 14 This illustrates a method similar to 1100 that can be generated by a C-SN (e.g., Figures 6A to 6D Example method 1400 is implemented using C-SN 106A, except that method 1400 includes blocks 1472 and 1474 instead of block 1162. The method begins at block 1105 and proceeds to blocks 1472 and 1474, which are similar to blocks 1372 and 1374, respectively. At block 1407, the C-SN sends an SN request response message to the MN, which includes a first LTM candidate configuration and a first LTM SSB configuration, wherein the first LTM candidate configuration configures a first cell as an LTM candidate cell for the UE.

[0236] In some implementations, the C-SN receives the first SSB information from a network node (e.g., OAM). In other implementations, the C-SN has the first SSB information pre-configured in a storage device and obtains the first SSB information from the storage device. In some alternative implementations, the C-SN obtains the first LTM SSB configuration instead of the first SSB information. In such cases, skip box 1474.

[0237] against Figure 7A , Figure 7B and Figure 11 The described examples and implementations can be applied to Figure 14 . Figure 14 Can be with Figure 11 Combined. Targeting Figure 13A and Figure 13B The examples and implementations described in the S-SN section can be applied to Figure 14 The C-SN in. For example, in cases such as those targeting Figure 13A When preparing the second cell with the S-SN, the C-SN obtains the second SSB information and generates the second LTM SSB configuration based on the second SSB information instead of the S-SN. Alternatively, the C-SN obtains the second LTM SSB configuration, for example, from a network node or storage device, instead of the second SSB information. The C-SN includes the second LTM SSB configuration in the second SN request response message.

[0238] Figure 15 Methods similar to 1100, 1200, and 1400 are shown that can be generated by a C-SN (e.g., Figures 6A to 6D Example method 1500 of the CU implementation of C-SN 106A.

[0239] Method 1500 begins at block 1105 and proceeds to block 1572. At block 1572, the CU receives a DU-to-CU message from the DU including first SSB information, wherein the first SSB information includes the time and frequency configuration of one or more SSBs transmitted on the first cell. The process proceeds from block 1572 to blocks 1474 and 1407.

[0240] In some implementations, the DU first obtains or receives the first SSB information from a network node (e.g., OAM). In other implementations, the DU has the first SSB information pre-configured in a storage device and obtains the first SSB information from the storage device.

[0241] against Figure 7A , Figure 7B , Figure 11 , Figure 12 and Figure 14 The described examples and implementations can be applied to Figure 15 . Figure 15 Can be with Figure 12 Combined. Targeting Figure 13A and Figure 13B The examples and implementations described in the S-SN section can be applied to Figure 15 The CU. For example, in cases such as those targeting Figure 13A When preparing a second cell with the S-SN, the C-SN's CU receives the second SSB information from the DU to CU message and generates a second LTM SSB configuration based on the second SSB information. Alternatively, the C-SN's CU obtains the second LTM SSB configuration from the DU to CU message instead of the second SSB information. The C-SN includes the second LTM SSB configuration in the first or second SN request-response message.

[0242] The following descriptions can be applied to the descriptions above.

[0243] In some implementations, the SN requirement message and the SN acknowledgment message are respectively SN Change Requirements Messages and SN change confirmed recognize Message. In other implementations, the SN requirement message and the SN acknowledgment message are respectively SN Modification Requirements Messages and SN modification confirmed recognize Messages. In some implementations, the SN request message and the SN request response message are respectively... SN Add Request Messages and SN Add Add request and response Messages. In other implementations, the SN request message and the SN request response message are respectively SN Modification Request Messages and SN Modification Request Response information.

[0244] Generally, a description of one of the above figures can be applied to another of the above figures. If there is no conflict, the examples, implementations, and methods described above can be combined. The events or boxes described above can be optional or omitted. For example, the events or boxes with dashed lines in the figures can be optional. Descriptions from the perspective of the receiving node also apply to the sending node. For example, a description of a receiving node (e.g., DU) receiving a message from a sending node (e.g., CU) can be replaced by the sending node sending a message to the receiving node. Similarly, a description of a receiving node (e.g., CU) receiving a message from a sending node (e.g., DU) can be replaced by the sending node sending a message to the receiving node.

