Managing configuration in handover

Abstract

The first node of the RAN communicating with the UE in the first cell according to the first configuration; transmitting, to the UE, a message including a second configuration for accessing a second cell after the activation command; transmitting, after the transmitting and when the UE waits for an activation command, a handover message to a second node of the RAN or the CN; and releasing the second configuration.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit and priority of the filing date of the provisional U.S. Patent Application No. 63 / 377,717, entitled "MANAGING CONFIGURATIONS IN HANDOVER", filed on September 29, 2022. The entire content of this provisional application is hereby incorporated by reference in its entirety. Technical Field

[0003] This disclosure relates to wireless communication and, more particularly, to managing configurations in handover of a user equipment (UE) and a base station. Background Art

[0004] This background description is provided for the purpose of generally presenting the context of the present disclosure. The work of the currently named inventors, to the extent it is described in this background art section, and aspects that may not have been prior art at the time of filing the specification are neither expressly nor impliedly admitted to be prior art of the present disclosure.

[0005] In a telecommunication system, the packet data convergence protocol (PDCP) sub - layer of the radio protocol stack provides services such as user - plane data transfer, encryption, integrity protection, etc. For example, 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 the sequencing of protocol data units (PDUs) in the uplink direction (from the user device (also known as user equipment (UE)) to the base station) and in the downlink direction (from the base station to the UE). In addition, the PDCP sub - layer provides signaling radio bearers (SRBs) and data radio bearers (DRBs) to the radio resource control (RRC) sub - layer. Generally, in some scenarios, the UE and the base station use SRBs to exchange RRC messages and non - access stratum (NAS) messages. In further scenarios, the UE and the base station use DRBs to transmit data on the user plane.

[0006] Depending on the scenario, the UE uses several types of SRBs and DRBs. When operating in dual connectivity (DC), the cell associated with the base station operating as the master node (MN) defines the master cell group (MCG), and the cell associated with the base station operating as the secondary node (SN) defines the secondary cell group (SCG). SRB1 resources carry RRC messages that include NAS messages on a dedicated control channel (DCCH) in some cases, while SRB2 resources support RRC messages that include logged measurement information or NAS messages also on the DCCH but with a lower priority than SRB1 resources. More generally, 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 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 directly exchange RRC messages with the MN via the lower-layer resources of the MN and the SN. Further, a DRB that uses only the lower-layer resources of the MN can be referred to as an MCG DRB, a DRB that uses only the lower-layer resources of the SN can be referred to as an SCG DRB, and a DRB that uses the lower-layer resources of both the MCG and the SCG can be referred to as a split DRB.

[0007] In some scenarios, the UE concurrently utilizes the resources of multiple radio access network (RAN) nodes (e.g., base stations, or components of a distributed base station) interconnected via a backhaul. When such network nodes support different radio access technologies (RATs), this type of connection is called multi-radio dual connectivity (MR-DC). When the UE operates under MR-DC, one base station operates as the master node (MN) covering the primary cell (PCell), and another base station operates as the secondary node (SN) covering the primary secondary cell (PSCell). The UE communicates with the MN (via the PCell) and the SN (via the PSCell). In other scenarios, the UE utilizes the resources of one base station at a time. One base station and / or the UE determines that the UE should establish a radio connection with another base station. For example, one base station determines to hand over the UE to a second base station and initiates the handover process.

[0008] When a UE moves from the coverage area of one cell in the RAN to the coverage area of another cell, a serving cell change will be performed for the UE at a certain time. To perform the serving cell change, the RAN configures the UE to send layer 3 (L3) measurement results. Based on the L3 measurement results received from the UE, the RAN sends an RRC reconfiguration message for the serving cell (e.g., PCell or PSCell) change, and the RRC reconfiguration message configures a reconfiguration with synchronization (e.g., the RRC reconfiguration message includes a ReconfigurationWithSync IE). In the case where the UE operates in carrier aggregation (CA) with at least one secondary cell (SCell) and a PCell or PSCell, the RAN must release the at least one SCell due to the change of the PCell or PSCell. The serving cell change involves a complete L2 (and L1) reset, resulting in longer latency, greater overhead, and longer interruption time. Therefore, it is desirable to develop new mobility technologies to reduce the latency and overhead of serving cell changes. However, it is not clear how to reduce the latency and overhead of serving cell changes. Summary of the Invention

[0009] An example embodiment of the technology of the present disclosure is a method in a first node of the RAN, the method including: communicating with a UE in a first cell according to a first configuration; sending a message including a second configuration to the UE, the second configuration for accessing a second cell after an activation command; after the sending and when the UE is waiting for the activation command, sending a handover message to a second node or the CN of the RAN; and releasing the second configuration.

[0010] Another example embodiment of these technologies is a method implemented in a first node of the RAN, the method including: receiving a handover message from a second node or the CN of the RAN, the handover message including (i) one or more first parameters for immediate application at a user equipment (UE), and (ii) one or more second parameters for application at the UE after an activation command from the RAN; discarding the one or more second parameters; and sending a message including a configuration based on the one or more first parameters to a second node or the CN of the RAN.

[0011] Another example embodiment of these technologies is a node in the RAN, the node including processing hardware and being configured to implement one of the above methods. Brief Description of the Drawings

[0012] Figure 1Ais a block diagram of an example system in which a radio access network (RAN) and a user equipment can implement the techniques of the present disclosure for managing conditional procedures related to a secondary node (SN);

[0013] Figure 1B is an example base station including a central unit (CU) and a distributed unit (DU) that can operate in the system of Figure 1A ;

[0014] Figure 2 is Figure 1A a block diagram of an example protocol stack of a UE according to which the UE communicates with a base station; and

[0015] Figure 3 is a message flow diagram of an example scenario in which a base station configures a UE to perform lower layer procedures for a cell change operation;

[0016] Figure 4A is a message flow diagram of an example scenario in which a MN operates with a SN under DC to perform lower layer procedures for a cell change operation;

[0017] Figure 4B is a message flow diagram of an example scenario similar to the example scenario of Figure 4A but in which the MN directly configures the UE;

[0018] Figure 5A is a flowchart depicting an example method implemented in a base station, where the base station generates and sends a handover request message including a first plurality of configurations and excluding configurations for later activation;

[0019] Figure 5B is a flowchart depicting an example method similar to the example method of Figure 5A but in which the message is a handover required message;

[0020] Figure 5C is a flowchart depicting an example method similar to the example method of Figure 5A but in which the RAN node generates a handover request after releasing configurations for later activation;

[0021] Figure 5D is a flowchart depicting an example method similar to the example method of Figure 5C but in which the message is a handover required message;

[0022] Figure 6Ais a flowchart depicting an example method implemented in a base station, where the base station receives a handover request message including multiple configurations and a configuration for later activation, and generates the second multiple configuration parameters before sending the second multiple configuration parameters to another base station;

[0023] Figure 6B is a flowchart depicting an example method similar to that of Figure 6A but where the base station receives a handover request message from the core network and sends the second multiple configuration parameters to the core network;

[0024] Figure 7 is a flowchart depicting an example method implemented in a base station, where the base station determines whether to release a configuration based on whether the received container includes a configuration for later activation;

[0025] Figure 8A is a flowchart depicting an example method implemented in a base station, where the base station sends a message to the UE to handover the UE to a second cell and releases the configuration for later activation;

[0026] Figure 8B is a flowchart depicting an example method similar to that of Figure 8A but where the base station retains the configuration for later activation;

[0027] Figure 9 is a flowchart depicting an example method implemented in a base station, where the base station determines whether to include a release indication in the message to the base station based on the determination of whether to release the configuration for later activation;

[0028] Figure 10A is a flowchart depicting an example method implemented in a UE, where the UE performs a handover to a second cell and releases the configuration for later activation;

[0029] Figure 10B is a flowchart depicting an example method similar to that of Figure 10A but where the UE retains the configuration for later activation;

[0030] Figure 10C is a flowchart depicting an example method similar to that of Figure 10A and Figure 10B but where the UE determines whether to release or retain the configuration based on whether the received message includes a release indication; and

[0031] Figure 11 is a flowchart depicting an example method implemented in a base station, where the base station determines whether to send a configuration for later activation to the UE based on whether the second cell is operated by the base station. Detailed Description

[0032] Figure 1A FIG. 100 illustrates an example wireless communication system in which a communication device may 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 is initially connected to the base station 104. In some scenarios, the base station 104 may perform SN addition to configure the UE 102 to operate under dual connectivity (DC) with the base station 104 and the base station 106. The base stations 104 and 106 operate as the MN and SN of the UE 102, respectively.

[0033] In various configurations of the wireless communication system 100, the base station 104 may be implemented as a master eNB (MeNB) or a master gNB (MgNB), and the base station 106 may be implemented as a secondary gNB (SgNB). The UE 102 may communicate with the base station 104 and the base station 106 via the same RAT such as EUTRA or NR or different RATs. When the base station 104 is a MeNB and the base station 106 is an SgNB, the UE 102 may be in EUTRA-NR DC (EN-DC) with the MeNB and the SgNB.

[0034] In some cases, the MeNB or the SeNB is implemented as an ng-eNB instead of an eNB. When the base station 104 is a master ng-eNB (Mng-eNB) and the base station 106 is an SgNB, the UE 102 may be in next generation (NG) EUTRA-NR DC (NGEN-DC) with the Mng-eNB and the SgNB. When 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. When the base station 104 is an MgNB and the base station 106 is a secondary ng-eNB (Sng-eNB), the UE 102 may be in NR-EUTRA DC (NE-DC) with the MgNB and the Sng-eNB.

[0035] In a scenario where the UE 102 handovers from the base station 104 to the base station 106, the base stations 104 and 106 operate as a source base station (S-BS) and a target base station (T-BS), respectively. For example, before the handover, the UE 102 may operate under DC with the base station 104 and an additional base station ( Figure 1A not shown in FIG. 100). After the handover is completed, the UE 102 may continue to operate under DC with the base station 106 and the additional base station, or operate under single connectivity (SC) with the base station 106. In this case, the base stations 104 and 106 operate as a source MN (S-MN) and a target MN (T-MN), respectively.

[0036] The core network (CN) 110 can be an evolved packet core (EPC) 111 or a fifth-generation core (5GC) 160, both of which are depicted in Figure 1A FIG. 1. The base station 104 can be an eNB that supports the S1 interface for communication with the EPC 111, an ng-eNB that supports the NG interface for communication with the 5GC 160, or a gNB that supports the NR radio interface and the NG interface for communication with the 5GC 160. In order to directly exchange messages with each other during the scenarios discussed below, the base stations 104 and 106 can support the X2 or Xn interface. Among other components, the EPC 111 can include a serving gateway (SGW) 112, a mobility management entity (MME) 114, and a packet data network gateway (PGW) 116. The SGW 112 is generally configured to transport user-plane packets related to audio calls, video calls, Internet traffic, etc., and 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., the Internet network and / or the Internet Protocol (IP) Multimedia Subsystem (IMS) network). The 5GC 160 includes a user plane function (UPF) 162, an access and mobility management (AMF) 164, and / or a session management function (SMF) 166. The UPF 162 is generally configured to transport 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, and the SMF 166 is configured to manage PDU sessions.

[0037] As Figure 1A shown, the base station 104 supports the cell 124A, and the base station 106 supports the cell 126. The cells 124A and 126 can partially overlap, such that the UE 102 can communicate with the base stations 104 and 106 under DC, where one of the base stations 104 and 106 is the MN and the other is the SN. The base station 104 can support additional cells such as cells 124B and 124C, and the base station 106 can support additional cells ( Figure 1A not shown in FIG. 2). The cells 124A, 124B, and 124C can partially overlap, such that the UE 102 can communicate with the base station 104 in carrier aggregation (CA). The base station 104 can operate the cells 124A, 124B, and 124C via one or more transmit and receive points (TRP). More specifically, when the UE 102 operates with the base stations 104 and 106 under DC, one of the base stations 104 and 106 operates as a MeNB, Mng-eNB, or MgNB, and the other operates as an SgNB or Sng-eNB.

[0038] Generally, the wireless communication network 100 may include any suitable number of base stations that support NR cells and / or EUTRA cells. More specifically, the EPC 111 or 5GC 160 may be connected to any suitable number of base stations that support NR cells and / or EUTRA cells. Although the examples below specifically relate to particular CN types (EPC, 5GC) and RAT types (5G NR and EUTRA), generally, the techniques of the present disclosure may also be applicable to other suitable radio access and / or core network technologies, such as sixth generation (6G) radio access and / or 6G core network or 5G NR-6G DC.

[0039] Continuing to refer Figure 1A , the base station 104 is equipped with processing hardware 130, which may include one or more general-purpose processors (e.g., CPUs) and a non-transitory computer-readable memory that stores instructions executed by the one or more general-purpose processors. Additionally or alternatively, the processing hardware 130 may include a dedicated processing unit. The processing hardware 130 may include a PHY controller 132, which is configured to transmit data and control signals 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., cells 124A, 124B, and / or 124C) and / or one or more TRPs. The PHY controller 132 is also configured to transmit data and control signals on physical downlink (DL) channels and DL reference signals with one or more user devices via one or more cells (e.g., cells 124A, 124B, and / or 124C) and / or one or more TRPs. The processing hardware 130 in an example implementation includes a MAC controller 134, which is configured to perform MAC functions with one or more user devices. MAC functions include random access (RA) procedures, managing UL timing advance for one or more user devices, and / or communicating UL / DL MAC PDUs with one or more user devices. The processing hardware 130 may further include an RRC controller 136 to implement procedures and messaging at the RRC sublayer of the protocol communication stack. For example, the RRC controller 132 may be configured to support RRC messaging associated with handover procedures and / or support necessary operations when the base station 104 operates as an MN with respect to an SN or as an SN with respect to an MN. The base station 106 may include processing hardware 140 similar to the processing hardware 130. In particular, components 142, 144, and 146 may be similar to components 132, 134, and 136, respectively.

