Method and apparatus for supporting coexistence of different types of mobility

Abstract

The embodiment of the invention relates to a method and equipment for supporting coexistence of different types of mobility. In accordance with some embodiments of the present disclosure, a user equipment (UE) may include: a transceiver; and a processor coupled to the transceiver and configured to: receive, via the transceiver, first configuration information related to a lower layer triggered mobility (LTM) operation or a secondary cell group (SCG) selective activation (SCGSA) operation; receiving, via the transceiver, second configuration information related to layer 3 (L3) cell handover; determining whether to apply the second configuration information to perform the L3 cell handover; and in response to determining to apply the second configuration information to perform the L3 cell handover, applying the second configuration information based on the first configuration information to perform the L3 cell handover.

Description

Technical Field

[0001] Embodiments of the present application relate generally to wireless communication techniques, and in particular, to methods and apparatus for supporting coexistence of different types of mobility. Background Art

[0002] Wireless communication systems are widely deployed to provide various telecommunication services, such as telephony, video, data, messaging, broadcasts, and the like. Wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources, such as time, frequency, and power. Examples of wireless communication systems include fourth-generation (4G) systems, such as Long Term Evolution (LTE), LTE-Advanced (LTE-A), or LTE-A Pro systems, and fifth-generation (5G) systems, which may also be referred to as New Radio (NR) systems.

[0003] Different types of mobility can be supported in wireless communication systems. However, detailed procedures and signaling enhancements between network nodes supporting the coexistence of different types of mobility have not been discussed. Summary of the Invention

[0004] Embodiments of the present application provide technical solutions at least for supporting the coexistence of different types of mobility.

[0005] According to some embodiments of the present application, a user equipment (UE) may include: a transceiver; and a processor, which is coupled to the transceiver and configured to: receive first configuration information related to lower layer triggered mobility (LTM) operation or secondary cell group (SCG) selective activation (SCGSA) operation via the transceiver; receive second configuration information related to layer 3 (L3) cell switching via the transceiver; determine whether to apply the second configuration information to perform the L3 cell switching; and in response to determining to apply the second configuration information to perform the L3 cell switching, apply the second configuration information based on the first configuration information to perform the L3 cell switching.

[0006] In some embodiments of the present application, the first configuration information is associated with a reference configuration related to the LTM operation or the SCGSA operation, the second configuration information includes a differential configuration on top of the reference configuration, and in order to apply the second configuration information based on the first configuration information to perform the L3 cell handover, the processor is configured to: apply the differential configuration based on the reference configuration to perform the L3 cell handover, regardless of which cell the UE is currently connected to.

[0007] In some embodiments of the present application, the first configuration information includes a set of configurations related to the LTM operation or the SCGSA operation, each of the set of configurations is associated with a corresponding candidate cell within a set of candidate cells including a current cell to which the UE is connected, the second configuration information includes a differential configuration on top of the configuration associated with the current cell within the set of configurations, and in order to apply the second configuration information based on the first configuration information to perform the L3 cell switching, the processor is configured to: apply the differential configuration based on the configuration associated with the current cell to perform the L3 cell switching.

[0008] In some embodiments of the present application, the first configuration information is associated with a reference configuration and includes a set of configurations related to the LTM operation or the SCGSA operation, each of the set of configurations is associated with a corresponding candidate cell within a set of candidate cells including the target cell of the L3 cell handover, each of the set of configurations is a corresponding first differential configuration associated with the corresponding candidate cell or the reference configuration, the second configuration information includes the reference configuration or at least one of the first differential configurations associated with the target cell within the set of configurations, and in order to apply the second configuration information based on the first configuration information to perform the L3 cell handover, the processor is configured to: apply the second differential configuration based on the reference configuration or at least one of the first differential configurations associated with the target cell to perform the L3 cell handover to the target cell.

[0009] In some embodiments of the present application, the first configuration information is associated with a reference configuration and includes a set of configurations related to the LTM operation, each of the set of configurations is associated with a corresponding candidate cell within a set of candidate cells, each of the set of configurations is a corresponding first delta configuration associated with the corresponding candidate cell or the reference configuration, the second configuration information is a message instructing the UE to perform the L3 cell handover to a candidate cell within the set of candidate cells, and in order to apply the second configuration information based on the first configuration information to perform the L3 cell handover, the processor is configured to: apply the reference configuration or at least one of the first delta configurations associated with the candidate cell within the set of configurations to perform the L3 cell handover to the candidate cell.

[0010] In some embodiments of the present application, the second configuration information includes an identification (ID) of the candidate cell.

[0011] In some embodiments of the present application, the reference configuration is a configuration associated with the cell to which the UE is connected when it receives the first configuration information, or a configuration that is different from the configuration of all candidate cells related to the LTM operation or the SCGSA operation, or a configuration associated with the candidate cells related to the LTM operation or the SCGSA operation.

[0012] In some embodiments of the present application, the processor is further configured to determine not to apply the second configuration information to perform the L3 cell switching in at least one of the following situations: the UE has switched to a cell according to an LTM command or according to a conditional configuration related to the SCGSA operation within a certain time period, and the cell is different from the target cell of the L3 cell switching indicated by the second configuration information; or the source cell of the L3 cell switching indicated by the second configuration information is different from the cell to which the UE is currently connected.

[0013] In some embodiments of the present application, the processor is further configured to transmit, via the transceiver, to a network node an indication indicating that the second configuration information is not to be applied.

[0014] In some embodiments of the present application, the indication includes a cause value indicating an erroneous source cell.

[0015] According to some embodiments of the present application, a first network node may include: a transceiver; and a processor coupled to the transceiver and configured to: determine to trigger L3 cell handover of a UE; and transmit configuration information related to the L3 cell handover to a second network node or the UE via the transceiver.

[0016] In some embodiments of the present application, the processor is further configured to: transmit a first message to a third network node via the transceiver, wherein the first message includes a reference configuration related to the LTM operation or the SCGSA operation; and receive a second message via the transceiver in response to the first message from the third network node, wherein the second message includes a delta configuration on top of the reference configuration; and the configuration information includes the delta configuration.

[0017] In some embodiments of the present application, the processor is further configured to: transmit one or more first messages to a third network node via the transceiver, wherein the one or more first messages include a set of configurations related to the LTM operation or the SCGSA operation, and each of the set of configurations is associated with a corresponding candidate cell within a set of candidate cells; and receive one or more second messages via the transceiver in response to the one or more first messages from the third network node, wherein the one or more second messages include a set of delta configurations, and each delta configuration within the set of delta configurations is associated with a corresponding candidate cell within the set of candidate cells and is generated based on the configuration associated with the corresponding candidate cell within the set of configurations.

[0018] In some embodiments of the present application, the processor is further configured to: determine a current cell to which the UE is connected, wherein the current cell is within the set of candidate cells and the configuration information includes a differential configuration associated with the current cell within the set of differential configurations.

[0019] In some embodiments of the present application, the processor is further configured to: determine a target cell for the L3 cell switching, wherein the target cell is within a set of candidate cells related to the LTM operation or the SCGSA operation, wherein each candidate cell within the set of candidate cells is associated with a corresponding first differential configuration or is a reference configuration related to the LTM operation or the SCGSA operation, and wherein the configuration information includes a second differential configuration on top of at least one of the reference configuration or the first differential configuration associated with the target cell.

[0020] In some embodiments of the present application, the processor is further configured to: determine a target cell for the L3 cell handover, wherein the target cell is within a set of candidate cells related to the LTM operation, and wherein the configuration information is a message requesting the second network node to trigger an LTM operation to hand over the UE to the target cell.

[0021] In some embodiments of the present application, the configuration information includes an ID of the target cell.

[0022] In some embodiments of the present application, the reference configuration is a configuration associated with the cell to which the UE is connected when it receives the configuration of the candidate cell related to the LTM operation or the SCGSA operation, or a configuration different from the configuration of all candidate cells related to the LTM operation or the SCGSA operation, or a configuration associated with the candidate cell related to the LTM operation or the SCGSA operation.

[0023] In some embodiments of the present application, the processor is further configured to receive, from the UE via the transceiver, an indication indicating that the configuration information is not to be applied.

[0024] In some embodiments of the present application, the indication includes a cause value indicating an erroneous source cell.

[0025] According to some embodiments of the present application, a method performed by a UE may include: receiving first configuration information related to LTM operation or SCGSA operation; receiving second configuration information related to L3 cell switching; determining whether to apply the second configuration information to perform the L3 cell switching; and in response to determining to apply the second configuration information to perform the L3 cell switching, applying the second configuration information based on the first configuration information to perform the L3 cell switching.

[0026] According to some embodiments of the present application, a method performed by a first network node may include: determining to trigger L3 cell handover of a UE; and transmitting configuration information related to the L3 cell handover to a second network node or the UE. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to describe the manner in which the advantages and features of the present application can be obtained, the description of the present application is presented by reference to specific embodiments of the present application illustrated in the accompanying drawings. These drawings depict only example embodiments of the present application and therefore should not be considered to limit its scope.

[0028] Figure 1 is a schematic diagram illustrating an exemplary wireless communication system according to some embodiments of the present application.

[0029] Figure 2 A flowchart illustrating an exemplary inter-gNB handover procedure according to some embodiments of the present application.

[0030] Figure 3 A flowchart illustrating exemplary intra-gNB-CU and inter-gNB-DU mobility procedures according to some embodiments of the present application.

[0031] Figure 4 A flow chart illustrating an exemplary method for triggering LTM and L3 cell handover according to some embodiments of the present application.

[0032] Figure 5 A flow chart illustrating an exemplary method for triggering SCGSA and L3 cell handover according to some embodiments of the present application.

[0033] Figure 6 A flow chart illustrating an exemplary method for supporting coexistence of LTM and inter-CU L3 primary cell (PCell) switching according to some embodiments of the present application.

[0034] Figure 7 A flowchart illustrating an exemplary method for supporting coexistence of LTM and inter-CU L3 PCell switching according to some other embodiments of the present application.

[0035] Figure 8 An example of a second differential configuration related to L3 cell handover according to some embodiments of the present application is described.

[0036] Figure 9 A flow chart illustrating an exemplary method for supporting coexistence of SCGSA and inter-SN L3 primary-secondary cell (PSCell) handover according to some embodiments of the present application.

