Handover method, communication device and communication system

Abstract

This application discloses a handover method, communication device, and communication system, relating to the field of communications, for reducing the activation latency of secondary cells during LTM handover. The method includes: receiving configuration information; the configuration information is used to configure a terminal device to perform synchronization, measurement, and transmission on at least one candidate primary cell and associated candidate secondary cells; performing measurements on at least one candidate primary cell and candidate secondary cells according to the configuration information, and sending a measurement report including measurement results of at least one candidate primary cell and measurement results of candidate secondary cells associated with the candidate primary cell; receiving a handover command; the handover command includes a target primary cell identifier and at least one of the following: secondary cell activation information and synchronization validity information; the secondary cell activation information is used to indicate the activated candidate secondary cell, and the synchronization validity information is used to indicate whether the synchronization information of the target primary cell is valid in the candidate secondary cell; and handing over to the target primary cell and activating the candidate secondary cell according to the handover command.

Description

Technical Field

[0001] This application relates to the field of communications, and more particularly to a switching method, a communication device, and a communication system. Background Technology

[0002] In the new radio (NR) interface of fifth-generation mobile communication systems, low-layer triggered mobility (L1 / L2-triggered mobility, LTM) technology significantly reduces cell handover interruption latency by decoupling the handover preparation phase from the execution phase.

[0003] However, in carrier aggregation (CA) scenarios, after a terminal device completes an LTM handover from the source primary cell to the target primary cell, in order to restore the high-speed transmission of carrier aggregation, the secondary cell originally associated with the source primary cell also needs to be released, and a new secondary cell associated with the target primary cell needs to be reactivated. If the traditional secondary cell activation process is followed, the network device needs to send an activation command to activate the secondary cell, which increases activation latency. Furthermore, if the terminal device indiscriminately uses synchronization information obtained before the handover (such as the timing advance (TA) value) to attempt synchronization in the new secondary cell, activation may fail, also increasing activation latency. These additional activation delays offset the gains from LTM handover, resulting in a still relatively long interruption time for user plane data transmission. Summary of the Invention

[0004] This application provides a handover method, communication device, and communication system for reducing the activation delay of secondary cells during LTM handover.

[0005] To achieve the above objectives, the embodiments of this application adopt the following technical solutions: A first aspect provides a handover method applied to a terminal device. The method includes: receiving configuration information; the configuration information configuring the terminal device to perform synchronization, measurement, and transmission on at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell. Performing measurements on the at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell according to the configuration information, and sending a measurement report, the measurement report including measurement results of at least one candidate primary cell and measurement results of the candidate secondary cells associated with the candidate primary cell. Receiving a handover command; the handover command includes a target primary cell identifier and at least one of the following: secondary cell activation information and synchronization validity information; the secondary cell activation information indicates the activated target secondary cell associated with the target primary cell, and the synchronization validity information indicates whether the synchronization information (e.g., TA value, SSB) of the target primary cell is valid in the associated candidate secondary cell. Handing over to the target primary cell and activating the candidate secondary cell according to the handover command.

[0006] The handover method provided in this application involves a terminal device performing measurements on at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell based on received configuration information. The measurement results of the candidate primary cell and the candidate secondary cells associated with it are reported together in the measurement report. This allows the network device to comprehensively evaluate the signal quality of the primary and secondary cells, thereby determining the target primary cell that the terminal device needs to hand over to, and the target secondary cell associated with the target primary cell that needs to be activated. A handover command is then sent to the terminal device. The handover command includes not only the target primary cell identifier but may also include at least one of secondary cell activation information and synchronization validity information. The secondary cell activation information indicates the activated target secondary cell associated with the target primary cell, and the synchronization validity information indicates whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell. On the one hand, by merging the activation of the secondary cell and the handover of the primary cell under the same handover command, the serial delay of handover followed by activation in traditional schemes is avoided, achieving simultaneous handover of primary and secondary cells. On the other hand, through the synchronization validity information, the terminal device can directly reuse the primary cell's TA value to achieve zero-additional-delay activation when the synchronization information is valid. This reduces the activation latency of secondary cells during LTM handover while ensuring activation success rate, thus balancing activation efficiency and reliability.

[0007] In one possible implementation, the configuration information includes at least one of the following: candidate primary cell configuration, candidate secondary cell configuration, and association configuration; the candidate primary cell configuration is used to configure the terminal device to perform synchronization, measurement, and transmission on at least one candidate primary cell, and the candidate secondary cell configuration is used to configure the terminal device to perform synchronization, measurement, and transmission on candidate secondary cells; the candidate secondary cell configuration includes common configurations of candidate secondary cells; and the association configuration is used to indicate the common configurations of candidate secondary cells associated with the candidate primary cell in the candidate secondary cell configuration.

[0008] This avoids signaling redundancy caused by repeatedly configuring the same secondary cell information for each candidate primary cell, while ensuring that the terminal device can accurately know the secondary cell associated with each candidate primary cell. This lays the configuration foundation for subsequent joint measurement reporting and primary-secondary cell handover, reducing signaling overhead while improving configuration flexibility.

[0009] In one possible implementation, the candidate secondary cell configuration further includes a common configuration identifier corresponding to the common configuration of the candidate secondary cell; each entry in the associated configuration includes at least one of the following: a common configuration identifier, used to indicate the common configuration of the candidate secondary cell associated with the candidate primary cell in the candidate secondary cell configuration; and an overriding field, used to overridden the default value in the common configuration of the candidate secondary cell associated with the candidate primary cell.

[0010] Terminal devices can quickly index the corresponding public configuration through public configuration identifiers, and simultaneously make differentiated adjustments to the default values ​​in the public configuration based on the overlay field. This design enables the configuration of the same secondary cell to be shared and reused by multiple candidate primary cells, and supports the personalized configuration requirements of different primary cells for the same secondary cell through the overlay field. This reduces configuration redundancy, ensures configuration flexibility, and avoids the problem of being unable to adapt to the differentiated needs of different primary cells due to fixed configurations.

[0011] In one possible implementation, the coverage field includes at least one of the following: a third synchronization signal block (SSB) configuration for covering the second SSB configuration in the common configuration of the candidate secondary cell; a third transmission configuration indicating TCI state for covering the second TCI state in the common configuration of the candidate secondary cell; a third reference signal configuration for covering the second reference signal configuration in the common configuration of the candidate secondary cell; the SSB configuration indicating parameters of the SSB used by the terminal device to perform synchronization, the TCI state indicating the beam used by the terminal device to receive signals, and the reference signal configuration indicating parameters of the reference signal used by the terminal device to measure the cell signal quality.

[0012] When activating a secondary cell, the terminal device can adopt differentiated synchronization parameters, beam parameters, and measurement parameters based on the currently associated primary cell. Specifically, the SSB configuration indicates the SSB parameters used by the terminal device to perform synchronization, the TCI status indicates the beam direction used to receive the signal, and the reference signal configuration indicates the reference signal parameters used to measure the signal quality of the cell. Through the flexible configuration of these three coverage fields, fine-grained parameter adjustments at the primary cell level are achieved, further enhancing the configuration adaptation capability in scenarios where multiple primary cells share the same secondary cell.

[0013] In one possible implementation, all entries in the associated configuration are arranged in descending order of the activation priority of the secondary cell.

[0014] Terminal devices and network devices can implicitly know the priority order of each candidate secondary cell without additional signaling interaction. This ordered arrangement provides a unified benchmark for subsequent indication of the order of secondary cell activation, measurement result reporting, and secondary cell activation. Terminal devices can directly perform measurement reporting and activation operations according to the order in the associated configuration without carrying additional priority indication information, thereby saving signaling overhead and simplifying the processing logic of terminal devices and network devices.

[0015] In one possible implementation, the secondary cell activation information is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the target primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. The i-th bit is a first value, indicating that the corresponding candidate secondary cell is not activated; the i-th bit is a second value, indicating that the corresponding candidate secondary cell is activated.

[0016] This bitmap indication method can indicate the activation status of multiple candidate secondary cells with minimal signaling overhead. Compared with listing candidate secondary cell identifiers one by one, it significantly reduces the payload of handover commands. At the same time, the implicit correspondence between the bitmap and the associated configuration order allows the terminal device to quickly determine the candidate secondary cells to be activated without parsing additional identifier information, thus reducing the processing latency of handover commands.

[0017] In one possible implementation, the synchronization validity information is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the target primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. The i-th bit is a first value, indicating that the synchronization information of the target primary cell is invalid in the associated i-th candidate secondary cell; the i-th bit is a second value, indicating that the synchronization information of the target primary cell is valid in the associated i-th candidate secondary cell.

[0018] This synchronization validity indication mechanism enables terminal devices to distinguish the synchronization information status of different secondary cells when activating them: for secondary cells with a valid validity indication, the terminal device can directly reuse the synchronization information of the primary cell (e.g., TA value and SSB), achieving activation with zero additional latency. For secondary cells with an invalid validity indication, the terminal device verifies the validity of the target primary cell's synchronization information and then uses that information; alternatively, it may backtrack and search for the SSB of candidate secondary cells to avoid activation failure due to the use of outdated synchronization information. This mechanism maximizes rapid activation while ensuring a high activation success rate, balancing efficiency and reliability.

[0019] In one possible implementation, the measurement results of candidate secondary cells are arranged in descending order of the activation priority of the secondary cells.

[0020] By arranging the measurement results of candidate secondary cells in descending order of their activation priority, the order of candidate secondary cell measurement results in the measurement report is strictly aligned with the order of candidate secondary cells in the associated configuration. This order alignment design allows network devices to associate measurement results with corresponding candidate secondary cells simply by their sequential position, without needing to carry candidate secondary cell identifiers for each measurement result when parsing the measurement report. This significantly reduces the signaling overhead of the measurement report.

[0021] In one possible implementation, the measurement report further includes measurement result validity information, which indicates the candidate secondary cells with valid measurement results among all candidate secondary cells associated with the target primary cell; the measurement results of the candidate secondary cells associated with the candidate primary cell in the measurement report indicate the measurement results of the valid candidate secondary cells indicated by the measurement result validity information.

[0022] By incorporating measurement result validity information into the measurement report, this scheme indicates which candidate secondary cells among all candidate secondary cells associated with the target primary cell have valid measurement results. The measurement report only includes measurement results from the valid secondary cells indicated by the validity information. Compared to the method of reporting measurement results from all associated secondary cells, this scheme avoids reporting invalid measurement data when some secondary cells have poor signal quality or unavailable measurement results. This reduces the payload size of the measurement report and decreases uplink signaling resource consumption. Furthermore, network devices only need to parse valid measurement results to make activation decisions, eliminating the need to process invalid data and improving network device processing efficiency.

[0023] In one possible implementation, the validity information of the measurement result is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the candidate primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. The i-th bit is a first value, indicating that the measurement result of the i-th candidate secondary cell is invalid; the i-th bit is a second value, indicating that the measurement result of the i-th candidate secondary cell is valid.

