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WO2025072577A1 - Gestion de la mobilité pour un équipement utilisateur - Google Patents

Gestion de la mobilité pour un équipement utilisateur Download PDF

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Publication number
WO2025072577A1
WO2025072577A1 PCT/US2024/048738 US2024048738W WO2025072577A1 WO 2025072577 A1 WO2025072577 A1 WO 2025072577A1 US 2024048738 W US2024048738 W US 2024048738W WO 2025072577 A1 WO2025072577 A1 WO 2025072577A1
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WO
WIPO (PCT)
Prior art keywords
ltm
configuration
implementations
cell
message
Prior art date
Application number
PCT/US2024/048738
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English (en)
Inventor
Chih-Hsiang Wu
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Google Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
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Publication of WO2025072577A1 publication Critical patent/WO2025072577A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W8/00—Network data management
    • H04W8/22—Processing or transfer of terminal data, e.g. status or physical capabilities
    • H04W8/24—Transfer of terminal data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0055—Transmission or use of information for re-establishing the radio link
    • H04W36/0069—Transmission or use of information for re-establishing the radio link in case of dual connectivity, e.g. decoupled uplink/downlink
    • H04W36/00698—Transmission or use of information for re-establishing the radio link in case of dual connectivity, e.g. decoupled uplink/downlink using different RATs

Definitions

  • This disclosure relates to wireless communications and, more particularly, to managing mobility for a user equipment.
  • the Packet Data Convergence Protocol (PDCP) sublayer of the radio protocol stack provides services such as transfer of user-plane data, ciphering, integrity protection, etc.
  • the PDCP layer 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 sequencing of protocol data units (PDUs) in the uplink direction (from a user device, also known as a user equipment (UE), to a base station) as well as in the downlink direction (from the base station to the UE).
  • EUTRA Evolved Universal Terrestrial Radio Access
  • NR New Radio
  • the PDCP sublayer provides signaling radio bearers (SRBs) and data radio bearers (DRBs) to the Radio Resource Control (RRC) sublayer.
  • SRBs signaling radio bearers
  • DRBs data radio bearers
  • RRC Radio Resource Control
  • the UE and a base station can use SRBs to exchange RRC messages as well as non-access stratum (NAS) messages, and can use DRBs to transport data on a user plane.
  • SRBs signaling radio bearers
  • DRBs Radio Resource Control
  • NAS non-access stratum
  • UEs can use several types of SRBs and DRBs.
  • DC dual connectivity
  • the cells associated with the base station operating the master node (MN) define a master cell group (MCG)
  • MCG master cell group
  • SN secondary node
  • SCG secondary cell group
  • So-called SRB1 resources carry RRC messages, which in some cases include NAS messages over the dedicated control channel (DCCH)
  • DCCH dedicated control channel
  • SRB2 resources support RRC messages that include logged measurement information or NAS messages, also over the DCCH but with lower priority than SRB1 resources.
  • SRB1 and SRB2 resources allow the UE and the MN to exchange RRC messages related to the MN and embed RRC messages related to the SN, and also can be referred to as MCG SRBs.
  • SRB3 resources allow the UE and the SN to exchange RRC messages related to the SN, 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 the SN.
  • DRBs using the lower-layer resources of only the MN can be referred as MCG DRBs
  • DRBs using the lower-layer resources of only the SN can be referred as SCG DRBs
  • DRBs using the lower-layer resources of both the MCG and the SCG can be referred to as split DRBs.
  • the UE in some scenarios can concurrently utilize resources of multiple radio access network (RAN) nodes (e.g., base stations or components of a distributed base station), interconnected by a backhaul.
  • RAN radio access network
  • RATs radio access technologies
  • this type of connectivity is referred to as Multi-Radio Dual Connectivity (MR-DC).
  • MN master node
  • SN secondary node
  • PSCell primary secondary cell
  • the UE communicates with the MN (via the PCell) and the SN (via the PSCell).
  • the UE utilizes 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 can determine to hand the UE over to the second base station, and initiate a handover procedure.
  • the RAN configures the UE to transmit Layer 3 (L3) measurement results. Based on L3 measurement results received from the UE, the RAN transmits a RRC reconfiguration message configuring Reconfiguration with Synchronization (e.g., the RRC reconfiguration message includes ⁇ ReconfigurationWithSync IE) for change of the serving cell (e.g., PCell or PSCell).
  • L3 Layer 3
  • the RRC reconfiguration message includes ⁇ ReconfigurationWithSync IE for change of the serving cell (e.g., PCell or PSCell).
  • the RAN In cases where the UE operates in carrier aggregation (CA) of at least one secondary cell (SCell) with the PCell or PSCell, the RAN has to release the at least one SCell due to the change of the PCell or PSCell.
  • the serving cell change involves complete L2 (and LI) resets, leading to longer latency, larger overhead and longer interruption time.
  • LTM low-layer triggered mobility
  • RAN nodes and UEs can support LTM in single connectivity scenarios and dual connectivity scenarios. It is not clear about how a UE can indicate, to the RAN and/or the core network (CN), support or non-support of LTM in a single connectivity scenario or a dual connectivity scenario. Without information about the ability of a UE to support LTM in certain scenarios, the RAN cannot correctly configure LTM for the UE.
  • CN core network
  • An example embodiment of the techniques of this disclosure is a configuration method implemented in a radio access network (RAN) node.
  • the method comprises receiving, from a user equipment (UE), a first indication of lower-layer triggered mobility (LTM) capability of the UE, for a first cell group (CG); receiving, from the UE, a second indication of LTM capability of the UE, for a second CG; configuring the UE with a first LTM configuration for the first CG in accordance with the first indication; and configuring the UE with a second LTM configuration for the second CG in accordance with the second indication.
  • LTM lower-layer triggered mobility
  • Another example embodiment of these techniques is a configuration method implemented in a user equipment (UE).
  • the method comprises transmitting, to a radio access network (RAN), a first indication of lower-layer triggered mobility (LTM) capability of the UE, for a first cell group (CG); transmitting, to the RAN, a second indication of LTM capability of the UE, for a second CG; receiving, from the RAN and in response to the transmitting of the first indication, a first LTM configuration for the first CG; and receiving, from the RAN and in response to the transmitting of the second indication, a second LTM configuration for the second CG.
  • RAN radio access network
  • LTM lower-layer triggered mobility
  • Still another example embodiment of these techniques is a wireless communication device comprising processing hardware and configured to implement one of methods above.
  • Fig. 1 A is a block diagram of an example system in which a radio access network (RAN) and a user device can implement the techniques of this disclosure for managing lower-layer triggered mobility (LTM) configurations related to multiple cell groups;
  • Fig. IB is a block diagram of an example base station including a centralized unit (CU) and a distributed unit (DU) that can operate in the system of Fig. 1 A;
  • CU centralized unit
  • DU distributed unit
  • Fig. 2A is a block diagram of an example protocol stack according to which the UE of Fig. 1 A communicates with base stations;
  • FIG. 3 is a messaging diagram of an example scenario in which a UE receives an LTM configuration from a distributed unit (DU) of a distributed base station and accesses a candidate cell of the DU in accordance with the LTM configuration;
  • DU distributed unit
  • Fig. 4 is a messaging diagram of an example scenario generally similar to that of Fig. 3, but in which the candidate cell is associated with another DU of the distributed base station;
  • Fig. 5A is a messaging diagram of an example scenario generally similar to that of Fig. 3, but in which the UE operates in dual connectivity, and the candidate cell is associated with a secondary node (SN);
  • SN secondary node
  • Fig. 5B is a messaging diagram of an example scenario generally similar to that of Fig. 5 A, but in which the SN performs LTM configuration via the main node (MN) rather than directly;
  • MN main node
  • Fig. 6A is a messaging diagram of an example scenario generally similar to that of Fig. 3, but in which the UE operates in dual connectivity, and the candidate cell is associated with a secondary node (SN);
  • SN secondary node
  • Fig. 6B is a messaging diagram of an example scenario generally similar to that of Fig. 6A, but in which the SN performs LTM configuration via the MN rather than directly;
  • Fig. 7A is a messaging diagram of an example scenario generally similar to that of Fig. 4, but in which the MN and the SN are implemented in a same base station;
  • Fig. 7B is a messaging diagram of an example scenario generally similar to that of Fig. 7A, but in which the SN performs LTM configuration via the MN DU (M-DU) rather than directly;
  • Fig. 8A is a messaging diagram of an example scenario generally similar to that of Fig. 3, but in which the MN and the SN are implemented in different respective DUs of a same base station, and the candidate cell is associated with yet another DU of the distributed base station;
  • Fig. 8B is a messaging diagram of an example scenario generally similar to that of Fig. 9A, but in which the SN performs LTM configuration via the M-DU rather than directly;
  • FIG. 9 is a flow diagram of an example method for configuring a UE with respective LTM configurations for two cell groups, which can be implemented in a RAN of Fig. 1 A;
  • Fig. 10A is a flow diagram of an example method for configuring a UE for LTM for two cell groups in view of coordination information, which can be implemented in a RAN ofFig. 1A;
  • Fig. 10B is a flow diagram of an example method generally similar to that ofFig. 10 A, but according to which the RAN receives an LTM capability indication that applies to both the first cell group and the second cell group;
  • FIG. 11 A is a flow diagram of an example method for causing the SN to release UE resources after the UE completes an LTM cell switch, which can be implemented in a base station ofFig. 1A operating as an MN;
  • Fig. 1 IB is a flow diagram of an example method generally similar to that ofFig.
  • Fig. 12A is a flow diagram of an example method for causing a DU to release UE resources after the UE completes an LTM cell switch to another DU, which can be implemented in a CU of a distributed base station ofFig. 1A;
  • Fig. 12B is a flow diagram of an example method generally similar to that ofFig. 12 A, but according to which the CU instructs the DU to release UE resources after transmitting an LTM configuration to the UE;
  • Fig. 13 is a flow diagram of an example method for determining whether to configure LTM for a UE based on whether the UE is operating in DC, which can be implemented in a RAN node ofFig. 1 A;
  • Fig. 14 is a flow diagram of an example method for determining whether to configure LTM for a UE based on whether another RAN node configured LTM for the UE, which can be implemented in a RAN node ofFig. 1 A;
  • Fig. 15 is a flow diagram of an example method for configuring LTM for a UE currently operating in DC with an MN and an SN, which can be implemented in a RAN node ofFig. 1A;
  • FIG. 16 is a flow diagram of an example method for receiving respective LTM configurations for two cell groups, which can be implemented in a UE ofFig. 1 A;
  • Fig. 17 is a flow diagram of an example method for reporting, to the RAN, UE capability with respect to LTM for a particular cell group, which can be implemented in a UE ofFig. 1A;
  • Fig. 18 is a flow diagram of an example method for reporting, to the RAN in a NAS message, UE capability with respect to LTM for a particular cell group, which can be implemented in a UE of Fig. 1 A.
  • Fig. 1 A depicts an example wireless communication system 100 in which communication devices can implement these techniques.
  • the wireless communication system 100 includes a UE 102, a base station (BS) 104, a base station 106 and a core network (CN) 110.
  • the UE 102 initially connects to the base station 104.
  • the base station 104 can perform an SN addition to configure the UE 102 to operate in dual connectivity (DC) with the base station 104 and the base station 106.
  • the base stations 104 and 106 operate as an MN and an SN for the UE 102, respectively.
  • the base station 104 can be implemented as a master eNB (MeNB) or a master gNB (MgNB), and the base station 106 can be implemented as a secondary gNB (SgNB).
  • the UE 102 can communicate with the base station 104 and the base station 106 via the same RAT such as EUTRA or NR, or different RATs.
  • the base station 104 is an MeNB and the base station 106 is a SgNB
  • the UE 102 can be in EUTRA-NR DC (EN-DC) with the MeNB and the SgNB.
  • an MeNB or an SeNB is implemented as an ng-eNB rather than an eNB.
  • the base station 104 is a Master ng-eNB (Mng-eNB) and the base station 106 is a SgNB
  • the UE 102 can be in next generation (NG) EUTRA-NR DC (NGEN-DC) with the Mng-eNB and the SgNB.
  • NG next generation
  • NGEN-DC EUTRA-NR DC
  • the base station 104 is an MgNB and the base station 106 is an SgNB
  • the UE 102 may be in NR-NR DC (NR-DC) with the MgNB and the SgNB.
  • NR-DC NR-NR DC
  • the UE 102 may be in NR-EUTRA DC (NE-DC) with the MgNB and the Sng-eNB.
  • NE-DC NR-EUTRA DC
  • the base stations 104 and 106 operate as the source base station (S-BS) and a target base station (T-BS), respectively.
  • the UE 102 can operate in DC with the base station 104 and an additional base station (not shown in Fig. 1 A) for example prior to the handover.
  • the UE 102 can continue to operate in DC with the base station 106 and the additional base station or operate in single connectivity (SC) with the base station 106, after completing the handover.
  • the base stations 104 and 106 in this case operate as a source MN (S-MN) and a target MN (T-MN), respectively.
  • a core network (CN) 110 can be an evolved packet core (EPC) 111 or a fifthgeneration core (5GC) 160, both of which are depicted in Fig. 1 A.
  • the base station 104 can be an eNB supporting an SI interface for communicating with the EPC 111, an ng-eNB supporting an NG interface for communicating with the 5GC 160, or a gNB that supports an NR radio interface as well as an NG interface for communicating with the 5GC 160.
  • the base stations 104 and 106 can support an X2 or Xn interface.
  • the EPC 111 can include a Serving Gateway (SGW) 112, a Mobility Management Entity (MME) 114, and a Packet Data Network Gateway (PGW) 116.
  • SGW Serving Gateway
  • MME Mobility Management Entity
  • PGW Packet Data Network Gateway
  • the SGW 112 is generally configured to transfer user-plane packets related to audio calls, video calls, Internet traffic, etc.
  • MME Mobility Management Entity
  • PGW Packet Data Network Gateway
  • the SGW 112 is generally configured to transfer user-plane packets related to audio calls, video calls, Internet traffic, etc.
  • the MME 114 is configured to manage authentication, registration, paging, and other related functions.
  • the PGW 116 provides connectivity from the UE to one or more external packet data networks, e.g., an Internet network and/or an Internet Protocol (IP) Multimedia Subsystem (IMS) network.
  • IP Internet Protocol
  • IMS Internet Multimedia Subsystem
  • the 5GC 160 includes a User Plane Function (UPF) 162 and an Access and Mobility Management (AMF) 164, and/or Session Management Function (SMF) 166.
  • the UPF 162 is generally configured to transfer user-plane packets related to audio calls, video calls, Internet traffic, etc.
  • the AMF 164 is configured to manage authentication, registration, paging, and other related functions
  • the SMF 166 is configured to manage PDU sessions.
  • the base station 104 supports cell 124A, and the base station 106 supports a cell 126.
  • the cells 124A and 126 can partially overlap, so that the UE 102 can communicate in DC with the base station 104 and the base station 106, where one of the base stations 104 and 106 is an MN and the other is an SN.
  • the base station 104 can support additional cell(s) such as cells 124B and 124C, and the base station 106 can support additional cell(s) (not shown in Fig. 1 A).
  • the cells 124A, 124B and 124C can partially overlap, so that the UE 102 can communicate in carrier aggregation (CA) with the base station 104.
  • CA carrier aggregation
  • the base station 104 can operate the cells 124A, 124B and 124C via one or more transmit and receive points (TRPs). More particularly, when the UE 102 is in DC with the base station 104 and the base station 106, one of the base stations 104 and 106 operates as an MeNB, an Mng-eNB or an MgNB, and the other operates as an SgNB or an Sng-eNB.
  • TRPs transmit and receive points
  • the wireless communication network 100 can include any suitable number of base stations supporting NR cells and/or EUTRA cells. More particularly, the EPC 111 or the 5GC 160 can be connected to any suitable number of base stations supporting NR cells and/or EUTRA cells. Although the examples below refer specifically to specific CN types (EPC, 5GC) and RAT types (5GNR and EUTRA), in general the techniques of this disclosure also can apply to other suitable radio access and/or core network technologies such as sixth generation (6G) radio access and/or 6G core network or 5GNR-6G DC.
  • 6G sixth generation
  • the base station 104 is equipped with processing hardware 130 that can include one or more general-purpose processors (e.g., CPUs) and a non-transitory computer-readable memory storing instructions that the one or more general-purpose processors execute. Additionally or alternatively, the processing hardware 130 can include special-purpose processing units.
  • the processing hardware 130 can include a PHY controller (not shown) configured to transmit data and control signal on physical downlink (DL) channels and DL reference signals with one or more user devices (e.g. UE 102) via one or more cells (e.g., the cell(s) 124A, 124B and/or 124C) and/or one or more TRPs.
  • DL physical downlink
  • UE 102 user devices
  • cells e.g., the cell(s) 124A, 124B and/or 124C
  • the PHY controller is also configured to receive data and control signal on physical uplink (UL) channels and/or UL reference signals with the one or more user devices via one or more cells (e.g., the cell(s) 124A, 124B and/or 124C) and/or one or more TRPs.
  • the processing hardware 130 in an example implementation includes a MAC controller (not shown) configured to perform MAC functions with one or more user devices.
  • the MAC functions include a random access (RA) procedure, managing UL timing advance for the one or more user devices, and/or communicating UL/DL MAC PDUs with the one or more user devices.
  • the MAC functions include lower triggered mobility (LTM) related functions as described below.
  • the processing hardware 130 can further include an RRC controller (not shown) to implement procedures and messaging at the RRC sublayer of the protocol communication stack.
  • the RRC controller may be configured to support RRC messaging associated with handover procedures, and/or to support the necessary operations when the base station 104 operates as an MN relative to an SN or as an SN relative to an MN.
  • the base station 106 can include processing hardware 140 that is similar to processing hardware 130.
  • the UE 102 is equipped with processing hardware 150 that can 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 special-purpose processing units.
  • the PHY controller (not shown) is also configured to receive data and control signal on physical DL channels and/or DL reference signals with the base station 104 or 106 via one or more cells (e.g., the cell(s) 124A, 124B, 124C and/or 126) and/or one or more TRPs.
  • the PHY controller is also configured to transmit data and control signal on physical UL channels and/or UL reference signals with the base station 104 or 106 via one or more cells (e.g., the cell(s) 124A, 124B, 124C and/or 126) and/or one or more TRPs.
  • the processing hardware 150 in an example implementation includes a MAC controller (not shown) configured to perform MAC functions with base station 104 or 106.
  • the MAC functions includes a random access procedure, managing UL timing advance for the one or more user devices, and communicating UL/DL MAC PDUs with the base station 104 or 106.
  • the MAC functions includes LTM related functions as described below.
  • the processing hardware 150 can further include an RRC controller (not shown) to implement procedures and messaging at the RRC sublayer of the protocol communication stack.
  • the processing hardware 130 of the base station 104 can implement an LTM configuration controller 132 to support LTM configuration and coordination procedures discussed below, including MN procedures related to LTM configuration and coordination.
  • the processing hardware 140 of the base station 106 can implement an LTM configuration controller 142 to support LTM configuration and coordination procedures discussed below, including SN procedures related to LTM configuration and coordination.
  • the processing hardware 150 of the UE 102 can implement an LTM configuration controller 152 to support LTM configuration and coordination procedures discussed below, including UE procedures related to LTM configuration and coordination.
  • the LTM controllers 132, 142, and 152 can be implemented as respective sets of instructions executable by one or more processors, for example.
  • the UE 102 in DC can use a radio bearer (e.g., a DRB or an SRB) that at different times terminates at the MN 104 or the SN 106.
  • the UE 102 can apply one or more security keys when communicating on the radio bearer, in the uplink (UL) (from the UE 102 to a base station) and/or downlink (from a base station to the UE 102) direction.
  • a radio bearer e.g., a DRB or an SRB
  • the UE 102 can apply one or more security keys when communicating on the radio bearer, in the uplink (UL) (from the UE 102 to a base station) and/or downlink (from a base station to the UE 102) direction.
  • Fig. IB depicts an example distributed implementation of a base station such as the base station 104 or 106.
  • the base station in this implementation can include a centralized unit (CU) 172 and one or more distributed units (DUs) 174.
  • the CU 172 is equipped with processing hardware that can 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 special-purpose processing units.
  • the CU 172 is equipped with the processing hardware 130.
  • the CU 172 is equipped with the processing hardware 140.
  • the processing hardware 140 in an example implementation includes an SN RRC controller (not shown)configured to manage or control one or more RRC configurations and/or RRC procedures when the base station 106 operates as an SN.
  • the DU 174 is also equipped with processing hardware that can 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 special-purpose processing units.
  • the processing hardware in an example implementation includes a medium access control (MAC) controller configured to manage or control one or more MAC operations or procedures (e.g., a random access procedure) and a radio link control (RLC) controller configured to manage or control one or more RLC operations or procedures when the base station 106 operates as an MN or an SN.
  • the process hardware may include further a physical layer controller configured to manage or control one or more physical layer operations or procedures.
  • FIG. 2A illustrates, in a simplified manner, an example protocol stack 200 according to which the UE 102 can communicate with an eNB/ng-eNB or a gNB (e.g., one or more of the base stations 104, 106).
  • an eNB/ng-eNB or a gNB e.g., one or more of the base stations 104, 106.
  • a physical layer (PHY) 202A of EUTRA provides transport channels to the EUTRA MAC sublayer 204A, which in turn provides logical channels to the EUTRA RLC sublayer 206A.
  • the EUTRA RLC sublayer 206A in turn provides RLC channels to an EUTRA PDCP sublayer 208 and, in some cases, to an NR PDCP sublayer 210.
  • the NR PHY 202B provides transport channels to the NR MAC sublayer 204B, which in turn provides logical channels to the NR RLC sublayer 206B.
  • the NR RLC sublayer 206B in turn provides data transfer services to the NR PDCP sublayer 210.
  • the NR PDCP sublayer 210 in turn can provide data transfer services to Service Data Adaptation Protocol (SDAP) 212 or a radio resource control (RRC) sublayer (not shown in Fig. 2A).
  • SDAP Service Data Adaptation Protocol
  • RRC radio resource control
  • the UE 102 in some implementations, supports both the EUTRA and the NR stack as shown in Fig. 2A, to support handover between EUTRA and NR base stations and/or to support DC over EUTRA and NR interfaces. Further, as illustrated in Fig. 2A, the UE 102 can support layering of NR PDCP 210 over EUTRA RLC 206 A, and SDAP sublayer 212 over the NR PDCP sublayer 210.
  • the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 receive packets (e.g., from an Internet Protocol (IP) layer, layered directly or indirectly over the PDCP layer 208 or 210) that can be referred to as service data units (SDUs), and output packets (e.g., to the RLC layer 206A or 206B) that can be referred to as protocol data units (PDUs). Except where the difference between SDUs and PDUs is relevant, this disclosure for simplicity refers to both SDUs and PDUs as “packets.”
  • IP Internet Protocol
  • PDUs protocol data units
  • the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 can provide signaling radio bearers (SRBs) or RRC sublayer (not shown in Fig. 2 A) to exchange RRC messages or non-access-stratum (NAS) messages, for example.
  • SRBs signaling radio bearers
  • RRC sublayer not shown in Fig. 2 A
  • NAS non-access-stratum
  • the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 can provide Data Radio Bearers (DRBs) to support data exchange.
  • Data exchanged on the NR PDCP sublayer 210 can be SDAP PDUs, Internet Protocol (IP) packets or Ethernet packets.
  • IP Internet Protocol
  • Fig. 2B illustrates, in a simplified manner, an example protocol stack 250, which the UE 102 can communicate with a DU (e.g., DU 174) and a CU (e.g., CU 172).
  • the radio protocol stack 200 is functionally split as shown by the radio protocol stack 250 in Fig. 2B.
  • the CU at any of the base stations 104 or 106 can hold all the control and upper layer functionalities (e.g., RRC 214, SDAP 212, NR PDCP 210), while the lower layer operations (e.g., NR RLC 206B, NR MAC 204B, and NR PHY 202B) are delegated to the DU.
  • NR PDCP 210 provides SRBs to RRC 214
  • NR PDCP 210 provides DRBs to SDAP 212 and SRBs to RRC 214.
  • event 316 is similar to event 416 of Figs 4A and 4B, event 516 of Fig. 5 A, event 517 of Fig. 5B, event 616 of Fig. 6A, event 617 of Fig. 6B, event 716 of Fig. 7 A, and event 717 of Fig. 7B), with differences discussed below where appropriate.
  • event 316 is similar to event 416 of Figs 4A and 4B, event 516 of Fig. 5 A, event 517 of Fig. 5B, event 616 of Fig. 6A, event 617 of Fig. 6B, event 716 of Fig. 7 A, and event 717 of Fig. 7B), with differences discussed below where appropriate.
  • any of the alternative implementations discussed with respect to a particular event may apply to events labeled with similar reference numbers in other figures.
  • the base station 104 includes a CU 172 and a DU 174 and the DU 174 operates the cell 124 A.
