Communication processing method, apparatus, chip, and storage medium

Abstract

The present application discloses a communication processing method, an apparatus, a chip, and a storage medium. The method comprises: receiving a radio resource control (RRC) reconfiguration message, the RRC reconfiguration message comprising pre-configuration information of a second primary network device or a second secondary network device; receiving a layer 1 / layer 2 triggered mobility (LTM) handover command, the LTM handover command being used for instructing to hand over from a first primary network device to the second primary network device or from a first secondary network device to the second secondary network device; determining a change in a bearer type on the basis of the RRC reconfiguration message and the LTM handover command; and executing layer 2 processing on the basis of the determined change in the bearer type. In the method of the present application, a terminal device performs layer 2 processing on the basis of the change in the bearer type, such that protocol stack reconstruction can be adaptively performed on the basis of a bearer change in an LTM process in dual connectivity, thereby facilitating implementation of the continuity of data transmission, reducing service interruption, and improving the efficiency of LTM in dual connectivity.

Description

A communication processing method, apparatus, chip, and storage medium

[0001] This application claims priority to Chinese Patent Application No. 202411598574.3, filed on November 8, 2024, entitled “A Communication Processing Method, Apparatus, Chip and Storage Medium”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a communication processing method, apparatus, chip, and storage medium. Background Technology

[0003] In wireless communication systems, when user equipment (UE) is in a service connection state and maintaining service, cell handover is required when moving from one cell to another to ensure the continuity of UE communication.

[0004] Currently, in the 5th-generation (5G) radio access network (RAN) architecture, and with base station deployments that separate centralized units (CUs) and distributed units (DUs), 5G systems consider using Layer 1 / L2-triggered mobility (LTM) to reduce handover latency and further enhance service continuity. Layer 1 includes the physical layer (PHY), and Layer 2 includes the radio link control (RLC) layer, media access control (MAC) layer, and packet data convergence protocol (PDCP) layer.

[0005] In dual-connectivity (DC) scenarios, terminal devices can communicate with multiple access network devices. For example, a terminal device can simultaneously communicate with the master cell group (MCG) on the MN (master node) and the secondary cell group (SCG) on the SN (secondary node). Currently, improving the efficiency of LTM handover in dual-connectivity scenarios is an urgent problem to be solved. Summary of the Invention

[0006] This application provides a communication processing method, apparatus, chip, and storage medium. Based on the method described in this application, protocol stack reconstruction can be performed based on bearer change adaptability, which is beneficial to achieving data transmission continuity, reducing service interruptions, and improving the efficiency of LTM under dual connectivity.

[0007] In a first aspect, this application provides a communication processing method applied to a terminal device. The method includes: receiving a Radio Resource Control (RRC) reconfiguration message, the RRC reconfiguration message including preconfiguration information of one or more second primary network devices or one or more second secondary network devices; receiving a Layer 1 / Layer 2 triggered Mobility Transaction (LTM) handover command, the LTM handover command indicating a handover from a first primary network device to one or more second primary network devices, or indicating a handover from a first secondary network device to one or more second secondary network devices; determining a change in bearer type based on the RRC reconfiguration message and the LTM handover command; and performing Layer 2 processing based on the determined change in bearer type.

[0008] Based on the method described in the first aspect, the terminal device can receive an RRC reconfiguration message including pre-configuration information of the target network device and an LTM switching command. It can determine the change of bearer type based on the RRC reconfiguration message and the LTM switching command, and perform layer 2 processing based on the change of bearer type. This is beneficial for protocol stack reconstruction based on bearer change adaptability in the dual-connectivity LTM process, which is conducive to achieving data transmission continuity, reducing service interruption, and improving the efficiency of LTM under dual connectivity.

[0009] In one possible implementation, an RRC reconfiguration message and an LTM handover command are received from a first primary network device. The RRC reconfiguration message includes pre-configuration information of one or more second primary network devices, and the LTM handover command indicates a handover from the first primary network device to one or more second primary network devices. The method further includes: receiving first indication information from the first primary network device, the first indication information indicating a processing strategy for secondary cell group (SCG) configuration in the LTM, the processing strategy including retaining or releasing the SCG configuration; and determining a change in bearer type based on the RRC reconfiguration message and the LTM handover command, including determining the change in bearer type based on the RRC reconfiguration message, the LTM handover command, and the first indication information.

[0010] Based on this implementation, the change of bearer type can be determined according to the processing policy indication information configured in SCG, without having to wait for LTM to determine whether SCG is configured to retain or release and to determine the change of growth type. This is conducive to timely L2 processing and protocol stack reconstruction, which is beneficial to achieve data transmission continuity, reduce service interruption, and improve the efficiency of LTM under dual connection.

[0011] In one possible implementation, the first indication information is carried by any of the following signaling: RRC signaling; Downlink Control Information (DCI) signaling; Physical Downlink Control Channel (PDCCH) signaling; Physical Downlink Shared Channel (PDSCH) signaling.

[0012] In one possible implementation, the first indication information instructs the LTM to retain the SCG configuration and perform Layer 2 processing, including performing Layer 2 processing corresponding to the primary cell group MCG and SCG.

[0013] Based on this implementation, the protocol stack can be adaptively rebuilt according to changes in bearer type during LTM handover, ensuring the continuity of data transmission.

[0014] In one possible implementation, the first instruction information instructs the LTM to release the SCG configuration and perform layer 2 processing, including performing layer 2 processing corresponding to the MCG.

[0015] Based on this implementation, the protocol stack can be adaptively rebuilt according to changes in bearer type during LTM handover, ensuring the continuity of data transmission.

[0016] In one possible implementation, the RRC reconfiguration message and the LTM handover command are received from the first primary network device or the first secondary network device. The RRC reconfiguration message includes preconfiguration information of one or more secondary network devices. The LTM handover command indicates a handover from the first secondary network device to one or more secondary network devices and performs Layer 2 processing, including performing Layer 2 processing corresponding to the SCG.

[0017] Based on this implementation, the protocol stack can be adaptively rebuilt according to changes in bearer type during LTM handover, ensuring the continuity of data transmission.

[0018] In one possible implementation, the pre-configuration information includes bearer type configuration, wherein the bearer class includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0019] In one possible implementation, the change of bearer type includes at least one of the following: change between MCG bearer and SCG bearer; change between MCG bearer and split bearer; change between SCG bearer and split bearer; change between primary network device MN-terminated bearer and secondary network device SN-terminated bearer.

[0020] In one possible implementation, the layer 2 processing includes at least one of the following: Media Access Control (MAC) layer reset; Radio Link Control (RLC) layer re-establishment; Packet Data Convergence Protocol (PDCP) layer re-establishment.

[0021] Secondly, this application provides a communication processing method applied to a first primary network device or a first secondary network device. The method includes: sending a Radio Resource Control (RRC) reconfiguration message to a terminal device, the RRC reconfiguration message including preconfiguration information of one or more secondary network devices or one or more secondary network devices; and sending a Layer 1 / Layer 2 Triggered Mobility (LTM) handover command to the terminal device, the LTM handover command indicating a handover from the first primary network device to one or more secondary network devices, or indicating a handover from the first secondary network device to one or more secondary network devices.

[0022] Based on the method described in the second aspect, by sending an RRC reconfiguration message including the pre-configuration information of the target network device and an LTM switching command to the terminal device, the terminal device can determine the change of bearer type based on the RRC reconfiguration message and the LTM switching command, and perform layer 2 processing based on the change of bearer type. This is beneficial for protocol stack reconstruction based on bearer change adaptability in the dual-connectivity LTM process, which helps to achieve data transmission continuity, reduce service interruption, and improve the efficiency of LTM under dual connectivity.

[0023] In one possible implementation, the pre-configuration information includes bearer type configuration, wherein the bearer class includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0024] In one possible implementation, the RRC reconfiguration message includes pre-configuration information of one or more second primary network devices, and the LTM handover command is used to indicate a handover from a first primary network device to one or more second primary network devices. The method further includes sending a first indication message to a terminal device, the first indication message being used to indicate a processing strategy for the secondary cell group (SCG) configuration in LTM, the processing strategy including retaining or releasing the SCG configuration.

[0025] Based on this implementation, the processing policy indication information configured by SCG can be used to indicate the change of bearer type to the terminal device. This eliminates the need for the terminal device to wait for LTM to determine whether the SCG configuration is to retain or release and to determine the change of growth type. This is beneficial for timely L2 processing and protocol stack reconstruction, which helps to achieve data transmission continuity, reduce service interruptions, and improve the efficiency of LTM under dual connectivity.

[0026] In one possible implementation, the first indication information is carried by any of the following signaling: RRC signaling; Downlink Control Information (DCI) signaling; Physical Downlink Control Channel (PDCCH) signaling; Physical Downlink Shared Channel (PDSCH) signaling.

[0027] In one possible implementation, the first indication information is determined based on a measurement report received from the terminal device, wherein the measurement report includes a Layer 3 measurement report and / or a Layer 1 measurement report.

[0028] Based on this implementation method, the source and host network devices can flexibly determine the processing strategy of SCG configuration, which is beneficial for flexibly configuring dual connections of terminal devices according to the communication environment.

[0029] In one possible implementation, the method further includes: sending first processing information to one of one or more second master network devices, the first processing information being used to indicate a processing policy regarding SCG configuration in LTM, the processing policy regarding SCG configuration indicated by the first processing information being the same as the processing policy regarding SCG configuration indicated by the first indication information.

[0030] Based on this implementation method, the target primary network device can be instructed on the processing strategy of SCG configuration, which is conducive to the target primary network device configuring secondary network devices in a timely manner and improving the efficiency of LTM under dual connectivity.

[0031] In one possible implementation, the first processing information is transmitted via the Xn interface.

[0032] In one possible implementation, the first indication information is determined based on an LTM handover request response received from one or more second master network devices, the LTM handover request response including an indication of the processing policy for the SCG configuration.

[0033] In one possible implementation, the method further includes sending a second indication message to one of one or more second primary network devices, the second indication message indicating the target cell for handover, the target cell being determined based on a Layer 1 measurement report received from the terminal device.

[0034] Based on this implementation, the source network device can determine the cell that the terminal device needs to switch to according to the communication environment, and indicate the target cell to the target network device. This is beneficial for the target network device to configure the secondary network device in a timely manner, and it is also beneficial to improve the efficiency of LTM under dual connectivity.

[0035] In one possible implementation, the method further includes sending a third indication message to the secondary network device (SN), the third indication message being used to indicate that the SN configuration should be updated.

[0036] Based on this implementation, the primary network device can instruct the secondary network device to update the configuration of the terminal device, which helps to improve the efficiency of LTM under dual connectivity.

[0037] In one possible implementation, the third instruction information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; a change between a primary network device MN-terminated bearer and a secondary network device SN-terminated bearer.

[0038] In one possible implementation, the method further includes sending a fourth indication message, which is used to indicate the status information of the SCG configuration after LTM.

[0039] Based on this implementation method, it is beneficial for all candidate network devices in the communication system to update the SCG-related configuration status of the terminal device, thus avoiding potential failures or errors in the subsequent LTM due to inconsistent SCG configuration status.

[0040] In one possible implementation, the RRC reconfiguration message includes pre-configuration information for one or more second auxiliary network devices, and the LTM handover command is used to indicate a handover from the first auxiliary network device to one of the one or more second auxiliary network devices. The method further includes sending a fifth indication message to the primary network device MN, the fifth indication message being used to indicate an update to the MN configuration.

[0041] Based on this implementation, the secondary network device can notify the primary network device about the terminal device's configuration update, which helps improve the efficiency of LTM under dual connectivity.

[0042] In one possible implementation, sending a Radio Resource Control (RRC) reconfiguration message to a terminal device includes: sending the RRC reconfiguration message to the terminal device via the MN.

[0043] In one possible implementation, the fifth instruction information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; a change between a primary network device MN-terminated bearer and a secondary network device SN-terminated bearer.

[0044] Thirdly, this application provides a communication processing method applied to a second primary network device. The method includes: receiving a Layer 1 / Layer 2 triggered mobility LTM handover request from a first primary network device; sending an LTM handover request response to the first primary network device, the LTM handover request response including pre-configuration information; determining a processing strategy for the secondary cell group (SCG) configuration in the LTM, the processing strategy including retaining or releasing the SCG configuration; and based on the SCG configuration processing strategy, sending an SN add request or a terminal device context release request to the secondary network device (SN).

[0045] Based on the method described in the third aspect, the target primary network device can determine the processing strategy for SCG configuration and perform timely configuration of the secondary network device according to the corresponding processing strategy, which is beneficial to improving the efficiency of LTM under dual connectivity.

[0046] In one possible implementation, the pre-configuration information includes bearer type configuration, wherein the bearer class includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0047] In one possible implementation, the method further includes: the processing policy of the SCG configuration is determined based on first processing information received from the first master network device, the first processing information being used to indicate the processing policy of the SCG configuration in the LTM.

[0048] In one possible implementation, the first processing information is transmitted via the Xn interface.

[0049] In one possible implementation, the processing policy configured by the SCG is pre-configured or determined in response to an LTM handover request received from the first primary network device. Based on the processing policy configured by the SCG, an SN add request or a terminal device context release request is sent to the secondary network device SN, including: receiving second indication information from the first primary network device, the second indication information being used to indicate the target cell for handover; and sending an SN add request or a terminal device context release request to the SN based on the processing policy configured by the SCG and the second indication information.

[0050] Based on this implementation, the target primary network device can configure the secondary network device in a timely manner, which is beneficial to improving the efficiency of LTM under dual connectivity.

[0051] In one possible implementation, the method further includes sending a third indication message to the SN, the third indication message being used to indicate that the SN configuration should be updated.

[0052] Based on this implementation, the target primary network device can instruct the secondary network device to update the configuration of the terminal device, which helps to improve the efficiency of LTM under dual connectivity.

[0053] In one possible implementation, the third instruction information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; a change between a primary network device MN-terminated bearer and a secondary network device SN-terminated bearer.

[0054] In one possible implementation, the method further includes sending a fourth indication message, which is used to indicate the status information of the SCG configuration after LTM.

[0055] Based on this implementation method, it is beneficial for all candidate network devices in the communication system to update the SCG-related configuration status of the terminal device, thus avoiding potential failures or errors in the subsequent LTM due to inconsistent SCG configuration status.

[0056] Fourthly, this application provides a communication device, which may be a terminal device, a device within a terminal device, or a device compatible with a terminal device. The communication device may also be a chip system, capable of executing the methods performed by the terminal device in the first aspect. The functions of the communication device can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more units corresponding to the aforementioned functions. These units may be software and / or hardware. The operations performed by the communication device and its beneficial effects are described in the first aspect above, and will not be repeated here.

[0057] Fifthly, this application provides a communication device, which may be a network device, a device within a network device, or a device compatible with a network device; wherein, the communication device may also be a chip system, and the communication device can execute the method performed by the network device in the second aspect. The function of the communication device can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units corresponding to the above functions. The unit may be software and / or hardware. The operation performed by the communication device and its beneficial effects can be found in the method and beneficial effects of the second aspect above, and will not be repeated here.

[0058] Sixthly, this application provides a communication device, which may be a network device, a device within a network device, or a device compatible with a network device; wherein, the communication device may also be a chip system, and the communication device can execute the method performed by the network device in the third aspect. The function of the communication device can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units corresponding to the above functions. The unit may be software and / or hardware. The operation performed by the communication device and its beneficial effects can be referred to the method and beneficial effects in the second aspect above, and will not be repeated here.

[0059] In a seventh aspect, this application provides a communication device including a processor, which, when the processor calls a computer program in memory, executes a method performed by a terminal device or network device as described in the first, second, or third aspect.