[0024] This bitmap indication method can provide a complete indication of the validity of measurement results for multiple candidate secondary cells with minimal signaling overhead. The terminal device uses this bitmap to determine which secondary cell measurement results should be included in the measurement report, and the network device uses the bitmap to determine the correspondence between each measurement result in the measurement report and the candidate secondary cells. This scheme achieves variable-length measurement reports while maintaining compatibility with fixed-order alignment mechanisms, balancing signaling efficiency and deterministic parsing.

[0025] Secondly, a handover method is provided, applied to a network device. The method includes: sending configuration information; the configuration information is used to configure a terminal device to perform synchronization, measurement, and transmission on at least one candidate primary cell and a candidate secondary cell associated with the candidate primary cell; receiving a measurement report, the measurement report including measurement results of at least one candidate primary cell and measurement results of the candidate secondary cell associated with the candidate primary cell; sending a handover command; the handover command includes a target primary cell identifier and at least one of the following: secondary cell activation information and synchronization validity information; the secondary cell activation information is used to indicate the activated target secondary cell associated with the target primary cell, and the synchronization validity information is used to indicate whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell; the handover command is used to trigger the terminal device to handover to the target primary cell and activate the candidate secondary cell.

[0026] In one possible implementation, the configuration information includes at least one of the following: candidate primary cell configuration, candidate secondary cell configuration, and association configuration; the candidate primary cell configuration is used to configure the terminal device to perform synchronization, measurement, and transmission on at least one candidate primary cell, and the candidate secondary cell configuration is used to configure the terminal device to perform synchronization, measurement, and transmission on candidate secondary cells; the candidate secondary cell configuration includes common configurations of candidate secondary cells; and the association configuration is used to indicate the common configurations of candidate secondary cells associated with the candidate primary cell in the candidate secondary cell configuration.

[0027] In one possible implementation, the candidate secondary cell configuration further includes a common configuration identifier corresponding to the common configuration of the candidate secondary cell; each entry in the associated configuration includes at least one of the following: a common configuration identifier, used to indicate the common configuration of the candidate secondary cell associated with the candidate primary cell in the candidate secondary cell configuration; and an overriding field, used to overridden the default value in the common configuration of the candidate secondary cell associated with the candidate primary cell.

[0028] In one possible implementation, the coverage field includes at least one of the following: a third synchronization signal block (SSB) configuration for covering the second SSB configuration in the common configuration of the candidate secondary cell; a third transmission configuration indicating TCI state for covering the second TCI state in the common configuration of the candidate secondary cell; a third reference signal configuration for covering the second reference signal configuration in the common configuration of the candidate secondary cell; the SSB configuration indicating parameters of the SSB used by the terminal device to perform synchronization, the TCI state indicating the beam used by the terminal device to receive signals, and the reference signal configuration indicating parameters of the reference signal used by the terminal device to measure the cell signal quality.

[0029] In one possible implementation, all entries in the associated configuration are arranged in descending order of the activation priority of the secondary cell.

[0030] In one possible implementation, the secondary cell activation information is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the target primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. The i-th bit is a first value, indicating that the corresponding candidate secondary cell is not activated; the i-th bit is a second value, indicating that the corresponding candidate secondary cell is activated.

[0031] In one possible implementation, the synchronization validity information is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the target primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. The i-th bit is a first value, indicating that the synchronization information of the target primary cell is invalid in the associated i-th candidate secondary cell; the i-th bit is a second value, indicating that the synchronization information of the target primary cell is valid in the associated i-th candidate secondary cell.

[0032] In one possible implementation, the measurement results of candidate secondary cells are arranged in descending order of the activation priority of the secondary cells.

[0033] In one possible implementation, the measurement report further includes measurement result validity information, which indicates the candidate secondary cells with valid measurement results among all candidate secondary cells associated with the target primary cell; the measurement results of the candidate secondary cells associated with the candidate primary cell in the measurement report indicate the measurement results of the valid candidate secondary cells indicated by the measurement result validity information.

[0034] In one possible implementation, the validity information of the measurement result is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the candidate primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. The i-th bit is a first value, indicating that the measurement result of the i-th candidate secondary cell is invalid; the i-th bit is a second value, indicating that the measurement result of the i-th candidate secondary cell is valid.

[0035] Thirdly, a communication device is provided, comprising a processing module and a communication module. The communication module is configured to receive configuration information; the configuration information is configured to configure a terminal device to perform synchronization, measurement, and transmission on at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell; perform measurements on at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell according to the configuration information, and send a measurement report, the measurement report including measurement results of at least one candidate primary cell and measurement results of candidate secondary cells associated with the candidate primary cell; and receive a handover command; the handover command includes a target primary cell identifier and at least one of the following: secondary cell activation information and synchronization validity information; the secondary cell activation information is used to indicate the activated target secondary cell associated with the target primary cell, and the synchronization validity information is used to indicate whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell. The processing module is configured to handover to the target primary cell and activate the candidate secondary cell according to the handover command.

[0036] Fourthly, a communication device is provided, comprising a processing module and a communication module. The communication module is used to send configuration information; the configuration information is used to configure a terminal device to perform synchronization, measurement, and transmission on at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell; receive a measurement report, the measurement report including measurement results of at least one candidate primary cell and measurement results of candidate secondary cells associated with the candidate primary cell; send a handover command; the handover command includes a target primary cell identifier and at least one of the following: secondary cell activation information and synchronization validity information; the secondary cell activation information is used to indicate the activated target secondary cell associated with the target primary cell, and the synchronization validity information is used to indicate whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell; the handover command is used to trigger the terminal device to hand over to the target primary cell and activate the candidate secondary cell.

[0037] Fifthly, a communication device is provided, including a processor. The processor is coupled to a memory and can be used to execute instructions or data in the memory to implement the methods described in the first aspect and any possible implementation thereof. Optionally, the communication device may further include a memory. Optionally, the communication device may further include a communication interface, and the processor is coupled to the communication interface.

[0038] In one implementation, the communication interface can be a transceiver, or an input / output interface.

[0039] In another implementation, the communication device is a chip configured in a terminal device. When the communication device is a chip configured in a terminal device, the communication interface can be an input / output interface.

[0040] Sixthly, a communication device is provided, including a processor. The processor is coupled to a memory and can be used to execute instructions or data in the memory to implement the methods described in the second aspect and any possible implementation thereof. Optionally, the communication device may further include a memory. Optionally, the communication device may further include a communication interface, and the processor is coupled to the communication interface.

[0041] In one implementation, the communication interface can be a transceiver, or an input / output interface.

[0042] In another implementation, the communication device is a chip configured in a network device. When the communication device is a chip configured in a network device, the communication interface can be an input / output interface.

[0043] A seventh aspect provides a processor, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is configured to receive signals through the input circuit and transmit signals through the output circuit, causing the processor to execute the methods described in the first aspect, the second aspect, and any possible implementation thereof.

[0044] In specific implementation, the processor can be one or more chips, the input circuit can be input pins, the output circuit can be output pins, and the processing circuit can be transistors, gate circuits, flip-flops, and various logic circuits. The input signal received by the input circuit can be received and input by, for example, but not limited to, a receiver, and the signal output by the output circuit can be, for example, but not limited to, output to and transmitted by a transmitter. Furthermore, the input circuit and the output circuit can be the same circuit, which is used as both the input circuit and the output circuit at different times. This application does not limit the specific implementation of the processor and various circuits.

[0045] Eighthly, a communication device is provided, including a processor and a memory. The processor is configured to read instructions stored in the memory, receive signals via a receiver, and transmit signals via a transmitter to execute the methods described in the first aspect and any possible implementation thereof.

[0046] Optionally, the processor may be one or more, and the memory may be one or more.

[0047] A ninth aspect provides a communication device including a processor and a memory. The processor is configured to read instructions stored in the memory, receive signals via a receiver, and transmit signals via a transmitter to execute the methods described in the second aspect and any possible implementation thereof.

[0048] Optionally, the processor may be one or more, and the memory may be one or more.

[0049] In a tenth aspect, a computer program product is provided, the computer program product comprising: a computer program (also referred to as code or instructions) that, when the computer program is run, causes a computer to perform the methods described in the first to second aspects and any possible implementation thereof.

[0050] Eleventhly, a computer-readable storage medium is provided that stores a computer program (also referred to as code or instructions) that, when run on a computer, causes the computer to perform the methods described in the first to second aspects and any possible implementation thereof.

[0051] In a twelfth aspect, embodiments of this application provide a chip system including one or more processors for calling and executing instructions stored in memory, causing the methods described in the first aspect, the second aspect, and any possible implementation to be executed. The chip system may be composed of chips or may include chips and other discrete devices.

[0052] The chip system may include input circuits or interfaces for transmitting information or data, and output circuits or interfaces for receiving information or data.

[0053] In a thirteenth aspect, a communication system is provided, including the aforementioned communication device. Optionally, the communication system may further include other devices that communicate with the communication device. Alternatively, it may include a terminal device and a network device, wherein the terminal device is configured to perform the method as described in the first aspect and any embodiment thereof, and the network device is configured to perform the method as described in the second aspect and any embodiment thereof.

[0054] The technical effects of the second to thirteenth aspects refer to the technical effects of the first aspect and any of its embodiments, and will not be repeated here. Attached Figure Description

[0055] Figure 1 This application provides a schematic diagram of the architecture of a wireless communication system. Figure 2 A schematic diagram of an LTM technology provided in an embodiment of this application; Figure 3 A flowchart illustrating a switching method provided in an embodiment of this application; Figure 4 A schematic diagram illustrating the relationship between associated configuration and candidate secondary cell configuration provided in an embodiment of this application; Figure 5 A schematic diagram of a MAC CE for a Layer 1 measurement report provided in an embodiment of this application; Figure 6A schematic diagram of another Layer 1 measurement report MAC CE provided for an embodiment of this application; Figure 7 A schematic diagram of a MAC CE for a switching command provided in an embodiment of this application; Figure 8 A flowchart illustrating another switching method provided in an embodiment of this application; Figure 9 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application; Figure 10 This is a schematic diagram of another communication device provided in an embodiment of this application. Detailed Implementation

[0056] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0057] First, some concepts involved in this application will be described.

[0058] The terms "first" and "second" used in the embodiments of this application are only used to distinguish features of the same type and should not be construed as indicating relative importance, quantity, order, etc.

[0059] The terms "exemplary" or "for example" used in the embodiments of this application are used to indicate examples, illustrations, or descriptions. Any embodiment 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 embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0060] The technical solutions provided in this application can be used in any communication system, such as 3GPP communication systems, including radio frequency identification (RFID) systems, long-term evolution (LTE) systems, fifth-generation (5G) mobile communication systems, new radio (NR) communication systems, vehicle-to-everything (V2X) systems, and systems that combine LTE and 5G networks. They can also be applied to non-terrestrial network (NTN) systems, device-to-device (D2D) communication systems, machine-to-machine (M2M) communication systems, Internet of Things (IoT) systems, ambient IoT (A-IoT) systems, universal mobile telecommunications systems (UMTS) systems, code division multiple access (CDMA) systems, and other next-generation communication systems, such as 6G and other future communication systems. Alternatively, they can be non-3GPP communication systems, such as wireless local area networks (WLANs). (network, WLAN, etc.) are not limited.