[0040] The UE 102 is equipped with processing hardware 150, which may include one or more general-purpose processors such as a CPU and a non-transitory computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors, and / or a dedicated processing unit. The PHY controller 152 is also configured to receive data and control signals on physical DL channels and / or DL reference signals with the base station 104 or 106 via one or more cells (e.g., cells 124A, 124B, 124C, and / or 126) and / or one or more TRPs. The PHY controller 152 is also configured to transmit data and control signals on physical UL channels and / or UL reference signals with the base station 104 or 106 via one or more cells (e.g., cells 124A, 124B, 124C, and / or 126) and / or one or more TRPs. The processing hardware 150 in an example implementation includes a MAC controller 154, which is configured to perform MAC functions with the base station 104 or 106. For example, the MAC functions include random access procedures, managing UL timing advance for one or more user devices, and communicating UL / DL MAC PDUs with the base station 104 or 106. The processing hardware 150 may further include an RRC controller 156 to implement procedures and messaging at the RRC sublayer of the protocol communication stack.

[0041] In operation, the UE 102 under DC may use radio bearers (e.g., DRB or SRB) that terminate at the MN 104 or the SN 106 at different times. When communicating on a radio bearer in the uplink (UL) (from the UE 102 to the base station) and / or downlink (from the base station to the UE 102) direction, the UE 102 may apply one or more security keys.

[0042] Figure 1BDepicts an example distributed implementation of a base station such as base station 104 or 106. In this implementation, the base station may include a Centralized Unit (CU) 172 and one or more Distributed Units (DUs) 174. The CU 172 is equipped with processing hardware, which may include one or more general-purpose processors such as a CPU and a non-transitory computer-readable memory storing machine-readable instructions executable on one or more general-purpose processors, and / or a dedicated processing unit. In one example, the CU 172 is equipped with processing hardware 130. In another example, the CU 172 is equipped with processing hardware 140. In an example implementation, the processing hardware 140 includes an SN RRC controller 142, which is 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, which may include one or more general-purpose processors such as a CPU and a non-transitory computer-readable memory storing machine-readable instructions executable on one or more general-purpose processors, and / or a dedicated processing unit. In some examples, in an example implementation, the processing hardware includes: a Media Access Control (MAC) controller, which is configured to manage or control one or more MAC operations or procedures (e.g., random access procedure); and a Radio Link Control (RLC) controller, which is configured to manage or control one or more RLC operations or procedures when the base station 106 operates as an MN or SN. The processing hardware may further include a Physical Layer controller, which is configured to manage or control one or more Physical Layer operations or procedures.

[0043] Next, Figure 2 Illustrates in a simplified manner the radio protocol stack according to which the UE 102 may communicate with an eNB / ng-eNB or gNB. Each of the base stations 104 or 106 may be an eNB / ng-eNB or gNB.

[0044] The physical layer (PHY) 202A of EUTRA provides transport channels to the EUTRA media access control (MAC) sublayer 204A, which in turn provides logical channels to the EUTRA radio link control (RLC) sublayer 206A, and the EUTRA RLC sublayer in turn provides RLC channels to the EUTRA PDCP sublayer 208 and in some cases to the NR PDCP sublayer 210. Similarly, the PHY 202B of NR provides transport channels to the NR MAC sublayer 204B, which in turn provides logical channels to the NR RLC sublayer 206B, and the NR RLC sublayer 206B in turn provides RLC channels to the NR PDCP sublayer 210. In some implementations, the UE 102 supports both the EUTRA and NR stacks to support handover between EUTRA and NR base stations and / or DC over the EUTRA and NR interfaces. Additionally, as Figure 2 shown in A, the UE 102 may support the layering of NR PDCP 210 over EUTRA RLC 206A.

[0045] The EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 receive packets (e.g., from an Internet protocol (IP) layer that is directly or indirectly layered above the PDCP layer 208 or 210) that may be referred to as service data units (SDUs), and output packets (e.g., output to the RLC layer 206A or 206B) that may be referred to as protocol data units (PDUs). For simplicity, this disclosure refers to both SDUs and PDUs as "packets" except where the differences between SDUs and PDUs are relevant.

[0046] For example, on the control plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 provide SRBs to exchange radio resource control (RRC) messages. On the user plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 provide DRBs to support data exchange.

[0047] When the UE 102 operates under EUTRA / NR DC (EN-DC) with the base station 104 operating as a MeNB and the base station 106 operating as an SgNB, the network may provide the UE 102 with a bearer terminated at the MN using EUTRA PDCP 208, or a bearer terminated at the MN using NR PDCP 210. In various scenarios, the network may also provide the UE 102 with a bearer terminated at the SN using only NR PDCP 210. The bearer terminated at the MN may be an MCG bearer or a split bearer. The bearer terminated at the SN may be an SCG bearer or a split bearer. The bearer terminated at the MN may be an SRB (e.g., SRB1 or SRB2) or a DRB. The bearer terminated at the SN may be an SRB (e.g., SRB) or a DRB.

[0048] Next, several example scenarios where a base station operating in a Figure 1A system sends a configuration to the UE 102 and later activates the configuration for communication between the UE 102 and the base station. In general, Figure 3 , Figure 4A and Figure 4B similar events in Figure 4A and Figure 4B are labeled with similar reference numbers (e.g., event 316 is similar to the event 416 in Figure 4A and Figure 4B ), and the differences will be discussed below as appropriate. In addition to the differences shown in the figures and discussed below, any of the alternative implementations discussed for a particular event (e.g., for message passing and handling) may be applicable to the events labeled with similar reference numbers in other figures.

[0049] First, referring to Figure 3 , in scenario 300, the UE 102 initially communicates 302 with the base station 104 on cell 124A. In some implementations, the UE 102 in carrier aggregation (CA) communicates with the base station 104 on cell 124A and other cells using a first configuration. In other implementations, the UE 102 communicates with the base station 104 only on cell 124A. In some implementations, the UE 102 communicates with the base station 104 on cell 124A and / or other cells via one or more TRPs. In some implementations, cell 124A is a PCell. In such cases, the other cells include SCell and / or additional cells associated with the PCell or SCell. In other implementations, cell 124A is an SCell, and one of the other cells is a PCell. In such cases, the remaining cells include SCell and / or additional cells associated with the PCell or SCell.

[0050] In some implementations, in event 302, the UE 102 transmits UL PDUs and / or UL control signals to the base station 104 on cell 124A and / or other cells via one or more TRPs. In some implementations, the UE 102 conveys UL PDUs and / or DL PDUs to the base station 104 via radio bearers that may include SRBs and / or DRBs. In further implementations, the base station 104 configures radio bearers for the UE 102. In some implementations, the UL control signals include UL control information, channel state information, hybrid automatic repeat request (HARQ) acknowledgments (ACKs), HARQ negative ACKs, scheduling requests, and / or sounding reference signals. Similarly, in further implementations, the UE 102 receives DL PDUs and / or DL control signals from the base station 104 on cell 124A and / or other cells via one or more TRPs. In some implementations, the DL control signals include downlink control information (DCI) and reference signals (e.g., synchronization signal blocks, channel state information reference signals (CSI-RSs), and / or tracking reference signals). In further implementations, the base station 104 transmits DCI on the physical downlink control channel (PDCCH) monitored by the UE 102 on cell 124A and / or other cells via one or more TRPs.

[0051] In some implementations, the first configuration includes physical layer configuration parameters, MAC configuration parameters, RLC configuration parameters, PDCP configuration parameters, measurement configuration parameters, and / or radio bearer configuration parameters. In some implementations, the first configuration includes configuration parameters in the CellGroupConfig IE or the CellGroupConfig IE (e.g., defined in 3GPP specification 38.331). In some implementations, the first configuration includes the CSI-MeasConfig IE, the MeasConfig IE, and / or the RadioBearer Config IE (e.g., as defined in 3GPP specification 38.331), or includes configuration parameters in the CSI-MeasConfig IE, the MeasConfig IE, and / or the RadioBearerConfig IE. In some implementations, the UE 102 receives configuration parameters from the base station 104. In other implementations, the UE 102 receives a part of the configuration parameters from a base station other than the base station 104 and receives the remaining part of the configuration parameters from the base station 104.

[0052] When communicating with base station 104, UE 102 sends 304 at least one measurement report to base station 104. In some implementations, the at least one measurement report includes layer 1 (L1) measurement reports and / or layer 3 (L3) measurement reports for at least one serving cell and / or at least one non-serving cell of UE 102. The at least one serving cell includes cell 124A and / or other cells (e.g., Figure 1A cell 124D not shown in the figure), and the at least one non-serving cell includes cell 124B and / or cell 124C. In some implementations, the first configuration includes at least one measurement configuration that configures UE 102 to perform measurements and report the measurement results. In some implementations, UE 102 receives one or more RRC messages (e.g., RRCReconfiguration messages) including at least one measurement configuration from base station 104 in event 302. According to the at least one measurement configuration, UE 102 performs measurements and sends 304 at least one measurement report to base station 104. In some implementations, the at least one measurement configuration includes an L3 measurement configuration (e.g., MeasConfig IE) and / or an L1 measurement configuration. For example, the L1 measurement configuration (e.g., CSI-MeasConfig IE) includes CSI resource configuration (e.g., CSI-ResourceConfig IE) and / or CSI report configuration (e.g., CSI-ReportConfig IE). UE 102 sends an L3 measurement report to base station 104 according to the L3 measurement configuration. UE 102 sends an L1 measurement report to base station 104 according to the L1 measurement configuration. In some implementations, the at least one measurement configuration includes a new type of measurement configuration for fast serving cell change (e.g., a new RRC IE defined in 3GPP specification 38.331 v18.0.0 and / or later versions). For example, the new type of measurement configuration includes CSI resource configuration (e.g., CSI-ResourceConfig IE) and / or a new type of report configuration. In such implementations, the at least one measurement report includes a new type of measurement report associated with the new type of measurement configuration. UE 102 sends the new type of measurement report to base station 104 according to the new type of measurement configuration. In some implementations, each of the new type of report configurations includes a trigger event configuration that configures a trigger event to trigger UE 102 to send a new type of measurement report. If UE 102 detects the trigger event, UE 102 sends the new type of measurement report to base station 104.

[0053] In some implementations, the L1 measurement report includes at least one L1 measurement result. In some implementations, at least the L1 measurement result includes at least one L1 reference signal received power (L1-RSRP) value and / or at least one L1 signal-to-interference-plus-noise ratio (L1-SINR) value. In some implementations, for each L1 measurement report in the L1 measurement report, the UE 102 sends a PUCCH transmission including the L1 measurement report to the base station 104. That is, the UE 102 sends each L1 measurement report in the L1 measurement report to the base station 104 on the PUCCH. In other implementations, for each L1 measurement report in the L1 measurement report, the UE 102 sends a PUSCH transmission including the L1 measurement report to the base station 104. That is, the UE 102 sends each L1 measurement report in the L1 measurement report to the base station 104 on the PUSCH. In still other implementations, the UE 102 sends a part of the L1 measurement report to the base station 104 on the PUCCH and sends the remaining part of the L1 measurement report to the base station on the physical uplink shared channel (PUSCH). That is, for each L1 measurement report in a part of the L1 measurement report, the UE 102 sends a PUCCH transmission including the L1 measurement report to the base station 104, and for each L1 measurement report in the remaining part of the L1 measurement report, the UE 102 sends a PUSCH transmission including the L1 measurement report to the base station 104. In some implementations, each L1 measurement report in the L1 measurement report is part of the channel state information (CSI) (i.e., a CSI component) or CSI. In some implementations, the UE 102 includes other CSI components in the above PUCCH transmission and / or PUSCH transmission. In some implementations, the other CSI components include, such as, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a CSI-RS resource indicator (CRI), a synchronization signal (SS) / physical broadcast channel (PBCH) resource block indicator (SSBRI), a layer indicator (LI), and / or a rank indicator (RI).

[0054] In some implementations, each L3 measurement report in the L3 measurement reports may include at least one L3 measurement result. In some implementations, the at least one L3 measurement result includes at least one RSRP (value) and / or at least one SINR (value). In some implementations, UE 102 sends each L3 measurement report in the L3 measurement reports to the base station 104 on the PUSCH. In some implementations, each L3 measurement report in the L3 measurement reports is an RRC message (e.g., MeasurementReport message). In some implementations, each L3 measurement configuration in the L3 measurement configurations includes a specific measurement identifier (e.g., measId), and each L3 measurement report in the L3 measurement reports includes the specific measurement identifier in the specific L3 measurement configuration. In a further implementation, when the base station 104 receives an L3 measurement report including a measurement identifier and an L3 measurement result from the UE 102, the base station 104 determines that the L3 measurement report is associated with the L3 measurement configuration identified by the measurement identifier.

[0055] In some alternative implementations, for each measurement report in at least one measurement report (e.g., L1 measurement report, L3 measurement report, and / or new type measurement report), in event 304, UE 102 sends a MAC control element (CE) including the measurement report to the base station 104. To send the MAC CE, in event 304, UE 102 generates one or more MAC PDUs for the base station 104, each MAC PDU including one or more MAC CEs in the MAC CE.