[0060] Eighthly, this application provides a communication device including a processor and a memory for storing computer execution instructions; the processor is configured to execute the computer execution instructions stored in the memory to cause the communication device to perform a method performed by a terminal device or network device as described in the first, second, or third aspects.

[0061] Ninthly, this application provides a communication device including a processor, a memory, and a transceiver. The transceiver is used to receive or transmit signals; the memory is used to store a computer program; and the processor is used to invoke the computer program from the memory to execute a method performed by a terminal device or network device, as described in the first, second, or third aspects.

[0062] In a tenth aspect, this application provides a communication device including a processor and an interface circuit, the interface circuit being configured to receive computer execution instructions and transmit them to the processor; the processor executing the computer execution instructions to perform a method performed by a terminal device or network device as described in the first, second, or third aspect.

[0063] In one aspect, this application provides a computer-readable storage medium for storing computer-executable instructions that, when executed, cause a terminal device or network device to perform a method as described in the first, second, or third aspect.

[0064] In a twelfth aspect, this application provides a communication device that includes functions or units for performing any of the methods described in the first, second, or third aspects.

[0065] In a thirteenth aspect, this application provides a computer program product including a computer program that, when executed, causes the method performed by a terminal device or network device, as described in the first, second, or third aspect, to be implemented.

[0066] In a fourteenth aspect, this application provides a communication system comprising a terminal device and a network device; wherein the terminal device is used to perform the method described in the first aspect, and the network device is used to perform the method described in the second or third aspect. Attached Figure Description

[0067] Figure 1 is a schematic diagram of the architecture of a communication system under dual connectivity provided in an embodiment of this application;

[0068] Figure 2 is a schematic diagram of the network architecture of a network device provided in an embodiment of this application;

[0069] Figure 3 is a schematic diagram of CU-DU separation of a network device provided in an embodiment of this application;

[0070] Figure 4 is a schematic diagram of the control plane architecture of a communication system supporting dual connectivity provided in an embodiment of this application;

[0071] Figure 5 is a schematic diagram of the user plane architecture of a communication system supporting dual connectivity provided in an embodiment of this application;

[0072] Figure 6 is a schematic diagram of the user plane architecture of a communication system supporting dual connectivity provided in an embodiment of this application;

[0073] Figure 7 is a schematic diagram of a dual-connectivity (DC) scenario provided in an embodiment of this application;

[0074] Figure 8 is a schematic diagram of a switching interaction provided in an embodiment of this application;

[0075] Figure 9 is an interactive schematic diagram of L1 / L2 triggered mobility (LTM) provided in an embodiment of this application;

[0076] Figure 10 is a schematic diagram of an interaction of L1 / L2 triggered mobility between DUs within a CU according to an embodiment of this application;

[0077] Figure 11 is an interactive schematic diagram of L1 / L2 triggering mobility within a CU and DU provided in an embodiment of this application;

[0078] Figure 12 is a schematic diagram of the interaction between LTMs in dual-connectivity CUs provided in an embodiment of this application;

[0079] Figure 13 is a schematic diagram of the interaction between LTMs in dual-connectivity CUs provided in an embodiment of this application;

[0080] Figure 14 is a schematic diagram of the interaction between LTMs in dual-connectivity CUs provided in an embodiment of this application;

[0081] Figure 15 is a schematic diagram of the interaction between LTMs in dual-connectivity CUs provided in an embodiment of this application;

[0082] Figure 16 is a schematic diagram of the interaction between LTMs in dual-connectivity CUs provided in an embodiment of this application;

[0083] Figure 17 is a schematic diagram of the interaction between LTMs in dual-connectivity CUs provided in an embodiment of this application;

[0084] Figure 18 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0085] Figure 19 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0086] Figure 20 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0087] Figure 21 is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0088] Figure 22 is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0089] Figure 23 is a schematic diagram of the structure of a chip provided in an embodiment of this application. Detailed Implementation

[0090] The terms "first" and "second," etc., used in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0091] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0092] In this application, "at least one (item)" refers to one or more, "more than one" refers to two or more, "at least two (items)" refers to two or three or more, and "and / or" is used to describe the correspondence between related objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0093] The terms "comprising" and "having," and any variations thereof, mentioned in the following description of the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include other steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices. It should be noted that in the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any method or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other methods or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner. To better understand the embodiments of this application, the system architecture involved in the embodiments of this application is first introduced below:

[0094] The technical solutions of this application can be applied to various communication systems, such as: Long Term Evolution (LTE) systems, LTE Frequency Division Duplex (FDD) systems, LTE Time Division Duplex (TDD) systems, Worldwide Interoperability for Microwave Access (WiMAX) or Wireless Local Area Network (WLAN) systems, New Radio (NR), the 3rd Generation Partner Project (3GPP) service-based architecture (SBA) and other fifth-generation (5G) or sixth-generation (6G) communication systems, and other communication systems that have evolved after 5G.

[0095] Figure 1 is a schematic diagram of the architecture of a communication system under dual connectivity according to an embodiment of this application. To facilitate understanding of the embodiments of this application, the communication system applicable to the embodiments of this application will be described in detail using the communication system shown in Figure 1 as an example. It should be noted that the solutions in the embodiments of this application can also be applied to other mobile communication systems, and the corresponding names can be replaced by the names of the corresponding functions in other mobile communication systems.

[0096] As shown in Figure 1, the communication system includes terminal equipment, master node (MN), secondary node (SN), and core network composed of one or more core network elements.

[0097] In this system, the terminal device can have one wireless connection each to the MN and the SN, meaning the wireless network can communicate with the terminal device using a dual-connection approach to provide high-speed data transmission. Depending on the communication standards supported by the MN and SN, dual connectivity can be implemented in various ways, as illustrated below.

[0098] EN-DC (E-UTRA-NR dual connectivity) refers to a terminal device that connects to an evolved Node B (eNB) of the LTE standard, acting as the MN, and a g node B (gNB) of the NR standard, acting as the SN. The MN is an eNB connected to a fourth-generation core network (CN), such as an evolved packet core network (EPC).

[0099] NGEN-DC (next generation E-UTRA-NR dual connectivity) involves terminal equipment connecting to an LTE-standard evolved Node B (eNB) acting as the MN and an NR-standard g node (gNode B, gNB) acting as the SN. The MN is an eNB connected to the 5th generation core network (5GC), and this MN can also be called a next-generation evolved Node B (ng-eNB).

[0100] NE-DC (NR-E-UTRA dual connectivity) refers to a terminal device connected to an NR-standard gNB (Mean Network Node) and an LTE-standard eNB (Signal Network Node). The MN is the gNB connected to the 5GC (5th Generation Control Center), and the SN is the eNB that provides data interaction between the terminal device and the 5GC; it is also known as an ng-eNB.

[0101] NR-DC (NR-NR dual connectivity) refers to a terminal device that connects to both a gNB (gNB) of the NR standard (MN) and a gNB of the NR standard (SN). The MN is a gNB connected to the 5GC.

[0102] It should be understood that dual connections can also be implemented in other ways, which are not listed one by one in the embodiments of this application.

[0103] Generally speaking, MN can also be called the main network device, and SN can also be called the auxiliary network device. This application does not limit the specific names. The network devices (including the main network device and the auxiliary network device) and terminal devices involved in the communication system in Figure 1 are described in detail below.

[0104] Network devices can provide wireless access services to terminal devices; that is, network devices are access devices that enable terminal devices to access the communication system wirelessly. Network devices can be evolved Node Bs (eNBs or eNodeBs) in LTE; or base stations, broadband network gateways (BNGs), aggregation switches, or non-3rd generation partnership project (3GPP) access devices in 5G networks, etc. This application does not specifically limit these categories. Network devices can also be referred to as access network devices, access nodes (ANs), radio access nodes (RANs), etc. For example, the base station in the embodiments of this application may include various forms of base stations, such as: macro base stations, micro base stations (also known as small stations), relay stations, access points, next-generation base stations (gNodeB, gNB), radio network controllers (RNC), node B (NB), base station controllers (BSC), base transceiver stations (BTS), home base stations (e.g., homeevolved nodeB, or home node B, HNB), base band units (BBU), transmitting and receiving points (TRP), transmitting points (TP), mobile switching centers, and devices that perform base station functions in device-to-device (D2D), vehicle-to-everything (V2X), machine-to-machine (M2M) communication, and Internet of Things (IoT) communication, etc. The embodiments of this application do not specifically limit these. Alternatively, network device 110 can also be a centralized unit (CU), a distributed unit (DU), a centralized unit control plane (CU-CP) node, or a centralized unit user plane (CU-UP) node.

[0105] It is understood that in the embodiments of this application, the device used to implement the network device function can be the network device itself, or it can be a device that supports the network device in implementing the function, such as a chip system or a combination of devices or components that can implement the network device function. This device can be installed in the network device. The embodiments of this application do not limit the specific technology or specific device form used in the network device.

[0106] Terminal devices include devices that provide voice and / or data connectivity to users. For example, a terminal device is a device with wireless transceiver capabilities that can be deployed on land, including indoors or outdoors, handheld, wearable, or vehicle-mounted; it can also be deployed on water (such as on ships); and it can be deployed in the air (such as on airplanes, balloons, and satellites). Terminal devices can be mobile phones, tablets, computers with wireless transceiver capabilities, virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals in industrial control, vehicle-mounted terminals, wireless terminals in self-driving vehicles, wireless terminals in remote medical care, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, wearable terminals, etc. The embodiments in this application do not limit the application scenarios. Terminal equipment 120 may also be referred to as terminal, user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, vehicle-mounted terminal, industrial control terminal, UE unit, UE station, mobile station, mobile terminal, remote station, remote terminal, mobile device, UE terminal, wireless communication equipment, UE agent, or UE device, etc. Terminal equipment can be fixed or mobile.

[0107] It is understood that, in the embodiments of this application, all or part of the functions of the terminal device can also be implemented through software functions running on hardware, or through virtualization functions instantiated on a platform (e.g., a cloud platform). The terminal device in this application can be a 5G terminal or a 6G terminal; this application does not limit this. In the embodiments of this application, the apparatus for implementing the functions of the terminal device can be the terminal device itself, or an apparatus capable of supporting the terminal device in implementing that function, such as a chip system or a combination of devices or components capable of implementing the functions of the terminal device, which can be installed in the terminal device.

[0108] It should be noted that Figure 1 is only a schematic diagram of the architecture of a communication system. This communication system may also include other devices, such as wireless relay devices and wireless backhaul devices, which are not shown in Figure 1. The embodiments of this application do not limit the number of various devices included in the communication system.

[0109] Figure 2 is a schematic diagram of the network architecture of a network device provided in an embodiment of this application. As shown in Figure 2, the network device can also be called an access network device, which may include a node gNB. The access network device can be connected to the core network device through the NG interface, and the nodes gNB can be connected to each other through the Xn-C interface. Among them, the gNB can adopt a CU-DU separation structure, and the CU and DU can be connected through the F1 interface.

[0110] Figure 3 is a schematic diagram of CU-DU separation in a network device according to an embodiment of this application. As shown in Figure 3, the CU includes a radio resource control (RRC) layer and a PDCP layer, and the DU includes a radio link control (RLC) layer, a medium access control (MAC) layer, and a physical layer (PHY). The core network device may include access and mobility management function (AMF) network elements and user plane function (UPF) network elements.

[0111] The gNB may also include an active antenna unit (AAU). The CU and DU implement some of the gNB's functions. For example, the CU handles non-real-time protocols and services, while the DU handles physical layer protocols and real-time services. The AAU implements some physical layer processing functions, radio frequency processing, and related functions of the active antenna. Since RRC layer information ultimately becomes PHY layer information, or is derived from PHY layer information, in this architecture, higher-layer signaling, such as RRC layer signaling, can also be considered as being sent by the DU, or by both the DU and CU. It is understood that network devices can be devices including one or more of the following: CU nodes, DU nodes, and AAU nodes. Furthermore, the CU can be classified as a network device in the radio access network (RAN) or a network device in the core network (CN); this application does not limit this classification.

[0112] Figure 4 is a schematic diagram of the control plane architecture of a communication system supporting dual connectivity according to an embodiment of this application. As shown in Figure 4, in dual connectivity, the node that directly interacts with the core network through control plane signaling (via the NG-C interface) is called MN (usually one), and the node that does not directly interact with the core network through control plane signaling is called SN (there can be one or more, but only one is shown in Figure 4). It should be understood that the SN can achieve indirect control plane signaling interaction with the core network through control plane signaling interaction with the MN, such as through the Xn-C interface; that is, the control plane signaling between the SN and the core network can be forwarded by the MN.

[0113] It should be understood that the control plane architecture diagram of the dual-connectivity communication system shown in Figure 4 is illustrated using a 5GC core network and an Xn interface between the MN and SN as an example. Optionally, the core network shown in Figure 4 can also be a 4G core network, such as the EPC in an LTE system, in which case the control plane signaling interaction between the MN and the core network can be performed through the S1-C interface. Optionally, the interface between the MN and SN can also be an X2 interface, in which case the control plane signaling interaction between the SN and MN can be performed through the X2-C interface. This application does not specifically limit the implementation method of the core network or the implementation method of the interface between the MN and SN in the embodiments.

[0114] Furthermore, control plane signaling interaction between the terminal device and the MN and SN can be performed via the Uu interface. As shown in Figure 4, in a dual-link system, both the MN and SN have radio resource control (RRC) layer entities and can generate control plane signaling, i.e., various RRC messages, such as RRC establishment / re-establishment messages, RRC configuration / reconfiguration messages, RRC release messages, and measurement request messages. The MN can directly send its generated RRC messages to the terminal device via the Uu interface. The terminal device can also directly send its generated RRC messages to the MN via the Uu interface, such as RRC establishment / re-establishment completion messages, RRC configuration / reconfiguration completion messages, and measurement reports.

[0115] Optionally, the SN can directly send RRC messages generated by the SN to the terminal device via the Uu interface. In this case, the terminal device can also directly send RRC messages generated by the terminal device to the SN via the Uu interface, such as RRC establishment / re-establishment completion messages, RRC configuration / reconfiguration completion messages, and measurement reports. Alternatively, the SN can first send the RRC messages generated by the SN to the MN via the control plane interface between the SN and the MN, such as the Xn-C interface or the X2-C interface, and then the MN sends them to the terminal device via the Uu interface. The RRC messages directly transmitted between the SN and the terminal device can be carried in, for example, a signalalling radio bearer (SRB). This application embodiment does not specifically limit the interaction method of control plane signaling between the SN and the terminal device.

[0116] Furthermore, in addition to the control plane signaling interactions described above, there are also user plane (CP) data interactions between the MN and the core network, and between the MN and the SN. Optionally, there may also be user plane data interactions between the SN and the core network. An example is given below.

[0117] For example, Figure 5 is a schematic diagram of the user plane architecture of a communication system supporting dual connectivity provided in an embodiment of this application, applicable to the dual connectivity architecture of the aforementioned EN-DC. As shown in Figure 5, both MN and SN have multiple radio link control (RLC) layer entities and media access control (MAC) layer entities, and the data radio bearer (DRB) in dual connectivity may include one or more of MCG bearer, SCG bearer, and split bearer. Specifically, an MCG bearer means that the RLC layer entity and MAC layer entity of the DRB exist only on MN; an SCG bearer means that the RLC layer entity and MAC layer entity of the DRB exist only on SN; and a split bearer means that the RLC layer entity and MAC layer entity of the DRB exist simultaneously on both MN and SN.