[0037] Figure 10 A flow chart illustrating an exemplary method for supporting coexistence of SCGSA and inter-SN L3 PSCell switching according to some other embodiments of the present application.

[0038] Figure 11 An example of a second differential configuration related to L3 cell handover according to some other embodiments of the present application is described.

[0039] Figure 12 A simplified block diagram illustrating an exemplary apparatus for supporting coexistence of LTM / SCGSA and L3 cell handover according to some embodiments of the present application. DETAILED DESCRIPTION

[0040] The detailed description of the accompanying drawings is intended as a description of the preferred embodiments of the present application and is not intended to represent the only form in which the present application can be practiced. It should be understood that the same or equivalent functions can be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present application.

[0041] Although operations are depicted in a particular order in the figures, those skilled in the art will readily recognize that such operations need not necessarily be performed in the particular order shown or in sequential order, or that all illustrated operations need not be performed to achieve a desired result; one or more operations may sometimes be skipped. Furthermore, the figures may schematically depict one or more example processes in the form of flow charts. However, other operations not depicted may be incorporated into the schematically illustrated example processes. For example, one or more additional operations may be performed before, after, concurrently with, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous.

[0042] Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, the embodiments are provided in the context of specific network architectures and new service scenarios (e.g., 3rd Generation Partnership Project (3GPP) LTE and LTE-Advanced, 3GPP 5G NR, 5G-Advanced, 6G, etc.). It is contemplated that as network architectures and new service scenarios evolve, all embodiments in the present application are also applicable to similar technical problems; and further, the terms used in the present application may be changed without affecting the principles of the present application.

[0043] Figure 1 An exemplary wireless communication system 100 is illustrated in accordance with some embodiments of the present application.

[0044] like Figure 1 As shown in FIG, a wireless communication system 100 may include at least one UE 101 and at least one BS 102. Specifically, for illustrative purposes, the wireless communication system 100 includes two UEs 101 (eg, UE 101a and UE 101b) and one BS 102. Although Figure 1 A specific number of UEs 101 and BSs 102 are depicted in FIG. 1 , but it is contemplated that any number of UEs 101 and BSs 102 may be included in the wireless communication system 100 .

[0045] According to some embodiments of the present disclosure, UE 101 may include a computing device, such as a desktop computer, a laptop computer, a personal digital assistant (PDA), a tablet computer, a smart TV (e.g., a TV connected to the Internet), a set-top box, a game console, a security system (including security cameras), an in-vehicle computer, a network device (e.g., a router, a switch, and a modem), or the like.

[0046] According to some other embodiments of the present disclosure, UE 101 may include a portable wireless communication device, a smart phone, a cellular phone, a flip phone, a device with a subscriber identity module, a personal computer, a selective call receiver, or any other device capable of sending and receiving communication signals on a wireless network.

[0047] According to some other embodiments of the present disclosure, UE 101 may include a wearable device, such as a smart watch, a fitness band, an optical head-mounted display, or the like.

[0048] According to some embodiments of the present disclosure, UE 101 may include a vehicle UE (VUE) and / or an energy-saving UE (also known as a power-sensitive UE). Energy-saving UEs may include vulnerable road users (VRUs) that are sensitive to power consumption, public safety UEs (PS-UEs), and / or commercial sidelink UEs (CS-UEs). In embodiments of the present disclosure, VRUs may include pedestrian UEs (P-UEs), cyclist UEs, wheelchair UEs, or other UEs that require energy conservation compared to VUEs.

[0049] Furthermore, UE 101 may be referred to as a subscriber unit, mobile device, mobile station, user, terminal, mobile terminal, wireless terminal, fixed terminal, subscriber station, user terminal or device or described using other terminology used in the art.

[0050] Figure 1 In the embodiment of FIG, both UE 101a and UE 101b are within the coverage of BS 102 and can transmit information or data to BS 102 and receive control information or data from BS 102, for example, via an LTE or NR Uu interface. In other embodiments, one or more of UE 101a and UE 101b may be outside the coverage area of ​​BS 102.

[0051] BSs 102 may be distributed throughout a geographic area. In certain embodiments of the present disclosure, BSs 102 may also be referred to as access points, access terminals, base stations, base units, macrocells, Node Bs, evolved Node Bs (eNBs), generalized Node Bs (gNBs), home Node Bs, relay nodes, or devices, or other terms used in the art. BSs 102 are typically part of a radio access network that may include one or more controllers communicatively coupled to BSs 102.

[0052] The wireless communication system 100 may be compatible with any type of network capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with wireless communication networks, cellular telephone networks, time division multiple access (TDMA)-based networks, code division multiple access (CDMA)-based networks, orthogonal frequency division multiple access (OFDMA)-based networks, LTE networks, 3GPP-based networks, 3GPP 5G networks, satellite communication networks, high altitude platform networks, and / or other communication networks.

[0053] In some embodiments of the present disclosure, the wireless communication system 100 is compatible with the 5G NR of the 3GPP protocol, wherein the BS 102 can transmit data using an orthogonal frequency division multiplexing (OFDM) modulation scheme on the downlink (DL), and the UE 101 can transmit data using a discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM) or cyclic prefix-OFDM (CP-OFDM) scheme on the uplink (UL). However, more generally, the wireless communication system 100 can implement some other open or proprietary communication protocols, such as WiMAX and other protocols.

[0054] In some embodiments of the present disclosure, BS 102 may communicate using other communication protocols, such as the IEEE 802.11 family of wireless communication protocols. Furthermore, in some embodiments of the present disclosure, BS 102 may communicate via a licensed spectrum, while in other embodiments, BS 102 may communicate via an unlicensed spectrum. The present disclosure is not intended to be limited to any particular wireless communication system architecture or protocol implementation. In other embodiments of the present disclosure, BS 102 may communicate with UE 101 using 3GPP 5G protocols.

[0055] In the wireless communication system 100, various types of mobility of the UE 101 may be supported. The following embodiments provide several exemplary types of mobility of the UE.

[0056] Figure 2 An exemplary inter-gNB handover procedure according to some embodiments of the present application is described, in which a UE performs a cell handover from a source cell of a source gNB to a target cell of a target gNB. Figure 2 The procedures described in can be used for inter-gNB cell-level mobility.

[0057] refer to Figure 2 In step 201, the source gNB may initiate a handover and issue a handover request message (e.g., HANDOVER REQUEST as specified in the 3GPP standard profile) to the target gNB via the Xn interface.

[0058] In step 202', the target gNB may perform admission control.

[0059] In step 202, the target gNB may provide the new radio resource control (RRC) configuration as part of a handover request confirm message (e.g., HANDOVER REQUEST ACKNOWLEDGE as specified in the 3GPP standard profile) and transmit the handover request confirm message to the source gNB.

[0060] In step 203, the source gNB may provide the RRC configuration to the UE by forwarding the RRC Reconfiguration message (e.g., RRCReconfiguration as specified in the 3GPP standard profile) received in the Handover Request Confirm message. The RRC Reconfiguration message may include at least one cell ID and all information required to access the target cell, allowing the UE to access the target cell without having to read system information. For some cases, information required for contention-based and contention-free random access may be included in the RRC Reconfiguration message. The information required to access the target cell may include beam-specific information, if available.

[0061] In step 204', the UE may move to the RRC connection of the target gNB.

[0062] In step 204, the UE may reply to the target gNB with an RRC reconfiguration complete message (e.g., RRCReconfigurationComplete as specified in the 3GPP standard profile).

[0063] According to some embodiments of the present application, the internal structure of a base station (e.g., a gNB) can be divided into a centralized unit (CU) and at least one distributed unit (DU). The CU and at least one DU are connected to each other via the F1 interface, as specified in 3GPP standard documents. The RRC layer functionality, Service Data Adaptation Protocol (SDAP) functionality, and Packet Data Convergence Protocol (PDCP) layer functionality are included in the CU. The Radio Link Control (RLC) layer functionality, Medium Access Control (MAC) layer functionality, and Physical (PHY) layer functionality are included in each DU.

[0064] Figure 3 This section describes exemplary intra-gNB-CU and inter-gNB-DU mobility procedures according to some embodiments of the present application. Figure 3 The procedure in can be used for the case when the UE moves from a source gNB-DU to a target gNB-DU within the same gNB-CU.

[0065] refer to Figure 3 In step 300, an UL packet is sent from the UE and forwarded to the gNB-CU via the source gNB-DU; and a DL packet is sent from the gNB-CU and forwarded to the UE via the source gNB-DU.

[0066] In step 301, the UE may send a measurement report message (e.g., MeasurementReport specified in the 3GPP standard profile) to the source gNB-DU.

[0067] In step 302, the source gNB-DU may send an UL RRC message transfer message (e.g., UL RRC MESSAGE TRANSFER as specified in the 3GPP standard profile) to the gNB-CU to convey the received measurement report message.

[0068] In step 302a, the gNB-CU may send a UE CONTEXT MODIFICATION REQUEST message (e.g., a UE CONTEXT MODIFICATION REQUEST message as specified in the 3GPP standard profile) to the source gNB-DU to query for the most recent configuration. In step 302b, the source gNB-DU may respond to the gNB-CU with a UE CONTEXT MODIFICATION RESPONSE message (e.g., a UE CONTEXT MODIFICATION RESPONSE message as specified in the 3GPP standard profile) containing complete configuration information. Steps 302a and 302b are optional.

[0069] In step 303, the gNB-CU may send a UE CONTEXT SETUP REQUEST message (e.g., UE CONTEXT SETUP REQUEST as specified in the 3GPP standard profile) to the target gNB-DU to create a UE context and set up one or more data bearers. The UE CONTEXT SETUP REQUEST message may include handover preparation information (e.g., HandoverPreparationInformation as specified in the 3GPP standard profile).

[0070] In step 304, the target gNB-DU may respond to the gNB-CU with a UE CONTEXT SETUP RESPONSE message (e.g., UE CONTEXT SETUP RESPONSE as specified in the 3GPP standard profile).

[0071] In step 305, the gNB-CU may send a UE CONTEXT MODIFICATION REQUEST message (e.g., UE CONTEXT MODIFICATION REQUEST as specified in the 3GPP standard profile) to the source gNB-DU, including the generated RRC reconfiguration message (e.g., RRCReconfiguration as specified in the 3GPP standard profile) and instructing the UE to stop data transmission. The source gNB-DU may send a DL DATA DELIVERY STATUS frame (e.g., Downlink Data Delivery Status as specified in the 3GPP standard profile) to notify the gNB-CU of unsuccessful transmission of DL data to the UE (if any).

