Communication method and device

Abstract

The embodiment of the present application discloses a communication method and apparatus to solve the problem of service interruption caused by RLF in the first main cell when the terminal device adds a PSCell. The method includes: before determining the cell that meets the conditions for adding the main and auxiliary cells according to the CPA information, or before successfully accessing the cell that meets the conditions for adding the main and auxiliary cells after determining the cell that meets the conditions for adding the main and auxiliary cells, if RLF is detected in the first main cell, then determine the target cell, add the target cell as the target main and auxiliary cell, or perform an RRC re-establishment process on the target cell, or delete / release the first main cell, and use the target cell as the second main cell. The target cell can be a cell that meets the conditions for adding the main and auxiliary cells or a cell selected by the terminal device according to the S criterion or other selection conditions. The scheme of the present application can be widely applied to the fields of communication technology, artificial intelligence, Internet of Vehicles, smart home networking, etc.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of communication technology, and in particular, to a communication method and device. Background Art

[0002] At present, in order to improve the reliability of adding secondary nodes (SN) / primary secondary cells (PSCell), a conditional PSCell addition (CPA) process is proposed. For example, the master node (MN) sends CPA information of multiple candidate PSCells to the terminal device through one or more radio resource control (RRC) messages. Among them, for each candidate PSCell, the CPA information may include PSCell addition condition (also referred to as SN addition condition) information and configuration information. Among them, the PSCell addition condition information may include a PSCell addition execution event and a threshold value corresponding to the event. Then, the terminal device uses the candidate PSCell that meets the above-mentioned addition condition information as the PSCell to be accessed (or the target PSCell), accesses the PSCell, and improves the success rate of adding the PSCell or adding the SN.

[0003] However, in the process of the terminal device determining whether the candidate PSCell meets the PSCell addition conditions, if the terminal device detects that a radio link failure (RLF) occurs in the primary cell (PCell) or master cell group (MCG) on the MN, the terminal device will execute the radio resource control (RRC) reestablishment (RRC reestablishment) process, thereby causing service interruption between the terminal device and the network device. Summary of the invention

[0004] The embodiments of the present application provide a communication method and system to solve the problem of service interruption caused by RLF in the primary cell when the terminal device executes the PSCell adding process.

[0005] In order to achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides a communication method, which can be executed by a terminal device, a chip or other apparatus. Taking the method being executed by a terminal device as an example, the method may include: the terminal device receives conditional primary and secondary cell addition (conditional PSCell addition, CPA) information configured by a first main network device, the CPA information indicating parameters of at least one candidate primary and secondary cell and primary and secondary cell addition condition information of each candidate primary and secondary cell, and before determining a cell that meets the primary and secondary cell addition condition according to the CPA information, the terminal device detects that a radio link failure (radio link failure, RLF) occurs in a first main cell managed by the first main network device, determines a target cell from at least one candidate primary and secondary cell, adds the target cell as a target primary and secondary cell, or performs an RRC re-establishment process on the target cell, or deletes the first main cell and uses the target cell as a second main cell.

[0007] Based on the method described in the first aspect, before the terminal device determines the target primary and secondary cells to be added, if the first primary cell has an RLF, the terminal device selects a cell to be reestablished from the candidate primary and secondary cells, and initiates an RRC reestablishment process to the selected cell. Since the context information of the terminal device has been exchanged between the source PCell and the candidate PSCell, and the service data of the terminal device has been forwarded, the terminal device can quickly reestablish with the selected cell, reduce the service interruption time between the terminal device and the network device, and ensure the service transmission between the terminal device and the network device. Alternatively, before the terminal device determines the target PSCell to be added, if the first primary cell has an RLF, the terminal device selects a cell that meets a certain condition from the candidate PSCell as a new primary cell, and accesses the primary cell. Since the PSCell signal quality selected from the candidate PSCell that can be used as the new primary cell is better, and in the candidate SN addition preparation stage, the candidate PSCell has obtained the terminal device context, the terminal device can quickly access the new primary cell, reduce the service interruption time between the terminal device and the network device, and ensure the service transmission between the terminal device and the network device. Alternatively, before the terminal device determines the target PSCell to be added, if RLF occurs in the first main cell, the terminal device selects a target PSCell that meets the PSCell adding conditions from the candidate PSCells as the primary and secondary cells to be added. Since the signal quality of the cells that meet the PSCell adding conditions in the candidate PSCells is better, and the candidate PSCell has obtained the terminal device context in the candidate SN adding preparation stage, the terminal device can quickly access the cell that meets the PSCell adding conditions, and the cell provides business services for the terminal device, thereby reducing the business interruption time between the terminal device and the network device and ensuring the business transmission between the terminal device and the network device.

[0008] In one possible design, the terminal device determines the target cell, including: the terminal device takes a cell that meets the S criterion among at least one candidate primary and secondary cell as the target cell.

[0009] Based on this possible design, the terminal device can select the target cell from the candidate primary and secondary cells according to the S criterion. Since the S criterion is a cell selection criterion, or a criterion for selecting a cell for RRC re-establishment, the target cell selected by the terminal device has better quality. Since the selected target cell belongs to the candidate primary and secondary cells, and the candidate primary and secondary cells have the context information of the terminal device, the terminal device can quickly re-establish with the selected target cell, thereby reducing the service interruption time between the terminal device and the network device and ensuring the service transmission between the terminal device and the network device.

[0010] In one possible design, the terminal device determines the target cell, including: the terminal device determines whether there is a cell that meets the first selection condition in at least one candidate primary and secondary cell; if there is a cell that meets the first selection condition in at least one candidate primary and secondary cell, the terminal device will take the cell that meets the first selection condition as the target cell, and the first selection condition is to add a condition to the primary and secondary cell or to have a signal quality greater than a first threshold.

[0011] Based on this possible design, the terminal device can take the cell in the candidate PSCell that meets the conditions for adding the primary and secondary cells or whose signal quality is greater than the first threshold as the target cell, that is, select the PSCell with better signal quality from the candidate PSCell as the target cell, so that the terminal device can quickly access the target cell with better signal quality, and the cell provides the terminal device with relatively high-quality business services, ensuring the continuity of business transmission and unaffected transmission quality.

[0012] In one possible design, if there is no cell satisfying the first selection condition in at least one candidate primary and secondary cell, the terminal device determines the target cell, including: taking a cell satisfying the S criterion in at least one candidate primary and secondary cell as the target cell.

[0013] Based on this possible design, when there is no cell meeting the first selection condition in the candidate PSCell, the terminal device can select the target cell from the candidate primary and secondary cells according to the S criterion, that is, the terminal device can select the target cell according to the S criterion for selecting the RRC re-establishment cell. Since the S criterion is a cell selection criterion, or a criterion for selecting the RRC re-establishment cell, the target cell selected by the terminal device has better quality. Since the selected target cell belongs to the candidate primary and secondary cells, and the candidate primary and secondary cells have the context information of the terminal device, the terminal device can quickly reestablish with the selected target cell, thereby reducing the service interruption time between the terminal device and the network device and ensuring the service transmission between the terminal device and the network device.

[0014] In one possible design, the terminal device determines the target cell, including: within the validity period of the timer, judging whether there is a cell that meets the conditions for adding the primary and secondary cells in at least one candidate primary and secondary cell; if there is a cell that meets the conditions for adding the primary and secondary cells in at least one candidate primary and secondary cell, the cell that meets the conditions for adding the primary and secondary cells is used as the target cell.

[0015] Based on this possible design, the terminal device can select a cell that meets the PSCell addition conditions from the candidate PSCells as the target cell within the validity period / a certain time, thereby ensuring the timeliness of the selected target cell with better signal quality, so that the terminal device can quickly select and access the target cell within a certain time period, and the cell provides business services for the terminal device, thereby ensuring the continuity of business transmission.

[0016] In one possible design, if a cell that meets the conditions for adding a primary or secondary cell is not determined within the validity period of the timer, or the timer times out, the terminal device determines the target cell, including: taking a cell that meets the second selection condition among at least one candidate primary or secondary cell as the target cell, and the second selection condition is the S criterion or the signal quality is greater than a second threshold.

[0017] Based on this possible design, when the terminal device cannot select a target cell within the validity period / a certain period of time, the terminal device can use the cell in the candidate PSCell that meets the S criterion or has a signal quality greater than a second threshold as the target cell, that is, the PSCell with better signal quality in the candidate PSCell is used as the target cell, so that the terminal device can access the target cell with better signal quality, and the cell provides the terminal device with relatively high-quality business services, thereby ensuring the continuity of business transmission and unaffected transmission quality.

[0018] In one possible design, the method also includes: the terminal device sends indication information to the network device corresponding to the target cell to indicate that RLF occurs in the first main cell.

[0019] Based on this possible design, the terminal device can send indication information to the source PCell through the selected target cell: the first main network device corresponding to the first main cell, indicating that RLF occurs in the first main cell, so that the first main network device can know that RLF occurs in the first main cell according to the indication information.

[0020] In one possible design, when the terminal device adds the target cell as a target primary and secondary cell, the method also includes: the terminal device receives configuration information for reconfiguring the primary cell from a network device corresponding to the target cell, and the configuration information is configured by the first primary network device.

[0021] Based on this possible design, the main network device corresponding to the source PCell can configure a new main cell for the terminal device, and the terminal device changes the main cell from the first main cell to the new main cell, thereby solving the problem that the terminal device cannot communicate with the first main cell due to RLF in the first main cell.

[0022] In a second aspect, the present application provides a communication device, which may be a terminal or a chip or system on chip in a terminal, or a module or unit in a terminal for implementing the communication method described in an embodiment of the present application. The communication device may implement the functions performed by the terminal in the above-mentioned aspects or possible designs, and the functions may be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-mentioned functions. In one design, the device may include a module corresponding to one of the methods / operations / steps / actions described in the first aspect, and the module may be a hardware circuit, or software, or a combination of a hardware circuit and software. In one design, the communication device may include: a receiving unit, a processing unit;

[0023] A receiving unit, configured to receive, from the first primary network device, CPA information indicating parameters of at least one candidate primary and secondary cell and primary and secondary cell adding condition information of each candidate primary and secondary cell;

[0024] A processing unit is used to detect that an RLF occurs in a first primary cell managed by a first primary network device before determining a cell that meets the conditions for adding a primary or secondary cell based on CPA information, determine a target cell from at least one candidate primary or secondary cell, add the target cell as a target primary or secondary cell, or perform a radio resource control RRC re-establishment process on the target cell, or delete the first primary cell and use the target cell as a second primary cell.

[0025] Among them, the specific implementation method of the communication device can refer to the behavior function of the terminal in the communication method provided by the first aspect or any possible design of the first aspect, and will not be repeated here. Therefore, the provided communication device can achieve the same beneficial effects as the first aspect or any possible design of the first aspect.

[0026] In a third aspect, a communication device is provided, which may be a terminal or a chip or system on chip in the terminal. The communication device may implement the functions performed by the terminal in the above aspects or possible designs, and the functions may be implemented by hardware. In one possible design, the communication device may include: a processor and a communication interface, and the processor may be used to support the communication device to implement the functions involved in the above first aspect or any possible design of the first aspect, for example: the processor is used to receive CPA information indicating the parameters of at least one candidate primary and secondary cell and the primary and secondary cell addition condition information of each candidate primary and secondary cell from the first primary network device through the communication interface, and before determining the cell that meets the primary and secondary cell addition condition according to the CPA information, it is detected that the first primary cell managed by the first primary network device has RLF, and the target cell is determined from at least one candidate primary and secondary cell, and the target cell is added as the target primary and secondary cell, or a radio resource control RRC re-establishment process is performed on the target cell, or the first primary cell is deleted, and the target cell is used as the second primary cell. In another possible design, the communication device may also include a memory, and the memory is used to store computer instructions and / or data. When the communication device is running, the processor executes the computer instructions stored in the memory to enable the communication device to perform the communication method described in the first aspect or any possible design of the first aspect. In an embodiment of the present application, the communication interface can be a transceiver, an interface circuit, a bus interface, a pin or other device capable of realizing a transceiver function.

[0027] In a fourth aspect, a computer-readable storage medium is provided, in which instructions are stored, and when the computer-readable storage medium is executed on a computer, the computer can execute the communication method described in the first aspect or any possible design of the above aspects.

[0028] In a fifth aspect, a computer program product comprising instructions is provided. The computer program product may include program instructions. When the computer program product runs on a computer, the computer can execute the communication method described in the first aspect or any possible design of the above aspects.

[0029] In the sixth aspect, a chip system is provided, the chip system includes a processor and a communication interface, the chip system can be used to implement the functions performed by the terminal in the above-mentioned first aspect or any possible design of the first aspect, for example, the processor is used to receive CPA information indicating the parameters of at least one candidate primary and secondary cell and the primary and secondary cell adding condition information of each candidate primary and secondary cell from the first main network device through the communication interface, and before determining the cell that meets the primary and secondary cell adding condition according to the CPA information, it is detected that the first main cell managed by the first main network device has RLF, and the target cell is determined from at least one candidate primary and secondary cell, and the target cell is added as the target primary and secondary cell, or the radio resource control RRC re-establishment process is performed on the target cell, or the first main cell is deleted and the target cell is used as the second main cell. In one possible design, the chip system also includes a memory, the memory is used to store program instructions and / or data, and when the chip system is running, the processor executes the program instructions stored in the memory, so that the chip system executes the communication method described in the above-mentioned seventh aspect or any possible design of the seventh aspect. The chip system can be composed of a chip, or it can include a chip and other discrete devices, without limitation.

[0030] In the seventh aspect, an embodiment of the present application also provides a communication method, which can be executed by a terminal device, a chip or other apparatus. The method is executed by a terminal device, and the method may include: the terminal device determines a first primary and secondary cell that meets the primary and secondary cell adding conditions from at least one candidate primary and secondary cell according to the CPA information indicating the parameters of at least one candidate primary and secondary cell and the primary and secondary cell adding condition information of each candidate primary and secondary cell received from the first main network device; before the terminal device successfully accesses the first primary and secondary cell, if the terminal device detects that an RLF occurs in the first primary cell managed by the first main network device, the terminal device adds the first primary and secondary cell as the target primary and secondary cell, or determines the target cell and performs an RRC re-establishment process on the target cell, or deletes the first main cell and uses the first main and secondary cell as the second main cell.