[0056] In some implementations, UE 102 performs measurements on one or more reference signals according to at least one measurement configuration. Depending on the implementation, the one or more reference signals include one or more synchronization signals (SS) / physical broadcast channel (PBCH) resource blocks (SSB) and / or one or more CSI-RS. UE 102 obtains at least one L1 measurement result and / or at least one L3 measurement result from the measurements. The base station 104 sends one or more reference signals on cells 124A and 124B and in a further implementation on cells 124C and / or other cells.

[0057] After receiving one or some of the measurement reports in event 304 (e.g., in response thereto), base station 104 determines to prepare cell 124B for UE 102. In some implementations, base station 104 determines to prepare cell 124B for UE 102 because at least one measurement report indicates that cell 124B can be used by base station 104 to communicate with UE 102. For example, if at least one measurement report indicates that the signal strength and / or quality of cell 124B is higher than a first predetermined threshold and / or better (e.g., higher) than cell 124A, then base station 104 determines to prepare cell 124B for UE 102. Alternatively, regardless of whether a measurement report is received from UE 102, base station 104 determines to prepare cell 124B for UE 102.

[0058] In response to the determination to prepare cell 124B, base station 104 generates a second configuration (referred to herein as configuration 1) that configures cell 124B, generates an RRC reconfiguration message (e.g., RRCReconfiguration message) that includes configuration 1, and transmits 306 the RRC reconfiguration message to UE 102. In response, UE 102 transmits 308 an RRC reconfiguration complete message (e.g., RRCReconfigurationComplete message) to base station 104. In some implementations, base station 104 performs security protection (e.g., integrity protection and / or encryption) on the RRC reconfiguration message. For example, base station 104 generates a message authentication code (MAC-I) for integrity 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 in event 306 a PDCP PDU that includes the encrypted RRC reconfiguration message and the encrypted MAC-I to UE 102. When UE 102 receives the PDCP PDU from base station 104 in event 306, UE 102 decrypts the encrypted RRC reconfiguration and the encrypted MAC-I to obtain the RRC reconfiguration message and the MAC-I, and verifies whether the MAC-I is valid. If UE 102 verifies that the MAC-I is invalid, then UE 102 discards or ignores the RRC reconfiguration message. In some implementations, UE 102 performs an RRC connection reconstruction procedure in response to an invalid MAC-I. Otherwise, in some implementations, if UE 102 verifies that the MAC-I is valid, then UE 102 processes the RRC reconfiguration. UE 102 refrains from applying (i.e., executing) configuration 1 until it receives a configuration activation command (e.g., event 312) that activates configuration 1.

[0059] In some implementations, the base station 104 includes (e.g., as defined in 3GPP specification 38.331 v18.0.0 and / or later versions, 3GPP 6G specifications, etc.) a field or IE in the RRC reconfiguration message for event 306 to indicate to the UE 102 not to immediately apply Configuration 1, so that the UE waits for a subsequent activation command (see, for example, the discussion of event 312 below). In some implementations, the field or IE is an indicator. If the RRC reconfiguration message for event 306 includes the indicator, the UE 102 avoids immediately applying Configuration 1. Otherwise, if the RRC reconfiguration message for event 306 does not include the indicator, the UE 102 immediately applies Configuration 1. In other implementations, the field or IE is a container (e.g., the first container and / or the second container described below). For example, the UE 102 receives an RRC reconfiguration message (e.g., the RRC reconfiguration message for event 306), which includes a configuration (e.g., Configuration 1). If the configuration is included in the container, the UE 102 avoids immediately applying the configuration. Otherwise, if the configuration is not included in the container, the UE 102 immediately applies the configuration.

[0060] In some implementations, the base station 104 generates a first container including Configuration 1, includes the first container in the RRC reconfiguration message, and sends the RRC reconfiguration message to the UE 102 in event 306. In some implementations, the first container is a first addition or modification list (e.g., ConfigToAddModList IE, CellConfigToAddModList IE, MobilityToAddModList IE, MobilityConfigToAddModList IE, or CellGroupConfigToAddModList IE). The base station 104 includes Configuration 1 in the first element (referred to herein as Element 1) of the first addition or modification list. For example, Element 1 can be an addition or modification IE (e.g., ConfigToAddMod IE, CellConfigToAddMod IE, MobilityToAddMod IE, MobilityConfigToAddMod IE, or CellGroupConfigToAddMod IE). In some implementations, when the UE 102 receives the first addition or modification list, the UE 102 stores the first addition or modification list (e.g., in a variable in random access memory (RAM)).

[0061] In some implementations, the base station 104 includes a first ID (referred to herein as ID 1) for identifying Configuration 1 in the RRC reconfiguration message. In some implementations, the base station 104 includes ID 1 in the first container or element 1. In some implementations, the base station 104 assigns ID 1 to Configuration 1.

[0062] In some implementations, Configuration 1 includes multiple configurations for the UE 102 to communicate with the base station 104 on cell 124B. In some implementations, the multiple configurations include physical layer configuration parameters (e.g., PhysicalCellGroupConfigIE), MAC layer configuration parameters (e.g., MAC-CellGroupConfig IE), and / or RLC configuration parameters (e.g., RLC-Bearer Config IE). In some further implementations, the multiple configurations include special cell configurations (e.g., SpCellConfig IE) and / or one or more SCell configurations (e.g., SCellConfig IE).

[0063] In some implementations, the base station 104 includes a random access configuration in Configuration 1. In other implementations, the base station 104 does not include a random access configuration in Configuration 1. In some implementations, if cell 124A and cell 124B are out of sync, the base station 104 determines to include a random access configuration in Configuration 1. Otherwise, if cell 124A and cell 124B are in sync, the base station 104 determines not to include a random access configuration in Configuration 1. In other implementations, if the base station 104 determines that the UE 102 has not synchronized with cell 124B in the UL, the base station 104 determines to include a random access configuration in Configuration 1. Otherwise, if the base station 104 determines that the UE 102 has already synchronized with cell 124B in the UL, the base station 104 determines not to include a random access configuration in Configuration 1. If Configuration 1 includes a random access configuration, the UE 102 performs a random access procedure according to the random access configuration in event 316, as described below. Otherwise, if Configuration 1 does not include a random access configuration, the UE 102 skips the random access procedure of event 316 in response to Configuration 1 excluding the random access configuration.

[0064] In some implementations, the base station 104 includes a random access configuration in Configuration 1 regardless of whether cells 124A and 124B are synchronized. In some implementations, if cells 124A and 124B are synchronized, the base station 104 determines to include a first indication in Configuration 1 that configures the UE 102 not to perform a random access procedure on cell 124B. Otherwise, if cell 124A is not synchronized with cell 124B, the base station 104 determines not to include the first indication in Configuration 1. In other implementations, if the base station 104 determines that the UE 102 has synchronized with cell 124B in the UL, the base station 104 determines to include the first indication in Configuration 1. Otherwise, if the base station 104 determines that the UE 102 has not synchronized with cell 124B in the UL, the base station 104 determines not to include the first indication in Configuration 1. If Configuration 1 includes the first indication, the UE 102 skips the random access procedure for event 316 according to or in response to the first indication. Otherwise, if Configuration 1 does not include the first indication, the UE 102 performs a random access procedure according to the random access procedure in event 316 in response to Configuration 1 not including the first indication, as described below.

[0065] In some implementations, base station 104 includes a reconfiguration with a synchronization configuration (e.g., ReconfigurationWithSync IE) in configuration 1 or a special cell configuration. In other implementations, base station 104 does not include a reconfiguration with a synchronization configuration (e.g., ReconfigurationWithSync IE) in configuration 1 or a special cell configuration. In some implementations, if cell 124A and cell 124B are not synchronized, base station 104 determines to include a reconfiguration with a synchronization configuration in configuration 1. Otherwise, if cell 124A and cell 124B are synchronized, base station 104 determines not to include a reconfiguration with a synchronization configuration in configuration 1. In other implementations, if base station 104 determines that UE 102 has not yet synchronized with cell 124B in the UL, base station 104 determines to include a reconfiguration with a synchronization configuration in configuration 1. Otherwise, if base station 104 determines that UE 102 has already synchronized with cell 124B in the UL, base station 104 determines not to include a reconfiguration with a synchronization configuration in configuration 1. In some implementations, if configuration 1 includes a reconfiguration with a synchronization configuration, UE 102 performs a random access procedure in event 316 in response to or according to the reconfiguration with a synchronization configuration, as described below. Otherwise, if configuration 1 does not include a reconfiguration with a synchronization configuration, UE 102 skips the random access procedure for event 316. In some implementations, base station 104 includes the cell identifier (ID) of cell 1 (i.e., cell 124B) in configuration 1 (i.e., cell ID 1). In some implementations, cell ID 1 is a physical cell ID (PCI). In some further implementations, configuration 1 includes a cell index (e.g., serving cell index) that indexes cell ID 1 or cell 124B.

[0066] In some implementations, after receiving one or some of the measurement reports of event 304 (e.g., in response thereto), base station 104 determines to prepare other cells of base station 104 for UE 102. In some implementations, base station 104 determines to prepare other cells because at least one of the measurement reports indicates that the other cells can be used by base station 104 to communicate with UE 102. In further implementations, the other cells include cell 124C and / or cells other than cells 124A, 124B, and 124C. In some implementations, if the L3 measurement report indicates that the signal strength and / or quality of a particular cell among the other cells is higher than a corresponding predetermined threshold and / or better (e.g., higher) than cell 124A, then base station 104 determines to prepare the particular cell for UE 102. In other implementations, if the L1 measurement report or a new type of measurement report indicates that the signal strength and / or quality of a particular cell among the other cells is higher than a first predetermined threshold and / or better (e.g., higher) than cell 124A, then base station 104 determines to prepare the particular cell for UE 102. In some implementations, the corresponding predetermined threshold of the other cells is different from the first predetermined threshold. In further implementations, the corresponding predetermined threshold of the other cells is the same as the first predetermined threshold. In some implementations, the corresponding predetermined thresholds of the other cells are the same or different. Alternatively, regardless of whether a measurement report is received from UE 102, base station 104 determines to prepare other cells for UE 102.

[0067] In response to determining to prepare other cells, base station 104 generates configurations 2, …, N and includes configurations 2, …, N in a first container, each configuration configuring a particular cell of base station 104. "N" is an integer and greater than zero. For example, "N" is 2, 4, 6, 8, 10, 12, 14, or 16. Examples and implementations of configuration 1 can be applied to configurations 2, …, N. In some implementations, base station 104 assigns IDs 2, …, N that respectively identify configurations 2, …, N and includes IDs 2, …, N in the first container. For example, base station 104 includes IDs 2, …, N and configurations 2, …, N in elements 2, …, N of the first addition or modification list. In some alternative implementations, base station 104 generates a second container that includes configurations 2, …, N or elements 2, …, N without using the first container. Then, base station 104 sends an additional RRC reconfiguration message that includes the second container to UE 102. In response, UE 102 sends an additional RRC reconfiguration complete message to base station 104.

[0068] In some implementations, the second container is a second addition or modification list (e.g., ConfigToAddModListIE, CellConfigToAddModList IE, MobilityToAdd ModList IE, MobilityConfigToAddModList IE, or CellGroupConfigToAdd ModList IE), and each of elements 2, …, element N is an addition or modification IE (e.g., ConfigToAddMod IE, ReconfigToAddMod IE, CellConfigTo AddMod IE, MobilityToAddMod IE, MobilityConfigToAddMod IE, or CellGroupConfigToAddMod IE). In further implementations, when UE 102 receives the second addition or modification list, UE 102 stores the second addition or modification list together with the first addition or modification list (e.g., in a variable in the RAM). In some implementations, the base station 104 includes cell IDs 2, …, N in configurations 2, …, N, respectively. The cell IDs 2, …, N identify cells 2, …, N, respectively. In some implementations, each of the cell IDs is a PCI. In some further implementations, configurations 2, …, N include cell indices 2, …, N (e.g., serving cell indices) that index the cell IDs 2, …, N or cells 2, …, N, respectively.

[0069] In some implementations, each of configurations 1 and / or 2, …, N is a CellGroupConfig IE. In such implementations, the following is an example structure of the first or second addition or modification list (e.g., CellGroupConfigToAddModList IE), and CellGroupConfigToAddMod IE is an element of the first or second addition or modification list.

[0070] In some implementations, the base station 104 sends a release list to the UE 102 to release one or more configurations among configurations 1, …, N. For example, the base station 104 sends an RRC reconfiguration message including the release list to the UE 102. In response, the UE 102 sends an RRC reconfiguration complete message to the base station 104. In some implementations, the base station 104 includes the IDs of one or more configurations in the release list to indicate the one or more configurations to be released. The UE 102 identifies the one or more configurations based on the IDs and releases the one or more configurations in response to the release list. In other implementations, the base station 104 sends an empty or configuration-free third addition or modification list to the UE 102 to release all of the configurations 1, …, N. In some implementations, the base station 104 sends an RRC reconfiguration message including the third addition or modification list to the UE 102. In response, the UE 102 sends an RRC reconfiguration complete message to the base station 104. The UE 102 releases all of the configurations 1, …, N in response to the third addition or modification list.