  • the UE 102 initially communicates 302 with the DU 174 on the cell 124 A using a serving DU configuration, and communicates with the CU 172 via the DU 174, e.g., using a serving CU configuration.
  • the DU 174 is a serving DU that is communicating with the UE 102.
  • the UE 102 in carrier aggregation (CA) communicates with the DU 174 on the cell 124 A and other cell(s) (e.g., cell 124D not shown in Fig.
  • CA carrier aggregation
  • the DU 174 operates the other cell(s).
  • the UE 102 in communicates with the DU 174 on the cell 124A only.
  • the UE 102 communicates with the DU 174 on the cell 124A and/or other cell(s) via one or multiple TRPs.
  • the cell 124 A can be a PCell.
  • the other cell(s) include SCell(s) and/or additional cell(s) associated with the PCell or a SCell.
  • the cell 124A can be a SCell, and one of the other cell(s) is a PCell.
  • the rest includes SCell(s) and/or additional cell(s) associated with the PCell or a SCell.
  • the base station 104 can be the DU 174, the CU 172 or the DU 174 and CU 172.
  • the UE 102 can transmit UL PDUs and/or UL control signals to the base station 104 on the cell 124A and/or other cell(s) via one or multiple TRPs.
  • the UE 102 communicates UL PDUs and/or DL PDUs with the base station 104 via radio bearers which can include SRBs and/or DRB(s).
  • the base station 104 can configure the radio bearers to the UE 102.
  • UL control signals include UL control information, channel state information, hybrid automatic repeat request (HARQ) acknowledgements (ACKs), HARQ negative ACKs, scheduling request(s) and/or sounding reference signal(s).
  • HARQ hybrid automatic repeat request
  • ACKs hybrid automatic repeat request acknowledgements
  • HARQ negative ACKs scheduling request(s) and/or sounding reference signal(s).
  • the UE 102 can receive DL PDUs and/or DL control signals from the base station 104 on the cell 124A and/or other cell(s) via one or multiple TRPs.
  • the DL control signals include downlink control information (DCIs) and reference signals (e.g., synchronization signal block, channel state information reference signal(s) (CSI-RS(s)), and/or tracking reference signal(s)).
  • the base station 104 can transmit the DCIs on physical downlink control channel(s) (PDCCH(s)) monitored by the UE 102, on the cell 124A and/or other cell(s) via one or multiple TRPs.
  • PDCCH(s) physical downlink control channel(s)
  • the serving DU configuration includes physical layer configuration parameters, MAC configuration parameters, and/or RLC configuration parameters.
  • the DU 174 can transmit these configuration parameters to the CU 172.
  • the CU 172 generates one or more messages (e.g., RRC reconfiguration message(s)) including the configuration parameters and transmits the one or more messages to the UE 102 via the DU 174.
  • the DU 174 transmits the configuration parameters to the UE 102 directly.
  • the serving DU configuration is CellGroupConfig IE defined in 3GPP specification 38.331. In other implementations, the serving DU configuration includes configuration parameters in the CellGroupConfig IE.
  • the serving CU configuration includes PDCP configuration parameters, measurement configuration parameters, and/or radio bearer configuration parameters.
  • the serving CU configuration includes a MeasConfig IE and/or a RadioBearerConfig IE defined in 3GPP specification 38.331 or includes configuration parameters in the MeasConfig IE and/or RadioBearerConfig IE.
  • the serving DU configuration includes a CSI-MeasConfig IE or configuration parameters for channel state information (CSI) measurement and reporting.
  • the serving CU configuration includes a CSI-MeasConfig IE or configuration parameters for CSI measurement and reporting.
  • the UE 102 receives the serving CU configuration or the configuration parameters in the serving CU configuration from the CU 172 via the DU 174. In other implementations, the UE 102 receives a portion of the serving CU configuration and/or a portion of the serving DU configuration from a base station other than the base station 104 and the remaining portion of these configuration parameters from the base station 104.
  • the UE 102 While communicating with the base station 104, the UE 102 transmits 304 at least one measurement report to the DU 174.
  • the at least one measurement report includes Layer 1 (LI) measurement report(s) and/or Layer 3 (L3) measurement report(s) for at least one serving cell of the UE 102 and/or at least one nonserving cell.
  • the DU 174 transmits 306 a DU-to- CU message including the L3 measurement report to the CU 172.
  • the DU-to-CU message(s) of the event 306 is/are Fl application protocol (F1AP) message(s) (e.g., UL RRC Message Transfer message(s)).
  • Fl application protocol F1AP
  • the DU 174 does not transmit or refrains from transmitting the LI measurement report(s) to the CU 172.
  • the at least one serving cell includes the cell 124A and/or other cell(s), and the at least one nonserving cell includes the cell 124B and/or cell 124C.
  • the serving DU configuration or the serving CU configuration includes at least one measurement configuration.
  • the UE 102 receives one or more RRC messages (e.g., RRCReconfiguration message(s)) including the at least one measurement configuration from the CU 172 via the DU 174 in the event 302.
  • the UE 102 performs measurements and transmits 304 the at least one measurement report to the DU 174.
  • the at least one measurement configuration includes L3 measurement configuration(s) (e.g., MeasConfig IE(s)) and/or LI measurement configuration(s).
  • the LI measurement configuration(s) e.g., CSI-MeasConfig IE(s)
  • the LI measurement resource configuration(s) can configure reference signal(s) and/or resources of the reference signal(s) for the UE 102 to measure and obtain LI measurement results.
  • the reference signal(s) includes CSLRS(s) and/or Synchronization Signal (SS)/ Physical Broadcast Channel (PBCH) Resource Block(s) (SSB(s)).
  • the LI measurement resource configuration(s) is/are CSI-ResourceConfig IE(s).
  • the LI measurement reporting configuration(s) configures way(s) the UE 102 uses to transmit LI measurement results/reports.
  • the LI measurement report configuration(s) is/are CSI- ReportConfig IE(s).
  • the UE 102 transmits the L3 measurement report(s) to the CU 172 via the DU 174 in accordance with the L3 measurement configuration(s).
  • the UE 102 transmits the LI measurement report(s) to the DU 174 in accordance with the LI measurement configuration(s) or LI measurement reporting configuration(s). In one implementations, the DU 174 does not transmit the LI measurement report(s) to the CU 172.
  • the LI measurement configuration(s) are new RRC IE(s) defined in 3GPP specification 38.331 vl8.0.0 and/or later version for a lower layer triggered mobility (LTM).
  • the LI measurement resource configuration(s) are new RRC IE(s) defined in 3GPP specification 38.331 vl8.0.0 and/or later version for the LTM.
  • the LI measurement reporting configuration(s) are new RRC IE(s) defined in 3GPP specification 38.331 vl8.0.0 and/or later version for the LTM.
  • each of the LI measurement reporting configuration(s) can include a trigger event configuration configuring a trigger event to trigger the UE 102 to transmit a LI measurement report. If the UE 102 detects the trigger event, the UE 102 transmits a LI measurement report to the DU 174.
  • each of the LI measurement report(s) can include at least one LI measurement result.
  • the at least LI measurement result includes at least one LI -reference signal received power (Ll-RSRP) value and/or at least one LI- Signal to Interference Noise Ratio (Ll-SINR) value.
  • Ll-RSRP LI -reference signal received power
  • Ll-SINR LI- Signal to Interference Noise Ratio
  • the UE 102 transmits a PUSCH transmission including the LI measurement report to the DU 174. That is, the UE 102 transmits the each of the LI measurement report(s) on a PUSCH to the DU 174. In yet other implementations, the UE 102 transmits a portion of the LI measurement report(s) on PUCCH(s) and the rest of the LI measurement report(s) on physical UL shared channel(s) (PUSCH(s)) to the DU 174.
  • each of the LI measurement report(s) is a part of CSI (i.e., a CSI component) or CSI.
  • the UE 102 can include other CSI component(s) in (each of) the PUCCH transmission(s) and/or PUSCH transmission(s) described above.
  • the other CSI component(s) include such as a channel quality indicator (CQI), a Precoding Matrix Indicator (PMI), a CSLRS Resource Indicator (CRI), a SSB Resource Indicator (SSBRI), a Layer Indicator (LI), and/or a Rank Indicator (RI).
  • CQI channel quality indicator
  • PMI Precoding Matrix Indicator
  • SSBRI SSB Resource Indicator
  • LI Layer Indicator
  • RI Rank Indicator
  • the UE 102 does not transmit the LI measurement report(s) in format of RRC message(s) to the DU 174.
  • each of the L3 measurement report(s) can include at least one L3 measurement result.
  • the at least one L3 measurement result includes at least one RSRP (value) and/or at least one SINR (value).
  • the UE 102 transmits each of the L3 measurement report(s) on a PUSCH to the CU 172 via the DU 174.
  • each of the L3 measurement report(s) can be a RRC message (e.g., MeasurementReport message).
  • each of the L3 measurement configuration(s) includes a particular measurement identity (e.g., measld) and each of the L3 measurement report(s) includes a particular measurement identity in a particular L3 measurement configuration.
  • the CU 172 receives a L3 measurement report including a measurement identity and a L3 measurement result from the UE 102 via the DU 174, the CU 172 can determine that the L3 measurement report is associated to a L3 measurement configuration identified by the measurement identity.
  • the UE 102 transmits a MAC control element (CE) including the measurement report to the DU 174 in the event 304.
  • a MAC control element CE
  • the UE 102 generate one or more MAC PDUs each including one or more of the MAC CE(s) to the DU 174 in the event 304.
  • the UE 102 performs measurements on one or more reference signals in accordance with the at least one measurement configuration.
  • the one or more reference signals can include one or more Synchronization Signal (SS)/ Physical Broadcast Channel (PBCH) Resource Blocks (SSBs) and/or one or more CSI-RSs.
  • the UE 102 obtains the at least one LI measurement result and/or at least one L3 measurement result from the measurements.
  • the DU 174 transmits the one or more reference signals on the cell 124A and other cell(s) (e.g., the cell 124B, the cell 124C and/or cell(s) not shown in Fig. 1 A).
  • the base station 104 determines to prepare a first cell (e.g., the cell 124B) for LTM for the UE 102.
  • the base station 104 determines to prepare the first cell for the UE 102 because the at least one measurement report indicates that the first cell could be used by the base station 104 to communicate with the UE 102.
  • the base station 104 determines to prepare the first cell for the UE 102 because the at least one measurement report indicates that the first cell qualifies to be a candidate cell that could be used for communication with the UE 102. In some implementations, if the L3 measurement report(s) indicates that signal strength and/or quality of the first cell is above a first predetermined threshold, is better than strength and/or quality of the cell 124A, and/or is better than strength and/or quality of the cell 124 A by a first predetermined threshold, the CU 172 determines to prepare the first cell for the UE 102.
  • the DU 174 determines to prepare the first cell for the UE 102.
  • the base station 104 determines to prepare the first cell for the UE 102 regardless of whether a measure report is received from the UE 102 or not.
  • the CU 172 transmits 308 a first CU-to-DU message to the DU 174 to prepare the first cell for the UE 102.
  • the CU 172 includes a cell identity (ID) 1 of the first cell in the first CU-to-DU message to request the DU 174 to prepare the first cell for LTM for the UE 102.
  • the cell ID 1 is cell global identity (CGI).
  • the cell ID is a portion of the CGI.
  • the cell ID is a physical cell ID (PCI).
  • the CU 172 includes an LTM indicator in the first CU-to-DU message to indicate the DU 174 to prepare the first cell for LTM.
  • the LTM indicator is an LTM Information to be Setup IE o LTM Information to be Modification IE.
  • the DU 174 In response to the first CU-to-DU message, the DU 174 generates a first LTM DU configuration (referred to herein after as LTM DU configuration 1) for the UE 102, which configures the first cell for LTM.
  • the DU 174 transmits 310 a first DU-to-CU message including the LTM DU configuration 1 to the CU 172 in response to the first CU-to-DU message.
  • the DU 174 can include the cell ID 1 together with the LTM DU configuration 1 in an IE of the first DU-to-CU message to indicate that the LTM DU configuration 1 is associated with the first cell (i.e., the cell ID 1).
  • the DU 174 determines to prepare the first cell, the DU 174 initiates transmission of the first DU-to- CU message to the CU 172 instead of in response to a CU-to-DU message received from the CU 172.
  • the DU 174 includes, in the first DU-to-CU message, the cell ID of the first cell associated with the LTM DU configuration 1 to indicate that the LTM DU configuration 1 is configured for or associated with the first cell.
  • the CU 172 identifies the LTM DU configuration 1 is configured for or associated with the first cell.
  • the CU 172 can include additional cell ID(s) (e.g., cell ID(s) 2, . . ., N) in the first CU-to-DU message to prepare additional cell(s) (e.g., cell(s) 2, . .
  • the DU 174 includes additional LTM DU configuration(s) (e.g., LTM DU configuration(s) 2, . . . , N) each configuring a particular cell of the additional cell(s), as described below.
  • the DU 174 includes, in the first DU-to-CU message, the additional cell ID(s) respectively associated with the additional LTM DU configuration(s) to indicate that which LTM DU configuration is associated to which cell (ID).
  • the cell(s) 1 and/or 2, . . . , N are candidate cell(s).
  • the CU 172 does not include a (reference) LTM DU configuration in the first CU-to-DU message.
  • the DU 174 generates a reference LTM DU configuration, generates the LTM DU configuration(s) 1 and/or 2, . . ., N (i.e., nonreference LTM DU configuration(s)) based on the reference LTM DU configuration, and includes the reference LTM DU configuration in the first DU-to-CU message.
  • the CU 172 includes a reference LTM DU configuration in the first CU-to- DU message. In such cases, the DU 174 generates the LTM DU configuration(s) 1, and/or 2, . .
  • the CU 172 includes a reference LTM DU configuration (e.g., a first reference LTM DU configuration) in the first CU-to-DU message.
  • the DU 174 generates a reference LTM DU configuration (e.g., a second reference LTM DU configuration) replacing the first reference LTM DU configuration, generates the LTM DU configuration(s) 1 and/or 2, . . ., N based on the second reference LTM DU configuration, and includes the second reference LTM DU configuration in the first DU-to-CU message.
  • the reference LTM DU configuration includes physical layer configuration parameters, MAC configuration parameters, and/or RLC configuration parameters.
  • the reference LTM DU configuration is CellGroupConfig IE defined in 3 GPP specification 38.331.
  • the reference LTM DU configuration includes configuration parameters in the CellGroupConfig IE.
  • the reference LTM DU configuration includes a CSI- MeasConfig IE or configuration parameters for channel state information (CSI) measurement and/or reporting.
  • CSI channel state information
  • the reference LTM DU configuration is different from the serving DU configuration.
  • a portion of the reference LTM DU configuration is the same as a portion of the serving DU configuration and the rest of the reference LTM DU configuration is different from the rest of the serving DU configuration.
  • the reference LTM DU configuration is the same as the serving DU configuration.
  • the CU 172 After receiving the first DU-to-CU message, the CU 172 generates a RRC reconfiguration message (e.g., an RRCReconfiguration message) including the LTM DU configuration 1 and transmits 316 a second CU-to-DU message including the RRC reconfiguration message to the DU 174.
  • a RRC reconfiguration message e.g., an RRCReconfiguration message
  • the CU 172 includes the reference LTM DU configuration in the RRC reconfiguration message 316.
  • the CU 172 does not include a/the reference LTM DU configuration in the RRC reconfiguration message 316.
  • the CU 172 if the CU 172 transmits the reference LTM DU configuration to the UE 102 during the event 302, the CU 172 does not include the reference LTM DU configuration in the RRC reconfiguration message 316. In other implementations, if the CU 172 receives the reference LTM DU configuration from the DU 174, the CU 172 includes the LTM DU configuration in the RRC reconfiguration message 316. Otherwise, if the CU 172 does not receive a reference LTM DU configuration from the DU 174, the CU 172 does not include the reference LTM DU configuration in the RRC reconfiguration message 316.
  • the CU 172 includes the LTM DU configuration 1 and/or the LTM CU configuration 1 in a first container (e.g., a field/IE) and includes the first container (e.g., LTM configuration 1) in the RRC reconfiguration message of the events 316 and 318. In such cases, the CU 172 generates the first container.
  • the first container is to indicate the UE 102 not to apply the LTM DU configuration 1 and/or the LTM CU configuration 1 immediately.
  • the UE 102 receives a RRC reconfiguration message (e.g., the RRC reconfiguration message of the event 318) including a configuration (e.g., the LTM DU configuration 1 or the LTM configuration 1).
  • the UE 102 refrains from immediately applying the configuration. Otherwise, if the configuration is not included in the first container, the UE 102 can apply the configuration immediately.
  • the first container includes or is a first addition or modification list (e.g., Itm- ConfigToAddModList field, Itm-CandidateToAddModList field, or Itm- CandidateConfigToAddModList field).
  • the CU 172 includes the LTM DU configuration 1 and/or the LTM CU configuration 1 in a first element (referred to herein after as element 1) of the first addition or modification list.
  • the CU 172 generates an RRC message (e.g., RRCRecconfiguration message) including the LTM DU configuration 1 and/or the LTM CU configuration 1, and includes the RRC message in the element 1.
  • the element 1 is an addition or modification IE (e.g., LTM- ConfigToAddMod IE, LTM-Candidate IE, LTM-CandidateToAddMod IE or LTM- CandidateConfigToAddMod IE).
  • the UE 102 can store the first addition or modification list, e.g., in a variable in its random access memory (RAM).
  • the DU 174 generates the first container and includes the first container in the first DU-to-CU message. In yet other alternative implementations, the DU 174 generates the element 1 and includes the element 1 in the first DU-to-CU message.
  • the CU 172 includes an LTM CU configuration 1 in the RRC reconfiguration message 316, the first container or the element 1, where the LTM CU configuration 1 associated with the LTM DU configuration 1.
  • the CU 172 can include the LTM CU configuration 1 and the LTM DU configuration in the element 1.
  • the CU 172 includes LTM CU configuration(s) 2, . . ., N in the RRC reconfiguration message 316 or the second container, where the LTM CU configuration(s) 2, . . . , N associated with the LTM DU configuration(s) 2, . . . , N, respectively.
  • the CU 172 can include the LTM CU configured on(s) 2, . . . , N and the LTM DU configured on(s) in the element(s) 2, . . . , N, respectively.
  • the CU 172 includes, in the element(s) 2, . . ., N, the LTM CU configured on(s) 2, . . . , N associated with the LTM DU configured on(s) 2, . . . , N, respectively.
  • the CU 172 does not include, in the RRC reconfiguration message 316, LTM CU configured on(s) for some or all of the LTM DU configuration 1 and/or LTM DU configuration(s) 2, . . . , N.
  • the DU 174 transmits 318 the RRC reconfiguration message to the UE 102.
  • the UE 102 transmits 320 a RRC reconfiguration complete message (e.g., an RRCReconfigurationComplete message) to the DU 174, which in turn transmits 322 a second DU-to-CU message including the RRC reconfiguration complete message to the CU 172.
  • the CU 172 performs security protection (e.g., integrity protection and/or encryption) on the RRC reconfiguration message.
  • the CU 172 generates a message authentication code for integrity (MAC-I) for the RRC reconfiguration message, encrypts the RRC reconfiguration message and the MAC-I to obtain an encrypted RRC reconfiguration message and an encrypted MAC-I, and transmits a PDCP PDU including the encrypted RRC reconfiguration message and encrypted MAC-I to the UE 102 via the DU 174 in the events 316 and 318.
  • MAC-I message authentication code for integrity
  • the UE 102 If the UE 102 verifies the MAC-I is invalid, the UE 102 discards or ignores the RRC reconfiguration message. In some implementations, the UE 102 can perform a RRC connection reestablishment procedure in response to the invalid MAC-I. Otherwise, if the UE 102 verifies the MAC-I is valid, the UE 102 can process the RRC reconfiguration. The UE 102 refrains from applying (i.e., executing) the LTM DU configuration 1 until receiving an LTM command activating the LTM DU configuration 1 as described for events 330, 350.
  • the events 308 (optional) and 310 are collectively referred to in Fig. 3 as an LTM preparation procedure 390.
  • the events 316, 318, 320, 322 are collectively referred to in Fig. 3 as an LTM configuration delivery procedure 394.
  • the first CU-to-DU message is a UE Context Modification Request message
  • the first DU-to-CU message is a UE Context Modification Response message or UE Context Modification Required message.
  • the CU 172 can transmit a UE Context Modification Confirm message to the DU 174 in response to UE Context Modification Required message.
  • the second CU-to-DU message is DL RRC Message Transfer message.
  • the second CU-to-DU message is a UE Context Modification Request message and the DU 174 can transmit a second DU-to-CU message (e.g., UE Context Modification Response message) to the CU 172 in response to the second CU-to-DU message.
  • a second DU-to-CU message e.g., UE Context Modification Response message
  • the CU 172 includes a reference LTM CU configuration in the RRC reconfiguration message 316 or the first container.
  • the CU 172 generates the LTM CU configuration 1 (i.e., non-reference LTM CU configuration) as a delta configuration to augment the reference LTM CU configuration.
  • the CU 172 can generate some or all of the LTM CU configuration(s) 2, . . ., N as delta configuration(s) to augment the reference LTM CU configuration.
  • the CU 172 includes the reference LTM CU configuration and does not include a non-reference LTM CU configuration.
  • the CU 172 includes the reference LTM CU configuration and/or the reference LTM DU configuration in an additional container (e.g., reference LTM configuration) and include the additional container in the RRC reconfiguration message 316.
  • the reference LTM CU configuration is different from the serving CU configuration. In some implementations, a portion of the reference LTM CU configuration is the same as a portion of the serving CU configuration and the rest of the reference LTM CU configuration is different from the rest of the serving CU configuration. In yet other implementations, the reference LTM CU configuration is the same as the serving LTM CU configuration.
  • the CU 172 includes, in the RRC reconfiguration message, a first LTM ID (referred to herein after as ID 1) for identifying the LTM DU configuration 1 or the element 1.
  • ID 1 a first LTM ID
  • the CU 172 includes the ID 1 in the first container or element 1.
  • the CU 172 assigns the ID 1.
  • the CU 172 can transmit the ID 1 to the DU 174, and the DU 174 associates the ID 1 with the LTM DU configuration 1 and/or the cell ID 1.
  • the CU 172 includes the ID 1 in the first CU-to-DU message.
  • the CU 172 transmits 312 a third CU-to-DU message including the ID 1 to the DU 174 instead of including the ID 1 in the first CU-to-DU message.
  • the CU 172 in the third CU-to-DU message, can include the LTM DU configuration 1 and the ID 1 and indicate the association between the ID 1 and LTM DU configuration 1.
  • the DU 174 can directly associate the ID 1 with the LTM DU configuration 1.
  • the CU 172 in the third CU-to-DU message, can include the cell ID 1 and the ID 1 (i.e., the first LTM ID) and indicate the association between the cell ID 1 and the ID 1.
  • the DU 174 can associate the ID 1 with the LTM DU configuration 1, based on the association between the cell ID 1 and the ID 1 and the association between the cell ID 1 and the LTM DU configuration 1.
  • the CU 172 in the third CU-to-DU message, can include the LTM DU configuration 1, the cell ID 1 and/or the ID 1 and indicate the association between the ID 1, LTM DU configuration 1 and/or the cell ID 1.
  • the DU 174 can transmit 314 a third DU-to-CU message to the CU 172 in response to the third CU-to-DU message.
  • the third CU-to-DU message and third DU-to-CU message are UE Context Modification Request message and UE Context Modification Response message.
  • the events 312 (optional) and 314 (optional) are collectively referred to in Fig. 3 as an LTM ID assignment procedure 392.
  • the CU 172 can include the ID 1, the cell ID 1 and/or the LTM DU configuration 1 in the second CU-to-DU message as described above.
  • the third CU-to-DU message can be omitted.
  • the DU 174 can include the ID 1 in the LTM DU configuration 1, first container or element 1. Alternatively, the DU 174 does not include the ID 1 in the LTM DU configuration 1, first container and/or element 1.
  • the CU 172 includes the reference LTM DU configuration in the first container.
  • the CU 172 includes the reference LTM DU configuration in a field of the first container, different from a field of the first container including the LTM DU configuration 1.
  • the CU 172 includes the reference LTM DU configuration in the RRC reconfiguration message 316 and outside the first container.
  • the CU 172 generates a third container (e.g., a field/IE) to include the first container and the reference LTM DU configuration and includes the third container in the RRC reconfiguration message 316.
  • the DU 174 includes the reference LTM DU configuration in the first container.
  • the DU 174 includes the reference LTM DU configuration in a field of the first container, different from a field of the first container including the LTM DU configuration 1.
  • the DU 174 generates a fourth container (e.g., a field/IE) to include the first container and the reference LTM DU configuration and includes the fourth container in the first DU-to-CU message 310.
  • the CU 172 includes the fourth container in the RRC reconfiguration message 316.
  • the CU 172 retrieves the reference LTM DU configuration and the LTM DU configuration 1 from the fourth container and includes the reference LTM DU configuration and the LTM DU configuration 1 as described above.