[0072] In step 306, the source gNB-DU may forward the received RRC reconfiguration message to the UE.

[0073] In step 307, the source gNB-DU may respond to the gNB-CU with a UE CONTEXT MODIFICATION RESPONSE message (e.g., UE CONTEXT MODIFICATION RESPONSE as specified in the 3GPP standard profile).

[0074] In step 308, a random access procedure may be performed at the target gNB-DU. The target gNB-DU may optionally send a DL data delivery status frame (e.g., a Downlink Data Delivery Status frame specified in the 3GPP standard profile) to inform the gNB-CU. DL packets (if any) may contain PDCP protocol data units (PDUs) that were not successfully transmitted in the source gNB-DU, and are sent from the gNB-CU to the target gNB-DU.

[0075] In step 309, the UE may respond to the target gNB-DU with an RRC reconfiguration complete message (e.g., RRCReconfigurationComplete as specified in the 3GPP standard profile).

[0076] In step 310, the target gNB-DU may send an UL RRC message transfer message (e.g., UL RRC MESSAGE TRANSFER as specified in the 3GPP standard profile) to the gNB-CU to convey the received RRC Reconfiguration Complete message. DL packets are then sent to the UE. Additionally, UL packets are sent from the UE and forwarded to the gNB-CU via the target gNB-DU.

[0077] In step 311, the gNB-CU may send a UE CONTEXT RELEASE COMMAND message (e.g., UE CONTEXT RELEASE COMMAND as specified in the 3GPP standard profile) to the source gNB-DU.

[0078] In step 312, the source gNB-DU may release the UE context and respond to the gNB-CU with a UE CONTEXT RELEASE COMPLETE message (e.g., UE CONTEXT RELEASE COMPLETE as specified in the 3GPP standard profile).

[0079] In addition to the above procedures, inter-cell LTM may also be supported in 3GPP Release 18. LMT operations may involve the following operations.

[0080] Before receiving the LTM command from a DU (e.g., gNB-DU) of a base station, the UE may be configured with multiple candidate cells (e.g., special cells (SpCells)) or multiple candidate cell groups. The SpCell may be a PCell or a PSCell.

[0081] A cell group can be a master cell group (MCG) or an SCG.

[0082] When the DU of the BS triggers an LTM operation based on the received Layer 1 (L1) measurement result, the DU of the BS may send an LTM command to the UE, for example, via a MAC Control Element (CE) or DL ​​Control Information (DCI).

[0083] The DU of the BS also notifies the CU of the triggering of the LTM operation or the successful execution of the LTM operation. For example, the triggering of the LTM operation may mean that the DU of the BS has sent an LTM command to the UE; and the successful execution of the LTM operation may mean that the UE has successfully switched to the target cell indicated by the LTM command.

[0084] After performing the LTM operation triggered by the DU of the BS, the UE does not release the configuration of multiple candidate cells or multiple candidate cell groups.

[0085] Unlike LTM, an L3 cell (e.g., PCell / PSCell) change (or handover) can be triggered by a CU (e.g., a gNB-CU) of a BS based on received L3 measurement results. Assuming LTM is configured (e.g., multiple candidate cells or cell groups are configured or prepared at both the UE and the DU) and LTM operation can be triggered by the DU at any time, it is possible that the CU can begin preparing for or triggering an L3 cell handover based on received L3 measurement results without being aware that LTM operation has been triggered by the DU. In such cases, the delta configuration prepared for the L3 cell handover may become outdated due to the CU assuming the wrong source cell.

[0086] Figure 4 An exemplary method for triggering LTM and L3 cell handover according to some embodiments of the present application is described.

[0087] refer to Figure 4 , the UE is initially connected to a source cell (e.g., cell 1). In operation 401, LTM may be configured for the UE. In operation 402, the source CU may determine to trigger an L3 cell handover from the UE to a target CU based on the received L3 measurement results. In operation 403, the source CU may transmit the handover request message described above to the target CU via the Xn interface. In response to the handover request message, in operation 404, the target CU may generate a delta configuration based on the UE's assumed source cell (i.e., cell 1), and then transmit the delta configuration to the source CU.

[0088] However, after operation 403, in operation 405, the source DU may trigger LTM operation based on the received L1 measurement results and hand over the UE from cell 1 to a new cell (e.g., cell 2). In operation 406, the source DU may notify the source CU of the triggering of the LTM operation. Operation 406 may occur before, after, or simultaneously with operation 404 and before the source CU transmits the delta configuration to the UE.

[0089] In such cases, the differential configuration prepared by the target CU is no longer valid because the UE's current connection source cell becomes cell 2, while the differential configuration is generated based on cell 1. To resolve the conflict between LTM and L3 cell handover, the following solution can be adopted.

[0090] One solution is that the source CU can cancel the initiated handover request and restart another handover request with the updated source cell. Figure 4 As shown in FIG4 , in operation 407, the source CU may transmit an indication to the target CU to cancel the initiated handover request (i.e., the handover request associated with the handover request message transmitted in operation 403). In operation 408, the source CU may transmit an updated handover request message with the updated source cell (i.e., cell 2) to the target CU. In response to receiving the updated handover request message, in operation 409, the target CU may generate an updated delta configuration based on cell 2 and transmit the updated delta configuration to the source CU. Clearly, canceling and restarting an L3 cell handover due to LTM will introduce additional handover delay. In some cases, in operation 410, another LTM operation may be triggered, and thus, operations 407 through 409 may be performed again, which may further increase handover delay.

[0091] Another solution is that the source CU deconfigures LTM at the UE before the UE triggers L3 cell handover (or change). However, this solution requires additional RRC reconfiguration signaling on the Uu interface and also introduces additional handover delay.

[0092] In view of the above, a new solution is needed to solve the aforementioned problem of coexistence between LTM and L3 cell handover.

[0093] In addition to LTM, SCGSA may also be supported in wireless communication networks. SCGSA operations may involve the following operations.

[0094] The UE is configured with candidate PSCells, each associated with an execution condition. For example, the execution condition may be included in a conditional configuration associated with the candidate PSCell. For example, the execution condition may be that the link quality of the candidate PSCell is better than the link quality of the source PSCell by more than a certain threshold.

[0095] When the execution condition associated with a candidate PSCell is met, for example, the link quality of this candidate PSCell is better than that of the source PSCell by more than a certain threshold, the UE may perform a conditional PSCell change or PSCell addition procedure on this candidate PSCell.

[0096] • After completing the conditional PSCell change or addition procedure, the UE may not release the conditional configuration of other candidate PSCells for subsequent conditional PSCell changes, and the UE continues to evaluate the execution conditions of other candidate PSCells.

[0097] • When the execution condition associated with another candidate PScell ​​is met, the UE may perform a conditional PSCell change towards another candidate PSCell.

[0098] In some cases, assuming that SCGSA has been configured for the UE, it is possible that a master node (MN) or a secondary node (SN) may start preparing or triggering an L3 cell (e.g., PSCell) handover (or change) based on received L3 measurement results without knowing that SCGSA has been performed. In such cases, the differential configuration prepared for the L3 cell handover may be outdated due to the MN or SN assuming the wrong source cell.

[0099] Figure 5 An exemplary method for triggering SCGSA and L3 cell handover according to some embodiments of the present application is described.

[0100] refer to Figure 5 , the UE is initially connected to the source cell of the source SN (e.g., PSCell 1). In operation 501, the SCGSA may be configured for the UE. In operation 502 (which is an optional operation), the source SN may transmit an SN change message (e.g., SN Change Required specified in the 3GPP standard profile) indicating the need to change the SN to the MN. In operation 503, the MN may determine to change the SN to the target SN and send an SN addition request message (e.g., SN AdditionRequest specified in the 3GPP standard profile) to the target SN via the Xn interface. In response to receiving the SN addition request message, in operation 504, the target SN may generate a PSCell change differential configuration based on the assumed source cell (i.e., PSCell 1), and transmit the PSCell change differential configuration to the MN via an SN addition confirmation message (e.g., SN Addition Acknowledge specified in the 3GPP standard profile).

[0101] However, after operation 503, in operation 505, the UE may switch to a candidate PSCell (e.g., PSCell 2) based on the SCGSA, e.g., in response to satisfying an execution condition associated with the candidate PSCell. Operation 505 may occur before, after, or simultaneously with operation 504, and before the MN transmits a PSCell change delta configuration to the UE.

[0102] In such cases, the differential configuration prepared by the target SN is no longer valid because the UE's current connection source cell becomes PSCell 2, while the differential configuration is generated based on PSCell 1. To resolve the conflict between SCGSA and L3 cell (eg, PSCell) handover, the following solution can be adopted.

[0103] One solution is for the MN or source SN to provide the updated source PSCell or SCG configuration to the target SN. Figure 5 As shown in FIG, in operation 506, the MN may transmit an SN Modification Request message (e.g., an SN Modification Request specified in a 3GPP standard profile) to the target SN to provide the updated source PSCell (i.e., PSCell 2) to the target SN. In response to receiving the SN Modification Request message, in operation 507, the target SN may generate an updated PSCell change delta configuration based on PSCell 2 and transmit the updated PSCell change delta configuration to the MN. Obviously, reinitiating L3 cell handover due to SCGSA will introduce additional handover delay. In some cases, in operation 508, the UE may switch to another candidate PSCell (e.g., PSCell 3) based on the SCGSA, e.g., in response to satisfying an execution condition associated with the other candidate PSCell. Therefore, operations 506 and 507 may be performed again, which may further increase handover delay.

[0104] Another solution is that the MN or source SN cancels the SCGSA at the UE before the UE triggers L3 cell (eg PSCell) handover (or change). However, this solution requires additional RRC reconfiguration signaling on the Uu interface and also introduces additional handover delay.

[0105] In view of the above, a new solution is needed to address the aforementioned problem of coexistence between SCGSA and L3 cell handover.