[0118] Furthermore, the bearers terminated by PDCP on the MN are called MN-terminated bearers. That is, downlink (DL) data arrives directly from the core network to the MN, and after being processed by the PDCP layer entity of the MN, it is then processed by the RLC layer entity and MAC layer entity of the MN and / or SN before being sent to the terminal device. Correspondingly, uplink (UL) data arrives from the terminal device to the MN and / or SN, and after being processed by the PDCP layer entity of the MN, it is sent to the core network.

[0119] Similarly, for PDCP termination on the SN, it is called SN terminated bearer, that is, downlink data arrives directly from the core network to the SN, and after being processed by the PDCP layer entity of the SN, it is then processed by the RLC layer entity and MAC layer entity of the MN and / or the SN before being sent to the terminal device; correspondingly, uplink data arrives from the terminal device to the MN and / or the SN, and after being processed by the PDCP layer entity of the SN, it is sent to the core network.

[0120] For example, Figure 6 is a schematic diagram of the user plane architecture of a communication system supporting dual connectivity provided in an embodiment of this application. It is applicable to the dual connectivity architectures of NGEN-DC, NE-DC, and NR-DC, i.e., a dual connectivity architecture with a core network of 5GC. As shown in Figure 6, in addition to the protocol layer entities also involved in Figure 5, MN and SN also include a service data adaptation protocol (SDAP) layer entity. The SDAP layer entity is used to map the quality of service (QoS) flow of the core network onto the aforementioned DRBs and send it to the terminal device when MN or SN interacts with the core network, or to map the data carried by the aforementioned DRBs onto QoS flows and send it to the core network. Regarding the mapping between QoS flows and DRBs, existing implementations can be referred to, and this embodiment of the application will not elaborate further.

[0121] Furthermore, for a terminal device in a dual-connectivity setup, the user plane of the SN may be connected to the core network of the MN connection, meaning that the core network can exchange data with the terminal device through the SN.

[0122] Figure 7 is a schematic diagram of a dual-connectivity (DC) scenario provided in an embodiment of this application. Dual-connectivity or multi-radio dual connectivity (MR-DC) refers to a terminal device being able to communicate with two network devices simultaneously. One network device can be an NR network device, and the other an LTE network device, or both can be NR network devices. One network device is designated as MN, and the other as SN.

[0123] As shown in Figure 7, when dual connectivity is combined with carrier aggregation (CA), each network device can include a cell group (CG). The cell group under MN is the master cell group (MCG), and the cell group under SN is the secondary cell group (SCG). The master cell group can include one primary cell (PCell) and at least one secondary cell (SCell), and the secondary cell group can include one primary secondary cell (PSCell) and at least one secondary cell (SCell).

[0124] It should be understood that when dual connectivity is not combined with CA, there is only one primary cell under MN and only one primary and secondary cell under SN. This scenario also applies to the embodiments of this application.

[0125] It should be understood that, for ease of description, Figure 7 is illustrated using the example of each cell group containing 2 SCells.

[0126] This application's embodiments can be applied to downlink signal transmission, uplink signal transmission, and sidelink communication (such as device-to-device (D2D) signal transmission). For downlink signal transmission, the transmitting device is a network device, and the corresponding receiving device is a terminal device. For uplink signal transmission, the transmitting device is a terminal device, and the corresponding receiving device is a network device. For D2D signal transmission, both the transmitting and receiving devices are terminal devices. The direction of signal transmission is not limited in this application's embodiments.

[0127] Network devices and terminal devices can communicate using licensed spectrum, unlicensed spectrum, or both simultaneously. They can also communicate using spectrum below 6 gigahertz (GHz), spectrum above 6 GHz, or both simultaneously. The embodiments of this application do not limit the spectrum resources used between network devices and terminal devices.

[0128] In the embodiments of this application, the time-domain symbol can be an orthogonal frequency division multiplexing (OFDM) symbol or a discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbol. Unless otherwise specified, the symbols in the embodiments of this application refer to time-domain symbols.

[0129] It is understood that in the embodiments of this application, the physical downlink share channel (PDSCH), physical downlink control channel (PDCCH), and physical uplink share channel (PUSCH) are only examples of downlink data channel, downlink control channel, and uplink data channel, respectively. In different systems and different scenarios, the data channel and control channel may have different names, and the embodiments of this application do not limit this.

[0130] The following are definitions of technical terms that may appear in the embodiments of this application. The terminology used in the implementation section of this application is only used to explain specific embodiments of this application and is not intended to limit this application.

[0131] (1) Cell, Source Cell, Target Cell, Candidate Cell

[0132] Network devices can be configured, deployed, or controlled at least one cell.

[0133] In a handover scenario, the cell that the terminal device accesses before the handover is called the source cell, and the cell that the terminal device accesses after the handover is called the target cell. The source cell and the target cell may be cells configured by the same network device, or they may be cells configured by different network devices.

[0134] For example, the network device is a base station. One example is that the source cell is cell 11 configured on base station 1, and the target cell is cell 12 configured on base station 1. Another example is that the source cell is cell 11 configured on base station 1, and the target cell is cell 21 configured on base station 2.

[0135] For example, in a CU-DU separated architecture, network devices include CUs and DUs. One example is that the source cell is cell 11 configured with DU1, and the target cell is cell 12 configured with DU1. Another example is that the source cell is cell 11 configured with DU1, and the target cell is cell 21 configured with DU2. DU1 and DU2 may belong to the same CU, or they may belong to different CUs.

[0136] In another example, the terminal can perform changes to the PSCell. In this example, the primary cell under the primary base station can remain unchanged. One example is that the source cell is cell 11 configured by secondary base station 1, and the target cell is cell 12 configured by secondary base station 1. Another example is that the source cell is cell 11 configured by secondary base station 1, and the target cell is cell 21 configured by secondary base station 2.

[0137] Candidate cells are also called handover candidate cells, target candidate cells, or candidate target cells; the names are not limited in this application embodiment. In some handover methods, such as the L1 / L2-triggered mobility (LTM) process described later, the network device can configure at least one candidate cell for the terminal device. In these handover methods, the target cell is one of the at least one candidate cell.

[0138] (2) Source network device, target network device, candidate network device

[0139] In a handover scenario, the network device that the terminal device communicates with before the handover is called the source network device, and the network device that the terminal device communicates with after the handover is called the target network device.

[0140] The source network device and the target network device can be the same or different.

[0141] When the source network device and the target network device are the same, it is called a handover within the network device.

[0142] For example, if the network device is a base station, and both the source and target network devices are base station 1, the source cell is cell 11 configured by base station 1, and the target cell is cell 12 configured by base station 1, then this handover is an intra-base station handover.

[0143] For example, network devices include CU and DU. Both the source network device and the target network device are DU1, the source cell is cell 11 configured in DU1, and the target cell is cell 12 configured in DU1. This handover is an intra-DU handover.

[0144] For example, if the network device is a secondary base station, and both the source and target network devices are secondary base station 1, the source cell is cell 11 configured by secondary base station 1, and the target cell is cell 12 configured by secondary base station 1, then this handover is an intra-base station handover.

[0145] When the source network device and the target network device are different, it is called a handover between network devices or a handover between different network devices.

[0146] For example, if the network device is a base station, the source cell is cell 11 configured by base station 1, the source network device is base station 1, the target cell is cell 21 configured by base station 2, and the target network device is base station 2, then this handover is an inter-base station handover.

[0147] For example, network devices include CUs and DUs. The source cell is cell 11 configured with DU1, the source network device is DU1, and the destination cell is cell 21 configured with DU2, the destination network device is DU2. This handover is an inter-DU handover. DU1 and DU2 may belong to the same CU or different CUs.

[0148] For example, if the network device is a secondary base station, the source cell is cell 11 configured by secondary base station 1, the source network device is secondary base station 1, the target cell is cell 21 configured by secondary base station 2, and the target network device is secondary base station 2, then this handover is an inter-secondary base station handover.

[0149] In some handover methods, such as L1 / L2 triggered mobility as described later, the network device communicates with at least one candidate network device to negotiate at least one candidate cell to be configured for the terminal device. In these handover methods, the target network device is one of the at least one candidate network device.

[0150] (3) Switching

[0151] In wireless communication systems, when a terminal device moves from one cell to another, or due to network issues, traffic load adjustments, equipment failures, or other reasons, the terminal device may leave the source cell and connect to the target cell to ensure the continuity of communication between the terminal device and the network. This process is called "handover".

[0152] One possible implementation is that the switching can be controlled through layer 3, i.e., the RRC layer. Please refer to Figure 8, which is a schematic diagram of a switching interaction provided in an embodiment of this application. As shown in Figure 8, the switching process can be as follows:

[0153] 801. The source base station performs measurement configuration on the terminal equipment, and the terminal equipment performs measurement according to the measurement configuration and reports the measurement report.

[0154] 802. The source base station makes a handover decision. The source base station may refer to the measurement results reported by the terminal device and / or its own handover algorithm when making the handover decision. For example, if the signal quality of the source cell is poor, but the signal quality of the target cell is good, the source base station will decide to perform the handover.

[0155] 803. The source base station sends a handover request message to the target base station. This request message transmits necessary information for handover preparation, including at least the target cell identifier, key, terminal identifier in the source cell, and basic access layer configuration.

[0156] 804. The target base station performs admission control.

[0157] 805. The target base station sends a handover request response message to the source base station. If the target base station confirms that the terminal device can access the network, it replies with a handover request response message to the source cell. The handover command sent to the terminal device can be included in the confirmation message as an RRC container.

[0158] 806. The source base station sends an RRC reconfiguration message (or handover command) to the terminal device. This message contains information required for accessing the target cell, including at least the target cell identifier, the new terminal device identifier, the target cell's security algorithm identifier, and possibly dedicated RACH resources for accessing the target cell.

[0159] 807. After receiving the handover command, the terminal device performs synchronization with the target cell, for example, through the Random Access Procedure (RACH).

[0160] 808. The terminal device sends an RRC reconfiguration complete message to the target base station. This message confirms successful RRC reconfiguration. The RRC reconfiguration complete message includes the information required by the target base station to configure the terminal device after its access, helping the target base station to better configure the terminal device's resources or measurements.

[0161] (4) L1 / L2 Triggered Mobility (LTM)

[0162] One possible implementation is that the handover can be accomplished through L1 / L2 triggered mobility. L1 / L2 triggered mobility can also be referred to as L1 / L2 handover, L1 / L2 mobility, lower layer handover, lower layer mobility, or L2 triggered mobility, etc. The embodiments of this application do not limit the names.

[0163] For scenarios with large data volumes (such as extended reality (XR) services) or frequent handovers (such as frequency range 2 (FR2)), Layer 1 / Layer 2 triggered mobility has been proposed to reduce handover latency and downtime, and improve the user experience of terminals. L1 / L2 triggered mobility instructs the terminal to perform a handover through L1 signaling or L2 signaling. L1 signaling can be downlink control information (DCI), and L2 signaling can be a Media Access Control control element (MAC CE).

[0164] The main idea behind L1 / L2 triggered mobility is as follows: The network device selects one or more candidate cell configurations based on the measurement report reported by the terminal device. This measurement report can be a Layer 3 (L3) measurement report. The network device provides the terminal device with configuration information for one or more candidate cells through pre-configuration information (which can be included in the RRC reconfiguration message). Upon receiving the L1 / L2 triggered mobility configuration information, the terminal device does not immediately perform a handover. The source network device determines whether to trigger L1 / L2 triggered mobility based on the measurement report reported by the terminal device (e.g., an L1 measurement report). The source network device sends an L1 / L2 triggered mobility cell switch command to the terminal device via L1 / L2 signaling. This command indicates the target cell identifier or target cell configuration for the handover, and optionally may also include the target beam information of the target cell. The L1 / L2 triggered mobility cell switch command can also be called an L1 / L2 handover command, or an L1 / L2 triggered mobility command, or an L1 / L2 triggered mobility MAC CE / DCI. The terminal device performs the handover process based on the instructions in the cell switch command.

[0165] Figure 9 is a schematic diagram of an L1 / L2 triggered mobility (LTM) interaction provided in an embodiment of this application. As shown in Figure 9, the LTM process can be as follows:

[0166] 901. The terminal device can perform measurement reporting based on the configured candidate cells. This measurement reporting can include any type of measurement reporting, such as Layer 1 measurement reporting, Layer 2 measurement reporting, or Layer 3 measurement reporting. This application does not impose excessive limitations on the method of performing measurement reporting.

[0167] Candidate cells can refer to all neighboring cells that the terminal device can access. The source cell receives the measurement reports sent by the terminal device and decides to perform LTM cell change.

[0168] 902. During the LTM handover preparation process, the source cell may send an LTM handover request to the target cell and potential target cells among the candidate cells. The target cell and potential target cells may respond to the source cell's LTM handover request. The source cell receives the LTM handover request response.

[0169] 903. The source cell can also send the configuration information of the target cell and potential target cells to the terminal device via RRC reconfiguration messages.

[0170] 904. After receiving the configuration information of the candidate cells, the terminal device can perform downlink synchronization and uplink synchronization for each candidate cell respectively.

[0171] 905. Source Cell: Reports L1 / L2 measurements for source cells and candidate cells to determine the target cell.

[0172] 906. The source cell issues an LTM handover command to the terminal device. This LTM handover command can be carried in MAC CE signaling. The MAC CE can contain at least the following information: Timing Advance (TA), Transmission Configuration Indication state (TCI state) identifier (IdentityDocument, ID), CFRA resource information, and candidate cell configuration information identifier.

[0173] 907. When a terminal device receives a MAC CE, it can disconnect from the source cell, execute a random access procedure, connect to the target cell, and perform data transmission through the target cell.

[0174] 908. LTM cell handover confirmed.

[0175] In some implementations, the network devices of the source cell and the target cell can be the same device, or the source cell and the target cell can be co-located.

[0176] In some implementations, the network devices of the source cell and the target cell can be different devices, or the source cell and the target cell can be non-co-located.

[0177] The handover message and the aforementioned RRC message indicating the handover are described from different perspectives. The handover message is described from a functional perspective, aiming to indicate that the message is used to instruct the terminal device to perform a handover. The RRC message is described from a message type perspective, aiming to indicate that the message is higher-layer signaling. The RRC reconfiguration message is an enumeration of RRC messages. In other words, this handover message is sent to the terminal device via higher-layer signaling.

[0178] The above examples illustrate different RRC messages, such as the RRC connection reconfiguration message in LTE and the RRC reconfiguration message in NR. These messages are merely illustrative examples for ease of understanding and should not be construed as limiting this application. This application does not limit the specific names of the handover messages used to instruct the terminal device to send the handover procedure.

[0179] When the network equipment of the source cell and the network equipment of the target cell are the same device, L1 / L2 triggered mobility can be restricted to the same CU. In this case, there are several technical solutions for implementing L1 / L2 triggered mobility, some of which are exemplified below:

[0180] Option 1: L1 / L2 triggered mobility between intra-CU and inter-DU.

[0181] Please refer to Figure 10, which is a schematic diagram of the interaction of L1 / L2 triggered mobility between DUs within a CU according to an embodiment of this application. As shown in Figure 10, the process of L1 / L2 triggered mobility between DUs within a CU includes:

[0182] 1001. The terminal device performs the measurement according to the measurement configuration and reports the measurement report.

[0183] The measurement configuration and report can be, for example, an L3 measurement configuration and report, which can be configured by the CU.

[0184] 1002. The base station (e.g., CU) determines the L1 / L2 triggered mobility configuration decision (or handover preparation decision). The base station determines to perform L1 / L2 triggered mobility and identifies multiple candidate DUs.

[0185] 1003.CU sends an LTM handover request to one or more candidate DUs. The one or more candidate DUs can be DUs belonging to one or more candidate cells.