[0061] Figure 1 This is a schematic diagram of the architecture of a wireless communication system provided in an embodiment of this application. The communication system 100 may include network devices, such as... Figure 1 At least one network device 110 is shown. The communication system 100 may also include terminal devices, such as... Figure 1 The terminal device 120 shown. The network device 110 and the terminal device 120 can communicate with each other via a wireless link.

[0062] Figure 1 An exemplary network device 110 and a terminal device 120 are shown. Optionally, the communication system 100 may also include multiple network devices 110 and multiple terminal devices 120.

[0063] In this application, the terminal device can refer to user equipment (UE), station, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device. The terminal device can also be a cellular phone, cordless phone, session initiation protocol (SIP) phone, wire local loop (WLL) station, personal digital assistant (PDA), handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, large screen, in-vehicle device, wearable device, terminal device in a 5G network, or terminal device in a future public land mobile network (PLMN), etc. This application does not limit the scope of the terminal device.

[0064] In this application, the apparatus for implementing the functions of the terminal device can be the terminal device itself, or any apparatus capable of supporting the terminal device in implementing those functions, such as a processor, circuit, or chip system. This apparatus can be installed in or connected to the terminal device. In the technical solutions provided in this application, the example of a terminal device being used to implement the functions of the terminal device is used to describe the technical solutions provided in this application.

[0065] The network equipment in this application can be network-side equipment such as access network and core network equipment. Access network equipment is sometimes also called access point. Access network equipment has wireless transceiver capabilities and is used to communicate with terminals. Access network equipment includes, but is not limited to, base stations, evolved NodeBs (eNodeBs), transmission reception points (TRPs) in the above-mentioned communication systems, next-generation NodeBs (gNBs) in 5G mobile communication systems, aNBs in 6G mobile communication systems, access network equipment or modules of access network equipment in open RAN (ORAN) systems, satellites in NTN communication systems, base stations in future mobile communication systems, or access nodes in WiFi systems. Access network equipment can also be modules or units capable of implementing some of the functions of a base station. Access network equipment can be macro base stations, micro base stations or indoor stations, relay nodes or donor nodes, or wireless controllers in cloud radio access network (CRAN) scenarios. Optionally, access network equipment can also be servers, wearable devices, or vehicle-mounted equipment, etc. For example, the access network equipment in vehicle-to-everything (V2X) technology can be a roadside unit (RSU). Multiple access network devices in a communication system can be base stations of the same type or different types. Base stations can communicate directly with terminals or via relay stations. Terminals can communicate with multiple base stations using different access technologies. This application does not limit the specific technology or equipment form used in the access network equipment.

[0066] In this application, the means for implementing the functions of a network device can be a network device itself, or a means capable of supporting the network device in implementing those functions, such as a processor, circuit, chip, or chip system. This means can be installed in the network device or connected to the network device for use. In the technical solutions provided in this application, the example of a network device being used to implement the functions of a network device is used to describe the technical solutions provided in this application.

[0067] Network devices and terminal devices can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can be deployed in the air on airplanes, balloons, and artificial satellites. This application does not limit the application scenarios of network devices and terminal devices. Network devices and terminal devices can be deployed in the same or different scenarios. For example, network devices and terminal devices can be deployed simultaneously on land; or, network devices can be deployed on land and terminal devices can be deployed on water, etc., and so on.

[0068] It is understood that the communication systems and scenarios applicable to this application described above are merely illustrative examples, and the communication systems applicable to this application are not limited thereto. This will be explained uniformly here and will not be repeated below.

[0069] In practical applications, multiple network devices can collaborate to assist terminals in achieving wireless access, with different network devices each implementing a portion of the base station's functions. For example, network devices can be central units (CUs), distributed units (DUs), CUs (control planes, CPs), CUs (user planes, UPs), or radio units (RUs), etc. CUs and DUs can be set up separately or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio frequency equipment or radio frequency units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs).

[0070] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (Open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules. CU (or CU-CP and CU-UP), DU, and RU can implement different protocol layer functions.

[0071] The system described in this application is intended to more clearly illustrate the technical solutions of this application, and does not constitute a limitation on the technical solutions provided in this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in this application are also applicable to similar technical problems.

[0072] In the following embodiments of this application, the message names, parameter names, or information names between the terminal device and the network device are just examples. Other names may be used in other embodiments, and the method provided in this application does not specifically limit them.

[0073] It is hereby uniformly stated that in the interaction process of the embodiments of this application, the message or signaling interaction involved can adopt the message or signaling in the NR standard, or it can be a newly introduced message or signaling. The embodiments of this application do not make specific limitations on this.

[0074] It is understood that in the embodiments of this application, each communication device may execute some or all of the steps in the embodiments of this application. These steps or operations are merely examples, and the embodiments of this application may also execute other operations or variations thereof. Furthermore, the steps may be executed in different orders as presented in the embodiments of this application, and it is not necessary to execute all the operations in the embodiments of this application.

[0075] It is understood that this application uses terminal devices and network devices as examples to illustrate the execution of the interaction, but this application does not limit the execution subject of the interaction. For example, the method executed by the terminal device in this application can also be executed by a module applied to the terminal device (e.g., a chip, chip system, or processor), or by a logical node, logical module, or software that can implement all or part of the functions of the terminal device; similarly, the method executed by the network device in this application can also be executed by a module applied to the network device (e.g., a chip, chip system, or processor), or by a logical node, logical module, or software that can implement all or part of the functions of the network device.

[0076] To facilitate understanding of the embodiments of this application, the terminology used in the embodiments is first briefly explained. Optionally, the explanation of some terms can also refer to the explanations in the 3rd Generation Partnership Project (3GPP) standard protocol. It should be understood that the technical terminology in the embodiments of this application is only illustrative and not limiting. For example, as technology evolves, technical terminology may also change; where the technical meaning remains the same, other technical terms should also apply to this application.

[0077] L1 / L2 triggered mobility (LTM) and carrier aggregation (CA): In the new radio (NR) interface of fifth-generation mobile communication systems, CA is a key technology that allows terminal devices to simultaneously connect to a service primary cell (SpCell) and one or more secondary cells (SCells), thereby aggregating the resources of multiple carrier units to provide the terminal device with greater transmission bandwidth and higher data rates. The primary cell is used for control plane connectivity and mobility management, while the secondary cells are used for user plane data transmission.

[0078] Traditional handover procedures, such as handover based on radio resource control (RRC) reconfiguration, suffer from significant interruption latency, typically reaching tens of milliseconds. This is unacceptable for latency-sensitive services such as ultra-reliable and low-latency communication (URLLC) and extended reality (XR). To reduce handover interruption latency to near-zero millisecond levels, communication protocols have introduced LTM (Last Time Timing) technology.

[0079] Figure 2 This diagram illustrates an LTM (Laser-Terminal Messaging) technology provided in an embodiment of this application. The core idea of ​​LTM technology is to decouple the handover preparation phase from the execution phase. The network device pre-configures a set of candidate service primary cells (Candidate SpCells) 1101 for the terminal device 120 via Radio Resource Control (RRC) signaling. The terminal device 120 performs Layer 1 (L1) measurements on these cells and reports them. When the handover conditions are met, the network device only needs to issue a lightweight Layer 1 / Layer 2 (L1 / L2) signaling message, such as a Media Access Control (MAC) CE or Downlink Control Information (DCI), allowing the terminal device to immediately hand over from the source primary cell 1102 to the target primary cell 1103 without undergoing a complete RRC reconfiguration process. This significantly reduces the handover execution latency.

[0080] Although LTM technology effectively reduces the handover interruption latency of the primary cell, the activation latency of the secondary cell becomes a new bottleneck in CA scenarios.

[0081] After LTM handover is completed, the service bearer of the terminal equipment needs to be migrated from the source primary cell to the target primary cell. Simultaneously, to restore high-speed transmission via carrier aggregation, the secondary cell originally associated with the source primary cell also needs to be released, and a new secondary cell associated with the target primary cell needs to be reactivated. If the traditional secondary cell activation process is followed, the network equipment needs to send activation commands to activate the secondary cell, which increases activation latency.

[0082] Furthermore, during the measurement phase, to evaluate the signal quality of candidate secondary cells, terminal equipment needs to first perform downlink synchronization in the candidate secondary cells, i.e., search for the optimal SSB index and determine the corresponding receive beam. However, there is a significant time delay between the terminal equipment completing measurement reporting and the network equipment making a decision and issuing a handover command. During this time, the terminal equipment may have moved, the previously measured optimal SSB index and receive beam may no longer be accurate, and the optimal SSB may have become very weak or even disappeared. If the terminal equipment indiscriminately uses the SSB information obtained before the handover to attempt synchronization in the new secondary cell, it may lead to activation failure, which will also increase the activation delay.

[0083] These additional activation delays significantly offset the gains from the rapid handover of LTM primary cells, resulting in a still relatively long interruption time for user plane data transmission.

[0084] To address this, this application provides a handover method in which the terminal device reports the measurement results of the candidate primary cell and the candidate secondary cell associated with it in the measurement report. This allows the network device to comprehensively evaluate the signal quality of the primary and secondary cells, thereby determining the target primary cell that the terminal device needs to hand over to, and the target secondary cell associated with the target primary cell that needs to be activated. The handover command sent by the network device to the terminal device includes not only the target primary cell identifier but may also include at least one of secondary cell activation information and synchronization validity information. The secondary cell activation information indicates the activated target secondary cell associated with the target primary cell, and the synchronization validity information indicates whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell. On the one hand, by merging the activation of the secondary cell and the handover of the primary cell into a single handover command, the serial delay of handover followed by activation in traditional schemes is avoided, achieving simultaneous handover of primary and secondary cells. On the other hand, through the synchronization validity information, the terminal device can directly reuse the primary cell's TA value to achieve zero-additional-delay activation when the synchronization information is valid. Thus, while ensuring the activation success rate, the activation delay of the secondary cell during the LTM handover process is reduced.

[0085] The following section, in conjunction with the corresponding flowchart, provides a detailed explanation of the solution provided in this application.

[0086] Figure 3This is a flowchart illustrating a switching method provided in an embodiment of this application. It can be understood that the terminal device involved in this switching method can be... Figure 1 The terminal device 120 mentioned can also refer to a device within the terminal device 120 (such as a processor, chip, or chip system). The network equipment involved in this handover method can be... Figure 1 The term "network device 110" can also refer to devices within the network device 110 (such as processors, chips, or chip systems).

[0087] like Figure 3 As shown, the switching method 300 includes the following steps S101-S105: S101. The network device sends configuration information to the terminal device.