  • neither the CU 172 nor the DU 174 assign an ID to identify the reference LTM DU configuration. In some implementations, neither the CU 172 nor the DU 174 assign an ID to identify the reference LTM CU configuration.
  • the LTM DU configuration 1 includes a plurality of configuration parameters for the UE 102 to communicate with the DU 174 on the first cell.
  • the plurality of 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(s)).
  • the plurality of configuration parameters include a special cell configuration (e.g., SpCellConfig E) and/or one or more SCell configurations (e.g., SCellConfig IE(s)).
  • the LTM DU configuration 1 is CellGroupConfig ⁇ E defined in 3GPP specification 38.331. In other implementations, the LTM DU configuration 1 includes configuration parameters in the CellGroupConfig IE.
  • the LTM CU configuration 1 includes PDCP configuration parameters, measurement configuration parameters, and/or radio bearer configuration parameters.
  • the LTM CU configuration 1 includes a MeasConfig IE and/or a RadioBearerConfig IE defined in 3GPP specification 38.331 or includes configuration parameters in the MeasConfig IE and/or RadioBearerConfig IE.
  • the LTM DU configuration 1 includes LI measurement configuration 1 (e.g., a CSI-MeasConfig IE) and/or at least one configuration indicator (TCI) state configuration.
  • the LTM CU configuration 1 includes the LI measurement configuration and/or the TCI state configuration(s) 1.
  • the LI measurement configuration includes at least one reference signal (RS) resource configuration 1 and/or at least one report configuration 1.
  • the RS resource configuration(s) 1 configures one or more RSs or one or more RS resources associated with the cell 1.
  • the RS(s) includes SSB(s) and/or CSI-RS(s).
  • the RS resource(s) includes SSB resource(s) and/or CSI-RS resource(s).
  • each of the RS resource configuration(s) 1 includes a RS resource configuration ID.
  • the RS resource configuration(s) 1 is/are (similar to) CSI-ResourceConfig lPfi).
  • the report configuration(s) 1 configures one or more UL resources (e.g., PUCCH resources or PUSCH resources) on the cell 1 for the UE 102 to transmit measurement results.
  • each of the report configuration(s) 1 includes one or more RS resource configuration IDs identifying one or more RS resource configurations included in the RS resource configuration(s) 1.
  • each of the TCI state configuration(s) 1 configures a TCI state that associates one or two DL RSs with a corresponding quasi -colocation (QCL) type. The DL RS(s) are associated with the cell 1.
  • the DU 174 includes the LI measurement configuration 1 and/or the TCI state configuration(s) 1 in a serving DU configuration 1 (e.g., non-LTM DU configuration).
  • the DU 174 includes the serving DU configuration in the first DU-to-CU message.
  • the DU 174 transmits an additional DU-to-CU message including the serving DU configuration to the CU 172.
  • the additional DU-to-CU message is a UE Context Modification Required message.
  • the CU 172 includes the serving DU configuration 1 in the RRC reconfiguration message 316, 318.
  • the CU 172 transmits another RRC reconfiguration message including the serving DU configuration to the UE 102 via the DU 174.
  • the DU 174 includes a random access configuration in the LTM DU configuration 1. In other implementations, the DU 174 does not include a random access configuration in the LTM DU configuration 1. In some implementations, if the cell 124 A and first cell are not synchronized, the DU 174 determines to include the random access configuration in the LTM DU configuration 1. Otherwise, if the cell 124A and first cell are synchronized, the DU 174 determines to not include the random access configuration in the LTM DU configuration 1. In other implementations, if the DU 174 determines that the UE 102 has not synchronized in UL with the first cell, the DU 174 determines to include the random access configuration in the LTM DU configuration 1.
  • the DU 174 determines to not include the random access configuration in the LTM DU configuration 1. If the LTM DU configuration 1 includes the random access configuration, the UE 102 performs the random access procedure in the event 332 in accordance with the random access configuration, as described below. Otherwise, if the LTM DU configuration 1 does not include the random access configuration or indicates the UE 102 to skip a random access procedure in LTM, the UE 102 skips or refrains from performing the random access procedure of the event 332 in response to the LTM DU configuration 1 excluding the random access configuration.
  • the DU 174 includes random access configuration parameters in the LTM DU configuration 1 and/or the reference LTM DU configuration regardless of whether the cell 124 A and first cell are synchronized or not.
  • the UE 102 performs the random access procedure in the event 332 in accordance with the random access configuration parameters, as described below.
  • the random access configuration parameters configure physical random access channel (PRACH) resources, an association between SSB and PRACH resources, and/or one or more PRACH occasions.
  • PRACH physical random access channel
  • the DU 174 determines to include, in the LTM DU configuration 1, a first indication configuring the UE 102 not to perform a random access procedure on the first cell. Otherwise, if the cell 124 A and first cell are not synchronized, the DU 174 determines to not include the first indication in the LTM DU configuration 1. In other implementations, if the DU 174 determines that the UE 102 has synchronized in UL with the first cell, the DU 174 determines to include the first indication in the LTM DU configuration 1.
  • the DU 174 determines to not include the first indication in the LTM DU configuration 1. If the LTM DU configuration 1 includes the first indication, the UE 102 skips or refrains from performing the random access procedure of the event 332 in accordance with or in response to the first indication. Otherwise, if the LTM DU configuration 1 does not include the first indication, the UE 102 performs the random access procedure in accordance with the random access configuration in the event 332, in response to the LTM DU configuration 1 excluding the first indication, as described below.
  • the DU 174 includes a reconfiguration with sync configuration (e.g., ReconfigurationWithSync IE) in the LTM DU configuration 1 or special cell configuration. In other implementations, the DU 174 does not include a reconfiguration with sync configuration (e.g., ReconfigurationWithSync IE) in the LTM DU configuration 1 or special cell configuration. In some implementations, the DU 174 includes an LTM cell switch information in the first LTM DU configuration 1. In some implementations, the DU 174 includes the random access configuration (parameters) in the LTM cell switch information (e.g., Itm-CellSw itchinfo field or LTM-CellSw itchinfo IE).
  • a reconfiguration with sync configuration e.g., ReconfigurationWithSync IE
  • the DU 174 does not include a reconfiguration with sync configuration (e.g., ReconfigurationWithSync IE) in the LTM DU configuration 1 or special cell configuration.
  • the DU 174 includes an LTM cell switch
  • the DU 174 determines to include the reconfiguration with sync configuration in the LTM DU configuration 1. Otherwise, if the cell 124A and first cell are synchronized, the DU 174 determines to not include the reconfiguration with sync configuration in the LTM DU configuration 1. In other implementations, if the DU 174 determines that the UE 102 has not synchronized in UL with the first cell, the DU 174 determines to include the reconfiguration with sync configuration in the LTM DU configuration 1.
  • the DU 174 determines to not include the reconfiguration with sync configuration in the LTM DU configuration 1.
  • the UE 102 performs the random access procedure in the event 332 as described below, in response to or in accordance with the reconfiguration with sync configuration. Otherwise, if the LTM DU configuration 1 does not include the reconfiguration with sync configuration, the UE 102 skips or refrains from performing the random access procedure of the event 332.
  • the DU 174 includes a cell ID (i.e., cell ID 1) of cell 1 (i.e., the first cell) in the LTM DU configuration 1.
  • the cell ID 1 can be a PCI.
  • the cell ID 1 is a CGI.
  • the cell ID 1 included in the LTM DU configuration l is a PCI, while the cell ID 1 included in the first CU-to-DU message is a CGI.
  • the LTM DU configuration 1 includes a cell index 1 indexing the cell ID 1 or the first cell.
  • the cell index 1 is not a cell ID.
  • the cell index takes fewer bits than the cell ID.
  • the CU 172 sets the cell index 1 to a value and includes the cell index 1 in the first CU-to-DU message of the event 308.
  • the base station 104 determines to prepare additional cell(s) (i.e., cell(s) 2, . . ., N) of the base station 104 for LTM for the UE 102.
  • the base station 104 determines to prepare the additional cell(s) for LTM for the UE 102 because the at least one measurement report indicates that the additional cell(s) could be used by the base station 104 to communicate with the UE 102.
  • the additional cell(s) can include the cell 124C and/or cell(s) other than the cells 124A, 124B and 124C.
  • the CU 172 determines to prepare the particular cell for LTM for the UE 102.
  • the DU 174 determines to prepare the particular cell for LTM for the UE 102.
  • the respective predetermined threshold(s) for the additional cells can be different from the first predetermined threshold. In another implementation, the respective predetermined threshold(s) for the additional cell(s) can be the same as the first predetermined threshold. In some implementations, the respective predetermined thresholds for the additional cells can be the same or different. Alternatively, the base station 104 determines to prepare the additional cell(s) for the UE 102 regardless of whether a measurement report is received from the UE 102 or not.
  • the CU 172 determines to prepare the additional cell(s)
  • the CU 172 initiates and performs at least one additional LTM preparation procedure (LTM preparation procedure(s)) with the DU 174 to prepare the additional cell(s) for LTM, where each of the LTM preparation procedure(s) is similar to the procedure 390.
  • the DU 174 determines to prepare the additional cell(s)
  • the DU 174 initiates and performs at least one additional LTM preparation procedure (LTM preparation procedure(s)) with the CU 172 to prepare the additional cell(s) for LTM, where each of the LTM preparation procedure(s) is similar to the procedure 390.
  • the CU 172 and DU 174 perform LTM preparation procedure(s) 2, . . . , N to prepare the cell(s) 2, . . . , N, respectively, similar to the procedure 390.
  • the CU 172 can include the cell ID(s) 2, . . . , N in CU-to-DU message(s) 2, . . . , N in the LTM preparation procedure(s) 2, . . . , N, respectively, similar to the first CU-to-DU message.
  • the DU 174 In the LTM preparation procedure(s) 2, . . . , N, the DU 174 generates LTM DU configuration(s) 2, . . .
  • N configuring the cell(s) 2, . . . , N and includes the LTM DU configured on(s) 2, . . ., N in DU-to-CU message(s) 2, .., N, respectively, as described for the LTM DU configuration 1.
  • the DU 174 receives the CU-to-DU message(s) 2, . . . , N
  • the DU-to-CU message(s) 2, . . . , N responds to the CU-to-DU message(s) 2, . . . , N, respectively .
  • “N” is an integer and larger than one.
  • “N” is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 14, 15 or 16.
  • the CU 172 and DU 174 performs a single LTM preparation procedure (i.e., the LTM preparation procedure 390) to prepare the cell(s) 1, 2, . . ., N.
  • the DU 174 includes the LTM DU configured on(s) 1, 2, . . ., N for the cell(s) 1, 2, . . . , N, respectively in the first DU-to-CU message.
  • the DU 174 can include the cell ID(s) 1, 2, . . ., N respectively associated with the LTM DU configured on(s) 1, 2, . . .
  • the CU 172 determines to perform the LTM preparation procedure 390, the CU 172 includes the cell ID(s) 1, 2, . . ., N in the first CU-to-DU message to request the DU 174 to prepare the cell(s) 1, 2, ..., N, respectively, for LTM.
  • the CU 172 can include the LTM DU configured on(s) 2, . . ., N in the first container.
  • the CU 172 can include the LTM DU configured on(s) 2, . . ., N in element(s) 2, . . . , N, respectively, and includes the element(s) 2, . . . , N in the first container.
  • the CU 172 includes, in the RRC reconfiguration message, LTM ID(s) (i.e., ID(s) 2, . . .
  • the CU 172 includes the ID(s) 2, . . ., N in the first container.
  • the CU 172 can include the ID(s) 2, . . ., N and LTM DU configuration(s) 2, . . . , N in the element(s) 2, . . . , N in the first addition or modification list.
  • the CU 172 assigns the ID(s) 2, . . . , N for the LTM DU configured on(s) 2, . . ., N, respectively.
  • the CU 172 receives the ID(s) 2, . . ., N from the DU 174 in the first DU-to-CU message of the procedure 390.
  • the CU 172 receives from the DU 174 the ID(s) 2, . . ., N in the DU- to-CU message(s) 2, . . . , N of the LTM preparation procedure(s) 2, . . . , N, respectively.
  • the CU 172 can perform an LTM ID assignment procedure with the DU 174 for each of the LTM DU configured on(s) 2, . . ., N, similar to the procedure 392.
  • the CU 172 can include the ID(s) 2, . . ., N and the LTM DU configuration(s) 2, . . ., N in the third CU-to-DU message and indicate the association between the ID(s) 2, . . . , N and the LTM DU configured on(s) 2, . . . , N, respectively.
  • the DU 174 can associate the LTM DU configured on(s) 2, . . .
  • the CU 172 can include the cell ID(s) 2, . . . , N and the ID(s) 2, . . . , N in the third CU-to-DU message and indicate the association between the cell ID(s) 2, . . . , N and the ID(s) 2, . . . , N, respectively.
  • the DU 174 can associate the LTM DU configured on(s) 2, . . . , N with the ID(s) 2, . . . , N, respectively, based on the association between the cell ID(s) 2, . . .
  • the CU 172 can include the ID(s) 2, . . ., N, the cell ID(s) 2, . . . , N and/or the LTM DU configured on(s) 2, . . . , N in the second CU-to-DU message as described above.
  • the third CU-to-DU message can be omitted.
  • the CU 172 can include the ID(s) 2, . .
  • the DU 174 includes the ID(s) 2, . . N in the LTM DU configuration(s) 2, . . . , N.
  • the CU 172 does not include the ID(s) 2, . . . , N in the RRC reconfiguration message, first container and/or element(s) 2, . . ., N.
  • the DU 174 assigns the ID(s) 2, . . ., N.
  • the DU 174 includes the ID(s) 2, . . ., N in the first DU-to-CU message of the procedure 390.
  • the DU 174 includes the ID(s) 2, . . ., N in the DU-to-CU message(s) 2, . . . , N of the LTM preparation procedure(s) 2, . . . ,N.
  • the CU 172 can include the ID(s) 2, . . ., N in the RRC reconfiguration message.
  • the DU 174 includes the ID(s) 2, . .
  • the CU 172 does not include an ID (e.g., LTM ID) identifying each of the LTM DU configuration(s) 2, . . ., N in the RRC reconfiguration message, first container and/or element 1.
  • ID e.g., LTM ID
  • the CU 172 can generate a second container including the LTM DU configuration(s) 2, . . . , N or element(s) 2, . . . , N instead of using the first container.
  • the CU 172 then transmits an additional RRC reconfiguration message including the second container to the UE 102 via the DU 174, similar to the events 316 and 318.
  • the UE 102 transmits an additional RRC reconfiguration complete message to the CU 172 via the DU 174, similar to the events 320 and 322.
  • the second container can be a second addition or modification list (e.g., Itm- ConfigToAddModList field, LTM-ConfigToAddModList IE, Itm- CandidateConfigToAddModList field, or LTM-CandidateConfigToAddModList ⁇ E), and each of the element(s) 2, . . ., N can be an addition or modification IE (e.g., Itm-ConfigToAddMod field, LTM-ConfigToAddMod IE, Itm-CandidateConfigToAddMod field, or LTM- CandidateConfigToAddMod IE).
  • the UE 102 can store the second addition or modification list together with the first addition or modification list, e.g., in a variable in its random access memory (RAM).
  • RAM random access memory
  • the DU 174 includes cell ID(s) 2, . . . , N in the LTM DU configuration(s) 2, . . ., N to identify the cell(s) 2, . . ., N, respectively.
  • each of the cell ID(s) 2, . . . , N is a PCI.
  • the LTM DU configuration(s) 2, . . . , N includes cell index(es) 2 , . . . , N indexing the cell ID(s) 2, . . . , N or the cell(s) 2, . . . , N, respectively.
  • the CU 172 can set the cell index(es) 2, . . N to different value(s) and include the cell index(es) 2, . . N in the first CU-to CU-to-DU message of the event 308.
  • the CU 172 can set the cell index(es) 2, . . N to different values and include the cell index(es) 2, . . .
  • the CU 172 sets the cell index(es) 1, . . N to different values.
  • the cell ID(s) 1, . . ., N in the LTM DU configuration(s) 1, . . ., N are different from the cell ID(s) 1, . . ., N in the CU-to-DU message(s) described above.
  • each of the LTM DU configuration(s) 1, . . ., N includes physical configuration parameters, MAC configuration parameters, RLC configuration parameters and/or LI measurement configuration(s).
  • each of the LTM DU configuration(s) 1, . . ., N can be a CellGroupConfig IE as defined in 3GPP specification 38.331.
  • each of the LTM DU configuration(s) 1, . . . , N include configuration parameters included in a CellGroupConfig IE as defined in 3 GPP specification 38.331.
  • the plurality of configuration parameters in each of the LTM DU configuration(s) include a particular special cell configuration (e.g., SpCellConfig E) and/or one or more SCell configurations (e.g., SCellConfig IE(s)).
  • the LTM DU configuration(s) 1, . . ., N are CellGroupConfig IE(s) defined in 3GPP specification 38.331.
  • the LTM DU configuration(s) 1, . . ., N include configuration parameters in the CellGroupConfig IE.
  • the CU 172 can include one or more additional LTM CU configurations in at least one of the element(s) 2, . . . , N, the first container or the second container.
  • Each of the additional LTM CU configurations are associated with a particular LTM DU configuration of the LTM DU configuration(s) 2, . . . , N. Examples and implementations of the additional LTM CU configurations are similar to the LTM CU configuration 1.
  • the CU 172 determines to release the LTM DU configuration M of the LTM DU configuration(s) 1, . . . , N (or the element M of the element(s) 1, . . . , M). 1 ⁇ M ⁇ N.
  • the CU 172 transmits a RRC reconfiguration message to the UE 102 via the DU 174 to indicate the UE 102 to release the LTM DU configuration M or element M.
  • the CU 172 generates a release list including the ID (i.e., LTM ID) M for releasing the LTM DU configuration M or element M and includes the release list in the RRC reconfiguration message.
  • the UE 102 releases the LTM DU configuration M or element M and transmits a RRC reconfiguration complete message to the CU 172 via the DU 174.
  • the CU 172 transmits a CU-to-DU message to the DU 174 to indicate the DU 174 to release the LTM DU configuration M.
  • the CU 172 can include the cell ID M or the ID (i.e., LTM ID) M in a release indication (e.g., a field or IE) in the CU-to-DU message.
  • the DU 174 releases the LTM DU configuration M and transmits a DU-to-CU message to the CU 172.
  • the CU-to-DU message and DU-to-CU message are a UE Context Modification Request message and a UE Context Modification Response message, respectively.
  • the DU 174 determines to release the LTM DU configuration K. In response to the determination, the DU 174 transmits a DU-to-CU message to the CU 172 to release the LTM DU configuration K. To indicate the LTM DU configuration K is released, the DU 174 can include the cell ID K or the ID (i.e., LTM ID) K in a release indication (e.g., a field or IE) in the DU-to-CU message. 1 ⁇ K ⁇ N.
  • a release indication e.g., a field or IE
  • the CU 172 After (e.g., in response to) receiving the DU-to-CU message, the CU 172 generates a release list including the ID (i.e., LTM ID) K to release the LTM DU configuration K or element K and transmits a RRC reconfiguration message including the release list to the UE 102 via the DU 174.
  • the UE 102 releases the LTM DU configuration K or element K and transmits a RRC reconfiguration complete message to the CU 172 via the DU 174.
  • the CU 172 can transmit a CU-to-DU message to the DU 174 in response to the DU-to-CU message.
  • the DU-to-CU message and CU-to-DU message are a UE Context Modification Required message and a UE Context Modification Confirm message, respectively.
  • the UE 102 After receiving the RRC reconfiguration in the event 318 or transmitting the RRC reconfiguration complete message in the event 320, the UE 102 transmits 324 at least one measurement report to the DU 174, similar to the event 304.
  • the DU 174 may transmit 326 a DU-to-CU message including the at least one measurement report to the CU 172, similar to the event 306.
  • the DU 174 does not transmit the at least one measurement report to the CU 172.
  • the at least one measurement report of the event 324 include LI measurement report(s) or L3 measurement repot(s), as described for the event 304.
  • the UE 102 transmits 324 the at least one measurement report on PUCCH(s) and/or PUSCH(s) to the DU 174, similar to the event 304. In other implementations, the UE 102 transmits 324 at least one MAC CE including the at least one measurement report to the DU 174, similar to the event 304. In some implementations, the UE 102 does not transmit the LI measurement report(s) in format of RRC message(s) to the DU 174.
  • the UE 102 transmits 324 the at least one measurement report to the DU 174 in accordance with at least one measurement configuration.
  • the at least one measurement configuration configures the UE 102 to perform measurements and report measurement results.
  • the CU 172 transmits the at least one measurement configuration to the UE 102 via the DU 174.
  • the CU 172 can transmit one or more RRC messages (e.g., RRCReconfiguration message(s)) including the at least one measurement configuration to the UE 102 via the DU 174 in the event 302 and/or 316 and/or after the event 306 or 316.
  • the one or more RRC messages may or may not include the RRC reconfiguration message of the event 316.
  • the UE 102 performs measurements on one or more reference signals.
  • the one or more reference signals can include one or more SSBs and/or one or more CSI-RSs.
  • the UE 102 obtains the at least one LI measurement result and/or at least one L3 measurement result from the measurements and includes the at least one LI measurement result and/or at least one L3 measurement result in the at least measurement report of the event 324.
  • the DU 174 transmits the one or more reference signals on the cell 124A, the cell 1 and/or the cell(s) 2, . . ., N.
  • the one or more reference signals can be CSI-RS(s) or SSB(s).
  • the at least one measurement configuration includes L3 measurement configuration(s) (e.g., MeasConfig IE(s)), as described for the event 304.
  • the at least one measurement configuration includes or is LI measurement configuration(s), as described above.
  • the LI measurement configuration(s) can be CSI-MeasConfig IE(s) defined in 3GPP specification 38.331 V18.0.0 and/or later versions.
  • the LI measurement configuration(s) can include RS resource configuration(s) and/or report configuration(s).
  • the UE 102 transmits 324 the LI measurement report(s) on UL resources (e.g., PUCCH resources or PUSCH resources) to the DU 174 in accordance with the report configuration(s).
  • the DU 174 receives the LI measurement report(s) on the UL resources in accordance with the report configuration(s).
  • the report configuration(s) are or are similar to CSI-ReportConfig IE(s).
  • each of the report configuration(s) is a new RRC IE.
  • (each of) the report configuration(s) configures periodically reporting and/or event-triggered reporting of the LI measurement result(s).
  • the LI measurement report(s) is/are CSI report(s). In other implementations, the LI measurement report(s) is/are MAC CE(s). In some implementations, each of the measurement report(s) includes one or more RS resource indicators and/or one or more quantized measurement values. The UE 102 performs measurements on the RS(s) or the RS resource(s) in accordance with the RS resource configuration(s) and/or the report configuration(s) and obtains the quantized measurement values from the measurements. In some implementations, the RS resource indicator(s) indicates the RS(s) or a RS resource(s) where the UE 102 perform measurements or obtains the quantized measurement values.
  • the RS resource indicator(s) includes one or more SSB resource indicators (SSBRI(s)) and/or one or more CSI-RS resource indicators (CRI(s)).
  • the quantized measurement values can include one or more Ll-RSRP values and/or one or more Ll-SINR values.
  • the at least one measurement configuration includes new-type measurement configuration(s) (e.g., LTM measurement configuration(s)).
  • the new-type measurement configuration can be newly defined in a 3GPP specification vl 8.0.0 and/or later versions.
  • the new-type measurement configuration(s) includes reference signal resource configuration(s) configuring resources where the DU 174 transmits reference signal(s).
  • the reference signal resource configuration(s) include CSI-RS(s) and/or SSB(s).
  • the reference signal resource configuration(s) is/are CSI-ResourceConfig IE(s).
  • the new-type measurement configuration(s) include measurement report configuration(s), as described above.
  • the UE 102 transmits the measurement report(s) on PUCCH(s) or MAC CE(s) to the DU 174 in accordance with the measurement report configuration(s).
  • the DU 174 receives the measurement report(s) on PUCCH(s) or MAC CE(s) in accordance with the measurement report configuration(s).
  • the measurement report(s) can be LI measurement report(s) or new-type measurement report(s) (e.g., LTM measurement report(s)).
  • the new-type measurement configuration includes configuration parameters newly defined in a 3GPP specification vl 8.0.0 and/or later versions.
  • the DU 174 After (e.g., in response to) receiving the at least one measurement report in the event 324, the DU 174 generates a first LTM command to activate the LTM DU configuration 1 (i.e., the first LTM command commands the UE 102 to apply the LTM DU configuration 1 or to perform a serving cell change to the cell 1). The DU 174 then transmits 330 the first LTM command to the UE 102. In some implementations, the DU 174 transmits the first LTM command on the cell 124A to the UE 102. In other implementations, the DU 174 transmits the first LTM command on the cell 124D to the UE 102.
  • the DU 174 can include the ID 1 in the first LTM command to indicate the LTM DU configuration 1 or element 1, and the UE 102 determines (e.g., identifies) the LTM DU configuration 1 or element 1 in accordance with the ID 1.