[0186] 1004. The candidate DU sends a terminal device LTM handover request response to the CU. It also determines the candidate cells for L1 / L2 mobility triggering. The base station's configuration decision or candidate cell can refer to the terminal device's reported results and / or its own handover algorithm.

[0187] If the candidate DU confirms that the terminal device can connect, it replies to the CU with an LTM handover request response, which may include the configuration information of the candidate cell.

[0188] 1005.CU sends an RRC reconfiguration message to the source DU, which contains L1 / L2 triggered mobility preconfiguration information. The L1 / L2 triggered mobility preconfiguration information contains the configuration information of one or more candidate cells.

[0189] 1006. The source DU sends an RRC reconfiguration message to the terminal device.

[0190] Optionally, the source DU can send the RRC reconfiguration message received from the CU to the terminal device.

[0191] Optionally, the RRC reconfiguration message sent by the source DU to the terminal device may also include the configuration information of the source cell.

[0192] The configuration information for each candidate cell can be sent in one of the following ways:

[0193] a) The configuration information of each candidate cell is contained in one RRC reconfiguration message. That is, in 1005, the RRC reconfiguration message sent by the base station to the terminal device contains one or more RRC reconfiguration messages, each containing the configuration information of one or more candidate cells;

[0194] b) The configuration information for each candidate cell is contained in an Information Element (IE). That is, the RRC reconfiguration message sent by the base station to the terminal device in step 1005 contains one or more IEs, each containing the configuration information for one or more candidate cells. For example, this IE could be a CellGroupConfig IE.

[0195] In some embodiments, the RRC reconfiguration message can be sent directly from the CU to the terminal device. That is, the CU does not send the RRC reconfiguration message to the terminal device via the source DU, but sends the RRC reconfiguration message directly to the terminal device.

[0196] 1007. After receiving the RRC reconfiguration message, the terminal device sends an RRC reconfiguration complete message to the source DU. This RRC reconfiguration complete message is used to confirm the RRC reconfiguration message sent by the source DU in 1006.

[0197] 1008. The source DU sends an RRC reconfiguration complete message to the CU so that the CU can confirm that the terminal device has received the RRC reconfiguration message.

[0198] In some embodiments, the RRC reconfiguration complete message can be sent directly from the terminal device to the CU. That is, the terminal device does not send the RRC reconfiguration complete message to the CU via the source DU, but sends the RRC reconfiguration complete message directly to the CU.

[0199] 1009. The terminal device performs L1 measurement based on the L1 measurement configuration and sends an L1 measurement report. The L1 measurement configuration can be included in the RRC reconfiguration message in 1005.

[0200] 1010. The base station (e.g., the source DU) determines the triggering of L1 / L2 mobility based on the L1 measurement report sent by the terminal equipment.

[0201] 1011. The base station (e.g., the source DU) sends an L1 / L2 triggered mobility cell change command, also known as an LTM handover command, to the terminal device. This cell change command can be carried on the MAC CE or DCI. The command indicates the target cell identifier for the terminal device's handover, or indicates the target cell configuration identifier. The target cell is included in the aforementioned candidate cells.

[0202] 1012. Terminal device accesses target cell. The terminal device can perform synchronization with the base station (e.g., target DU) to which the target cell belongs. This synchronization process can be achieved through the RACH procedure or through other procedures (e.g., RACH-less).

[0203] 1013. Confirm LTM handover completion. The terminal device can confirm the completion of LTM handover by sending an RRC reconfiguration completion message to the base station (e.g., the target DU).

[0204] In some embodiments, the RRC reconfiguration complete message may be sent by the terminal device to the CU via the target DU. That is, the terminal device first sends the RRC reconfiguration complete message to the target DU, and then the target DU sends the RRC reconfiguration complete message to the CU.

[0205] Option 2: L1 / L2 trigger mobility within CU and intra-DU.

[0206] Please refer to Figure 11, which is an interactive schematic diagram of L1 / L2-triggered mobility within a CU and DU according to an embodiment of this application. As shown in Figure 11, the process of triggering mobility within a CU and DU using L1 / L2 includes:

[0207] 1101. The terminal device performs measurements according to the measurement configuration and reports the measurement; the measurement configuration and report can be an L3 measurement configuration and report, which can be configured by the CU.

[0208] 1102. The base station (e.g., CU) determines the L1 / L2 triggered mobility configuration decision (or handover preparation decision). The base station determines whether to perform L1 / L2 triggered mobility and identifies candidate cells for L1 / L2 triggered mobility. The base station may refer to the reported results from the terminal equipment and / or its own handover algorithm when determining the configuration decision or candidate cells.

[0209] 1103.CU sends an RRC reconfiguration message to DU, which includes L1 / L2 triggered mobility preconfiguration information. The L1 / L2 triggered mobility preconfiguration information contains configuration information for one or more candidate cells.

[0210] 1104.DU sends an RRC reconfiguration message to the terminal device.

[0211] Optionally, the DU can send the RRC reconfiguration message received from the CU to the terminal device.

[0212] Optionally, the RRC reconfiguration message sent by the DU to the terminal device may also include the configuration information of the source cell.

[0213] The configuration information for each candidate cell can be sent in one of the following ways:

[0214] a) The configuration information of each candidate cell is contained in one RRC reconfiguration message. That is, the RRC reconfiguration message sent by the base station to the terminal device in 1105 contains one or more RRC reconfiguration messages, each containing the configuration information of one or more candidate cells;

[0215] b) The configuration information for each candidate cell is contained in an IE. That is, the RRC reconfiguration message sent by the base station to the terminal device in step 1105 contains one or more IEs, each containing the configuration information for one or more candidate cells. For example, this IE can configure a cell group.

[0216] In some embodiments, the RRC reconfiguration message can be sent directly from the CU to the terminal device. That is, the CU does not send the RRC reconfiguration message to the terminal device via the DU, but sends the RRC reconfiguration message directly to the terminal device.

[0217] 1105. After receiving the RRC reconfiguration message, the terminal device sends an RRC reconfiguration completion message to the DU. This RRC reconfiguration completion message is used to confirm the RRC reconfiguration message sent by the base station in 1105.

[0218] 1006.DU sends an RRC reconfiguration complete message to CU so that CU can confirm that the terminal device has received the RRC reconfiguration message.

[0219] In some embodiments, the RRC reconfiguration complete message can be sent directly from the terminal device to the CU. That is, the terminal device does not send the RRC reconfiguration complete message to the CU via the DU, but sends the RRC reconfiguration complete message directly to the CU.

[0220] 1107. The terminal device performs L1 measurement based on the L1 measurement configuration and sends an L1 measurement report. The L1 measurement configuration can be included in the RRC reconfiguration message in 1105.

[0221] 1108. The base station (e.g., DU) determines the triggering of L1 / L2 mobility based on the L1 measurement report sent by the terminal equipment.

[0222] 1109. The base station (e.g., DU) sends an L1 / L2 triggered mobility cell change command, also known as an LTM handover command, to the terminal device. This cell change command can be carried on the MAC CE or DCI. The cell change command indicates the target cell identifier for the terminal device's handover, or indicates the target cell configuration identifier for the terminal device's handover. The target cell is included in the aforementioned candidate cells.

[0223] 1110. Terminal device accesses target cell. The terminal device can perform synchronization with the base station (e.g., DU). This synchronization process can be achieved through the RACH procedure or through other procedures (e.g., RACH-less).

[0224] 1111. Confirm LTM handover completion. The terminal device can confirm the completion of LTM handover by sending an RRC reconfiguration completion message to the base station (e.g., DU).

[0225] In some embodiments, the RRC reconfiguration complete message may be sent from the terminal device to the CU via the DU. That is, the terminal device first sends the RRC reconfiguration complete message to the DU, and then the DU sends the RRC reconfiguration complete message to the CU.

[0226] The network equipment of the source cell and the network equipment of the target cell can be different devices, meaning that L1 / L2 triggered mobility can occur between different CUs. In dual connectivity, when L1 / L2 triggered mobility occurs between CUs, due to changes in the base station and bearer, both the network side and the terminal side in LTM will involve resource configuration and protocol stack processing.

[0227] In a dual-connectivity scenario, L1 / L2 triggered mobility (LTM) between CUs can typically include two scenarios: Scenario 1 is LTM between MNs; Scenario 2 is LTM between SNs.

[0228] This application further proposes a communication method to ensure the stability and continuity of LTM between CUs under dual connectivity, and to improve the efficiency of LTM.

[0229] Scenario 1: LTM between MNs

[0230] Referring to Figure 12, Figure 12 is a schematic diagram of the interaction between CUs under dual connectivity according to an embodiment of this application. As shown in Figure 12, the LTM process between MNs may include:

[0231] 1201. The terminal device reports the measurement to the source MN.

[0232] The terminal device can perform measurements according to the measurement configuration and report the measurement; the measurement configuration and report can be an L3 measurement configuration and report, and can be configured by the source MN.

[0233] 1202. The source MN sends an LTM handover request to one or more candidate MNs (including the target MN).

[0234] The source MN can refer to the reported results of the terminal device and / or its own handover algorithm to determine one or more candidate MNs of LTM. The target MN for subsequent handover can be included in the determined one or more candidate MNs. The one or more candidate MNs can be the MNs to which one or more candidate PCells belong.

[0235] 1203. The candidate MN sends an LTM switching request response to the source MN.

[0236] Candidate MNs can be pre-configured with LTM pre-configuration information for candidate MNs / candidate PCells, and the LTM handover request response can include this LTM pre-configuration information. The LTM pre-configuration information can include configuration information related to measurement reporting, cell identifier, handover conditions, etc., and can also be configured with configuration information to instruct the terminal on Layer 2 processing after handover, wherein Layer 2 processing can include MAC layer reset, RLC layer re-establishment, and PDCP layer re-establishment.

[0237] 1204. The source MN sends an RRC reconfiguration message to the terminal device.

[0238] The RRC reconfiguration message may include LTM pre-configuration information received from candidate MNs. The LTM pre-configuration information contains configuration information for one or more candidate MNs.

[0239] In some embodiments, the RRC reconfiguration message includes bearer type configurations for one or more candidate MNs.

[0240] In some embodiments, the bearer type includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0241] Optionally, the RRC reconfiguration message may also include configuration information of the source MN, which may include the bearer type configuration of the source MN.

[0242] In some embodiments, the configuration information of each candidate MN can be included in an RRC reconfiguration message. That is, the RRC reconfiguration message sent by the source MN to the terminal device in 1204 contains one or more RRC reconfiguration messages, each containing the configuration information of one or more candidate MNs.

[0243] In some embodiments, the configuration information of each candidate MN can be contained in an IE. That is, the RRC reconfiguration message sent by the source MN to the terminal device in 1204 contains one or more IEs, each containing the configuration information of one or more candidate MNs.

[0244] 1205. After receiving the RRC reconfiguration message, the terminal device sends an RRC reconfiguration complete message to the source MN. This RRC reconfiguration complete message is used to confirm the RRC reconfiguration message sent by the source MN in 1204.

[0245] 1206. The terminal device reports L1 measurements to the source MN.

[0246] The terminal device can perform L1 measurements and send L1 measurement reports based on the L1 measurement configuration. The L1 measurement configuration can be included in the RRC reconfiguration message in 1204.

[0247] 1207. The source MN sends an LTM switching command to the terminal device.

[0248] LTM switching commands can be used to indicate a switch from the source MN to one of one or more candidate MNs, i.e., the target MN.

[0249] The LTM handover command can be carried on the MAC CE or DCI. The LTM handover command indicates the target cell identifier for the terminal device's handover, or the target cell configuration identifier. The candidate MNs include the MN to which the target cell belongs, i.e., the target MN.

[0250] In some embodiments, the target MN may be determined by the source MN based on a measurement report received from the terminal device, wherein the measurement report may include, for example, the L3 measurement report in 1201 and / or the L1 measurement report in 1206.

[0251] 1208. The source MN sends the first instruction information to the terminal device.

[0252] The first indication information is used to indicate the processing strategy for SCG configuration in LTM, which includes retaining or releasing the SCG configuration.

[0253] In the LTM between MNs, the source MN can indicate to the terminal device, through the first indication information, whether the processing of the SCG configuration is to be retained or released, so that the terminal device can determine the change of bearer type after switching from the source MN to the target MN based on the RRC reconfiguration message, the LTM switching command, and the first indication information.

[0254] In some embodiments, the first indication information may be a dedicated signaling sent separately as shown in 1208.

[0255] In some embodiments, the first indication information may be carried by the LTM switching command in 1207, that is, 1207 and 1208 may be a single step.

[0256] In some embodiments, the first indication information may be included in, for example, LTM pre-configuration information in 1203 and 1204, and carried by an RRC message, such as an RRC reconfiguration message.

[0257] In some embodiments, the first indication information may be carried by DCI signaling.

[0258] In some embodiments, the first indication information may be carried by PDCCH signaling.

[0259] In some embodiments, the first indication information may be carried by PDSCH signaling.

[0260] In some embodiments, the first indication information may be determined by the source MN based on a measurement report received from the terminal device, wherein the measurement report may include the L3 measurement report in 1201 and / or the L1 measurement report in 1206.

[0261] In some embodiments, the first indication information may be determined by the source MN based on LTM handover request responses received from one or more candidate MNs, the LTM handover request responses including indications of the processing policy configured for the SCG.

[0262] 1209. The source MN sends the first processing information to the target MN, indicating the processing strategy configured by the SCG to the target MN.

[0263] The first processing information is used to indicate the processing strategy for the SCG configuration in the LTM, which includes retaining or releasing the SCG configuration. Furthermore, the processing strategy for the SCG configuration indicated by the first processing information is the same as the processing strategy for the SCG configuration indicated by the first indication information in 1208.

[0264] In some embodiments, the first processing information may be transmitted via the Xn interface.

[0265] 1210. The target MN sends an SN add request or a terminal device context release request to the SN based on the processing strategy configured in the SCG.

[0266] The target MN can determine the processing strategy for the SCG configuration in the LTM based on the first processing information received.

[0267] In some embodiments, the first processing information indicates that the SCG configuration should be released, and the target MN may send a terminal device context release request or an SCG configuration information release indication to the SN.

[0268] In some embodiments, the first processing information indicates that the SCG configuration is retained, and the target MN can perform the SN addition process, that is, send an SN addition request to the SN and receive an SN addition request response from the SN, thereby realizing the addition of the SN.

[0269] In some embodiments, if the first indication information indicates that the SCG configuration is released, the source MN may also directly send the first processing information to the SN, indicating that the SCG configuration is released and that the terminal device context is released to the SN.

[0270] 1211. The terminal device determines the change in bearer type and performs L2 processing.

[0271] The terminal device can determine the change in bearer type after switching from the source MN to the target MN based on the RRC reconfiguration message and LTM handover command received from the source MN, and perform L2 processing accordingly.

[0272] In some embodiments, a change in bearer type may include at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer.

[0273] In some embodiments, L2 processing may include at least one of the following: MAC layer reset; RLC layer re-establishment; PDCP layer re-establishment.

[0274] In some embodiments, if the terminal device also receives first indication information for indicating the processing strategy for SCG configuration in LTM, the terminal device can determine the change in bearer type after switching from source MN to target MN based on the RRC reconfiguration message, LTM switching command and the first indication information, and perform L2 processing.

[0275] In some embodiments, the first indication information indicates that the SCG configuration is retained in the LTM. The terminal device can determine the change in the bearer type corresponding to the MCG in the MN and the SCG in the SN after switching from the source MN to the target MN, and perform L2 processing, including: performing layer 2 processing corresponding to the MCG and SCG.