[0245] In some implementations, "message" is used and can be replaced with "information element (IE)" and vice versa. In some implementations, "IE" is used and can be replaced with "field" and vice versa. In some implementations, "configuration" can be replaced with "configurations" or "configuration parameters" and vice versa. In some implementations, "LTM command" can be replaced with "serving cell change command," "Layer 1 / Layer 2 LTM cell handover command," "lower layer handover command," or "lower layer serving cell change command." In some implementations, "some" means "one or more." In some implementations, "at least one" means "one or more." In some implementations, "DU configuration" can be replaced with "cell group configuration." In some implementations, "cell index" can be replaced with "serving cell index," "LTM cell index," "special cell (SpCell) index," "PCell index," or "PSCell index." In some implementations, "service" can be replaced with "source." In some implementations, "measurement report" can be replaced with "measurement result" or "CSI report". In some implementations, "early TA acquisition" can be replaced with "early UL timing synchronization" or "early UL synchronization". In some implementations, "early TA acquisition on / on the candidate cell" can be replaced with "with the candidate cell / with the candidate cell's early UL timing synchronization" or "with the candidate cell / with the candidate cell's early UL synchronization". In some implementations, "include" can be replaced with "comprise". In some implementations, "exclude" can be replaced with "avoid including". In some implementations, the above " cut Change request "and" Switching between request and response "This is used to illustrate the invention and can be replaced by a message with a common name. For example, " Switching requests "and" Switching between request and response"This can be replaced with the first CU-to-CU message and the second CU-to-CU message, respectively. In another example," Switching requests "and" Switching between request and response "It can be replaced by the first interface message and the second interface message respectively. In yet another example," Switching requests "and" Switching between request and response "These can be replaced by a first BS to BS message and a second BS to BS message, respectively. In some implementations, the terms "SN request," "SN confirmation," "SN request," and "SN request response" are used to describe the invention and can be replaced by messages with common names. For example, "SN request message" can be replaced by an SN to MN message. In another example, "SN confirmation message" can be replaced by an MN to SN message."

[0246] The user device in which the technologies of this disclosure are implemented (e.g., UE 102) can be any suitable device capable of wireless communication, such as a smartphone, tablet computer, laptop computer, mobile game console, point-of-sale (POS) terminal, health monitoring device, drone, camera, media streaming dongle or other personal media device, wearable device (such as a smartwatch), wireless hotspot, femtocell, or broadband router. Further, in some cases, the user device can be embedded in an electronic system (such as the main unit of a vehicle or an advanced driver assistance system (ADAS)). Further still, the user device can operate as an Internet of Things (IoT) device or a mobile internet device (MID). Depending on the type, the user device may include one or more general-purpose processors, computer-readable storage, a user interface, one or more network interfaces, one or more sensors, etc.

[0247] Some embodiments described in this disclosure include logic or multiple components or modules. A module can be a software module (e.g., code or machine-readable instructions stored on a non-transitory machine-readable medium) or a hardware module. A hardware module is a tangible unit capable of performing certain operations and can be configured or arranged in a certain way. A hardware module may include a dedicated circuit system or logic (e.g., as a dedicated processor, such as a field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC), digital signal processor (DSP), etc.) that is persistently configured to perform certain operations. A hardware module may also include programmable logic or circuit systems (e.g., as contained within 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 persistently configured circuit system or in a temporarily configured circuit system (e.g., configured by software) may be driven by cost and time considerations.

[0248] When implemented in software, these technologies can be provided as part of an operating system, a library used by multiple applications, or a specific software application. The software can be executed by one or more general-purpose processors or one or more dedicated processors.

[0249] Upon reading this disclosure, those skilled in the art will understand additional and alternative structural and functional designs for handling mobility between base stations using the principles disclosed herein. Therefore, while specific embodiments and applications have been shown and described, it should be understood that the disclosed embodiments are not limited to the precise constructions and components disclosed herein. Various modifications, alterations, and variations that will be apparent to those skilled in the art may be made to the arrangement, operation, and details of the methods and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims.

[0250] The following examples are illustrative only and can be combined with other examples or teachings described herein without limitation.

[0251] Example 1 is a method for wireless communication performed by a Radio Access Network (RAN) node, the method comprising: sending a Secondary Node (SN) Request message to a Primary Node (MN); receiving an SN Response message from the MN in response to the SN Request message, the SN Response message including a Low-Layer Triggered Mobility (LTM) Candidate Cell Configuration; generating a Channel State Information (CSI) Report Configuration based on a Reference Signal Resources Configuration; and sending the LTM Candidate Cell Configuration, the Reference Signal Resources Configuration, and the CSI Report Configuration associated with the LTM Candidate Cell to a User Equipment (UE).