[0106] In view of the above, embodiments of the present application propose solutions for supporting the coexistence of different types of mobility. For example, embodiments of the present application propose detailed procedures and related signaling for supporting the coexistence of LTM and L3 PCell or PSCell switching (or change). As another example, embodiments of the present application propose detailed procedures and related signaling for supporting the coexistence of SCGSA and L3 PSCell switching (or change). The solutions in the embodiments of the present application can address at least the above-mentioned issues. More details about the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0107] Based on different types of mobility, the coexistence scenario may include the following two cases, namely, Case 1 and Case 2.

[0108] Case 1

[0109] In case 1, LTM and L3 cell handover (e.g., L3 PCell handover or PSCell handover) can coexist. L3 cell handover in the embodiments of this application may also be referred to as L3 cell change. The following embodiments provide several solutions for supporting the coexistence of LTM and L3 cell handover.

[0110] Example 1

[0111] In embodiment 1, a UE may receive first configuration information related to LTM operation (also referred to as LTM configuration). The first configuration information may be associated with a reference configuration related to LTM operation. In some embodiments, the reference configuration may be a configuration associated with the cell to which the UE is connected when it receives the first configuration information. In some embodiments, the first configuration information may explicitly include the reference configuration. In some other embodiments, the first configuration information may implicitly indicate the reference configuration. For example, the first configuration information may indicate the use of a specific configuration as the reference configuration without explicitly providing the specific configuration. The reference configuration may be stored on the UE. When a first network node, such as a CU of a BS (e.g., a gNB-CU), prepares an L3 cell handover (which may be an intra-CU L3 cell handover or an inter-CU L3 cell handover), it may generate a delta configuration on top of the reference configuration. The generated delta configuration may then be sent to the UE via an RRC message (e.g., including the information element ReconfigurationWithSync). The UE may then apply the differential configuration based on (or on top of) the stored reference configuration to perform L3 cell handover, regardless of which cell the UE is currently connected to, i.e., regardless of the current source cell when the differential configuration for L3 cell handover is received by the UE.

[0112] The technical solution provided by Example 1 is applicable to both intra-CU (or intra-BS) and inter-CU (or inter-BS) L3 cell handover scenarios.

[0113] Figure 6 An exemplary method for supporting coexistence of LTM and inter-CU L3 PCell switching according to some embodiments of the present application is described. Figure 6 The method described in the specification can be performed by a UE and three network nodes (e.g., a first network node, a second network node, and a third network node). In some embodiments of the present application, the first network node can be a CU of a base station (e.g., a source CU) or other devices with similar functions. The second network node can be a DU of a base station (e.g., a source DU) or other devices with similar functions. The third network node can be a CU of another base station (e.g., a target CU) or other devices with similar functions. Although the method is described at the system level, those skilled in the art will understand that the method implemented in the UE and the three network nodes can be implemented separately in other devices with similar functions and incorporated therein.

[0114] refer to Figure 6 , the UE is initially connected to a source cell (e.g., cell 1). In operation 601, LTM may be configured for the UE. For example, in operation 601, the UE may receive first configuration information related to LTM operation (e.g., for LTM). The first configuration information may be associated with a reference configuration related to LTM operation.

[0115] In some embodiments, the reference configuration may be a configuration associated with the cell to which the UE is connected when the UE receives the first configuration information. In such embodiments, the first configuration information may include a set of delta configurations related to LTM operation, each of which is associated with a respective candidate cell within a set of candidate cells related to LTM operation and is generated based on (or on top of) the reference configuration. A set of elements in the embodiments of the present application may refer to one or more elements. The candidate cell may be an SPCell, such as a PCell or a PSCell.

[0116] In some embodiments, the reference configuration may be a configuration that is different from the configurations of all candidate cells associated with LTM operation. In such embodiments, the first configuration information may include the reference configuration and a set of delta configurations associated with LTM operation, and each of the set of delta configurations is associated with a respective candidate cell within a set of candidate cells associated with LTM operation and is generated based on (or on top of) the reference configuration.

[0117] In some embodiments, the reference configuration may be a configuration of a candidate cell associated with LTM operation. In such embodiments, the first configuration information may include a set of configurations associated with LTM operation, with each of the set of configurations being associated with a respective candidate cell within a set of candidate cells associated with LTM operation. The first configuration information may indicate which configuration in the set of configurations is the reference configuration. In such embodiments, the other configurations in the set of configurations may be delta configurations generated based on (or on top of) the reference configuration.

[0118] In operation 602 , the first network node may determine to trigger an L3 cell handover of the UE to a target cell (eg, cell 3 ) based on an L3 measurement result, where the cell 3 belongs to a third network node.

[0119] In operation 603, the first network node may transmit a first message (eg, a handover request message) to the third network node, for example, via an Xn interface. The first message may include a reference configuration.

[0120] In response to the first message, the third network node may generate a delta configuration for L3 cell handover on top of (or based on) the reference configuration. Then, in operation 604, the third network node may transmit a second message (e.g., a handover request confirmation message) including the delta configuration to the first network node, for example, via an Xn interface.

[0121] After operation 603, in operation 605, the second network node may trigger an LTM operation based on the received L1 measurement result and hand over the UE from cell 1 to a new cell (eg, cell 2). In operation 606, the second network node may notify the first network node of the triggering of the LTM operation.

[0122] In operation 607, the first network node may transmit second configuration information related to L3 cell handover to the second network node, for example, via an F1 interface. The second configuration information may include a delta configuration generated by the third network node. For example, the second configuration information may be included in a UE Context Modification Request message.

[0123] In operation 608, the second network node may transmit second configuration information to the UE. For example, the second configuration information may be included in an RRC message (eg, an RRC reconfiguration message) with an information element ReconfigurationWithSync transmitted from the second network node to the UE.

[0124] After receiving the second configuration information, the UE may determine whether to apply the second configuration information to perform L3 cell handover. For example, the UE may parse the second configuration information to determine whether the second configuration information is for L3 cell handover.

[0125] In response to determining to apply the second configuration information to perform L3 cell handover, the UE may apply the second configuration information based on (or on top of) the first configuration information to perform L3 cell handover in operation 609. For example, the UE may apply the delta configuration included in the second configuration information based on (or on top of) the reference configuration to perform L3 cell handover, regardless of which cell the UE is currently connected to. For example, the UE may initiate a random access channel (RACH) procedure for cell 3 as instructed by the delta configuration.

[0126] In response to successfully performing the RACH procedure, in operation 610 , the UE may transmit an RRC completion message to the third network node (ie, cell 3 ).

[0127] In operation 611, the UE may release all configurations related to the LTM operation after performing L3 cell handover.

[0128] although Figure 6 L3 PCell handover is shown as an example, but similar operations are also applicable to L3 PSCell handover. For inter-CU L3 PSCell handover, the difference is that the first message transmitted in operation 603 may be an SN Add Request message, and the second message transmitted in operation 604 may be an SN Add Request Acknowledge message.

[0129] Example 2

[0130] In embodiment 2, a UE may receive first configuration information related to LTM operation (also referred to as LTM configuration). The first configuration information may include a set of configurations related to LTM operation, and each of the set of configurations is associated with a respective candidate cell (PCell or PSCell) within a set of candidate cells related to LTM operation.

[0131] In embodiment 2, when a first network node (e.g., a source CU) triggers an inter-CU L3 cell handover, the first network node may transmit one or more first messages to a third network node (e.g., a target CU), wherein the one or more first messages may include the set of configurations related to LTM operations.

[0132] As an example, the first network node may transmit one first message including all of the set of configurations.As another example, the first network node may transmit multiple first messages, and each of the multiple first messages may include a respective configuration within the set of configurations.

[0133] The third network node may transmit one or more second messages to the first network node in response to the one or more first messages. The one or more second messages may include a set of delta configurations, and each delta configuration within the set of delta configurations is associated with a respective candidate cell within the set of candidate cells and is generated based on (or on top of) a configuration within the set of configurations associated with the respective candidate cell.

[0134] As an example, the third network node may transmit one second message including all of the set of delta configurations.As another example, the third network node may transmit multiple second messages, and each second message in the multiple second messages includes a corresponding delta configuration within the set of delta configurations.

[0135] In some examples, the inter-CU L3 cell handover may be an inter-CU L3 PCell handover. In such examples, the set of candidate cells may be a set of candidate PCells, and the set of configurations may be a set of configurations associated with the set of candidate PCells. In this example, the first message may be a handover request message, and the second message may be a handover request confirmation message.

[0136] In some other examples, the inter-CU L3 cell handover may be an inter-CU L3 PSCell handover. In such examples, the set of candidate cells may be a set of candidate PSCells, and the set of configurations may be a set of configurations associated with the set of candidate PSCells. In this example, the first message may be a SN Add Request message, and the second message may be a SN Add Request Acknowledge message.

[0137] After receiving the set of differential configurations, it is the first network node that determines which differential configuration to send to the UE based on the UE's current connection source cell. For example, after receiving the set of differential configurations, the first network node may determine the current cell to which the UE is connected, where the current cell may be within the set of candidate cells. The first network node may then transmit second configuration information including the differential configuration associated with the current cell within the set of differential configurations. The UE may then apply the differential configuration based on (or on top of) the configuration associated with the current cell to perform L3 cell handover.

[0138] Figure 7 An exemplary method for supporting coexistence of LTM and inter-CU L3 PCell switching according to some embodiments of the present application is described. Figure 7The method described in the specification can be performed by a UE and three network nodes (e.g., a first network node, a second network node, and a third network node). In some embodiments of the present application, the first network node can be a CU of a base station (e.g., a source CU) or other devices with similar functions. The second network node can be a DU of a base station (e.g., a source DU) or other devices with similar functions. The third network node can be a CU of another base station (e.g., a target CU) or other devices with similar functions. Although the method is described at the system level, those skilled in the art will understand that the method implemented in the UE and the three network nodes can be implemented separately in other devices with similar functions and incorporated therein.

[0139] refer to Figure 7 , the UE is initially connected to a source cell (e.g., cell 1). In operation 701, LTM may be configured for the UE. For example, in operation 701, the UE may receive first configuration information. The definition of the first configuration information provided in the foregoing content of embodiment 2 is applicable here.

[0140] In operation 702 , the first network node may determine to trigger an L3 cell handover of the UE to a target cell (eg, cell 3 ) based on an L3 measurement result, where the cell 3 belongs to a third network node.