[0071] Example implementation 1

[0072]

[0073] For example, the first addition or modification list is the first CellGroupConfigToAddModList IE, and the second addition or modification list is the second CellGroupConfigToAddModList IE. Element 1 is CellGroupConfigToAddMod IE 1, and elements 2, …, N are CellGroupConfigToAddMod IE2, …, N respectively. ID 1 and configuration 1 are the ConfigId and CellGroupConfig IE in CellGroupConfigToAddMod IE 1 respectively. ID 2, …, N and configuration 2, …, N are the ConfigId and CellGroupConfig IE in CellGroupConfigToAddMod IE2, …, N respectively. In some implementations, the first CellGroupConfigToAddModList IE includes CellGroupConfigToAddMod IE 1, and the second CellGroupConfigToAddModList IE includes CellGroupConfig ToAddMod IE 2, …, N. In further implementations, the first CellGroupConfigToAddModList IE includes CellGroupConfigToAddModIE 1, …, N.

[0074] In some implementations, the release list is the CellGroupConfigToReleaseList IE. In further implementations, the base station 104 includes one or more ConfigIDIEs in the CellGroupConfigToReleaseList IE to release one or more of the CellGroupConfigToAddMod IEs in CellGroupConfigToAddMod IE 1, …, N. One or more CellGroupConfigToAddMod IEs are identified by one or more ConfigID IEs.

[0075] Example implementation 2

[0076] Example implementation 2 is similar to example implementation 1, except that the CellGroupConfigToAddModIE does not include a ConfigId.

[0077]

[0078] In some implementations, IDs 1, ……, N are implicitly indicated by the order of CellGroupConfigToAddMod IEs 1, ……, N in the first or second CellGroupConfigToAddModList. For example, CellGroupConfigToAddMod IE 1 is the first IE in the first CellGroupConfigToAddModList IE, which implicitly indicates that ID 1 has a value of X. X can be zero or one. If the first CellGroupConfigToAddModList IE includes CellGroupConfigToAddMod IEs 1, ……, N in order, then IDs 1, ……, N have values X, X + 1, ……, X+(N - 1). In some implementations, if base station 104 sends the second CellGroupConfigToAddModList IE to UE 102, then UE 102 and base station 104 replace the first CellGroupConfigToAddModList IE with the second CellGroupConfigToAddModList IE. If the second CellGroupConfigToAddModList IE includes CellGroupConfigToAddMod IEs 2, ……, N in order, then IDs 2, ……, N are values X, X + 1, ……, X+N - 2. If the second CellGroupConfigToAddModList IE includes CellGroupConfigToAddMod IEs 1, ……, N in order, then IDs 1, ……, N are values X, X + 1, ……, X+N - 1. In some alternative implementations, IDs 1, ……, N are cell IDs 1, ……, N.

[0079] In some implementations, base station 104 sends a CellGroupConfigToAddModList IE that includes zero CellGroupConfigToAddMod IEs to release all CellGroupConfigToAddMod IEs 1, ……, N.

[0080] In exemplary implementation manners 1 and 2, "CellGroupConfigToAddModList", "CellGroupConfigToAddMod", "configId", "ConfigId", "cellGroupConfig", "CellGroupConfigToReleaseList", and "maxNrofConfig Cells" are merely exemplary and should not be regarded as limiting the scope and application of the present invention.

[0081] In other implementation manners, each of Configuration 1 and / or Configuration 2, ……, N is an RRCReconfiguration message. In such implementation manners, the following (i.e., exemplary implementation manners 3 to 6) are example structures of the first or second addition or modification list.

[0082] Exemplary implementation manner 3

[0083] In exemplary implementation manner 3, the first or second addition or modification list is a CondReconfigToAddModList-r16 IE (e.g., as defined in 3GPP specification 38.331 of version 16), and the CondReconfigToAddMod IE is an element of this list.

[0084]

[0085] For example, the first addition or modification list is the first CondReconfigToAddModList-r16 IE and the second CondReconfigToAddModList-r16 IE. Element 1 is the CondReconfigToAddMod-r16 IE 1, and elements 2, …, N are the CondReconfigToAddMod-r16 IE 2, …, N, respectively. ID 1 and configuration 1 are the CondReconfigId and the RRCReconfiguration message in the CondReconfigToAddMod IE 1, respectively. ID2, …, N and configurations 2, …, N are the CondReconfigId and the RRCReconfiguration message in the CondReconfigToAddMod IE 2, …, N, respectively. In some implementations, the first CondReconfigToAddModList-r16 IE includes the CondReconfigToAddMod-r16 IE 1, and the second CondReconfigToAddModList-r16 IE includes the CondReconfigToAddMod-r16 IE 2, …, N. In a further implementation, the first CondReconfigToAddModList-r16 IE includes the CondReconfigToAddMod-r16 IE 1, …, N.

[0086] In this example implementation, the base station 104 includes a conditional configuration (i.e., condExecutionCond-r16) in at least one IE in the CondReconfigToAddMod-r16IE. In some implementations, if the UE 102 supports a conditional procedure (e.g., conditional handover (CHO), conditional PSCell addition (CPA), or conditional PSCell change (CPC)), the UE 102 evaluates one or more conditions configured for the conditional procedure in the condExecutionCond-r16 field. If the UE 102 detects that at least one or all of one or more conditions in the condExecutionCond-r16 field in a particular CondReconfigToAddMod-r16 IE are satisfied, the UE 102 immediately applies the configuration in the RRCReconfiguration message in the CondReconfigToAddMod-r16 IE (e.g., as described in 3GPP specification 38.331). In some implementations, the base station 104 does not include a conditional configuration (i.e., condExecutionCond-r16) in any one or some IEs in the CondReconfigToAddMod-r16 IE. Accordingly, the UE 102 is not configured to perform any evaluation (i.e., detection or determination) of the conditions of a conditional procedure (e.g., conditional handover) for a CondReconfigToAddMod-r16 IE that does not include a conditional configuration (i.e., condExecutionCond-r16).

[0087] In some implementations, the release list is the CondReconfigToRemoveList-r16IE. In a further implementation, the base station 104 includes one or more CondReconfigID IEs in the CondReconfigToRemoveList-r16 IE to release one or more CondReconfigToAddMod-r16 IEs among CondReconfigToAddMod-r16 IEs 1, …, N. One or more CondReconfigToAddMod-r16 IEs are identified by one or more CondReconfigID IEs.

[0088] Example implementation 4

[0089] Example implementation 4 is similar to example implementation 3, except that in some implementations, a new indicator (e.g., the fastServingCellChange-r18 field) is optionally included in the CondReconfigToAddMod-r16 IE. In some implementations, the new indicator indicates that the CondReconfigToAddMod-r16 IE (i.e., the RRCReconfiguration message in the IE or condRRCReconfig-r16) is configured for fast serving cell change (i.e., see the description for event 312). If base station 104 does not include the new indicator in the CondReconfigToAddMod-r16 IE, the CondReconfigToAddMod-r16 IE is not configured for fast serving cell change.

[0090]

[0091] Example implementation 5

[0092] Some implementations in example implementations 3 and 4 may involve the UE 102 supporting conditional procedures (e.g., conditional handover (CHO), conditional PSCell addition (CPA), and / or conditional PSCell change (CPC)). If the UE 102 does not support conditional procedures, the base station 104 does not configure or enable fast serving cell change for the UE 102. Thus, example implementation 5 deviates from conditional procedures.

[0093]

[0094] In some implementations, the first addition or modification list is the first ReconfigToAddModList IE, and the second addition or modification list is the second ReconfigToAddModList IE. Element 1 is ReconfigToAddMod IE 1, and elements 2, …, N are ReconfigToAddMod IE 2, …, N respectively. ID 1 and Configuration 1 are the ConfigId and RRCReconfiguration IE in ReconfigToAddMod IE 1. ID 2, …, N and Configuration 2, …, N are the ConfigId and RRC ReconfigurationIE in ReconfigToAddMod IE 2, …, N respectively. In some implementations, the first ReconfigToAddModList IE includes ReconfigToAddMod IE 1, and the second ReconfigToAddModList IE includes ReconfigToAddMod IE 2, …, N. In further implementations, the first ReconfigToAddModList IE includes ReconfigToAddMod IE 1, …, N.

[0095] In some implementations, the release list is the ReconfigToReleaseList IE. In further implementations, the base station 104 includes one or more ConfigID IEs in the ReconfigToReleaseList IE to release one or more ReconfigToAddMod IEs in ReconfigToAddMod IE 1, …, N. One or more ReconfigToAddMod IEs are identified by one or more ConfigID IEs.

[0096] Example implementation 6

[0097]

[0098] Example implementation 6 is similar to example implementation 5, except that the ReconfigToAddMod IE does not include a ConfigId. In some implementations, IDs 1, …, N are implicitly indicated by the order of ReconfigToAddMod IEs 1, …, N in the first or second ReconfigToAddModList. For example, ReconfigToAddMod IE 1 is the first IE in the first ReconfigToAddModList IE, which implicitly indicates that ID 1 has a value of X. X can be zero or one. If the first ReconfigToAddModList IE includes ReconfigToAddMod IEs 1, …, N in order, then IDs 1, …, N have values X, X + 1, …, X+(N−1). In some implementations, if base station 104 sends a second ReconfigToAddModList IE to UE 102, then UE 102 and base station 104 replace the first ReconfigToAddModList IE with the second ReconfigToAddModList IE. If the second ReconfigToAddModList IE includes ReconfigToAddMod IEs 2, …, N in order, then IDs 2, …, N are values X, X + 1, …, X+N−2. If the second ReconfigToAddModList IE includes ReconfigToAddMod IEs 1, …, N in order, then IDs 1, …, N have values X, X + 1, …, X+N−1. In some alternative implementations, IDs 1, …, N are cell IDs 1, …, N.

[0099] In some implementations, base station 104 sends a ReconfigToAddModList IE that includes zero ReconfigToAddMod IEs to release all ReconfigToAddMod IEs 1, …, N.

[0100] In example implementations 5 and 6, "ReconfigToAddModList", "ReconfigToAddMod", "configId", "ConfigId", "cellGroupConfig", "ReconfigToReleaseList", and "maxNrofConfigCells" are exemplary and should not limit the scope and application of the present invention.

[0101] Example implementation 7

[0102] Example implementation 7 is a combination of example implementations 1 and 5, as shown below. Depending on the implementation, any one of configurations 1, …, N is a CellGroupConfig IE or an RRCReconfiguration message. The examples and implementations described for example implementations 1 and 5 can be applied to example implementation 7.

[0103]

[0104] maxNrofConfigCells::= 8 After receiving an RRC reconfiguration in event 306 or sending an RRC reconfiguration complete message in event 308, UE 102 sends 310 at least one measurement report to base station 104, similar to event 304. In some implementations, at least one measurement report for event 310 includes an L1 measurement report, an L3 measurement report, and / or a new type of measurement report, as described for event 304. In some implementations, UE 102 sends 310 at least one measurement report to base station 104 on the PUCCH and / or PUSCH, similar to event 304. In other implementations, UE 102 sends 310 at least one MAC CE including at least one measurement report to base station 104, similar to event 304. In some implementations, each measurement report in at least one measurement report for event 310 is not an RRC message.

[0105] In some implementations, the UE 102 sends at least one measurement report 310 to the base station 104 according to at least one measurement configuration. The base station 104 sends at least one measurement configuration to the UE 102 to configure the UE 102 to perform measurements and report the measurement results. For example, the base station 104 sends one or more RRC messages (e.g., RRCReconfiguration message) including at least one measurement configuration to the UE 102 after event 304 or event 306. Depending on the implementation, the one or more RRC messages include or do not include the RRC reconfiguration message for event 306. According to at least one measurement configuration, the UE 102 performs measurements on one or more reference signals. In some implementations, the one or more reference signals include one or more SSBs and / or one or more CSI-RSs. The UE 102 obtains at least one L1 measurement result and / or at least one L3 measurement result from the measurements, and includes at least one L1 measurement result and / or at least one L3 measurement result in at least one measurement report of event 310. The base station 104 sends one or more reference signals on cells 124A and 124B and in further implementations on cells 124C and / or other cells. In some implementations, the at least one measurement configuration includes an L3 measurement configuration (e.g., MeasConfig IE), an L1 measurement configuration (e.g., CSI-MeasConfig IE), and / or a new type of measurement configuration, as described for event 304.

[0106] In some implementations, the new type of measurement configuration described for events 304 and 310 is similar to the L3 measurement configuration. For example, the new type of measurement configuration includes a part of the configuration parameters defined in the MeasConfig IE. In other implementations, the new type of measurement configuration described for events 304 and 310 is similar to the L1 measurement configuration. For example, the new type of measurement configuration includes a part of the configuration parameters defined in the CSI-MeasConfig IE (e.g., CSI-ResourceConfig IE and / or CSI-ReportConfig IE).

[0107] After receiving at least one measurement report in event 310 (e.g., in response thereto), base station 104 sends 312 a first configuration activation command to UE 102 to activate configuration 1. For example, base station 104 sends the first configuration activation command on cell 124A. In another example, base station 104 sends the first configuration activation command on cell 124D. In some implementations, base station 104 includes ID 1 in the first configuration activation command. UE 102 determines and activates configuration 1 based on the first configuration activation command and ID 1. In other implementations, base station 104 includes cell index 1 (e.g., serving cell index) or cell ID 1 included in configuration 1 in the first configuration activation command. UE 102 determines and activates configuration 1 based on the first configuration activation command and cell index 1 or cell ID 1.