[0252] Example 2 can be combined with Example 1 and further includes: obtaining the reference signal resource configuration associated with the LTM candidate cell.

[0253] Example 3 can be combined with Example 1 and further includes: configuring the CSI report configuration associated with the LTM candidate cell based on the reference signal resource configuration.

[0254] Example 4 can be combined with Example 1 and further includes: the SN response message further includes the reference signal resource configuration that configures the CSI resources associated with the LTM candidate cell.

[0255] Example 5 can be combined with Example 1 and further includes: the SN request message includes the identifier ID of the first cell.

[0256] Example 6 can be combined with any of Examples 1 to 2, and further includes: the reference signal resource configuration indicates a resource for at least one of the following: CSI reference signal CSI-RS or synchronization signal block SSB.

[0257] Example 7 can be combined with Example 6 and further includes: the SSB indicates the time and frequency configuration of one or more SSBs transmitted on the LTM candidate cell.

[0258] Example 8 may be combined with Example 7 and further includes receiving the SSB from at least one of the following: a memory for operating, managing and maintaining the OAM node or the RAN node.

[0259] Example 9 can be combined with any of Examples 1 to 8, and further includes: receiving a measurement report from the UE based on the CSI report configuration and the reference signal resource configuration.

[0260] Example 10 can be combined with any of Examples 1 to 9, and further includes: the measurement report includes measurement information associated with the one or more SSBs transmitted on the LTM candidate cell.

[0261] Example 11 can be combined with any of Examples 1 to 10, and further includes: sending an LTM cell handover command to the UE for handing over to the LTM candidate cell; sending at least one of the following to the MN: a cell handover notification message or an early state delivery message; and receiving an LTM success message from the MN.

[0262] Example 12 can be combined with any of Examples 1 to 11, and further includes: sending the CSI report configuration, the reference signal resource configuration, and the LTM candidate cell configuration associated with the LTM candidate cell by sending the CSI report configuration, the reference signal resource configuration, and the LTM configuration in a Radio Resource Control (RRC) reconfiguration message.

[0263] Example 13 can be combined with any of Examples 1 to 12, and further includes: the RAN node includes source auxiliary nodes S-SN.

[0264] Example 14 can be combined with any of Examples 1 to 13, and further includes: the RAN node communicating with the UE located under a dual-connection DC with the MN.

[0265] Example 15 is a method for wireless communication performed by a Radio Access Network (RAN) node, the method comprising: sending a Secondary Node (SN) Request message to a Primary Node (MN); receiving an SN Response message from the MN in response to the SN Request message, the SN Response message including a Low Layer Triggered Mobility (LTM) candidate cell configuration; obtaining a Reference Signal Resource Configuration associated with the LTM candidate cell; sending a CU-DU message including the Reference Signal Resource Configuration from a Central Unit (CU) of the RAN node to a Distributed Unit (DU) of the RAN node; receiving a DU-CU message including a Channel State Information (CSI) Report Configuration from the DU by the CU; and sending the LTM candidate cell configuration, the Reference Signal Resource Configuration, and the CSI Report Configuration to a User Equipment (UE).

[0266] Example 16 can be combined with Example 15 and further includes: the SN response message further includes a reference signal resource configuration associated with the LTM candidate cell, which configures the CSI resources associated with the LTM candidate cell.

[0267] Example 18 is the method as described in any of claims 15 to 17, and further includes: the CU to DU message further indicating a configuration identifier ID and a cell ID.

[0268] Example 19 can be combined with any of Examples 15 to 18, and further includes: the RAN node includes a source-secondary RAN node S-SN.

[0269] Example 17 can be combined with Example 15 and further includes: receiving a reference signal resource configuration associated with the LTM candidate cell.

[0270] Example 20 is a method for wireless communication performed by a radio access network (RAN) node, the method comprising: sending an SN request message to a candidate secondary node (C-SN); and receiving an SN request response message from the C-SN in response to the SN request message, the SN request response message including a low-layer triggered mobility LTM candidate cell configuration.