[0276] In some embodiments, the first indication information indicates that the SCG configuration in the LTM is released. The terminal device can determine that the SCG configuration is no longer retained after switching from the source MN to the target MN. Therefore, it only needs to determine the change of the bearer type corresponding to the MCG in the MN and perform L2 processing, including: performing the layer 2 processing corresponding to the MCG.

[0277] In some embodiments, the source MN or the target MN may send a third indication message to the SN, which is used to indicate that the SN configuration should be updated.

[0278] In some embodiments, the third indication information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer. Based on this, the SN can be aware of the change in bearer type in the LTM.

[0279] In some embodiments, the source MN or the target MN may send a fourth indication message, which is used to indicate the status information of the SCG configuration after LTM. For example, the source MN or the target MN notifies other candidate MNs that the SCG configuration information has been released or is in a reserved state, so that the candidate MNs update the status of the SCG-related configuration of the terminal device.

[0280] Referring to Figure 13, Figure 13 is a schematic diagram of the interaction between CUs under dual connectivity according to an embodiment of this application. As shown in Figure 13, the LTM process between MNs may include:

[0281] 1301. The terminal device reports the measurement to the source MN.

[0282] The terminal device can perform measurements according to the measurement configuration and report the measurement; the measurement configuration and report can be an L3 measurement configuration and report, and can be configured by the source MN.

[0283] 1302. The source MN sends an LTM handover request to one or more candidate MNs (including the target MN).

[0284] The source MN can refer to the reported results of the terminal device and / or its own handover algorithm to determine one or more candidate MNs of LTM. The target MN for subsequent handover can be included in the determined one or more candidate MNs. The one or more candidate MNs can be the MNs to which one or more candidate PCells belong.

[0285] 1303. The candidate MN sends an LTM switching request response to the source MN.

[0286] Candidate MNs can be pre-configured with LTM pre-configuration information for candidate MNs / candidate PCells, and the LTM handover request response can include this LTM pre-configuration information. The LTM pre-configuration information can include configuration information related to measurement reporting, cell identifier, handover conditions, etc., and can also be configured with configuration information to instruct the terminal on Layer 2 processing after handover, wherein Layer 2 processing can include MAC layer reset, RLC layer re-establishment, and PDCP layer re-establishment.

[0287] 1304. The source MN sends an RRC reconfiguration message to the terminal device.

[0288] The RRC reconfiguration message may include LTM pre-configuration information received from candidate MNs. The LTM pre-configuration information contains configuration information for one or more candidate MNs.

[0289] In some embodiments, the RRC reconfiguration message includes bearer type configurations for one or more candidate MNs.

[0290] In some embodiments, the bearer type includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0291] Optionally, the RRC reconfiguration message may also include configuration information of the source MN, which may include the bearer type configuration of the source MN.

[0292] In some embodiments, the configuration information of each candidate MN can be included in an RRC reconfiguration message. That is, the RRC reconfiguration message sent by the source MN to the terminal device in step 1304 contains one or more RRC reconfiguration messages, each containing the configuration information of one or more candidate MNs.

[0293] In some embodiments, the configuration information of each candidate MN can be contained in an IE. That is, the RRC reconfiguration message sent by the source MN to the terminal device in 1304 contains one or more IEs, each containing the configuration information of one or more candidate MNs.

[0294] 1305. After receiving the RRC reconfiguration message, the terminal device sends an RRC reconfiguration complete message to the source MN. This RRC reconfiguration complete message is used to confirm the RRC reconfiguration message sent by the source MN in 1304.

[0295] 1306. The terminal device reports L1 measurements to the source MN.

[0296] The terminal device can perform L1 measurements and send L1 measurement reports based on the L1 measurement configuration. The L1 measurement configuration can be included in the RRC reconfiguration message in 1304.

[0297] 1307. The source MN sends the first processing information to the target MN, indicating the processing strategy configured by the SCG to the target MN.

[0298] In some embodiments, the first processing information may be transmitted via the Xn interface.

[0299] In some embodiments, the target MN may be determined by the source MN based on a measurement report received from the terminal device, wherein the measurement report may include, for example, the L3 measurement report in 1301 and / or the L1 measurement report in 1306.

[0300] 1308. The target MN sends an SN add request or a terminal device context release request to the SN based on the processing strategy configured in the SCG.

[0301] The target MN can determine the processing strategy for the SCG configuration in the LTM based on the first processing information received.

[0302] In some embodiments, the first processing information indicates that the SCG configuration should be released, and the target MN may send a terminal device context release request or an SCG configuration information release indication to the SN.

[0303] In some embodiments, the first processing information indicates that the SCG configuration is maintained, and the target MN can perform the SN addition process, that is, send an SN addition request to the SN and receive an SN addition request response from the SN, thereby realizing the addition of the SN.

[0304] In some embodiments, if the first indication information indicates the release of the SCG configuration, the source MN may directly send the first indication information to the SN, indicating the release of the SCG configuration and the release of the terminal device context to the SN.

[0305] 1309. The source MN sends an LTM switching command to the terminal device.

[0306] LTM switching commands can be used to indicate a switch from the source MN to one of one or more candidate MNs, i.e., the target MN.

[0307] The LTM handover command can be carried on the MAC CE or DCI. The LTM handover command indicates the target cell identifier for the terminal device's handover, or the target cell configuration identifier. The candidate MNs include the MN to which the target cell belongs, i.e., the target MN.

[0308] 1310. The source MN sends the first instruction information to the terminal device.

[0309] The first indication information is used to indicate the processing strategy for the SCG configuration in the LTM, which includes retaining or releasing the SCG configuration. Furthermore, the processing strategy for the SCG configuration indicated by the first processing information is the same as the processing strategy for the SCG configuration indicated by the first indication information in 1208.

[0310] In the LTM between MNs, the source MN can indicate to the terminal device, through the first indication information, whether the processing of the SCG configuration is to be retained or released, so that the terminal device can determine the change of bearer type after switching from the source MN to the target MN based on the RRC reconfiguration message, the LTM switching command, and the first indication information.

[0311] In some embodiments, the first indication information may be a dedicated signaling sent separately as shown in 1310.

[0312] In some embodiments, the first indication information may be carried by the LTM switching command in 1309, that is, 1309 and 1310 may be a single step.

[0313] In some embodiments, the first indication information may be included in, for example, LTM pre-configuration information in 1303 and 1304, and carried by an RRC message, such as an RRC reconfiguration message.

[0314] In some embodiments, the first indication information may be carried by DCI signaling.

[0315] In some embodiments, the first indication information may be carried by PDCCH signaling.

[0316] In some embodiments, the first indication information may be carried by PDSCH signaling.

[0317] In some embodiments, the first indication information may be determined by the source MN based on a measurement report received from the terminal device, wherein the measurement report may include the L3 measurement report in 1301 and / or the L1 measurement report in 1306.

[0318] In some embodiments, the first indication information may be determined by the source MN based on LTM handover request responses received from one or more candidate MNs, the LTM handover request responses including indications of the processing policy configured for the SCG.

[0319] 1311. The terminal device determines the change in bearer type and performs L2 processing.

[0320] The terminal device can determine the change in bearer type after switching from the source MN to the target MN based on the RRC reconfiguration message and LTM handover command received from the source MN, and perform L2 processing accordingly.

[0321] In some embodiments, a change in bearer type may include at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer.

[0322] In some embodiments, L2 processing may include at least one of the following: MAC layer reset; RLC layer re-establishment; PDCP layer re-establishment.

[0323] In some embodiments, if the terminal device also receives first indication information for indicating the processing strategy for SCG configuration in LTM, the terminal device can determine the change in bearer type after switching from source MN to target MN based on the RRC reconfiguration message, LTM switching command and the first indication information, and perform L2 processing.

[0324] In some embodiments, the first indication information indicates that the SCG configuration is retained in the LTM. The terminal device can determine the change in the bearer type corresponding to the MCG in the MN and the SCG in the SN after switching from the source MN to the target MN, and perform L2 processing, including: performing layer 2 processing corresponding to the MCG and SCG.

[0325] In some embodiments, the first indication information indicates that the SCG configuration in the LTM is released. The terminal device can determine that the SCG configuration is no longer retained after switching from the source MN to the target MN. Therefore, it only needs to determine the change of the bearer type corresponding to the MCG in the MN and perform L2 processing, including: performing the layer 2 processing corresponding to the MCG.

[0326] In some embodiments, the source MN or the target MN may send a third indication message to the SN, which is used to indicate that the SN configuration should be updated.

[0327] In some embodiments, the third indication information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer. Based on this, the SN can be aware of the change in bearer type in the LTM.

[0328] In some embodiments, the source MN or the target MN may send a fourth indication message, which is used to indicate the status information of the SCG configuration after LTM. For example, the source MN or the target MN notifies other candidate MNs that the SCG configuration information has been released or is in a reserved state, so that the candidate MNs update the status of the SCG-related configuration of the terminal device.

[0329] Referring to Figure 14, Figure 14 is a schematic diagram of the interaction between CUs under dual connectivity according to an embodiment of this application. As shown in Figure 14, the LTM process between MNs may include:

[0330] 1401. The terminal device reports the measurement to the source MN.

[0331] The terminal device can perform measurements according to the measurement configuration and report the measurement; the measurement configuration and report can be an L3 measurement configuration and report, and can be configured by the source MN.

[0332] 1402. The source MN sends an LTM handover request to one or more candidate MNs (including the target MN).

[0333] The source MN can refer to the reported results of the terminal device and / or its own handover algorithm to determine one or more candidate MNs of LTM. The target MN for subsequent handover can be included in the determined one or more candidate MNs. The one or more candidate MNs can be the MNs to which one or more candidate PCells belong.

[0334] 1403. The candidate MN sends an LTM switching request response to the source MN.

[0335] Candidate MNs can be pre-configured with LTM pre-configuration information for candidate MNs / candidate PCells, and the LTM handover request response can include this LTM pre-configuration information. The LTM pre-configuration information can include configuration information related to measurement reporting, cell identifier, handover conditions, etc., and can also be configured with configuration information to instruct the terminal on Layer 2 processing after handover, wherein Layer 2 processing can include MAC layer reset, RLC layer re-establishment, and PDCP layer re-establishment.

[0336] In some embodiments, the LTM handover request response sent by the candidate MN to the source MN further includes first indication information, which indicates the processing strategy for the SCG configuration in the LTM, including retaining or releasing the SCG configuration.

[0337] In some embodiments, the processing strategy configured by SCG can be pre-configured.

[0338] In some embodiments, since the LTM handover request in 1402 may include various information such as terminal device context information, bearer type and data path information, time synchronization and timing information, SCG configuration information, MAC and RLC layer resource information, the processing strategy of SCG configuration may be determined by the candidate MN in response to receiving the LTM handover request from the source MN in 1402.

[0339] In some embodiments, the processing strategy configured by the SCG of each candidate MN is applied to all candidate cells configured by that candidate MN, that is, each candidate MN is configured with the same processing strategy for all candidate cells to which it belongs.

[0340] In some embodiments, a candidate MN configures a processing strategy for each candidate cell in its candidate cell group.

[0341] 1404. The source MN sends an RRC reconfiguration message to the terminal device.

[0342] The RRC reconfiguration message may include LTM pre-configuration information received from candidate MNs. The LTM pre-configuration information contains configuration information for one or more candidate MNs.

[0343] The RRC reconfiguration message may also include first indication information associated with each of one or more candidate MNs.

[0344] In some embodiments, the RRC reconfiguration message includes bearer type configurations for one or more candidate MNs.

[0345] In some embodiments, the bearer type includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0346] Optionally, the RRC reconfiguration message may also include configuration information of the source MN, which may include the bearer type configuration of the source MN.

[0347] In some embodiments, the configuration information of each candidate MN can be included in an RRC reconfiguration message. That is, the RRC reconfiguration message sent by the source MN to the terminal device in step 1404 contains one or more RRC reconfiguration messages, each containing the configuration information of one or more candidate MNs.

[0348] In some embodiments, the configuration information of each candidate MN can be contained in an IE. That is, the RRC reconfiguration message sent by the source MN to the terminal device in 1404 contains one or more IEs, each containing the configuration information of one or more candidate MNs.

[0349] 1405. After receiving the RRC reconfiguration message, the terminal device sends an RRC reconfiguration complete message to the source MN. This RRC reconfiguration complete message is used to confirm the RRC reconfiguration message sent by the source MN in 1404.

[0350] 1406. The terminal device reports L1 measurements to the source MN.

[0351] The terminal device can perform L1 measurements and send L1 measurement reports based on the L1 measurement configuration. The L1 measurement configuration can be included in the RRC reconfiguration message in 1404.

[0352] 1407. The source MN sends an LTM switching command to the terminal device.

[0353] LTM switching commands can be used to indicate a switch from the source MN to one of one or more candidate MNs, i.e., the target MN.

[0354] The LTM handover command can be carried on the MAC CE or DCI. The LTM handover command indicates the target cell identifier for the terminal device's handover, or the target cell configuration identifier. The candidate MNs include the MN to which the target cell belongs, i.e., the target MN.

[0355] In some embodiments, the target MN may be determined by the source MN based on a measurement report received from the terminal device, wherein the measurement report may include, for example, the L3 measurement report in 1401 and / or the L1 measurement report in 1406.

[0356] 1408. The source MN sends a second indication message to the target MN. The second indication message is used to indicate the target cell for handover.

[0357] In some embodiments, the target cell may be determined based on the L1 measurement report in 1406.

[0358] 1409. Based on the processing strategy configured in the SCG and the second indication information, the target MN sends an SN add request or a terminal device context release request to the SN.

[0359] After receiving the second indication information, the target MN can determine the subsequent actions to be taken based on the processing strategy configured in the SCG corresponding to the target cell.

[0360] In some embodiments, the processing strategy for SCG configuration is to release the SCG configuration. In this case, the target MN sends a terminal device context release request or an SCG configuration information release instruction to the SN.

[0361] In some embodiments, the processing strategy for SCG configuration is to retain the SCG configuration. The target MN can execute the SN addition process, that is, send an SN addition request to the SN and receive an SN addition request response from the SN, thereby realizing the addition of the SN.

[0362] In some embodiments, if the first indication information indicates the release of the SCG configuration, the source MN may directly send the first indication information to the SN, indicating the release of the SCG configuration and the release of the terminal device context to the SN.

[0363] 1410. The terminal device determines the change in bearer type and performs L2 processing.

[0364] The terminal device can determine the change in bearer type after switching from the source MN to the target MN based on the RRC reconfiguration message and LTM handover command received from the source MN, and perform L2 processing accordingly.

[0365] In some embodiments, a change in bearer type may include at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer.

[0366] In some embodiments, L2 processing may include at least one of the following: MAC layer reset; RLC layer re-establishment; PDCP layer re-establishment.

[0367] In some embodiments, if the terminal device also receives first indication information for indicating the processing strategy for SCG configuration in LTM, the terminal device can determine the change in bearer type after switching from source MN to target MN based on the RRC reconfiguration message, LTM switching command and the first indication information, and perform L2 processing.

[0368] In some embodiments, the first indication information indicates that the SCG configuration is retained in the LTM. The terminal device can determine the change in the bearer type corresponding to the MCG in the MN and the SCG in the SN after switching from the source MN to the target MN, and perform L2 processing, including: performing layer 2 processing corresponding to the MCG and SCG.

[0369] In some embodiments, the first indication information indicates that the SCG configuration in the LTM is released. The terminal device can determine that the SCG configuration is no longer retained after switching from the source MN to the target MN. Therefore, it only needs to determine the change of the bearer type corresponding to the MCG in the MN and perform L2 processing, including: performing the layer 2 processing corresponding to the MCG.

[0370] In some embodiments, the source MN or the target MN may send a third indication message to the SN, which is used to indicate that the SN configuration should be updated.