[0088] Network devices can send LTM-related configuration information to terminal devices via RRC Reconfiguration messages. The terminal devices then receive this configuration information. This configuration information is used to configure the terminal devices to perform synchronization, measurement, and transmission on at least one candidate primary cell and its associated candidate secondary cells. The configuration information includes at least one of the following: candidate primary cell configuration, candidate secondary cell common configuration, and association configuration.

[0089] Candidate primary cells are a set of primary cells that network devices pre-configure for terminal devices via RRC signaling, which can serve as targets for handover and camping. In LTM handover scenarios, when the signal quality of the terminal device's primary cell deteriorates, or when the signal quality of a candidate primary cell meets the handover conditions, the network device can quickly trigger the terminal device to handover to that candidate primary cell without undergoing a complete RRC reconfiguration process. For example, the network device pre-configures candidate primary cell 1 and candidate primary cell 2 for the terminal device. When the terminal device hands over from candidate primary cell 1 to candidate primary cell 2, the network device only needs to issue a lightweight MAC CE or DCI command, and the terminal device can immediately hand over to candidate primary cell 2.

[0090] A candidate secondary cell is a secondary cell that is jointly activated with the target primary cell during LTM handover. Unlike traditional secondary cells, candidate secondary cells are characterized by being pre-configured to the terminal device via RRC signaling before the handover occurs. The same candidate secondary cell can be associated with multiple candidate primary cells, uses independent numbering resources, such as a common configuration identifier (CandidateSCellCommonConfigId), and does not occupy the numbering resources of the candidate primary cell.

[0091] The association between candidate primary cells and candidate secondary cells means that candidate primary cells and candidate secondary cells can be combined to form a CA cell. The candidate primary cell serves as the mounting point for the candidate secondary cell.

[0092] The candidate primary cell configuration can be in the form of a list or other formats, with each candidate primary cell configuration being a separate entry. The candidate primary cell configuration is used to configure the terminal device to perform synchronization, measurement, and transmission on at least one candidate primary cell. Specifically, the candidate primary cell configuration includes at least one of the following for the candidate primary cell: a first physical cell identifier (PCI), a first downlink frequency, a first bandwidth, a first synchronization signal block (SSB) configuration, a first reference signal configuration, and a first transmission configuration indicator (TCI) status.

[0093] PCI is used to uniquely identify a physical cell. The role of the first PCI in candidate primary cell configuration: Terminal devices need to know the first PCI of candidate primary cells in order to search for and identify candidate primary cells on the corresponding frequency points.

[0094] Downlink frequency and bandwidth define the frequency location and frequency range in which the secondary cell operates. Downlink frequency: also known as the absolute radio frequency channel number (ARFCN), it indicates the center frequency location of the cell's downlink transmission. The terminal device tunes to the corresponding frequency based on this frequency to receive signals. Bandwidth: refers to the frequency width occupied by the cell, measured in physical resource blocks (PRBs) or MHz. Bandwidth determines the maximum data transmission rate that the cell can provide. The role of the first downlink frequency and first bandwidth in candidate primary cell configuration: The terminal device needs to know the first downlink frequency and first bandwidth of the candidate primary cell to correctly tune the receiver and perform signal detection and data transmission within that frequency range.

[0095] The Subsidiary Synchronization Signal (SSB) is a crucial signal used for initial synchronization and cell search. Each SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The SSB configuration indicates the parameters of the SSB used by the terminal device to perform synchronization. The SSB configuration includes at least one of the following: SSB period, indicating the transmission interval of the SSB, typically 5ms, 10ms, 20ms, etc.; SSB frequency domain position, indicating the starting resource block (RB) position of the SSB in the carrier; SSB subcarrier spacing, indicating the subcarrier spacing used by the SSB, which can be 15kHz, 30kHz, 120kHz, or 240kHz, etc.; and SSB time domain position, indicating the transmission time position of the SSB within one period (in symbols). The role of the first SSB configuration in candidate primary cell configuration: The terminal device needs to know the SSB configuration of the candidate primary cell in order to search for the SSB at the corresponding time-frequency position and complete downlink synchronization with the candidate primary cell.

[0096] The reference signal configuration indicates the parameters of a reference signal (e.g., a channel state information reference signal (CSI-RS)) used by the terminal equipment to measure cell signal quality. The reference signal configuration includes at least one of the following: the time-frequency resource location of the reference signal, such as period, time slot offset, and resource block location; and the sequence configuration of the reference signal. The role of the first reference signal configuration in candidate primary cell configuration: The terminal equipment evaluates the signal quality of the candidate primary cell by measuring its reference signal, thus obtaining the measurement results of the candidate primary cell.

[0097] The measurement results involved in the embodiments of this application include at least one of the following: reference signal received power (RSRP), reference signal received quality (RSRQ), and signal to interference plus noise ratio (SINR).

[0098] The TCI state is used to indicate the beam used by a terminal device to receive signals. For example, if a network device configures the TCI state to point to a specific SSB index, it means that the terminal device should use the optimal receive beam for that SSB to receive the Physical Downlink Control Channel (PDCCH) or Physical Downlink Shared Channel (PDSCH). The role of the first TCI state in candidate primary cell configuration: After a terminal device hands over to a primary cell, it needs to use the first TCI state to determine which receive beam to use to receive the downlink control channel and data channel of that primary cell.

[0099] Candidate secondary cell configuration is used to configure terminal devices to perform synchronization, measurement, and transmission on candidate secondary cells. Candidate secondary cell configuration can be in the form of a list (CandidateSCellCommonConfigList) or other forms. Each entry includes the common configuration (CandidateSCellCommonConfig) of the candidate secondary cell and its corresponding common configuration identifier (CandidateSCellCommonConfigId). The common configuration of a candidate secondary cell refers to the configuration of the same candidate secondary cell associated with multiple candidate primary cells. That is, if the same candidate secondary cell is associated with multiple candidate primary cells, only one common configuration for that candidate secondary cell needs to be maintained.

[0100] Specifically, the common configuration of the candidate secondary cell includes at least one of the following: second PCI, second downlink frequency, second bandwidth, second SSB configuration, second reference signal configuration, and second TCI status. This information serves as the default value for the candidate secondary cell.

[0101] The role of the second PCI in the common configuration of candidate secondary cells: Terminal devices need to know the second PCI of candidate secondary cells in order to search for and identify candidate secondary cells on the corresponding frequency points.

[0102] The role of the second downlink frequency and the second bandwidth in the common configuration of candidate secondary cells: Terminal equipment needs to know the second downlink frequency and the second bandwidth of the candidate secondary cells in order to correctly tune the receiver and perform signal detection and data transmission within that frequency range.

[0103] The role of the second SSB configuration in the common configuration of candidate secondary cells: The terminal device needs to know the SSB configuration of the candidate secondary cell in order to search for the SSB at the corresponding time-frequency location and complete the downlink synchronization with the candidate secondary cell.

[0104] The role of the second reference signal configuration in the common configuration of candidate secondary cells: The terminal device evaluates the signal quality of the candidate secondary cell by measuring the reference signal of the candidate secondary cell and obtains the measurement result of the candidate secondary cell.

[0105] The role of the second TCI state in the common configuration of candidate secondary cells: After the terminal device activates a secondary cell, it needs to know which receive beam to use through the second TCI state to receive the downlink control channel and data channel of that secondary cell.

[0106] Network devices configure an association configuration for each candidate primary cell. This association configuration can be in the form of a list (associatedCandidateSCellInstanceList) or other forms. The association configuration indicates the common configuration of candidate secondary cells associated with the candidate primary cell in the candidate secondary cell configuration. When a terminal device switches to a candidate primary cell, these associated candidate secondary cells can be activated simultaneously to achieve "simultaneous primary and secondary cell handover." In other words, the candidate primary cell determines which candidate secondary cells can be activated. Candidate secondary cells not in the association configuration of the candidate primary cell are not within the activation scope of this handover. For example, the association configuration of candidate primary cell 1 is {secondary cell A, secondary cell B, secondary cell C}, and the association configuration of candidate primary cell 2 is {secondary cell A, secondary cell D, secondary cell E}. When the terminal device switches to candidate primary cell 1, the set of candidate secondary cells that can be activated is {secondary cell A, secondary cell B, secondary cell C}; when the terminal device switches to candidate primary cell 2, the set of candidate secondary cells that can be activated is {secondary cell A, secondary cell D, secondary cell E}. The same candidate secondary cell A is associated with multiple candidate primary cells (candidate primary cell 1 and candidate primary cell 2).

[0107] All entries in the associated configuration are arranged in descending order of secondary cell activation priority. The activation priority of secondary cells can be pre-configured by the network device, and this arrangement can also be used for subsequent measurement reporting and activation indication. Candidate secondary cells with higher activation priority are activated first, followed by those with lower priority. Terminal devices and network devices can implicitly know the priority order of each candidate secondary cell without additional signaling interaction. This ordered arrangement provides a unified benchmark for subsequent indications of the activation order of secondary cells, the measurement result reporting order, and the secondary cell activation order. Terminal devices can directly perform measurement reporting and activation operations according to the order in the associated configuration without carrying additional priority indication information, thus saving signaling overhead and simplifying the processing logic of terminal devices and network devices.

[0108] Each table entry in the association configuration includes at least one of the following: A common configuration identifier is used to indicate the common configuration of candidate secondary cells associated with the candidate primary cell in the candidate secondary cell configuration. When the common configuration identifier in the associated configuration of the candidate primary cell is the same as the common configuration identifier of a certain entry in the candidate secondary cell configuration, it indicates that the candidate primary cell is associated with the common configuration of the candidate secondary cell in that entry. Terminal devices can quickly index the corresponding common configuration through the common configuration identifier.

[0109] Coverage fields are used to override the default values ​​in the common configuration of candidate secondary cells associated with the candidate primary cell, enabling differentiated configuration. Coverage fields include at least one of the following: a third SSB configuration, used to override the second SSB configuration in the common configuration of the candidate secondary cell, thereby enabling different downlink synchronizations for the same candidate secondary cell; a third TCI state, used to override the second TCI state in the common configuration of the candidate secondary cell, to enable different beam configurations for the same candidate secondary cell; and a third reference signal configuration, used to override the second reference signal configuration in the common configuration of the candidate secondary cell, thereby meeting different measurement requirements for the same candidate secondary cell. When activating a secondary cell, the terminal device can adopt differentiated synchronization parameters, beam parameters, and measurement parameters based on the currently associated primary cell. Through the flexible configuration of these three types of coverage fields, fine-grained parameter adjustments at the primary cell level are achieved, further improving the configuration adaptation capability in scenarios where multiple primary cells share the same secondary cell.