[0108] In other implementations, base station 104 includes a bitmap in the first configuration activation command to activate configuration 1, instead of ID 1, cell ID 1, or cell index 1. The number of bits in the bitmap is greater than or equal to "N". In some implementations, bits 1, ……, N correspond to configurations 1, ……, N respectively, and base station 104 sets the corresponding bit (e.g., bit 1) in the bitmap to a first value to indicate ID 1 or configuration 1. In a further implementation, bits 0, ……, N - 1 correspond to configurations 1, ……, N respectively, and base station 104 sets the corresponding bit (e.g., bit 0) in the bitmap to a first value to indicate ID 1 or configuration 1. Thus, in some such implementations, UE 102 determines a specific ID or a specific configuration based on bit 1 or bit 0 set to the first value in the bitmap. In such implementations, base station 104 sets the remaining bits in the bitmap to a second value to indicate that the reset of configurations 1, ……, N is not activated. In some implementations, 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. In some implementations, if base station 104 determines to activate another configuration (e.g., configuration K) in addition to configuration 1, then base station 104 sets the corresponding bit (e.g., bit K or bit K - 1) in the bitmap to the first value, where 1 <= K <= N.

[0109] In some implementations, at least one measurement report of event 310 (e.g., L1 measurement report and / or L3 measurement report) includes at least one measurement result for cell 124B. The base station 104 determines to activate configuration 1 because at least one measurement result indicates that the signal strength or quality of cell 124B is higher than a second predetermined threshold. The second predetermined threshold is different from the first predetermined threshold. In some implementations, the second predetermined threshold is greater than the first predetermined threshold. In such implementations, at least one measurement report of event 310 indicates that the signal strength or quality of cell 124B is suitable for communication with UE 102. In further implementations, the second predetermined threshold is equal to the first predetermined threshold. In such implementations, at least one measurement report of event 310 indicates that the signal strength or quality of cell 124B has been continuously higher than the second predetermined threshold or the first predetermined threshold. This also indicates that cell 124B is suitable for communication with UE 102. Therefore, the base station 104 determines to activate configuration 1 (i.e., fast serving cell change to cell 124B) in response to the signal strength or quality of cell 124B being higher than the second predetermined threshold.

[0110] In some implementations, the first configuration activation command is a MAC CE included in a MAC PDU that UE 102 receives from base station 104 in event 312. In some implementations, the MAC CE is a new MAC CE (e.g., as defined in 3GPP specification 38.321 v18.0.0 and / or later versions). In some implementations, the base station 104 includes a sub-header that identifies the MAC CE in the MAC PDU, and UE 102 identifies the MAC CE in the MAC PDU based on this sub-header. In further implementations, the sub-header includes a logical channel ID or an extended logical channel ID (e.g., as defined in the 3GPP specification) for identifying the MAC CE. For example, the logical channel ID or the extended logical channel ID is newly defined (e.g., in 3GPP specification 38.321 v18.0.0 and / or later versions). In other implementations, the first configuration activation command is a DCI that UE 102 receives on the PDCCH in event 312. The base station 104 generates a CRC for the DCI, scrambles the CRC with the first C-RNTI of UE 102, and transmits the DCI and the scrambled CRC on the PDCCH in event 312. In some implementations, the format of the DCI is an existing DCI format (e.g., as defined in the 3GPP specification (e.g., 38.212)). In further implementations, the format of the DCI is a new DCI format (e.g., as defined in the 3GPP specification (e.g., 38.212 v18.0.0 or later versions)).

[0111] In some implementations, the base station 104 does not perform security protection (e.g., integrity protection and / or encryption) on the first configuration activation command. This speeds up the processing of the first configuration activation command in the UE 102 because the UE 102 does not spend time performing security checks (e.g., decryption and / or integrity checks) on the first configuration activation command.

[0112] In some implementations, after receiving the first configuration activation command, the UE 102 sends a 313 confirmation to the base station 104 on cell 124A or cell 124D to indicate that the UE 102 has received the first configuration activation command. In some implementations, the confirmation is a HARQ ACK. In other implementations, the confirmation is a MAC CE. For example, the MAC CE is an existing MAC CE (e.g., defined in 3GPP specification 38.321 v17.1.0). In another example, the MAC CE is a new MAC CE (e.g., defined in 3GPP specification 38.321 v18.0.0 and / or later versions). In still other implementations, the confirmation is a PUCCH transmission.

[0113] In some implementations, the base station 104 sends a 306 RRC reconfiguration message to the UE 102 in response to an L3 measurement report for cell 124B received by the base station 104 in event 304. In some implementations, the base station 104 sends an RRC reconfiguration message including a MeasConfig IE to configure the UE 102 to send an L3 measurement report. In some implementations, the base station 104 sends a 312 first configuration activation command in response to an L1 measurement report for cell 124B received by the base station 104 in event 310. In further implementations, the base station 104 sends a second RRC reconfiguration message including a CSI-MeasConfig IE to configure the UE 102 to send an L1 measurement report. In some implementations, the first RRC reconfiguration message and the second RRC reconfiguration message are the same message (i.e., the same instance). In other implementations, the first RRC reconfiguration message and the second RRC reconfiguration message are different messages. In some implementations, the second RRC reconfiguration message is an RRC reconfiguration message for event 306. In other implementations, the second RRC reconfiguration message is different from the RRC reconfiguration message for event 306.

[0114] After receiving a first configuration activation command (e.g., in response thereto), the UE 102 identifies a specific configuration (e.g., Configuration 1) based on a specific ID (e.g., ID1) and immediately applies Configuration 1. In some implementations, the UE 102 performs a random access procedure with the base station 104 at 316 on cell 124B in response to applying Configuration 1. In some implementations, after receiving the 312 first configuration activation command or sending the 313 confirmation (e.g., in response thereto), the UE 102 disconnects 314 from cell 124A. In other words, after receiving the 312 first configuration activation command or sending the 313 confirmation (e.g., in response thereto), the UE 102 stops communicating on cell 124A. In such cases, the UE 102 performs the 316 random access procedure after disconnecting 314 from cell 124A. In some implementations, the UE 102 determines whether to perform a random access procedure based on Configuration 1. In some implementations, if Configuration 1 configures the UE 102 to perform a random access procedure, the UE 102 performs the random access procedure at event 316. For example, Configuration 1 includes a reconfiguration configuration with synchronization (e.g., ReconfigurationWithSync IE) to configure the UE 102 to perform a random access procedure. Otherwise, if Configuration 1 does not configure the UE 102 to perform a random access procedure or configures the UE 102 to skip the random access procedure, the UE 102 avoids performing a random access procedure with the base station 104 after receiving the first configuration activation command. In such cases, the UE 102 skips event 316. For example, if Configuration 1 excludes a reconfiguration configuration with synchronization, Configuration 1 configures the UE 102 not to perform a random access procedure. In some implementations, 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.

[0115] In the case where the UE 102 performs the random access procedure 316, after successfully completing the random access procedure, the UE 102 communicates with the base station 104 on the cell 124B according to Configuration 1 318. For example, the UE 102 conveys UL PDUs, DL PDUs, and / or physical layer signals (e.g., PUCCH transmissions and PDCCH transmissions) to the base station 104 in event 318. In such cases, when the UE 102 receives the contention resolution from the base station 104, the UE 102 successfully completes the random access procedure. In the case where the random access procedure is a four-step random access procedure, the UE 102 sends a message 3 including the UE identifier to the base station 104 via the cell 124B during the random access procedure. In the case where the random access procedure is a two-step random access procedure, the UE 102 sends a message A including the UE identifier to the base station 104 via the cell 124B during the random access procedure. In some implementations, if Configuration 1 includes a second C-RNTI, the UE identifier is the second C-RNTI of the UE 102. Otherwise, if Configuration 1 does not include a C-RNTI, the UE identifier is the first C-RNTI. In the case where the random access procedure is a contention-free random access procedure, the UE 102 sends a dedicated random access preamble to the base station 104 via the cell 124B. In such cases, Configuration 1 includes the dedicated random access preamble.

[0116] After receiving the UE identifier or the dedicated preamble from the UE 102 during the random access procedure, the base station 104 identifies or determines that the UE 102 is connected to the cell 124B.

[0117] In some implementations, the UE 102 sends an RRC message (e.g., an RRC reconfiguration complete message) to the base station 104 via the cell 124B to indicate that the UE 102 applies Configuration 1. In some implementations, the UE 102 includes the RRC message in message 3. In further implementations, the UE 102 includes the RRC message in message A. In still further implementations, the UE 102 sends the RRC message after completing the random access procedure. In other implementations, if the UE 102 maintains communication with the base station 104 on the cell 124A (i.e., the UE 102 is not disconnected from the cell 124A), the UE 102 sends the RRC message to the base station 104 via the cell 124A. In still other implementations, the UE 102 avoids sending the RRC message to the base station 104 in response to applying Configuration 1 or receiving the first configuration activation command.

[0118] In some cases where UE 102 skips some of the random access procedures, after receiving (e.g., in response to) the first configuration activation command, UE 102 communicates directly with base station 104 on cell 124B according to Configuration 1 for communication 318. For example, UE 102 conveys UL PDUs, DL PDUs, and / or physical layer signals (e.g., PUCCH transmissions and PDCCH transmissions) to base station 104 in event 318. In some such cases, after receiving (e.g., in response to) the first configuration activation command, UE 102 sends at least one PUCCH transmission to base station 104 on cell 124B according to Configuration 1. In some implementations, base station 104 sends at least one DCI to UE 102 on the PDCCH on cell 124B to command UE 102 to send at least one PUCCH or PUSCH transmission after sending the first configuration activation command. Base station 104 identifies or determines that UE 102 is connected to cell 124B after receiving the PUCCH or PUSCH transmission. In other implementations, UE 102 sends at least one PUCCH transmission regardless of whether it receives DCI on the PDCCH on cell 124B. Base station 104 identifies or determines that UE 102 is connected to cell 124B after receiving the PUCCH transmission. In some implementations, UE 102 sends an RRC message (e.g., an RRC reconfiguration complete message) to base station 104 via cell 124B in event 318 to indicate that UE 102 applies Configuration 1. Base station 104 identifies or determines that UE 102 is connected to cell 124B after receiving the RRC message. In other implementations, if UE 102 maintains communication with base station 104 on cell 124A (i.e., UE 102 is not disconnected from cell 124A), then UE 102 sends an RRC message to base station 104 via cell 124A. In still other implementations, UE 102 avoids sending an RRC message to base station 104 in response to applying Configuration 1 or receiving the first configuration activation command.

[0119] In some implementations, when it is determined that UE 102 is connected to cell 124B, sends the first configuration activation command 312, or receives 313 an acknowledgement, base station 104 stops communicating with UE 102 on cell 124A. In some implementations, when it is determined that UE 102 is connected to cell 124B, sends the first configuration activation command 312, or receives 313 an acknowledgement, base station 104 releases the resources of cell 124A that are configured for UE 102.

[0120] Events 304, 306, and 308 are collectively referred to as the serving cell configuration procedure 390 in Figure 3 Events 310, 312, 314, 316, and 318 are collectively referred to as the serving cell change procedure 392 in Figure 3 which.

[0121] In some implementations, the base station 104 generates Configuration 1 and / or Configuration 2, …, N as a complete configuration to replace the first configuration or a specific configuration in the first configuration. If Configuration 1 is a complete configuration, the UE 102 and the base station 104 replace the first configuration or the specific configuration in the first configuration with Configuration 1. Accordingly, the UE 102 and the base station 104 communicate with each other 318 according to Configuration 1 instead of the first configuration or the specific configuration. In some implementations, the RRC reconfiguration message for Event 306 includes an indication that Configuration 1 is a complete configuration. In other implementations, Configuration 1 includes an indication that Configuration 1 is a complete configuration. In still other implementations, the first container includes an indication that Configuration 1 is a complete configuration. In yet other implementations, Element 1 (e.g., ConfigToAddMod IE, CellGroupConfigToAddMod, MobilityToAddMod IE, MobilityConfigToAddMod IE, or CellGroupConfigToAddMod IE) includes an indication that Configuration 1 is a complete configuration. The UE 102 determines that Configuration 1 is a complete configuration based on the indication that Configuration 1 is a complete configuration. In some implementations, there is an indication that Configuration 1 is different from the fullConfig field (e.g., as defined in the current 3GPP specifications). In other implementations, Configuration 1 is an indication of the fullConfig field (e.g., as defined in the current 3GPP specifications) in the RRCReconfiguration message.

[0122] In other implementations, the base station 104 generates Configuration 1 and / or Configuration 2, …, N as an incremental configuration to augment at least a part of the first configuration. In other words, the base station 104 generates Configuration 1, …, N on top of the first configuration. For example, if Configuration 1 is an incremental configuration, the UE 102 and the base station 104 use Configuration 1 to augment at least a part of the first configuration. Accordingly, the UE 102 and the base station 104 communicate with each other 318 according to Configuration 1 and the un-augmented part of the first configuration. In some implementations, Configuration 1 includes an indication that Configuration 1 is an incremental configuration. In other implementations, the first container includes an indication that Configuration 1 is an incremental configuration. In still other implementations, Element 1 includes an indication that Configuration 1 is an incremental configuration. The UE 102 may determine that Configuration 1 is a complete configuration based on the indication that Configuration 1 is an incremental configuration. In some alternative implementations, Configuration 1, the first container, or Element 1 excludes an indication that Configuration 1 is a complete configuration to indicate that Configuration 1 is an incremental configuration. In further implementations, the UE 102 determines that Configuration 1 is an incremental configuration based on the determination that the indication is excluded in Configuration 1, the first container, or Element 1.