  • the DU 174 can include the cell index 1 indexing the cell ID 1 in the first LTM command.
  • the UE 102 determines (e.g., identifies) the LTM DU configuration 1 or element 1, based on the cell index 1.
  • the UE 102 retrieves the cell index 1 from the LTM DU configuration 1 or element 1, and establishes an association 1 between the cell index 1 and the LTM DU configuration 1 or element 1.
  • the UE 102 decodes the LTM DU configuration 1 or element 1 to obtain the cell index 1, before receiving the first LTM command.
  • the UE 102 identifies the LTM DU configuration 1 or element 1 in accordance with the cell index 1 and the association 1.
  • the UE 102 Before receiving the first LTM command, the UE 102 retrieves the cell index(es) 2, . . . , N from the LTM DU configuration(s) or element(s) 2, . . . , N and establishes association(s) 2, . . . , N between the cell index(es) 2, . . . , N and the LTM DU configuration(s) or element(s) 2, . . . , N, respectively. In other words, the UE 102 decodes the LTM DU configuration(s) or element(s) 2, . . ., N to obtain the cell index(es) 2, . . . , N, before receiving the first LTM command.
  • the DU 174 includes cell ID 1 in the first LTM command, where the cell ID 1 identifies the cell 1.
  • the cell ID 1 included in the first LTM command is the same as the cell ID 1 included in the first CU-to- DU message.
  • the DU 174 determines the cell ID 1 (e.g., PCI) included in the first LTM command from the cell ID 1 (e.g., CGI) received in the first CU-to- DU message.
  • the UE 102 determines (e.g., identifies) the LTM DU configuration 1 or element 1, based on the cell ID 1.
  • the UE 102 Before receiving the first LTM command, the UE 102 retrieves the cell ID 1 from the LTM DU configuration 1 or element 1, and establishes an association 1 between the cell ID 1 and the LTM DU configuration 1 or element 1. In other words, the UE 102 decodes the LTM DU configuration 1 or element 1 to obtain the cell ID 1, before receiving the first LTM command. Thus, the UE 102 identifies the LTM DU configuration 1 or element 1 in accordance with the cell ID 1 (received in the first LTM command) and the association 1. Before receiving the first LTM command, the UE 102 retrieves the cell ID(es) 2, . . . , N from the LTM DU configuration(s) or element(s) 2, . . .
  • the DU 174 has a mapping table to store mappings between the PCI(s) 1, . . . , N and the CGI(s) 1, . . . , N for the cell(s) 1, ..., N, respectively.
  • the DU 174 can include a bit map in the first LTM command to activate the LTM DU configuration 1, instead of the ID 1 or cell index 1.
  • the number of bits in the bit map is larger than or equal to “N”.
  • bit 1, . . . , N corresponds to the cell index(es) 1, . . ., N, the ID(s) 1, . . ., N, the LTM DU configuration(s) 1, . . ., N or the element(s) 1, . .
  • bit 0 . . . , N-l corresponds to the cell index(es) 1, . . . , N, the ID(s) 1, . . . , N, the LTM DU configuration(s) 1, . . . , N or the element (s) 1, . . .
  • the DU 174 sets a corresponding bit (e.g., bit 0) in the bit map to a first value to indicate the cell index 1, the ID 1 the LTM DU configuration 1 or the element 1.
  • the UE 102 can determine the cell index 1, the ID 1 LTM DU configuration 1 or element 1 in accordance with the bit 0 set to the first value in the bit map.
  • the DU 174 sets the remaining bits in the bit map to a second value to indicate that the rest of the LTM DU configuration(s) 1, . . . , N is/are not activated.
  • the first value is one and the second value is zero. In other implementations, the first value is zero and the second value is one.
  • the DU 174 can set the corresponding bit (e.g., bit L or bit Z-7) in the bit map to the first value and set the remaining bits to the second value, where 1 ⁇ L ⁇ N. In some implementations, the DU 174 sets at most one bit in the bit map to the first value. [0114] After determining or identifying the LTM DU configuration 1 or element 1, the UE 102 then applies the LTM DU configuration 1 and/or LTM CU configuration, after (e.g., in response to) receiving the first LTM command.
  • the UE 102 After determining or identifying the LTM DU configuration 1 or element 1, the UE 102 then applies the LTM DU configuration 1 and/or LTM CU configuration, after (e.g., in response to) receiving the first LTM command.
  • the at least one measurement report (e.g., LI measurement report(s) or new-type measurement report(s)) of the event 324 includes at least one measurement result for the first cell, TRP(s) of the first cell or reference signal(s) transmitted on the first cell.
  • the reference signal(s) can be CSI-RS(s) or SSB(s).
  • the DU 174 determines to activate the LTM DU configuration 1 or transmit the first LTM command, based on the at least one measurement result. In some implementations, the DU 174 determines to activate the LTM DU configuration 1 because, when or if the at least one measurement result is above a second predetermined threshold.
  • the at least one measurement result includes Ll-RSRP value(s), Ll-RSRQ value(s) and/or Ll-SINR value(s). In other implementations, the at least one measurement result includes RSRP value(s), RSRQ value(s) and/or SINR value(s) for the new-type measurement report(s).
  • the second predetermined threshold is different from the first predetermined threshold. In one implementation, the second predetermined threshold is larger than the first predetermined threshold. In this case, the at least one measurement result indicates that the first cell is suitable for communication with the UE 102. In another implementation, the second predetermined threshold is equal to the first predetermined threshold.
  • the at least one measurement result indicates that the first cell has been continuously above the second predetermined threshold or the first predetermined threshold. This indicates that the first cell is suitable for communication with the UE 102.
  • the DU 174 determines to activate the LTM DU configuration 1 in response to that signal strength or quality of the first cell is above the second predetermined threshold for the UE 102.
  • the at least one measurement report (e.g., L3 measurement report(s)) of the events 324 and 326 includes at least one measurement result for the first cell.
  • the CU 172 determines to activate the LTM DU configuration 1 or transmit the first LTM command, because the at least one measurement result indicates that signal strength or quality of the first cell is above a second predetermined threshold.
  • the second predetermined threshold is different from the first predetermined threshold.
  • the second predetermined threshold is larger than the first predetermined threshold.
  • the at least one measurement report of the event 326 indicates that signal strength or quality of the first cell is suitable for communication with the UE 102.
  • the second predetermined threshold is equal to the first predetermined threshold.
  • the at least one measurement report of the event 326 indicates that signal strength or quality of the first cell has been continuously above the second predetermined threshold or the first predetermined threshold. This also indicates that the first cell is suitable for communication with the UE 102.
  • the CU 172 determines to activate the LTM DU configuration 1 in response to that signal strength or quality of the first cell is above the second predetermined threshold.
  • the CU 172 transmits 328 a fourth CU-to-DU message to the DU 174 to activate the LTM DU configuration 1 or trigger a serving cell change to the cell 1 for the UE 102.
  • the CU 172 includes the ID 1 in the fourth CU-to-DU message.
  • the CU 172 includes the cell index 1 in the fourth CU-to- DU message.
  • the DU 174 transmits 330 the first LTM command to the UE 102 and optionally transmits a fourth DU-to-CU message to the CU 172.
  • the CU 172 includes the cell index 1 in the fourth CU-to-DU message.
  • the DU 174 can determine to activate the LTM DU configuration 1 in accordance with the cell index 1.
  • the CU 172 can include the cell ID 1 in the fourth CU-to-DU message.
  • the DU 174 determines to activate the LTM DU configuration 1 in accordance with the cell ID 1.
  • the CU 172 can include the ID 1 in the fourth CU-to-DU message.
  • the DU 174 can determine to activate the LTM DU configuration 1 in accordance with the ID 1.
  • the fourth CU-to-DU message and fourth DU-to-CU message are a UE Context Modification Request message and a UE Context Modification Response message, respectively.
  • the fourth CU-to-DU message and/or fourth DU-to- CU message are new interface messages, e.g., Fl application protocol (F1AP) messages defined in 3GPP specification 38.473 vl8.0.0 and/or later versions.
  • Fl application protocol F1AP
  • the DU 174 can transmit 329 to the CU 172 a DU-to- CU message indicating LTM (being) executed.
  • the DU 174 includes the cell ID 1 or the ID 1 (i.e., LTM ID) in the DU-to-CU message 329 to indicate that the DU 174 is to activate the LTM DU configuration 1 or trigger a fast serving cell change (i.e., an LTM serving cell change).
  • the DU can transmit the DU-to-CU message 329 to the CU 172 before or after transmitting the LTM command 330.
  • the first LTM command is a MAC CE included in a MAC PDU that the UE 102 receives from the DU 174 in the event 330.
  • the MAC CE can be a new MAC CE defined in 3GPP specification 38.321 vl8.0.0 and/or later versions.
  • the DU 174 includes a subheader identifying the new MAC CE in the MAC PDU and the UE 102 identifies the new MAC CE in the MAC PDU in accordance with the subheader.
  • the subheader can include a logical channel ID or extended logical channel ID defined in a 3GPP specification to identify the new MAC CE.
  • the logical channel ID or extended logical channel ID are newly defined in 3GPP specification 38.321 vl 8.0.0 and/or later versions.
  • the first LTM command is a DCI that the UE 102 receives on a PDCCH from the DU 174 in the event 330.
  • the DU 174 generates a CRC for the DCI, scrambles the CRC with a first C-RNTI of the UE 102, and transmits the DCI and scrambled CRC on the PDCCH in the event 330.
  • a format of the DCI can be an existing DCI format defined in a 3GPP specification (e.g., 38.212).
  • the format of the DCI can be a new DCI format defined in a 3GPP specification (e.g., 38.212 V18.0.0 or later versions).
  • the DU 174 does not perform security protection (e.g., integrity protection and/or encryption) on the first LTM command. This speeds up processing the first LTM command in the UE 102 because the UE 102 does not perform security check (e.g., decryption and/or integrity check) on the first LTM command.
  • security protection e.g., integrity protection and/or encryption
  • the UE 102 may transmit 331 an acknowledgement to the DU 174 on the cell 124A or cell 124D to indicate that the UE 102 receives the first LTM command.
  • the acknowledgement is a HARQ ACK.
  • the acknowledgement is a MAC CE.
  • the MAC CE is an existing MAC CE defined in 3GPP specification 38.321 vl7.2.0 and/or later versions.
  • the MAC CE is a new MAC CE defined in 3GPP specification 38.321 vl8.0.0 and/or later versions.
  • the acknowledgement is a PUCCH transmission.
  • the CU 172 transmits 316 the RRC reconfiguration message in response to the L3 measurement report 306 for the first cell.
  • the CU 172 can transmit a first RRC reconfiguration message including the L3 measurement configuration (e.g., MeasConfig IE) to the UE 102 before the event 306.
  • the DU 174 transmits 330 the first LTM command in response to the LI measurement report(s) 324 for the first cell.
  • the CU 172 can transmit a second RRC reconfiguration message including the LI or new-type measurement configuration(s) to the UE 102.
  • the first and second RRC reconfiguration messages can be the same message (i.e., the same instance).
  • the first and second RRC reconfiguration messages are different messages.
  • the second RRC reconfiguration message is the RRC reconfiguration message of the event 316.
  • the second RRC reconfiguration message is different from the RRC reconfiguration message of the event 316.
  • the UE 102 accesses 332 the first cell.
  • the UE 102 identifies the LTM DU configuration 1 in accordance with the ID 1, the cell ID 1 or the cell index 1 received in the first LTM command and applies the LTM DU configuration 1 to communicate with the DU 174 on the first cell.
  • the UE 102 disconnects from the cell 124A, after (e.g., in response to) receiving the first LTM command or after transmitting 331 the acknowledgement.
  • the UE 102 stops communicating on the cell 124A after (e.g., in response to) receiving 330 the first LTM command or transmitting 331 the acknowledgement.
  • the UE 102 accesses the first cell by performing a random access procedure on the first cell with the DU 174, in response to receiving the first LTM command. In other implementations, the UE 102 skips a random access procedure and transmits the first transmission (e.g., a PUSCH transmission or a PUCCH transmission) on the first cell to the DU 174, after (e.g., in response to) receiving the first LTM command.
  • the first transmission e.g., a PUSCH transmission or a PUCCH transmission
  • the DU 174 configures the access of the UE 102 to the first cell, including whether or not the UE 102 performs a random access procedure, in the LTM DU configuration 1.
  • the UE 102 determines whether to perform a random access procedure on the first cell in accordance with the LTM DU configuration 1. If the LTM DU configuration 1 configures the UE 102 to perform a random access procedure, the UE 102 performs a random access procedure on the first cell in the event 332, in order to connect to the first cell.
  • the LTM DU configuration 1 includes a reconfiguration with sync configuration (e.g., ReconfigurationWithSync IE) to configure that the UE 102 performs a random access procedure when the UE 102 receives an LTM command for the first cell.
  • the DU 174 configures the UE 102 to skip the random access procedure for an LTM serving cell change to the first cell.
  • the UE 102 after receiving the first LTM command, the UE 102 skips the random access procedure and transmits the first transmission (e.g., a PUSCH transmission or a PUCCH transmission) on the first cell to the DU 174 in the event 332.
  • the DU 174 excludes a reconfiguration with sync configuration in the LTM DU configuration 1 to configure the UE 102 skipping a random access procedure for an LTM serving cell change to the first cell.
  • the LTM DU configuration 1 includes the reconfiguration with sync configuration or the random access configuration.
  • the DU 174 configures whether the UE 102 performs a random access procedure on the first cell in an LTM command.
  • the UE 102 determines whether to perform the random access procedure on the first cell in the event 332 in accordance with the first LTM command.
  • the DU 174 includes, in the first LTM command, an indication (e.g., a field) indicating skipping a random access procedure.
  • the UE 102 In response to the indication or the first LTM command including the indication, the UE 102 skips a random access procedure and directly transmits the first transmission (e.g., a PUSCH transmission or a PUCCH transmission) on the first cell to access the first cell.
  • the DU 174 excludes the indication in the first LTM command to configure the UE 102 to perform a random access procedure.
  • the UE 102 performs a random access procedure on the first cell to access the first cell.
  • the DU 174 includes a timing advance value in the first LTM command to indicate skipping a random access procedure.
  • the UE 102 In response to receiving the timing advance value or the first LTM command including the timing advance value, the UE 102 skips a random access procedure and transmits the first transmission on the first cell to access the first cell, using the timing advance value.
  • the DU 174 excludes, in the first LTM command, a timing advance value to configure the UE 102 to perform a random access procedure.
  • the UE 102 performs a random access procedure on the first cell to access the first cell.
  • the random access procedure is a four-step random access procedure. In other implementations, the random access procedure is a two-step random access procedure. In some implementations, the random access procedure is a contention-free random access procedure. In other implementations, the random access procedure is a contention-based random access procedure. In cases where the random access procedure is a four-step random access procedure, the UE 102 transmits a Message 3 including a UE identity to the DU 174 via the first cell in the random access procedure. The DU 174 transmits a contention resolution message (e.g., a Message 4) to the UE 102 in response to the Message 3.
  • a contention resolution message e.g., a Message 4
  • the UE 102 transmits a Message A including the UE identity to the DU 174 via the first cell in the random access procedure.
  • the DU 174 transmits a contention resolution message (e.g., Message B) to the UE 102 in response to the Message A.
  • the UE 102 determines that the UE 102 successfully completes the random access procedure (i.e., the UE 102 successfully accesses the first cell).
  • the LTM DU configuration 1 includes a second C-RNTI and the UE identity is the second C-RNTI of the UE 102.
  • the contention resolution message is a PDCCH transmission addressed to the second C-RNTI.
  • the LTM DU configuration 1 does not include a C-RNTI
  • the UE identity is the first C-RNTI.
  • the contention resolution message is a PDCCH transmission addressed to the first C-RNTI.
  • the DU 174 includes the second C-RNTI in the reconfiguration with sync configuration. In other implementations, the DU 174 includes the second C-RNTI in the LTM cell switch information.
  • the random access procedure is a contention free random access procedure.
  • the UE 102 transmits the dedicated random access preamble to the DU 174 via the first cell.
  • the UE 102 determines that the UE 102 successfully completes the random access procedure (i.e., the UE 102 successfully accesses the first cell).
  • the DU 174 configures the UE 102 to perform a random access procedure on the first cell as described above, the DU 174 will detect that the UE 102 has accessed the first cell when the DU 174 receives Message 3, Message A, or the dedicated preamble in the random access procedure. If the DU 174 configures the UE 102 to skip a random access procedure, the DU 174 will detect that the UE 102 has accessed the first cell when the DU 174 receives the first transmission. [0128] In some implementations, the UE 102 transmits the first transmission (e.g., the PUSCH transmission) on the first cell using a UL grant. In some implementations, the first LTM command includes the UL grant.
  • the first transmission e.g., the PUSCH transmission
  • the first LTM command includes the UL grant.
  • the UE 102 when the UE 102 performs an LTM serving cell change to the first cell in response to the first LTM command, the UE 102 receives a first DCI including the UL grant on a PDCCH on the first cell. In some implementations, the UE 102 attempts to receive the first DCI or the UL grant by monitoring one or more PDCCHs on the first cell in accordance with the LTM DU configuration 1, when the UE 102 switches to the first cell in response to the first LTM command. While monitoring one or more PDCCHs on the first cell, the UE 102 receives the first DCI and a CRC of the first DCI on the PDCCH.
  • the UE 102 determines that the first DCI was sent for the UE 102, using the CRC and the second C-RNTI. In the case that the LTM DU configuration 1 does not include the second C-RNT, the UE 102 determines that the first DCI was sent for the UE 102, using the CRC and the first C-RNTI.
  • the CU 172 transmits at least one first TCI state configuration to the UE 102 via the DU 174.
  • each of the first TCI state configuration(s) configures a TCI state for the UE 102 to transmit and/or receive data and/or control signal on the first cell.
  • Each TCI state associates one or two DL RSs with a corresponding QCL type and the DL RS(s) can be associated with a particular cell of the cell(s) 1, . . ., N.
  • the CU 172 receives a DU-to-CU message including the first TCI state configuration(s) from the DU 174 and transmits a RRC message including the first TCI state configuration(s) to the UE 102 via the DU 174.
  • the DU 174 includes the first TCI state configuration(s) in a serving DU configuration (e.g., CellGroupConfig ⁇ E) and includes the serving DU configuration in the DU-to-CU message.
  • the DU 174 includes the LTM DU configuration 1 in a first interface protocol lE/field in the message 312, and includes the serving DU configuration in a second interface protocol lE/field in the DU-to-CU message.
  • the first interface protocol lE/field is defined as part of a format of the DU-to-CU message.
  • the CU 172 includes the serving DU configuration in the RRC message. In some implementations, the CU 172 refrains from including the serving DU configuration in a container for LTM (e.g., the first container). In other implementations, the CU 172 includes the first TCI state configuration(s) in an element for LTM, an addition or modification list for LTM, or a container, similar to the element 1, the first addition or modification list, or the first container respectively.
  • the RRC message is the RRC reconfiguration message 316, 318 or another RRC reconfiguration message (not shown in Fig. 3).
  • the DU-to-CU message is the message 312, the message 314, a UE Context Modification Response message, or a UE Context Modification Required message.
  • the DU 174 also includes the first TCI state configuration(s) in the LTM DU configuration 1. In other implementations, the DU 174 refrains from including the first TCI state configuration(s) in the LTM DU configuration 1.
  • the first interface protocol lE/field is a first F1AP lE/field and the second interface protocol lE/field is a second Fl AP lE/field.
  • one of the first F1AP lE/field and the second F1AP lE/field is a F1AP CellGroupConfig lE/field and the other is not the F1AP CellGroupConfig lE/field.
  • the DU 174 includes the first Fl AP lE/field in a DU to CU RRC Information IE in the message 312 and includes the second F1AP lE/field in the DU to CU RRC Information IE in the DU-to-CU message.
  • neither the first F1AP lE/field nor the second F1AP IE is a F1AP CellGroupConfig lE/field.
  • the second Fl AP lE/field is the DU to CU RRC Information IE and the first F1AP lE/field is a new IE specific for including an LTM DU configuration.
  • each of the first TCI state configuration(s) includes a TCI state ID identifying the corresponding TCI state configuration.
  • the first TCI state configuration(s) includes TCI state configuration(s) 1, ..., L, where L is a positive integer larger than zero.
  • the TCI state configuration(s) 1, . . . , L include TCI state ID(s) 1, . . . , L identifying the TCI state configuration(s) 1, . .
  • the DU 174 includes the TCI state ID 1 in the first LTM command to indicate to the UE 102 to apply the TCI state configuration 1 to communicate on the first cell.
  • the UE 102 accesses and/or communicates on the first cell using the TCI state configuration 1 in accordance with the TCI state ID 1.
  • the UE 102 monitors one or more PDCCHs and/or transmits the first transmission, using the TCI state configuration 1.
  • the DU 174 detects that the UE 102 accesses the first cell and communicates with the UE 102 on the first cell, based on the TCI state configuration 1.
  • the DU 174 receives the first transmission from the UE 102 on the first cell, based on the TCI state configuration 1.
  • the DU 174 includes the TCI state ID 2 in the first LTM command to indicate to the UE 102 to apply the TCI state configuration 2 to communicate on the first cell, in addition to the TCI state ID 1.
  • the UE 102 accesses and/or communicates on the first cell using the TCI state configurations 1 and 2 in accordance with the TCI state ID 1 and the TCI state ID 2.
  • the UE 102 monitors one or more PDCCHs on the first cell using the TCI state configuration 1 and transmits the first transmission on the first cell using the TCI state configuration 2.
  • the UE 102 monitors one or more PDCCHs on the first cell using the TCI state configuration 1 and the TCI state configuration 2 and transmits the first transmission on the first cell using one of the TCI state configuration 1 and the TCI state configuration 2.
  • the DU 174 detects that the UE 102 accesses the first cell and communicates with the UE 102 on the first cell, based on the TCI state configuration 1 and/or the TCI state configuration 2. For example, the DU 174 receives the first transmission from the UE 102 on the first cell, based on one of the TCI state configuration 1 and the TCI state configuration 2.
  • the DU 174 determines to not include a TCI state ID in the first LTM command. In such cases, the UE 102 communicates on the first cell with the first DU using the at least one first TCI state, after (e.g., in response to) receiving the first LTM command. In some implementations, the DU 174 detects that the UE 102 accesses the first cell and communicates with the UE 102 on the first cell, based on the first TCI state configuration(s).
  • the DU 174 before transmitting the first LTM command, transmits one or more activation commands to activate some or all of the first TCI state configuration(s).
  • each of the activation command(s) is a MAC CE.
  • each of the activation command(s) is a DCI.
  • the DU 174 includes the TCI state ID 1 and/or TCI state ID 2 in the activation command(s) to activate the TCI state configuration 1 and/or the TCI state configuration 2, respectively. Accordingly, the UE 102 determines or identifies that the TCI state configuration 1 and/or the TCI state configuration 2 is/are activated upon receiving the activation command(s).
  • the DU 174 includes all the TCI state ID(s) for the first TCI state configuration(s) in the activation command(s). Accordingly, the UE 102 determines or identifies that the first TCI state configuration(s) is/are activated upon receiving the activation command(s). In some implementations, the DU 174 refrains from including, in the first LTM command, a TCI state ID for a TCI state configuration that the DU 174 has not activated for the UE 102. In some implementations, the DU 174 includes the cell ID 1 or the cell index 1 in the activation command(s).
  • the UE 102 determines that the activation command(s) activates the one or more TCI state configurations in the first TCI state configuration(s), where each of the TCI state ID(s) identifies a particular TCI state configuration of the TCI state configuration(s).
  • the UE 102 communicates with the DU 174 on the cell 124A (e.g., events 302, 304, 318, 320, 324, 330), using one or more TCI state configurations.
  • each of the TCI state configuration(s) configures a TCI state for the UE 102 to transmit and/or receive data and/or control signal on the cell 124 A.
  • the UE 102 stops using the TCI configuration(s) upon receiving the first LTM command.
  • the UE 102 After successfully accessing the first cell, the UE 102 communicates 336 with the DU 174 on the first cell using the LTM DU configuration 1 and/or reference LTM DU configuration and communicates with the CU 172 via the DU 174. In such cases, the DU 174 communicates 336 with the UE 102 on the first cell using the LTM DU configuration 1. In some scenarios or implementations, the UE 102 communicates 336 PUSCH transmissions, PDSCH transmissions, PUCCH transmissions, PDCCH transmissions, and/or sounding reference signal (SRS) transmissions with the DU 174 on the first cell.
  • SRS sounding reference signal
  • the UE 102 uses some or all of the first TCI state configuration(s) to perform 336 the communication with the DU 174.
  • the DU 174 uses some or all of the first TCI state configuration(s) to perform 336 the communication with the UE 102.
  • the DU 174 includes one or more additional TCI state configurations in the LTM DU configuration 1. In such cases, the DU 174 can transmit one or more activation commands to the UE 102 via the first cell in the event 336 to activate the additional TCI state configuration(s). The UE 102 determines that the additional TCI state configuration(s) is/are activated upon receiving the activation command(s).