[0371] In some embodiments, the third indication information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer. Based on this, the SN can be aware of the change in bearer type in the LTM.

[0372] In some embodiments, the source MN or the target MN may send a fourth indication message, which is used to indicate the status information of the SCG configuration after LTM. For example, the source MN or the target MN notifies other candidate MNs that the SCG configuration information has been released or is in a reserved state, so that the candidate MNs update the status of the SCG-related configuration of the terminal device.

[0373] Referring to Figure 15, Figure 15 is a schematic diagram of the interaction between CUs under dual connectivity according to an embodiment of this application. As shown in Figure 15, the LTM process between MNs may include:

[0374] 1501. The terminal device reports measurements to the source MN.

[0375] The terminal device can perform measurements according to the measurement configuration and report the measurement; the measurement configuration and report can be, for example, an L3 measurement configuration and report, and can be configured by the source MN.

[0376] 1502. The source MN sends an LTM handover request to one or more candidate MNs (including the target MN).

[0377] The source MN can refer to the reported results of the terminal device and / or its own handover algorithm to determine one or more candidate MNs of LTM. The target MN for subsequent handover can be included in the determined one or more candidate MNs. The one or more candidate MNs can be the MNs to which one or more candidate PCells belong.

[0378] 1503. The candidate MN determines the processing strategy of the SCG configuration and sends an SN add request or terminal device context release request to the SN.

[0379] Candidate MNs can determine the processing strategy for SCG configurations in LTMs, which includes retaining or releasing the SCG configurations.

[0380] In some embodiments, the processing strategy configured by SCG can be pre-configured.

[0381] In some embodiments, since the LTM handover request in 1502 may include various information such as terminal device context information, bearer type and data path information, time synchronization and timing information, SCG configuration information, MAC and RLC layer resource information, the processing strategy of SCG configuration may be determined by the candidate MN in response to receiving the LTM handover request from the source MN in 1502.

[0382] In some embodiments, the processing strategy configured by the SCG of each candidate MN is applied to all candidate cells configured by that candidate MN, that is, each candidate MN is configured with the same processing strategy for all candidate cells to which it belongs.

[0383] In some embodiments, a candidate MN configures a processing strategy for each candidate cell in its candidate cell group.

[0384] Candidate MNs can determine subsequent actions based on the processing strategy configured in the SCG.

[0385] In some embodiments, the processing strategy for SCG configuration is to release the SCG configuration. In this case, the candidate MN sends a terminal device context release request or a release instruction for SCG configuration information to the SN.

[0386] In some embodiments, the processing strategy for SCG configuration is to retain the SCG configuration. The candidate MN can execute the SN addition process, that is, send an SN addition request to the SN and receive an SN addition request response from the SN, thereby realizing the addition of the SN.

[0387] 1504. The candidate MN sends an LTM switching request response to the source MN.

[0388] Candidate MNs can be pre-configured with LTM pre-configuration information for candidate MNs / candidate PCells, and the LTM handover request response can include this LTM pre-configuration information. The LTM pre-configuration information can include configuration information related to measurement reporting, cell identifier, handover conditions, etc., and can also be configured with configuration information to instruct the terminal on Layer 2 processing after handover, wherein Layer 2 processing can include MAC layer reset, RLC layer re-establishment, and PDCP layer re-establishment.

[0389] In some embodiments, the LTM handover request response sent by the candidate MN to the source MN further includes first indication information, which indicates the processing strategy for the SCG configuration in the LTM determined in 1503, the processing strategy including retaining or releasing the SCG configuration.

[0390] 1505. The source MN sends an RRC reconfiguration message to the terminal device.

[0391] The RRC reconfiguration message may include LTM pre-configuration information received from candidate MNs. The LTM pre-configuration information contains configuration information for one or more candidate MNs.

[0392] The RRC reconfiguration message may also include first indication information associated with each of one or more candidate MNs.

[0393] In some embodiments, the RRC reconfiguration message includes bearer type configurations for one or more candidate MNs.

[0394] In some embodiments, the bearer type includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0395] Optionally, the RRC reconfiguration message may also include configuration information of the source MN, which may include the bearer type configuration of the source MN.

[0396] In some embodiments, the configuration information of each candidate MN can be included in an RRC reconfiguration message. That is, the RRC reconfiguration message sent by the source MN to the terminal device in step 1505 contains one or more RRC reconfiguration messages, each containing the configuration information of one or more candidate MNs.

[0397] In some embodiments, the configuration information of each candidate MN can be contained in an IE. That is, the RRC reconfiguration message sent by the source MN to the terminal device in 1505 contains one or more IEs, each containing the configuration information of one or more candidate MNs.

[0398] 1506. After receiving the RRC reconfiguration message, the terminal device sends an RRC reconfiguration completion message to the source MN. This RRC reconfiguration completion message is used to confirm the RRC reconfiguration message sent by the source MN in 1505.

[0399] 1507. The terminal device reports L1 measurements to the source MN.

[0400] The terminal device can perform L1 measurements and send L1 measurement reports based on the L1 measurement configuration. The L1 measurement configuration can be included in the RRC reconfiguration message in 1505.

[0401] 1508. The source MN sends an LTM switching command to the terminal device.

[0402] LTM switching commands can be used to indicate a switch from the source MN to one of one or more candidate MNs, i.e., the target MN.

[0403] The LTM handover command can be carried on the MAC CE or DCI. The LTM handover command indicates the target cell identifier for the terminal device's handover, or the target cell configuration identifier. The candidate MNs include the MN to which the target cell belongs, i.e., the target MN.

[0404] In some embodiments, the target MN may be determined by the source MN based on a measurement report received from the terminal device, wherein the measurement report may include the L3 measurement report in 1501 and / or the L1 measurement report in 1507.

[0405] 1509. The source MN sends a second indication message to the target MN. The second indication message is used to indicate the target cell for handover.

[0406] In some embodiments, the target cell may be determined based on the L1 measurement report in 1507.

[0407] 1510. The terminal device determines the change in bearer type and performs L2 processing.

[0408] The terminal device can determine the change in bearer type after switching from the source MN to the target MN based on the RRC reconfiguration message and LTM handover command received from the source MN, and perform L2 processing accordingly.

[0409] In some embodiments, a change in bearer type may include at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer.

[0410] In some embodiments, L2 processing may include at least one of the following: MAC layer reset; RLC layer re-establishment; PDCP layer re-establishment.

[0411] In some embodiments, if the terminal device also receives first indication information for indicating the processing strategy for SCG configuration in LTM, the terminal device can determine the change in bearer type after switching from source MN to target MN based on the RRC reconfiguration message, LTM switching command and the first indication information, and perform L2 processing.

[0412] In some embodiments, the first indication information indicates that the SCG configuration is retained in the LTM. The terminal device can determine the change in the bearer type corresponding to the MCG in the MN and the SCG in the SN after switching from the source MN to the target MN, and perform L2 processing, including: performing layer 2 processing corresponding to the MCG and SCG.

[0413] In some embodiments, the first indication information indicates that the SCG configuration in the LTM is released. The terminal device can determine that the SCG configuration is no longer retained after switching from the source MN to the target MN. Therefore, it only needs to determine the change of the bearer type corresponding to the MCG in the MN and perform L2 processing, including: performing the layer 2 processing corresponding to the MCG.

[0414] In some embodiments, the source MN or the target MN may send a third indication message to the SN, which is used to indicate that the SN configuration should be updated.

[0415] In some embodiments, the third indication information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer. Based on this, the SN can be aware of the change in bearer type in the LTM.

[0416] In some embodiments, the source MN or the target MN may send a fourth indication message, which is used to indicate the status information of the SCG configuration after LTM. For example, the source MN or the target MN notifies other candidate MNs that the SCG configuration information has been released or is in a reserved state, so that the candidate MNs update the status of the SCG-related configuration of the terminal device.

[0417] Scenario 2: LTM between SNs (inter-SN)

[0418] Referring to Figure 16, Figure 16 is a schematic diagram of the interaction between CUs under dual connectivity according to an embodiment of this application. As shown in Figure 16, the LTM process between SNs may include:

[0419] 1601. The terminal device reports measurements to the source SN.

[0420] The terminal device can perform measurements according to the measurement configuration and report the measurement; the measurement configuration and report can be an L3 measurement configuration and report, and can be configured by the source MN.

[0421] 1602. The source SN sends an LTM handover request to one or more candidate SNs (including the target SN).

[0422] The source SN can refer to the reported results of the terminal device and / or its own handover algorithm to determine one or more candidate SNs for LTM. The target SN for subsequent handover can be included in the determined one or more candidate SNs. The one or more candidate SNs can be the SNs to which one or more candidate PSCells belong.

[0423] 1603. The candidate SN sends an LTM handover request response to the source SN.

[0424] The candidate SN can be pre-configured with LTM pre-configuration information for the candidate SN / candidate PSCell, and the LTM handover request response can include this LTM pre-configuration information. The LTM pre-configuration information can include configuration information related to measurement reporting, cell identifier, handover conditions, etc., and can also be configured with configuration information to instruct the terminal on Layer 2 processing after handover occurs. Layer 2 processing can include MAC layer reset, RLC layer re-establishment, and PDCP layer re-establishment.

[0425] 1604. The source SN sends an RRC reconfiguration message to the MN.

[0426] 1605.MN sends an RRC reconfiguration message to the terminal device.

[0427] The RRC reconfiguration message may include LTM pre-configuration information sent by the candidate SN. The LTM pre-configuration information contains configuration information for one or more candidate SNs.

[0428] In some embodiments, the RRC reconfiguration message includes bearer type configurations for one or more candidate SNs.

[0429] In some embodiments, the bearer type includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0430] Optionally, the RRC reconfiguration message may also include configuration information of the source SN, which may include the bearer type configuration of the source SN.

[0431] In some embodiments, the configuration information of each candidate SN can be included in an RRC reconfiguration message. That is, the RRC reconfiguration message sent by the source SN to the MN in 1604 and the RRC reconfiguration message sent by the MN to the terminal device in 1605 contain one or more RRC reconfiguration messages, each containing the configuration information of one or more candidate SNs.

[0432] In some embodiments, the configuration information of each candidate MN can be contained in an IE. That is, the RRC reconfiguration message sent from the source SN to the MN in 1604 and the RRC reconfiguration message sent from the MN to the terminal device in 1605 contain one or more IEs, each containing the configuration information of one or more candidate SNs.

[0433] In some embodiments, the source SN may send RRC reconfiguration messages directly to the terminal device without going through the MN.

[0434] 1606. After receiving the RRC reconfiguration message, the terminal device sends an RRC reconfiguration complete message to the MN. This RRC reconfiguration complete message is used to confirm the RRC reconfiguration message sent by the MN in 1605.

[0435] 1607. The terminal device reports L1 measurements to the source SN.

[0436] The terminal device can perform L1 measurements and send L1 measurement reports based on the L1 measurement configuration. The L1 measurement configuration can be included in the RRC reconfiguration messages in 1604 and 1605.

[0437] 1608. The source SN sends an LTM handover command to the terminal device.

[0438] LTM switching commands can be used to indicate a switch from a source SN to one of one or more candidate SNs, i.e., the target SN.

[0439] The LTM handover command can be carried on the MAC CE or DCI. The LTM handover command indicates the target cell identifier for the terminal equipment to hand over, or indicates the target cell configuration identifier for the terminal equipment to hand over. The candidate SNs include the SN to which the target cell belongs, i.e., the target SN.

[0440] In some embodiments, the target SN may be determined by the source SN based on a measurement report received from the terminal device, wherein the measurement report may include the L3 measurement report in 1601 and / or the L1 measurement report in 1607.

[0441] 1609. The source SN sends a second indication message to the target SN. The second indication message is used to indicate the target cell for handover.

[0442] In some embodiments, the target cell may be determined based on the L1 measurement report in 1607.

[0443] 1610. The terminal device determines the change in bearer type and performs L2 processing.

[0444] The terminal device can determine the change in bearer type after switching from the source SN to the target SN based on the RRC reconfiguration message and LTM handover command received from the MN or source SN, and perform L2 processing accordingly.

[0445] In some embodiments, a change in bearer type may include at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer.

[0446] In some embodiments, L2 processing may include at least one of the following: MAC layer reset; RLC layer re-establishment; PDCP layer re-establishment.

[0447] In some embodiments, the source SN or the target SN may send a fifth indication message to the MN, which indicates that the MN configuration should be updated.

[0448] In some embodiments, the fifth indication information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer. Based on this, the MN can be aware of the change in bearer type in the LTM.

[0449] Referring to Figure 17, Figure 17 is a schematic diagram of the interaction between CUs under dual connectivity according to an embodiment of this application. As shown in Figure 17, the LTM process between SNs may include:

[0450] 1701. The source SN sends an SN change request to the MN.

[0451] The source SN can determine the need for handover based on the communication environment, such as the reported results from the terminal device and / or its own handover algorithm, and send an SN change request to the MN, requesting the MN to perform a handover between SNs.

[0452] 1702.MN sends an SN add request to one or more candidate SNs (including the target SN).

[0453] In response to receiving an SN change request from the source SN, the MN may refer to the reported results of the terminal device and / or its own handover algorithm to determine one or more candidate SNs for LTM. The target SN for subsequent handover may be included in the determined one or more candidate SNs. The one or more candidate SNs may be the SNs to which one or more candidate PSCells belong.

[0454] 1703. The candidate SN sends an SN add request response to the MN.

[0455] Candidate SNs can be pre-configured with LTM pre-configuration information for candidate SNs / candidate PSCells, and the SN add request response can include this LTM pre-configuration information. The LTM pre-configuration information can include configuration information related to measurement reporting, cell identifier, handover conditions, etc., and can also be configured with configuration information to instruct the terminal on Layer 2 processing after handover, wherein Layer 2 processing can include MAC layer reset, RLC layer re-establishment, and PDCP layer re-establishment.

[0456] 1704.MN sends an RRC reconfiguration message to the terminal device.

[0457] The RRC reconfiguration message may include LTM pre-configuration information sent by the candidate SN. The LTM pre-configuration information contains configuration information for one or more candidate SNs.

[0458] In some embodiments, the RRC reconfiguration message includes bearer type configurations for one or more candidate SNs.

[0459] In some embodiments, the bearer type includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0460] Optionally, the RRC reconfiguration message may also include configuration information of the source SN, which may include the bearer type configuration of the source SN.

[0461] In some embodiments, the configuration information of each candidate SN can be included in an RRC reconfiguration message. That is, the RRC reconfiguration message sent by the MN to the terminal device in step 1704 includes one or more RRC reconfiguration messages, each containing the configuration information of one or more candidate SNs.

[0462] In some embodiments, the configuration information of each candidate MN can be contained in an IE. That is, the RRC reconfiguration message sent by the MN to the terminal device in step 1704 contains one or more IEs, each containing the configuration information of one or more candidate SNs.

[0463] 1705. After receiving the RRC reconfiguration message, the terminal device sends an RRC reconfiguration complete message to the MN. This RRC reconfiguration complete message is used to confirm the RRC reconfiguration message sent by the MN in 1704.

[0464] 1706. The terminal device reports L1 measurements to the source SN.

[0465] The terminal device can perform L1 measurements and send L1 measurement reports based on the L1 measurement configuration. The L1 measurement configuration can be included in the RRC reconfiguration message in 1704.

[0466] 1707. The source SN sends an LTM handover command to the terminal device.

[0467] LTM switching commands can be used to indicate a switch from a source SN to one of one or more candidate SNs, i.e., the target SN.