[0123] In some implementations, if Configuration 1 is a complete configuration, then after receiving the first configuration activation command 312, sending the confirmation 313, successfully executing the random access procedure 316, or receiving the first DCI on the PDCCH addressed to the UE identifier of UE 102 on cell 124B (e.g., in response to receiving the first configuration activation command, sending the confirmation, successfully executing the random access procedure, or receiving the first DCI on the PDCCH addressed to the UE identifier of the UE on this cell), UE 102 releases the first configuration or a specific configuration in the first configuration. In some implementations, if Configuration 1 is a complete configuration, then after sending the first configuration activation command 312, receiving the confirmation 313, successfully executing the random access procedure 316, or receiving a specific transmission from UE 102 on cell 124B (e.g., in response to sending the first configuration activation command, receiving the confirmation, successfully executing the random access procedure, or receiving the specific transmission from the UE on this cell), base station 104 releases the first configuration or a specific configuration in the first configuration. In some implementations, the specific transmission is a PUCCH transmission. In a further implementation, the transmission is a PUSCH transmission. In a further implementation, after sending the first configuration activation command, base station 104 generates a DCI and the CRC of the DCI, scrambles the CRC with the UE identifier of UE 102, and sends the DCI and the scrambled CRC on the PDCCH on cell 124B. When UE 102 receives the DCI and the scrambled CRC and verifies that the scrambled CRC is valid using the UE identifier, UE 102 sends a PUSCH transmission to base station 104 on cell 124B.

[0124] In some implementations, the first configuration or the specific configuration is the first CellGroupConfig IE (i.e., the first configuration includes the configuration parameters defined in the first CellGroupConfig IE), and Configuration 1 is the second CellGroupConfig IE.

[0125] In some implementations, the UE 102 uses a UE MAC entity (e.g., MAC 204B) to communicate with the base station 104 (e.g., events 302, 304, 306, 308, 310, and / or 312). In some implementations, the base station 104 configures whether the UE 102 resets the UE MAC entity after receiving the first configuration activation command at 312. In some implementations, the base station 104 includes a MAC reset indication in configuration 1 or element 1 to configure the UE 102 to reset the UE MAC entity, and excludes the MAC reset indication in configuration 1 or element 1 to configure the UE 102 not to reset the UE MAC entity. If configuration 1 or element 1 includes a MAC reset indication, the UE 102 resets the UE MAC entity in response to the MAC reset indication after receiving the first configuration activation command at 312.

[0126] Otherwise, if configuration 1 or element 1 does not include a MAC reset indication, the UE 102 avoids resetting the UE MAC entity after or when receiving the first configuration activation command. In some implementations, if configuration 1 or element 1 does not include a MAC reset indication and includes an indication that the configuration is fully configured, the UE 102 resets the UE MAC entity after or when receiving the first configuration activation command. Otherwise, if configuration 1 or element 1 does not include a MAC reset indication and an indication that the configuration is fully configured, the UE 102 avoids resetting the UE MAC entity after or when receiving the first configuration activation command.

[0127] In some implementations, the base station 104 uses a base station MAC entity (e.g., NRMAC 204B) to communicate with the UE 102 (e.g., events 302, 304, 306, 308, 310, and / or 312). If the base station 104 includes a MAC reset indication in configuration 1 or element 1, the base station 104 resets the base station MAC entity in response to the MAC reset indication after sending the first configuration activation command in event 312, receiving an acknowledgement in event 313, or determining that the UE 102 is connected to cell 124B in events 316 or 318.

[0128] Otherwise, if Configuration 1 or Element 1 does not include a MAC reset indication, then base station 104 avoids resetting the base station MAC entity after sending the first configuration activation command at 312 (e.g., in response thereto). Thus, after sending the first configuration activation command at event 312, receiving an acknowledgement at event 313, or determining at event 316 or 318 that UE 102 is connected to cell 124B, base station 104 continues to communicate with UE 102 using the reserved (i.e., non-reset) base station MAC entity. In the case where base station 104 is a split base station, base station 104 may determine whether to include a MAC reset indication in Configuration 1 or Element 1 depending on whether cells 124A and 124B belong to the same DU. If cells 124A and 124B belong to the same DU, then base station 104 determines not to include or does not include a MAC reset indication in Configuration 1 or Element 1. Otherwise, if cells 124A and 124B belong to different DUs, then base station 104 determines to include or includes a MAC reset indication in Configuration 1 or Element 1.

[0129] In some implementations, base station 104 includes a MAC reset indication in the MAC-CellGroupConfig IE in Configuration 1 (e.g., the CellGroupConfig IE). In other implementations, base station 104 includes a MAC reset indication in the CellGroupConfigIE and outside of the MAC-CellGroupConfig IE. In still other implementations, base station 104 includes a MAC reset indication in Element 1 and outside of Configuration 1.

[0130] In some implementations, if Configuration 1 or Element 1 does not include a MAC reset indication and includes an indication that Configuration 1 is fully configured, then after sending the first configuration activation command at event 312, receiving an acknowledgement at event 313, or determining at event 316 or 318 that UE 102 is connected to cell 124B, base station 104 resets the base station MAC entity. Alternatively, base station 104 releases the base station MAC entity and establishes a new base station MAC entity to communicate with UE 102 via cell 124B, rather than resetting the base station MAC entity. Otherwise, if Configuration 1 or Element 1 does not include a MAC reset indication and an indication that Configuration 1 is fully configured, then after sending the first configuration activation command at 312 (e.g., in response thereto), base station 104 avoids resetting the base station MAC entity.

[0131] In some alternative implementations, the base station 104 includes a MAC retention indication in a configuration or element (e.g., Configuration 1 or Element 1) to configure the UE 102 not to reset the UE MAC entity, and excludes the MAC retention indication in the configuration or element to configure the UE 102 to reset the UE MAC entity. If the configuration or element includes the MAC retention indication, then upon receiving a configuration activation command (e.g., a first configuration activation command), the UE 102 avoids resetting the UE MAC entity in response to the MAC retention indication. Otherwise, if the configuration or element does not include the MAC retention indication, then the UE 102 resets the UE MAC entity upon or after receiving the configuration activation command.

[0132] The base station 104 uses a base station MAC entity (e.g., NR MAC 204B) to communicate with the UE 102 (e.g., events 302, 304, 306, 308, 310, and / or 312). If the base station 104 includes the MAC retention indication in a configuration or element (e.g., Configuration 1 or Element 1), then after sending a configuration activation command (e.g., a first configuration activation command) to the UE 102, the base station 104 avoids resetting the base station MAC entity in response to the MAC retention indication. Thus, after sending the 312 first configuration activation command, receiving the 313 acknowledgement, or determining that the UE 102 is connected to cell 124B in events 316 or 318, the base station 104 continues to communicate with the UE 102 using the retained (i.e., non-reset) base station MAC entity.

[0133] In some implementations, the base station 104 includes the MAC retention indication in the MAC-CellGroupConfig IE in Configuration 1 (e.g., the CellGroupConfig IE). In other implementations, the base station 104 includes the MAC retention indication in and outside of the CellGroupConfig IE. In still other implementations, the base station 104 includes the MAC retention indication in Element 1 and outside of Configuration 1.

[0134] Otherwise, if Configuration 1 or Element 1 does not include the MAC retention indication, then the base station 104 resets the base station MAC entity after sending the 312 first configuration activation command (e.g., in response thereto). In some cases where the base station 104 is a split base station, the base station 104 determines whether to include the MAC reset indication in Configuration 1 or Element 1 depending on whether cells 124A and 124B belong to the same DU. If cells 124A and 124B belong to the same DU, then the base station 104 determines to include the MAC retention indication in Configuration 1 or Element 1. Otherwise, if cells 124A and 124B belong to different DUs, then the base station 104 determines not to include the MAC retention indication in Configuration 1 or Element 1.

[0135] In some implementations, the base station 104 may or may not include an indication that Configuration 1 is fully configured. If the base station 104 includes an indication that Configuration 1 is fully configured in Configuration 1 or Element 1, the base station 104 avoids including a MAC reservation indication in Configuration 1 or Element 1. Otherwise, in a further implementation, if the base station 104 does not include an indication that Configuration 1 is fully configured in Configuration 1 or Element 1, the base station 104 includes a MAC reservation indication in Configuration 1 or Element 1.

[0136] In a further alternative implementation, the base station 104 includes a MAC partial reset indication in a configuration or element (e.g., Configuration 1 or Element 1) to configure the UE 102 to partially reset the UE MAC entity, and excludes the MAC partial reset indication in the configuration or element to configure the UE 102 to fully reset the UE MAC entity. If the configuration or element includes a MAC partial reset indication, the UE 102 partially resets the UE MAC entity after receiving a configuration activation command (e.g., a first configuration activation command). Otherwise, if the configuration or element does not include a MAC partial reset indication, the UE 102 fully resets the UE MAC entity after receiving a configuration activation command (e.g., in response thereto). In some implementations, when the UE partially resets the UE MAC entity, the UE 102 retains (e.g., maintains or holds) the operating state of the UE MAC entity, or omits one or more actions that the UE 102 may perform when the UE fully resets the UE MAC entity.

[0137] If the base station 104 includes a MAC partial reset indication in a configuration or element (e.g., Configuration 1 or Element 1), after sending a configuration activation command (e.g., a first configuration activation command) to the UE 102, the base station 104 partially resets the base station MAC entity in response to the MAC partial reset indication.

[0138] In some implementations, the base station 104 includes a MAC partial reset indication in the MAC-CellGroupConfig IE in Configuration 1 (e.g., the CellGroupConfig IE). In other implementations, the base station 104 includes a MAC partial reset indication in the CellGroupConfig IE and outside the MAC-CellGroupConfig IE. In still other implementations, the base station 104 includes a MAC partial reset indication in Element 1 and outside Configuration 1.

[0139] Otherwise, if Configuration 1 or Element 1 does not include a MAC portion reset indication, the base station 104 fully resets the base station MAC entity after (e.g., in response to) transmitting the first configuration activation command 312. In some implementations, whether the base station 104 includes Configuration 1 is an indication of being fully configured. In some implementations, if the base station 104 includes an indication that Configuration 1 is fully configured in Configuration 1 or Element 1, the base station 104 avoids including a MAC portion reset indication in Configuration 1 or Element 1. Otherwise, in a further implementation, if the base station 104 does not include an indication that Configuration 1 is fully configured in Configuration 1 or Element 1, the base station 104 includes a MAC portion reset indication in Configuration 1 or Element 1. In some alternative implementations, in cases where the base station 104 includes an indication that Configuration 1 is fully configured in Configuration 1 or Element 1, the base station 104 includes a MAC portion reset indication.

[0140] In some implementations, the base station 104 does not include an indication related to resetting the UE MAC entity in a configuration or element (e.g., Configuration 1 or Element 1) or an RRC message (e.g., Event 306) including the configuration or element. In such cases, the UE 102 partially resets the UE MAC entity after (e.g., in response to) receiving the first configuration activation command. In such cases, after transmitting the first configuration activation command, receiving an acknowledgement 331, performing a random access procedure 336 with the UE 102, or determining that the UE 102 is connected to cell 124B, the base station 104 partially resets the base station MAC entity.

[0141] In some implementations, when the UE 102 determines to reset the UE MAC entity or resets the UE MAC entity as described above, the UE 102 resets the UE MAC entity before performing the random access procedure 316 or communicating with the base station 104 via the cell 124B 318. In some implementations, 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): (i) initialize Bj of the configured logical channel to zero; (ii) stop one or more timers; (iii) consider the timeAlignmentTimer expired if the UE 102 is configured to perform a random access procedure (e.g., event 316) in the configuration (e.g., configuration 1); (iv) set the new data indicator (NDI) for the UL HARQ process to the value 0; (v) set the NDI for the HARQ process ID to the value 0 for monitoring the PDCCH in the sidelink resource allocation mode 1; (vi) flush the Msg3 buffer; (vii) flush the MSGA buffer; (viii) cancel the triggered scheduling request process (if any); (ix) cancel the triggered buffer status report process (if any); (x) cancel the triggered power headroom report process (if any); (xi) cancel the triggered consistent LBT failure (if any); (xii) cancel the triggered BFR (if any); (xiii) cancel the triggered sidelink buffer status report process (if any); (xiv) cancel the triggered preemption buffer status report process (if any); (xv) cancel the triggered timing advance report process (if any); (xvi) cancel the triggered recommended bit rate query process (if any); (xvii) cancel the triggered configured uplink grant confirmation (if any); (xviii) cancel the triggered configured sidelink grant confirmation (if any); (xix) cancel the triggered desired guard symbol query (if any); (xx) cancel the triggered positioning measurement gap activation / deactivation request process (if any); (xxi) flush the soft buffer for the DL HARQ process; (xxii) for each DL HARQ process in the DL HARQ process, consider the next received transmission of the TB as the first transmission; (xxiii) release the temporary C-RNTI (if any); (xiv) reset one or more counters (e.g., BFI_COUNTER and / or LBT_COUNTER); (xxv) and so on.