[0141] In operation 703, the first network node may transmit a first message (e.g., a handover request message) including a set of configurations to the third network node, for example, via an Xn interface. Each of the set of configurations may be associated with a respective candidate cell (e.g., a PCell) within a set of candidate cells (e.g., a PCell) associated with LTM operation.

[0142] In response to the first message, the third network node may generate a set of delta configurations, and each delta configuration within the set of delta configurations is associated with a corresponding candidate cell within the set of candidate cells and is generated based on (or on top of) the configuration associated with the corresponding candidate cell within the set of configurations.

[0143] Then, in operation 704, the third network node may transmit a second message (e.g., a handover request confirm message) including the set of delta configurations to the first network node, for example, via an Xn interface. For example, the set of delta configurations may include {DeltaConfig1 with assumed cell #1 as the source cell, DeltaConfig2 with assumed cell #2 as the source cell, ..., DeltaConfigN with assumed cell #N as the source cell}, where N is the number of candidate cells included in the set of candidate cells.

[0144] After operation 703, in operation 705, the second network node may trigger an LTM operation based on the received L1 measurement result and hand over the UE from cell 1 to a new cell (eg, cell 2). In operation 706, the second network node may notify the first network node of the triggering of the LTM operation.

[0145] The first network node may determine the current cell to which the UE is connected (e.g., cell 2), where cell 2 is within the set of candidate cells. Then, in operation 707, the first network node may transmit second configuration information to the second network node, for example, via an F1 interface. The second configuration information may include a delta configuration associated with cell 2 within the set of delta configurations and generated based on (or on top of) the configuration associated with cell 2. For example, the second configuration information may be included in a UE context modification request message.

[0146] In operation 708, the second network node may transmit second configuration information to the UE. For example, the second configuration information may be included in an RRC message (eg, an RRC reconfiguration message) with an information element ReconfigurationWithSync transmitted from the second network node to the UE.

[0147] After receiving the second configuration information, the UE may determine whether to apply the second configuration information to perform L3 cell handover. For example, the UE may parse the second configuration information to determine whether the second configuration information is for L3 cell handover.

[0148] In response to determining to apply the second configuration information to perform L3 cell handover, the UE may apply the second configuration information based on the first configuration information to perform L3 cell handover in operation 709. For example, the UE may apply the delta information included in the second configuration information based on (or on top of) the configuration associated with cell 2 (the configuration associated with cell 2 may be included in the first configuration information) to perform L3 cell handover to cell 3. For example, the UE may initiate a RACH procedure for cell 3 as instructed by the delta configuration.

[0149] In response to successfully performing the RACH procedure, in operation 710 , the UE may transmit an RRC completion message to the third network node (ie, cell 3 ).

[0150] In operation 711, the UE may release all configurations related to the LTM operation after performing L3 cell handover.

[0151] Example 3

[0152] In embodiment 3, a UE may receive first configuration information related to LTM operation (also referred to as LTM configuration). The first configuration information may be associated with a reference configuration related to LTM operation and include a set of configurations related to LTM operation. Each of the set of configurations is associated with a corresponding candidate cell within a set of candidate cells, and each of the set of configurations may be a corresponding first delta configuration associated with the corresponding candidate cell, or may be a reference configuration.

[0153] As an example, the reference configuration may be a configuration associated with the cell to which the UE is connected when the UE receives the first configuration information. In this example, each of the set of configurations included in the first configuration information may be a corresponding first delta configuration associated with a respective candidate cell (e.g., a PCell or PSCell) within the set of candidate cells and generated based on (or on top of) the reference configuration.

[0154] As another example, the reference configuration may be a configuration that is different from the configurations of all candidate cells associated with LTM operation. In this example, the first configuration information may include both the reference configuration and the set of configurations, and each of the set of configurations may be a corresponding first delta configuration associated with a respective candidate cell (e.g., a PCell or PSCell) within the set of candidate cells and generated based on (or on top of) the reference configuration.

[0155] As another example, the reference configuration may be a configuration of a candidate cell associated with LTM operation. In this example, each of the set of configurations included in the first configuration information is associated with a corresponding candidate cell (e.g., a PCell or PSCell) within a set of candidate cells associated with LTM operation. The first configuration information may indicate which configuration in the set of configurations is the reference configuration. Each of the other configurations in the set of configurations may be a corresponding first delta configuration associated with the corresponding candidate cell and generated based on (or on top of) the reference configuration.

[0156] In Embodiment 3, a first network node (e.g., a CU) may determine to trigger an L3 cell handover for a UE based on an L3 measurement result. The first network node may determine that a target cell for the L3 cell handover is within the set of candidate cells associated with the LTM operation. Embodiment 3 may further include Embodiment 3-1 and Embodiment 3-2.

[0157] Example 3-1

[0158] In embodiment 3-1, the first network node may generate the second delta configuration on top of at least one of the reference configuration or the first delta configuration associated with the target cell within the set of configurations.

[0159] For example, if the target cell is associated with a first delta configuration, the first network node may generate a second delta configuration based on the reference configuration and the first delta configuration associated with the target cell. As another example, if the target cell is a candidate cell whose configuration is indicated as the reference configuration, the first network node may generate the second delta configuration based on the reference configuration.

[0160] Then, the first network node may transmit second configuration information including the second differential configuration to the second network node (eg, DU of the BS) via the F1 interface. For example, the second configuration information may be included in a UE context modification request message.

[0161] Then, the second network node may transmit the second configuration information to the UE.For example, the second configuration information may be included in an RRC message (eg, an RRC reconfiguration message) with an information element ReconfigurationWithSync transmitted from the second network node to the UE.

[0162] After receiving the second configuration information, the UE may determine whether to apply the second configuration information to perform L3 cell handover. For example, the UE may parse the second configuration information to determine whether the second configuration information is for L3 cell handover.

[0163] In response to determining to apply the second configuration information to perform L3 cell handover, the UE may apply the second configuration information based on the first configuration information to perform L3 cell handover. For example, the UE may apply the second delta configuration based on (or on top of) at least one of the reference configuration or the first delta configuration associated with the target cell to perform L3 cell handover to the target cell.

[0164] As an example, if the target cell is associated with a first delta configuration, the UE may apply a second delta configuration based on (or on top of) the reference configuration and the first delta configuration associated with the target cell. As an example, if the target cell is a candidate cell whose configuration is indicated as a reference configuration, the UE may apply the second delta configuration based on (or on top of) the reference configuration.

[0165] Figure 8 An example of a second differential configuration related to L3 cell handover according to some embodiments of the present application is described.

[0166] exist Figure 8In the example of FIG, it is assumed that the UE has been configured with two candidate cells associated with (or for) LTM operation (e.g., cell 1 and cell 2). The first configuration information received by the UE may include a reference configuration associated with (or for LTM) the LTM operation and a corresponding first delta configuration associated with cell 1 and a corresponding first delta configuration associated with cell 2 associated with the LTM operation. The UE is currently connected to cell 1. When the CU of the BS (e.g., gNB-CU) determines to trigger an L3 cell handover of the UE to hand over the UE from cell 1 to cell 2, the CU may provide a second delta configuration for the L3 cell handover to cell 2, such as Figure 8 , which is shown on top of {reference configuration related to LTM operation + first differential configuration associated with cell 2}. In this way, the signaling overhead on the F1 interface and Uu interface for L3 cell handover can be reduced. The UE applies the received second differential configuration in the form of {reference configuration related to LTM operation + first differential configuration associated with cell 2 + second differential configuration for L3 cell handover to cell 2} to perform L3 cell handover to cell 2.

[0167] Example 3-2

[0168] In embodiment 3-2, the first network node (e.g., CU) may determine that the configuration associated with the LTM operation associated with the target cell (which is a candidate cell within the set of candidate cells associated with the LTM operation) can be reused. Subsequently, the first network node may not generate the second delta configuration as described above.

[0169] In some instances of Embodiment 3-2, a first network node may transmit second configuration information to a second network node (e.g., a DU of a base station) to request the second network node to trigger an L3 cell handover of the UE to a target cell. The second configuration information may be transmitted via an F1 interface. For example, the second configuration information may include an ID of the target cell. For example, the second configuration information may be included in a UE Context Modification Request message.

[0170] Then, the second network node may transmit second configuration information to the UE instructing the UE to perform L3 cell handover to the target cell.

[0171] After receiving the second configuration information, the UE may determine whether to apply the second configuration information to perform L3 cell handover. For example, the UE may parse the second configuration information to determine whether the second configuration information is for L3 cell handover.

[0172] In response to determining to apply the second configuration information to perform L3 cell handover, the UE may apply the second configuration information based on the first configuration information to perform L3 cell handover. For example, the UE may apply at least one of a reference configuration or a first delta configuration associated with a target cell within the set of configurations to perform L3 cell handover to the target cell.

[0173] As an example, if the target cell is associated with a first delta configuration within the set of configurations, the UE may apply the first delta configuration based on (or on top of) the reference configuration to perform L3 cell handover to the target cell. As an example, if the configuration of the target cell is indicated as a reference configuration, the UE may apply the reference configuration to perform L3 cell handover to the target cell.

[0174] In some other examples, the first network node may transmit second configuration information to the second network node (e.g., a DU of a base station) requesting the second network node to trigger an LTM operation to handover the UE to a target cell. The second configuration information may be transmitted via the F1 interface. For example, the second configuration information may include an ID of the target cell. For example, the second configuration information may be included in a UE Context Modification Request message. For example, the second configuration information may be an LTM request that includes at least the ID of the target cell.

[0175] Then, the second network node may transmit an LTM command via MAC CE or DCI to instruct the UE to perform an LTM operation on the target cell.

[0176] After receiving the LTM command, the UE may perform an LTM operation to switch from the source cell to the target cell.

[0177] Example 4

[0178] In embodiment 4, the UE may receive first configuration information related to LTM operation. For example, the first configuration information may include a configuration of a set of candidate cells related to LTM operation. As another example, the first configuration information may be associated with a reference configuration and include a set of delta configurations, and each of the set of delta configurations may be associated with a corresponding candidate cell within a set of candidate cells related to LTM operation. The reference configuration may be a configuration associated with the cell to which the UE is connected when it receives the first configuration information, or a configuration that is different from the configuration of all candidate cells related to LTM operation, or a configuration of candidate cells related to LTM operation. All definitions regarding the first configuration information related to LTM operation provided to the UE in embodiments 1 to 3 are applicable here.

