Communication method, apparatus and system

Abstract

Provided in the present application are a communication method, apparatus and system. In the method, an access network device not only indicates, in system information of a cell, groups for which the current cell supports timing and a master clock time corresponding to each group, but also indicates at least one neighboring cell of the cell and groups for which each neighboring cell supports timing. When an AF initiates to a network a service request for group timing, a terminal device can determine, on the basis of received system information, whether a cell currently accessed by the terminal device supports timing for a group (e.g., denoted as a target group) to which the terminal device belongs, and when the cell currently accessed by the terminal device does not support timing for the group to which the terminal device belongs, the terminal device can find, from among neighboring cells of the cell, cells (e.g., denoted as candidate cells) that support timing for the target group, such that the terminal device can access one of the candidate cells by means of requesting a handover, performing cell re-selection, etc., thereby facilitating an improvement in the reliability of group timing.

Description

Communication method, device and system

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on February 22, 2024, with application number 202410201754.7 and application name “A Communication Method, Device and System”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and in particular to a communication method, device, and system. Background Art

[0003] With the continuous increase in business demand, the concept of base station timing is proposed. The base station can broadcast timing to the terminal at the cell granularity through system information, such as system information block 9 (SIB9).

[0004] In future industrial scenarios, such as robotic arm collaboration and automated guided vehicle collaboration, clock synchronization will be required for industrial equipment in the same dynamic collaboration group, while industrial equipment in different dynamic collaboration groups will need to be synchronized to the master clock of the dynamic collaboration group. Therefore, base stations will need to perform broadcast group timing to meet different business needs.

[0005] When the base station sends a SIB9 message for broadcast timing, the SIB9 message can carry clock domain information. For example, the SIB9 message can include a clock domain identification field and a master clock time field. The information in these two fields is corresponding. The clock domain identification field can indicate the clock domain, and the master clock time field can indicate the master clock time of the corresponding clock domain. After the terminal receives the SIB9 message sent by the base station, it can select according to the clock domain identification carried in the SIB9 message, and then obtain the master clock time corresponding to the clock domain it needs, thereby completing group timing. However, the length of the system broadcast is limited, and the number of clock domain information that the SIB9 message can carry is limited, or the number of clock domains that the SIB9 message can indicate is limited. It may be impossible to carry the clock domain information of all groups that the base station needs to synchronize in the same SIB9 message. Therefore, the existing technology cannot ensure that the SIB9 message received by the terminal contains the clock domain information it needs, that is, the base station cannot ensure that the group timing requirements of the terminal are met. Summary of the Invention

[0006] The present application provides a communication method, device and system to improve the reliability of group timing.

[0007] In a first aspect, a communication method is provided, which can be applied to a communication device. The communication device can be, for example, a terminal device, or a component configured in the terminal device (such as a chip, a chip system, a processor, etc.), or a logic module or software capable of implementing all or part of the functions of the terminal device. This application is not limited to this.

[0008] Exemplarily, the method includes: receiving first system information, the first system information indicating at least one group for which the first cell supports timing and the master clock time corresponding to each group, as well as at least one adjacent cell of the first cell and the group for which each adjacent cell in the at least one adjacent cell supports timing, the first cell is the cell accessed by the terminal device, the group includes one or more terminal devices, and the master clock time is used to provide timing for each terminal device in the corresponding group; determining, based on the first system information, that at least one group for which the first cell supports timing does not include a target group, and that the at least one adjacent cell includes one or more candidate cells, the candidate cell is a cell that supports timing for the target group, and the target group is the group to which the terminal device belongs; sending a switching request, the switching request carrying an identifier of each candidate cell in the one or more candidate cells.

[0009] Based on the above scheme, the access network device can not only indicate the groups that the cell supports timing and the master clock time corresponding to each group in the system information (such as the first system information), but also indicate at least one adjacent cell of the cell and the groups that each adjacent cell supports timing. In this way, the terminal device can determine whether the currently accessed cell (such as the first cell) supports timing for the group to which the terminal device belongs (for example, recorded as the target group) based on the received first system information, and if it does not support it, it can select one or more candidate cells from the adjacent cells of the cell that can provide timing for the target group, further initiate a switching request, and request that the terminal device be switched to the candidate cell, which is conducive to improving the reliability of group timing.

[0010] In combination with the first aspect, in some possible implementations of the first aspect, the method further includes: receiving first indication information, the first indication information indicating the frequency of each candidate cell in the one or more candidate cells; performing measurement based on the frequency of each candidate cell in the one or more candidate cells to obtain a measurement report, the measurement report indicating the measurement result of the signal quality of each candidate cell; and sending the measurement report.