[0031] Based on the method described in the seventh aspect, before the terminal device successfully accesses the determined target primary and secondary cells: the first primary and secondary cells, if RLF occurs in the first primary cell, the terminal device selects a cell for RRC re-establishment from the candidate PSCells, and initiates an RRC re-establishment process to the selected target cell. Since the context information of the terminal device has been exchanged between the source PCell and the candidate PSCell, and the service data of the terminal device has been forwarded, the terminal device can quickly re-establish with the selected target cell, reduce the service interruption time between the terminal device and the network device, and ensure the service transmission between the terminal device and the network device in the preparation stage of adding the candidate PSCell. Alternatively, before the terminal device successfully accesses the determined target primary and secondary cell: the first primary and secondary cell, if RLF occurs in the first primary cell, the terminal device uses the first primary and secondary cell as the new primary cell and accesses the first primary and secondary cell. Since the signal quality of the first primary and secondary cell selected from the candidate PSCell is better, and in the candidate SN addition preparation stage, the candidate PSCell has obtained the terminal device context. Therefore, the terminal device can quickly access the first primary and secondary cell, reduce the service interruption time between the terminal device and the network device, and ensure the service transmission between the terminal device and the network device. Alternatively, before the terminal device successfully accesses the determined target primary and secondary cell: the first primary and secondary cell, if RLF occurs in the first primary cell, the terminal device will use the first primary and secondary cell as the target PSCell. Since the signal quality of the first primary and secondary cell that meets the PSCell addition conditions in the candidate PSCell is better, and in the candidate SN addition preparation stage, the candidate PSCell has obtained the terminal device context. Therefore, the terminal device can quickly access the first primary and secondary cell that meets the PSCell addition conditions, and the first primary and secondary cell provides business services for the terminal device, thereby reducing the service interruption time between the terminal device and the network device and ensuring the service transmission between the terminal device and the network device.

[0032] In one possible design, the terminal device determines the target cell, including: the terminal device continues to access the first primary and secondary cell and takes the first primary and secondary cell as the target cell; or, the terminal device stops accessing the first primary and secondary cell and takes a cell that meets the S criterion in at least one candidate primary and secondary cell as the target cell.

[0033] Based on this possible design, the terminal device can use the first primary and secondary cell that meets the PSCell adding conditions as the RRC re-establishment cell, or select a cell that meets the S criterion from the candidate primary and secondary cells as the RRC re-establishment cell. The S criterion selects the target cell, and the signal quality of the selected RRC re-establishment cell is better, so that the terminal device can access the target cell with better signal quality, and the cell provides relatively high-quality business services for the terminal device, ensuring the continuity of business transmission and the transmission quality is not affected.

[0034] In one possible design, the method further includes: the terminal device sends indication information, where the indication information is used to indicate that RLF occurs in the first main cell.

[0035] Based on this possible design, the terminal device can send indication information to the source PCell through the selected target cell: the first main network device corresponding to the first main cell, indicating that RLF occurs in the first main cell, so that the first main network device can know that the terminal device will undergo main cell switching according to the indication information.

[0036] In one possible design, when the terminal device adds the first primary and secondary cell as the target primary and secondary cell, the method also includes: the terminal device receives configuration information from the network device corresponding to the first primary and secondary cell, the configuration information is configured by the first primary network device, and the configuration information is used to reconfigure the primary cell.

[0037] Based on this possible design, the main network device corresponding to the source PCell can configure a new primary cell for the terminal device, without the terminal device selecting a new primary cell through signaling interaction with the network device, thereby reducing the power consumption and signaling interaction caused by the terminal device selecting a new primary cell.

[0038] In an eighth aspect, the present application provides a communication device, which may be a terminal device or a chip or system on chip in a terminal device, or a module or unit in a terminal device for implementing the communication method described in an embodiment of the present application. The communication device may implement the functions performed by the terminal device in the above-mentioned aspects or possible designs, and the functions may be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-mentioned functions. In one design, the device may include a module corresponding to the method / operation / step / action described in the seventh aspect, and the module may be a hardware circuit, or software, or a combination of a hardware circuit and software. In one design, the communication device may include: a processing unit.

[0039] a processing unit, configured to determine, from at least one candidate primary and secondary cell, a first primary and secondary cell that meets the primary and secondary cell adding condition according to the CPA information indicating the parameter of at least one candidate primary and secondary cell and the primary and secondary cell adding condition information of each candidate primary and secondary cell received from the first primary network device;

[0040] The processing unit is also used to detect that an RLF occurs in the first primary cell managed by the first primary network device before the terminal device successfully accesses the first primary secondary cell, add the first primary secondary cell as the target primary secondary cell, or determine the target cell and perform the RRC re-establishment process on the target cell, or delete the first primary cell and use the first primary secondary cell as the second primary cell.

[0041] Among them, the specific implementation method of the communication device can refer to the behavior function of the terminal device in the communication method provided by the seventh aspect or any possible design of the seventh aspect, and will not be repeated here. Therefore, the provided communication device can achieve the same beneficial effects as the seventh aspect or any possible design of the seventh aspect.

[0042] In the ninth aspect, a communication device is provided, which may be a terminal device or a chip or system on chip in the terminal device. The communication device may implement the functions performed by the terminal device in the above aspects or possible designs, and the functions may be implemented by hardware. In one possible design, the communication device may include: a processor and a communication interface, and the processor may be used to support the communication device to implement the functions involved in the above seventh aspect or any possible design of the seventh aspect, for example: the processor is used to determine the first primary and secondary cell that meets the primary and secondary cell addition conditions from at least one candidate primary and secondary cell according to the parameters of at least one candidate primary and secondary cell received from the first primary network device and the CPA information of the primary and secondary cell addition condition information of each candidate primary and secondary cell, and before the terminal device successfully accesses the first primary and secondary cell, if it is detected that the first primary cell managed by the first primary network device has an RLF, the first primary and secondary cell is added as the target primary and secondary cell, or the target cell is determined, and the RRC re-establishment process is performed on the target cell, or the first primary cell is deleted, and the first primary and secondary cell is used as the second primary cell. In another possible design, the communication device may also include a memory, and the memory is used to store computer instructions and / or data. When the communication device is running, the processor executes the computer instructions stored in the memory to enable the communication device to perform the communication method described in the above-mentioned seventh aspect or any possible design of the seventh aspect.

[0043] In the tenth aspect, a computer-readable storage medium is provided, which stores instructions, and when the computer-readable storage medium is run on a computer, the computer can execute the communication method described in the seventh aspect or any possible design of the above aspects.

[0044] In the eleventh aspect, a computer program product comprising instructions is provided. The computer program product may include program instructions. When the computer program product is run on a computer, the computer can execute the communication method described in the seventh aspect or any possible design of the above aspects.

[0045] In the twelfth aspect, a chip system is provided, the chip system includes a processor and a communication interface, the chip system can be used to implement the functions performed by the terminal device in the seventh aspect or any possible design of the seventh aspect, for example, the processor is used to determine the first primary and secondary cell that meets the primary and secondary cell addition condition from at least one candidate primary and secondary cell according to the parameters of at least one candidate primary and secondary cell received from the first main network device and the CPA information of the primary and secondary cell addition condition information of each candidate primary and secondary cell, before the terminal device successfully accesses the first primary and secondary cell, if it is detected that the RLF occurs in the first primary cell managed by the first main network device, the first primary and secondary cell is added as the target primary and secondary cell, or the target cell is determined, and the RRC re-establishment process is performed on the target cell, or the first primary cell is deleted and the first primary and secondary cell is used as the second primary cell. In a possible design, the chip system also includes a memory, the memory is used to store program instructions and / or data, when the chip system is running, the processor executes the program instructions stored in the memory, so that the chip system executes the communication method described in the seventh aspect or any possible design of the seventh aspect. The chip system can be composed of a chip, or it can include a chip and other discrete devices, without limitation.

[0046] In the thirteenth aspect, an embodiment of the present application also provides a communication method, which can be executed by a terminal device, a chip or other apparatus. Taking the method executed by a terminal device as an example, the method includes: the terminal device determines a first primary and secondary cell that meets the primary and secondary cell adding conditions from at least one candidate primary and secondary cell according to CPA information indicating parameters of at least one candidate primary and secondary cell and primary and secondary cell adding condition information of each candidate primary and secondary cell received from the first main network device; if after successfully accessing the first primary and secondary cell, the terminal device detects that RLF occurs in the first main cell, the terminal device deletes the first main cell and determines the first main and secondary cell as the second main cell; or, the terminal device receives configuration information configured by the first main network device through the network device corresponding to the first main and secondary cell, and the configuration information is used to reconfigure the primary cell.

[0047] Based on the method described in aspect 13, after the terminal device successfully accesses the determined target primary and secondary cell: the first primary and secondary cell, if RLF occurs in the first primary cell, the terminal device uses the first primary and secondary cell as the new primary cell and accesses the first primary and secondary cell. Since the signal quality of the first primary and secondary cell selected from the candidate PSCell is better, and in the candidate SN addition preparation stage, the candidate PSCell has obtained the terminal device context, the terminal device can quickly access the first primary and secondary cell, reduce the service interruption time between the terminal device and the network device, and ensure the service transmission between the terminal device and the network device. Alternatively, after the terminal device successfully accesses the determined target primary and secondary cell: the first primary and secondary cell, if RLF occurs in the first primary cell, the terminal device obtains the relevant information of the reconfigured primary cell through the first primary and secondary cell. Since the signal quality of the first primary and secondary cell that meets the PSCell addition conditions in the candidate PSCell is better, the terminal device can quickly obtain the relevant information of the reconfigured primary cell through the first primary and secondary cell, provide service services for the terminal device in the first primary and secondary cell, quickly access the new primary cell, reduce the service interruption time between the terminal device and the network device, and ensure the service transmission between the terminal device and the network device.

[0048] In one possible design, the method also includes: the terminal device sends indication information to a network device corresponding to the first primary and secondary cells, where the indication information is used to indicate that RLF occurs in the first primary cell.

[0049] Based on this possible design, the terminal device can send indication information to the source PCell through the selected first primary and secondary cells: the first primary network device corresponding to the first primary cell, indicating that RLF occurs in the first primary cell, so that the first primary network device can know that the terminal device will undergo primary cell switching according to the indication information.

[0050] In the fourteenth aspect, the present application provides a communication device, which may be a terminal device or a chip or system on chip in the terminal device, or a module or unit in the terminal device for implementing the communication method described in the embodiment of the present application. The communication device can implement the functions performed by the terminal device in the above-mentioned aspects or possible designs, and the functions can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. In one design, the device may include a module corresponding to the method / operation / step / action described in the thirteenth aspect, which may be a hardware circuit, or software, or a combination of a hardware circuit and software. In one design, such as: the communication device may include: a processing unit.

[0051] A processing unit is used to determine a first primary and secondary cell that meets the primary and secondary cell adding conditions from at least one candidate primary and secondary cell according to CPA information indicating parameters of at least one candidate primary and secondary cell and primary and secondary cell adding condition information of each candidate primary and secondary cell received from the first primary network device; if after successfully accessing the first primary and secondary cell, it is detected that RLF occurs in the first primary cell managed by the first primary network device, the first primary cell is deleted, and the first primary and secondary cell is determined as the second primary cell; or, configuration information configured by the first primary network device is received through the network device corresponding to the first primary and secondary cell, and the configuration information is used to reconfigure the primary cell.

[0052] Among them, the specific implementation method of the communication device can refer to the behavioral function of the terminal device in the communication method provided by the thirteenth aspect or any possible design of the thirteenth aspect, and will not be repeated here.

[0053] In the fifteenth aspect, a communication device is provided, which may be a terminal device or a chip or system on chip in the terminal device. The communication device may implement the functions performed by the terminal device in the above aspects or possible designs, and the functions may be implemented by hardware. In one possible design, the communication device may include: a processor and a communication interface, and the processor may be used to support the communication device to implement the functions involved in the above thirteenth aspect or any possible design of the thirteenth aspect, for example: the processor determines the first primary and secondary cell that meets the primary and secondary cell addition conditions from at least one candidate primary and secondary cell according to the parameters indicating at least one candidate primary and secondary cell received from the first primary network device and the CPA information of the primary and secondary cell addition condition information of each candidate primary and secondary cell, if after successfully accessing the first primary and secondary cell, it is detected that the first primary cell managed by the first primary network device has an RLF, delete the first primary cell, and determine the first primary and secondary cell as the second primary cell; or, receive the configuration information configured by the first primary network device through the network device corresponding to the first primary and secondary cell, and the configuration information is used to reconfigure the primary cell. In another possible design, the communication device may also include a memory, and the memory is used to store computer instructions and / or data. When the communication device is running, the processor executes the computer instructions stored in the memory so that the communication device performs the communication method described in the above-mentioned thirteenth aspect or any possible design of the thirteenth aspect.

[0054] In the sixteenth aspect, a computer-readable storage medium is provided, in which instructions are stored. When the computer-readable storage medium is executed on a computer, the computer can execute the communication method described in the above-mentioned thirteenth aspect or any possible design of the thirteenth aspect.

[0055] In the seventeenth aspect, a computer program product comprising instructions is provided. The computer program product may include program instructions. When the computer program product runs on a computer, the computer can execute the communication method described in the thirteenth aspect or any possible design of the thirteenth aspect.

[0056] In the eighteenth aspect, a chip system is provided, the chip system includes a processor and a communication interface, the chip system can be used to implement the functions performed by the terminal device in the above-mentioned thirteenth aspect or any possible design of the thirteenth aspect, for example, the processor determines the first primary and secondary cell that meets the primary and secondary cell addition conditions from at least one candidate primary and secondary cell according to the parameters of at least one candidate primary and secondary cell received from the first main network device and the CPA information of the primary and secondary cell addition condition information of each candidate primary and secondary cell, if after successfully accessing the first primary and secondary cell, it is detected that the first primary cell managed by the first main network device has RLF, delete the first primary cell, and determine the first primary and secondary cell as the second primary cell; or, receive the configuration information configured by the first main network device through the network device corresponding to the first main and secondary cell, and the configuration information is used to reconfigure the primary cell. In a possible design, the chip system also includes a memory, the memory is used to store program instructions and / or data, when the chip system is running, the processor executes the program instructions stored in the memory, so that the chip system executes the communication method described in the above-mentioned thirteenth aspect or any possible design of the thirteenth aspect. The chip system can be composed of a chip, or it can include a chip and other discrete devices.

[0057] In the nineteenth aspect, an embodiment of the present application also provides a communication system, which includes a communication device and a network device as described in any aspect from the second aspect to the sixth aspect; or, includes a communication device and a network device as described in any aspect from the eighth aspect to the twelfth aspect; or, includes a communication device and a network device as described in any aspect from the fourteenth aspect to the eighteenth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1a It is the schematic diagram of EN-DC;

[0059] Figure 1b It is a schematic diagram of NE-DC;

[0060] Figure 1c This is a schematic diagram of NGEN-DC;

[0061] Figure 2 Add a flow chart for SN;

[0062] Figure 3 A schematic diagram of the architecture of a communication system provided in an embodiment of the present application;

[0063] Figure 4 A schematic diagram of the composition of a communication device 400 provided in an embodiment of the present application;

[0064] Figure 5 A flow chart of a communication method provided in an embodiment of the present application;

[0065] Figure 6 A flow chart of a communication method provided in an embodiment of the present application;

[0066] Figure 7 A flow chart of a communication method provided in an embodiment of the present application;

[0067] Figure 8 A schematic diagram of the composition of a communication device 80 provided in an embodiment of the present application;

[0068] Fig. 9 A schematic diagram of the composition of a communication system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0069] First, in order to understand the embodiments of the present application, the terms involved in the embodiments of the present application are described:

[0070] In communication systems, in order to improve the spectrum efficiency and user throughput of the system, carrier aggregation (CA) technology and dual connection (DC) technology are introduced.