[0179] The UE may also receive second configuration information related to L3 cell handover to the target cell.

[0180] The UE may determine whether to apply the second configuration information to perform L3 cell switching. For example, the UE may determine not to apply the second configuration information to perform L3 cell switching in at least one of the following situations:

[0181] The UE has been handed over to a cell (e.g., a PCell or PSCell) according to an LTM command within a certain time period, and the cell is different from the target cell (e.g., PCell or PSCell) for L3 cell handover indicated by the second configuration information. For example, the time period can be a fixed value, such as 1000 ms, or can be a value configured by the network.

[0182] The source cell (eg, PCell or PSCell) for L3 cell handover indicated by the second configuration information is different from the cell (eg, PCell or PSCell) to which the UE is currently connected.

[0183] In some embodiments, the UE may transmit an indication to the first network node (e.g., a source CU of a BS) or the second network node (e.g., a DU of a BS) indicating that the second configuration information is not to be applied or is to be ignored. For example, the indication may be an RRC message. For example, the indication may include a new cause value indicating an erroneous source cell.

[0184] Upon consideration, a person skilled in the art would expect that a solution similar to that described with respect to Case 1 may be applicable to situations where a candidate cell is replaced with a candidate cell group (e.g., a candidate MCG or SCG) and the (delta) configuration associated with the candidate cell is replaced with the (delta) configuration associated with the candidate cell group.

[0185] Case 2

[0186] In case 2, SCGSA and L3 cell handover (eg, L3 PSCell handover) can coexist. The following embodiments provide several solutions for supporting the coexistence of SCGSA and L3 cell handover.

[0187] Example 1

[0188] In embodiment 1', the UE may receive first configuration information related to SCGSA operation (also referred to as SCGSA configuration). The first configuration information may be associated with a reference configuration related to SCGSA operation. In some embodiments, the first configuration information may explicitly include the reference configuration. In some other embodiments, the first configuration information may implicitly indicate the reference configuration. For example, the first configuration information may indicate the use of a specific configuration as the reference configuration without explicitly providing the specific configuration. The reference configuration may be stored on the UE. When the MN or SN prepares for an L3 cell handover (which may be an intra-SN L3 cell handover or an inter-SN L3 cell handover), it may generate a differential configuration on top of the reference configuration. The generated differential configuration may then be sent to the UE via an RRC message (e.g., which includes an information element ReconfigurationWithSync). The UE may then apply the differential configuration based on (or on top of) the stored reference configuration to perform the L3 cell handover, regardless of which cell the UE is currently connected to, i.e., regardless of the current source cell when the differential configuration for the L3 cell handover is received by the UE.

[0189] The technical solution provided by Example 1 is applicable to both intra-SN and inter-SN L3 cell handover scenarios.

[0190] Figure 9 An exemplary method for supporting coexistence of SCGSA and inter-SN L3 PSCell switching according to some embodiments of the present application is described. Figure 9 The method described in the present application can be performed by a UE and three network nodes (e.g., a first network node, a second network node, and a third network node). In some embodiments of the present application, the first network node can be an MN or other device with similar functionality. The second network node can be a source SN or other device with similar functionality. The third network node can be a target SN or other device with similar functionality. Although the method is described at the system level, those skilled in the art will appreciate that the method implemented in the UE and the three network nodes can be implemented separately in other devices with similar functionality and incorporated therein.

[0191] refer to Figure 9 , the UE is initially connected to a source cell (e.g., cell 1). In operation 901, SCGSA may be configured for the UE. For example, in operation 901, the UE may receive first configuration information related to SCGSA operation (e.g., for SCGSA). The first configuration information may be associated with a reference configuration related to SCGSA operation.

[0192] In some embodiments, the reference configuration may be a configuration associated with the cell to which the UE is connected when the UE receives the first configuration information. In such embodiments, the first configuration information may include a set of delta configurations related to SCGSA operation, each of which is associated with a respective candidate cell within a set of candidate cells related to SCGSA operation and is generated based on (or on top of) the reference configuration. The candidate cell may be a PSCell.

[0193] In some embodiments, the reference configuration may be a configuration that is different from the configurations of all candidate cells associated with SCGSA operation. In such embodiments, the first configuration information may include the reference configuration and a set of delta configurations associated with SCGSA operation, where each of the set of delta configurations is associated with a respective candidate cell within a set of candidate cells associated with SCGSA operation and is generated based on (or on top of) the reference configuration.

[0194] In some embodiments, the reference configuration may be a configuration of a candidate cell associated with SCGSA operation. In such embodiments, the first configuration information may include a set of configurations associated with SCGSA operation, with each of the set of configurations associated with a respective candidate cell within a set of candidate cells associated with SCGSA operation. The first configuration information may indicate which configuration in the set of configurations is the reference configuration. In such embodiments, the other configurations in the set of configurations may be delta configurations generated based on (or on top of) the reference configuration.

[0195] The first network node or the second network node may determine to trigger an L3 cell handover of the UE to a target cell (eg, cell 3) based on the L3 measurement result, where cell 3 belongs to the third network node.

[0196] For example, in operation 902 (which is an optional operation and may be performed if the second network node determines to trigger L3 switching, and may not be performed if the first network node determines to trigger L3 switching), the second network node may transmit a message indicating a change of SN (e.g., an SN change required message) to the first network node.

[0197] In operation 903, the first network node may transmit a first message (eg, an SN add request message) to the third network node, for example, via an Xn interface. The first message may include a reference configuration.

[0198] In response to the first message, the third network node may generate a differential configuration for L3 cell handover on top of (or based on) the reference configuration. Then, in operation 904, the third network node may transmit a second message (e.g., an SN add request confirm message) including the differential configuration to the first network node, for example, via an Xn interface.

[0199] After operation 903 , in operation 905 , the UE may switch to a candidate cell (eg, cell 2 ) based on the SCGSA configuration, eg, in response to satisfying an execution condition associated with the candidate cell.

[0200] At operation 906, the first network node may transmit second configuration information related to L3 cell handover to the UE. The second configuration information may include a delta configuration generated by the third network node. For example, the second configuration information may be included in an RRC message (e.g., an RRC reconfiguration message) with an information element "ReconfigurationWithSync" transmitted from the first network node to the UE.

[0201] After receiving the second configuration information, the UE may determine whether to apply the second configuration information to perform L3 cell handover. For example, the UE may parse the second configuration information to determine whether the second configuration information is for L3 cell handover.

[0202] In response to determining to apply the second configuration information to perform L3 cell handover, the UE may apply the second configuration information based on (or on top of) the first configuration information to perform L3 cell handover in operation 907. For example, the UE may apply the differential configuration included in the second configuration information based on (or on top of) the reference configuration to perform L3 cell handover, regardless of which cell the UE is currently connected to. For example, the UE may initiate a RACH procedure for cell 3 as instructed by the differential configuration.

[0203] In response to successfully performing the RACH procedure, in operation 908, the UE may transmit an RRC completion message to the first network node.

[0204] In operation 909 (which is an optional operation and may be performed if the second network node determines to trigger L3 handover and may not be performed if the first network node determines to trigger L3 handover), the first network node may transmit an SN change confirm message to the second network node.

[0205] In operation 910 , the first network node may transmit an SN reconfiguration complete message to the third network node.

[0206] In operation 911 , the UE may release all configurations related to the SCGSA operation after performing L3 cell handover.

[0207] Example 2

[0208] In embodiment 2', the UE may receive first configuration information related to SCGSA operation (also referred to as SCGSA configuration). The first configuration information may include a set of configurations related to SCGSA operation, and each of the set of configurations is associated with a corresponding candidate cell (e.g., PSCell) within a set of candidate cells (e.g., PSCell) related to SCGSA operation.

[0209] In embodiment 2', when a first network node (e.g., MN) or a second network node (e.g., source SN) triggers an inter-SN L3PSCell handover, the first network node may transmit one or more first messages to a third network node (e.g., target SN), wherein the one or more first messages may include the set of configurations related to SCGSA operation.

[0210] As an example, the first network node may transmit a first message including all of the set of configurations. As another example, the first network node may transmit multiple first messages, and each of the multiple first messages may include a corresponding configuration within the set of configurations. For example, the first message may be an SN add request message.

[0211] The third network node may transmit one or more second messages to the first network node in response to the one or more first messages. The one or more second messages may include a set of delta configurations, and each delta configuration within the set of delta configurations is associated with a respective candidate cell within the set of candidate cells and is generated based on (or on top of) a configuration within the set of configurations associated with the respective candidate cell.

[0212] As an example, the third network node may transmit a single second message that includes all of the set of delta configurations. As another example, the third network node may transmit multiple second messages, each of which includes a corresponding delta configuration within the set of delta configurations. For example, the second message may be an SN Add Request Confirmation message.

[0213] After receiving the set of differential configurations, it is the first network node that determines which differential configuration to send to the UE based on the UE's current connection source cell. For example, after receiving the set of differential configurations, the first network node may determine the current cell to which the UE is connected, where the current cell may be within the set of candidate cells. The first network node may then transmit second configuration information including the differential configuration associated with the current cell within the set of differential configurations. The UE may then apply the differential configuration based on (or on top of) the configuration associated with the current cell to perform L3 cell handover.

[0214] Figure 10An exemplary method for supporting coexistence of SCGSA and inter-SN L3 PSCell switching according to some embodiments of the present application is described. Figure 10 The method described in the present application can be performed by a UE and three network nodes (e.g., a first network node, a second network node, and a third network node). In some embodiments of the present application, the first network node can be an MN or other device with similar functionality. The second network node can be a source SN or other device with similar functionality. The third network node can be a target SN or other device with similar functionality. Although the method is described at the system level, those skilled in the art will appreciate that the method implemented in the UE and the three network nodes can be implemented separately in other devices with similar functionality and incorporated therein.

[0215] refer to Figure 10 , the UE is initially connected to a source cell (eg, cell 1). In operation 1001, an SCGSA may be configured for the UE. For example, in operation 1001, the UE may receive first configuration information. The definition of the first configuration information provided in the foregoing content of embodiment 2' is applicable here.