[0110] For example, Figure 4 This is a schematic diagram illustrating the relationship between associated configuration and candidate secondary cell configuration provided in an embodiment of this application. The first entry in the associated configuration table is the associated configuration of candidate primary cell 1, including common configuration identifier 1, common configuration identifier 2, and coverage field 1. The second entry is the associated configuration of candidate primary cell 2, including common configuration identifier 1 and coverage field 2. The first entry in the candidate secondary cell configuration table includes common configuration identifier 1 and the common configuration of candidate secondary cell 1. The second entry includes common configuration identifier 2 and the common configuration of candidate secondary cell 2.

[0111] For candidate primary cell 1, since common configuration identifier 1 has no corresponding coverage field, when candidate primary cell 1 is associated with candidate secondary cell 1 (forming a CA cell), candidate secondary cell 1 adopts the common configuration of candidate secondary cell 1. Since common configuration identifier 2 has a corresponding coverage field 1, when candidate primary cell 1 is associated with candidate secondary cell 2 (forming a CA cell), candidate secondary cell 2 adopts coverage field 1 instead of its common configuration. For candidate primary cell 2, since common configuration identifier 1 has a corresponding coverage field 2, when candidate primary cell 2 is associated with candidate secondary cell 1 (forming a CA cell), candidate secondary cell 1 adopts coverage field 2 instead of its common configuration.

[0112] This hierarchical design allows the common configuration of the same candidate secondary cell to be reused by multiple candidate primary cells, and each candidate primary cell can be customized through overlay fields. This avoids signaling redundancy caused by repeatedly configuring the same secondary cell information for each candidate primary cell, while ensuring that terminal devices can accurately determine the secondary cells associated with each candidate primary cell. This lays the configuration foundation for subsequent joint measurement reporting and simultaneous primary / secondary cell handover, reducing signaling overhead while improving configuration flexibility.

[0113] S102. The terminal device performs measurements on at least one candidate primary cell and a candidate secondary cell associated with the candidate primary cell according to the configuration information, and sends a measurement report to the network device. The measurement report includes the measurement results of at least one candidate primary cell and the measurement results of the candidate secondary cell associated with the candidate primary cell.

[0114] The terminal device parses the candidate secondary cell configuration and establishes a public configuration list indexed by a public configuration identifier. If the same candidate secondary cell is associated with multiple candidate primary cells, only one public configuration for that candidate secondary cell needs to be maintained.

[0115] The terminal device parses the associated configuration, records the number of candidate secondary cells L associated with each candidate primary cell (i.e., the length of the associated configuration, or the number of candidate secondary cells that need to be configured) and the activation priority order, and stores the overlay field of each table entry.

[0116] The terminal device measures candidate secondary cells according to the configuration information and stores the measurement results. If the coverage field of a candidate secondary cell is not configured in the association configuration, the terminal device measures the candidate secondary cell according to the parameters in the common configuration of that candidate secondary cell, and obtains the measurement result of that candidate secondary cell. If the coverage field of a candidate secondary cell is configured in the association configuration, the terminal device overwrites the corresponding parameters in the common configuration of that candidate secondary cell according to the coverage field, and measures the candidate secondary cell according to the overwritten parameters, and obtains the measurement result of that candidate secondary cell. For details, please refer to the description of the common configuration and coverage field of candidate secondary cells, which will not be repeated here.

[0117] The terminal device sends a measurement report to the network device. The measurement report includes measurement results of at least one candidate primary cell and measurement results of candidate secondary cells associated with that candidate primary cell. This information can be carried in the MAC CE of the Layer 1 measurement report. Correspondingly, the network device receives the measurement results of the candidate primary cell and the candidate secondary cells associated with it. In the measurement report, the measurement results of the candidate secondary cells can be arranged in descending order of their activation priority. This ensures that the order of the candidate secondary cell measurement results in the measurement report is strictly aligned with the order of the candidate secondary cells in the associated configuration. This order alignment design allows the network device to associate the measurement results with the corresponding candidate secondary cells simply by their sequential position, without needing to carry the candidate secondary cell identifier for each measurement result when parsing the measurement report, thus significantly reducing the signaling overhead of the measurement report.

[0118] If there are multiple candidate primary cells, the measurement report can include the measurement results of all candidate primary cells, as well as the measurement results of candidate secondary cells associated with the multiple candidate primary cells. If at least two candidate primary cells are associated with the same candidate secondary cell, the measurement report can include only one measurement result for that candidate secondary cell to avoid duplicate reporting and reduce signaling overhead. The measurement report can be reported in the following ways: Method 1 and Method 2. Method 1, Figure 5 This is a schematic diagram of a MAC CE for a Layer 1 measurement report provided in an embodiment of this application. It should be noted that this embodiment does not limit the order of the information in the MAC CE. The measurement report includes a report identifier (ReportID), the measurement results of the candidate primary cell, and the measurement results of the candidate secondary cell associated with the candidate primary cell. The report identifier is used to indicate the type of measurement report. For example, when the report identifier is set to a pre-defined special value (e.g., 63), it indicates that the measurement report includes the measurement results of at least one candidate primary cell and the measurement results of the candidate secondary cell associated with the candidate primary cell, thus triggering the primary-secondary aggregation reporting mode.

[0119] In the payload section of MAC CE, the first beam block includes a first beam count (NumBeams) field and the measurement results of the candidate primary cell. The first beam count field indicates how many beams are included in the measurement results of the candidate primary cell. Subsequently, beam blocks (i.e., measurement results) of each candidate secondary cell are placed sequentially according to the order of entries in the associated configuration (i.e., from highest to lowest activation priority). This means the measurement results of candidate secondary cells can be arranged in the measurement report in descending order of activation priority. The beam block of a candidate secondary cell includes a second beam count field and the measurement results of that candidate secondary cell. The second beam count field indicates how many beams are included in the measurement results of the candidate secondary cell. The network device reaches the end of the beam block after reading the measurement results of the second beam count, and then immediately parses the beam block of the next candidate secondary cell.

[0120] The number of secondary cell measurement results is equal to the associated configuration length L. If the measurement result of a candidate secondary cell is invalid, the terminal device still needs to fill in the beam information block of the candidate secondary cell in the corresponding sequential position, and fill in invalid values ​​according to the invalid indication of the L1 measurement reporting format (for example, setting the second beam number field to 0) to ensure that the network device can correctly parse the measurement results of subsequent candidate secondary cells.

[0121] Method 2, Figure 6 This is a schematic diagram of another Layer 1 measurement report MAC CE provided in an embodiment of this application. The measurement report includes a report ID, measurement results of the candidate primary cell, measurement result validity information, and measurement results of the candidate secondary cell that is associated with and valid with the candidate primary cell. The measurement result validity information may be located before the measurement results of the candidate secondary cell that is associated with and valid with the candidate primary cell. When the report ID is set to a pre-defined special value (e.g., 63), the primary-secondary aggregation reporting mode is triggered. For information regarding the number of first beams, the number of second beams, and the measurement results of the candidate primary cell, refer to... Figure 5 The description will not be repeated here. Reserved bits indicate unused bits, which can be reserved for later expansion or set to a preset value (e.g., 0).

[0122] The measurement result validity information is used to indicate the candidate secondary cells with valid measurement results among all candidate secondary cells associated with the target primary cell. That is, the measurement report submitted this time includes the measurement results of the valid candidate secondary cells among all candidate secondary cells associated with the target primary cell.

[0123] For example, the validity information of measurement results can be represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the candidate primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell in the associated configuration, arranged in descending order of activation priority. If the i-th bit has a first value (e.g., 0), it indicates that the measurement result of the i-th candidate secondary cell is invalid and the current report does not include the measurement result of the i-th candidate secondary cell. If the i-th bit has a second value (e.g., 1), it indicates that the measurement result of the i-th candidate secondary cell is valid and the current report includes the measurement result of the i-th candidate secondary cell. i is a positive integer less than or equal to L. For example, assuming there are 8 secondary cells to be configured, the 8-bit bitmap 10101000 indicates that the measurement results of the 1st, 3rd, and 5th candidate secondary cells are valid, that is, the current report includes the measurement results of the 1st, 3rd, and 5th candidate secondary cells, and the measurement results of the remaining candidate secondary cells are invalid, that is, the current report does not include the measurement results of the remaining candidate secondary cells.

[0124] Measurement results of valid candidate secondary cells associated with the candidate primary cell refer to measurement results of candidate secondary cells whose validity information indicates they are valid. The measurement results of candidate secondary cells are arranged in the measurement report according to the bit order in the validity information (e.g., from high to low), which is also in descending order of activation priority. For example, if the validity information indicates that the measurement results of candidate secondary cells 1, 3, and 5 are valid, then the measurement results of valid candidate secondary cells will sequentially include the measurement results of candidate secondary cells 1, 3, and 5.

[0125] This bitmap indication method can provide a complete indication of the validity of measurement results for multiple candidate secondary cells with minimal signaling overhead. The terminal device uses this bitmap to determine which secondary cell measurement results should be included in the measurement report, and the network device uses the bitmap to determine the correspondence between each measurement result in the measurement report and the candidate secondary cells. This scheme achieves variable-length measurement reports while maintaining compatibility with fixed-order alignment mechanisms, balancing signaling efficiency and deterministic parsing.

[0126] Compared to Method 1, Method 2 has a variable MAC CE payload length. When there are many invalid candidate secondary cells in the associated configuration, it can reduce the total number of reported measurement results and lower signaling overhead. For example, compared to the method of reporting all associated secondary cell measurement results, this scheme can avoid reporting invalid measurement data when some secondary cells have poor signal quality or the measurement results are unavailable, thereby reducing the effective payload size of the measurement report and reducing the occupation of uplink signaling resources. At the same time, network devices only need to parse valid measurement results to make activation decisions, without having to process invalid data, thus improving the processing efficiency of network devices.

[0127] It should be noted that the terminal device can determine the validity of the measurement results of the candidate secondary cell using any of the following methods: In Method 1, the terminal device compares the measurement results of candidate secondary cells obtained from the measurements with a threshold pre-configured by the network device to determine whether the measurement results of the candidate secondary cells are valid. This threshold can be pre-configured by the network device via RRC signaling. When the measurement result of a candidate secondary cell is greater than or equal to the threshold, the terminal device determines that the measurement result of the candidate secondary cell is valid; otherwise, it determines that the measurement result of the candidate secondary cell is invalid. By judging the signal quality threshold, the terminal device can filter out secondary cells with sufficient signal strength to support data transmission, avoiding reporting measurement results of candidate secondary cells with weak signals that are unusable in practice.

[0128] Method 2: The terminal device determines the validity of the measurement results based on whether downlink synchronization with the candidate secondary cell has been successfully completed. The terminal device attempts to detect the SSB or Channel State Information Reference Signal (CSI-RS) transmitted by the candidate secondary cell and obtains the corresponding beam index. If the terminal device successfully detects the SSB or CSI-RS of the candidate secondary cell and can identify at least one usable beam direction, the measurement result of the candidate secondary cell is considered valid. If the terminal device cannot detect the SSB or CSI-RS of the candidate secondary cell, or the detected signal quality is so poor that it cannot be used for beam identification and subsequent channel estimation, the measurement result of the candidate secondary cell is considered invalid. Through synchronization status determination, the terminal device can ensure that the reported candidate secondary cells have usable downlink synchronization information, providing a physical layer basis for subsequent rapid activation.