  • each of the activation command(s) is a MAC CE. In other implementations, each of the activation command(s) is a DCI.
  • the UE 102 After receiving the activation command(s), the UE 102 uses the additional TCI state configuration(s) to communicate with the DU 174 on the first cell. Similarly, after transmitting the activation command(s), the DU 174 uses the additional TCI state configuration(s) to communicate with the UE 102 on the first cell.
  • the UE 102 communicates 336 with and the DU 174 on the first cell in accordance with the LTM DU configuration 1 and at least a portion of the reference LTM DU configuration. In other words, the UE 102 communicates 336 with the DU 174 in accordance with configuration parameters in the LTM DU configuration 1 and the reference LTM DU configuration. Similarly, the DU 174 communicates 336 with the UE 102 on the first cell in accordance with the LTM DU configuration 1 and at least a portion of the reference LTM DU configuration. In other words, the DU 174 communicates 336 with the UE 102 in accordance with configuration parameters in the LTM DU configuration 1 and the reference LTM DU configuration.
  • the UE 102 In the case that the UE 102 receives neither the LTM CU configuration 1 nor a/the reference LTM CU configuration, the UE 102 communicates 336 with the CU 172 via the DU 174 using the serving CU configuration. Correspondingly, if the CU 172 neither transmits the LTM CU configuration 1 nor a/the reference CU configuration to the UE 102, the CU 172 communicates 336 with the UE 102 via the DU 174 using the serving CU configuration.
  • the UE 102 communicates 336 with the CU 172 via the DU 174 using the LTM CU configuration 1 and (at least a portion of) the reference LTM CU configuration not augmented by the LTM CU configuration 1.
  • the CU 172 communicates 336 with the UE 102 via the DU 174 using the LTM CU configuration 1 and (at least a portion of) the reference LTM CU configuration not augmented by the LTM CU configuration 1.
  • the UE 102 In the case that the UE 102 receives the LTM CU configuration 1 and does not receive the reference LTM CU configuration from the CU 172, the UE 102 communicates 336 with the CU 172 via the DU 174 using the LTM CU configuration 1. In this case, the CU 172 communicates 336 with the UE 102 via the DU 174 using the LTM CU configuration 1. If the LTM CU configuration 1 is a full configuration, the UE 102 and CU 172 communicates 336 with each other via the DU 174 using the LTM CU configuration 1 instead of the serving CU configuration.
  • the UE 102 determines that the LTM CU configuration 1 is a full configuration.
  • the CU 172 determines to configure or configures the LTM CU configuration 1 as a full configuration, the CU 172 does not transmit a/the reference LTM CU configuration to the UE 102.
  • the CU 172 includes a first indication (e.g., a field or IE) in the LTM CU configuration 1, the first container, the element 1 or the RRC reconfiguration message 316 to indicate that the LTM CU configuration l is a full configuration.
  • the UE 102 and CU 172 communicates 336 with each other via the DU 174 using the LTM CU configuration 1 and at least a portion of the serving CU configuration not augmented by the LTM CU configuration 1. In some implementations, if the UE 102 does not receive a/the reference LTM CU configuration from the base station 104, the UE 102 determines that the LTM CU configuration l is a delta configuration to augment the serving CU configuration.
  • the CU 172 determines to configure or configures the LTM CU configuration 1 as a delta configuration to augment the serving CU configuration, the CU 172 does not transmit a/the reference LTM CU configuration to the UE 102.
  • the CU 172 indicates that the LTM CU configuration 1 is a delta configuration to augment to the serving CU configuration, by excluding the first indication in the LTM CU configuration 1, the first container, the element 1 and/or the RRC reconfiguration message 316.
  • the CU 172 includes a second indication (e.g., a field or IE) in the LTM CU configuration 1, the first container, the element 1 or the RRC reconfiguration message 316 to indicate that the LTM CU configuration l is a delta configuration to augment the serving CU configuration.
  • the CU 172 indicates that the LTM CU configuration 1 is a full configuration, by excluding the second indication in the LTM CU configuration 1, the first container, the element 1 and/or the RRC reconfiguration message 316.
  • the UE 102 In the case that the UE 102 receives the reference LTM CU configuration and does not receive the LTM CU configuration 1 from the CU 172, the UE 102 communicates 336 with the CU 172 via the DU 174 using the reference LTM CU configuration. In this case, the CU 172 communicates 336 with the UE 102 via the DU 174 using the reference LTM CU configuration. If the reference LTM CU configuration is a full configuration, the UE 102 and CU 172 communicates 336 with each other via the DU 174 using the reference LTM CU configuration instead of the serving CU configuration.
  • the UE 102 and CU 172 determine that the reference LTM CU configuration 1 is a full configuration as specified in a 3GPP specification (e.g., 3GPP specification 38.331 vl8.0.0 or later version).
  • the CU 172 includes a first indication (e.g., a field or IE) in the reference LTM CU configuration, the first container or the RRC reconfiguration message 316 to indicate that the reference LTM CU configuration is a full configuration.
  • a first indication e.g., a field or IE
  • the UE 102 and CU 172 communicates 336 with each other via the DU 174 using the reference LTM CU configuration and at least a portion of the serving CU configuration not augmented by the reference LTM CU configuration.
  • the CU 172 indicates that the reference LTM CU configuration is a delta configuration to augment to the serving CU configuration, by excluding the first indication in the reference LTM CU configuration, the first container, the element 1 and/or the RRC reconfiguration message 316.
  • the CU 172 includes a second indication (e.g., a field or IE) in the reference LTM CU configuration, the first container, the element 1 or the RRC reconfiguration message 316 to indicate that the reference LTM CU configuration is a delta configuration to augment the serving CU configuration.
  • the CU 172 indicates that the reference LTM CU configuration is a full configuration, by excluding the second indication in the reference LTM CU configuration, the first container, the element 1 and/or the RRC reconfiguration message 316.
  • the UE 102 In the case that the UE 102 neither receives the reference LTM CU configuration and nor the LTM CU configuration 1 from the CU 172, the UE 102 communicates 336 with the CU 172 via the DU 174 using the serving LTM CU configuration. In this case, the CU 172 communicates 336 with the UE 102 via the DU 174 using the serving LTM CU configuration.
  • the UE 102 transmits a RRC message (e.g., RRC reconfiguration complete message) to the CU 172 via the DU 174 and the first cell to indicate that the UE 102 applies the LTM DU configuration 1 and/or the LTM CU configuration 1.
  • a RRC message e.g., RRC reconfiguration complete message
  • the UE 102 can include the RRC message in the Message 3 or Message A.
  • the UE 102 transmits the RRC message after completing the random access procedure.
  • the UE 102 includes the RRC message in a PUSCH transmission of the at least one PUSCH transmission.
  • the UE 102 can transmit the RRC message to the base station 104 via the cell 124 A.
  • the DU 174 receives the RRC message, the DU 174 transmits the RRC message to the CU 172.
  • the UE 102 refrains from transmitting the RRC message to the base station 104 in response to applying the LTM DU configuration 1 or receiving the first LTM command.
  • the UE 102 can include or transmit data in the Message 3, Message A or PUSCH transmission as described above.
  • the UE 102 can generate a MAC PDU and/or a RLC PDU including the data and transmits or includes the MAC PDU and/or RLC PDU in the PUSCH transmission.
  • the data can be a PDCP PDU, a SDAP PDU, a LTE Positioning Protocol (LPP) PDU, a RRC PDU and/or a NAS PDU.
  • LPP LTE Positioning Protocol
  • the RRC PDU includes a UL-DCCH-Message excluding a RRC reconfiguration complete message.
  • the NAS PDU includes a Mobility Management (MM) message or a Session Management (SM) message.
  • the MM message can be a 5G MM message or a 6G MM message
  • the SM message can be a 5G SM message or a 6G SM message.
  • the DU 174 can transmit 334 a DU-to-CU message (e.g., Access Success message) to the CU 172 (e.g., a CP of the CU 172).
  • the DU 174 can include the cell ID 1 of the first cell in the DU-to-CU message of the event 334.
  • the cell ID can be a PCI or a CGI.
  • the CU 172 determines that the UE 102 connects to the first cell upon receiving the DU-to-CU message of the event 334.
  • the DU 174 can transmit a DL Data Delivery Status message or frame to the CU 172 (e.g., a UP of the CU 172).
  • the CU 172 stops or suspends transmitting DL data for the UE 102 to the DU 174 until receiving the DU-to-CU message 334.
  • the CU 172 may do so because the DU 174 cannot buffer DL data for the UE 102 during the LTM execution in the events 330 and/or 332.
  • the CU 172 After receiving the DU-to-CU message 334, the CU 172 continues or resumes transmitting DL data for the UE 102 to the DU 174. In other implementations, when the CU 172 receives the DU-to-CU message 329, the CU 172 continues transmitting DL data for the UE 102 to the DU 174. The CU 172 may do so because the DU 174 can buffer DL data for the UE 102 during the LTM execution in the events 330 and/or 332. When or after the DU 174 detects that UE 102 accesses the cell 1, the DU 174 transmits the DL data to the UE 102 via the cell 1.
  • the DU 174 when determining that the UE 102 connects to the first cell, transmitting 330 the first LTM command, or receiving 331 the acknowledgement, the DU 174 can stop communicating with the UE 102 on the cell 124A and/or release resources of the cell 124 A configured for the UE 102.
  • the DU 174 can generate some or all of the LTM DU configuration 1 and/or LTM DU configuration(s) 2, ..., N as full configuration(s) to replace the serving DU configuration. If the LTM DU configuration l is a full configuration, the UE 102 and DU 174 communicate 336 with each other in accordance with the LTM DU configuration 1 instead of the serving DU configuration.
  • the DU 174 includes an indication indicating that the LTM DU configuration 1 is a full configuration in the LTM DU configuration 1. In each of the LTM DU configured on(s) 2, . . . , N, the DU 174 can include an indication to indicate that the corresponding DU configuration is a full configuration.
  • Each of the indication(s) in the LTM DU configured on(s) 1, . . ., N can be a field or IE (i.e., the same field or IE).
  • the CU 172 can include, in the RRC reconfiguration message of the events 316, 318, a single indication indicating that the LTM DU configuration(s) 1 and/or 2, . . ., N is/are full configuration(s).
  • the CU 172 can include, in the additional RRC reconfiguration message, a single indication indicating that the LTM DU configuration(s) 2, . . ., N is/are full configured on(s).
  • the CU 172 can include, in the first container, a single indication indicating that the LTM DU configuration(s) 1 and/or 2, . . ., N is/are full configuration(s). In yet other implementations, for each of the LTM DU configuration(s) 2, . . ., N, the CU 172 can include, in the first container, a particular indication indicating the corresponding LTM DU configuration is a full configuration. In the case of the second container, the CU 172 can include, in the second container, a single indication indicating that the LTM DU configuration(s) 2, . . ., N is/are full configuration(s).
  • the CU 172 can include, in the element 1, includes an indication indicating that the LTM DU configuration 1 is a full configuration.
  • the CU 172 can include an indication indicating that the corresponding LTM DU configuration is a full configuration.
  • the UE 102 can determine that the LTM DU configuration 1 and/or LTM DU configuration(s) 2, . . ., N is/are full configuration(s) based on the indication(s) above.
  • each of the indication(s) above is different from a fullConfig field defined in the current 3GPP specification.
  • each of the indication(s) above is a fullConfig field defined in the current 3GPP specification.
  • the UE 102 in the event 336 does not apply the reference LTM DU configuration if received from the base station 104, e.g., in the RRC reconfiguration message 318.
  • the DU 174 may not include a/the reference LTM DU configuration in the first DU-to-CU message 310.
  • the DU 174 can generate the LTM DU configuration 1 and/or LTM DU configuration(s) 2, . . ., N as delta configuration(s) that augment (a portion of) the reference LTM DU configuration.
  • the DU 174 generates the LTM DU configuration(s) 1, . . .N based on the reference LTM DU configuration. For example, if the LTM DU configuration 1 is a delta configuration, the UE 102 and DU 174 augment (the portion of) the reference LTM DU configuration with the LTM DU configuration 1.
  • the UE 102 and DU 174 communicate 336 with each other in accordance with the LTM DU configuration 1 and unaugment portion of the reference LTM DU configuration.
  • the LTM DU configuration(s) 1, and/or 2. . ., N, first container, second container or element(s) 1, . . . , N exclude indication(s) indicating that the LTM DU configuration(s) 1, and/or 2. . ., N is/are full configuration(s) to indicate that the LTM DU configuration(s) 1 and/or 2, . . ., N is/are delta configuration(s).
  • the UE 102 can determine that each of the LTM DU configuration(s) 1 and/or 2, . .
  • N is a delta configuration based on that the indication is excluded in the LTM DU configuration(s) 1 and/or 2, . . ,,N, first container, second container or element(s) 1 and/or 2, . . ., N.
  • the UE 102 determines that the LTM DU configuration 1, and/or the LTM DU configuration(s) 2, . . ., N are full configuration(s).
  • the DU 174 does not obtain a reference LTM DU configuration for the UE 102 (i.e., the DU 174 does not generate a reference LTM DU configuration for the UE 102 and/or receive a reference LTM DU configuration for the UE 102 from the CU 172), the DU 174 generates the LTM DU configuration 1, and/or the LTM DU configuration(s) 2, . . ., N as full configuration(s).
  • the UE 102 determines that the LTM DU configuration 1, and/or the LTM DU configured on(s) 2, . . . , N are delta configured on(s) to augment the serving DU configuration. In such cases, the UE 102 communicates 336 with the DU 174 in accordance with the LTM DU configuration 1 and at least a portion of the serving DU configuration not augmented by LTM DU configuration 1.
  • the DU 174 does not obtain a reference LTM DU configuration for the UE 102 (i.e., the DU 174 does not generate a reference LTM DU configuration for the UE 102 and/or receive a reference LTM DU configuration for the UE 102 from the CU 172), the DU 174 generates the LTM DU configuration 1, and/or the LTM DU configuration(s) 2, . . ., N as delta configured on(s) to augment the serving DU configuration. In such cases, the DU 174 communicates 336 with the UE 102 in accordance with the LTM DU configuration 1 and the at least a portion of the serving DU configuration.
  • the UE 102 uses a UE MAC entity (e.g., MAC 204B) to communicate with a DU MAC entity (e.g., MAC 204B) of the DU 174 (e.g., the events 302, 304, 318, 320, 324, 330 and/or 331).
  • the UE 102 resets the UE MAC entity, after or in response to receiving the first LTM command and before performing 332 the random access procedure or communicating 336 with the DU 174 via the first cell.
  • the DU 174 resets the DU MAC entity after (e.g., in response to) transmitting the first LTM command, receiving the acknowledgement 331 or determining that the UE 102 connects to the first cell.
  • the UE 102 when the UE 102 resets the UE MAC entity, the UE 102 performs at least one of the following actions for the UE MAC entity (i.e., UE MAC reset or full UE MAC reset):initialize Bj for configured logical channel(s) to zero; stop one or more timers; consider timeAlignmentTimer(s) as expired, if the UE 102 is configured to perform the random access procedure (e.g., the event 332) in the configuration (e.g., the configuration 1); set new data indicator(s) (NDI(s)) for UL HARQ process(es) to value 0; set NDI(s) for HARQ process ID(s) to value 0 for monitoring PDCCH in Sidelink resource allocation mode 1; flush Msg3 buffer; flush MSGA buffer; cancel, if any, triggered Scheduling Request procedure; cancel, if any, triggered Buffer Status Reporting procedure; cancel, if any, triggered Power
  • the DU 174 when the DU 174 resets the DU MAC entity, the DU 174 performs at least one of the following actions for the DU MAC entity (i.e., DU MAC reset or full DU MAC reset): stop one or more timers; consider limeAlignmenlTimer( , that the DU 174 starts and/or maintains for the UE 102, as expired, if the UE 102 is configured to perform the random access procedure (e.g., the event 332) in the configuration (e.g., the configuration 1); set NDI(s) for DL HARQ process(es) to value 0; flush soft buffers for UL HARQ process(es); for each of the UL HARQ process(es), consider the next received transmission for a TB as the very first transmission; and reset one or more counters (e.g., BFI COUNTERs and/or LBT COUNTERs)
  • the UE 102 can determine to partially or fully reset the UE MAC entity.
  • the UE 102 when the UE 102 resets the UE MAC entity as described above, the UE 102 fully resets the UE MAC entity (i.e., a full UE MAC reset). In the full UE MAC reset, the UE 102 performs some or all of the actions described above.
  • the UE 102 when the UE 102 resets the UE MAC entity as described above, the UE 102 partially resets the UE MAC entity (i.e., a partial UE MAC reset). In the partial UE MAC reset, the UE 102 performs a subset or portion of the some or all of the actions in the full UE MAC reset.
  • the partial UE MAC reset includes at least one of the following actions: consider timeAlignmentTimer(s) of the UE 102 as expired, if the UE 102 is configured to perform the random access procedure (e.g., the event 332) in the configuration (e.g., the configuration 1); flush Msg3 buffer; flush MSGA buffer; release, if any, Temporary C-RNTI; or reset one or more counters (e g., BFI COUNTERs and/or LBT COUNTERs).
  • the random access procedure e.g., the event 332
  • the configuration e.g., the configuration 1
  • flush Msg3 buffer e.g., the configuration 1
  • flush MSGA buffer e.g., the configuration 1
  • release if any, Temporary C-RNTI
  • reset one or more counters e g., BFI COUNTERs and/or LBT COUNTERs.
  • the partial UE MAC reset further includes at least one of the following actions: cancel, if any, triggered Scheduling Request procedure; cancel, if any, triggered Buffer Status Reporting procedure; cancel, if any, triggered Power Headroom Reporting procedure; cancel, if any, triggered consistent LBT failure; cancel, if any, triggered BFR; cancel, if any, triggered Sidelink Buffer Status Reporting procedure; cancel, if any, triggered Pre-emptive Buffer Status Reporting procedure; cancel, if any, triggered Timing Advance Reporting procedure; cancel, if any, triggered Recommended bit rate query procedure; cancel, if any, triggered configured uplink grant confirmation; cancel, if any, triggered configured sidelink grant confirmation; cancel, if any, triggered Desired Guard Symbol query; or cancel, if any, triggered Positioning Measurement Gap Activation/Deactivation Request procedure;
  • the partial UE MAC reset further includes at least one of the following actions: stop a first portion of the one or more timers and retain the rest of the one or more timers; set new data indicator(s) (NDI(s)) for UL HARQ process(es) to value 0; set NDI(s) for HARQ process ID(s) to value 0 for monitoring PDCCH in Sidelink resource allocation mode 1; flush soft buffers for DL HARQ process(es); or for each of the DL HARQ process(es), consider the next received transmission for a TB as the very first transmission;
  • the DU 174 can determine to partially or fully reset the DU MAC entity.
  • the DU 174 when the DU 174 resets the DU MAC entity as described above, the DU 174 fully resets the DU MAC entity (i.e., a full DU MAC reset). In the full DU MAC reset, the DU 174 performs some or all of the actions described above.
  • the DU 174 when the DU 174 resets the DU MAC entity as described above, the DU 174 partially resets the DU MAC entity (i.e., a partial DU MAC reset). In the partial DU MAC reset, the DU 174 performs a subset or portion of the some or all of the actions in the full DU MAC reset.
  • the partial DU MAC reset includes at least one of the following actions in the partial MAC reset: consider limeAlignmenlTimer( , that the DU 174 starts and/or maintains for the UE 102, as expired, if the UE 102 is configured to perform the random access procedure (e.g., the event 332) in the configuration (e.g., the configuration 1); or reset one or more counters (e g., BFI COUNTERs and/or LBT COUNTERs)
  • the partial DU MAC reset includes at least one of the following actions for the MAC entity (i.e., DU MAC reset): stop a first portion of the one or more timers and retain the rest of the one or more timers; set NDI(s) for DL HARQ process(es) to value 0; flush soft buffers for UL HARQ process(es); for each of the UL HARQ process(es), consider the next received transmission for a TB as the very first transmission; or reset one or more counters (e.g., BFI COUNTERs and/or LBT COUNTERs)
  • the MAC entity i.e., DU MAC reset
  • the UE 102 refrains from resetting the UE MAC entity in response to receiving the first LTM command.
  • the DU 174 refrains from resetting the DU MAC entity after (e.g., in response to) transmitting the first LTM command, receiving the acknowledgement 331 or determining that the UE 102 connects to the first cell.
  • the UE 102 communicates with the DU 174 on the first cell using the UE MAC entity (not reset).
  • the DU 174 communicates with the UE 102 using the DU MAC entity (not reset) on the first cell during or after the random access procedure 332 or after determining that the UE 102 connects to the first cell.
  • the UE 102 uses at least one UE RLC entity (e.g., RLC 206B) to communicate RLC PDUs with at least one DU RLC entity (e.g., RLC 206B) of the DU 174 (e.g., the events 302, 304, 318, 320, 324, 330 and/or 331).
  • the UE 102 reestablishes some or all of the at least one UE RLC entity, after or in response to receiving the first LTM command and before performing 332 the random access procedure or communicating 336 with the DU 174 via the first cell.
  • the DU 174 reestablishes some or all of the at least one DU RLC entity after (e.g., in response to) transmitting the first LTM command, receiving the acknowledgement 331 or determining that the UE 102 connects to the first cell.
  • the LTM DU configuration 1 may or may not include one or more RLC reestablishment indications (e.g., reestablishRLC field(s)) configuring the UE 102 to reestablish some or all of the at least one UE RLC entity.
  • RLC reestablishment indications e.g., reestablishRLC field(s)
  • the LTM DU configuration 1 includes the a RLC reestablishment indication configuring the UE 102 to reestablish a first UE RLC entity, of the at least one UE RLC entity, that the UE 102 uses to communicate RLC PDU(s) with the DU 174
  • the UE 102 reestablishes the first UE RLC entity in response to the RLC reestablishment indication and the first LTM command.
  • the UE 102 can reestablish the first UE RLC entity before performing 332 the random access procedure or communicating 336 with the DU 174 via the first cell.
  • the UE 102 can reestablish the first UE RLC entity while or after performing 332 the random access procedure. Otherwise if the LTM DU configuration 1 does not include the RLC reestablishment indication, the UE 102 refrains from reestablishing the first UE RLC entity in response to the first LTM command. In some implementations, when the UE 102 reestablishes the first UE RLC entity, the UE 102 performs at least one of the following actions for the first UE RLC entity: discard RLC SDU(s), RLC SDU segment(s), and RLC PDU(s), if any; stop and reset timer(s), if running; or reset state variables to initial values. In some implementations, the state variables and timer(s) are defined in 3GPP specification 38.322.
  • the UE 102 refrains from reestablishing the first UE RLC entity upon or when receiving the first LTM command. In other words, the UE 102 refrains from preforming the actions for reestablishing the first UE RLC entity of the UE 102 upon or when receiving the first LTM command.
  • the LTM DU configuration 1 or element 1 does not include the RLC reestablishment indication and includes an indication indicating that the configuration l is a full configuration, the UE 102 can reestablish the first UE RLC entity of the UE 102 upon or when receiving the first LTM command.
  • the UE 102 refrains from reestablishing the first UE RLC entity upon or when receiving the first LTM command.
  • the DU 174 reestablishes some or all of at least one DU RLC entity (e.g., NR RLC 206B) that the DU 174 uses to communicate with the at least one UE RLC entity of the UE 102 (e.g., the events 302, 304, 318, 320, 324, 330 and/or 331) in response to the RLC reestablishment indication.
  • the DU 174 reestablishes a first DU RLC entity of the at least one DU RLC entity after transmitting the first LTM command, receiving an acknowledgement for the first LTM command from the UE 102, or determining that the UE 102 connects to the first cell.
  • the acknowledgement is a HARQ ACK. In other implementations, the acknowledgement is a MAC CE. In yet other implementations, the acknowledgement is a PUCCH transmission.
  • the DU 174 when the base station 104 reestablishes the first DU RLC entity, the DU 174 performs at least one of the following actions for the first DU RLC entity: discard RLC SDU(s), RLC SDU segment(s), and RLC PDU(s), if any; stop and reset timer(s), if running; or reset state variables to initial values. In some implementations, the state variables and timer(s) are defined in 3GPP specification 38.322.
  • the UE 102 refrains from reestablishing some or all of the at least one UE RLC entity in response to receiving the first LTM command.
  • the DU 174 refrains from reestablishing some or more of the at least one DU RLC entity after (e.g., in response to) transmitting the first LTM command, receiving the acknowledgement 331 or determining that the UE 102 connects to the first cell.
  • the UE 102 communicates with the DU 174 on the first cell using the some or all of the at least one UE RLC entity (not reestablished).
  • the some or all of the at least one UE RLC entity includes the first UE RLC entity and/or a second UE RLC entity.
  • the DU 174 communicates with the UE 102 using the some or all of the at least one DU RLC entity (not reestablished) on the first cell during or after the random access procedure 332 or after determining that the UE 102 connects to the first cell.