[0216] The first network node or the second network node may determine to trigger an L3 cell handover of the UE to a target cell (eg, cell 3) based on the L3 measurement result, where cell 3 belongs to the third network node.

[0217] For example, in operation 1002 (which is an optional operation and may be performed if the second network node determines to trigger L3 switching, and may not be performed if the first network node determines to trigger L3 switching), the second network node may transmit a message indicating a change of SN (e.g., an SN change required message) to the first network node.

[0218] In operation 1003, the first network node may transmit a first message (e.g., an SN add request message) including the set of configurations to the third network node, for example, via an Xn interface. Each of the set of configurations may be associated with a respective candidate cell (e.g., a PSCell) within a set of candidate cells (e.g., a PSCell) associated with SCGSA operation.

[0219] In response to the first message, the third network node may generate a set of delta configurations, and each delta configuration within the set of delta configurations is associated with a corresponding candidate cell within the set of candidate cells and is generated based on (or on top of) the configuration associated with the corresponding candidate cell within the set of configurations.

[0220] Next, in operation 1004, the third network node may transmit a second message (e.g., an SN add request confirm message) including the set of delta configurations to the first network node, for example, via an Xn interface. For example, the set of delta configurations may include {DeltaConfig1 with assumed cell #1 as the source cell, DeltaConfig2 with assumed cell #2 as the source cell, ..., DeltaConfigN with assumed cell #N as the source cell}, where N is the number of candidate cells included in the set of candidate cells.

[0221] After operation 1003, in operation 1005, the UE may switch to the candidate cell (e.g., cell 2) based on the SCGSA configuration, for example, in response to satisfying an execution condition associated with the candidate cell. The UE may indicate the handover to cell 2 to the first network node, and the first network node is thus aware that the UE is currently connected to cell 2.

[0222] The first network node may determine a current cell (e.g., cell 2) to which the UE is connected, where cell 2 is within the set of candidate cells. Then, in operation 1006, the first network node may transmit second configuration information to the UE, which includes a delta configuration associated with cell 2 within the set of delta configurations and generated based on (or on top of) the configuration associated with cell 2. For example, the second configuration information may be included in an RRC message (e.g., an RRC reconfiguration message) with an information element "ReconfigurationWithSync" transmitted from the first network node to the UE.

[0223] After receiving the second configuration information, the UE may determine whether to apply the second configuration information to perform L3 cell handover. For example, the UE may parse the second configuration information to determine whether the second configuration information is for L3 cell handover.

[0224] In response to determining to apply the second configuration information to perform L3 cell handover, the UE may apply the second configuration information based on the first configuration information to perform L3 cell handover in operation 1007. For example, the UE may apply the delta information included in the second configuration information based on (or on top of) the configuration associated with cell 2 (the configuration associated with cell 2 may be included in the first configuration information) to perform L3 cell handover to cell 3. For example, the UE may initiate a RACH procedure for cell 3 as instructed by the delta configuration.

[0225] Thereafter, operations 1008 to 1011 may be performed. Operations 1008 to 1011 may be the same as operations 908 to 911, respectively.

[0226] Example 3'

[0227] In embodiment 3', a UE may receive first configuration information related to SCGSA operation (also referred to as an SCGSA configuration). The first configuration information may be associated with a reference configuration related to SCGSA operation and include a set of configurations related to SCGSA operation. Each of the set of configurations is associated with a corresponding candidate cell within a set of candidate cells, and each of the set of configurations may be a corresponding first delta configuration associated with the corresponding candidate cell, or may be a reference configuration.

[0228] As an example, the reference configuration may be a configuration associated with the cell to which the UE is connected when the UE receives the first configuration information. In this example, each of the set of configurations included in the first configuration information may be a corresponding first delta configuration associated with a respective candidate cell (e.g., a PSCell) within the set of candidate cells and generated based on (or on top of) the reference configuration.

[0229] As another example, the reference configuration may be a configuration that is different from the configurations of all candidate cells associated with SCGSA operation. In this example, the first configuration information may include both the reference configuration and the set of configurations, and each of the set of configurations may be a corresponding first delta configuration associated with a respective candidate cell (e.g., a PSCell) within the set of candidate cells and generated based on (or on top of) the reference configuration.

[0230] As another example, the reference configuration may be a configuration of a candidate cell associated with SCGSA operation. In this example, each of the set of configurations included in the first configuration information is associated with a corresponding candidate cell (e.g., a PSCell) within a set of candidate cells associated with SCGSA operation. The first configuration information may indicate which configuration in the set of configurations is the reference configuration. Each of the other configurations in the set of configurations may be a corresponding first delta configuration associated with the corresponding candidate cell and generated based on (or on top of) the reference configuration.

[0231] In embodiment 3', the first network node (e.g., MN) or the second network node (e.g., source SN) may determine to trigger L3 cell handover (e.g., L3 PSCell handover) of the UE based on the L3 measurement result. The first network node may determine that the target cell of the L3 cell handover is within the set of candidate cells related to the SCGSA operation.

[0232] The first network node may generate the second delta configuration on top of at least one of the reference configuration or a first delta configuration associated with the target cell within the set of configurations.

[0233] For example, if the target cell is associated with a first delta configuration, the first network node may generate a second delta configuration based on the reference configuration and the first delta configuration associated with the target cell. As another example, if the target cell is a candidate cell whose configuration is indicated as the reference configuration, the first network node may generate the second delta configuration based on the reference configuration.

[0234] Then, the first network node may transmit second configuration information including the second delta configuration to the UE. For example, the second configuration information may be included in an RRC message (eg, an RRC reconfiguration message) with an information element ReconfigurationWithSync transmitted from the first network node to the UE.

[0235] After receiving the second configuration information, the UE may determine whether to apply the second configuration information to perform L3 cell handover. For example, the UE may parse the second configuration information to determine whether the second configuration information is for L3 cell handover.

[0236] In response to determining to apply the second configuration information to perform L3 cell handover, the UE may apply the second configuration information based on the first configuration information to perform L3 cell handover. For example, the UE may apply the second delta configuration based on (or on top of) at least one of the reference configuration or the first delta configuration associated with the target cell to perform L3 cell handover to the target cell.

[0237] As an example, if the target cell is associated with a first delta configuration, the UE may apply a second delta configuration based on (or on top of) the reference configuration and the first delta configuration associated with the target cell. As an example, if the target cell is a candidate cell whose configuration is indicated as a reference configuration, the UE may apply the second delta configuration based on (or on top of) the reference configuration.

[0238] Figure 11 An example of a second differential configuration related to L3 cell handover according to some embodiments of the present application is described.

[0239] exist Figure 11 In the example, it is assumed that the UE has been configured with two candidate PSCells (e.g., cell 1 and cell 2) associated with (or used for) SCGSA operation. The first configuration information received by the UE may include a reference configuration associated with (or used for) SCGSA operation and a corresponding first differential configuration associated with cell 1 and a corresponding first differential configuration associated with cell 2 associated with SCGSA operation. The UE is currently connected to cell 1. When the MN determines to trigger an L3 cell handover of the UE to handover the UE from cell 1 to cell 2, the MN may provide a second differential configuration for the L3 cell handover to cell 2, such as Figure 11, which is shown on top of {reference configuration related to SCGSA operation + first differential configuration associated with cell 2}. In this way, signaling overhead on the F1 / Xn interface and Uu interface for L3 cell handover can be reduced. The UE applies the received second differential configuration in the form of {reference configuration related to SCGSA operation + first differential configuration associated with cell 2 + second differential configuration for L3 cell handover to cell 2} to perform L3 cell handover to cell 2.

[0240] Example 4

[0241] In embodiment 4', the UE may receive first configuration information related to SCGSA operation. For example, the first configuration information may include a configuration of a set of candidate cells (e.g., PSCell) related to SCGSA operation. As another example, the first configuration information may be associated with a reference configuration and include a set of differential configurations, and each of the set of differential configurations may be associated with a corresponding candidate cell within a set of candidate cells (e.g., PSCell) related to SCGSA operation. The reference configuration may be a configuration associated with the cell to which the UE is connected when it receives the first configuration information, or a configuration that is different from the configuration of all candidate cells related to SCGSA operation, or a configuration of candidate cells related to SCGSA operation. All definitions of the first configuration information related to SCGSA operation provided to the UE in embodiments 1' to 3' are applicable here.

[0242] The UE may also receive second configuration information related to L3 cell handover (eg, L3 PSCell handover) to a target cell.

[0243] The UE may determine whether to apply the second configuration information to perform L3 cell switching. For example, the UE may determine not to apply the second configuration information to perform L3 cell switching in at least one of the following situations:

[0244] The UE has been handed over to a cell (e.g., a PSCell) according to a conditional configuration related to SCGSA operation within a certain time period, and the cell is different from the target cell (e.g., PSCell) for L3 cell handover indicated by the second configuration information. For example, the time period may be a fixed value, such as 1000 ms, or may be a value configured by the network.

[0245] The source cell (eg, PSCell) for L3 cell handover indicated by the second configuration information is different from the cell (eg, PSCell) to which the UE is currently connected.

[0246] In some embodiments, the UE may transmit an indication to the first network node (e.g., MN) or the second network node (e.g., source SN) indicating that the second configuration information is not to be applied or that the second configuration information is to be ignored. For example, the indication may be an RRC message. For example, the indication may include a new cause value indicating an erroneous source cell.

[0247] Upon consideration, a person skilled in the art would expect that a solution similar to that described with respect to Case 2 may be applicable to situations where a candidate cell is replaced with a candidate cell group (e.g., a candidate MCG or SCG) and the (delta) configuration associated with the candidate cell is replaced with the (delta) configuration associated with the candidate cell group.

[0248] Figure 12 A simplified block diagram illustrating an exemplary apparatus 1200 for supporting coexistence of LTM / SCGSA and L3 cell handover according to some embodiments of the present application. In some embodiments, the apparatus 1200 may be or include a UE (e.g., Figure 1 In some other embodiments, the apparatus 1200 may be or include at least a portion of a first network node (eg, a CU of a BS or a MN).

[0249] refer to Figure 12 , the apparatus 1200 may include at least one transceiver 1202 and at least one processor 1206. The at least one transceiver 1202 is coupled to the at least one processor 1206.