[0129] Method 3: The terminal device determines the validity of the candidate secondary cell's measurement results based on the time difference between the measurement completion time and the reporting time. After completing the measurement of the candidate secondary cell, the terminal device records the completion time. When a measurement report needs to be generated, the terminal device calculates the time difference between the current time and the measurement completion time and compares this time difference with the effective duration pre-configured by the network device. The effective duration is pre-configured by the network device through radio resource control signaling, for example, configured as 100 milliseconds. If the time difference is less than or equal to the effective duration, the terminal device determines that the candidate secondary cell's measurement results are still valid and can be used for the network device's handover decision; otherwise, the measurement results are determined to be invalid, requiring re-measurement or abandonment of reporting. Through timeliness judgment, the terminal device avoids reporting outdated candidate secondary cell measurement results, preventing the network device from making incorrect activation decisions based on stale information.

[0130] Method 4: The terminal device determines the validity of the measurement results based on the availability of the measurement reference signal configured by the network device. The network device specifies the reference signal type and time-frequency resource location for each candidate secondary cell through configuration information. The reference signal includes at least one of the following: SSB, CSI-RS. The terminal device checks whether the time-frequency resource location of the reference signal configured by the network device is compatible with its current RF configuration and whether it can normally receive and demodulate the reference signal. If the time-frequency resource location of the reference signal is within the current operating frequency band of the terminal device, and the terminal device can successfully receive and demodulate the reference signal (e.g., correctly detect the reference signal sequence and calculate valid measurement values), the measurement result of the candidate secondary cell is determined to be valid. If the time-frequency resource location of the reference signal conflicts with the current operating frequency band of the terminal device, or the terminal device cannot demodulate the reference signal (e.g., sequence mismatch, signal energy too low), the measurement result of the candidate secondary cell is determined to be invalid. By determining the availability of the reference signal, the terminal device ensures that the reported measurement results are based on actually available reference signals, avoiding unreliable measurement results due to incorrect or incompatible reference signal configuration.

[0131] S103. The network device determines the target primary cell and the target secondary cell associated with the target primary cell based on the measurement results of at least one candidate primary cell and the measurement results of the candidate secondary cells associated with the candidate primary cell.

[0132] After receiving the measurement report reported by the terminal device, the network device identifies the report identifier as a special value (e.g., 63) and triggers the primary-secondary aggregation parsing mode. For Method 1 as described above, the network device can directly parse the measurement results of the candidate primary cell and the associated candidate secondary cell. For Method 2 as described above, the network device can determine which candidate secondary cell measurement results are included in this report based on the measurement result validity information. It sequentially parses the measurement results of the candidate primary cell and the valid candidate secondary cell, matching each valid candidate secondary cell's measurement result with the candidate secondary cells in the associated configuration based on the measurement result validity information. Then, based on the measurement results of at least one candidate primary cell and the measurement results of the candidate secondary cells associated with the candidate primary cell, and optionally, based on network resource policies (e.g., load balancing, spectrum efficiency, etc.) and operator policies, the network device determines the target primary cell (e.g., target primary cell identifier) ​​and the target secondary cell associated with the target primary cell. For example, the candidate primary cell with the best signal quality is selected as the target primary cell, and the candidate secondary cell with the best signal quality among all candidate secondary cells associated with the target primary cell is selected as the target secondary cell associated with the target primary cell.

[0133] S104. The network device sends a handover command to the terminal device.

[0134] Accordingly, the terminal device receives a handover command from the network device. Figure 7 This is a schematic diagram of a MAC CE for a handover command provided in an embodiment of this application. The network device extends the existing LTM cell handover command MAC CE field by adding new fields to carry new information. The existing LTM cell handover command MAC CE includes the target primary cell identifier. The new information in the handover command includes at least one of the following: secondary cell activation information and synchronization validity information.

[0135] Secondary cell activation information is used to indicate the activated target secondary cells associated with the target primary cell. For example, secondary cell activation information can be represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the target primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell in the target primary cell's associated configuration, arranged in descending order of activation priority. A first value (e.g., 0) for the i-th bit indicates that the corresponding candidate secondary cell is not activated; a second value (e.g., 1) for the i-th bit indicates that the corresponding candidate secondary cell is activated. i is a positive integer less than or equal to L. Assuming there are 8 secondary cells to configure, the 8-bit bitmap 10101000 indicates that the 1st, 3rd, and 5th candidate secondary cells are activated, meaning the target secondary cells associated with the target primary cell are the 1st, 3rd, and 5th candidate secondary cells, and the remaining candidate secondary cells are not activated. If the handover command does not include secondary cell activation information, it means that all candidate secondary cells associated with the target primary cell in the measurement report are activated; that is, the target secondary cells associated with the target primary cell are all candidate secondary cells associated with the target primary cell.

[0136] This bitmap indication method can indicate the activation status of multiple candidate secondary cells with minimal signaling overhead. Compared with listing candidate secondary cell identifiers one by one, it significantly reduces the payload of handover commands. At the same time, the implicit correspondence between the bitmap and the associated configuration order allows the terminal device to quickly determine the candidate secondary cells to be activated without parsing additional identifier information, thus reducing the processing latency of handover commands.

[0137] In a co-located CA scenario, the target primary cell and its associated candidate secondary cell are located at the same base station, sharing the same TA value and synchronization information (e.g., SSB beam direction). In this case, the network device can determine whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell.

[0138] In non-co-located CA scenarios, the target primary cell and associated candidate secondary cells may be located in different geographical locations. For example, the primary cell may be in a macro cell, while the secondary cell may be in a remote micro cell or radio frequency remote unit. In this case, the network device can further determine whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell based on at least one of the following: The relative positions between cells are determined by the fact that if the distance between the target primary cell and the associated candidate secondary cell is less than a threshold, then the synchronization information of the target primary cell is considered valid in the associated candidate secondary cell.

[0139] If the signal quality change trends of the target primary cell and the associated candidate secondary cell are consistent (e.g., rising or falling together), it indicates that the spatial correlation between the target primary cell and the associated candidate secondary cell is high, and the synchronization information of the target primary cell is deemed to be valid in the associated candidate secondary cell.

[0140] The time difference between the time the measurement report is received and the time the handover command is issued: If the time difference is less than the threshold (e.g., 100ms), it is determined that the synchronization information of the target primary cell is valid in the associated candidate secondary cell.

[0141] If none of the above conditions are met, the synchronization information of the target primary cell is deemed invalid in the associated candidate secondary cell.

[0142] Synchronization validity information indicates whether the synchronization information (such as TA value and SSB) of the target primary cell is valid in the associated candidate secondary cells. If the handover command does not include synchronization validity information, the terminal device assumes that the synchronization information of the target primary cell is valid in all associated candidate secondary cells.

[0143] For example, synchronization validity information can be represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the target primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell in the target primary cell's associated configuration, arranged in descending order of activation priority. If the i-th bit has a first value (e.g., 0), it indicates that the synchronization information of the target primary cell is invalid in the associated i-th candidate secondary cell, meaning that the synchronization information of the target primary cell may be outdated. The terminal device needs to verify the validity of the synchronization information of the target primary cell in the i-th candidate secondary cell before using it, or it can backtrack to search for the SSB of the i-th candidate secondary cell to complete the synchronization with the i-th candidate secondary cell. If the i-th bit has a second value (e.g., 1), it indicates that the synchronization information of the target primary cell is valid in the associated i-th candidate secondary cell, and the terminal device can directly reuse the TA and pre-configured SSB of the target primary cell in the i-th candidate secondary cell. i is a positive integer less than or equal to L. Assuming there are 8 secondary cells to be configured, the 8-bit diagram 10101000 indicates that the synchronization information of the target primary cell is valid in the 1st, 3rd, and 5th associated candidate secondary cells, and invalid in the remaining candidate secondary cells.

[0144] If the handover command includes secondary cell activation information and synchronization validity information, it means the following: The i-th bit of the secondary cell activation information bitmap is 1, and the i-th bit of the synchronization validity information bitmap is 1: the i-th candidate secondary cell in the activation target primary cell associated configuration is arranged in descending order of activation priority. Furthermore, the synchronization information of the target primary cell is valid in the associated i-th candidate secondary cell, and the terminal device directly reuses the synchronization information of the target primary cell (e.g., TA and SSB) in the i-th candidate secondary cell.

[0145] The i-th bit of the secondary cell activation information bitmap is 1, and the i-th bit of the synchronization validity information bitmap is 0: the i-th candidate secondary cell in the target primary cell association configuration is arranged in descending order of activation priority. However, the synchronization information of the target primary cell may be outdated in the associated i-th candidate secondary cell. The terminal device needs to verify the synchronization information of the target primary cell in the i-th candidate secondary cell before using the synchronization information of the target primary cell, or backtrack to search for the SSB of the i-th candidate secondary cell to complete the synchronization with the i-th candidate secondary cell.

[0146] The i-th bit of the secondary cell activation information bitmap is 0, and the i-th bit of the synchronization validity information bitmap is 1: This is an invalid combination, and the terminal device ignores the configuration of the i-th candidate secondary cell.

[0147] This synchronization validity indication mechanism enables terminal devices to distinguish the synchronization information status of different secondary cells when activating them: for secondary cells with a valid validity indication, the terminal device can directly reuse the synchronization information of the primary cell (e.g., TA value and SSB), achieving activation with zero additional latency. For secondary cells with an invalid validity indication, the terminal device verifies the validity of the target primary cell's synchronization information and then uses that information; alternatively, it may backtrack and search for the SSB of candidate secondary cells to avoid activation failure due to the use of outdated synchronization information. This mechanism maximizes rapid activation while ensuring a high activation success rate, balancing efficiency and reliability.

[0148] S105. The terminal device switches to the target primary cell according to the handover command and activates the target secondary cell associated with the target primary cell.

[0149] Specifically, Figure 8 This is a flowchart illustrating another switching method provided in an embodiment of this application. S105 includes S1051-S1054: S1051. The terminal device switches to the target primary cell indicated by the target primary cell identifier in the handover command.

[0150] This allows for handover without undergoing the full RRC reconfiguration process. The terminal device synchronizes with the target primary cell in the following ways: If a TA (Temporary Access Registry) has been obtained through a pre-synchronization mechanism, the terminal device directly uses that TA to synchronize with the target primary cell. If the TA is unknown, the terminal device can perform a random access procedure in the target primary cell to complete synchronization. Since the secondary cell and primary cell belong to the same timing advance group (TAG) in a co-located CA scenario, no additional random access procedure is required for the secondary cell.

[0151] S1052. The terminal device determines the target secondary cell associated with the target primary cell to be activated based on the secondary cell activation information in the handover command.