[0071] CA is the process of aggregating two or more component carriers (CCs) to form a larger transmission bandwidth. CA is a technology that increases transmission bandwidth and can improve uplink and downlink transmission rates. For example, CA technology can aggregate five 20 MHz CCs to achieve a maximum transmission bandwidth of 100 MHz.

[0072] Among them, one carrier can be called a cell. In the CA scenario, multiple cells can be divided into primary cells (PCell) and secondary cells (SCell) according to the different types of services transmitted on the cells. The secondary cells can also be replaced by primary secondary cells (PSCell). The terminal device can receive public channel information and access the network on the PCell, and can transmit services on the SCell.

[0073] DC means that the terminal device is connected to two network devices at the same time, and the two network devices provide data transmission services for the terminal device at the same time. The two network devices can be a master network device and a secondary network device. The multiple service cells covered by the master network device can form a master cell group (MCG), and the MCG includes a PCell and one or more optional SCells. The master network device is responsible for the control plane and user plane of the terminal device, and can be responsible for sending service data to the terminal device or sending control signaling to the terminal device. The multiple service cells covered by the secondary network device can form a secondary cell group (SCG), and the SCG can include a PSCell and one or more optional SCells. The secondary network device can be responsible for the user plane of the terminal device and send service data to the terminal device. It can be understood that in this application, the network device can be an independent base station (BS) or an evolved node (evolved node B, eNB), or a centralized unit (CU) and / or a distributed unit (DU) or other devices with a protocol stack, etc., without limitation.

[0074] It should be noted that the present application does not limit the radio access technology (RAT) supported by the two network devices to which the terminal device simultaneously accesses, and the RATs supported by the two network devices may be the same or different. RAT may include long term evolution (LTE) technology, new radio (NR) technology, next generation (NG) technology, etc. LTE technology may also replace the UMTS terrestrial radio access (Evolved-UMTS terrestrial radio access, E-UTRA) technology described as evolved. If the two network devices to which the terminal device supporting DC accesses support different RATs, the DC may also be referred to as multiple radio dual connection (MR-DC). In addition, the DC scenario described in the embodiment of the present application is to more clearly illustrate the technical solution of the embodiment of the present application, and does not constitute a limitation on the technical solution provided in the embodiment of the present application. With the evolution of the network architecture, the technical solution provided in the embodiment of the present application is also applicable to application scenarios in which the terminal device supports simultaneous access to more than two or more network devices, and is not limited. Among them, in an application scenario where the terminal device supports simultaneous access to two or more network devices, there is a primary network device among the two or more network devices, and the network devices other than the primary network device among the two or more network devices can be called secondary network devices.

[0075] For example, Figure 1a As shown in the figure, the terminal device supports EN-DC (E-UTRA-NR Dual Connectivity). The terminal device is connected to a base station supporting LTE technology (LTE eNB) and a base station supporting NR technology (gNB). The LTE eNB is the main network device responsible for the user plane and signaling plane of the terminal device, and the gNB is the auxiliary network device responsible for the user plane of the terminal device. Figure 1a As shown in the middle left figure, the LTE eNB is connected to the evolved packet core (EPC). The LTE eNB provides air interface transmission resources for the service data between the terminal device and the EPC, obtains the service data of the terminal device, and transmits the service data of the terminal device to the terminal device through the gNB. Figure 1a As shown in the middle right figure, LTE eNB and gNB are both connected to EPC, and terminal devices can transmit service data between LTE eNB and gNB and EPC.

[0076] For example, Figure 1bAs shown in the figure, the terminal device supports NE-DC (NR-E-UTRA Dual Connectivity). The terminal device is connected to the base station supporting LTE technology: ng-eNB and the base station supporting NR technology: gNB. As the main network device, gNB is responsible for the user plane and signaling plane of the terminal device. As the auxiliary network device, ng-eNB is responsible for the user plane of the terminal device. Figure 1b As shown in the middle left figure, gNB is connected to the fifth-generation core network (5 th generation core, 5GC), gNB provides air interface transmission resources for service data between terminal devices and 5GC, obtains service data of terminal devices, and transmits service data of terminal devices to terminal devices through ng-eNB. Or, Figure 1b As shown in the middle right figure, gNB and ng-eNB are both connected to 5GC, and terminal devices can transmit service data through ng-eNB and between gNB and 5GC.

[0077] For example, Figure 1c As shown in the figure, the terminal device supports NGEN-DC (NG-RAN E-UTRA-NR Dual Connectivity). The terminal device is connected to both the base station supporting LTE technology: ng-eNB and the base station supporting NR technology: gNB. As the main network device, ng-eNB is responsible for the user plane and signaling plane of the terminal device, and as the auxiliary network device, gNB is responsible for the user plane of the terminal device. Figure 1c As shown in the middle left figure, ng-eNB is connected to 5GC. ng-eNB provides air interface transmission resources for service data between terminal devices and 5GC, obtains service data of terminal devices, and transmits service data of terminal devices to terminal devices through gNB. Figure 1c As shown in the middle right figure, both ng-eNB and gNB are connected to 5GC, and terminal devices can transmit service data between ng-eNB and gNB and 5GC.

[0078] In one possible design, SN / PSCell / SCG can be added to the terminal device supporting DC through the SN adding process / PSCell adding process / SCG adding process, and network services can be provided to the terminal device through PCell and PSCell, or through MCG and SCG to improve data transmission performance. In order to improve the reliability or robustness of the PSCell adding process, a conditional PSCell addition (CPA) mechanism is proposed. Figure 2 , is the flow chart of CPA mechanism, such as Figure 2 As shown, this may include:

[0079] Step 201: The first primary network device initiates an SN addition request message to at least one secondary network device, requesting the secondary network device to allocate corresponding wireless resources for the dual connection of the terminal device. The SN addition request message may include the context information of the terminal device, the service data of the terminal device, the measurement result corresponding to the secondary network device for configuring the candidate PSCell, and the necessary security information of the secondary network device, such as: security key, etc.

[0080] Exemplarily, the first main network device that provides network services to the terminal device can trigger the first main network device to send an SN add request message to at least one auxiliary network device based on the measurement report reported by the terminal device and / or when the terminal device requests the first main network device to execute DC.

[0081] Among them, multiple secondary network devices may correspond to one or more candidate target primary and secondary cells or candidate PSCells. Multiple candidate target primary and secondary cells may belong to the same secondary network device or different secondary network devices, without limitation. When the first primary network device and a certain secondary network device are the same network device, that is, when one or some candidate primary and secondary cells and the first primary cell are managed or covered by the same network device (that is, the first primary network device), step 201 may be skipped and not executed. The first primary cell is a cell managed or covered by the first primary network device.

[0082] It should be noted that in each embodiment of the present application, the candidate target primary and secondary cells and the candidate PSCell are equivalent concepts, and the two can be described interchangeably. For example, the candidate target primary and secondary cells can be described interchangeably as candidate PSCells, and the candidate PSCells can be described interchangeably as candidate target primary and secondary cells, etc., without limitation.

[0083] Step 202: Each of the at least one secondary network devices determines whether it accepts the SN adding request message of the first primary network device. If the secondary network device accepts the SN adding request message of the first primary network device, the following process is performed: the secondary network device sends an SN adding request confirmation message to the first primary network device. The SN adding request confirmation message may include the parameters of the candidate PSCell configured by the secondary network device and the primary and secondary cell adding condition information of the candidate PSCell.

[0084] Among them, the parameters of the candidate PSCell may include one or more of the following: the priority of the candidate PSCell, the cell group identifier (cell group Id) corresponding to the candidate PSCell, the cell index corresponding to the candidate PSC (such as: serving cell index (ServCellIndex), the cell radio network temporary identifier (cell-radionetwork temporary identifier, C-RNTI) allocated by the candidate PSCell to the terminal device, the random access channel (random access channel, RACH) resource information required to access the candidate PSCell, the identification information corresponding to the candidate PSC (such as the measurement identifier (measID) corresponding to the candidate PSCell and / or the configuration identification information corresponding to the cell (such as CPA-ConfigId or other representation forms, not limited; the identification information is used to identify the CPA information corresponding to the cell)), the cell global identity (cellglobal identity, CGI) of the candidate PSCell, the physical cell identifier (physical cell identifier, PCI) of the candidate PSC and the frequency information corresponding to the candidate PSC, the physical layer configuration parameters corresponding to the candidate PSC, the media access control (media access control, MAC) layer configuration parameters, and the radio link control (radio link control, RLC) layer configuration parameters, packet data convergence protocol (PDCP) layer configuration parameters, service data adaptation protocol (SDAP) layer configuration parameters, radio resource control (RRC) layer configuration parameters, etc.

[0085] Among them, the primary and secondary cell adding condition information of the candidate PSCell can be used to indicate the primary and secondary cell adding condition that the candidate PSCell needs to meet as the target PSCell to be added, and the primary and secondary cell adding condition information of the candidate PSCell may include the primary and secondary cell adding execution event type and the threshold value corresponding to the primary and secondary cell adding execution event type. Among them, the primary and secondary cell adding execution event type may include A4 event, B1 event or other execution event types. A candidate PSCell may be configured with one or more candidate primary and secondary cell adding conditions. For example, a candidate PSCell may be configured with an execution event type, at least one threshold value and / or at most two different trigger qualities (trigger quantity), which may include reference signal received power (reference signal received power, RSRP), reference signal received quality (reference signal received quality, RSRQ), signal to interference plus noise ratio (signal to interference plus noise ratio, SINR), etc.; or, a candidate PSCell may be configured with at most two different execution event types and threshold values ​​corresponding to each execution event type. It should be noted that the primary and secondary cell addition execution event types and / or threshold values ​​corresponding to the execution event types corresponding to different candidate PSCells may be the same or different, without limitation. As an example, for example, corresponding to the candidate target primary and secondary cell A, the configured primary and secondary cell addition execution event type is an A4 event, and the configured corresponding threshold value is the first threshold value. Then, when the cell signal quality of the candidate target primary and secondary cell A is higher than the first threshold value, it can be considered that the candidate target primary and secondary cell A meets the primary and secondary cell addition conditions (or the candidate target primary and secondary cell A meets the CPA execution conditions), and the candidate target primary and secondary cell A can be determined as the target primary and secondary cell to be added.

[0086] It should be noted that the secondary network device corresponding to the candidate PSCell can also reject the SN addition request message of the first primary network device. At this time, the secondary network device corresponding to the candidate PSCell replies to the first primary network device with an addition request reject response, refusing to configure the candidate PSCell for the terminal device.

[0087] Step 203: The first primary network device receives the SN adding request confirmation message sent by one or more secondary network devices, and sends an RRC reconfiguration message to the terminal device. Correspondingly, the terminal device receives the RRC reconfiguration message.

[0088] The RRC reconfiguration message includes CPA information, and the CPA information includes parameters of at least one candidate PSCell configured by one or more secondary network devices and primary and secondary cell adding condition information of at least one candidate PSCell. For example, the first primary network device can receive SN adding request confirmation messages sent by one or more secondary network devices, obtain the parameters of the candidate PSCell and the primary and secondary cell adding condition information of the candidate PSCell from each SN adding request confirmation message, and carry the obtained parameters of the candidate PSCell and the primary and secondary cell adding condition information of the candidate PSCell in the CPA information.

[0089] Furthermore, the RRC reconfiguration message may also include conditional handover (CHO) configuration information of at least one candidate primary cell, and at least one candidate primary cell may correspond to at least one candidate PSCell, and the candidate primary cell and its corresponding candidate PSCell perform carrier aggregation to form a DC. For example, each cell in at least one candidate primary cell has at least one candidate PSCell corresponding thereto, or a certain cell in at least one candidate primary cell has at least one candidate PSCell corresponding thereto, or some cells in at least one candidate primary cell have at least one candidate PSCell corresponding to each cell in some cells. The CHO configuration information of the candidate primary cell may include parameters of the candidate primary cell and primary cell handover condition information of the candidate primary cell. The terminal device may perform a CHO process according to the CHO configuration information of the candidate primary cell, for example, determining a cell in the candidate primary cell that meets the primary cell handover condition as a target primary cell, and then the terminal device attempts to switch to the target primary cell.

[0090] That is, in one possible implementation, the RRC reconfiguration message may include relevant information of at least one candidate PSCell (such as CPA information). In another possible implementation, the RRC reconfiguration message may include relevant information of at least one candidate primary cell (such as CHO configuration information) and relevant information of at least one candidate PSCell corresponding to at least one candidate primary cell (such as CPA information). For example, assuming that the candidate primary cell cell1 corresponds to the candidate PSCells: cellC, cellD (or, the candidate primary cell cell1 can be carrier aggregated with the candidate PSCell (such as cellC or cellD) to form a DC), and the candidate primary cell cell2 corresponds to the candidate PSCells: cellE, cellF (or, the candidate primary cell cell2 can be carrier aggregated with the candidate PSCell (such as cellE or cellF) to form a DC), the RRC reconfiguration message includes: parameters of cell1 and primary cell switching condition information of cell1, parameters of cellC corresponding to cell1 and primary and secondary cell adding condition information of cellC, parameters of cellD corresponding to cell1 and primary and secondary cell adding condition information of cellD, parameters of cell2 and primary cell switching condition information of cell2, parameters of cellE corresponding to cell2 and primary and secondary cell adding condition information of cellE, parameters of cellF corresponding to cell2 and primary and secondary cell adding condition information of cellF.

[0091] It should be noted that the first main network device can carry all the parameters of the candidate PSCells sent by all the secondary network devices it has received and the primary and secondary cell adding condition information of the candidate PSCells in one RRC reconfiguration message and send it to the terminal device, or the first main network device sends at least two RRC reconfiguration messages to the terminal device, each RRC reconfiguration message carries the parameters of the candidate PSCells sent by at least one secondary network device and the primary and secondary cell adding condition information of the candidate PSCell, without restriction.

[0092] Step 204: The terminal device replies with an RRC reconfiguration completion message to the first master network device.

[0093] Among them, step 204 is an optional step, and the execution order of step 204 is not limited. Step 204 can be executed before step 206 or step 207, or after step 206 or step 207, or simultaneously with step 206 or step 207, without limitation.

[0094] Step 205: The terminal device determines whether the primary and secondary cell adding conditions of at least one candidate PSCell are met according to the CPA information carried in the received RRC reconfiguration message.

[0095] Exemplarily, for each candidate PSCell, the terminal device can determine whether the candidate PSCell satisfies the conditions for adding primary and secondary cells, including: the terminal device determines whether the measurement result corresponding to each trigger quality among at least one trigger quality of the PSCell satisfies the conditions for adding primary and secondary cells corresponding to the trigger quality in the CPA information; if so, it is determined that the candidate PSCell satisfies the conditions for adding primary and secondary cells.