  • the some or all of the at least one DU RLC entity includes the first DU RLC entity and/or a second DU RLC entity.
  • the UE 102 uses at least one UE PDCP entity (e.g., PDCP 210) to communicate UL PDCP PDUs and/or DL PDCP PDUs with at least one CU PDCP entity (e.g., PDCP 210) of the CU 172 in the event 302.
  • the UE 102 performs a PDCP recovery procedure for some or all of the at least one UE PDCP entity, after or in response to receiving the first LTM command.
  • the UE 102 performs a PDCP recovery procedure for a first UE PDCP entity of the at least one UE PDCP entity, after or in response to receiving the first LTM command.
  • the UE 102 may or may not reestablish the first UE PDCP entity.
  • the UE 102 can retransmit at least a portion of the UL PDCP PDUs to the CU 172 via the DU 174 and the first cell in the event 336.
  • the CU 172 performs a PDCP recovery procedure for some or all of the at least one CU PDCP entity after or in response to transmitting the first LTM command.
  • the CU 172 performs a PDCP recovery procedure for a first CU PDCP entity of the at least one CU PDCP entity, after or in response to transmitting the first LTM command.
  • the CU 172 performs the PDCP recovery procedure for the first CU PDCP entity in response to receiving the DU-to-CU message 329 or 334. In other implementations, the CU 172 performs the PDCP recovery procedure for the first CU PDCP entity in response to receiving the DL Data Delivery Status message. In the PDCP recovery procedure, the CU 172 may or may not reestablish the first CU PDCP entity. After or in response to performing the PDCP recovery procedure, the CU 172 can retransmit at least a portion of the DL PDCP PDUs to the UE 102 via the DU 174 and the first cell in the event 336.
  • the UE 102 refrains from reestablishing some or all of the at least one UE PDCP entity in response to receiving the first LTM command.
  • the some or all of the at least one UE PDCP entity includes the first UE PDCP entity and/or a second UE PDCP entity.
  • the CU 172 refrains from reestablishing some or more of the at least one CU PDCP entity, after (e.g., in response to) receiving the DU-to-CU message 329 or 340 or after (e.g., in response to) receiving the DL Data Delivery Status message.
  • the UE 102 communicates with the CU 172 via the DU 174 and the first cell using the some or all of the at least one UE PDCP entity (not reestablished).
  • the some or all of the at least one UE PDCP entity includes the first UE PDCP entity and/or a second UE PDCP entity.
  • the CU 172 communicates with the UE 102 using the some or all of the at least one CU PDCP entity (not reestablished) via the DU 174 and the first cell.
  • the some or all of the at least one CU PDCP entity includes the first CU PDCP entity and/or a second CU PDCP entity.
  • the CU 172 can transmit 338 a CU-to-DU message (e.g., a UE Context Modification Request message or a UE Context Release Command message) to the DU 174 to indicate the DU 174 to stop communicating with the UE 102 and/or to release or suspend resources, of the cell 124A, configured for the UE 102.
  • a CU-to-DU message e.g., a UE Context Modification Request message or a UE Context Release Command message
  • the DU 174 can stop communicating on the cell 124A with the UE 102 and/or release or suspend resources, of the cell 124A, configured for the UE 102, and transmit 340 a DU-to-CU message (e.g., a UE Context Modification Response message or a UE Context Release Complete message) to the CU-172.
  • a DU-to-CU message e.g., a UE Context Modification Response message or a UE Context Release Complete message
  • the events 338 (optional) and 340 (optional) are collectively referred to in Fig. 3 as a resource release or modification procedure 396.
  • events 344, 346, 348, 350, 351, 352, 354 and/or 356 may occur, similar to the events 324, 326, 328, 330, 331, 332, 334 and/or 336, respectively.
  • the UE 102 transmits 344 at least one measurement report to the DU 174.
  • the at least one measurement report includes at least one measurement result for a second cell (i.e., the cell 2).
  • the at least one measurement result indicates that the second cell is suitable for communication with UE 102 and/or the first cell is not suitable for communication with the UE 102.
  • the DU 174 determines to activate the LTM DU configuration 2 and generates a second LTM command to activate the LTM DU configuration 2 (i.e., the second LTM command commands the UE 102 to apply the LTM DU configuration 2).
  • the DU 174 then transmits 350 the second LTM command to the UE on the first cell to the UE 102.
  • the DU 174 can transmit 349 to the CU 172 a DU-to-CU message indicating LTM (being) executed.
  • the DU 174 includes the cell ID 2 or the ID 2 (i.e., LTM ID) in the DU-to-CU message 349 to indicate that the DU 174 is to activate the LTM DU configuration 2.
  • the DU can transmit the DU-to-CU message 349 to the CU 172 before or after transmitting the LTM command 350.
  • the events 344, 346, 348, 350, 351, 352, 354 are collectively referred to in Fig. 3 as an LTM execution procedure 398.
  • the events 304, 306, 390, 392, 394, 324, 326, 328, 329, 330, 331, 332, 334, 336, 396, 398, 356 are collectively referred to in Fig. 3 as an LTM DU configuration and/or activation procedure 380.
  • the base station 104 includes a CU 172, a source DU (S-DU) 174A and a target DU (T-DU) 174B.
  • the S-DU 174A operates the cell 124 A and optionally additional cell(s), while the T-DU 174B operates a first cell (e.g., cell 124C).
  • the scenario 400 is similar to the scenario 300. Thus, the description of the scenario 300 can generally apply to the scenario 400. The differences between the scenarios 300 and 400 are described below.
  • the UE 102 communicates 402 with the S-DU 174A on cell 124A using a serving DU configuration and communicates with the CU 172 via the S-DU 174 A.
  • the S-DU 174A is a serving DU similar to the DU 174 in Fig. 3 A.
  • the UE 102 transmits 404, 406 at least one measurement report (e.g., L3 measurement report(s)) to the CU 172 via the S-DU 174 A. Based on the at least one measurement report, the CU 172 determines to prepare cell(s) 1, . .
  • N (operated by the T-DU 174B) for LTM for the UE 102, where N is a positive integer larger than 0 or 1.
  • the cell(s) 1, . . N are identified by cell ID(s) 1, . . ., N, respectively.
  • the CU 172 performs 490 an LTM preparation procedure with the T-DU 174B to (request the T-DU 174B to) prepare cell(s) 1, . . . , N for LTM for the UE 102.
  • N can be a positive integer larger than zero or 1.
  • the CU 172 transmits a CU-to-DU message including the cell ID(s) 1, . .
  • the T-DU 174B transmits a DU-to-DU message including the LTM DU configuration(s) 1, . . ., N to the CU 172, similar to the event 310.
  • the LTM DU configuration(s) 1, . . . , N configures the cell(s) 1, . . ., N for LTM, respectively.
  • the LTM DU configuration(s) 1, . . ., N include configuration parameters for communication on the cell(s) 1, . . ., N, respectively.
  • the CU-to-DU message and DU-to-CU message in the procedure 490 are UE Context Setup Request message and UE Context Setup Response message, respectively.
  • the CU 172 then transmits the LTM DU configuration(s) 1, . . ., N in a RRC reconfiguration message in an LTM configuration delivery procedure 494, similar to the LTM configuration delivery procedure 394.
  • the T-DU 174B can include cell index(es) 1, . . ., N in the LTM DU configuration(s) 1, . . ., N, respectively.
  • the CU 172 can set the cell index(es) 1, . . ., N to different values and include the cell index(es) 1, . . . , N in the CU-to-DU message of the procedure 490.
  • the CU 172 can perform an additional LTM preparation procedure(s) with the T-DU 174B to prepare cell(s) N+l, . . ., N+M for LTM for the UE 102, similar to the procedure 490.
  • M is a positive integer larger than zero.
  • the CU 172 may determine to do so based on one or more measurement reports received from the UE 102 via the S-DU 174A, similar to the events 404, 406.
  • the CU 172 transmits a CU-to-DU message including cell ID(s) N+l, . .
  • the T-DU 174B transmits a DU-to-DU message including the LTM DU configuration(s) N+l, . . . , N+M to the CU 172.
  • N+M configures the cell(s) N+l, . . . , N+M for LTM, respectively.
  • the LTM DU configuration(s) N+l, . . . , N+M include configuration parameters for communication on the cell(s) N+l, . . ., N+M, respectively.
  • the CU 172 then transmits the LTM DU configuration(s) N+l, . . . , N+M in a RRC reconfiguration message in an additional LTM configuration delivery procedure, similar to the LTM configuration delivery procedure 394 or 494.
  • the LTM preparation procedure 490 is a UE Context Setup procedure and the additional LTM preparation procedure is a UE Context Modification procedure.
  • the CU 172 and S-DU 174 A can perform the procedure 380 with the UE 102, as described for Fig. 3.
  • the procedure 380 the CU 172 and S-DU 174A performs the procedure(s) 390 and/or 392 to prepare cell(s) of the S-DU 174A for LTM for the UE 102.
  • the value N in the procedure 380 or described for Fig. 3 can be the same as or different from the value N described for Fig. 4.
  • the CU 172 can receive the first DU-to-CU message including the reference LTM DU configuration from the S-DU 174A in the event 310.
  • the CU 172 and S-DU 174A does not perform the procedure 380 with the UE 102.
  • the CU 172 can perform 488 a reference LTM DU configuration query procedure with the S-DU 174 A to obtain a reference LTM DU configuration.
  • the CU 172 transmits 460 a CU-to-DU message to the S-DU 174 A to request or query a reference LTM DU configuration.
  • the CU 172 can include an indication in the CU-to-DU message to request or query a reference LTM DU configuration.
  • the S-DU 174A transmits 462 a DU-to-CU message including a reference LTM DU configuration to the CU 172.
  • the indication is a reference LTM DU configuration query indication.
  • the indication is an LTM indication, and the CU 172 can include a query indication (e.g., GNB-DU Configuration Query IE) in the CU-to-DU message.
  • the CU 172 After receiving the reference LTM DU configuration (i.e., either in the procedure 390 or in the procedure 488), the CU 172 includes the reference LTM DU configuration (received from the S-DU 174A) in the CU-to-DU message in the LTM preparation procedure 490.
  • the T-DU 174B generates the LTM DU configuration(s) 1, . . ., N based on the reference LTM DU configuration received from the CU 172. In such cases, the T-DU 174B does not include a reference LTM DU configuration in the DU-to-CU message in the procedure 490.
  • the T-DU 174B does not include a reference LTM DU configuration in the DU-to-CU message in the additional LTM preparation procedure.
  • the CU 172 may not include the reference LTM DU configuration in CU-to-DU message in the additional LTM preparation procedure with the T-DU 174B.
  • the T-DU 174B generates the LTM DU configuration(s) N+l, . . N+M based on the reference LTM DU configuration received from the CU 172.
  • the CU 172 does not provide a reference LTM DU configuration to the T-DU 174B in the LTM preparation procedure 490.
  • the T- DU 174B generates a reference LTM DU configuration and generates the LTM DU configuration(s) 1, . . ., N based on the reference LTM DU configuration.
  • the T- DU 174B includes the reference LTM DU configuration in the DU-to-CU message in the procedure 490.
  • the CU 172 transmits the reference LTM DU configuration in the RRC reconfiguration message in the procedure 490.
  • the T-DU 174B In the case of the additional LTM preparation procedure, the T-DU 174B generates the LTM DU configuration(s) N+l, . . ., N+M based on the reference LTM DU configuration. In this case, the T-DU 174B may not include the reference LTM DU configuration in the DU-to-CU message in the additional LTM preparation procedure. In some implementations, the reference LTM DU configuration generated by the T-DU 174B is different from the reference LTM DU configuration generated by the S-DU 174A. In other implementations, the reference LTM DU configuration generated by the T-DU 174B is the same as the reference LTM DU configuration generated by the S-DU 174 A.
  • the CU 172 includes the LTM DU configuration(s) 1, . . ., N of the procedure 380 in the CU-to-DU message of the procedure 490, and the T-DU 174B generates the LTM DU configuration(s) 1, . . . , N and/or N+l, . . . , N+M, considering or based on configuration(s) in the LTM DU configuration(s) of the procedure 380.
  • the LTM DU configuration X of the procedure 380 includes at least one reference signal (RS) resource configuration X, where 1 ⁇ X ⁇ N.
  • RS resource configuration(s) X configures one or more RSs or one or more RS resources associated with the cell X of the S-DU 174A.
  • the RS(s) includes SSB(s) and/or CSI-RS(s).
  • the RS resource(s) includes SSB resource(s) and/or CSI-RS resource(s).
  • each of the RS resource configuration(s) X includes a RS resource configuration ID.
  • the RS resource configuration(s) X is/are (similar to) CSI-ResourceConfig IE(s).
  • the LTM DU configuration X includes a CSI-MeasConfig IE and the CSI-MeasConfig IE includes the CSI- ResourceConfig IE(s).
  • the T-DU 174B generates at least one report configuration 1 for reporting, on the cell 1 of the T-DU 174B, measurement results of the RS(s) or RS resource(s) and includes the report configuration(s) 1 in the LTM DU configuration 1.
  • the report configuration(s) 1 is/are (similar to) CSI-ReportConfig IE(s).
  • the T-DU 174B generates at least one RS resource configuration 1, considering or based on the RS resource configuration(s) X and includes the RS resource configuration(s) 1 in the LTM DU configuration 1. In some implementations, the T-DU 174B includes the RS resource configuration(s) X in the RS resource configuration(s) 1. In other implementations, the T-DU 174B includes each of the RS resource configuration(s) X in the RS resource configuration(s) 1, except the RS resource configuration ID(s) in the RS resource configuration(s) X. The T-DU 174B assigns a RS resource configuration ID to a value for each of the RS resource configuration(s) 1 (including the RS resource configuration(s) X) and includes the RS resource configuration ID in the corresponding RS resource configuration.
  • the report configuration(s) 1 configures one or more UL resources (e.g., PUCCH resources or PUSCH resources) on the cell 1 for the UE 102 to transmit measurement results.
  • each of the report configuration(s) 1 includes one or more RS resource configuration IDs identifying one or more RS resource configurations included in the RS resource configuration(s) 1.
  • the UE 102 After the UE 102 performs an LTM serving cell change to the cell 1 from the cell 124 A, the UE 102 communicates with the S-DU 174B (i.e., the T-DU 17B becomes a S-DU for the UE 102) and transmits measurement results on the UL resource(s) via the cell 1 to the S-DU 174B, in accordance with the report configuration(s) 1.
  • the S-DU 174B receives the measurement results on the UL resource (s) via the cell 1 from the UE 102, in accordance with the report configuration(s) 1.
  • each of the measurement results includes one or more RS resource indicators and/or one or more quantized measurement values.
  • the UE 102 performs measurements on the RS(s) or the RS resource(s) in accordance with the RS resource configuration(s) 1 and/or the report configuration(s) 1 and obtains the quantized measurement values from the measurements.
  • the RS resource indicator(s) indicates the RS(s) or a RS resource(s) where the UE 102 perform measurements or obtains the quantized measurement values.
  • the RS resource indicator(s) includes one or more SSB resource indicators (SSBRI(s)) and/or one or more CSI-RS resource indicators (CRI(s)).
  • the quantized measurement values may include one or more Ll-RSRP values and/or one or more Ll-SINR values.
  • the T-DU 174B also includes additional RS resource configuration(s) in the LTM DU configuration 1.
  • Each of the additional RS resource configuration(s) configures one or more additional RSs or one or more additional RS resources associated with the cell 1.
  • the additional RS(s) includes SSB(s) and/or CSI-RS(s).
  • the additional RS resource(s) includes SSB resource(s) and/or CSI-RS resource(s).
  • each of the additional RS resource configuration(s) includes a RS resource configuration ID.
  • the additional RS resource configuration(s) is/are (similar to) CSI-ResourceConfig IE(s).
  • the T-DU 174B includes the CSI-ResourceConfig IE(s) in the CSI-MeasConfig IE.
  • the T-DU 174B generates at least one additional report configuration for reporting, on the cell 1 of the T-DU 174B, measurement results of the RS(s) or RS resource(s) and includes the additional report configuration(s) in the LTM DU configuration 1.
  • the additional report configuration(s) is/are (similar to) CSI-ReportConfig IE(s).
  • the additional report configuration(s) configures one or more UL resources (e.g., PUCCH resources or PUSCH resources) on the cell 1 for the UE 102 to transmit measurement results.
  • each of the additional report configuration(s) includes one or more RS resource configuration IDs identifying one or more RS resource configurations included in the additional RS resource configuration(s).
  • the S-DU 174B receives the measurement results on the UL resource (s) via the cell 1 from the UE 102, in accordance with the additional report configuration(s).
  • each of the measurement results includes one or more RS resource indicators and/or one or more quantized measurement values.
  • the UE 102 performs measurements on the additional RS(s) or the additional RS resource(s) in accordance with the additional RS resource configuration(s) and/or the additional report configuration(s) and obtains the quantized measurement values from the measurements.
  • the RS resource indicator(s) indicates the additional RS(s) or a RS resource(s) where the UE 102 perform measurements or obtains the quantized measurement values.
  • the RS resource indicator(s) includes one or more SSB resource indicators (SSBRI(s)) and/or one or more CSI-RS resource indicators (CRI(s)).
  • the quantized measurement values may include one or more Ll-RSRP values and/or one or more Ll-SINR values.
  • the T-DU 174B can generate RS resource configuration(s) 2, . . N, and/or N+l, . . . , N+M and/or report configuration(s) 2, . . . , N, and/or N+l, . . . , N+M, considering or based on the RS resource configuration(s) X, and include the RS resource configuration(s) 2, . . . , N, and/or N+l, . . . , N+M and/or the report configuration(s) 2, . . . , N, and/or N+l, . . . , N+M in the LTM DU configuration(s) 2, . . . , N, and/or N+l, . . . , N+M, respectively, as described above.
  • the LTM DU configuration X of the procedure 380 includes at least one TCI state configuration X, where 1 ⁇ X ⁇ N.
  • Each of the TCI state configuration(s) X configures a TCI state that associates one or two DL RSs with a corresponding QCL type.
  • the DL RS(s) can be associated with the cell X operated by the S-DU 174A.
  • each of the TCI state configuration(s) X includes a TCI state ID.
  • each of the TCI state configuration(s) X is a TCI-State IE.
  • the TCI state configuration(s) X includes/is/are an ul-TCI-ToAddModList-r 17 field, one or more TCI-UL-State-r 17 IES, a dl-OrJointTCI-StateToAddModList-rl7 field, one or more TCI-State IEs, TCI- ActivatedConfig IE and/or a tci-StatesToAddModList field.
  • the LTM DU configuration X includes a PDSCH-Config IE and the PDSCH-Config IE includes the TCI state configuration(s) X.
  • the T-DU 174B generates at least one TCI state configuration 1, considering or based on the TCI state configuration(s) X and includes the TCI state configuration(s) 1 in the LTM DU configuration 1.
  • the TCI state configuration(s) 1 includes the TCI state configuration(s) X.
  • the T-DU 174B includes each of the TCI state configuration(s) X in the TCI state configuration(s) 1, except the TCI state ID(s) in the TCI state configuration(s) X.
  • the T-DU 174B assigns a TCI state ID to a value for each of the TCI state configuration(s) 1 (including the TCI state configuration(s) X) and includes the TCI state ID in the corresponding TCI state configuration. While the UE 102 and the S-DU 174B communicate 436 with one another, the S-DU 174B can transmit an LTM command to the UE 102 to command the UE 102 to perform a fast serving cell change to the cell X.
  • the S- DU 174B includes a TCI state ID in the LTM command to indicate to the UE 102 to apply a TCI state configuration identified by the TCI state ID to communicate on the cell X, where the TCI state configuration is one of the TCI state configuration(s) X or includes configurations of one of the TCI state configuration(s) X.
  • the T-DU 174B can generate TCI state configuration(s) 2, . . N, considering or based on the RS resource configuration(s) X, and include the TCI state configuration(s) 2, . . . , N, and/or N+l, . . . , N+M in the LTM DU configured on(s) 2, . . . , N, and/or N+l, N+M, respectively, as described above.
  • the CU 172 in cases where the CU 172 performs the procedure 380 after performing the procedure 490, the CU 172 includes the LTM DU configured on(s) 1, . . ., N of the procedure 490 in the CU-to-DU message of the procedure 380, and the S-DU 174 A generates the LTM DU configured on(s) 1, . . ., N of the procedure 380, considering or based on configurations in the LTM DU configuration(s) of the procedure 490, in a similar way as described above.
  • the CU 172 assigns ID(s) 1, . . ., N identifying the LTM DU configured on(s) 1, . . ., N (received from the T-DU 174B), respectively, and performs the procedure 492 with the T-DU 174B to provide the ID(s) 1, . . . , N and/or cell ID(s) 1, . . . , N to the T-DU 174B, similar to the procedure 392.
  • the T-DU 174B associates the ID(s) 1, . . . , N with the LTM DU configured on(s) 1, . . . , N and/or the cell ID(s) 1, . .
  • the T-DU 174B assigns ID(s) 1, . . ., N identifying the LTM DU configuration(s) 1, . . ., N (generated by the T-DU 174B), respectively and includes the ID(s) 1, . . . , N in the DU-to-CU message of the procedure 490, similar to the event 310.
  • the CU 172 assigns ID(s) N+l, . . ., N+M identifying the LTM DU configuration(s) N+l, . .
  • the T-DU 174B associates the ID(s) N+l, . . ., N+M with the LTM DU configuration(s) N+l, . . ., N+M and/or the cell ID(s) N+l, . . ., N+M, respectively.
  • the T-DU 174B assigns ID(s) N+l, .
  • N+M identifying the LTM DU configured on(s) N+l, . . . , N+M, respectively and includes the ID(s) 1, . . ., N in the DU-to-CU message of the additional LTM preparation procedure, similar to the event 310.
  • the CU 172 transmits 412 a CU-to-DU message including the ID(s) 1, . . ., N to the S-DU 174A and receives 414 a DU-to-CU message from the S-DU 174A in response.
  • the CU-to-DU message 412 and DU-to-CU message 414 are collectively referred to in Fig. 4 as an LTM ID transfer procedure 493 or an LTM cell index transfer procedure 493.
  • the message 412 and message 414 can be UE Context Modification Request message and UE Context Modification Response message, respectively.
  • the CU 172 includes the LTM DU configuration(s) 1, . .
  • the CU 172 includes the ID(s) 1, . . ., N in the CU-to-DU message 412.
  • the CU 172 includes the cell index(es) 1, . . ., N in the CU-to-DU message 412.
  • the CU 172 can perform multiple LTM ID transfer procedures to transmit the ID(s) 1, . . . , N, cell ID(s) 1, . . . , N and/or LTM DU configuration(s) 1, . . ., N to the S-DU 174 A.
  • the CU 172 includes particular portion of the ID(s) 1, . . . , N, cell ID(s) 1, . . . , N and/or LTM DU configuration(s) 1, . . . , N in a CU- to-DU message similar to the message 412.
  • the S-DU 174A associates the ID(s) 1, . . ., N with the LTM DU configured on(s) 1, . . ., N and/or the cell ID(s) 1, . . ., N, respectively.
  • the CU 172 can perform multiple LTM cell index transfer procedures to transmit the cell index(es) 1, . . .
  • the CU 172 includes particular portion of the cell index(es) 1, . . . , N, cell ID(s) 1, . . . , N and/or LTM DU configuration(s) 1, . . ., N in a CU-to-DU message similar to the message 412.
  • the S-DU 174A associates the cell index(es) 1, . . ., N with the LTM DU configured on(s) 1, . . ., N and/or the cell ID(s) 1, . . ., N, respectively.
  • the S-DU 174 A generates a first serving DU configuration, based on the LTM DU configuration(s) 1, 2,... , and/or N, and includes the first serving DU configuration in the DU-to-CU message 414.
  • the first serving DU configuration including configurations updating (e.g., augmenting, modifying or replacing) the serving DU configuration 402.
  • the first serving DU configuration includes configurations that are not included in the serving DU configuration 402.
  • the CU 172 transmits a RRC reconfiguration message including the first serving DU configuration to the UE 102.
  • the UE 102 applies the first serving DU configuration to communicate with the serving DU upon receiving the RRC reconfiguration message.
  • the RRC reconfiguration message is or is similar to the RRC reconfiguration message in the procedure 494.
  • the UE 102 communicates with the S-DU 174 A using configurations included in the serving DU configuration 402 and not updated by the first serving DU configuration.
  • the following are example implementations of generating the first serving DU configuration based on the LTM DU configuration 1, . . . , N.
  • the LTM DU configuration Y of the procedure 490 includes at least one RS resource configuration Y, where 1 ⁇ Y ⁇ N.
  • Each of the RS resource configuration(s) Y configures one or more RSs or one or more RS resources associated with the cell Y of the T-DU 174B.
  • the RS(s) includes SSB(s) and/or CSI-RS(s).
  • the RS resource(s) includes SSB resource(s) and/or CSLRS resource(s).