[0468] The LTM handover command can be carried on the MAC CE or DCI. The LTM handover command indicates the target cell identifier for the terminal equipment to hand over, or indicates the target cell configuration identifier for the terminal equipment to hand over. The candidate SNs include the SN to which the target cell belongs, i.e., the target SN.

[0469] In some embodiments, the target SN may be determined by the source SN based on a measurement report received from the terminal device, wherein the measurement report may include an L3 measurement report and / or an L1 measurement report in 1706.

[0470] 1708. The source SN sends a second indication message to the target SN. The second indication message is used to indicate the target cell for handover.

[0471] In some embodiments, the target cell may be determined based on the L1 measurement report in 1706.

[0472] 1709. The terminal device determines the change in bearer type and performs L2 processing.

[0473] The terminal device can determine the change in bearer type after switching from the source SN to the target SN based on the RRC reconfiguration message received from the MN and the LTM handover command from the source SN, and perform L2 processing accordingly.

[0474] In some embodiments, a change in bearer type may include at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer.

[0475] In some embodiments, L2 processing may include at least one of the following: MAC layer reset; RLC layer re-establishment; PDCP layer re-establishment.

[0476] In some embodiments, the source SN or the target SN may send a fifth indication message to the MN, which indicates that the MN configuration should be updated.

[0477] In some embodiments, the fifth indication information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; and a change between an MN-terminated bearer and an SN-terminated bearer. Based on this, the MN can be aware of the change in bearer type in the LTM.

[0478] It is understood that multiple embodiments have been described in detail above with reference to several flowcharts. However, it should be understood that these flowcharts and their corresponding descriptions are merely illustrative for ease of understanding and should not constitute any limitation on this application. Not every step in each flowchart is necessarily required to be performed; for example, some steps can be skipped. Furthermore, the execution order of each step is not fixed and is not limited to what is shown in the flowcharts. The execution order of each step should be determined by its function and internal logic.

[0479] It can also be understood that the LTM between MNs in scenario one and the LTM between SNs in scenario two, as described above regarding LTM between CUs under dual connectivity, are not mutually exclusive events. That is, LTM between SNs can occur while LTM between MNs is being executed, or LTM between MNs can occur while LTM between SNs is being executed. The terminal device can execute Layer 2 processing on the MN and SN sides respectively, depending on the specific circumstances. Layer 2 processing may include one or more of PDCP re-establishment, RLC re-establishment, and MAC layer reset.

[0480] Figure 18 is a flowchart illustrating a communication method provided in an embodiment of this application. The method execution entity shown in Figure 18 can be a terminal device, or the entity can be a chip within the terminal device. Wherein:

[0481] S1801. Receive Radio Resource Control (RRC) reconfiguration message, the RRC reconfiguration message including preconfiguration information of one or more second primary network devices or one or more second secondary network devices.

[0482] S1802. Receive Layer 1 / Layer 2 triggered Mobility LTM handover command. The LTM handover command is used to indicate a handover from a first primary network device to one or more second primary network devices, or to indicate a handover from a first secondary network device to one or more second secondary network devices.

[0483] S1803. Based on the RRC reconfiguration message and LTM switching command, determine the change of bearer type.

[0484] S1804. Based on the determined change in bearer type, perform layer 2 processing.

[0485] Based on the method shown in Figure 18, the terminal device can receive an RRC reconfiguration message containing pre-configuration information of the target network device and an LTM switching command. It can determine the change of bearer type based on the RRC reconfiguration message and the LTM switching command, and perform layer 2 processing based on the change of bearer type. This is beneficial for protocol stack reconstruction based on bearer change adaptability in the dual-connectivity LTM process, which is conducive to achieving data transmission continuity, reducing service interruption, and improving the efficiency of LTM under dual connectivity.

[0486] In one possible implementation, the pre-configuration information includes bearer type configuration, wherein the bearer class includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0487] In one possible implementation, an RRC reconfiguration message and an LTM handover command are received from a first primary network device. The RRC reconfiguration message includes pre-configuration information of one or more second primary network devices, and the LTM handover command indicates a handover from the first primary network device to one or more second primary network devices. The method further includes: receiving first indication information from the first primary network device, the first indication information indicating a processing strategy for secondary cell group (SCG) configuration in the LTM, the processing strategy including retaining or releasing the SCG configuration; and determining a change in bearer type based on the RRC reconfiguration message and the LTM handover command, including determining the change in bearer type based on the RRC reconfiguration message, the LTM handover command, and the first indication information.

[0488] In some embodiments, the second primary network device indicated by the LTM handover command may be determined by the first primary network device from one or more second primary network devices based on a measurement report received from the terminal device, wherein the measurement report may include an L3 measurement report and / or an L1 measurement report.

[0489] In some embodiments, the first indication information may be a separately sent dedicated signaling.

[0490] In some embodiments, the first indication information may be carried by the LTM switching command.

[0491] In some embodiments, the first indication information may be pre-configured, for example, it may be included in the LTM pre-configuration information and may be carried by the RRC reconfiguration message.

[0492] In some embodiments, the first indication information may be carried by DCI signaling.

[0493] In some embodiments, the first indication information may be carried by PDCCH signaling.

[0494] In some embodiments, the first indication information may be carried by PDSCH signaling.

[0495] Based on this implementation, the change of bearer type can be determined according to the processing policy indication information configured in SCG, without having to wait for LTM to determine whether SCG is configured to retain or release and to determine the change of growth type. This is conducive to timely L2 processing and protocol stack reconstruction, which is beneficial to achieve data transmission continuity, reduce service interruption, and improve the efficiency of LTM under dual connection.

[0496] In one possible implementation, the first indication information instructs the LTM to retain the SCG configuration and perform Layer 2 processing, including performing Layer 2 processing corresponding to the primary cell group MCG and SCG.

[0497] Based on this implementation, the protocol stack can be adaptively rebuilt according to changes in bearer type during LTM handover, ensuring the continuity of data transmission.

[0498] In one possible implementation, the first instruction information instructs the LTM to release the SCG configuration and perform layer 2 processing, including performing layer 2 processing corresponding to the MCG.

[0499] Based on this implementation, the protocol stack can be adaptively rebuilt according to changes in bearer type during LTM handover, ensuring the continuity of data transmission.

[0500] In one possible implementation, the RRC reconfiguration message and the LTM handover command are received from the first primary network device or the first secondary network device. The RRC reconfiguration message includes preconfiguration information of one or more secondary network devices. The LTM handover command indicates a handover from the first secondary network device to one or more secondary network devices and performs Layer 2 processing, including performing Layer 2 processing corresponding to the SCG.

[0501] Based on this implementation, the protocol stack can be adaptively rebuilt according to changes in bearer type during LTM handover, ensuring the continuity of data transmission.

[0502] In some embodiments, the second secondary network device indicated by the LTM handover command may be determined by the first secondary network device from one or more second secondary network devices based on a measurement report received from the terminal device, wherein the measurement report may include an L3 measurement report and / or an L1 measurement report.

[0503] In one possible implementation, the change of bearer type is characterized by including at least one of the following: a change between MCG bearer and SCG bearer; a change between MCG bearer and split bearer; a change between SCG bearer and split bearer; a change between primary network device MN-terminated bearer and secondary network device SN-terminated bearer.

[0504] In one possible implementation, the layer 2 processing includes at least one of the following: Media Access Control (MAC) layer reset; Radio Link Control (RLC) layer re-establishment; Packet Data Convergence Protocol (PDCP) layer re-establishment.

[0505] Figure 19 is a schematic flowchart of a communication processing method provided in an embodiment of this application. The method execution entity shown in Figure 19 can be a network device, or the entity can be a chip within the network device. Wherein:

[0506] S1901. Send a Radio Resource Control (RRC) reconfiguration message to the terminal device. The RRC reconfiguration message includes preconfiguration information of one or more second primary network devices or one or more second secondary network devices.

[0507] S1902. Send a Layer 1 / Layer 2 Triggered Mobility LTM handover command to the terminal device. The LTM handover command is used to indicate a handover from a first primary network device to one or more second primary network devices, or to indicate a handover from a first secondary network device to one or more second secondary network devices.

[0508] Based on the method described in the second aspect, by sending an RRC reconfiguration message including the pre-configuration information of the target network device and an LTM switching command to the terminal device, the terminal device can determine the change of bearer type based on the RRC reconfiguration message and the LTM switching command, and perform layer 2 processing based on the change of bearer type. This is beneficial for protocol stack reconstruction based on bearer change adaptability in the dual-connectivity LTM process, which helps to achieve data transmission continuity, reduce service interruption, and improve the efficiency of LTM under dual connectivity.

[0509] In one possible implementation, the pre-configuration information includes bearer type configuration, wherein the bearer class includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0510] In one possible implementation, the RRC reconfiguration message includes pre-configuration information of one or more second primary network devices, and the LTM handover command is used to indicate a handover from a first primary network device to one or more second primary network devices. The method further includes sending a first indication message to a terminal device, the first indication message being used to indicate a processing strategy for the secondary cell group (SCG) configuration in LTM, the processing strategy including retaining or releasing the SCG configuration.

[0511] In some embodiments, the second primary network device indicated by the LTM handover command may be determined by the first primary network device from one or more second primary network devices based on a measurement report received from the terminal device, wherein the measurement report may include an L3 measurement report and / or an L1 measurement report.

[0512] In some embodiments, the first indication information may be a separately sent dedicated signaling.

[0513] In some embodiments, the first indication information may be carried by the LTM switching command.

[0514] In some embodiments, the first indication information may be pre-configured, for example, it may be included in the LTM pre-configuration information and may be carried by the RRC reconfiguration message.

[0515] In some embodiments, the first indication information may be carried by DCI signaling.

[0516] In some embodiments, the first indication information may be carried by PDCCH signaling.

[0517] In some embodiments, the first indication information may be carried by PDSCH signaling.

[0518] Based on this implementation, the processing policy indication information configured by SCG can be used to indicate the change of bearer type to the terminal device. This eliminates the need for the terminal device to wait for LTM to determine whether the SCG configuration is to retain or release and to determine the change of growth type. This is beneficial for timely L2 processing and protocol stack reconstruction, which helps to achieve data transmission continuity, reduce service interruptions, and improve the efficiency of LTM under dual connectivity.

[0519] In one possible implementation, the first indication information is determined based on a measurement report received from the terminal device, wherein the measurement report includes a Layer 3 measurement report and / or a Layer 1 measurement report.

[0520] Based on this implementation method, the source and host network devices can flexibly determine the processing strategy of SCG configuration, which is beneficial for flexibly configuring dual connections of terminal devices according to the communication environment.

[0521] In one possible implementation, the method further includes: sending first processing information to one of one or more second master network devices, the first processing information being used to indicate a processing policy regarding SCG configuration in LTM, the processing policy regarding SCG configuration indicated by the first processing information being the same as the processing policy regarding SCG configuration indicated by the first indication information.

[0522] Based on this implementation method, the target primary network device can be instructed on the processing strategy of SCG configuration, which is conducive to the target primary network device configuring secondary network devices in a timely manner and improving the efficiency of LTM under dual connectivity.

[0523] In one possible implementation, the first processing information is transmitted via the Xn interface.

[0524] In one possible implementation, the first indication information is determined based on an LTM handover request response received from one or more second master network devices, the LTM handover request response including an indication of the processing policy for the SCG configuration.

[0525] In one possible implementation, the method further includes sending a second indication message to one of one or more second primary network devices, the second indication message indicating the target cell for handover, the target cell being determined based on a Layer 1 measurement report received from the terminal device.

[0526] Based on this implementation, the source network device can determine the cell that the terminal device needs to switch to according to the communication environment, and indicate the target cell to the target network device. This is beneficial for the target network device to configure the secondary network device in a timely manner, and it is also beneficial to improve the efficiency of LTM under dual connectivity.

[0527] In one possible implementation, the method further includes sending a third indication message to the secondary network device (SN), the third indication message being used to indicate that the SN configuration should be updated.

[0528] Based on this implementation, the primary network device can instruct the secondary network device to update the configuration of the terminal device, which helps to improve the efficiency of LTM under dual connectivity.

[0529] In one possible implementation, the third instruction information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; a change between a primary network device MN-terminated bearer and a secondary network device SN-terminated bearer.

[0530] In one possible implementation, the method further includes sending a fourth indication message, which is used to indicate the status information of the SCG configuration after LTM.

[0531] Based on this implementation method, it is beneficial for all candidate network devices in the communication system to update the SCG-related configuration status of the terminal device, thus avoiding potential failures or errors in the subsequent LTM due to inconsistent SCG configuration status.

[0532] In one possible implementation, the RRC reconfiguration message includes pre-configuration information for one or more second auxiliary network devices, and the LTM handover command is used to indicate a handover from the first auxiliary network device to one of the one or more second auxiliary network devices. The method further includes sending a fifth indication message to the primary network device MN, the fifth indication message being used to indicate an update to the MN configuration.

[0533] In some embodiments, the second secondary network device indicated by the LTM handover command may be determined by the first secondary network device from one or more second secondary network devices based on a measurement report received from the terminal device, wherein the measurement report may include an L3 measurement report and / or an L1 measurement report.

[0534] Based on this implementation, the secondary network device can notify the primary network device about the terminal device's configuration update, which helps improve the efficiency of LTM under dual connectivity.

[0535] In one possible implementation, sending a Radio Resource Control (RRC) reconfiguration message to a terminal device includes: sending the RRC reconfiguration message to the terminal device via the MN.

[0536] In one possible implementation, the fifth instruction information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; a change between a primary network device MN-terminated bearer and a secondary network device SN-terminated bearer.

[0537] Figure 20 is a flowchart illustrating a communication processing method provided in an embodiment of this application. The method execution entity shown in Figure 20 can be a network device, or the entity can be a chip within the network device. Wherein:

[0538] S2001. Receive a Layer 1 / Layer 2 triggered Mobility LTM handover request from the first primary network device.

[0539] S2002. Send an LTM handover request response to the first primary network device. The LTM handover request response includes pre-configuration information.

[0540] S2003. Determine the processing strategy for the secondary cell group (SCG) configuration in LTM. The processing strategy includes retaining or releasing the SCG configuration.

[0541] S2004. Based on the processing strategy configured in SCG, send an SN add request or a terminal device context release request to the secondary network device SN.

[0542] Based on the method described in the third aspect, the target primary network device can determine the processing strategy for SCG configuration and perform timely configuration of the secondary network device according to the corresponding processing strategy, which is beneficial to improving the efficiency of LTM under dual connectivity.

[0543] In one possible implementation, the pre-configuration information includes bearer type configuration, wherein the bearer class includes at least one of the following: primary cell group (MCG) bearer; secondary cell group (SCG) bearer; split bearer.

[0544] In one possible implementation, the method further includes: the processing policy of the SCG configuration is determined based on first processing information received from the first master network device, the first processing information being used to indicate the processing policy of the SCG configuration in the LTM.

[0545] In one possible implementation, the first processing information is transmitted via the Xn interface.

[0546] In one possible implementation, the processing policy configured by the SCG is pre-configured or determined in response to an LTM handover request received from the first primary network device. Based on the processing policy configured by the SCG, an SN add request or a terminal device context release request is sent to the secondary network device SN, including: receiving second indication information from the first primary network device, the second indication information being used to indicate the target cell for handover; and sending an SN add request or a terminal device context release request to the SN based on the processing policy configured by the SCG and the second indication information.

[0547] Based on this implementation, the target primary network device can configure the secondary network device in a timely manner, which is beneficial to improving the efficiency of LTM under dual connectivity.

[0548] In one possible implementation, the method further includes sending a third indication message to the SN, the third indication message being used to indicate that the SN configuration should be updated.