[0011] Since there is a corresponding relationship between frequency points and cells, the terminal device can indicate the frequency point of each candidate cell in one or more candidate cells based on the first indication information, measure the signal quality of each candidate cell, and thus obtain a measurement report, so that the access network device can obtain the communication quality of each cell according to the measurement report, and then determine the target cell for the terminal device.

[0012] In combination with the first aspect, in some possible implementations of the first aspect, the method also includes: receiving first indication information, the first indication information indicating the frequency of the at least one adjacent cell; performing measurement based on the frequency of the at least one adjacent cell to obtain a measurement report, the measurement report indicating the measurement result of the signal quality of each adjacent cell; and sending the measurement report.

[0013] The terminal device can measure the signal quality of at least one adjacent cell according to the frequency of at least one adjacent cell indicated by the first indication information, thereby obtaining a measurement report. The measurement result indicated in the measurement report can be used as a parameter to measure the communication quality of each cell.

[0014] In combination with the first aspect, in some possible implementations of the first aspect, the method also includes: receiving second indication information, the second indication information instructing the terminal device to switch to a second cell, the second cell being the cell with the best signal quality among the one or more candidate cells; and switching to the second cell based on the second indication information.

[0015] Based on the measurement results indicated in the measurement report, the access network device selects the cell with the best signal quality from one or more candidate cells as the second cell, and sends the second cell along with the second indication information to the terminal device. Based on the second indication information, the terminal device can determine that the access network device has instructed it to switch from the currently connected first cell to the second cell. This ensures that the terminal can obtain the required group time while also ensuring communication quality.

[0016] In a second aspect, a communication method is provided, which can be applied to a communication device. The communication device can be, for example, a terminal device, or a component configured in the terminal device (such as a chip, a chip system, a processor, etc.), or a logic module or software capable of implementing all or part of the functions of the terminal device. This application is not limited to this.

[0017] Exemplarily, the method includes: receiving first system information, the first system information indicating at least one group of the first cell supporting timing and the master clock time corresponding to each group, as well as at least one adjacent cell of the first cell and the group of each adjacent cell in the at least one adjacent cell supporting timing, the first cell is the cell accessed by the terminal device, the group includes one or more terminal devices, and the master clock time is used to provide timing for each terminal device in the corresponding group; based on the first system information, determining the priority ranking of the first cell and the at least one adjacent cell, the priority of the cell that supports timing for the target group is higher than the priority of the cell that does not support timing for the target group, and the target group is the group to which the terminal device belongs; and performing cell reselection based on the priority ranking.

[0018] Based on the above solution, the access network device can indicate not only the groups that the cell supports timing and the master clock time corresponding to each group in the system information (such as the first system information), but also at least one adjacent cell of the cell and the groups that each adjacent cell supports timing. In this way, when the application function network element (AF) initiates a service request for group timing to the network, the terminal device can prioritize the first cell and at least one adjacent cell based on the received first system information, and then initiate cell reselection based on the priority ranking, so that the terminal device switches to the adjacent cell that can support timing for the group to which the terminal device belongs, which is conducive to improving the reliability of group timing.

[0019] In combination with the second aspect, in some possible implementations of the second aspect, the cell reselection based on the priority sorting includes: switching to the second cell when the priority of the second cell in the at least one adjacent cell is higher than the priority of the first cell.

[0020] When the first cell does not support timing for the target group, the terminal device can switch from the currently accessed first cell to the second cell that supports timing for the target group based on priority sorting, so that the terminal device can access the cell that can meet the group timing service requirements, thereby improving the reliability of group timing.

[0021] In combination with the second aspect, in some possible implementations of the second aspect, before switching to the second cell, the method further includes: measuring the signal quality of the second cell; and determining that the signal quality of the second cell is higher than a preset threshold.

[0022] By measuring the signal quality of the second cell, it is determined that the signal quality of the second cell is higher than a preset threshold, which is beneficial to improving the reliability of communication of the terminal device in the second cell.

[0023] In a third aspect, a communication method is provided, which can be applied to a communication device. The communication device can be, for example, an access network device, or a component configured in the access network device (such as a chip, a chip system, a processor, etc.), or a logic module or software capable of implementing all or part of the functions of the access network device. This application is not limited to this.