  • each of the RS resource configuration(s) Y includes a RS resource configuration ID.
  • the RS resource configuration(s) Y is/are (similar to) CSI-ResourceConfig IE(s).
  • the LTM DU configuration Y includes a CSI-MeasConfig IE and the CSI-MeasConfig IE includes the CSI-ResourceConfig IE(s).
  • the S-DU 174A generates at least one serving report configuration for reporting, on the cell 124 A, measurement results of the RS(s) or RS resource(s) and includes the serving report configuration(s) in the first serving DU configuration.
  • the serving report configuration(s) is/are (similar to) CSI-ReportConfig IE(s).
  • the S-DU 174 A generates at least one serving RS resource configuration, considering or based on the RS resource configuration(s) Y and includes the serving RS resource configuration(s) in the first serving DU configuration. In some implementations, the S-DU 174 A includes the RS resource configuration(s) Y in the serving RS resource configuration(s). In other implementations, the S-DU 174A includes each of the RS resource configuration(s) Y in the serving RS resource configuration(s), except the RS resource configuration ID(s) in the RS resource configuration(s) Y. The S-DU 174 A assigns a RS resource configuration ID to a value for each of the serving RS resource configuration(s) (including the RS resource configuration(s) Y) and includes the RS resource configuration ID in the corresponding serving RS resource configuration.
  • the serving report configuration(s) configures one or more UL resources (e.g., PUCCH resources or PUSCH resources) on the cell 124A for the UE 102 to transmit measurement results.
  • each of the serving report configuration(s) includes one or more RS resource configuration IDs identifying one or more RS resource configurations included in the serving RS resource configuration(s). While the UE 102 communicates with the S-DU 174 A, the UE 102 transmits measurement results on the UL resource(s) via the cell 124 A to the S-DU 174 A, in accordance with the serving report configuration(s) (e.g., event 424).
  • the S-DU 174A receives the measurement results on the UL resource (s) via the cell 124 A from the UE 102, in accordance with the serving report configuration(s).
  • each of the measurement results includes one or more RS resource indicators and/or one or more quantized measurement values.
  • the UE 102 performs measurements on the RS(s) or the RS resource(s) in accordance with the serving RS resource configuration(s) and/or the serving report configuration(s) and obtains the quantized measurement values from the measurements.
  • the RS resource indicator(s) indicates the RS(s) or a RS resource(s) where the UE 102 perform measurements or obtains the quantized measurement values.
  • the RS resource indicator(s) includes one or more SSB resource indicators (SSBRI(s)) and/or one or more CSI-RS resource indicators (CRI(s)).
  • the quantized measurement values may include one or more Ll-RSRP values and/or one or more Ll-SINR values.
  • the LTM DU configuration Y of the procedure 490 includes at least one TCI state configuration Y, where 1 ⁇ Y ⁇ N.
  • Each of the TCI state configuration(s) Y configures a TCI state that associates one or two DL RSs with a corresponding QCL type.
  • the DL RS(s) can be associated with the cell Y operated by the T-DU 174B.
  • each of the TCI state configuration(s) Y includes a TCI state ID.
  • each of the TCI state configuration(s) Y is a TCI-State IE.
  • the TCI state configuration(s) Y includes/is/are an ul-TCI-ToAddModList-r 17 field, one or more TCI-UL-State-r 17 IES, a dl-OrJointTCI-StateToAddModList-rl7 field, one or more TCI-State IEs, TCI- ActivatedConfig IE and/or a tci-StatesToAddModList field.
  • the LTM DU configuration Y includes a PDSCH-Config IE and the PDSCH-Config IE includes the TCI state configured on(s) Y.
  • the S-DU 174A generates at least one serving TCI state configuration, considering or based on the TCI state configuration(s) Y and includes the serving TCI state configuration(s) in the first serving DU configuration.
  • the serving TCI state configuration(s) 1 includes the TCI state configured on(s) Y.
  • the S-DU 174 A includes each of the TCI state configuration(s) Y in the serving TCI state configuration(s), except the TCI state ID(s) in the TCI state configured on(s) Y.
  • the S-DU 174A assigns a TCI state ID to a value for each of the serving TCI state configuration(s) (including the TCI state configuration(s) Y) and includes the TCI state ID in the corresponding serving TCI state configuration. While the S- DU 174 A communicate 436 with the UE 102, the S-DU 174 A may transmit an LTM command to the UE 102 to command the UE 102 to perform a fast serving cell change to the cell Y.
  • the S-DU 174A includes a TCI state ID in the LTM command to indicate to the UE 102 to apply a TCI state configuration identified by the TCI state ID to communicate on the cell Y, where the TCI state configuration is one of the TCI state configuration(s) Y or includes configurations of one of the TCI state configuration(s) Y.
  • the CU 172 transmits a CU-to-DU message including the ID(s) N+l, . . N+M to the S-DU 174A and receives a DU-to-CU message from the S-DU 174 A in response, similar to the CU-to-DU message 412 and the DU-to-CU message 414, respectively.
  • the CU 172 includes the LTM DU configuration(s) N+l, . . ., N+M and/or cell ID(s) N+l, . . ., N+M in the CU-to-DU message.
  • the CU 172 can perform multiple LTM ID transfer procedures to transmit the ID(s) N+l, . . ., N+M, cell ID(s) N+l, . . ., N+M and/or LTM DU configuration(s) N+l, . . ., N+M to the S-DU 174A.
  • the CU 172 includes particular portion of the ID(s) N+l, . . . , N+M, cell ID(s) N+l, . . . , N+M and/or LTM DU configuration(s) 1, . . ., N in a CU-to-DU message similar to the message 412.
  • the S-DU 174 A associates the ID(s) N+l, . . . , N+M with the LTM DU configured on(s) N+l, . . . , N+M and/or the cell ID(s) N+l, . . ., N+M, respectively.
  • the S-DU 174A generates a second serving DU configuration, based on the LTM DU configured on(s) N+l, N+2, . . . , and/or N+M, and includes the second serving DU configuration in the DU-to-CU message.
  • the second serving DU configuration including configurations updating (e.g., augmenting, modifying or replacing) the first serving DU configuration and/or updating configurations included in the serving DU configuration 402 and not updated by the first serving DU configuration.
  • the second serving DU configuration includes configurations that are not included in the first serving DU configuration.
  • the CU 172 transmits a RRC reconfiguration message including the second serving DU configuration to the UE 102 via the S-DU 174 A.
  • the UE 102 applies the second serving DU configuration to communicate with the serving DU upon receiving the RRC reconfiguration message.
  • the RRC reconfiguration message is or is similar to the RRC reconfiguration message in the procedure 494.
  • the UE 102 communicates with the S-DU 174 A using configurations included in the serving DU configuration 402 and/or the first serving DU configuration and not updated by the second serving DU configuration.
  • the S-DU 174 A generates one or more new LI measurement configurations, based on LI measurement configuration(s) in the LTM DU configuration(s) N+l, N+2,. . . , and/or N+M, and includes the new LI measurement configuration(s) in the second serving DU configuration.
  • the S- DU 174 A generates one or more new TCI state configuration, based on TCI state configuration(s) in the LTM DU configuration(s) N+l, N+2, . . . , and/or N+M, and includes the new TCI state configuration(s) in the second serving DU configuration.
  • value(s) of the ID(s) 1, . . ., N of the procedure 380 are different from value(s) of the ID(s) 1, . . . ., N, and the ID(s) N+l ,...., N+M described for the scenario 400.
  • value(s) of the cell ID(s) 1, . . ., N of the procedure 380 are different from value(s) of the cell ID(s) 1, . . .
  • value(s) of the cell index(es) 1, . . ., N of the procedure 380 are different from value(s) of the cell index(es) 1, . . . ., N, and the cell index(es) N+l ,...., N+M described for the scenario 400.
  • the UE 102 can transmit 424 at least one measurement report to the S-DU 174A, similar to the event 324.
  • the at least one measurement report (e.g., LI measurement report(s)) includes an event ID, first measurement result(s) for the cell 1 of the T-DU 174B, and/or includes second measurement result(s) for the cell 124A.
  • the first measurement result(s) can be or include RSRP, RSRQ and/or SINR that the UE 102 obtains from reference signal(s) transmitted on the cell 1.
  • the second measurement result(s) can be or include RSRP, RSRQ and/or SINR that the UE 102 obtains from reference signal(s) transmitted on the cell 124 A.
  • the event ID, RSRP, RSRQ and/or SINR are LI -event ID, LI -RSRP, LI -RSRQ and/or LI -SINR, respectively.
  • the S-DU 174A can transmit 430 a first LTM command (i.e., LTM command 1) including the ID 1 to the UE 102 to order the UE 102 to perform a serving cell change to the cell 1 of the T-DU 174B.
  • the first LTM command includes the ID 1 (i.e., LTM ID). In other implementations, the first LTM command includes the cell index 1.
  • the UE 102 receives the first LTM command, the UE 102 performs a serving cell change to the cell 1 from a serving cell in accordance with the LTM DU configuration 1.
  • the UE 102 may perform 432 (or, in some cases, refrain from performing) a random access procedure with the T-DU 174B, similar to the event 332.
  • the UE 102 After (e.g., in response to) receiving the first LTM command or completing the random access procedure 432, the UE 102 communicates 436 with the T-DU 174B on the first cell using the LTM DU configuration 1 and/or reference LTM DU configuration and communicates with the CU 172 via the T-DU 174B, similar to the event 336. If a serving cell change occurs in the procedure 380, the serving cell can be the cell 1 or cell 2 of the S-DU 174A. Otherwise, if no serving cell change occurs in the procedure 380 or the procedure 380 is not performed, the serving cell is the cell 124 A.
  • the UE 102 identifies the LTM DU configuration 1 and/or cell ID 1 (i.e., the cell 1), based the LTM ID 1, as described for Fig. 3. If the first LTM command includes the cell index 1, the UE 102 identifies the LTM DU configuration 1, cell ID 1 (i.e., the cell 1) and/or LTM ID 1, based the cell index 1, as described for Fig. 3. The UE 102 applies the LTM DU configuration 1 to communicate with the T-DU 174B, after (e.g., in response to) receiving the first LTM command or successfully accessing the cell 1.
  • the S-DU 174 A can transmit 429 to the CU 172 a DU- to-CU message indicating LTM (being) executed.
  • the S-DU 174 A includes the cell ID 1 or the LTM ID 1 in the DU-to-CU message 429 to indicate that the S- DU 174A is to activate the LTM DU configuration 1 or trigger an LTM serving cell change.
  • the S-DU 174 A can transmit the DU-to-CU message 429 to the CU 172 before or after transmitting the LTM command 430.
  • the CU 172 stops or suspends transmitting DL data for the UE 102 to the S-DU 174A until receiving the DU-to-CU message 434. After receiving the DU-to-CU message 434, the CU 172 starts, continues or resumes transmitting DL data for the UE 102 to the T-DU 174B. When or after the T-DU 174B detects that UE 102 accesses the cell 1, the T-DU 174B transmits the DL data to the UE 102 via the cell 1.
  • the resource release procedure 496 can be similar to the procedure 396.
  • the CU 172 can transmit a CU-to-DU message (e.g., a UE Context Release Command message) to the S-DU 174 A to release a UE context of the UE 102.
  • a CU-to-DU message e.g., a UE Context Release Command message
  • the S-DU 174 A releases a UE context of the UE 102 and transmits 440 a DU-to-CU message (e.g., a UE Context Release Complete message) to the [0200]
  • a DU-to-CU message e.g., a UE Context Release Complete message
  • the events 380, 404, 406, 490, 492, 494, 494, 424, 426, 428, 429, 430, 431, 432, 434, 436, 496, 498, 456 are collectively referred to in Fig. 4 as an LTM configuration and/or activation procedure 480.
  • the base station 106 operates as an
  • the MN, and the base station 104 operates as an SN.
  • the SN 104 includes a CU 172 and a DU 174.
  • the scenario 500A is similar to the scenario 300, except that the scenario 500A is a DC scenario and the scenario 300 is a single connectivity (SC) scenario.
  • the MN 106 can include a CU and a DU similar to the base station 104 of Fig. 3.
  • the UE 102 in DC communicates with the MN 106 and with SN 104.
  • the UE 102 communicates with the DU 174 on cell 124A using a serving DU configuration and communicates with the CU 172 via the DU 174 using a serving CU configuration, similar to the event 302.
  • the UE 102 does not communicate with the CU 172 via the DU 174 in the event 302.
  • the UE 102 in DC can communicate 502 UL PDUs and/or DL PDUs with the MN 106 and/or SN 104 via radio bearers which can include SRBs and/or DRB(s).
  • the MN 106 and/or the SN 104 can configure the radio bearers to the UE 102.
  • the UE 102 in DC communicates 502 UL PDUs and/or DL PDUs with the SN 104 on an SCG (i.e., SCG radio resources) that the SN 104 configures for communication with the UE 102.
  • the UE 102 in DC communicates UL PDUs and/or DL PDUs with the MN 106 on an MCG (i.e., MCG radio resources) in accordance with a MN configuration (i.e., MCG configuration).
  • the serving DU configuration is a SN configuration (i.e., SCG configuration).
  • the MN 106 configures the MCG which includes at least one serving cell (e.g., the cell 126 and/or other cell(s)) operated by the MN 106.
  • the SN 106 A configures the SCG which includes at least one serving cell (e.g., the cell 124A and/or other cell(s)) operated by the SN 104.
  • the MN configuration includes multiple configuration parameters and the UE 102 receives the configuration parameters in one or more RRC messages from the MN 106.
  • the serving DU configuration includes multiple configuration parameters.
  • the UE 102 receives these configuration parameters in one or more RRC messages from the SN 104, e.g., via the MN 106 and/or on an SRB (e.g., SRB3) that the MN 106 or SN 104 configures to exchange RRC messages between the UE 102 and the SN 104.
  • SRB e.g., SRB3
  • the MN 106 can perform 580 an LTM DU configuration and/or activation procedure with the UE 102, similar to the procedures 380 and/or 480.
  • the UE 102 while communicating in DC with the MN 106 and SN 104, can transmit the at least one measurement report to the CU 172 via the DU 174 and cell 124A in the events 504 and 506, similar to the events 304 and 306, respectively.
  • the UE 102 while communicating in DC with the MN 106 and SN 104, can transmit 505 at least one measurement report to the MN 106 via the cell 126.
  • the MN 106 in turn transmits 507 the at least one measurement report to the CU 172.
  • the MN 106 generates at least one SN message including the at least one measurement report and transmits the at least one SN message to the CU 172 in the event 507.
  • the at least one SN message include RRC Transfer message(s) and/or SN Modification Request message(s).
  • the SN 104 determines to prepare the first cell for the UE 102, as described for Fig. 3.
  • the events 590, 592, 594, 524, 526, 528, 529, 530, 531, 532, 534, 536, 596, 598, and 556 are similar to the events 390, 392, 394, 324, 326, 328, 329, 330, 331, 332, 334, 336, 396, 398, and 356, respectively.
  • the UE 102 operating in DC with the MN 106 and SN 104 communicates 536 with the DU 174 on the first cell in accordance with the LTM DU configuration 1 and communicates 536 with the CU 172 via the DU 174, similar to the event 336.
  • the DU 174 and/or CU 172 can perform the LTM execution procedure 598 with the UE 102 to command the UE 102 to perform a cell change from the first cell to the second cell, similar to the procedure 398 or 498.
  • the UE 102 operating in DC with the MN 106 and SN 104 communicates 556 with the DU 174 on the second cell in accordance with the LTM DU configuration 2 and communicates 556 with the CU 172 via the DU 174, similar to the event 356.
  • the events 504, 506, 505, 507, 590, 592, 594, 524, 526, 528, 529, 530, 531, 532, 534, 536, 596, 598, 556 are collectively referred to in Fig. 5A as an LTM DU configuration and/or activation procedure 581.
  • a scenario 500B is generally similar to the scenario 500A, except that the SN 104 transmits 517, 519 the RRC reconfiguration message to the UE 102 via the MN 106 and receives 521, 523 the RRC reconfiguration complete message from the UE 102 via the MN 106.
  • the RRC reconfiguration message 517, 519 is similar to the RRC reconfiguration message 316, 318.
  • the RRC reconfiguration complete message 521, 523 is similar to the RRC reconfiguration message 320, 322.
  • the SN 104 generates a first SN message (e.g., SN Modification Required message, SN Modification Required message, or RRC Transfer message) including the RRC reconfiguration message and transmits the first SN message to the MN 106 in the event 517.
  • the MN 106 generates a MN RRC message including the RRC reconfiguration message and transmits 519 the MN RRC message to the UE 102.
  • the UE 102 generates a MN RRC response message including the RRC reconfiguration complete message and transmits 521 the MN RRC response message to the MN 106.
  • the MN 106 generates a second SN message (e.g., SN Reconfiguration Complete message or RRC Transfer message) including the RRC reconfiguration complete message and transmits the second SN message to the SN 104 in the event 523.
  • a second SN message e.g., SN Reconfiguration Complete message or RRC Transfer message
  • the MN RRC message and MN RRC response message can be a RRC reconfiguration message and a RRC reconfiguration complete message, respectively.
  • the UE 102 transmits a first RRC message (e.g., RRC reconfiguration complete message) to the CU 172 via the MN 106.
  • the first RRC message is to indicate that the UE 102 applies an LTM DU configuration and/or an LTM CU configuration, as described for Fig. 3.
  • the RRC reconfiguration message 517, 519 includes an LTM configuration and the LTM configuration includes the LTM DU configuration and/or the LTM CU configuration.
  • the CU 172 wraps the LTM DU configuration and/or the LTM CU configuration in a RRC message (e.g., RRCReconfiguration message) and includes the RRC message in the LTM configuration.
  • the CU 172 includes a first transaction ID in the RRC message included in the LTM configuration.
  • the UE 102 sets a second transaction ID to a value of the first transaction ID and includes the second transaction ID in the first RRC message.
  • the UE 102 transmits a second RRC message including the first RRC message to the MN 106.
  • the MN 106 retrieves the first RRC message from the second RRC message and transmits the first RRC message to the CU 172.
  • the second RRC message is a UL information transfer message for MR-DC (e.g., ULInformationTransferMRDC message) and the first RRC message is a RRCReconfigurationComplete message.
  • the events 504, 506, 505, 507, 590, 592, 594, 517, 519, 521, 523, 524, 526, 528, 529, 530, 531, 532, 534, 536, 596, 598, 556 are collectively referred to in Fig. 5B as an LTM DU configuration and/or activation procedure 582.
  • the base station 106 operates as an MN
  • the base station 104 operates as an SN, similar to the scenarios 300-500B.
  • the SN 104 includes a CU 172, an S-DU 174A and a T-DU 174B, similar to the base station 104 in the scenario 400.
  • the MN 106 can perform 680 an LTM DU configuration and/or activation procedure with the UE 102, similar to the procedures 380 and/or 480.
  • the CU 172 can perform 681 an LTM DU configuration and/or activation procedure with the UE 102 via the M-DU 174A or S-DU 174B, similar to the procedure 581 or 582.
  • a scenario 600B similar to the scenarios 300-500B and 600 A, except that that the SN 104 transmits 617, 619 the RRC reconfiguration message to the UE 102 via the MN 106 and receives 621, 623 the RRC reconfiguration complete message from the UE 102 via the MN 106.
  • the base station 104 operates as an MN and an SN, similar to the scenarios 300-600B.
  • the base station 104 includes a CU 172, a master DU (M-DU) 174 A and a secondary DU (S-DU) 174B.
  • the CU 172 operates with the M-DU 174A as a MN, similar to the base station 104 in Fig. 3 or the MN 106 in Figs. 5A-6B, and the CU 172 operates with the S-DU 174B as a SN, similar to the SN 104 in Figs. 5A-6B.
  • the UE 102 initially communicates 702 in DC with the M-DU 174A and S-DU 174B and communicates 702 with the CU 172 via the M-DU 174A and S- DU 174B.
  • the UE 102 communicates with the S-DU 174B on cell 124 A using a serving DU configuration and communicates with the CU 172 via the S-DU 174B using a serving CU configuration, similar to the event 302.
  • Events 704 and 706 are similar to the events 304 and 306.
  • the UE 102 can transmit 705 at least one measurement report to the M-DU 174A, similar to the event 304.
  • the M-DU 174A in turn transmits 707 at least one DU-to-CU message including the at les tone measurement report to the CU 172, similar to the event 306. While the UE 102 communicates in DC with the M-DU 174A and S-DU 174B, the CU 172 can perform 780 an LTM DU configuration and/or activation procedure with the UE 102 via the M-DU 174A, similar to the procedure 380.
  • the events 704, 706, 705, 707, 790, 792, 794, 724, 726, 728, 729, 730, 731, 732, 734, 736, 796, 798, 756 are collectively referred to in Fig. 7A as an LTM configuration and/or activation procedure 781.
  • a scenario 700B similar to the scenarios 300-600B and 700A, except that that the CU 172 transmits 717, 719 the RRC reconfiguration message to the UE 102 via the M-DU 174 A and receives 721, 723 the RRC reconfiguration complete message from the UE 102 via the M-DU 174 A.
  • the events 704, 706, 705, 707, 790, 792, 794, 717, 719, 721, 723, 724, 726, 728, 729, 730, 731, 732, 734, 736, 796, 798, 756 are collectively referred to in Fig. 7B as an LTM DU configuration and/or activation procedure 782.
  • the base station 104 operates as an MN and an SN, similar to the scenarios 300-700B.
  • the base station 104 includes a CU 172, a master DU (M-DU) 174A, a secondary DU (S-DU) 174B and a target secondary DU (T- DU) 174C.
  • the CU 172 operates with the M-DU 174A as a MN and operates with the S-DU 174B as a SN.
  • the CU 172 can perform 880 an LTM DU configuration and/or activation procedure with the UE 102 via the M-DU 174A, similar to the procedure 380. While the UE 102 communicates in DC with the M-DU 174A and S-DU 174B, the CU 172 can perform 881 an LTM DU configuration and/or activation procedure with the UE 102 via the S-DU 174A, similar to the procedure 581 or 582.
  • a scenario 800B similar to the scenarios 300-700B and 800 A, except that that the CU 172 transmits 817, 819 the RRC reconfiguration message to the UE 102 via the M-DU 174 A and receives 821, 823 the RRC reconfiguration complete message from the UE 102 via the M-DU 174 A.
  • Fig. 9 illustrates an example method 900, which can be implemented by a RAN (e.g., the RAN 105, the base station(s) 104 and/or 106, or the MN 106 and/or the SN 104).
  • the method 900 begins at block 902, where the RAN receives a first LTM capability of the UE for the first CG.
  • the RAN receives a second LTM capability of the UE for LTM for the second CG.
  • the RAN configures the UE one or more LTM configurations for the first CG, based on the first LTM capability (e.g., events 308, 310, 390, 312, 314, 392, 316, 318, 394, 380, 488, 490, 492, 494, 493, 480, 580, 680, 780, 880).
  • the first LTM capability e.g., events 308, 310, 390, 312, 314, 392, 316, 318, 394, 380, 488, 490, 492, 494, 493, 480, 580, 680, 780, 880.
  • the RAN configures the UE one or more LTM configurations for the second CG, based on the second LTM capability (e.g., events 590, 592, 594, 517, 519, 688, 690, 692, 694, 693, 617, 619, 790, 792, 794, 717, 719, 888, 890, 892, 894, 893, 817, 819).
  • the first CG is a MCG and the second CG is a SCG.
  • the RAN receives the first LTM capability and the second LTM capability from the UE.
  • a base station e.g., base station 104 or 106 of the RAN transmits a UE capability enquiry message to the UE.
  • the UE transmits a UE capability information to the baes station.
  • the UE includes the first LTM capability and the second LTM capability in the UE capability information message.
  • the UE includes the first LTM capability and the second LTM capability for a dual connectivity (DC) band combination in the UE capability information.
  • DC dual connectivity
  • the UE supports multiple DC band combinations and includes the first LTM capability and the second LTM capability for each of the DC band combinations in the UE capability information message.
  • the first LTM capability and the second LTM capability are irrelevant to a DC band combinations.
  • the base station transmits the first LTM capability and the second LTM capability to a CN (e.g., a MME or an AMF) and the CN stores the first and second LTM capabilities for the UE.
  • the CN transmits the first and second LTM capabilities to the RAN.
  • the RAN does not request the UE to transmit the first and second LTM capabilities to the RAN.
  • the RAN receives the first and second UE capabilities for the UE from the CN because the CN received the first and second UE capabilities for the UE from another base station in a similar way as described above.
  • the base station receives the first and second UE capabilities for the UE from another base station during a handover preparation procedure or a SN addition procedure.
  • the UE includes the first LTM capability and the second LTM capability in a UE capability IE and includes the UE capability IE in the UE capability information message.
  • the UE capability IE is a UE-NR-Capability IE.
  • the UE capability is a UE-MRDC-Capability IE.
  • the UE includes the first LTM capability and the second LTM capability for each of the DC band combinations in the UE capability IE.