[0271] Example 21 can be combined with Example 20 and further includes: the SN response message further includes a reference signal resource configuration that configures the Channel State Information (CSI) resources associated with the LTM candidate cell.

[0272] Example 22 can be combined with Example 20 and further includes: receiving reference signal resource configuration associated with LTM candidate cells.

[0273] Example 23 can be combined with Example 22 and further includes sending the LTM candidate cell configuration, the reference signal resource configuration, and the channel state information (CSI) report configuration associated with the LTM candidate cell to the user equipment (UE).

[0274] Example 24 is the method as described in any of claims 20 to 23, and further includes: receiving from the UE a measurement report based on the CSI report configuration associated with the LTM candidate cell.

[0275] Example 25 is the method of any of claims 20 to 24, and further includes: sending an SN message to the source secondary node S-SN, the SN message including the LTM candidate cell configuration and the reference signal resource configuration associated with the LTM candidate cell.

[0276] Example 26 can be combined with any of Examples 20 to 25, and further includes: the RAN node includes a master node MN.

[0277] Example 27 is a method for wireless communication performed by a Radio Access Network (RAN) node, the method comprising: sending an SN request message to a candidate secondary node (C-SN); and receiving an SN request response message from the C-SN in response to the SN request message, the SN request response message including a low-layer triggered mobility LTM candidate cell configuration; sending a CU-DU message indicating reference signal resource configuration from a central unit (CU) of the RAN node to a distributed unit (DU) of the RAN node; and receiving a Channel State Information (CSI) report configuration from the DU by the CU.

[0278] Example 28 can be combined with Example 27 and further includes: receiving the reference signal resource configuration associated with the LTM candidate cell.

[0279] Example 29 can be combined with Example 27 and further includes: the SN response message further includes the reference signal resource configuration that configures the Channel State Information (CSI) resources associated with the LTM candidate cell.

[0280] Example 30 can be combined with any of Examples 27 to 29, and further includes: the RAN node includes a master node MN.

[0281] Example 31 is a method of wireless communication performed by a radio access network (RAN) node, the method comprising: receiving a handover request message from a master node (MN); and sending a handover request response message to the MN, the handover request response message indicating a lower-layer triggered mobility LTM candidate cell configuration and a reference signal resource configuration associated with the LTM candidate cell.

[0282] Example 32 may be combined with Example 31 and further includes: the reference signal resource configuration indicates a resource for at least one of the following: CSI reference signal CSI-RS or synchronization signal block SSB.

[0283] Example 33 can be combined with Example 32 and further includes: the SSB indicates the time and frequency configuration of one or more SSBs transmitted on the LTM candidate cell.

[0284] Example 34 is a method of wireless communication performed by a Radio Access Network (RAN) node, the method comprising: receiving a handover request message from a master node (MN); obtaining a DU-CU message including a reference signal resource configuration associated with an LTM candidate cell from a distributed unit (DU) of the RAN node by a central unit (CU) of the RAN node; and sending a handover request response message to the MN, the handover request response message including a low-layer triggered mobility LTM candidate cell configuration and the reference signal resource configuration associated with the LTM candidate cell.

[0285] Example 35 may be combined with Example 34 and further includes: the reference signal resource configuration indicates a resource for at least one of the following: CSI reference signal CSI-RS or synchronization signal block SSB.

[0286] Example 36 can be combined with any of Examples 34 to 35, and further includes: sending a User Equipment Context Establishment Request message from the CU to the DU; and receiving a UE Context Establishment Response message from the DU.

[0287] Example 37 can be combined with any of Examples 34 to 36, and further includes: sending a User Equipment Context Modification Request message from the CU to the DU; and receiving a UE Context Modification Response message from the DU.

[0288] Example 38 can be combined with any of Examples 34 to 37, and further includes: receiving a next-generation node B GNB-DU configuration update message from the DU; and sending a GNB-DU configuration update response message from the CU to the DU.

[0289] Example 39 can be combined with any of Examples 34 to 38, and further includes: the RAN node includes a candidate secondary node C-SN.

[0290] Example 40 is an apparatus for wireless communication, the apparatus being used to implement the method as described in any one of Examples 1 to 39.

[0291] Example 41 is an apparatus for wireless communication, the apparatus including components for implementing the method as described in any one of Examples 1 to 39.