[0152] The terminal device iterates through the secondary cell activation information bitmap from low to high bit, taking the values ​​of each bit. If the i-th bit of the secondary cell activation information bitmap is the second value, then the i-th candidate secondary cell in the associated configuration of the target primary cell is determined as the target secondary cell. That is, secondary cells are activated in descending order of activation priority, so that the candidate secondary cell with the highest activation priority (ranked before the associated configuration) is activated first. i is a positive integer less than or equal to L.

[0153] The terminal device restores the activation context of the secondary cell. Specifically, this includes: S1053. If the overlay field in the associated configuration is configured with the third TCI state for the candidate secondary cell, the terminal device shall give priority to using the third TCI state, rather than the second TCI state (default TCI state) in the common configuration.

[0154] S1054. The terminal device performs synchronization with the candidate secondary cell based on the synchronization validity information in the handover command.

[0155] Specifically, step S1054 includes S10541 and S10542.

[0156] S10541. If the synchronization validity information in the handover command indicates that the synchronization information of the target primary cell is invalid in the associated i-th candidate secondary cell, the terminal device needs to verify the synchronization information of the target primary cell in the i-th candidate secondary cell before using the synchronization information of the target primary cell, or, backtrack to search for the SSB of the i-th candidate secondary cell to complete the synchronization with the i-th candidate secondary cell.

[0157] S10542. If the handover command does not include synchronization validity information, or if the synchronization validity information in the handover command indicates that the synchronization information of the target primary cell is valid in the associated i-th candidate secondary cell, the terminal device can directly use the synchronization information of the target primary cell in the i-th candidate secondary cell to complete the synchronization with the i-th candidate secondary cell.

[0158] In addition, candidate secondary cells that are not in the current target primary cell association configuration are not within the activation scope of this handover, and their status is controlled by subsequent signaling from the network equipment.

[0159] During subsequent maintenance phases, such as when the terminal device is camped on the target primary cell, the network device can update the configuration information through RRC reconfiguration messages.

[0160] For example, a network device can send a first update command to a terminal device via an RRC reconfiguration message, and the terminal device receives the first update command from the network device. The first update command is used to update the parameters of the common configuration of candidate secondary cells in the candidate secondary cell configuration. The first update command includes a common configuration identifier and the updated parameters of the common configuration. After receiving the first update command, the terminal device overwrites the parameters of the common configuration corresponding to the common configuration identifier with the updated parameters of the common configuration in the first update command.

[0161] For example, a network device can send a deletion command to a terminal device via an RRC reconfiguration message. The terminal device then receives the deletion command from the network device. The deletion command is used to delete the common configuration of a candidate secondary cell in the candidate secondary cell configuration. The deletion command includes a common configuration identifier. After receiving the deletion command, the terminal device deletes the common configuration of the candidate secondary cell corresponding to the common configuration identifier in the candidate secondary cell configuration. If the common configuration identifier is still referenced by an associated configuration, the deletion command can also include the updated associated configuration. Alternatively, the terminal device can directly delete the entry in the associated configuration that involves the common configuration identifier. This avoids the inconsistency of "the common configuration has been deleted but the associated configuration is still referenced."

[0162] For example, a network device can send an add command to a terminal device via an RRC reconfiguration message, and the terminal device receives the add command from the network device. The add command is used to add the common configuration of a candidate secondary cell to the candidate secondary cell configuration. The add command includes a common configuration identifier and the corresponding common configuration of the candidate secondary cell. After receiving the add command, the terminal device adds the common configuration of the candidate secondary cell and the corresponding common configuration identifier from the add command to the candidate secondary cell configuration.

[0163] For example, a network device can send a second update command to a terminal device via an RRC reconfiguration message. The terminal device then receives the second update command from the network device. This second update command updates the associated configuration. It includes the updated associated configuration. Upon receiving the second update command, the terminal device overwrites the original associated configuration with the updated configuration from the second update command.

[0164] The handover method provided in this application involves a terminal device performing measurements on at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell based on received configuration information. The measurement results of at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell are reported together in the measurement report. This allows the network device to comprehensively evaluate the signal quality of the primary and secondary cells, thereby determining the target primary cell that the terminal device needs to hand over to, and the target secondary cell associated with the target primary cell that needs to be activated. A handover command is then sent to the terminal device. The handover command includes not only the target primary cell identifier but may also include at least one of secondary cell activation information and synchronization validity information. The secondary cell activation information indicates the activated target secondary cell associated with the target primary cell, and the synchronization validity information indicates whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell. On the one hand, by merging the activation of the secondary cell and the handover of the primary cell under the same handover command, the serial delay of handover followed by activation in traditional schemes is avoided, achieving simultaneous handover of primary and secondary cells. On the other hand, through the synchronization validity information, the terminal device can directly reuse the primary cell's TA value to achieve zero-additional-delay activation when the synchronization information is valid. This reduces the activation latency of secondary cells during LTM handover while ensuring activation success rate, thus balancing activation efficiency and reliability.

[0165] Figure 9 This is a schematic diagram of a communication device provided in an embodiment of this application. The communication device 900 may include a communication module 910. The communication module 910 can implement corresponding communication functions, which can be internal communication functions of the communication device 900 or communication functions between the communication device 900 and other devices. Optionally, the communication module 910 may also be referred to as a communication interface or a transceiver module. Optionally, the communication device 900 may further include a processing module 920. The processing module 920 can implement corresponding processing functions.

[0166] Optionally, the communication device 900 may further include a storage module 930, which can be used to store instructions and / or data; the processing module 920 can read the instructions and / or data in the storage module 930 so that the communication device 900 can implement the aforementioned method embodiments.

[0167] In one possible design, the communication device 900 may correspond to the terminal device in the above method embodiments, or a component (e.g., circuit, chip, or chip system) configured in the terminal device. The communication device 900 can be used to perform the steps or processes performed by the terminal device in any of the above method embodiments.

[0168] For example, the communication module 910 is used to receive configuration information; the configuration information is used to configure the terminal device to perform synchronization, measurement, and transmission on at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell; perform measurements on at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell according to the configuration information, and send a measurement report, the measurement report including the measurement results of at least one candidate primary cell and the measurement results of the candidate secondary cells associated with the candidate primary cell; receive a handover command; the handover command includes a target primary cell identifier and at least one of the following: secondary cell activation information and synchronization validity information; the secondary cell activation information is used to indicate the activated target secondary cell associated with the target primary cell, and the synchronization validity information is used to indicate whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell. The processing module 920 is used to hand over to the target primary cell and activate the candidate secondary cell according to the handover command.

[0169] In one possible design, the communication device 900 may correspond to the network device in the above method embodiments, or to a component (e.g., circuitry, chip, or chip system) configured within the network device. The communication device 900 can be used to execute the steps or processes performed by the network device in any of the above method embodiments.

[0170] For example, the communication module 910 is used to send configuration information; the configuration information is used to configure the terminal device to perform synchronization, measurement and transmission on at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell; receive a measurement report, the measurement report including the measurement results of at least one candidate primary cell and the measurement results of candidate secondary cells associated with the candidate primary cell; send a handover command; the handover command includes a target primary cell identifier and at least one of the following: secondary cell activation information and synchronization validity information; the secondary cell activation information is used to indicate the activated target secondary cell associated with the target primary cell, and the synchronization validity information is used to indicate whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell; the handover command is used to trigger the terminal device to hand over to the target primary cell and activate the candidate secondary cell.

[0171] Figure 10 This is a schematic diagram of another communication device provided in an embodiment of this application. The communication device 1000 may be a chip, chip system, or processor, etc., used in a terminal device or network device to implement the above-described methods. The communication device 1000 can be used to implement the methods described in the above-described method embodiments; for details, please refer to the descriptions in the above-described method embodiments.

[0172] like Figure 10As shown, the communication device 1000 may include one or more processors 1010, which may also be referred to as processing units or processing modules, and can implement certain control functions. The processor 1010 may be a general-purpose processor or a dedicated processor, such as a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, while the central processing unit can be used to control the communication device 1000 (e.g., a base station, baseband chip, user, user chip), execute software programs, and process data from the software programs.

[0173] In an alternative design, the processor 1010 may also store instructions and / or data, which can be executed by the processor 1010 to cause the communication device 1000 to perform the methods described in the above method embodiments.

[0174] In another alternative design, the communication device 1000 may include a communication interface 1020 for implementing receiving and transmitting functions. For example, the communication interface 1020 may be a transceiver circuit, interface, interface circuit, or transceiver. The transceiver circuit, interface, interface circuit, or transceiver for implementing receiving and transmitting functions may be separate or integrated. The aforementioned transceiver circuit, interface, interface circuit, or transceiver may be used for reading and writing code / data, or it may be used for transmitting or relaying signals.

[0175] Optionally, the communication device 1000 may include one or more memories 1030, which may store instructions that can be executed on the processor 1010, causing the communication device 1000 to perform the methods described in the above method embodiments. Optionally, the memories 1030 may also store data. Optionally, the processor 1010 may also store instructions and / or data. The processor 1010 and the memories 1030 may be provided separately or integrated together.

[0176] It should be understood that, in one possible design, the steps in the method embodiments provided in this application can be implemented by integrated logic circuits in the processor's hardware or by instructions in software form. The steps of the methods disclosed in the embodiments of this application can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules in the processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are not provided here.

[0177] In one implementation, the communication device 1000 may correspond to the terminal device in the above method embodiments and may be used to execute the various steps and / or processes executed by the terminal device in the above method embodiments. The processor 1010 may be used to execute instructions stored in the memory 1030, and when the processor 1010 executes the instructions stored in the memory, the processor 1010 is used to execute the various steps and / or processes of the above method embodiments corresponding to the terminal device.

[0178] In another implementation, the communication device 1000 may correspond to the network device in the above method embodiments and may be used to execute the various steps and / or processes executed by the network device in the above method embodiments. The processor 1010 may be used to execute instructions stored in the memory 1030, and when the processor 1010 executes the instructions stored in the memory, the processor 1010 is used to execute the various steps or processes of the above method embodiments corresponding to the network device.

[0179] In another implementation, the communication device 1000 may correspond to the network device in the above method embodiments and may be used to execute the various steps or processes executed by the network device in the above method embodiments. The processor 1010 may be used to execute instructions stored in the memory 1030, and when the processor 1010 executes the instructions stored in the memory, the processor 1010 is used to execute the various steps or processes of the above method embodiments corresponding to the network device.

[0180] It should be understood that the aforementioned processor can be one or more chips. For example, the processor can be a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a system-on-chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD), or other integrated chips.

[0181] 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.

[0182] According to the method provided in the embodiments of this application, this application also provides a processor, including: an input circuit, an output circuit, and a processing circuit. The processing circuit is used to receive signals through the input circuit and transmit signals through the output circuit, causing the processor to execute the method described in the embodiments of this application.