[0024] Exemplarily, the method includes: receiving a first message from a core network network element, the first message being used to indicate a first group and a terminal device that provides a master clock time for the first group, the master clock time being used to provide timing for each terminal device in the corresponding group; sending a first system information, the first system information indicating the group timing information of the service cell of the access network device, and at least one adjacent cell of the service cell and a group that each adjacent cell supports timing, the group timing information of the service cell indicating at least one group that the service cell supports timing and the master clock time corresponding to each group, the first group being a group that a third cell supports timing, and the third cell being the service cell of the access network device or an adjacent cell of the service cell.

[0025] Based on the above scheme, when there is a need to create a group, the AF can indicate the group requested to be created and its corresponding master clock time through the first message. For the convenience of distinction and explanation, the group created by the AF request is recorded as the first group in this article. The access network device can obtain the master clock time corresponding to the first group based on the received first message, and then allocate the master clock time corresponding to the first group to the cell (for example, the third cell), and update the system information (for example, the first system information) based on the first message. The first system information is further sent down through broadcasting. The first system information can not only indicate the group that the service cell of the core network device supports timing, but also indicate at least one group that supports timing of at least one adjacent cell of the service cell. In this way, the terminal device can determine whether it can obtain the cell that is timing the target group to which it belongs based on the first system information, which is conducive to improving the reliability of group timing, saving transmission overhead, and improving resource utilization.

[0026] In combination with the third aspect, in some possible implementations of the third aspect, the first message is also used to indicate the valid period of the master clock time of the first group, and the master clock time of the first group is effective during the valid period; the method also includes: sending second system information, and the group supported by the third cell supported by the second system information does not include the first group.

[0027] The first message can also carry the validity period of the master clock time of the first group, so that after receiving the first message, the access network device can periodically delete or cancel a group (such as the first group) and its corresponding master clock time, and broadcast the second system information. This second system information can not only indicate the groups that the third cell supports timing, but also indicate at least one group that at least one neighboring cell of the third cell supports timing, where the groups supported by the third cell do not include the first group. In this way, resource overhead can be saved, resource utilization can be improved, and energy consumption can be reduced.

[0028] In combination with the third aspect, in some possible implementations of the third aspect, the method also includes: receiving a second message from the core network network element, the second message being used to indicate deletion of the first group and its corresponding master clock time; sending third system information, the group supported by the third cell as indicated by the third system information not including the first group.

[0029] The access network device can also receive a second message, delete or cancel a group (e.g., the first group) and its corresponding master clock time based on the second message, and broadcast third system information. This second system information can indicate not only the groups supported by the third cell but also at least one group supported by at least one neighboring cell of the third cell, where the groups supported by the third cell do not include the first group. This can save resource overhead, improve resource utilization, and reduce energy consumption.

[0030] In combination with the third aspect, in some possible implementations of the third aspect, the method further includes: receiving a switching request from a terminal device, the switching request carrying an identifier of each candidate cell in the one or more candidate cells, and the switching request being used to request that the terminal device be switched from the first cell to one of the one or more candidate cells; based on the switching request, sending first indication information to the terminal device, the first indication information indicating a frequency to be measured, the frequency to be measured being the frequency of each candidate cell in the one or more candidate cells; receiving a measurement report from the terminal device, the measurement report indicating a measurement result of the signal quality of each candidate cell; and determining a second cell based on the measurement report, the second cell being the cell with the best signal quality among the one or more candidate cells.

[0031] Based on the received handover request, the access network equipment can initiate signal quality measurements of one or more candidate cells. Finally, based on the measurement results indicated in the measurement report, it can handover the terminal device to the candidate cell with the best signal quality. This not only helps improve the reliability of group timing, but also enhances the communication quality of the terminal device in the candidate cells.

[0032] In combination with the third aspect, in some possible implementations of the third aspect, the method further includes: receiving a switching request from the terminal device, the switching request carrying an identifier of each candidate cell in the one or more candidate cells, and the switching request being used to request that the terminal device be switched from the first cell to one of the one or more candidate cells; based on the switching request, sending first indication information to the terminal device, the first indication information indicating a frequency to be measured, the frequency to be measured being the frequency of each adjacent cell in at least one adjacent cell of the first cell; receiving a measurement report from the terminal device, the measurement report indicating a measurement result of the signal quality of each adjacent cell; determining a second cell based on the measurement report and the one or more candidate cells, the second cell being the cell with the best signal quality among the one or more candidate cells.