[0292] Example 42 is a non-transitory computer-readable medium storing computer-executable code that, when executed by a processor, causes the processor to implement the method as described in any one of Examples 1 to 39.

[0293] Example 43 is a computer program product for implementing the method as described in any one of Examples 1 to 39.

Claims

1. A method for wireless communication performed by a radio access network (RAN) node (104A), the method comprising: Send a (603, 703) secondary node SN request message to the primary node MN (104B); In response to the SN request message, an SN response message (609A, 709A) is received from the MN, the SN response message including a low-layer triggered mobility LTM candidate cell configuration; Configuration for generating Channel State Information (CSI) reports associated with LTM candidate cells based on reference signal resource configuration; as well as Send (718) the LTM candidate cell configuration, the reference signal resource configuration and the CSI report configuration associated with the LTM candidate cell to the user equipment (UE) (102).

2. The method of claim 1, further comprising: Obtain (762) the reference signal resource configuration associated with the LTM candidate cell, wherein the CSI report configuration associated with the LTM candidate cell is configured based on the reference signal resource configuration.

3. The method as described in claim 1, wherein, The SN request message includes the identifier ID of the first cell.

4. The method according to any one of claims 1 to 3, further comprising: The UE (102) receives (724) a measurement report based on the CSI report configuration and the reference signal resource configuration, wherein the measurement report includes measurement information associated with one or more synchronization signal blocks (SSBs) transmitted on the LTM candidate cell.

5. The method according to any one of claims 1 to 4, further comprising: Send an LTM cell handover command to the UE (102) for switching to the LTM candidate cell; Send at least one of the following to the MN: Cell handover notification message; or Early state passing messages; and Receive an LTM success message from the MN.

6. The method of claim 1, further comprising: The central unit (CU) of the RAN node sends a CU-DU message (812) including the reference signal resource configuration to the distributed unit (DU) of the RAN node; as well as The CU receives (814) a DU-to-CU message including the Channel State Information (CSI) report configuration from the DU.

7. A method for wireless communication performed by a radio access network (RAN) node (104), the method comprising: Send a (905) SN request message to the candidate secondary node C-SN; as well as In response to the SN request message, a (907A) SN request response message is obtained from the C-SN, the SN request response message including the low-layer triggered mobility LTM candidate cell configuration.

8. The method of claim 7, further comprising: Receive (962) the reference signal resource configuration associated with the LTM candidate cell.

9. The method of claim 8, further comprising: Send (918) the LTM candidate cell configuration, the reference signal resource configuration, and the channel state information (CSI) report configuration associated with the LTM candidate cell to the user equipment (UE) (102); as well as Receive (924) a measurement report based on the CSI report configuration associated with the LTM candidate cell from the UE (102).

10. The method of any one of claims 7 to 9, further comprising: Send a (909A) SN message to the source auxiliary node S-SN, the SN message including the LTM candidate cell configuration and the reference signal resource configuration associated with the LTM candidate cell.

11. The method of claim 8, further comprising: The central unit (CU) of the RAN node sends a (1012) CU-DU message indicating the configuration of the reference signal resources to the distributed unit (DU) of the RAN node; and The CU receives (1014) Channel State Information (CSI) report configuration from the DU.

12. The method of claim 7, further comprising: The central unit (CU) of the RAN node (106A) obtains a DU-to-CU message from the distributed unit (DU) of the RAN node (106), which includes the reference signal resource configuration associated with the LTM candidate cell.

13. The method of claim 12, further comprising: Receive DU configuration update messages from the DU; as well as Send a DU configuration update response message to the DU.

14. A method for wireless communication performed by a radio access network (RAN) node (106), the method comprising: Receive a handover request message from the master node MN (104A); as well as A handover request response message is sent to the MN (104A), the handover request response message indicating the lower layer trigger mobility LTM candidate cell configuration and the reference signal resource configuration associated with the LTM candidate cell.

15. The method of claim 14, wherein, The reference signal resource configuration indicates resources used for at least one of the following: CSI reference signal CSI-RS; or Synchronization Signal Block (SSB), wherein the SSB indicates the time and frequency configuration of one or more SSBs transmitted on the LTM candidate cell.

16. An apparatus for wireless communication, the apparatus comprising a memory and at least one processor, the at least one processor being coupled to the memory and configured to implement the method as claimed in any one of claims 1 to 15.

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