[0096] For example, taking the candidate primary and secondary cell A configured with the primary and secondary cell adding execution event type of A4 event, and configured with two trigger quantities: RSRP and RSRQ, the configured corresponding RSRP threshold value is E, and the configured corresponding RSRQ threshold value is F as an example, when the terminal device measures that the RSRP of the candidate primary and secondary cell A is higher than E, and the RSRQ of the candidate primary and secondary cell A is higher than F, the terminal device can determine that the candidate primary and secondary cell A meets the primary and secondary cell adding conditions; otherwise, it is determined that the candidate primary and secondary cell A does not meet the primary and secondary cell adding conditions.

[0097] Step 206: The terminal device determines a candidate PSCell that meets the primary and secondary cell adding conditions as the target primary and secondary cell.

[0098] Among them, when the RRC reconfiguration message does not contain CHO configuration information but includes CPA information, the terminal device judges whether at least one candidate PSCell meets the conditions for adding primary and secondary cells based on the CPA information, and selects a candidate PSCell that meets the conditions for adding primary and secondary cells among at least one candidate PSCell as the target primary and secondary cell.

[0099] In the case where the RRC reconfiguration message includes CHO configuration information and CPA information, before the terminal device determines whether the candidate PSCell satisfies the primary and secondary cell adding condition, it can select a target primary cell that satisfies the primary cell switching condition from the candidate primary cells according to the CHO configuration information, and then determine whether the candidate PSCell corresponding to the target primary cell satisfies the primary and secondary cell adding condition according to the CPA information of the candidate PSCell, and select a candidate PSCell that satisfies the primary and secondary cell adding condition from the candidate PSCell corresponding to the target primary cell as the target primary and secondary cell. For example, taking the example in step 203 as an example, if the determined target primary cell is cell1, since the relevant information (such as CPA information) of at least one candidate PSCell corresponding to the target primary cell cell1 is the CPA information of cellC and cellD, that is, the parameters of cellC and the primary and secondary cell adding condition information of cellC, the parameters of cellD and the primary and secondary cell adding condition information of cellD, the terminal device determines the target primary and secondary cell from cellC and cellD, that is, the terminal device determines the cell that satisfies the primary and secondary cell adding condition among cellC and cellD as the target primary and secondary cell. Or, for example, if the determined target primary cell is cell1, if the network device configures a target primary and secondary cell for the target main cell cell1, that is, the RRC reconfiguration message includes not only relevant information of cell1 (such as the CHO configuration information corresponding to cell1), but also relevant information of the target primary and secondary cells corresponding to cell1 (such as configuring cellK as the target primary and secondary cell, that is, also including the parameters of cellK), then the terminal device adds cellK as the target primary and secondary cell.

[0100] Step 207: The terminal device initiates a random access process to the target primary and secondary cells. After the terminal device successfully accesses the target primary and secondary cells, the terminal device sends an RRC reconfiguration completion message to the network device to which the target primary and secondary cells belong. Subsequently, the terminal device can perform data transmission with the network device through the target primary and secondary cells.

[0101] It should be noted that the present application does not limit the execution order of each step in the embodiment, and the order of each step can be flexibly changed. In addition, each step in the embodiment of the present application is an optional execution step, and each step can be executed separately or in combination without limitation.

[0102] Although the reliability / robustness of the PSCell / SN adding process can be improved by the CPA mechanism, when the terminal device executes the SN adding process, such as: in the process of determining whether the candidate primary and secondary cells meet the primary and secondary cell adding conditions, or before determining the target primary and secondary cells that meet the primary and secondary cell adding conditions, that is, before step 206; or, after the terminal device determines the target primary and secondary cells to be added but before successfully accessing the target primary and secondary cells; or, after the terminal device successfully accesses the determined target primary and secondary cells, if the terminal device finds that the first primary cell has RLF, that is, the connection between the terminal device and the first primary network device corresponding to the first primary cell is interrupted, then in order to continue the transmission of service data, the terminal device needs to initiate the RRC re-establishment process. At this time, if the re-established cell does not have the context information of the terminal device, the re-established cell needs to obtain the context information of the terminal device from the first primary network device corresponding to the first primary cell, and obtain the data packets that have not been successfully transmitted between the terminal device and the first primary network device from the first primary network device corresponding to the first primary cell, and send them to the terminal device. This process will cause a long service interruption delay.

[0103] To solve this technical problem, the embodiment of the present application provides a communication method: before determining the target primary and secondary cells that meet the conditions for adding primary and secondary cells, that is, before step 206; if RLF occurs in the first primary cell, the terminal device selects a target cell from at least one candidate PSCell according to a certain criterion, adds the target cell as the target primary and secondary cell, or uses the target cell as an RRC re-establishment cell, performs an RRC re-establishment process on the target cell, or deletes / releases the first primary cell, and uses the target cell as a new primary cell for access. Specifically, the execution process can refer to the following Figure 5 As described in the corresponding embodiments.

[0104] Alternatively, after the terminal device determines the target primary and secondary cell to be added but before successfully accessing the target primary and secondary cell, if RLF occurs in the first primary cell, then, in one approach, the terminal device continues to access the determined target primary and secondary cell; or, in another approach, the terminal device stops accessing the determined target primary and secondary cell, selects a target cell to be re-established from the candidate PSCell, and performs the RRC re-establishment process on the target cell; or, in another approach, the terminal device deletes / releases the first primary cell, or releases the connection with the first primary cell, and uses the target primary and secondary cell as the new primary cell. Specifically, the execution process can refer to the following Figure 6 As described in the corresponding embodiments.

[0105] Alternatively, after the terminal successfully accesses the determined target primary and secondary cells, if RLF occurs in the first primary cell, the terminal device deletes / releases the first primary cell, or releases the connection with the first primary cell, and determines the target primary and secondary cell as the new primary cell; or, the terminal device receives the configuration information of the new primary cell configured by the first primary network device corresponding to the first primary cell from the target primary and secondary cell, establishes a connection with the new primary cell according to the configuration information, and resumes service data transmission. Specifically, the execution process can refer to the following Figure 7 As described in the corresponding embodiments.

[0106] The communication method provided in the embodiment of the present application is described below in conjunction with the drawings of the specification.

[0107] The communication method provided in the embodiment of the present application can be applied to various communication systems supporting DC, such as: long term evolution (LTE) system, fifth generation (5G) mobile communication system, wireless fidelity (WiFi) system, future communication system, or a system integrating multiple communication systems, etc., which is not limited in the embodiment of the present application. Among them, 5G can also be called new radio (NR).

[0108] The communication method provided in the embodiments of the present application can be applied to various communication scenarios, for example, it can be applied to one or more of the following communication scenarios: enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), machine type communication (MTC), massive machine type communication (mMTC), device to device (D2D), vehicle to everything (V2X), vehicle to vehicle (V2V), and Internet of things (IoT), etc.

[0109] Below Figure 3 Taking the communication system shown as an example, the communication method provided in the embodiment of the present application is described.

[0110] Figure 3 is a schematic diagram of a communication system provided in an embodiment of the present application, such as Figure 3As shown, the communication system may include a network device and multiple terminal devices, and the terminal device may be a terminal device supporting DC, wherein the network device includes an access network device, and may also include a core network device, and may also include a service provider's device (such as a server), etc., without limitation. The embodiment of the present application is described by taking the network device as an access network device as an example. The RATs supported by different access network devices may be the same or different, and the access network devices communicate with each other through a wired network or a wireless network, for example, through Figure 3 The Xn interfaces in the communication network communicate with each other. The access network device can cover one or more cells, such as: access network device 1 covers cell 1.1, access network device 2 covers cell 2.1, and access network device covers cell 3.1. A terminal device that supports DC can access the access network device in one of the cells and set the access network device as the main network device, such as: terminal device 1 can access access network device 1 in cell 1.1 and use access network device 1 as the main network device, i.e., masternode (MN). Subsequently, in order to improve the reliability of the service data of terminal device 1, access network device 1 can refer to the above Figure 2 The method shown obtains CPA information including parameters of one or more candidate PSCells (such as cell 2.1, cell 3.1) and primary and secondary cell adding condition information of each PSCell, and configures the obtained CPA information to terminal device 1. Terminal device 1 can determine whether each PSCell in one or more candidate PSCells meets the primary and secondary cell adding condition, select one or more candidate PSCells that meet the primary and secondary cell adding condition (such as cell 3.1) to add as the target primary and secondary cell, and access the target primary and secondary cell to achieve DC communication. If RLF occurs between terminal device 1 and access network device 1 during the process of adding PSCell, terminal device 1 can refer to Figure 5 to Figure 7 The method shown selects a target cell and accesses the target cell to resume service transmission.

[0111] It should be noted that Figure 3 This is just an exemplary framework diagram. Figure 3 The number of nodes, number of cells and status of terminal devices included in the Figure 3 In addition to the functional nodes shown, other nodes may also be included, such as core network equipment, gateway equipment, application servers, etc., without limitation. The access network equipment communicates with the core network equipment through a wired network or a wireless network, such as through a next generation (NG) interface.

[0112] Among them, the network equipment is mainly used to implement functions such as resource scheduling, wireless resource management, and wireless access control of terminal equipment. Specifically, the network equipment may include any of a base station, a wireless access point, a transmission receive point (TRP), a transmission point (TP), and some other access nodes. In the embodiment of the present application, the device for implementing the function of the network device may be a network device; it may also be a device that can support the network device to implement the function, such as a chip system, which can be installed in the network device or used in combination with the network device. In the technical solution provided in the embodiment of the present application, the technical solution provided in the embodiment of the present application is described by taking the device for implementing the function of the network device as a network device as an example.

[0113] The terminal equipment may be a terminal, a user equipment (UE), a mobile station (MS) or a mobile terminal (MT), etc. Specifically, the terminal equipment may be a mobile phone, a tablet computer or a computer with a wireless transceiver function, or a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in unmanned driving, a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in a smart city, a smart home, or a vehicle-mounted terminal, etc. In the embodiment of the present application, the device for realizing the function of the terminal device may be a terminal device, or may be a device that can support the terminal device to realize the function, such as a chip system, which may be installed in the terminal device or used in combination with the terminal device. The following takes the device for realizing the function of the terminal device as an example to describe the communication method provided in the embodiment of the present application.

[0114] In the specific implementation, Figure 3 The network elements shown, such as terminal equipment and network equipment, can be used Figure 4 The structure shown may include Figure 4 Parts shown. Figure 4 A schematic diagram of the structure of a communication device 400 provided in an embodiment of the present application. When the communication device 400 has the function of the terminal device described in the embodiment of the present application, the communication device 400 may be a terminal device or a chip or system on chip in the terminal device. When the communication device 400 has the function of the network device described in the embodiment of the present application, the communication device 400 may be a network device or a chip or system on chip in the network device.

[0115] like Figure 4 As shown, the communication device 400 may include a processor 401, a communication line 402, and a communication interface 403. Further, the communication device 400 may also include a memory 404. The processor 401, the memory 404, and the communication interface 403 may be connected via a communication line 402.

[0116] The processor 401 may be a central processing unit (CPU), a general-purpose processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 401 may also be other devices with processing functions, such as circuits, devices, or software modules.

[0117] The communication line 402 is used to transmit information between the components included in the communication device 400.

[0118] The communication interface 403 is used to communicate with other devices or other communication networks. The other communication networks may be Ethernet, radio access network (RAN), wireless local area network (WLAN), etc. The communication interface 403 may be an interface circuit, a pin, a radio frequency module, a transceiver, or any device capable of achieving communication.

[0119] The memory 404 is used to store instructions, where the instructions may be computer programs.

[0120] Among them, the memory 404 can be a read-only memory (ROM) or other types of static storage devices that can store static information and / or instructions, or a random access memory (RAM) or other types of dynamic storage devices that can store information and / or instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage, magnetic disk storage medium or other magnetic storage device, and the optical disc storage includes a compressed optical disc, a laser disc, an optical disc, a digital versatile disc, or a Blu-ray disc, etc.

[0121] It should be noted that the memory 404 can exist independently of the processor 401, or can be integrated with the processor 401. The memory 404 can be used to store instructions or program codes or some data, etc. The memory 404 can be located in the communication device 400, or can be located outside the communication device 400, without limitation. The processor 401 is used to execute the instructions stored in the memory 404 to implement the communication method provided in the following embodiments of the present application.

[0122] In one example, the processor 401 may include one or more CPUs, such as Figure 4 CPU0 and CPU1 in.

[0123] As an optional implementation, the communication device 400 includes multiple processors, for example, Figure 4 In addition to the processor 401, a processor 407 may also be included.

[0124] As an optional implementation, the communication device 400 further includes an output device 405 and an input device 406. Exemplarily, the input device 406 is a device such as a keyboard, a mouse, a microphone or a joystick, and the output device 405 is a device such as a display screen and a speaker.

[0125] It should be noted that the communication device 400 can be a desktop computer, a portable computer, a network server, a mobile phone, a tablet computer, a wireless terminal device, an embedded device, a chip system or a Figure 4 In addition, Figure 4 The structure shown in the figure does not constitute a limitation on the communication device, except Figure 4 In addition to the components shown, the communication device may include more or fewer components than shown, or combine certain components, or arrange the components differently.

[0126] In the embodiment of the present application, the chip system may be composed of a chip, or may include a chip and other discrete devices.

[0127] Combine the following Figure 3 The communication system shown in the figure describes the communication method provided in the embodiment of the present application. Among them, each device in the following embodiment may have Figure 4 The components shown. Among them, the actions, terms, etc. involved in the various embodiments of the present application can refer to each other without limitation. The message name or parameter name in the message exchanged between the various devices in the embodiments of the present application is only an example, and other names can also be used in the specific implementation without limitation.

[0128] Figure 5 A flow chart of a communication method provided in an embodiment of the present application, such as Figure 5As shown, the method includes:

[0129] Step 501: The terminal device receives CPA information from the first main network device.

[0130] The terminal device can be Figure 3 Any terminal device that supports MR-DC in the system shown, such as: The terminal device can be Figure 3 The system shown is a terminal device 1 that supports MR-DC.

[0131] Among them, the CPA information may indicate the parameters of at least one candidate primary and secondary cell and the primary and secondary cell adding condition information of each candidate primary and secondary cell, and at least one candidate primary and secondary cell may refer to one candidate primary and secondary cell or two or more candidate primary and secondary cells. Specifically, the description of the CPA information, the parameters of the candidate primary and secondary cells, and the primary and secondary cell adding condition information of the candidate primary and secondary cells can refer to the above Figure 2 For example, taking the candidate PSCells including cell 2.1, cell 3.1, and cell 4.1 as an example, the CPA information received by the terminal device from the main network device includes {parameters of cell 2.1, primary and secondary cell adding condition information of cell 2.1}, {parameters of cell 3.1, primary and secondary cell adding condition information of cell 3.1}, and {parameters of cell 4.1, primary and secondary cell adding condition information of cell 4.1}.

[0132] Exemplarily, the terminal device may receive an RRC reconfiguration message carrying CPA information from the first primary network device, and obtain the CPA information from the RRC reconfiguration message. Specifically, the primary network device may request the network device to which at least one candidate primary and secondary cell belongs to obtain the CPA information of at least one candidate primary and secondary cell, and the primary network device may send an RRC reconfiguration message carrying CPA information to the terminal device. The execution process of the terminal device obtaining the RRC reconfiguration message may refer to the above steps 201 to 204, and will not be repeated here.