[0033] Based on the received handover request, the access network device can initiate a signal quality measurement of at least one neighboring cell of the first cell. Finally, based on the measurement results indicated in the measurement report and one or more candidate cells, the device can be handed over to the candidate cell with the best signal quality. This not only helps improve the reliability of group timing, but also enhances the communication quality of the terminal device in the candidate cells.

[0034] In a fourth aspect, a communication method is provided, which can be applied to a communication device. The communication device can be, for example, a first communication unit of an access network device, or a component configured in the first communication unit of the access network device (such as a chip, a chip system, a processor, etc.), or a logic module or software capable of implementing all or part of the functions of the first communication unit of the access network device. This application is not limited to this.

[0035] Exemplarily, the method includes: receiving a first message from a core network network element, the first message indicating a first group and a master clock time corresponding to the first group, the master clock time being used to provide timing for each terminal device in the corresponding group; sending a first configuration update message to at least one second communication unit of the access network device, the first configuration update message indicating the group timing information of the service cell of the second communication unit, the group timing information of the service cell indicating at least one group supported by the service cell and the master clock time corresponding to each group, the first group being a group supported by a third cell for timing, the third cell being the service cell of the access network device or an adjacent cell of the service cell, the at least one second communication unit including: a second communication unit to which the third cell belongs, and a second communication unit to which at least one adjacent cell of the third cell belongs.

[0036] Based on the above scheme, when there is a need to create a group, the AF can indicate the group (for example, the first group) requested to be created and its corresponding master clock time through a first message. The first communication unit (for example, CU) of the access network device obtains the master clock time corresponding to the first group based on the received first message, and then allocates the master clock time corresponding to the first group to the cell (for example, the third cell), and updates the first configuration update message based on the first message. In the first configuration update message, the first communication unit can not only indicate the groups that the cell supports timing and the master clock time corresponding to each group, but also indicate at least one adjacent cell of the cell and the groups that each adjacent cell supports timing. The first communication unit can send the first configuration update message to at least one second communication unit (for example, DU). The first configuration update can indicate which groups the serving cell of the second communication unit supports timing, and which groups the adjacent cells of the serving cell support timing, thereby helping the second communication unit to update the system information based on the first configuration update message. In this way, it is beneficial to improve the reliability of group timing, save resource overhead, and improve resource utilization.

[0037] In combination with the fourth aspect, in some possible implementations of the fourth aspect, the first message is also used to indicate the valid period of the master clock time of the first group, and the master clock time of the first group is effective during the valid period; the method also includes: sending a second configuration update message to the at least one second communication unit, and the group of the third cell supporting timing indicated by the second configuration update message does not include the first group.

[0038] The first message can also carry the validity period of the master clock time of the first group, so that after receiving the first message, the first communication unit of the access network device can periodically delete or cancel a group (such as the first group) and its corresponding master clock time, and send a second configuration update message to at least one second communication unit to notify the third cell and its neighboring cells of changes in the group timing information of the third cell, where the groups supported by the third cell do not include the first group. This can save resource overhead, improve resource utilization, and reduce energy consumption.

[0039] In combination with the fourth aspect, in some possible implementations of the fourth aspect, the method also includes: receiving a second message from the core network network element, the second message being used to indicate deletion of the first group and its corresponding master clock time; sending a third configuration update message to the at least one second communication unit, the group of timing supported by the third cell indicated by the third configuration update message not including the first group.

[0040] The first communication unit (e.g., CU) of the access network device can also receive the second message and, based on the group deletion indication carried in the second message, delete or cancel a group (e.g., the first group) and its corresponding master clock time. The device then broadcasts a third configuration update message to the at least one second communication unit (e.g., DU) to notify the third cell and its neighboring cells of changes in the group timing information of the third cell. The groups supported by the third cell for timing do not include the first group. This saves resource overhead, improves resource utilization, and reduces energy consumption.

[0041] In combination with the fourth aspect, in some possible implementations of the fourth aspect, the method further includes: receiving a switching request from a terminal device, the switching request carrying an identifier of each candidate cell in the one or more candidate cells, and the switching request being used to request that the terminal device be switched from the first cell to one of the one or more candidate cells; based on the switching request, sending first indication information to the terminal device, the first indication information indicating a frequency to be measured, the frequency to be measured being the frequency of each candidate cell in the one or more candidate cells; receiving a measurement report from the terminal device, the measurement report indicating a measurement result of the signal quality of each candidate cell; and determining a second cell based on the measurement report, the second cell being the cell with the best signal quality among the one or more candidate cells.