[0183] In specific implementation, the processor can be one or more chips, the input circuit can be input pins, the output circuit can be output pins, and the processing circuit can be transistors, gate circuits, flip-flops, and various logic circuits. The input signal received by the input circuit can be received and input by, for example, but not limited to, a receiver, and the signal output by the output circuit can be, for example, but not limited to, output to and transmitted by a transmitter. Furthermore, the input circuit and the output circuit can be the same circuit, which is used as both the input circuit and the output circuit at different times. This application does not limit the specific implementation of the processor and various circuits.

[0184] According to the method provided in the embodiments of this application, this application also provides a chip system, which includes one or more processors for calling and executing instructions stored in memory, thereby causing the method described in the embodiments of this application to be executed. The chip system may be composed of chips or may include chips and other discrete devices.

[0185] The chip system may include input circuits or interfaces for transmitting information or data, and output circuits or interfaces for receiving information or data.

[0186] According to the method provided in the embodiments of this application, this application also provides a communication system, which includes the aforementioned terminal device and network device.

[0187] According to the method provided in the embodiments of this application, this application also provides a computer program product, which includes: computer program code, which, when run on a computer, causes the computer to execute the various steps or processes executed by the terminal device or network device in any of the foregoing method embodiments.

[0188] According to the method provided in the embodiments of this application, this application also provides a computer-readable storage medium storing program code, which, when run on a computer, causes the computer to execute the various steps or processes executed by the terminal device or network device in any of the foregoing method embodiments.

[0189] The computer-readable storage medium may be the aforementioned volatile memory or non-volatile memory, or it may include both volatile memory and non-volatile memory.

[0190] In the embodiments of this application, the terms and English abbreviations are exemplary examples given for ease of description and should not be construed as limiting the application in any way. This application does not preclude the possibility of defining other terms that can achieve the same or similar functions in existing or future agreements.

[0191] 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.

[0192] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0193] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0194] In summary, the above description is merely a preferred embodiment of the technical solution of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A handover method, characterized by, Applied to a terminal device, the method includes: Receive configuration information; the configuration information is used to configure the terminal device to perform synchronization, measurement and transmission on at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell; Measurements are performed on at least one candidate primary cell and a candidate secondary cell associated with the candidate primary cell according to the configuration information, and a measurement report is sent. The measurement report includes the measurement results of at least one candidate primary cell and the measurement results of the candidate secondary cell associated with the candidate primary cell. Receive a handover command; the handover command includes a target primary cell identifier and at least one of the following: secondary cell activation information and synchronization validity information; the secondary cell activation information is used to indicate the activated target secondary cell associated with the target primary cell, and the synchronization validity information is used to indicate whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell; The handover command is used to switch to the target primary cell and activate the candidate secondary cell. If the handover command does not include the synchronization validity information, or if the synchronization validity information indicates that the synchronization information of the target primary cell is valid in the associated candidate secondary cell, then the synchronization information of the target primary cell is used in the associated candidate secondary cell. If the synchronization validity information indicates that the synchronization information of the target primary cell is invalid in the associated candidate secondary cell, then in the associated candidate secondary cell, the synchronization information of the target primary cell is verified as valid and then used; or, a fallback search is performed for the synchronization signal block (SSB) of the associated candidate secondary cell to complete synchronization with the associated candidate secondary cell.

2. The method of claim 1, wherein, The configuration information includes at least one of the following: candidate primary cell configuration, candidate secondary cell configuration, and association configuration; The candidate primary cell configuration is used to configure the terminal device to perform synchronization, measurement, and transmission on at least one candidate primary cell, and the candidate secondary cell configuration is used to configure the terminal device to perform synchronization, measurement, and transmission on candidate secondary cells; the candidate secondary cell configuration includes the common configuration of candidate secondary cells; the associated configuration is used to indicate the common configuration of candidate secondary cells associated with the candidate primary cell in the candidate secondary cell configuration.

3. The method according to claim 2, characterized in that, The candidate secondary cell configuration also includes a common configuration identifier corresponding to the common configuration of the candidate secondary cells; each entry in the associated configuration includes at least one of the following: The common configuration identifier is used to indicate the common configuration of the candidate secondary cell associated with the candidate primary cell in the candidate secondary cell configuration; The override field is used to override the default value in the common configuration of the candidate secondary cells associated with the candidate primary cell.

4. The method according to claim 3, characterized in that, The coverage field includes at least one of the following: a third synchronization signal block (SSB) configuration for covering the second SSB configuration in the common configuration of the candidate secondary cell; a third transmission configuration indicating TCI status for covering the second TCI status in the common configuration of the candidate secondary cell; a third reference signal configuration for covering the second reference signal configuration in the common configuration of the candidate secondary cell; the SSB configuration indicates the parameters of the SSB used by the terminal device to perform synchronization, the TCI status indicates the beam used by the terminal device to receive signals, and the reference signal configuration indicates the parameters of the reference signal used by the terminal device to measure the cell signal quality.

5. The method according to claim 3, characterized in that, All entries in the associated configuration are arranged in descending order of the activation priority of the secondary cell.

6. The method according to any one of claims 1-5, characterized in that, The secondary cell activation information is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the target primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. The i-th bit is the first value, indicating that the corresponding candidate secondary cell is not activated; the i-th bit is the second value, indicating that the corresponding candidate secondary cell is activated.

7. The method according to any one of claims 1-5, characterized in that, The synchronization validity information is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the target primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. If the i-th bit is a first value, it indicates that the synchronization information of the target primary cell is invalid in the associated i-th candidate secondary cell; if the i-th bit is a second value, it indicates that the synchronization information of the target primary cell is valid in the associated i-th candidate secondary cell.

8. The method according to any one of claims 1-5, characterized in that, The measurement results of the candidate secondary cells are arranged in descending order of their activation priority.

9. The method according to any one of claims 1-5, characterized in that, The measurement report also includes measurement result validity information, which is used to indicate the candidate secondary cells with valid measurement results among all candidate secondary cells associated with the candidate primary cell; the measurement results of the candidate secondary cells associated with the candidate primary cell in the measurement report refer to the measurement results of the candidate secondary cells that are valid as indicated by the measurement result validity information.

10. The method according to claim 9, characterized in that, The validity information of the measurement results is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the candidate primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. If the i-th bit is a first value, it indicates that the measurement result of the i-th candidate secondary cell is invalid; if the i-th bit is a second value, it indicates that the measurement result of the i-th candidate secondary cell is valid.

11. A switching method, characterized in that, Applied to network devices, the method includes: Send configuration information; the configuration information is used to configure the terminal device to perform synchronization, measurement and transmission on at least one candidate primary cell and candidate secondary cells associated with the candidate primary cell; Receive a measurement report, the measurement report including measurement results of at least one candidate primary cell and measurement results of candidate secondary cells associated with the candidate primary cell; Send a handover command; the handover command includes a target primary cell identifier and at least one of the following: secondary cell activation information and synchronization validity information; the secondary cell activation information is used to indicate the activated target secondary cell associated with the target primary cell, and the synchronization validity information is used to indicate whether the synchronization information of the target primary cell is valid in the associated candidate secondary cell; the handover command is used to trigger the terminal device to hand over to the target primary cell and activate the candidate secondary cell.

12. The method according to claim 11, characterized in that, The configuration information includes at least one of the following: candidate primary cell configuration, candidate secondary cell configuration, and association configuration; The candidate primary cell configuration is used to configure the terminal device to perform synchronization, measurement, and transmission on at least one candidate primary cell, and the candidate secondary cell configuration is used to configure the terminal device to perform synchronization, measurement, and transmission on candidate secondary cells; the candidate secondary cell configuration includes the common configuration of candidate secondary cells; the associated configuration is used to indicate the common configuration of candidate secondary cells associated with the candidate primary cell in the candidate secondary cell configuration.

13. The method according to claim 12, characterized in that, The candidate secondary cell configuration also includes a common configuration identifier corresponding to the common configuration of the candidate secondary cells; each entry in the associated configuration includes at least one of the following: The common configuration identifier is used to indicate the common configuration of the candidate secondary cell associated with the candidate primary cell in the candidate secondary cell configuration; The override field is used to override the default value in the common configuration of the candidate secondary cells associated with the candidate primary cell.

14. The method according to claim 13, characterized in that, The coverage field includes at least one of the following: a third synchronization signal block (SSB) configuration for covering the second SSB configuration in the common configuration of the candidate secondary cell; a third transmission configuration indicating TCI status for covering the second TCI status in the common configuration of the candidate secondary cell; a third reference signal configuration for covering the second reference signal configuration in the common configuration of the candidate secondary cell; the SSB configuration indicates the parameters of the SSB used by the terminal device to perform synchronization, the TCI status indicates the beam used by the terminal device to receive signals, and the reference signal configuration indicates the parameters of the reference signal used by the terminal device to measure the cell signal quality.

15. The method according to claim 13, characterized in that, All entries in the associated configuration are arranged in descending order of the activation priority of the secondary cell.

16. The method according to any one of claims 11-15, characterized in that, The secondary cell activation information is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the target primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. The i-th bit is the first value, indicating that the corresponding candidate secondary cell is not activated; the i-th bit is the second value, indicating that the corresponding candidate secondary cell is activated.

17. The method according to any one of claims 11-15, characterized in that, The synchronization validity information is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the target primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. If the i-th bit is a first value, it indicates that the synchronization information of the target primary cell is invalid in the associated i-th candidate secondary cell; if the i-th bit is a second value, it indicates that the synchronization information of the target primary cell is valid in the associated i-th candidate secondary cell.

18. The method according to any one of claims 11-15, characterized in that, The measurement results of the candidate secondary cells are arranged in descending order of their activation priority.

19. The method according to any one of claims 11-15, characterized in that, The measurement report also includes measurement result validity information, which is used to indicate the candidate secondary cells with valid measurement results among all candidate secondary cells associated with the candidate primary cell; the measurement results of the candidate secondary cells associated with the candidate primary cell in the measurement report refer to the measurement results of the candidate secondary cells that are valid as indicated by the measurement result validity information.

20. The method according to claim 19, characterized in that, The validity information of the measurement results is represented by a bitmap. The length of the bitmap is greater than or equal to the number L of candidate secondary cells associated with the candidate primary cell. The i-th bit of the bitmap corresponds to the i-th candidate secondary cell arranged in descending order of activation priority. If the i-th bit is a first value, it indicates that the measurement result of the i-th candidate secondary cell is invalid; if the i-th bit is a second value, it indicates that the measurement result of the i-th candidate secondary cell is valid.

21. A communication device, characterized in that, The device includes a processor and a memory, wherein the memory stores instructions, and when the processor executes the instructions, the communication device performs the method as described in any one of claims 1-20.

22. A communication system, characterized in that, The method includes a terminal device and a network device, wherein the terminal device is used to perform the method as described in any one of claims 1-10, and the network device is used to perform the method as described in any one of claims 11-20.

23. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed, they cause the computer to perform the method as described in any one of claims 1-20.

24. A computer program product containing instructions, characterized in that, When the instructions are executed on a computer, the computer causes the computer to perform the method as described in any one of claims 1-20.

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