[0133] Step 502: before determining a cell that meets the conditions for adding a primary or secondary cell according to CPA information, the terminal device detects that an RLF occurs in the first primary cell.

[0134] The first primary cell may be a source primary cell of the terminal device or a cell belonging to the source MCG, the first primary cell may be a cell managed by the first primary network device, and the first primary network device may provide services for the terminal device in the first primary cell. Figure 3 For example, the first primary cell can be Figure 3 In the cell 1.1, the first main network device may be access network device 1.

[0135] The occurrence of RLF in the first primary cell may refer to the failure of normal data transmission between the terminal device and the first primary cell or the first primary network device, such as failure of uplink data transmission and / or downlink data transmission. Figure 3 Taking the terminal device 1 in the example, where the first main cell is cell 1.1 and the first main network device is access network device 1, the terminal device detects that RLF occurs in the first main cell, which may mean that the connection between the terminal device 1 and the cell 1.1 is disconnected, or the terminal device cannot transmit data with the access network device 1, and cannot receive the service data and configuration information sent by the access network device 1.

[0136] In the present application, before the terminal device determines the cell that meets the primary and secondary cell adding conditions according to the CPA information, it may include: the terminal device determines whether the primary and secondary cell adding conditions of at least one candidate primary and secondary cell are met according to the CPA information; or the terminal device determines whether at least one candidate primary cell meets the primary cell switching conditions according to the CHO configuration information.

[0137] Exemplarily, the terminal device may determine that an RLF occurs in the first main cell in the following manner: if the terminal device continuously detects a preset number of out-of-sync occurrences in the physical layer, the terminal device determines that an RLF occurs in the first main cell; or, if the terminal device has not received the service data sent by the first main network device within a preset time period, the terminal device determines that an RLF occurs in the first main cell; or, if the number of failures of the terminal device to send service data to the first main network device within a preset time period is greater than or equal to a preset number of failures, the terminal device determines that an RLF occurs in the first main cell.

[0138] Among them, the preset time, preset number of failures, and preset number can be set as needed, and can be agreed upon in the protocol or configured by the network device without restriction.

[0139] Step 503: The terminal device determines a target cell from at least one candidate primary and secondary cell, adds the target cell as a target primary and secondary cell, or performs an RRC re-establishment process on the target cell, or deletes / releases the first primary cell and uses the target cell as a second primary cell.

[0140] The target cell may be a candidate primary and secondary cell that satisfies the S criterion or the first selection condition or the second selection condition in at least one candidate primary and secondary cell. The target cell may be used as a target primary and secondary cell to be added or used for RRC reestablishment or replacement of the original first primary cell as a new primary cell.

[0141] Specifically, the terminal device determines the target cell from at least one candidate primary and secondary cell and processes the target cell, which may include the following steps: Figure 5In any of the three branches shown, the first branch includes step 5031a and step 5032a; the second branch includes step 5031b to step 5034b; and the third branch may include step 5031c to step 5033c. Specifically, which of the three branches the terminal device uses to determine the target cell may be pre-configured or specified by the protocol, or the network device may instruct the terminal device which branch to use.

[0142] Step 5031a: The terminal device selects a cell that meets the S criterion among at least one candidate primary and secondary cells as a target cell.

[0143] The S criterion may be used to select a cell for RRC re-establishment. It should be noted that the S criterion may also be replaced by other criteria capable of selecting a cell for RRC re-establishment, without limitation.

[0144] Exemplarily, the terminal device taking a cell satisfying the S criterion among at least one candidate primary and secondary cells as a target cell may include: the terminal device determines whether at least one candidate primary and secondary cell satisfies the S criterion, and obtains one or more cells satisfying the S criterion; if there is one cell satisfying the S criterion, the cell satisfying the S criterion is taken as the target cell; if there are multiple cells satisfying the S criterion, any one cell is selected from the multiple cells satisfying the S criterion as the target cell; or, a cell satisfying any one or more of the following conditions among the multiple cells satisfying the S criterion is taken as the target cell: the highest priority, the best (or highest) signal quality, the smallest or largest corresponding cell index, the smallest or largest corresponding configuration identification information (such as CPA-ConfigId or other identification forms); or, the first cell satisfying the S criterion, etc.

[0145] For example, taking the candidate PSCells including cell 2.1, cell 3.1, and cell 4.1 as an example, wherein the candidate PSCells that meet the S criterion include {cell 2.1, cell 4.1}, the terminal device can use any candidate PSCell in {cell 2.1, cell 4.1}: cell 2.1 or cell 4.1 as the target cell; or, the terminal device can use the cell with a higher priority in {cell 2.1, cell 4.1} as the target cell; or, the terminal device can use the cell with the highest cell signal quality in {cell 2.1, cell 4.1} as the target cell; or, the terminal device can use the cell that meets the S preparation that is detected first in {cell 2.1, cell 4.1} as the target cell.

[0146] Step 5032a: The terminal device uses the target cell as the RRC re-establishment cell and performs the RRC re-establishment process on the target cell.

[0147] Exemplarily, the RRC re-establishment process performed by the terminal device on the target cell may include:

[0148] The terminal device sends an RRC reestablishment request (RRC restablishment request) message to the target cell, where the RRC reestablishment request message may be used to request establishment of an RRC connection between the network device corresponding to the target cell;

[0149] If the network device corresponding to the target cell accepts the RRC re-establishment request message sent by the terminal device, the network device corresponding to the target cell sends an RRC re-establishment message (RRC re-establishment) to the terminal device;

[0150] The terminal device receives the RRC re-establishment message and establishes an RRC connection with the network device corresponding to the target cell. After the terminal device establishes the RRC connection with the network device corresponding to the target cell, it sends an RRC re-establishment completion message to the network device corresponding to the target cell.

[0151] Further optionally, when step 5031a is started, the terminal device may stop / no longer determine whether the primary and secondary cell adding condition of at least one candidate primary and secondary cell is met to reduce the power consumption of the terminal device. Alternatively, the terminal device may continue to determine whether the primary and secondary cell adding condition of at least one candidate primary and secondary cell is met without restriction.

[0152] Further optionally, after the terminal device stops / no longer determines whether the primary and secondary cell adding condition of at least one candidate primary and secondary cell is satisfied, the terminal device deletes the CPA information.

[0153] Further optionally, the terminal device sends indication information to the network device corresponding to the target cell, and the indication information can be used to indicate that RLF occurs in the first primary cell. Optionally, the indication information can include at least one of the following: identification information of the first primary cell, indication information that RLF occurs in the first primary cell, signal quality of the first primary cell, signal quality of at least one candidate primary and secondary cell, etc.; after receiving the indication information, the network device corresponding to the target cell can send a first message to the first primary network device, and the first message is used to notify the first primary network device that RLF occurs in the first primary cell. Optionally, the first message can include indication information that RLF occurs in the first primary cell, or the first message can include at least one of the above indication information. After receiving the first message, the first primary network device disconnects from the terminal device, no longer provides network services to the terminal device, and no longer transmits service data with the terminal device.

[0154] In the present application, the identification information of the first primary cell can be used to identify the first primary cell. Exemplarily, the identification information of the first primary cell can be at least one of the following: a physical cell identifier (PCI), frequency information, a cell global identifier (CGI), and a cell radio network temporary (C-RNTI).

[0155] In this way, before the target primary and secondary cells are determined, in the scenario where RLF occurs in the first primary cell, the terminal device can select a target cell to be re-established from the candidate primary and secondary cells, and initiate an RRC re-establishment process to the selected target cell. Since the context information of the terminal device has been exchanged and the service data of the terminal device has been forwarded between the source PCell (i.e., the first primary cell) and each candidate primary and secondary cell in at least one candidate PSCell during the preparation stage for adding the candidate PSCell, the network device corresponding to the target cell (the target cell is one of the at least one candidate primary and secondary cells) can quickly re-establish the RRC connection and transmit service data with the terminal device based on the context information of the terminal device, thereby reducing the service interruption time between the terminal device and the network device and ensuring the service transmission between the terminal device and the network device.

[0156] Step 5031b: The terminal device determines whether there is a cell that meets the first selection condition in at least one candidate primary and secondary cell. If there is a cell that meets the first selection condition, step 5032b or step 5033b is executed and the process ends; if not, step 5034b is executed and the process ends.

[0157] The first selection condition may be used to select a target primary and secondary cell to be added or a new primary cell, and the first selection condition may include a primary and secondary cell addition condition or a signal quality greater than a first threshold. Each of the at least one candidate primary and secondary cell may correspond to a first selection condition, and the first selection conditions corresponding to different candidate primary and secondary cells may be the same or different.

[0158] The primary and secondary cell adding condition included in the first selection condition can be indicated to the terminal device through the primary and secondary cell adding condition information included in the CPA information. The first threshold can be set as needed, and the first threshold can be the same as or different from the threshold value in the primary and secondary cell adding condition information of the candidate primary and secondary cell. The first threshold can be agreed upon by the protocol, or sent by the first primary network device to the terminal device, which is not limited.

[0159] The signal quality described in this embodiment may include one or more of RSRP, RSRQ and SINR.

[0160] For example, taking the case where the candidate PSCells include cell 2.1 and cell 3.1, and the CPA information includes {parameters of cell 2.1, information on adding conditions for the primary and secondary cells of cell 2.1 (e.g., A4 event, threshold value E corresponding to RSRP)}, and {parameters of cell 3.1, information on adding conditions for the primary and secondary cells of cell 3.1 (e.g., A4 event, threshold value F corresponding to RSRQ)}, the first selection condition corresponding to cell 2.1 may be "the RSRP of the cell is greater than E" or the RSRP of the cell is greater than a first threshold value, the first threshold value may be a positive number or "0", and the first threshold value may be the same as or different from E. The first selection condition corresponding to cell 3.1 may be "the RSRQ of the cell is greater than F" or "the RSRQ of the cell is greater than the first threshold value", the first threshold value may be a positive number or "0", and the first threshold value may be the same as or different from F.

[0161] Exemplarily, if the first selection condition includes a primary and secondary cell adding condition, the terminal device determines whether there is a cell that meets the first selection condition in at least one candidate primary and secondary cell, which may include: the terminal device determines whether the signal quality of one or some candidate primary and secondary cells in at least one candidate primary and secondary cell is higher than the threshold value indicated by the primary and secondary cell adding condition information; if the signal quality of a certain candidate primary and secondary cell is higher than the threshold value indicated by the primary and secondary cell adding condition information, the candidate primary and secondary cell can be determined as a cell that meets the first selection condition; otherwise, it can be determined that the candidate primary and secondary cell does not meet the first selection condition.

[0162] If the first selection condition includes that the signal quality is greater than the first threshold, the terminal device may determine whether there is a cell that meets the first selection condition in at least one candidate primary and secondary cell, which may include: determining whether the signal quality of one or some of the at least one candidate primary and secondary cells is higher than the first threshold; if the signal quality of a candidate primary and secondary cell is higher than the first threshold, the candidate primary and secondary cell may be determined as a cell that meets the first selection condition; otherwise, it may be determined that the candidate primary and secondary cell does not meet the first selection condition.

[0163] It should be noted that, in the present application, the candidate primary and secondary cells satisfying the first selection condition in the at least one candidate primary and secondary cell may be one or more.

[0164] Further optionally, when step 5031b is started, if the first selection condition is that the signal quality is greater than the first threshold, and the first threshold is different from the corresponding threshold value in the primary and secondary cell adding condition information of the candidate primary and secondary cells, the terminal device can stop / no longer determine whether at least one candidate primary and secondary cell meets the primary and secondary cell adding condition to reduce the power consumption of the terminal device, and further optionally, the terminal device can delete / release the CPA information. Alternatively, the terminal device can also continue to determine whether at least one candidate primary and secondary cell meets the primary and secondary cell adding condition without restriction.

[0165] Step 5032b: The terminal device selects the cell that meets the first selection condition as the target cell, and adds the target cell as a target primary and secondary cell.

[0166] Exemplarily, in the present application, the terminal device takes the cell that meets the first selection condition as the target cell, which may include: if there is one cell that meets the first selection condition, then the cell that meets the first selection condition is taken as the target cell; if there are multiple cells that meet the first selection condition, then any one cell is selected from the multiple cells that meet the first selection condition as the target cell; or, the cell that meets any one or more of the following conditions among the multiple cells that meet the first selection condition is taken as the target cell: the highest priority, the best / highest signal quality, the maximum or minimum corresponding cell index, the minimum or maximum corresponding configuration identification information (such as CPA-ConfigId or other identification form); or, the first cell that meets the first selection condition, etc.

[0167] Exemplarily, the terminal device adding the target cell as a target primary and secondary cell may include: the terminal device uses / applies the parameters of the target cell contained in the CPA information, the terminal device initiates a random access process to the target cell to attempt to access the target cell, and after successfully accessing the target cell, data transmission can be performed with the target cell.

[0168] Among them, the parameters of the target cell can refer to the above description of "parameters of at least one candidate primary and secondary cell", which will not be repeated here.

[0169] Further optionally, after the terminal device successfully accesses the target cell / target primary and secondary cell, the terminal device sends indication information to the network device corresponding to the target primary and secondary cell to indicate that RLF occurs in the first primary cell. Optionally, the indication information may include at least one of the following: identification information of the first primary cell, indication information that RLF occurs in the first primary cell, signal quality of the first primary cell, signal quality of at least one candidate primary and secondary cell, etc.; after receiving the indication information, the network device corresponding to the target primary and secondary cell may send a second message to the first primary network device, and the second message is used to notify the first primary network device that RLF occurs in the first primary cell. The second message may include indication information that RLF occurs in the first primary cell, or the second message may include at least one of the above indication information.

[0170] Further optionally, after receiving the second message, the first main network device disconnects from the terminal device, no longer provides network services to the terminal device, and no longer transmits service data with the terminal device. Optionally, after receiving the second message, the first main network device reconfigures a new primary cell. For example, the first main network device can configure a new primary cell for the terminal device to replace the first primary cell, or the first main network device can configure a new primary cell to be switched to for the terminal device, and the new primary cell is not the same cell as the first primary cell. After the first main network device determines the configuration information corresponding to the new main cell or the new main cell, in one implementation method, the first main network device can send the configuration information corresponding to the new main cell to the target main and auxiliary cells or the network device to which the target main and auxiliary cells belong (for example, the first main network device can send the PDCP SDU corresponding to the above configuration information to the target main and auxiliary cells or the network device to which the target main and auxiliary cells belong), and then the network device to which the target main and auxiliary cells belong can send the configuration information corresponding to the new main cell to the terminal device through its own SRB3, or, in another implementation method, the first main network device can send the configuration information corresponding to the new main cell to the target main and auxiliary cells or the network device to which the target main and auxiliary cells belong through split SRB1 (for example, the first main network device can send the PDCP PDU or RLC SDU corresponding to the above configuration information to the target main and auxiliary cells or the network device to which the target main and auxiliary cells belong), and then the network device to which the target main and auxiliary cells belong can send the configuration information corresponding to the new main cell to the terminal device. The configuration information corresponding to the new main cell can be determined by the first main network device. Optionally, the first main network device may consider that a late CPA has occurred based on the second message received, and subsequent main network devices (such as the first main network device or the network device to which at least one candidate primary and secondary cell belongs) may adjust the CPA information to avoid late CPA as much as possible. For example, by adjusting the CPA information, the terminal device can successfully access the cell that meets the conditions for adding the primary and secondary cells or successfully complete the SN / SCG / PSCell addition process, thereby avoiding RLF in the first main cell or the first main network device before the SN / SCG / PSCell addition process is completed.