[0549] Based on this implementation, the target primary network device can instruct the secondary network device to update the configuration of the terminal device, which helps to improve the efficiency of LTM under dual connectivity.

[0550] In one possible implementation, the third instruction information indicates at least one of the following: a change between an MCG bearer and an SCG bearer; a change between an MCG bearer and a split bearer; a change between an SCG bearer and a split bearer; a change between a primary network device MN-terminated bearer and a secondary network device SN-terminated bearer.

[0551] In one possible implementation, the method further includes sending a fourth indication message, which is used to indicate the status information of the SCG configuration after LTM.

[0552] Based on this implementation method, it is beneficial for all candidate network devices in the communication system to update the SCG-related configuration status of the terminal device, thus avoiding potential failures or errors in the subsequent LTM due to inconsistent SCG configuration status.

[0553] Figure 21 is a schematic diagram of the structure of a communication device according to an embodiment of this application. The communication device 2100 shown in Figure 21 can be a terminal device, a device in a terminal device, or a device that can be used in conjunction with a terminal device; or the communication device shown in Figure 21 can be a network device, a device in a network device, or a device that can be used in conjunction with a network device.

[0554] The communication device 2100 shown in Figure 21 may include a communication unit 2101 and a processing unit 2102. Specifically, the processing unit 2102 is used to process data, which may be data received by the communication unit 2101, and the processed data may also be sent by the communication unit 2101.

[0555] Specifically, the processing unit 2102 is used to perform the data processing function of the terminal device or network device in the aforementioned method embodiments. For other possible implementations of the communication device, please refer to the relevant descriptions of the functions of the terminal device or network device in the method embodiments corresponding to Figures 18 to 20 above, which will not be repeated here.

[0556] Figure 22 is a schematic diagram of a communication device provided in an embodiment of this application. The communication device 2200 can be a terminal device or network device as described in the above method embodiments, or it can be a chip, chip system, or processor that supports the terminal device or network device in implementing the above methods. This communication device can be used to implement the methods described in the above method embodiments; for details, please refer to the descriptions in the above method embodiments.

[0557] The communication device 2200 may include one or more processors 2201. The processor 2201 may be a general-purpose processor or a dedicated processor, such as a baseband processor or a central processing unit (CPU). The baseband processor can be used to process communication protocols and communication data, while the CPU can be used to control the communication device (e.g., base station, baseband chip, terminal, terminal chip, DU or CU, etc.), execute software programs, and process data from the software programs.

[0558] Optionally, the communication device 2200 may include one or more memories 2202, which may store instructions 2204. These instructions can be executed on the processor 2201, causing the communication device 2200 to perform the methods described in the above method embodiments. Optionally, the memories 2202 may also store data. The processor 2201 and the memories 2202 may be configured separately or integrated together.

[0559] Optionally, the communication device 2200 may further include a transceiver 2205 and an antenna 2206. The transceiver 2205, also known as a transceiver unit, transceiver, or transceiver circuit, is used to implement transmission and reception functions. The transceiver 2205 may include a receiver and a transmitter. The receiver, also known as a receiver circuit, is used to implement a receiving function; the transmitter, also known as a transmitter or transmitting circuit, is used to implement a transmitting function. The processing unit 2102 shown in Figure 21 may be a processor 2201. The communication unit 2101 may be the transceiver 2205.

[0560] In another possible design, the processor 2201 may include a transceiver for implementing receive and transmit functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing receive and transmit functions may be separate or integrated. The aforementioned transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or it may be used for transmitting or relaying signals.

[0561] In another possible design, the processor 2201 may optionally store instructions 2203, which, when executed on the processor 2201, cause the communication device 2200 to perform the methods described in the above method embodiments. Instructions 2203 may be embedded in the processor 2201; in this case, the processor 2201 may be implemented in hardware.

[0562] The communication device described in the above embodiments can be a terminal device or a network device, but the scope of the communication device described in the embodiments of this application is not limited thereto, and the structure of the communication device is not limited to FIG22. The communication device can be a standalone device or part of a larger device. For example, the communication device can be:

[0563] (1) Independent integrated circuit IC, or chip, or chip system or subsystem;

[0564] (2) A collection of one or more ICs, optionally including a storage component for storing data and instructions;

[0565] (3) ASIC, such as modem (MSM);

[0566] (4) Modules that can be embedded in other devices;

[0567] (5) Receivers, terminals, smart terminals, cellular phones, wireless devices, handheld devices, mobile units, vehicle-mounted devices, network devices, cloud devices, artificial intelligence devices, etc.

[0568] (6) Others, etc.

[0569] For communication devices that can be chips or chip systems, please refer to the schematic diagram of the chip structure shown in Figure 23. The chip 2300 shown in Figure 23 includes a processor 2301 and an interface 2302. Optionally, it may also include a memory 2303. The number of processors 2301 can be one or more, and the number of interfaces 2302 can be multiple.

[0570] For cases where the chip is used to implement the terminal device or network device in the embodiments of this application:

[0571] Interface 2302 is used to receive or output signals;

[0572] Processor 2301 is used to perform data processing operations on terminal devices or network devices.

[0573] It is understood that some optional features in the embodiments of this application can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Accordingly, the communication device given in the embodiments of this application can also implement these features or functions, which will not be elaborated here.

[0574] It should be understood that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the above method embodiments can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor described above can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0575] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0576] This application also provides a computer-readable medium storing a computer program or instructions, which, when executed by a communication device, implements the functions of any of the above method embodiments.

[0577] This application also provides a computer program product including instructions, which, when read and executed by a computer, causes the computer to perform the functions of any of the above method embodiments.

[0578] This application provides a communication system, which includes a terminal device and a network device; wherein the terminal device is used to execute the method executed by the terminal device in the above embodiments, and the network device is used to execute the method executed by the network device in the above embodiments.

[0579] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0580] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some operations can be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0581] The descriptions of the various embodiments provided in this application can be referenced mutually. Each embodiment has its own emphasis, and parts not described in detail in a certain embodiment can be referred to the relevant descriptions of other embodiments. For the sake of convenience and brevity, for example, the functions and operations of the various devices and equipment provided in the embodiments of this application can be referred to the relevant descriptions of the method embodiments of this application. The method embodiments and the device embodiments can also be referenced, combined or cited from each other.

[0582] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

A communication processing method, applied to a terminal device, characterized in that, The method includes: Receive a Radio Resource Control (RRC) reconfiguration message, wherein the RRC reconfiguration message includes preconfiguration information of one or more second primary network devices or one or more second secondary network devices; The receiver receives a Layer 1 / Layer 2 triggered Mobility LTM handover command, which is used to indicate a handover from a first primary network device to one of the one or more second primary network devices, or to indicate a handover from a first secondary network device to one of the one or more second secondary network devices. Based on the RRC reconfiguration message and the LTM switching command, the change in bearer type is determined; Based on the determined change in bearer type, the processing of layer 2 is performed. The method according to claim 1, characterized in that, The RRC reconfiguration message and the LTM handover command are received from the first primary network device. The RRC reconfiguration message includes pre-configuration information of the one or more second primary network devices. The LTM handover command indicates a handover from the first primary network device to one of the one or more second primary network devices. The method further includes: Receive first indication information from the first primary network device, the first indication information being used to indicate the processing strategy for the secondary cell group (SCG) configuration in LTM, the processing strategy including retaining or releasing the SCG configuration; Based on the RRC reconfiguration message and the LTM switching command, the change in bearer type is determined, including: Based on the RRC reconfiguration message, the LTM switching command, and the first indication information, the change in bearer type is determined. The method according to claim 2, characterized in that, The first indication information is carried by any one of the following signaling methods: RRC signaling; Downlink Control Information (DCI) signaling; Physical downlink control channel (PDCCH) signaling; Physical downlink shared channel (PDSCH) signaling. The method according to claim 2, characterized in that, The first indication information instructs the LTM to retain the SCG configuration, and the processing of the execution layer 2 includes: Perform Layer 2 processing corresponding to the primary cell group MCG and SCG. The method according to claim 2, characterized in that, The first indication information instructs the LTM to release the SCG configuration, and the processing of the execution layer 2 includes: Perform the processing for layer 2 corresponding to MCG. The method according to claim 1, characterized in that, The RRC reconfiguration message and the LTM handover command are received from the first primary network device or the first secondary network device. The RRC reconfiguration message includes pre-configuration information of the one or more second secondary network devices. The LTM handover command indicates a handover from the first secondary network device to one of the one or more second secondary network devices. The processing of execution layer 2 includes: Perform the processing for layer 2 corresponding to SCG. The method according to any one of claims 1-6, characterized in that, The pre-configuration information includes bearer type configuration, and the bearer class includes at least one of the following: The main cell group's MCG bearer; SCG bearer in auxiliary cell group; Split the load. The method according to claim 7, characterized in that, The change in bearer type includes at least one of the following: Changes between MCG and SCG bearers; Changes between MCG bearers and split bearers; Changes between SCG bearer and split bearer; Changes between the primary network device MN terminal bearer and the secondary network device SN terminal bearer. The method according to claim 7, characterized in that, The processing of layer 2 includes at least one of the following: Media Access Control (MAC) layer reset; Radio Link Control (RLC) layer re-establishment; The Packet Data Convergence Protocol (PDCP) layer is re-established. A communication processing method, applied to a first primary network device or a first secondary network device, characterized in that, The method includes: Send a Radio Resource Control (RRC) reconfiguration message to the terminal device. The RRC reconfiguration message includes preconfiguration information of one or more second primary network devices or one or more second secondary network devices. A Layer 1 / Layer 2 Triggered Mobility LTM handover command is sent to the terminal device. The LTM handover command is used to indicate a handover from the first primary network device to one of the one or more secondary primary network devices, or to indicate a handover from the first secondary network device to one of the one or more secondary secondary network devices. The method according to claim 10, characterized in that, The pre-configuration information includes bearer type configuration, and the bearer class includes at least one of the following: The main cell group's MCG bearer; SCG bearer in auxiliary cell group; Split the load. The method according to claim 10, characterized in that, The RRC reconfiguration message includes pre-configuration information of the one or more second primary network devices, the LTM handover command is used to indicate a handover from the first primary network device to one of the one or more second primary network devices, and the method further includes: Send a first indication message to the terminal device. The first indication message is used to indicate the processing strategy for the secondary cell group (SCG) configuration in LTM. The processing strategy includes retaining or releasing the SCG configuration. The method according to claim 12, characterized in that, The first indication information is carried by any one of the following signaling methods: RRC signaling; Downlink Control Information (DCI) signaling; Physical downlink control channel (PDCCH) signaling; Physical downlink shared channel (PDSCH) signaling. The method according to claim 12, characterized in that, The first indication information is determined based on a measurement report received from the terminal device, wherein the measurement report includes a layer 3 measurement report and / or a layer 1 measurement report. The method according to claim 14, characterized in that, The method further includes: Send first processing information to one of the one or more second master network devices, the first processing information being used to indicate a processing policy regarding SCG configuration in LTM, the processing policy regarding SCG configuration indicated by the first processing information being the same as the processing policy regarding SCG configuration indicated by the first indication information. The method according to claim 15, characterized in that, The first processing information is transmitted via the Xn interface. The method according to claim 12, characterized in that, The first indication information is determined based on the LTM handover request response received from the one or more second primary network devices, the LTM handover request response including an indication of the processing policy configured for the SCG. The method according to claim 17, characterized in that, The method further includes: Send a second indication message to one of the one or more second primary network devices, the second indication message indicating the target cell for handover, the target cell being determined based on a Layer 1 measurement report received from the terminal device. The method according to any one of claims 12-18, characterized in that, The method further includes: A third indication message is sent to the secondary network device (SN), the third indication message being used to indicate that the SN configuration should be updated. The method according to claim 19, characterized in that, The third indication information indicates at least one of the following: Changes between MCG and SCG bearers; Changes between MCG bearers and split bearers; Changes between SCG bearer and split bearer; Changes between the primary network device MN terminal bearer and the secondary network device SN terminal bearer. The method according to any one of claims 12-18, characterized in that, The method further includes: Send a fourth indication message, which is used to indicate the status information of the SCG configuration after LTM. The method according to claim 10, characterized in that, The RRC reconfiguration message includes bearer type configurations for one or more second secondary network devices, the LTM handover command is used to indicate a handover from the first secondary network device to one of the one or more second secondary network devices, and the method further includes: A fifth instruction message is sent to the main network device MN, which is used to instruct the MN configuration to be updated. The method according to claim 22, characterized in that, Sending the Radio Resource Control (RRC) reconfiguration message to the terminal device includes: The MN sends an RRC reconfiguration message to the terminal device. The method according to claim 22 or 23 is characterized in that, The fifth instruction information indicates at least one of the following: Changes between MCG and SCG bearers; Changes between MCG bearers and split bearers; Changes between SCG bearer and split bearer; Changes between the primary network device MN terminal bearer and the secondary network device SN terminal bearer. A communication processing method, applied to a second main network device, characterized in that, The method includes: Receive a Layer 1 / Layer 2 triggered mobility LTM handover request from the first primary network device; Send an LTM handover request response to the first primary network device, the LTM handover request response including pre-configuration information; Determine the processing strategy for the secondary cell group (SCG) configuration in LTM, the processing strategy including retaining or releasing the SCG configuration; Based on the processing policy configured in the SCG, an SN add request or a terminal device context release request is sent to the secondary network device SN. The method according to claim 25, characterized in that, The pre-configuration information includes bearer type configuration, and the bearer class includes at least one of the following: The main cell group's MCG bearer; SCG bearer in auxiliary cell group; Split the load. The method according to claim 25, characterized in that, The processing policy of the SCG configuration is determined based on first processing information received from the first primary network device, which is used to indicate the processing policy of the SCG configuration in the LTM. The method according to claim 27, characterized in that, The first processing information is transmitted via the Xn interface. The method according to claim 25, characterized in that, The processing policy configured in the SCG is either pre-configured or determined in response to an LTM handover request received from the first primary network device. The step of sending an SN add request or a terminal device context release request to the secondary network device SN based on the processing policy configured in the SCG includes: Receive second indication information from the first main network device, the second indication information being used to indicate the target cell for handover; Based on the processing strategy configured in the SCG and the second indication information, an SN add request or a terminal device context release request is sent to the SN. The method according to any one of claims 25-29, characterized in that, The method further includes: Send a third indication message to the SN, the third indication message being used to indicate that the SN configuration should be updated. The method according to claim 30, characterized in that, The third indication information indicates at least one of the following: Changes between MCG and SCG bearers; Changes between MCG bearers and split bearers; Changes between SCG bearer and split bearer; Changes between the primary network device MN terminal bearer and the secondary network device SN terminal bearer. The method according to any one of claims 25-29, characterized in that, The method further includes: Send a fourth indication message, which is used to indicate the status information of the SCG configuration after LTM. A communication device, characterized in that, It includes a unit for performing the method as described in any one of claims 1-9, or a unit for performing the method as described in any one of claims 10-24, or a unit for performing the method as described in any one of claims 25-32. A communication device, characterized in that, It includes a processor and a memory, the processor and the memory being coupled, the processor being configured to implement the method as described in any one of claims 1-9, or the processor being configured to implement the method as described in any one of claims 10-24, or the processor being configured to implement the method as described in any one of claims 25-32. A chip characterized in that, The device includes a processor and an interface, the processor and the interface being coupled; the interface is used to receive or output signals, and the processor is used to execute code instructions to cause the method of any one of claims 1-9 to be executed, or to cause the method of any one of claims 10-24 to be executed, or to cause the method of any one of claims 25-32 to be executed. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when invoked by the computer, cause the computer to perform the method of any one of claims 1-9, or the method of any one of claims 10-24, or the method of any one of claims 25-32.

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