[0142] In some implementations, when base station 104 resets the base station MAC entity, base station 104 performs at least one of the following actions for the base station MAC entity (i.e., base station MAC reset or full base station MAC reset): (i) stops one or more timers; (ii) if UE 102 is configured to perform a random access procedure (e.g., event 332) in a configuration (e.g., configuration 1), considers the timeAlignmentTimer started and / or maintained by base station 104 for UE 102 to be expired; (iii) sets the NDI for the DL HARQ process to the value 0; (iv) flushes the soft buffer for the UL HARQ process; (v) for each UL HARQ process in the UL HARQ process, considers the next received transmission of the TB to be the first transmission; (vi) resets one or more counters (e.g., BFI_COUNTER and / or LBT_COUNTER); (vii) and so on.

[0143] Depending on the implementation, UE 102 determines to partially or fully reset the UE MAC entity. In some implementations, when UE 102 resets the UE MAC entity as described above, UE 102 fully resets the UE MAC entity (i.e., full UE MAC reset). In a full UE MAC reset, UE 102 performs some or all of the actions described above. In other implementations, when UE 102 resets the UE MAC entity as described above, UE 102 partially resets the UE MAC entity (i.e., partial UE MAC reset). In a partial UE MAC reset, UE 102 performs a subset or part of some or all of the actions in a full UE MAC reset.

[0144] In some implementations, a partial UE MAC reset includes at least one of the following actions: (i) if UE 102 is configured to perform a random access procedure (e.g., event 332) in a configuration (e.g., configuration 1), considers the timeAlignmentTimer of UE 102 to be expired; (ii) flushes the Msg3 buffer; (iii) flushes the MSGA buffer; (iv) releases the temporary C-RNTI (if any); and / or (v) resets one or more counters (e.g., BFI_COUNTER and / or LBT_COUNTER).

[0145] In some implementations, partial UE MAC reset further includes at least one of the following actions: (i) Canceling a triggered scheduling request procedure (if any); (ii) Canceling a triggered buffer status report procedure (if any); (iii) Canceling a triggered power headroom report procedure (if any); (iv) Canceling a triggered consistent LBT failure (if any); (v) Canceling a triggered BFR (if any); (vi) Canceling a triggered sidelink buffer status report procedure (if any); (vii) Canceling a triggered pre-emption buffer status report procedure (if any); (viii) Canceling a triggered timing advance report procedure (if any); (ix) Canceling a triggered recommended bitrate query procedure (if any); (x) Canceling a triggered configured uplink grant confirmation (if any); (xi) Canceling a triggered configured sidelink grant confirmation (if any); (xii) Canceling a triggered desired guard symbol query (if any); and / or (xiii) Canceling a triggered positioning measurement gap activation / deactivation request procedure (if any).

[0146] In some implementations, partial UE MAC reset further includes at least one of the following actions: (i) Stopping a first portion of one or more timers and retaining the remaining portion of one or more timers; (ii) Setting a new data indicator (NDI) for a UL HARQ procedure to a value of 0; (iii) Setting the NDI for a HARQ process ID to a value of 0 for monitoring the PDCCH in sidelink resource allocation mode 1; (iv) Flushing soft buffers for DL HARQ procedures; and / or (v) For each DL HARQ procedure in DL HARQ procedures, treating the next received transmission of a TB as the first transmission.

[0147] Depending on the implementation, the base station 104 determines to partially or fully reset the base station MAC entity. In some implementations, when the base station 104 resets the base station MAC entity as described above, the base station 104 fully resets the base station MAC entity (i.e., full base station MAC reset). In a full base station MAC reset, the base station 104 performs some or all of the actions described above. In other implementations, when the base station 104 resets the base station MAC entity as described above, the base station 104 partially resets the base station MAC entity (i.e., partial base station MAC reset). In a partial base station MAC reset, the base station 104 performs a subset or portion of some or all of the actions in a full base station MAC reset.

[0148] In some implementations, partial base station MAC reset includes at least one of the following actions in the partial MAC reset: (i) if the UE 102 is configured to perform a random access procedure (e.g., event 332) in a configuration (e.g., configuration 1), consider the timeAlignmentTimer started and / or maintained by the base station 104 for the UE 102 as expired; and / or (ii) reset one or more counters (e.g., BFI_COUNTER and / or LBT_COUNTER).

[0149] In some implementations, when the partial base station MAC reset includes at least one of the following actions for the MAC entity (i.e., base station MAC reset): (i) stop the first part of one or more timers and retain the remaining part of one or more timers; (ii) set the NDI for the DL HARQ process to the value 0; (iii) flush the soft buffer for the UL HARQ process; (iv) for each UL HARQ process in the UL HARQ process, consider the next received transmission of the TB as the first transmission; and / or (v) reset one or more counters (e.g., BFI_COUNTER and / or LBT_COUNTER).

[0150] In some implementations, Configuration 1 includes or does not include one or more RLC reestablishment indications (e.g., the reestablishRLC field) that configure the UE 102 to reestablish one or more RLC entities (e.g., RLC 206B) that the UE 102 uses to communicate with the base station 104 (e.g., events 302, 304, 306, 308, 310, and / or 312). If Configuration 1 includes an RLC reestablishment indication that configures the UE 102 to reestablish an RLC entity (e.g., RLC 206B) that the UE 102 uses to communicate RLC PDUs with the base station 104 (e.g., events 302, 304, 306, 308, 310, and / or 312), the UE 102 reestablishes the RLC entity in response to the RLC reestablishment indication. In some implementations, the UE 102 reestablishes the RLC entity before performing the random access procedure 316 or communicating with the base station 104 via cell 124B 318. In other implementations, the UE 102 reestablishes the RLC entity during or after performing the random access procedure 316. In some implementations, when the UE 102 reestablishes the RLC entity, the UE 102 performs at least one of the following actions for the RLC entity: (i) discarding RLC SDUs, RLC SDU segments, and RLC PDUs (if any); (ii) stopping and resetting timers (if running); (iii) resetting state variables to initial values; (iv) and so on. In some implementations, the state variables and timers are currently defined (e.g., in 3GPP specification 38.322).

[0151] Otherwise, if Configuration 1 does not include an RLC reestablishment indication for the RLC entity, the UE 102 avoids reestablishing the RLC entity when or upon receiving the first configuration activation command. In other words, the UE 102 avoids performing actions for reestablishing the RLC entity of the UE 102 when or upon receiving the first configuration activation command. In some implementations, if Configuration 1 or Element 1 does not include an RLC reestablishment indication and includes an indication that Configuration 1 is fully configured, the UE 102 reestablishes the RLC entity of the UE 102 after or when receiving the first configuration activation command. Otherwise, if Configuration 1 or Element 1 does not include an RLC reestablishment indication and an indication that Configuration 1 is fully configured, the UE 102 avoids reestablishing the RLC entity after or when receiving the first configuration activation command.

[0152] Similarly, the base station 104 reconstructs the RLC entity (e.g., NR RLC 206B) that the base station 104 uses to communicate with the RLC entity of the UE 102 (e.g., events 302, 304, 306, 308, 310, and / or 312) in response to an RLC reconstruction indication. In some implementations, the base station 104 reconstructs the RLC entity after transmitting the first configuration activation command, receiving an acknowledgement for the first configuration activation command from the UE 102, or determining that the UE 102 is connected to cell 124B. In some implementations, the acknowledgement is a HARQ ACK. In other implementations, the acknowledgement is a MAC CE. In still other implementations, the acknowledgement is a PUCCH transmission. In some implementations, when the base station 104 reconstructs the RLC entity, the base station 104 performs at least one of the following actions for the RLC entity: (i) discarding RLC SDUs, RLC SDU segments, and RLC PDUs (if any); (ii) stopping and resetting the timer (if running); (iii) resetting the state variable to an initial value; (iv) etc. In some implementations, the state variable and the timer are currently defined (e.g., in 3GPP specification 38.322).

[0153] In some implementations, the above description for Configuration 1 also applies to Configurations 2, …, N.

[0154] Next, referring to Figure 4A, in scenario 400A, base station 106 operates as an MN, and base station 104 operates as an SN. Initially, UE 102 under DC communicates with MN 106 and SN 104. In event 402, UE 102 communicates with SN 104 on cell 124A according to a first configuration, similar to event 302. In some implementations, UE 102 under DC conveys 402 UL PDUs and / or DL PDUs to MN 106 and / or SN 104 via a radio bearer, which may include an SRB and / or a DRB. In further implementations, MN 106 and / or SN 104 configure the radio bearer for UE 102. UE 102 under DC conveys 402 UL PDUs and / or DL PDUs to SN 104 on the SCG configured by SN 104 for communicating with UE 102. UE 102 under DC conveys UL PDUs and / or DL PDUs to MN 106 on the MCG according to the MN configuration (i.e., MCG configuration). In some implementations, the first configuration is an SN configuration (i.e., SCG configuration). In the MN configuration, MN 106 configures the MCG, which includes at least one serving cell operated by MN 106 (e.g., cell 126 and / or other cells). In the first configuration, SN106A configures the SCG, which includes at least one serving cell operated by SN 104 (e.g., cell 124A and / or other cells). In some implementations, the MN configuration includes multiple configuration parameters, and UE 102 receives the configuration parameters in one or more RRC messages from MN 106. In other implementations, the first configuration includes multiple configuration parameters, and UE 102 (e.g., via MN 106) receives the configuration parameters in one or more RRC messages from SN 104 or on an SRB (e.g., SRB3) configured by MN 106 or SN 104 for exchanging RRC messages between UE 102 and SN 104.

[0155] In some implementations, when the UE 102 communicates with the MN 106 and the SN 104 under DC, the MN 106 performs a fast serving cell change procedure with the UE 102. In a further implementation, when communicating with the MN 106 and the SN 104 under DC, the UE 102 sends at least one measurement report to the MN 106 via cell 126, similar to event 304. The MN 106 then sends at least one measurement report to the SN 104. In some implementations, the MN 106 generates at least one interface message including at least one measurement report and sends at least one interface message to the SN 104 in event 403. In some implementations, at least one interface message includes an RRC transfer message and / or an SN modification request message. Alternatively, the UE 102 sends at least one measurement report to the SN 104 via cell 124A, similar to event 304.

[0156] After receiving at least one measurement report (e.g., in response thereto) or when the base station 104 communicates with the UE 102, the base station 104 determines to prepare cell 124B, as described for Figure 3 Events 406, 408, 410, 412, 413, 414, 416, and 418 are respectively similar to events 306, 308, 310, 312, 313, 314, 316, and 318. After receiving the first configuration activation command, sending an acknowledgement, or determining that the UE 102 is connected to cell 124B, the UE 102 operating with the MN 106 and the SN 104 under DC communicates with the SN 104 on cell 124B according to Configuration 1 in 418, similar to event 318.

[0157] Events 401, 403, 404, 406, 408 are collectively referred to as the serving cell configuration procedure 491A in Figure 4A Events 410, 412, 414, 416, and 418 are collectively referred to as the serving cell change procedure 493 in Figure 4A

[0158] Next, refer to Figure 4B ​, Scenario 400B is generally similar to Scenario 400A, except that SN 104 sends 405, 407 RRC reconfiguration messages to UE 102 via MN106 and receives 409, 411 RRC reconfiguration complete messages from UE 102 via MN 106. In some implementations, SN 104 generates a first interface message (e.g., a message requiring SN modification, a message requiring SN modification, or an RRC transfer message) including the RRC reconfiguration message and sends the first interface message to MN 106 in event 405. In some implementations, MN 106 generates a second interface message (e.g., an SN reconfiguration complete message or an RRC transfer message) including the RRC reconfiguration complete message and sends the second interface message to SN 104 in event 411.

[0159] Events 401, 403, 404, 405, 407, 409, and 411 are collectively referred to as the serving cell configuration procedure 491B in Figure 4B the following.

[0160] Next, several example methods that can be implemented in one or more RAN nodes such as a base station, DU, or CU or in the RAN to support configuring a configuration and later activating the configuration are discussed with reference to FIGS. 5 to 10. For Figures 3 to 4B the examples and implementations described are applicable to FIGS. 5 to 10.

[0161] Figure 5A Method 500A is shown, which can be implemented by a first base station (e.g., base station 104 or 106) to manage a configuration for a UE (e.g., UE 102) for later activation.

[0162] Method 500A begins at block 502, where a first base station communicates with a UE using a first plurality of configuration parameters (e.g., events 302, 390, 402, 490). At block 504, the first base station sends at least one configuration for later activation to the UE (e.g., events 306, 390, 406, 405, 407, 490). At block 506, before sending an activation command to activate any of the at least one configuration, the first base station determines to hand over the UE to a second base station. At block 508A, the first base station generates a handover request message in response to the determination, the handover request message including the first plurality of configurations and excluding the at least one configuration. At block 510, the first base station sends the handover request message to the second base station. At block 512, the first base station receives a handover request confirmation message from the second base station, the handover request confirmation message including an RRC message for the handover. At block 514, the first base station sends the RRC message to the UE. At block 516, the first base station releases the at least one configuration. In some implementations, the RRC message is an RRCReconfiguration message. In some implementations, the RRC message includes configuration parameters for the UE to communicate with the second base station.

[0163] Figure 5B is a flowchart of an example method 500B that is similar to method 500A, except that method 500B includes blocks 508B, 511, and 513 instead of blocks 508A, 510, and 512. At block 508B, in response to determining to hand over the UE to a second base station, the first base station generates a handover requirement message, the handover requirement message including the first plurality of configurations and excluding the at least one configuration. At block 511, the first base station sends the handover requirement message to the core network. At block 513, the first base station receives a handover command message from the core network, the handover command message including an RRC message for the handover.