[0171] It can be understood that after the first main network device receives the second message, it can configure a new main cell for the terminal device, such as: the first main network device sends configuration information to the network device corresponding to the target main and auxiliary cells, and the configuration information can be used to reconfigure the main cell; after the network device corresponding to the target main and auxiliary cells receives the configuration information, it sends the configuration information to the terminal device; after the terminal device receives the configuration information, it attempts to change the main cell from the first main cell to the new main cell indicated in the configuration information according to the configuration information.

[0172] Step 5033b: The terminal device selects the cell that meets the first selection condition as the target cell, deletes / releases the first primary cell, and selects the target cell as the second primary cell.

[0173] Exemplarily, the terminal device deleting / releasing the first main cell may include: the terminal device deleting the configuration information / parameters corresponding to the first main cell, or the terminal device releasing the connection with the first main cell, or the terminal device stopping data transmission with the first main cell, or the terminal device disconnecting the connection with the first main cell, etc.

[0174] Exemplarily, the terminal device using the target cell as the second primary cell may include: the terminal device uses / applies the parameters of the target cell contained in the CPA information to initiate a random access process to the target cell, and after successfully accessing the target cell, determines the target cell as a new primary cell, and the terminal device can subsequently transmit data with the target cell.

[0175] Further optionally, after the terminal device successfully accesses the second primary cell, the terminal device sends indication information to the network device corresponding to the second primary cell to indicate that RLF has occurred in the first primary cell. The indication information may include at least one of the following: identification information of the first primary cell, indication information that RLF has occurred in the first primary cell, signal quality of the first primary cell, signal quality of at least one candidate primary and secondary cell, etc.; after receiving the indication information, the network device corresponding to the second primary cell may send a third message to the first primary network device. The third message may be used to notify the first primary network device that RLF has occurred in the first primary cell. Optionally, the third message may include indication information that RLF has occurred in the first primary cell, or the third message may include at least one of the above indication information. After receiving the third message, the first primary network device disconnects from the terminal device, no longer provides network services to the terminal device, and no longer transmits service data with the terminal device.

[0176] In this way, before determining the target primary and secondary cells, when RLF occurs in the first primary cell, the terminal device selects a cell that meets the first selection condition from at least one candidate primary and secondary cell as the target cell, and adds it as the target primary and secondary cell or as a new primary cell. Since the context information of the terminal device has been interacted and the service data of the terminal device has been forwarded between the source PCell (i.e., the first primary cell) and at least one candidate PSCell in the preparation stage for adding the candidate PSCell, the terminal device can quickly access the network device corresponding to the target cell to transmit service data, reduce the service interruption time between the terminal device and the network device, and ensure the service transmission between the terminal device and the network device.

[0177] Step 5034b: The terminal device selects a cell that meets the S criterion among at least one candidate primary and secondary cells as a target cell, and the terminal device performs an RRC re-establishment process on the target cell.

[0178] Among them, the process in step 5034b where the terminal device takes a cell that meets the S criterion among at least one candidate primary and secondary cell as the target cell can refer to the process in the above step 5031a where the terminal device takes a cell that meets the S criterion among at least one candidate primary and secondary cell as the target cell, and the process in step 5034b where the terminal device performs the RRC re-establishment process on the target cell can refer to step 5032a where the terminal device takes the target cell as the RRC re-establishment cell and performs the RRC re-establishment process on the target cell, which will not be repeated.

[0179] The process of the terminal device performing the RRC re-establishment process refers to the prior art and will not be described in detail. The cell for the terminal device to re-establish can be any cell that meets the S criterion or the cell selection criterion, such as the first primary cell or other cells, etc., which is not limited in this embodiment.

[0180] Further optionally, after the terminal device establishes an RRC connection with the target cell, the terminal device may also send indication information to the network device corresponding to the target cell to indicate that RLF occurs in the first primary cell. Specifically, the process may refer to the process in which the terminal device sends indication information to the network device corresponding to the target cell in step 5032a above, and will not be repeated here.

[0181] In this way, before determining the target primary and secondary cells, when RLF occurs in the first primary cell and there is no cell that meets the first selection condition in at least one candidate primary and secondary cell, the terminal device selects a cell that meets the S criterion from at least one candidate primary and secondary cell as the target cell for RRC re-establishment. Since the context information of the terminal device has been exchanged and the service data of the terminal device has been forwarded between the source PCell (i.e., the first primary cell) and each candidate primary and secondary cell in at least one candidate PSCell during the preparation stage for adding the candidate PSCell, the terminal device can quickly complete the re-establishment process with the network device corresponding to the target cell without the need to perform the process of obtaining the terminal context information during the re-establishment process.

[0182] Step 5031c: During the validity period of the timer, the terminal device determines whether there is a cell that meets the conditions for adding primary and secondary cells in at least one candidate primary and secondary cell. If there is a cell that meets the conditions for adding primary and secondary cells, step 5032c is executed and the process ends. If no cell that meets the conditions for adding primary and secondary cells is determined during the validity period of the timer or the timer times out, step 5033c is executed and the process ends.

[0183] Among them, a timer can be used to limit the effective duration of the action of the terminal device to determine whether there is a cell that meets the conditions for adding the primary and secondary cells in at least one candidate primary and secondary cell based on the CPA information. The relevant parameters of the timer, such as: the validity period of the timer can be set as needed, and the relevant parameters of the timer can be configured to the terminal device by the first main network device before the RLF occurs in the first main cell (for example, the RRC reconfiguration message containing CPA information sent by the first main network device to the terminal device contains the relevant parameters of the timer), or it can be pre-defined by the protocol without restriction. Among them, the process of the terminal device determining whether there is a cell that meets the conditions for adding the primary and secondary cells in at least one candidate primary and secondary cell can refer to the above and will not be repeated.

[0184] For example, taking the validity period of the timer as 10s as an example. In a possible implementation, the terminal device starts the timer when receiving the CPA information configured by the first main network device. When RLF occurs in the first main cell, if the timer has not timed out, the terminal device can continue to determine whether there is a cell that meets the conditions for adding the main and auxiliary cells in at least one candidate main and auxiliary cell. If a cell that meets the conditions for adding the main and auxiliary cells is determined within 10s, step 5032c is executed. If a cell that meets the conditions for adding the main and auxiliary cells is not found within 10s, or the timer times out / ends when RLF occurs in the first main cell, step 5033c is executed. Another possible implementation method is that when RLF occurs in the first primary cell, the terminal device starts the timer and triggers the timer to start working. Within the validity period of the timer, the terminal device determines whether there is a cell that meets the conditions for adding primary and secondary cells in at least one candidate primary and secondary cell. If a cell that meets the conditions for adding primary and secondary cells is determined within 10 seconds, step 5032c is executed. If a cell that meets the conditions for adding primary and secondary cells is not found within 10 seconds, or the timer times out / ends working, step 5033c is executed.

[0185] Step 5032c: the terminal device takes the cell that meets the primary and secondary cell adding conditions as the target cell, and adds the target cell as the target primary and secondary cell; or deletes / releases the first primary cell, and takes the target cell as the second primary cell.

[0186] Among them, step 5032c can refer to step 5032b and step 5033b, and will not be repeated here.

[0187] Further optionally, in the case where the target cell is added as a target primary and secondary cell, after the terminal device successfully accesses the target cell / target primary and secondary cell, the terminal device sends an indication message to the network device corresponding to the target primary and secondary cell to indicate that RLF has occurred in the first primary cell. The relevant description of the indication message can refer to step 5032b and will not be repeated here. Furthermore, after the network device corresponding to the target primary and secondary cell receives the indication message, it can send a second message to the first primary network device. After the first primary network device receives the second message, the first primary network device disconnects from the terminal device, no longer provides network services to the terminal device, no longer transmits business data with the terminal device, and configures the new primary cell to which the terminal device needs to switch. Specifically, the relevant description of the second message, the process of the network device corresponding to the target primary and secondary cell sending the second message, and the processing process after the first primary network device receives the second message can refer to step 5032b and will not be repeated here.

[0188] Further optionally, after the terminal device uses the target cell as the second primary cell and successfully accesses the second primary cell, the network device corresponding to the second primary cell of the terminal device sends indication information for indicating that RLF occurs in the first primary cell. The relevant description of the indication information can refer to step 5033b and will not be repeated here. Furthermore, after receiving the indication information, the network device corresponding to the second primary cell can send a third message to the first primary network device. After the first primary network device receives the third message, the first primary network device disconnects from the terminal device, no longer provides network services to the terminal device, and no longer transmits business data with the terminal device. Specifically, the relevant description of the third message, the process of the network device corresponding to the second primary cell sending the third message, and the processing process after the first primary network device receives the third message can refer to step 5033b and will not be repeated here.

[0189] Step 5033c: The terminal device selects a cell satisfying the second selection condition among at least one candidate primary and secondary cells as a target cell, deletes / releases the first primary cell, and selects the target cell as a second primary cell, or performs an RRC re-establishment process on the target cell.

[0190] Among them, the process of the terminal device deleting / releasing the first main cell and using the target cell as the second main cell can refer to the corresponding description in the previous text, and the process of the terminal device performing the RRC re-establishment process on the target cell can refer to the corresponding description in the previous text, which will not be repeated here.

[0191] Among them, the second selection condition may include the S criterion or the signal quality is greater than the second threshold. Each candidate primary and secondary cell in at least one candidate primary and secondary cell may correspond to a second selection condition, and the second selection conditions corresponding to different candidate primary and secondary cells may be the same or different. The second threshold can be set as needed, and the second threshold can be the same or different from the first threshold, such as the second threshold can be a threshold value lower than the first threshold. The second threshold may be the same or different from the threshold value in the primary and secondary cell adding condition information of the candidate primary and secondary cell. The second threshold may be agreed upon by the protocol, or sent by the first main network device to the terminal device, and is not limited to this. The signal quality described in this embodiment may include one or more of RSRP, RSRQ and SINR.

[0192] Exemplarily, if the second selection condition includes the S criterion, the terminal device determining whether there is a cell satisfying the second selection condition in at least one candidate primary and secondary cell may include: the terminal device determining whether the signal quality of one or some of the at least one candidate primary and secondary cell satisfies the S criterion; if the signal quality of the candidate primary and secondary cell satisfies the S criterion, the primary and secondary cell may be determined as a cell satisfying the second selection condition; otherwise, it may be determined that the primary and secondary cell does not satisfy the second selection condition.

[0193] If the second selection condition includes that the signal quality is greater than the second threshold, the terminal device may determine whether there is a cell that meets the second selection condition in at least one candidate primary and secondary cell, which may include: determining whether the signal quality of one or some of the at least one candidate primary and secondary cells is higher than the second threshold; if the signal quality of a certain candidate primary and secondary cell is higher than the second threshold, the candidate primary and secondary cell may be determined as a cell that meets the second selection condition; otherwise, it may be determined that the candidate primary and secondary cell does not meet the second selection condition.

[0194] It should be noted that, in the present application, the cell that meets the second selection condition in the candidate primary and secondary cells may be one or more. The terminal device taking the cell that meets the second selection condition as the target cell may include: if there is one cell that meets the second selection condition, then the cell that meets the second selection condition is taken as the target cell; if there are multiple cells that meet the second selection condition, then any cell is selected from the multiple cells that meet the second selection condition as the target cell, or, the candidate primary and secondary cells that meet any one or more of the following conditions among the multiple candidate primary and secondary cells that meet the second selection condition are taken as the target cell: the highest priority, the best (or highest) signal quality, the smallest or largest corresponding cell index, the smallest or largest corresponding configuration identification information (such as CPA-ConfigId or other identification forms); or, the first cell that meets the second selection condition, etc.

[0195] Further optionally, when starting to execute step 5033c, if the second selection condition is that the signal quality is greater than the second threshold, and the second threshold is different from the corresponding threshold value in the primary and secondary cell adding condition information of the candidate primary and secondary cells, the terminal device can stop / no longer determine whether at least one candidate primary and secondary cell meets the primary and secondary cell adding condition to reduce the power consumption of the terminal device. Further optionally, the terminal device can delete / release the CPA information. Optionally, when starting to execute step 5033c, if the second selection condition is that the signal quality is greater than the second threshold, when the terminal device executes step 5033c, the terminal device can determine whether at least one candidate primary and secondary cell meets the S criterion without restriction.

[0196] Further optionally, after the terminal device performs the RRC re-establishment process on the target cell, the terminal device sends indication information to the network device corresponding to the target cell to indicate that RLF occurs in the first main cell. The relevant description of the indication information can refer to step 5032a and will not be repeated here. Furthermore, after receiving the indication information, the network device corresponding to the target cell can send a first message to the first main network device. After the first main network device receives the first message, the first main network device disconnects from the terminal device, no longer provides network services to the terminal device, and no longer transmits business data with the terminal device. Specifically, the relevant description of the first message, the process of the network device corresponding to the target cell sending the first message, and the processing process after the first main network device receives the first message can refer to step 5032a and will not be repeated here.

[0197] In this way, before determining the target primary and secondary cells, when RLF occurs in the first primary cell, the terminal device selects a cell that meets the primary and secondary cell adding conditions from the candidate primary and secondary cells as the target cell within the validity period to add (such as adding the target cell as the target primary and secondary cell) or using the target cell as a new primary cell, or, after the timer expires, selects a target cell that meets the second selection condition for RRC re-establishment or as a new primary cell. Since the context information of the terminal device has been exchanged and the service data of the terminal device has been forwarded between the source PCell (i.e., the first primary cell) and at least one candidate PSCell in the candidate PSCell addition preparation stage, the terminal device can quickly access the network device corresponding to the target cell to transmit service data, reduce the service interruption time between the terminal device and the network device, and ensure the service transmission between the terminal device and the network device.

[0198] Figure 5 The method shown describes the communication method provided by the present application in the scenario where RLF occurs in the first primary cell before the terminal device determines the target primary and secondary cells. Figure 3 The communication system shown in Figure 6Taking the method shown as an example, a communication method in a scenario where RLF occurs in the first primary cell after the terminal device determines the target primary and secondary cell but before successfully accessing the target primary and secondary cell is described:

[0199] Figure 6 A flow chart of a communication method provided in an embodiment of the present application, such as Figure 6 As shown, the method includes:

[0200] Step 601: The terminal device receives CPA information from the first main network device.

[0201] Among them, step 601 can refer to step 501 and will not be repeated here.