  • the UE includes the first LTM capability (e.g., for one or multiple frequency bands or regardless of bands or band combinations) in an addition UE capability IE (e.g., for single connectivity scenarios) and includes the additional UE capability IE in the UE capability information message.
  • the additional UE capability IE is a UE-NR-Capability IE and the UE capability is a UE-MRDC-Capability IE.
  • the base station transmits the UE capability IE and/or the additional UE capability IE to the CN and the CN stores the UE capability IE and/or the additional UE capability IE for the UE.
  • the CN transmits the UE capability IE and/or the additional UE capability IE to the RAN.
  • the RAN does not request the UE to transmit the UE capability IE and/or the additional UE capability IE to the RAN.
  • the RAN receives the UE capability IE and/or the additional UE capability IE for the UE from the CN because the CN received the UE capability IE and/or the additional UE capability IE for the UE from another base station in a similar way as described above.
  • the base station receives the UE capability IE and/or the additional UE capability IE for the UE from another base station during a handover preparation procedure or a SN addition procedure.
  • the UE includes the first LTM capability and the second LTM capability in a first UE capability IE and a second UE capability, respectively.
  • the UE includes the first UE capability IE and the second UE capability IE in the UE capability information message.
  • the first UE capability IE is a UE-NR-Capability IE
  • the second UE capability IE is a UE-MRDC-Capability IE.
  • the UE includes the first LTM capability for one or multiple frequency bands in the first UE capability IE, and includes the second LTM capability for one or multiple frequency bands in the second UE capability IE.
  • the base station transmits the first UE capability IE and/or the second UE capability IE to the CN and the CN stores the first UE capability IE and/or the second UE capability IE for the UE.
  • the CN transmits the first UE capability IE and/or the second UE capability IE to the RAN.
  • the RAN does not request the UE to transmit the first UE capability IE and the second UE capability IE to the RAN.
  • the RAN receives the first UE capability IE and/or the second UE capability IE for the UE from the CN because the CN received the first UE capability IE and/or the second UE capability IE for the UE from another base station in a similar way as described above.
  • the base station receives the first UE capability IE and/or the second UE capability IE for the UE for the UE from another base station during a handover preparation procedure.
  • the first LTM capability indicates a maximum number of LTM configurations that the UE supports (e.g., stores) for the first CG.
  • the second LTM capability indicates a maximum number of LTM configurations that the UE supports (e.g., stores) for the second CG.
  • the RAN receives a third LTM capability of the UE for the first CG, indicating support of early uplink synchronization for the first CG. Based on the third LTM capability, the RAN can prepare a first early uplink synchronization configuration for the UE and transmits the first early uplink synchronization configuration to the UE (e.g., events 308, 310, 390, 312, 314, 392, 316, 318, 394, 380, 488, 490, 492, 494, 493, 480, 580, 680, 780, 880).
  • the first early uplink synchronization configuration configures early uplink synchronization for a candidate cell for the first CG.
  • the RAN determines that the UE does not support early uplink synchronization for the first CG and refrains from transmitting an early uplink synchronization configuration for the first CG to the UE in response to the determination.
  • the RAN receives a fourth LTM capability of the UE for the second CG, indicating support of early uplink synchronization for the second CG. Based on the fourth LTM capability, the RAN can prepare a second early uplink synchronization configuration for the UE and transmits the second early uplink synchronization configuration to the UE (e.g., events 590, 592, 594, 517, 519, 688, 690, 692, 694, 693, 617, 619, 790, 792, 794, 717, 719, 888, 890, 892, 894, 893, 817, 819).
  • events 590, 592, 594, 517, 519, 688, 690, 692, 694, 693, 617, 619, 790, 792, 794, 717, 719, 888, 890, 892, 894, 893, 817, 819 e.g., events 590, 592, 594, 517, 519
  • the second early uplink synchronization configuration configures early uplink synchronization for a candidate cell for the second CG. If the RAN does not receive the fourth LTM capability for a UE, the RAN determines that the UE does not support early uplink synchronization for the second CG and refrains from transmitting an early uplink synchronization configuration for the second CG to the UE in response to the determination.
  • Examples and implementations described for the first LTM capability and the second LTM capability may apply to the third LTM capability and/or the fourth LTM capability.
  • the third LTM capability and the fourth LTM capability are defined as capabilities per frequency band or per DC band combination.
  • the third LTM capability and the fourth LTM capability are defined as capabilities regardless of a frequency band and/or a DC band combination.
  • the RAN does not receive the first LTM capability of the UE, the RAN does not configure LTM for the first CG to the UE. In other implementations, if the RAN does not receive the second LTM capability of the UE, the RAN does not configure LTM for the second CG to the UE.
  • Fig. 10A illustrates an example method 1000 A, which can be implemented by a RAN (e.g., the RAN 105, the base station(s) 104 and/or 106, or the MN 106 and/or the SN 104).
  • a RAN e.g., the RAN 105, the base station(s) 104 and/or 106, or the MN 106 and/or the SN 104.
  • the method 1000 A begins at block 1002, where the RAN communicates with a UE via a first RAN node and a second RAN node (e.g., events 502, 602, 702, 802).
  • the RAN receives a first LTM capability of the UE for a first CG.
  • the RAN receives a second LTM capability of the UE for LTM for a second CG.
  • the RAN transmits coordination information to the first RAN node and/or the second RAN node.
  • the RAN configures the UE at least on LTM configurations for the first CG, based on the first LTM capability and the coordination information (e.g., events 308, 310, 390, 312, 314, 392, 316, 318, 394, 380, 488, 490, 492, 494, 493, 480, 580, 680, 780, 880).
  • the coordination information e.g., events 308, 310, 390, 312, 314, 392, 316, 318, 394, 380, 488, 490, 492, 494, 493, 480, 580, 680, 780, 880.
  • the RAN configures the UE one or more LTM configurations for the second CG, based on the first LTM capability and the coordination information (e.g., events 590, 592, 594, 517, 519, 688, 690, 692, 694, 693, 617, 619, 790, 792, 794, 717, 719, 888, 890, 892, 894, 893, 817, 819).
  • the coordination information e.g., events 590, 592, 594, 517, 519, 688, 690, 692, 694, 693, 617, 619, 790, 792, 794, 717, 719, 888, 890, 892, 894, 893, 817, 819.
  • the first LTM capability indicates that the UE supports LTM for the first CG and the second LTM capability indicates that the UE supports LTM for the second CG.
  • the coordination information indicates (e.g., configures or includes) a first maximum number of LTM configurations for the first CG that the first RAN node can configure for the UE.
  • the number of the LTM configuration(s) for the first CG is not larger than the first maximum number.
  • the second RAN node derives a second maximum number of LTM configurations for the second CG that the second RAN node can configure for the UE, based on the first maximum number, the second LTM capability and/or a total maximum number of LTM configurations for the second CG.
  • the total maximum number is predefined in a 3GPP specification.
  • the total maximum number is preconfigured in the second RAN node.
  • the second RAN node receives the total maximum number from the first RAN node, a CU of the RAN or an Operation, Administration and Maintenance (OAM) node.
  • OAM Operation, Administration and Maintenance
  • the coordination information indicates (e.g., configures or includes) a second maximum number of LTM configuration(s) for the second CG that the second RAN node can configure for the UE.
  • the number of the LTM configuration(s) for the second CG is not larger than the second maximum number.
  • the first RAN node and the second RAN node are a first DU and a second DU respectively.
  • the CU transmits the coordination information to the first DU and/or the second DU.
  • the CU transmits a CU-to-DU message including the coordination information to the first DU.
  • the CU transmits a CU-to-DU message including the coordination information to the second DU.
  • the first RAN node and the second RAN node are a MN and a SN respectively.
  • the MN transmits a SN message including the coordination information to the SN.
  • the SN transmits a SN message including the coordination information to the MN.
  • Fig. 1 OB is a flow diagram of an example method 1000B similar to the method 1000A, except that method 1000B includes blocks 1105, 1109 and 1111 instead of blocks 1104, 1106, 1108 and 1110.
  • the RAN receives an LTM capability of the UE for a first CG and a second CG.
  • the RAN configures the UE one or more LTM configurations for the first CG, based on the LTM capability and the coordination information.
  • the RAN configures the UE one or more LTM configurations for the second CG, based on the LTM capability and the coordination information.
  • the LTM capability in Fig. 10B indicates that the UE supports LTM for the first CG and the second CG.
  • the LTM capability indicates a total maximum number of LTM configurations that the UE supports (e.g., stores) for the first CG and the second CG.
  • the RAN configures the LTM configuration(s) for the first CG and the LTM configuration(s) for the second CG, the RAN ensures that a sum of the number of the LTM configuration(s) for the first CG and the number of the LTM configuration(s) for the second CG is not larger than the total maximum number.
  • the RAN receives an additional LTM capability of the UE, indicating support of early uplink synchronization for the first CG and the second CG. Based on the additional LTM capability, the RAN can prepare a first early uplink synchronization configuration for the UE and transmits the first early uplink synchronization configuration to the UE (e.g., events 308, 310, 390, 312, 314, 392, 316, 318, 394, 380, 488, 490, 492, 494, 493, 480, 580, 680, 780, 880).
  • the first early uplink synchronization configuration configures early uplink synchronization for a candidate cell for the first CG.
  • the RAN can prepare a second early uplink synchronization configuration for the UE and transmits the second early uplink synchronization configuration to the UE (e.g., events 590, 592, 594, 517, 519, 688, 690, 692, 694, 693, 617, 619, 790, 792, 794, 717, 719, 888, 890, 892, 894, 893, 817, 819).
  • the second early uplink synchronization configuration configures early uplink synchronization for a candidate cell for the second CG.
  • the RAN determines that the UE does not support early uplink synchronization for the first CG and the second CG and refrains from transmitting an early uplink synchronization configuration to the UE in response to the determination.
  • Examples and implementations described for Fig. 9 can apply to Figs. 10A and 10B. Examples and implementations described for Fig. 10A can apply to Fig. 10B. Examples and implementations described for the first LTM capability or the second LTM capability in Fig. 10A can apply to the LTM capability and the additional LTM capability.
  • Fig. 11 A illustrates an example method 1100 A, which can be implemented by a MN (e.g., the MN 106 in Figs. 5A-6B and the MN 104 in Figs. 7A-8B).
  • a MN e.g., the MN 106 in Figs. 5A-6B and the MN 104 in Figs. 7A-8B.
  • the method 1100 A begins at block 1102, where the MN communicates with a UE on a serving cell, where the UE operates in DC with the MN and a SN (e.g., 502, 602, 702, 802).
  • the MN determines to configure LTM for the UE.
  • the MN transmits an LTM configuration configuring a first cell to the UE (e.g., events 308, 310, 390, 312, 314, 392, 316, 318, 394, 380, 488, 490, 492, 494, 493, 480, 580, 680, 780, 880).
  • the MN transmits an LTM command to the UE, commanding a serving cell change to the first cell (e.g., events 330, 380, 430, 480, 580, 680, 780, 880).
  • the MN detects that the UE accesses the first cell (e.g., events 332, 380, 432, 480, 580, 680, 780, 880).
  • the MN communicates with the UE via the first cell (e.g., events 336, 380, 436, 480, 580, 680, 780, 880).
  • the MN transmits a SN Release Request message to the SN to initiate release of resources configured for the UE, after (e.g., in response) to transmitting the LTM command or detecting the UE accesses the first cell.
  • the MN initiates release of resources configured for the UE at block 1114 because the UE does not support LTM serving cell change while in dual connectivity.
  • the SN stops transmitting data to the UE and/or receiving data from the UE and transmits a SN Release Request Acknowledge message to the MN, in response to the SN Release Request message.
  • the MN transmits a Context Release message to the SN to release a context of the UE after receiving the SN Release Request Acknowledge message.
  • Fig. 1 IB is a flow diagram of an example method 1100B similar to the method 1100A, except that method 1100B includes block 1107 instead of block 1114.
  • the MN transmits a SN Release Request message to the SN to initiate release of resources configured for the UE, in response to (determining) configuring LTM for the UE or transmitting the LTM configuration to the UE.
  • the MN initiates release of resources configured for the UE at block 1107 because the UE does not support LTM serving cell change while in dual connectivity.
  • FIG. 12A illustrates an example method 1200 A, which can be implemented by a CU (e.g., the CU 172 in Figs. 8A-8B).
  • a CU e.g., the CU 172 in Figs. 8A-8B.
  • the method 1200 A begins at block 1202, where the CU communicates with a UE via a first DU and a second DU (e.g., events 702, 802).
  • the CU determines to configure LTM for the UE.
  • the CU receives, from a third DU, an LTM DU configuration configuring a first cell (e.g., event 490).
  • the CU transmits the LTM DU configuration to the UE (e.g., events 494).
  • the CU receives a DU- to-CU message from the third DU, indicating the UE accesses the first cell (e.g., events 432).
  • the CU communicates with the UE via the third DU and the first cell (e.g., event 436).
  • the CU transmits a UE Context Release Command message to the second DU to initiate release of resources configured for the UE, after (e.g., in response to) receiving the DU-to-CU message (e.g., event 496).
  • the CU initiates release of resources configured for the UE at block 1214 because the UE does not support LTM serving cell change while in dual connectivity.
  • the second DU stops transmitting data to the UE and/or receiving data from the UE and transmits a UE Context Release Complete message to the MN, in response to the UE Context Release Command message.
  • Fig. 12B is a flow diagram of an example method 1200B similar to the method 1200A, except that method 1200B includes block 1209 instead of block 1214.
  • the CU transmits a UE Context Release Command message to the second DU to initiate release of resources configured for the UE, in response to (determining) configuring LTM for the UE, receiving the LTM DU configuration, or transmitting the LTM DU configuration.
  • Fig. 13 illustrates an example method 1300, which can be implemented by a RAN (e.g., the RAN 105, the base station(s) 104 and/or 106, or the CU 172 of the base station 104 or 106).
  • a RAN e.g., the RAN 105, the base station(s) 104 and/or 106, or the CU 172 of the base station 104 or 106.
  • the method 1300 begins at block 1302, where the RAN communicates with a UE (e.g., events 302, 402, 502, 602, 702, 802).
  • the RAN determines whether the UE operates in dual connectivity (DC). If the RAN determines that the UE operates in DC at block 1304, the flow proceeds to block 1306. At block 1306, the RAN refrains from configuring LTM for the UE. Otherwise, if the RAN determines that the UE does not operate in DC at block 1304, the flow proceeds to block 1308.
  • the RAN configures LTM for the UE.
  • Fig. 14 illustrates an example method 1300, which can be implemented by a RAN (e.g., the RAN 105, the base station(s) 104 and/or 106, or the CU 172 of the base station 104 or 106).
  • a RAN e.g., the RAN 105, the base station(s) 104 and/or 106, or the CU 172 of the base station 104 or 106.
  • the method 1400 begins at block 1402, where the RAN communicates with a UE operating in DC with the first RAN node and a second RAN node (e.g., events 302, 402, 502, 602, 702, 802).
  • the RAN determines whether the UE is configured with LTM by the second RAN node. If the RAN determines that the UE is configured with LTM by the second RAN node at block 1404, the flow proceeds to block 1406.
  • the RAN refrains from configuring LTM for the UE. Otherwise, if the RAN determines that the UE is not configured with LTM by the second RAN node at block 1404, the flow proceeds to block 1408.
  • the RAN configures LTM for the UE.
  • Figs. 9A-1 IB Examples and implementations described for Figs. 9A-1 IB can apply to Figs. 13 and 14.
  • one of the first RAN node and the second RAN node is a MN and the other is a SN.
  • Fig. 15 illustrates an example method 1500, which can be implemented by a RAN (e.g., the RAN 105, or the MN(s) 104, 106 and/or the SN 104).
  • a RAN e.g., the RAN 105, or the MN(s) 104, 106 and/or the SN 104.
  • the method 1500 begins at block 1502, where the RAN communicates with a UE operating in DC with a MN and a SN (e.g., 502, 602, 702, 802).
  • the RAN configures LTM for the UE by one of the MN and the SN.
  • the RAN configures LTM for the UE by the MN (e.g., events 308, 310, 390, 312, 314, 392, 316, 318, 394, 380, 488, 490, 492, 494, 493, 480, 580, 680, 780, 880).
  • the RAN configures LTM for the UE by the SN (e.g., events 590, 592, 594, 517, 519, 688, 690, 692, 694, 693, 617, 619, 790, 792, 794, 717, 719, 888, 890, 892, 894, 893, 817, 819).
  • the RAN refrains from configuring LTM for the UE by the other of the MN and the SN.
  • Fig. 16 illustrates an example method 1600, which can be implemented by a UE (e.g., the UE 102 in Figs. 3-8B).
  • a UE e.g., the UE 102 in Figs. 3-8B.
  • the method 1600 begins at block 1602, where the UE transmits a first LTM capability of the UE for a first CG to a RAN.
  • the UE transmits a second LTM capability of the UE for LTM for a second CG to the RAN.
  • the UE receives one or more LTM configurations for the first CG from the RAN capability (e.g., events 316, 318, 394, 380, 494, 480, 580, 680, 780, 880).
  • the UE receives one or more LTM configurations for the second CG from the RAN (e.g., events 594, 517, 519, 694, 617, 619, 794, 717, 719, 894, 817, 819).
  • Fig. 17 illustrates an example method 1700, which can be implemented by a UE (e.g., the UE 102 in Figs. 3-8B).
  • a UE e.g., the UE 102 in Figs. 3-8B.
  • the method 1700 begins at block 1702, where the UE receives a UE capability enquiry message from a RAN.
  • the UE determines whether the UE supports LTM for a first CG. If the UE determines that the UE supports LTM for a first CG at block 1704, the flow proceeds to blocks 1706.
  • the UE includes an LTM capability for the first CG in a UE capability information message. Otherwise, if the UE determines that the UE does not support LTM for the first CG at block 1704, the flow proceeds to block 1708.
  • the flow proceeds to block 1708 from block 1706 as well as block 1704.
  • the UE determines whether the UE supports LTM for a second CG.
  • the flow proceeds to block 1710.
  • the UE includes an LTM capability for the second CG in the UE capability information message. Otherwise, if the UE determines that the UE does not support LTM for the second CG at block 1708, the flow proceeds to block 1712. The flow proceeds to block 1712 from block 1710 as well as block 1708. At block 1712, the UE transmits the UE capability information to the RAN.
  • Fig. 18 illustrates an example method 1800, which can be implemented by a UE (e.g., the UE 102 in Figs. 3-8B).
  • a UE e.g., the UE 102 in Figs. 3-8B.
  • the method 1800 begins at block 1802, where the UE initiates a non-accessstratum (NAS) procedure.
  • the UE determines whether the UE supports LTM for a first CG or a second CG. If the UE determines that the UE does not support LTM for the first CG and the second CG at block 1804, the flow proceeds to blocks 1806.
  • the UE transmits a NAS message in the NAS procedure, indicating that not support of LTM. Otherwise, if the UE determines that the UE supports LTM for the first CG and/or the second CG at block 1804, the flow proceeds to block 1808.
  • the UE determines whether the UE supports LTM for the first CG only, the second CG only or both the first CG and the second CG. If the UE determines that the UE supports LTM for the first CG only at block 1808, the flow proceeds to block 1810.
  • the UE transmits a NAS message in the NAS procedure, indicating support of LTM for the first CG. In this case, the UE refrains from indicating support of LTM for the second CG in the NAS message at block 1810. If the UE determines that the UE supports LTM for the second CG only at block 1808, the flow proceeds to block 1812.
  • the UE transmits a NAS message in the NAS procedure, indicating support of LTM for the second CG. In this case, the UE refrains from indicating support of LTM for the first CG in the NAS message at block 1812. Otherwise, if the UE determines that the UE supports LTM for both the first CG and the second CG at block 1808, the flow proceeds to block 1814. At block 1814, the UE transmits a NAS message in the NAS procedure, indicating support of LTM for the first CG and the second CG.
  • the NAS procedure is a registration procedure, an attach procedure or a tracking area update procedure.
  • the NAS message is a registration request message, a registration complete message, an attach request message, an attach complete message, a tracking area update request message or a tracking area update complete message.
  • a configuration method in a radio access network (RAN) node comprises: receiving an indication of low-layer triggered mobility (LTM) capability of a UE, for a cell group (CG); and configuring the UE for the CG based on the indication of the LTM capability.
  • LTM low-layer triggered mobility
  • Example 2 The method of example 1, wherein the indication of the LTM capability indicates that the UE supports LTM for the CG.
  • Example 3 The method of example 1 or 2, wherein the indication of the LTM capability is received from the UE.
  • Example 4 The method of example 3, wherein the indication of the LTM capability is included in a UE capability information message.
  • Example 5 The method of example 3, wherein the indication of the LTM capability is for a particular dual connectivity (DC) band combination.
  • DC dual connectivity
  • Example 6 The method of example 1 or 2, wherein the indication of the LTM capability is received from a core network (CN).
  • CN core network
  • Example 7 The method of example 1, wherein the indication of LTM capability is an indication of the first LTM capability for the first CG; the method further comprising: receiving an indication of second LTM capability of the UE, for a second CG; and configuring the UE for the second CG based on the indication of the second LTM capability.
  • Example 8 The method of example 7, wherein the RAN node is a first RAN node; the configuring for the first CG and the configuring for the second CG are further based on a coordination information indicative of at least one of: (i) a maximum number of LTM configurations a second RAN node is allowed to configure for the first CG, or (ii) a maximum number of LTM configurations the second RAN node is allowed to configure for the second CG.
  • Example 9 The method of example 8, further comprising transmitting the coordination information to the second RAN node.
  • Example 10 The method of any of the examples 7-9, wherein: the first RAN node is a first distributed unit (DU) of a distributed base station; and the second RAN node is a second DU of the distributed base station.
  • the first RAN node is a first distributed unit (DU) of a distributed base station
  • the second RAN node is a second DU of the distributed base station.
  • the “LTM command” can be replaced by “serving cell change command”, “Layer 1/Layer 2 switching command”, “lower layer switching 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, the “DU configuration” can be replaced by “cell group configuration”. In some implementations, the “cell index” can be replaced with “serving cell index”, “LTM cell index”, “special cell (SpCell) index”, “PCell index” or “PSCell index”. In some implementations, the “serving” can be replaced by “source”. In some implementations, the “measurement report” can be replaced by “measurement result(s)”. In some implementations, the “serving cell change” can be replaced by “serving cell switch”, “LTM cell switch” or “LTM cell switch execution”. In some implementations, “early uplink synchronization” can be replaced by “early timing advance acquisition”.
  • a user device in which the techniques of this disclosure can be implemented can be any suitable device capable of wireless communications such as a smartphone, a tablet computer, a laptop computer, a mobile gaming console, a point-of-sale (POS) terminal, a health monitoring device, a drone, a camera, a media-streaming dongle or another personal media device, a wearable device such as a smartwatch, a wireless hotspot, a femtocell, or a broadband router.
  • the user device in some cases may be embedded in an electronic system such as the head unit of a vehicle or an advanced driver assistance system (ADAS).
  • ADAS advanced driver assistance system
  • the user device can operate as an internet-of-things (loT) device or a mobile-internet device (MID).
  • the user device can include one or more general-purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.
  • Modules may can be software modules (e.g., code, or machine- readable instructions stored on non-transitory machine-readable medium) or hardware modules.
  • a hardware module is a tangible unit capable of performing certain operations and may be configured or arranged in a certain manner.
  • a hardware module can comprise dedicated circuitry or logic that is permanently configured (e.g., as a special-purpose processor, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), a digital signal processor (DSP), etc.) to perform certain operations.
  • FPGA field programmable gate array
  • ASIC application-specific integrated circuit
  • DSP digital signal processor
  • a hardware module may also comprise programmable logic or circuitry (e.g., as encompassed within a general-purpose processor or other programmable processor) that is temporarily configured by software to perform certain operations.
  • programmable logic or circuitry e.g., as encompassed within a general-purpose processor or other programmable processor
  • the decision to implement a hardware module in dedicated and permanently configured circuitry, or in temporarily configured circuitry (e.g., configured by software) may be driven by cost and time considerations.
  • the techniques can be provided as part of the operating system, a library used by multiple applications, a particular software application, etc.
  • the software can be executed by one or more general-purpose processors or one or more special-purpose processors.
  • the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion.
  • a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
  • “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

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  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Databases & Information Systems (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Un nœud de réseau d'accès radio (RAN) reçoit (902), en provenance d'un équipement utilisateur (UE), une première indication de capacité de mobilité déclenchée par couche inférieure (LTM) de l'UE, pour un premier groupe de cellules (CG) ; reçoit (904), en provenance de l'UE, une seconde indication de capacité LTM de l'UE, pour un second CG ; configure (906) l'UE avec une première configuration de LTM pour le premier CG conformément à la première indication ; et configure (908) l'UE avec une seconde configuration de LTM pour le second CG conformément à la seconde indication.
PCT/US2024/048738 2023-09-26 2024-09-26 Gestion de la mobilité pour un équipement utilisateur WO2025072577A1 (fr)

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Citations (1)

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