[0250] Although elements such as transceiver 1202 and processor 1206 are illustrated in the singular in this figure, the plural form is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present application, transceiver 1202 may be divided into two devices, such as receive circuitry (or receiver) and transmit circuitry (or transmitter). In some embodiments of the present application, apparatus 1200 may further include an input device, memory, and / or other components. Transceiver 1202 and processor 1206 may be configured to perform the methods described herein (e.g., regarding Figures 2 to 11 Any of the methods described in or other methods described in the Examples of this application).

[0251] According to some embodiments of the present application, the device 1200 may be a UE, and the transceiver 1202 and the processor 1206 may be configured to execute the UE's Figures 2 to 11The processor 1206 may be configured to: receive, via a transceiver, first configuration information related to an LTM operation or an SCGSA operation; receive, via a transceiver, second configuration information related to an L3 cell handover; determine whether to apply the second configuration information to perform the L3 cell handover; and, in response to determining that the second configuration information is to be applied to perform the L3 cell handover, apply the second configuration information based on the first configuration information to perform the L3 cell handover.

[0252] According to some embodiments of the present application, the device 1200 may be a first network node, and the transceiver 1202 and the processor 1206 may be configured to execute the first network node in relation to Figures 2 to 11 For example, the processor 1206 is configured to: determine to trigger L3 cell handover of the UE; and transmit configuration information related to the L3 cell handover to the second network node or the UE via the transceiver.

[0253] In some embodiments of the present application, the device 1200 may further include at least one non-transitory computer-readable medium. In some embodiments of the present disclosure, the non-transitory computer-readable medium may store thereon computer-executable instructions that cause the processor 1206 to implement any of the methods described above. For example, when the computer-executable instructions are executed, the processor 1206 may interact with the transceiver 1202 to perform, for example, Figures 2 to 11 The operations of the described methods or other methods described in the examples of this application.

[0254] The methods according to any of the embodiments of the present application may also be implemented on a programmed processor. However, the controller, flow charts, and modules may also be implemented on a general-purpose or special-purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit components, an integrated circuit, hardware electronic or logic circuits (e.g., discrete element circuits), a programmable logic device, or the like. Generally speaking, any device on which resides a finite state machine capable of implementing the flow charts shown in the figures may be used to implement the processor functionality of the present application. For example, embodiments of the present application provide an apparatus for supporting the coexistence of LTM / SCGSA and L3 cell handover, comprising a processor and a memory. Computer-programmable instructions for implementing a method for supporting the coexistence of LTM / SCGSA and L3 cell handover are stored in the memory, and the processor is configured to execute the computer-programmable instructions to implement the method for supporting the coexistence of LTM / SCGSA and L3 cell handover. The method for supporting the coexistence of LTM / SCGSA and L3 cell handover may be any of the methods described in the present application.

[0255] Alternative embodiments preferably implement the methods according to embodiments of the present application in a non-transitory computer-readable storage medium storing computer-programmable instructions. The instructions are preferably executed by a computer-executable component that is preferably integrated with a network security system. The non-transitory computer-readable storage medium may be stored on any suitable computer-readable medium, such as RAM, ROM, flash memory, EEPROM, optical storage device (CD or DVD), hard drive, floppy disk drive, or any suitable device. The computer-executable component is preferably a processor, but the instructions may alternatively or additionally be executed by any suitable dedicated hardware device. For example, embodiments of the present application provide a non-transitory computer-readable storage medium having computer-programmable instructions stored therein. The computer-programmable instructions are configured to implement the method for supporting coexistence of LTM / SCGSA and L3 cell handover according to any embodiment of the present application.

[0256] Although the present application has been described with reference to its specific embodiments, it is apparent that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, the various components of the embodiments may be interchangeable, added, or substituted in other embodiments. Moreover, all elements of each figure are not necessary for the operation of the disclosed embodiments. For example, it will enable one of ordinary skill in the art of the disclosed embodiments to make and use the teachings of the present application by simply adopting the elements of the independent claims. Therefore, the embodiments of the present application set forth herein are intended to be illustrative and not restrictive. Various changes may be made without departing from the spirit and scope of the present application.

[0257] In the present disclosure, for example, relational terms of "first", "second" and the like can be used only to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The term "comprises, comprising" or any other variation thereof is intended to encompass non-exclusive inclusions, such that the process, method, article or device comprising a series of elements not only comprises those elements, but may also comprise other elements that are not explicitly listed or inherent to such process, method, article or device. An element beginning with "a, an" or the like does not exclude the presence of additional identical elements in the process, method, article or device comprising the element without more constraints. Moreover, the term "another" is defined as at least a second or more. As used herein, the terms "comprise", "have" and the like are defined as "comprising".

Claims

1. A user equipment (UE), comprising: transceiver; and a processor coupled to the transceiver and configured to: Receiving, via the transceiver, first configuration information related to a lower layer triggered mobility LTM operation or a secondary cell group SCG selective activation SCGSA operation; receiving, via the transceiver, second configuration information related to layer 3 L3 cell handover; determining whether to apply the second configuration information to perform the L3 cell handover; and In response to determining to apply the second configuration information to perform the L3 cell handover, the second configuration information is applied based on the first configuration information to perform the L3 cell handover.

2. The UE according to claim 1 , wherein the first configuration information is associated with a reference configuration related to the LTM operation or the SCGSA operation, the second configuration information includes a delta configuration on top of the reference configuration, and in order to apply the second configuration information based on the first configuration information to perform the L3 cell handover, the processor is configured to: The delta configuration is applied based on the reference configuration to perform the L3 cell handover regardless of which cell the UE is currently connected to.

3. The UE according to claim 1 , wherein the first configuration information includes a set of configurations related to the LTM operation or the SCGSA operation, each of the set of configurations is associated with a corresponding candidate cell within a set of candidate cells including a current cell to which the UE is connected, the second configuration information includes a delta configuration on top of a configuration associated with the current cell within the set of configurations, and in order to apply the second configuration information based on the first configuration information to perform the L3 cell handover, the processor is configured to: The delta configuration is applied based on the configuration associated with the current cell to perform the L3 cell handover.

4. The UE according to claim 1 , wherein the first configuration information is associated with a reference configuration and includes a set of configurations related to the LTM operation or the SCGSA operation, each of the set of configurations is associated with a corresponding candidate cell within a set of candidate cells including a target cell for the L3 cell handover, each of the set of configurations is a corresponding first delta configuration associated with the corresponding candidate cell or the reference configuration, the second configuration information includes a second delta configuration on top of at least one of the reference configuration or the first delta configuration associated with the target cell within the set of configurations, and in order to apply the second configuration information based on the first configuration information to perform the L3 cell handover, the processor is configured to: The second delta configuration is applied based on the at least one of the reference configuration or the first delta configuration associated with the target cell to perform the L3 cell handover to the target cell.

5. The UE according to claim 1 , wherein the first configuration information is associated with a reference configuration and includes a set of configurations related to the LTM operation, each of the set of configurations is associated with a corresponding candidate cell within a set of candidate cells, each of the set of configurations is a corresponding first delta configuration associated with the corresponding candidate cell or the reference configuration, the second configuration information is a message instructing the UE to perform the L3 cell handover to a candidate cell within the set of candidate cells, and in order to apply the second configuration information based on the first configuration information to perform the L3 cell handover, the processor is configured to: At least one of the reference configuration or a first delta configuration within the set of configurations associated with the candidate cell is applied to perform the L3 cell handover to the candidate cell. The UE according to claim 5 , wherein the second configuration information includes an identification ID of the candidate cell.

7. A UE according to claim 2, 4 or 5, wherein the reference configuration is a configuration associated with the cell to which the UE is connected when it receives the first configuration information, or a configuration that is different from the configuration of all candidate cells related to the LTM operation or the SCGSA operation, or a configuration associated with the candidate cells related to the LTM operation or the SCGSA operation.

8. The UE according to claim 1, wherein the processor is further configured to determine not to apply the second configuration information to perform the L3 cell handover in at least one of the following situations: The UE has been handed over to a cell according to an LTM command or according to a conditional configuration related to the SCGSA operation within a certain time period, and the cell is different from the target cell of the L3 cell handover indicated by the second configuration information; or The source cell for the L3 cell handover indicated by the second configuration information is different from the cell to which the UE is currently connected. 9 . The UE of claim 8 , wherein the processor is further configured to transmit an indication to a network node via the transceiver indicating that the second configuration information is not to be applied.

10. The UE according to claim 9, wherein the indication comprises a cause value indicating an erroneous source cell.

11. A first network node, comprising: transceiver; and a processor coupled to the transceiver and configured to: Determining to trigger a layer 3 L3 cell handover of a user equipment UE; and Configuration information related to the L3 cell handover is transmitted to a second network node or the UE via the transceiver.

12. The first network node of claim 11, wherein the processor is further configured to: transmitting, via the transceiver, a first message to a third network node, wherein the first message includes a reference configuration related to the LTM operation or the SCGSA operation; and receiving, via the transceiver, a second message in response to the first message from the third network node, wherein the second message includes a delta configuration atop the reference configuration; The configuration information includes the differential configuration.

13. The first network node of claim 11, wherein the processor is further configured to: transmitting, via the transceiver, one or more first messages to a third network node, wherein the one or more first messages include a set of configurations related to the LTM operation or the SCGSA operation, and each of the set of configurations is associated with a respective candidate cell within a set of candidate cells; and One or more second messages are received via the transceiver in response to the one or more first messages from the third network node, wherein the one or more second messages include a set of delta configurations, and each delta configuration within the set of delta configurations is associated with a respective candidate cell within the set of candidate cells and is generated based on a configuration within the set of configurations associated with the respective candidate cell.

14. The first network node of claim 11, wherein the processor is further configured to: determining a target cell for the L3 cell handover, wherein the target cell is within a set of candidate cells associated with the LTM operation; The configuration information is a message requesting the second network node to trigger an LTM operation to hand over the UE to the target cell.

15. A method performed by a user equipment (UE), comprising: Receiving first configuration information related to a lower layer triggered mobility LTM operation or a secondary cell group SCG selective activation SCGSA operation; receiving second configuration information related to layer 3 L3 cell handover; determining whether to apply the second configuration information to perform the L3 cell handover; and In response to determining to apply the second configuration information to perform the L3 cell handover, the second configuration information is applied based on the first configuration information to perform the L3 cell handover.

Images