[0202] Step 602: After the terminal device determines a first primary and secondary cell that meets the primary and secondary cell adding conditions from at least one candidate primary and secondary cell according to CPA information, before accessing the first primary and secondary cell, the terminal device detects that RLF occurs in the first primary cell.

[0203] Among them, the first primary and secondary cell may be a cell that meets the primary and secondary cell adding conditions in at least one candidate primary and secondary cell. There may be one or more cells that meet the primary and secondary cell adding conditions in at least one candidate primary and secondary cell. Specifically, if there are multiple cells that meet the primary and secondary cell adding conditions in at least one candidate primary and secondary cell, any one of the multiple cells that meet the primary and secondary cell adding conditions in at least one candidate primary and secondary cell may be determined as the first primary and secondary cell. Alternatively, the first primary and secondary cell may be a cell that meets any one or more of the following conditions in the multiple cells that meet the primary and secondary cell adding conditions in at least one candidate primary and secondary cell: the highest priority, the best (or highest) signal quality, the smallest or largest corresponding cell index, the smallest or largest corresponding configuration identification information (such as CPA-ConfigId or other identification forms); or, the first cell that meets the primary and secondary cell adding conditions, etc.

[0204] Specifically, the process of the terminal device determining the first primary and secondary cell that meets the primary and secondary cell adding conditions from at least one candidate primary and secondary cell according to the CPA information can refer to the above, and the process of the terminal device detecting that the RLF occurs in the first primary cell can refer to step 502, which will not be repeated.

[0205] Among them, the first primary and secondary cell can be the target primary and secondary cell to be added; or the first primary and secondary cell or a cell that meets the S criterion in at least one candidate primary and secondary cell can be an RRC reconstruction cell, and the terminal device can perform the RRC re-establishment process on the first primary and secondary cell or a cell that meets the S criterion in at least one candidate primary and secondary cell; or the first primary and secondary cell can be used as the new primary cell, such as the terminal device can delete / release the first primary cell, and use the first primary and secondary cell as the new primary cell (such as recorded as the second primary cell), etc.

[0206] Furthermore, Figure 6 The method shown may further include: step 603 or step 604 or step 605. Specifically, which step of step 603, step 604 and step 605 the terminal device executes may be pre-configured or specified by the protocol, or the network device may instruct the terminal device which step to execute, without limitation.

[0207] Step 603: The terminal device adds the first primary and secondary cells as target primary and secondary cells.

[0208] For example, the terminal device can continue to access the first primary and secondary cell. Specifically, step 603 refers to the process of adding the target cell as the target primary and secondary cell in step 5032b, which will not be described in detail.

[0209] Further optionally, after the terminal device successfully accesses the first primary and secondary cell, the terminal device sends an indication message indicating that the first primary cell has an RLF to the network device corresponding to the first primary and secondary cell. The relevant description of the indication message can refer to the description in step 5032b and will not be repeated here. Furthermore, after the network device corresponding to the first primary and secondary cell receives the indication message, it can send a second message to the first primary network device. After the first primary network device receives the second message, the first primary network device disconnects from the terminal device, no longer provides network services to the terminal device, no longer transmits business data with the terminal device, and configures a new primary cell to be switched to for the terminal device. Specifically, the relevant description of the second message, the process of the network device corresponding to the first primary and secondary cell sending the second message, and the processing process after the first primary network device receives the second message can refer to the network device corresponding to the target cell (or target primary and secondary cell) sending the second message and the processing process after the first main network device receives the second message in step 5032b, and will not be repeated here.

[0210] Step 604: The terminal device determines the target cell and performs the RRC re-establishment process on the target cell.

[0211] Exemplarily, the terminal device determining the target cell may include: the terminal device taking the first primary and secondary cell as the target cell; or, the terminal device stops accessing the first primary and secondary cell and takes a cell that meets the S criterion among at least one candidate primary and secondary cell as the target cell.

[0212] If the target cell is the first primary and secondary cell, the terminal device continues to access the first primary and secondary cell and performs an RRC re-establishment process with the first primary and secondary cell;

[0213] If the target cell is a cell that satisfies the S criterion in at least one candidate primary and secondary cell, the terminal device stops accessing the first primary and secondary cell (such as stopping the random access process with the first primary and secondary cell) and performs an RRC re-establishment process with the target cell. The process in which the terminal device uses a cell that satisfies the S criterion in at least one candidate primary and secondary cell as a target cell can refer to step 5031a, and the process in which the terminal device performs an RRC re-establishment process on the target cell can refer to step 5032a above, which will not be repeated.

[0214] Further optionally, after the terminal device performs the RRC re-establishment process on the target cell, the terminal device sends indication information to the network device corresponding to the target cell to indicate that RLF occurs in the first main cell. The relevant description of the indication information can refer to step 5032a and will not be repeated here. Furthermore, after receiving the indication information, the network device corresponding to the target cell can send a first message to the first main network device. After the first main network device receives the first message, the first main network device disconnects from the terminal device, no longer provides network services to the terminal device, and no longer transmits business data with the terminal device. Specifically, the relevant description of the first message, the process of the network device corresponding to the target cell sending the first message, and the processing process after the first main network device receives the first message can refer to step 5032a and will not be repeated here.

[0215] Step 605: The terminal device deletes / releases the first primary cell, and uses the first primary and secondary cells as the second primary cell.

[0216] For example, the terminal device can continue to access the first primary and secondary cell, and after successfully accessing the first primary and secondary cell, use the first primary and secondary cell as the second primary cell. Specifically, the terminal device can delete / release the first primary cell before successfully accessing the first primary and secondary cell, or after successfully accessing the first primary and secondary cell, or when the terminal device successfully accesses the first primary and secondary cell.

[0217] Specifically, the process of the terminal device deleting / releasing the first primary cell and using the first primary auxiliary cell as the second primary cell can refer to the process of the terminal device deleting / releasing the first primary cell and using the target cell as the second primary cell in step 5033b, which will not be repeated here.

[0218] Further optionally, after the terminal device uses the first primary and secondary cell as the second primary cell and successfully accesses the second primary cell, the network device corresponding to the second primary cell of the terminal device sends indication information for indicating that RLF occurs in the first primary cell. The relevant description of the indication information can refer to step 5033b and will not be repeated here. Furthermore, after receiving the indication information, the network device corresponding to the second primary cell can send a third message to the first primary network device. After the first primary network device receives the third message, the first primary network device disconnects from the terminal device, no longer provides network services to the terminal device, and no longer transmits business data with the terminal device. Specifically, the relevant description of the third message, the process of the network device corresponding to the second primary cell sending the third message, and the processing process after the first primary network device receives the third message can refer to step 5033b and will not be repeated here.

[0219] based on Figure 6 The method shown can be that after determining the target primary and secondary cell (i.e., the first primary and secondary cell) but before accessing the target primary and secondary cell, in the scenario where RLF occurs in the first primary cell, the terminal device will use the determined first primary and secondary cell as the target primary and secondary cell to be added and continue to access it, or use the first primary and secondary cell or at least one candidate primary and secondary cell that meets the S criterion as the RRC reconstruction cell, perform the RRC re-establishment process on the first primary and secondary cell, or use the first primary and secondary cell as the new primary cell. Since the context information of the terminal device has been interacted and the service data of the terminal device has been forwarded between the source PCell (i.e., the first primary cell) and at least one candidate PSCell in the preparation stage for adding the candidate PSCell, the terminal device can quickly access the network device corresponding to the target cell to transmit service data, reduce the service interruption time between the terminal device and the network device, and ensure the service transmission between the terminal device and the network device.

[0220] Figure 5 The method shown is a communication method provided by the present application in the scenario where RLF occurs in the first primary cell before the terminal device determines the target primary and secondary cells. Figure 6 The method shown is for determining the target primary and secondary cells but not accessing the target primary and secondary cells, and the first primary cell has RLF in the scenario described below. Figure 3 The communication system shown in Figure 7 Taking the method shown as an example, a communication method in a scenario where RLF occurs in the first primary cell after the terminal device determines the target primary and secondary cells and accesses the target primary and secondary cells is described:

[0221] Figure 7 A flow chart of a communication method provided in an embodiment of the present application, such as Figure 7 As shown, the method includes:

[0222] Step 701: The terminal device receives CPA information from the first main network device.

[0223] Among them, step 701 can refer to step 501 and will not be repeated here.

[0224] Step 702: The terminal device determines a target primary and secondary cell that meets the primary and secondary cell adding condition from at least one candidate primary and secondary cell according to the CPA information: the first primary and secondary cell, and successfully accesses the first primary and secondary cell.

[0225] Among them, step 702 can refer to the existing technology and will not be repeated here.

[0226] Step 703: The terminal device detects that RLF occurs in the first primary cell, and the terminal device executes step 704 or step 705. Specifically, which step of step 704 or step 705 the terminal device executes may be pre-configured or specified by the protocol, or the network device may instruct the terminal device which step to execute, without limitation.

[0227] The process in which the terminal device detects that RLF occurs in the first primary cell may refer to step 502 and will not be described in detail.

[0228] Step 704: The terminal device deletes / releases the first primary cell, and determines the first primary secondary cell as the second primary cell.

[0229] Among them, the process of the terminal device deleting / releasing the first main cell and using the first main auxiliary cell as the second main cell can refer to the process of the terminal device deleting / releasing the first main cell and using the target cell as the second main cell in step 5033b, and will not be repeated here.

[0230] Further optionally, after the terminal device uses the first primary and secondary cell as the second primary cell and successfully accesses the second primary cell, the network device corresponding to the second primary cell of the terminal device sends indication information for indicating that RLF occurs in the first primary cell. The relevant description of the indication information can refer to step 5033b and will not be repeated here. Furthermore, after receiving the indication information, the network device corresponding to the second primary cell can send a third message to the first primary network device. After the first primary network device receives the third message, the first primary network device disconnects from the terminal device, no longer provides network services to the terminal device, and no longer transmits business data with the terminal device. Specifically, the relevant description of the third message, the process of the network device corresponding to the second primary cell sending the third message, and the processing process after the first primary network device receives the third message can refer to step 5033b and will not be repeated here.

[0231] Step 705: The terminal device receives configuration information configured by the first primary network device through the network device corresponding to the first primary and secondary cells, and the configuration information is used to reconfigure the primary cell.

[0232] Among them, step 705 can refer to the process in which the terminal device obtains the configuration information for reconfiguring the primary cell provided by the first primary network device through the network device corresponding to the target primary and secondary cells in step 5032b, such as: after the terminal device successfully accesses the first primary and secondary cells, the terminal device sends the indication information for indicating that the first primary cell has RLF to the network device corresponding to the first primary and secondary cells. After the network device corresponding to the first primary and secondary cells receives the indication information, it can send a second message to the first primary network device. After the first primary network device receives the second message, the first primary network device disconnects from the terminal device, no longer provides network services for the terminal device, and no longer transmits business data with the terminal device. Optionally, after receiving the second message, the first primary network device reconfigures a new primary cell and sends configuration information to the network device corresponding to the first primary and secondary cells, and the configuration information can be used to reconfigure the primary cell; after receiving the configuration information, the network device corresponding to the first primary and secondary cells sends the configuration information to the terminal device; after receiving the configuration information, the terminal device attempts to change the primary cell from the first primary cell to the new primary cell indicated in the configuration information according to the configuration information.

[0233] Among them, the relevant description of the indication information and the second message, the process of the first main network device configuring a new primary cell, the network device corresponding to the first primary auxiliary cell (i.e., the target primary auxiliary cell) sending the second message to the first main network device, and the processing process after the first main network device receives the second message, and the process of the network device corresponding to the first primary auxiliary cell (i.e., the target primary auxiliary cell) sending the configuration information corresponding to the new primary cell to the terminal device can be referred to as described in step 5032b and will not be repeated here.

[0234] based on Figure 7 According to the method shown, after successfully accessing the target primary and secondary cells, in the scenario where RLF occurs in the first primary cell, the terminal device can obtain a new primary cell reconfigured by the first primary network device from the first primary and secondary cells, or use the first primary and secondary cells as the new primary cells. Since the context information of the terminal device has been interacted and the service data of the terminal device has been forwarded between the source PCell (i.e., the first primary cell) and at least one candidate PSCell in the preparation stage for adding candidate PSCells, the terminal device can quickly access the network device corresponding to the target cell to transmit service data, reduce the service interruption time between the terminal device and the network device, and ensure the service transmission between the terminal device and the network device.

[0235] The above mainly introduces the scheme provided by the embodiment of the present application from the perspective of interaction between each node. It is understandable that each node, such as a network device, a terminal device, includes a hardware structure and / or software module corresponding to each function in order to realize the above functions. It should be easily appreciated by those skilled in the art that the method of the embodiment of the present application can be implemented in the form of hardware, software, or a combination of hardware and computer software in conjunction with the algorithm steps of each example described in the embodiment disclosed herein. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0236] The embodiment of the present application can divide the functional modules of the network device and the terminal device according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0237] Figure 8 The structure diagram of a communication device 80 is shown. The communication device 80 may be a terminal device, a chip in a terminal device, a system on a chip, or other devices capable of implementing the functions of the terminal device in the above method. The communication device 80 may be used to perform the functions of the terminal device involved in the above method embodiment. As an implementable manner, Figure 8 The communication device 80 shown includes: a receiving unit 801, a processing unit 802;

[0238] In one possible design, the receiving unit 801 is configured to receive CPA information indicating parameters of at least one candidate primary and secondary cell and primary and secondary cell adding condition information of each candidate primary and secondary cell from the first primary network device. For example, the receiving unit 801 can support the communication device 80 to perform step 501.

[0239] The processing unit 802 is configured to detect that the first primary cell has RLF before determining the cell that meets the primary and secondary cell adding conditions according to the CPA information, determine the target cell from at least one candidate primary and secondary cell, add the target cell as the target primary and secondary cell, or perform a radio resource control RRC re-establishment process on the target cell, or delete the first primary cell and use the target cell as the second primary cell. For example, the processing unit 802 can support the communication device 80 to execute step 502, step 5031a, step 5032a, step 5031b, step 5032b, step 5033b, step 5034b, step 5031c, step 5032c, and step 5033c.

[0240] Specifically, the above Figure 5 All relevant contents of each step involved in the illustrated method embodiment can be referred to the functional description of the corresponding functional module, and will not be repeated here. The communication device 80 is used to execute Figure 5 The method shown has the function of the terminal device in the communication method shown, so it can achieve the same effect as the above-mentioned communication method.

[0241] In one possible design, the processing unit 802 is used to determine a first primary and secondary cell that meets the primary and secondary cell adding condition from at least one candidate primary and secondary cell according to the CPA information indicating the parameters of at least one candidate primary and secondary cell received from the first primary network device and the primary and secondary cell adding condition information of each candidate primary and secondary cell, and if the RLF of the first primary cell is detected before the terminal device successfully accesses the first primary and secondary cell, the first primary and secondary cell is added as the target primary and secondary cell, or the target cell is determined and the RRC re-establishment process is performed on the target cell, or the first primary cell is deleted and the first primary and secondary cell is used as the second primary cell. For example, the processing unit 802 can support the communication device 80 to perform steps 602, 603, 604, and 605.