[0164] Figure 5C is a flowchart of an example method 500C that is similar to method 500A, except that method 500C includes blocks 507, 516, and 508C instead of block 508A. At block 507, the first base station sends an RRC message to the UE to release at least one configuration for later activation in response to determining to hand over the UE to a second base station. At block 516, the first base station releases the at least one configuration. At block 508C, the first base station generates a handover request message including the first plurality of configurations.

[0165] Figure 5DIt is a flowchart of an exemplary method 500D similar to method 500C, except that method 500D includes blocks 508D, 511, and 513 instead of blocks 508C, 510, and 512. At block 508D, the first base station generates a handover requirement message in response to determining to hand over the UE to the second base station, and the handover requirement message includes a first plurality of configurations. At block 511, the first base station sends the handover requirement message to the core network. At block 513, the first base station receives a handover command message from the core network, and the handover command message includes an RRC message for the handover.

[0166] Figure 6A Illustrated is a method 600A that may be implemented by a first base station (e.g., base station 104 or 106) for managing configurations for a UE (e.g., UE 102) for later activation.

[0167] Method 600A begins at block 602, where the first base station receives a handover request message from the second base station, and the handover request message includes a first plurality of configurations and a configuration for later activation. At block 604, the first base station ignores or discards the configuration for later activation. In other words, the first base station avoids using the configuration for later activation. At block 606, the first base station generates a second plurality of configuration parameters for the handover based on the first plurality of configuration parameters. At block 608, the first base station includes the second plurality of configuration parameters in an RRC message. At block 610, the first base station includes a release indication for configuring the UE to release the configuration for later activation. At block 612, the first base station sends a handover request confirmation message including the RRC message to the second base station. The flow continues from block 610 and from block 608 to block 612.

[0168] Figure 6B It is a flowchart of an exemplary method 600B similar to method 600A, except that method 600B includes blocks 603 and 613 instead of blocks 602 and 612. At block 603, the first base station receives a handover request message from the core network, and the handover request message includes a first plurality of configurations and a configuration for later activation. At block 613, the first base station sends a handover request confirmation message including the RRC message to the core network. The flow continues from block 610 and from block 608 to block 613.

[0169] Figure 7 Illustrated is a method 700 that may be implemented by a first base station (e.g., base station 104 or 106) for managing configurations for a UE (e.g., UE 102) for later activation.

[0170] Method 700 begins at block 702, where a first base station receives a container from a second base station, the container including a first plurality of configurations for a UE. In some implementations, the container is an IE (e.g., HandoverPreparationInformationIE). At block 704, the first base station generates a second plurality of configuration parameters for a handover based on the first plurality of configuration parameters. At block 706, the first base station includes the second plurality of configuration parameters in an RRC message. At block 708, the first base station determines whether the container includes a configuration for later activation. If the first base station determines at block 708 that the container includes a configuration for later activation, the process proceeds to block 710. At block 710, the first base station releases the configuration for later activation. At block 712, the first base station includes a release indication for releasing the configuration for later activation in the RRC message. At block 714, the first base station sends the RRC message to the second base station. Otherwise, if the first base station determines at block 708 that the container does not include a configuration for later activation, the process proceeds to block 714. The process proceeds from block 712 and from block 708 to block 714.

[0171] Figure 8A Method 800A is shown, which may be implemented by a base station (e.g., base station 104 or 106) to manage configurations for later activation with a UE (e.g., UE 102).

[0172] Method 800A begins at block 802, where the base station communicates with the UE via a first cell using a first plurality of configurations (e.g., events 302, 390, 402, 490). At block 804, the first base station sends a configuration for later activation to the UE (e.g., 306, 390, 406, 405, 407, 490). At block 806, the base station sends an RRC message to the UE to hand over the UE to a second cell. At block 808, the base station releases the configuration for later activation in response to handing over the UE to the second cell.

[0173] In some implementations, the base station retains a first portion of the first plurality of configurations and releases the remainder of the first plurality of configurations in response to handing over the UE to the second cell. In other implementations, the base station releases the first plurality of configurations in response to handing over the UE to the second cell. In still other implementations, the base station retains the first plurality of configurations in response to handing over the UE to the second cell.

[0174] In some implementations, the base station includes a release indication in the RRC message to configure the UE to release the configuration for later activation. In other implementations, the base station does not include a release indication in the RRC message.

[0175] Figure 8BFIG. 800B is a flow chart of an example method 800B that is similar to method 800A, except that method 800B includes block 809 instead of block 808. At block 809, the base station preserves the configuration for later activation in response to switching the UE to a second cell.

[0176] In some implementations, the base station avoids including a release indication in the RRC message that is used to configure the UE to release the configuration for later activation.

[0177] Figure 9 FIG. 900 is shown, which can be implemented by a base station (e.g., base station 104 or 106) to manage the configuration for later activation with a UE (e.g., UE 102).

[0178] Method 900 begins at block 902, where the base station communicates with the UE via a first cell using a first plurality of configurations (e.g., events 302, 390, 402, 490). At block 904, the base station sends the configuration for later activation to the UE (e.g., 306, 390, 406, 405, 407, 490). At block 906, the base station determines to switch the UE to a second cell. At block 908, the base station determines whether to release the configuration for later activation. If the base station determines to release the configuration for later activation, the flow proceeds to block 910. At block 910, the base station releases the configuration for later activation. At block 912, the base station includes a release indication for releasing the configuration for later activation in the RRC message. At block 914, the base station sends a container including the RRC message to a second base station. Otherwise, if the base station determines at block 908 not to release the configuration for later activation, the flow proceeds to block 914. The flow proceeds from block 912 and from block 908 to block 914.

[0179] In some implementations, the release indication is a release list IE that includes an ID identifying the configuration for later activation. In some implementations, the RRC message is an RRCReconfiguration message.

[0180] Figure 10A FIG. 1000A is shown, which can be implemented by a UE (e.g., UE 102) to manage the configuration for later activation with a RAN (e.g., DU 174, CU 172, base station 104 / 106, or RAN 105).

[0181] Method 1000A begins at block 1002, where the UE communicates with the RAN using a first plurality of configurations (e.g., events 302, 390, 402, 490). At block 1004, the UE receives from the RAN a configuration for later activation (e.g., 306, 390, 406, 405, 407, 490). At block 1006, the UE receives from the RAN an RRC message that switches the UE to a second cell. At block 1008, the UE performs a handover to the second cell in response to the RRC message. At block 1010, the UE releases the configuration for later activation in response to the RRC message. At block 1012, the UE releases a portion of the first plurality of configuration parameters in response to the RRC message.

[0182] In some implementations, the UE sends an RRC response message on the second cell in response to the RRC message. In some implementations, the RRC message and the RRC response message are an RRCReconfiguration message and an RRCReconfigurationComplete message, respectively.

[0183] In some implementations, the RRC message includes a second plurality of configuration parameters. After switching to the second cell, the UE communicates on the second cell according to the second plurality of configuration parameters.

[0184] Figure 10B is a flow diagram of an example method 1000B that is similar to method 1000A, except that method 1000B includes block 1011 instead of block 1010. At block 1011, the UE retains the configuration for later activation in response to the RRC message.

[0185] Figure 10C is a flow diagram of an example method 1000C that is similar to method 1000A, except that method 1000C includes blocks 1007 and 1011 instead of block 1008. At block 1007, the UE determines whether the RRC message includes a release indication to release the configuration for later activation. If the UE determines at block 1007 that the RRC message includes a release indication to release the configuration for later activation, the flow proceeds to block 1010. Otherwise, if the UE determines at block 1007 that the RRC message does not include a release indication to release the configuration for later activation, the flow proceeds to block 1011. At block 1011, the UE retains the configuration for later activation in response to the RRC message. The flow proceeds from block 1010 and from block 1011 to block 1012.

[0186] Figure 11 illustrates a method 1100 that may be implemented by a base station (e.g., base station 104 or 106) to manage configurations for later activation with a UE (e.g., UE 102).

[0187] Method 1100 begins at block 1102, where the base station communicates with the UE via a first cell and using a first plurality of configurations (e.g., events 302, 390, 402, 490). At block 1104, the base station receives measurement results for a second cell from the UE (e.g., events 304, 390, 404, 490). At block 1106, the base station determines whether the second cell is operated by the base station. If the base station determines that the second cell is operated by the base station, the process proceeds to block 1108. At block 1108, the base station sends a configuration for later activation to the UE (e.g., 306, 390, 406, 405, 407, 490). Otherwise, if the base station determines that the second cell is not operated by the base station, the process proceeds to block 1110. At block 1110, the base station refrains from sending a configuration for later activation to the UE. In some implementations, at block 1012, the base station sends an RRC message to the UE to handover the UE to the second cell.

[0188] The following description may apply to the above description.

[0189] In general, the description for one of the above figures may apply to another of the above figures. If there is no conflict, the above examples, implementations, and methods may be combined. The events or blocks described above may be optional or omitted. For example, events or blocks with dashed lines in the figures may be optional. In some implementations, "message" is used and "message" may be replaced with "information element (IE)", and vice versa. In some implementations, "IE" is used and "IE" may be replaced with "field", and vice versa. In some implementations, "configuration" may be replaced with "configurations" or "configuration parameters", and vice versa. In some implementations, "configuration activation command" may be replaced with "serving cell change command", "layer 1 / layer 2 handover command", "lower layer handover command", or "lower layer serving cell change command". "Fast serving cell configuration process" may be replaced with "fast serving cell change process".

[0190] A user device (e.g., UE 102) that can implement the technology of the present disclosure can be any suitable device capable of wireless communication, such as a smart phone, a tablet computer, a laptop computer, a mobile game console, a point-of-sale (POS) terminal, a health monitoring device, a drone, a camera, a media streaming dongle or another personal media device, a wearable device such as a smart watch, a wireless hotspot, a femtocell or a broadband router. Further, in some cases, the user device can be embedded in an electronic system such as a host unit of a vehicle or an advanced driver assistance system (ADAS). Still further, the user device can operate as an Internet of Things (IoT) device or a mobile Internet device (MID). Depending on the type, the user device can include one or more general-purpose processors, computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0191] Certain embodiments are described in the present disclosure as including logic or a plurality of components or modules. A module can be a software module (e.g., code or machine-readable instructions stored on a non-transitory machine-readable medium) or a hardware module. A hardware module is a tangible unit capable of performing certain operations and can be configured or arranged in a certain manner. A hardware module can include dedicated circuitry or logic that is permanently configured to perform certain operations (e.g., as a dedicated processor, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), a digital signal processor (DSP), etc.). A hardware module can also include programmable logic or circuitry that is temporarily configured by software to perform certain operations (e.g., as included 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) can be driven by cost and time considerations.

[0192] When implemented in software, these technologies can be provided as part of an operating system, a library used by multiple applications, a specific software application, etc. The software can be executed by one or more general-purpose processors or one or more dedicated processors.

[0193] After reading the present disclosure, those skilled in the art will understand additional and alternative structural and functional designs for handling mobility between base stations through the principles disclosed herein. Thus, while specific embodiments and applications have been shown and described, it should be understood that the disclosed embodiments are not limited to the exact construction and components disclosed herein. Various modifications, changes, and variations that will be apparent to those of ordinary skill in the art can be made to the arrangement, operation, and details of the methods and devices disclosed herein without departing from the spirit and scope defined in the appended claims.

Claims

1. A method in a first node of a radio access network (RAN), the method comprising: Communicating with a user equipment (UE) in a first cell according to a first configuration; Sending a message to the UE, the message including a second configuration for accessing a second cell after an activation command; After the sending and while the UE is waiting for the activation command, sending a handover message to a second node of the RAN or a core network (CN); And Releasing the second configuration.

2. The method according to claim 1, wherein: The handover message includes the first configuration and excludes the second configuration.

3. The method according to claim 1 or 2, further comprising: In response to the handover message, receiving a second handover message including a radio resource control (RRC) message; And Sending the RRC message to the UE.

4. The method according to claim 3, wherein the second handover message includes a handover request confirmation message.

5. The method according to claim 3, wherein the second handover message includes a handover command message.

6. The method according to claim 1 or 2, further comprising: Sending an RRC message to the UE, the RRC message including an indication for releasing the second configuration.

7. The method according to claim 6, wherein the sending of the RRC message occurs before the sending of the handover message.

8. The method according to claim 6, wherein the sending of the RRC message occurs after the sending of the handover message.

9. The method according to any one of claims 1 to 3, wherein: The handover message includes a handover request message, and The sending of the handover message includes sending the handover request message to the second node of the RAN implemented in another base station.

10. The method according to any one of claims 1 to 3, wherein: The handover message includes a handover requirement message, and The sending of the handover message includes sending the handover requirement message to the CN.

11. The method according to any one of the preceding claims, further comprising: Including an identifier assigned to the second configuration in the message; Wherein The UE waits for the activation command including the identifier.

12. A method implemented in a first node of a radio access network (RAN), the method comprising: Receiving a handover message from a second node of the RAN or a core network (CN), the handover message including (i) one or more first parameters for immediate application at a user equipment (UE), and (ii) one or more second parameters for application at the UE after an activation command from the RAN; Discarding the one or more second parameters; And Sending a message including a configuration based on the one or more first parameters to the second node of the RAN or to the CN.

13. The method according to claim 10, further comprising: Including an indication for releasing the one or more second parameters at the UE in the handover message.

14. The method according to claim 12 or 13, further comprising: receiving, in the handover message, an identifier assigned to the one or more second parameters; wherein the UE waits for the activation command including the identifier.

15. A node in a radio access network RAN, comprising processing hardware and configured to implement the method according to any one of the preceding claims.

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