[0242] Specifically, the above Figure 6 All relevant contents of each step involved in the illustrated method embodiment can be referred to the functional description of the corresponding functional module, and will not be repeated here. The communication device 80 is used to execute Figure 6 The method shown has the function of the terminal device in the communication method shown, so it can achieve the same effect as the above-mentioned communication method.

[0243] In one possible design, the processing unit 802 is configured to determine, from at least one candidate primary and secondary cell, a first primary and secondary cell that meets the primary and secondary cell adding condition according to the CPA information indicating the parameters of at least one candidate primary and secondary cell and the primary and secondary cell adding condition information of each candidate primary and secondary cell received from the first primary network device, if after successfully accessing the first primary and secondary cell, it is detected that the first primary cell has RLF, delete the first primary cell, and determine the first primary and secondary cell as the second primary cell; or, receive the configuration information configured by the first primary network device through the network device corresponding to the first primary and secondary cell, and the configuration information is used to reconfigure the primary cell. For example, the processing unit 802 can support the communication device 80 to execute steps 702, 703, 704, and 705.

[0244] Specifically, the above Figure 7 All relevant contents of each step involved in the illustrated method embodiment can be referred to the functional description of the corresponding functional module, and will not be repeated here. The communication device 80 is used to execute Figure 7 The method shown has the function of the terminal device in the communication method shown, so it can achieve the same effect as the above-mentioned communication method.

[0245] As another possible way to achieve this, Figure 8 The communication device 80 shown includes: a processing module and a communication module. The processing module is used to control and manage the actions of the communication device 80. For example, the processing module can integrate the function of the processing unit 802, and can be used to support the communication device 80 to execute step 502, step 5031a, step 5032a, step 5031b, step 5032b, step 5033b, step 5034b, step 5031c, step 5032c and step 5033c, step 602, step 603, step 604, step 605, step 702, step 703, step 704, step 705 and other processes of the technology described in this document. The communication module can integrate the function of the receiving unit 801, and can be used to support the communication device 80 to execute step 501 and communicate with other network entities, such as with Figure 3 The communication device 80 may also include a storage module for storing instructions and / or data. When the instructions are executed by the processing module, the processing module implements the method executed by the above terminal device.

[0246] The processing module may be a processor, a controller, a module or a circuit. It may implement or execute various exemplary logic blocks described in conjunction with the disclosure of the present application. The communication module may be a transceiver circuit, a pin, an interface circuit, a bus interface, or a communication interface. The storage module may be a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the communication device 80 involved in the embodiment of the present application may be Figure 4 The communication device shown.

[0247] In the embodiments of the present application, the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, and may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the method disclosed in the embodiments of the present application may be directly embodied as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0248] In the embodiment of the present application, the memory may be a non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), etc., or a volatile memory (volatile memory), such as a random-access memory (RAM). The memory is any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory in the embodiment of the present application may also be a circuit or any other device that can implement a storage function, for storing instructions and / or data.

[0249] Fig. 9 A structural diagram of a communication system provided in an embodiment of the present application, such as Fig. 9 As shown, the communication system may include: a terminal device 90 and a plurality of network devices 91. The terminal device 90 may be a terminal device supporting DC. The network device 91 may include a main network device connected to the terminal device 90 and a secondary network device to be added.

[0250] Among them, the terminal device 90 can have the functions of the above-mentioned communication device 80, which will not be repeated.

[0251] Specifically, the specific implementation process of the terminal device 90 can refer to the above Figure 5-Figure 7 The execution process of the terminal device in the method embodiment will not be repeated here.

[0252] The embodiment of the present application also provides a computer-readable storage medium. All or part of the processes in the above method embodiments can be completed by a computer program to instruct the relevant hardware, and the program can be stored in the above computer-readable storage medium. When the program is executed, it can include the processes of the above method embodiments. The computer-readable storage medium can be a terminal device of any of the above embodiments, such as: an internal storage unit including a data sending end and / or a data receiving end, such as a hard disk or memory of a terminal device. The above computer-readable storage medium can also be an external storage device of the above terminal device, such as a plug-in hard disk equipped on the above terminal device, a smart memory card (smart media card, SMC), a secure digital (secure digital, SD) card, a flash card (flash card), etc. Further, the above computer-readable storage medium can also include both an internal storage unit of the above terminal device and an external storage device. The above computer-readable storage medium is used to store the above computer program and other programs and data required by the above terminal device. The above computer-readable storage medium can also be used to temporarily store data that has been output or is to be output.

[0253] The present application also provides a computer instruction. All or part of the process in the above method embodiment can be completed by computer instructions to instruct related hardware (such as computers, processors, network devices, and terminals, etc.). The program can be stored in the above computer-readable storage medium.

[0254] It should be noted that the terms "first" and "second" in the specification, claims and drawings of the present application are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0255] It should be understood that in the present application, "at least one (item)" means one or more, "more than one" means two or more, "at least two (items)" means two or three and more than three, and "and / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0256] It should be understood that in the embodiments of the present application, "B corresponding to A" means that B is associated with A. For example, B can be determined based on A. It should also be understood that determining B based on A does not mean determining B only based on A, but B can also be determined based on A and / or other information. In addition, the "connection" that appears in the embodiments of the present application refers to various connection methods such as direct connection or indirect connection to achieve communication between devices, and the embodiments of the present application do not impose any limitation on this.

[0257] Unless otherwise specified, the "transmission" (transmit / transmission) appearing in the embodiments of the present application refers to bidirectional transmission, including sending and / or receiving actions. Specifically, the "transmission" in the embodiments of the present application includes the sending of data, the receiving of data, or the sending of data and the receiving of data. In other words, the data transmission here includes uplink and / or downlink data transmission. Data may include channels and / or signals, uplink data transmission is uplink channel and / or uplink signal transmission, and downlink data transmission is downlink channel and / or downlink signal transmission. The "network" and "system" appearing in the embodiments of the present application express the same concept, and the communication system is the communication network.

[0258] Through the description of the above implementation methods, technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0259] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0260] The units described as separate components may or may not be physically separated, and the components shown as units may be one physical unit or multiple physical units, that is, they may be located in one place or distributed in multiple different places. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0261] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0262] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium, including several instructions to enable a device, such as a single-chip microcomputer, a chip, etc., or a processor (processor) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard drives, ROM, RAM, magnetic disks or optical disks.

[0263] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A communication method, It is characterized in that include: Receiving conditional primary and secondary cell addition CPA information from the first primary network device, where the CPA information indicates parameters of at least one candidate primary and secondary cell and primary and secondary cell addition condition information of each candidate primary and secondary cell; Before determining the cell that meets the primary and secondary cell adding condition according to the CPA information, detecting that a radio link failure RLF occurs in the first primary cell, the first primary cell is managed by the first primary network device; Determine a target cell from the at least one candidate primary and secondary cell; The target cell is added as a target primary and secondary cell, or a radio resource control (RRC) re-establishment process is performed on the target cell, or the first primary cell is deleted and the target cell is used as a second primary cell.

2. The method according to claim 1, It is characterized in that The determining of the target cell includes: A cell that meets the S criterion among the at least one candidate primary and secondary cell is used as the target cell.

3. The method according to claim 1, It is characterized in that The determining of the target cell includes: Determining whether there is a cell that meets the first selection condition among the at least one candidate primary and secondary cells; If there is a cell satisfying the first selection condition among the at least one candidate primary and secondary cell, the cell satisfying the first selection condition is used as the target cell; The first selection condition is a condition for adding a primary or secondary cell, or a signal quality greater than a first threshold.

4. The method according to claim 3, It is characterized in that The method further comprises: If there is no cell satisfying the first selection condition in the at least one candidate primary and secondary cell, a cell satisfying the S criterion in the at least one candidate primary and secondary cell is used as the target cell.

5. The method according to claim 1, It is characterized in that The determining of the target cell includes: Within the validity period of the timer, determining whether there is a cell in the at least one candidate primary and secondary cell that meets the primary and secondary cell adding condition; If there is a cell satisfying the primary and secondary cell adding condition among the at least one candidate primary and secondary cell, the cell satisfying the primary and secondary cell adding condition is used as the target cell.

6. The method according to claim 5, It is characterized in that The method further comprises: If a cell that meets the conditions for adding the primary and secondary cells is not determined within the validity period of the timer, or the timer times out, a cell that meets the second selection condition among the at least one candidate primary and secondary cells is used as the target cell, and the second selection condition is the S criterion or the signal quality is greater than a second threshold.

7. The method according to any one of claims 1 to 6, It is characterized in that The method further comprises: Send indication information to a network device corresponding to the target cell, where the indication information is used to indicate that RLF occurs in the first primary cell.

8. The method according to claim 7, It is characterized in that When the target cell is added as a target primary and secondary cell, the method further includes: Receive configuration information from a network device corresponding to the target cell, where the configuration information is configured by the first master network device, and the configuration information is used to reconfigure the master cell.

9. A communication method, It is characterized in that The method comprises: Determine, according to the conditional primary and secondary cell addition CPA information received from the first primary network device, a first primary and secondary cell that meets the primary and secondary cell addition condition from at least one candidate primary and secondary cell, wherein the CPA information indicates parameters of the at least one candidate primary and secondary cell and primary and secondary cell addition condition information of each candidate primary and secondary cell; Before successfully accessing the first primary and secondary cells, a radio link failure RLF is detected in the first primary cell, and the first primary cell is managed by the first primary network device; The first primary and secondary cell is added as a target primary and secondary cell, or a target cell is determined, and a radio resource control (RRC) re-establishment process is performed on the target cell, or the first primary cell is deleted and the first primary and secondary cell is used as a second primary cell.

10. The method according to claim 9, It is characterized in that The determining of the target cell includes: Continue to access the first primary and secondary cell and use the first primary and secondary cell as the target cell; or, Stop accessing the first primary and secondary cell, and use a cell that meets the S criterion among the at least one candidate primary and secondary cell as the target cell.

11. The method according to claim 9 or 10, It is characterized in that The method further comprises: Send indication information, where the indication information is used to indicate that RLF occurs in the first primary cell.

12. The method according to claim 11, It is characterized in that When the first primary and secondary cell is added as a target primary and secondary cell, the sending indication information includes: Sending the indication information to a network device corresponding to the first primary and secondary cells; The method further includes: receiving configuration information from a network device corresponding to the first primary and secondary cells, the configuration information being configured by the first primary network device, and the configuration information being used to reconfigure the primary cell.

13. A communication device, It is characterized in that It includes a receiving unit and a processing unit. The receiving unit is configured to receive conditional primary and secondary cell addition CPA information from the first primary network device, where the CPA information indicates parameters of at least one candidate primary and secondary cell and primary and secondary cell addition condition information of each candidate primary and secondary cell; The processing unit is used to detect that a radio link failure RLF occurs in the first primary cell managed by the first primary network device before determining a cell that meets the conditions for adding a primary or secondary cell according to the CPA information, determine a target cell from the at least one candidate primary or secondary cell, add the target cell as a target primary or secondary cell, or perform a radio resource control RRC re-establishment process on the target cell, or delete the first primary cell and use the target cell as a second primary cell.

14. The communication device according to claim 13, It is characterized in that The processing unit is configured to use a cell that satisfies the S criterion among the at least one candidate primary and secondary cell as the target cell.

15. The communication device according to claim 13, It is characterized in that The processing unit is used for: Determining whether there is a cell that meets the first selection condition among the at least one candidate primary and secondary cells; If there is a cell satisfying the first selection condition among the at least one candidate primary and secondary cell, the cell satisfying the first selection condition is used as the target cell; The first selection condition is a condition for adding a primary or secondary cell, or a signal quality greater than a first threshold.

16. The communication device according to claim 15, It is characterized in that The processing unit is configured to use a cell that satisfies an S criterion among the at least one candidate primary and secondary cell as the target cell if there is no cell that satisfies the first selection condition among the at least one candidate primary and secondary cell.

17. The communication device according to claim 13, It is characterized in that The processing unit is used for: Within the validity period of the timer, determining whether there is a cell in the at least one candidate primary and secondary cell that meets the primary and secondary cell adding condition; If there is a cell satisfying the primary and secondary cell adding condition among the at least one candidate primary and secondary cell, the cell satisfying the primary and secondary cell adding condition is used as the target cell.

18. The communication device according to claim 17, It is characterized in that The processing unit is used to use a cell that meets the second selection condition among the at least one candidate primary and secondary cells as the target cell if a cell that meets the conditions for adding the primary and secondary cells is not determined within the validity period of the timer, or the timer times out, wherein the second selection condition is the S criterion or the signal quality is greater than a second threshold.

19. The communication device according to any one of claims 13 to 18, It is characterized in that The processing unit is used to send indication information to the network device corresponding to the target cell, where the indication information is used to indicate that RLF occurs in the first primary cell.

20. The communication device according to claim 19, It is characterized in that When the target cell is added as a target primary and secondary cell, the receiving unit is further used to receive configuration information from a network device corresponding to the target cell, the configuration information is configured by the first primary network device, and the configuration information is used to reconfigure the primary cell.

21. A communication device, It is characterized in that Including processing unit, The processing unit is configured to determine, according to the conditional primary and secondary cell addition CPA information received from the first primary network device, a first primary and secondary cell that meets the primary and secondary cell addition condition from at least one candidate primary and secondary cell, wherein the CPA information indicates parameters of the at least one candidate primary and secondary cell and primary and secondary cell addition condition information of each candidate primary and secondary cell; The processing unit is also used to detect, before successfully accessing the first primary and secondary cells, that a radio link failure RLF occurs in the first primary cell managed by the first primary network device, and add the first primary and secondary cell as a target primary and secondary cell, or determine a target cell and perform a radio resource control RRC re-establishment process on the target cell, or delete the first primary cell and use the first primary and secondary cell as a second primary cell.

22. The communication device according to claim 21, It is characterized in that The processing unit is further used to continue accessing the first primary and secondary cell and use the first primary and secondary cell as the target cell; or stop accessing the first primary and secondary cell and use a cell that meets the S criterion among the at least one candidate primary and secondary cell as the target cell.

23. The communication device according to claim 21 or 22, It is characterized in that The processing unit is further used to send indication information, where the indication information is used to indicate that RLF occurs in the first primary cell.

24. The communication device according to claim 23, It is characterized in that When the first primary and secondary cell is added as a target primary and secondary cell, the processing unit is further configured to: Sending the indication information to a network device corresponding to the first primary and secondary cells; Configuration information is received from a network device corresponding to the first primary and secondary cells, where the configuration information is configured by the first primary network device and is used to reconfigure the primary cell.

25. A communication system, It is characterized in that The communication system comprises: A first master network device, and a communication apparatus for implementing the communication method as described in any one of claims 1 to 8 or for implementing the communication method as described in any one of claims 9 to 12.

26. A computer-readable storage medium, It is characterized in that The computer-readable storage medium stores computer instructions, and when the computer instructions are executed on a computer, the computer executes the communication method according to any one of claims 1 to 8; or the computer is used to execute the communication method according to any one of claims 9 to 12.

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