[0042] The first communication unit (e.g., CU) of the access network device can initiate a signal quality measurement of one or more candidate cells based on the received handover request. Finally, based on the measurement results indicated in the measurement report, the terminal device is handed over to the candidate cell with the best signal quality. This not only helps improve the reliability of group timing, but also enhances the communication quality of the terminal device in the candidate cells.

[0043] In combination with the fourth aspect, in some possible implementations of the fourth aspect, the method further includes: receiving a switching request from a terminal device, the switching request carrying an identifier of each candidate cell in the one or more candidate cells, and the switching request being used to request that the terminal device be switched from the first cell to one of the one or more candidate cells; based on the switching request, sending first indication information to the terminal device, the first indication information indicating a frequency to be measured, the frequency to be measured being the frequency of each adjacent cell in at least one adjacent cell of the first cell; receiving a measurement report from the terminal device, the measurement report indicating a measurement result of the signal quality of each adjacent cell; determining a second cell based on the measurement report and the one or more candidate cells, the second cell being the cell with the best signal quality among the one or more candidate cells.

[0044] Based on the received handover request, the first communication unit (e.g., CU) of the access network device can initiate a signal quality measurement of at least one neighboring cell of the first cell. Finally, based on the measurement results indicated in the measurement report and one or more candidate cells, the terminal device is handed over to the candidate cell with the best signal quality. This not only helps improve the reliability of group timing, but also enhances the communication quality of the terminal device in the candidate cells.

[0045] In a fifth aspect, a communication method is provided, which can be applied to a communication device. The communication device can be, for example, a first communication unit of an access network device, or a component configured in the first communication unit of the access network device (such as a chip, a chip system, a processor, etc.), or a logic module or software capable of implementing all or part of the functions of the first communication unit of the access network device. This application is not limited to this.

[0046] Exemplarily, the method includes: receiving a third message from a core network element, the third message indicating a terminal device requesting timing and a target group, the target group being the group to which the terminal device belongs, and the group including one or more terminal devices; based on the third message, at least one group supported by the first cell for timing, and each of at least one adjacent cell of the first cell supporting timing for a group, determining that at least one group supported by the first cell for timing does not include the target group, and that the at least one adjacent cell includes one or more candidate cells, the candidate cell being a cell supporting timing for the target group, and the first cell being the cell accessed by the terminal device; determining to switch the terminal device to a second cell among the one or more candidate cells.

[0047] Based on the above scheme, when the AF initiates a service request for group timing to the network, the terminal device requesting timing and the target group to which it belongs can be sent to the first communication unit of the access network device through a third message. The first communication unit can determine whether the first cell currently accessed by the terminal device supports timing for the target group based on the mapping relationship between the pre-stored cell and the group that the cell supports timing, and if it does not support, it can find a second cell that supports timing for the target group from the adjacent cells of the cell, and then initiate a cell handover for the terminal device and switch the terminal device to the second cell. This is conducive to improving the reliability of group timing.

[0048] In combination with the fifth aspect, in some possible implementations of the fifth aspect, the second cell is a cell with the best signal quality among the one or more candidate cells.

[0049] Switching the terminal device to the candidate cell with the best signal quality not only helps improve the reliability of group timing, but also improves the communication quality of the terminal device in the candidate cell.

[0050] In combination with the fifth aspect, in some possible implementations of the fifth aspect, before determining to switch the terminal device to the second cell among the one or more candidate cells, the method also includes: sending first indication information to the terminal device, the first indication information indicating the frequency of each candidate cell in the one or more candidate cells; receiving a measurement report from the terminal device, the measurement report indicating the measurement results of the signal quality of each candidate cell; and determining the second cell based on the measurement report.

[0051] The terminal device can indicate the frequency of each of one or more candidate cells based on the first indication information, measure the signal quality of each candidate cell, and thereby obtain a measurement report. Based on the measurement results indicated in the measurement report, the first communication unit can determine the candidate cell with the best signal quality as the second cell, and then hand over the terminal device from the first cell to the second cell. This not only helps improve the reliability of group timing, but also improves the communication quality of the terminal device in the candidate cells.

[0052] In combination with the fifth aspect, in some possible implementations of the fifth aspect, the third message is further used to indicate a valid period of the master clock time of the target group, and the master clock time of the target group is effective within the valid period.

[0053] The third message can also carry the valid period of the master clock time of the target group, so that after receiving the third message, the first communication unit can regularly delete or cancel a certain group (such as the target group) and its corresponding master clock time. In other words, the first communication unit can update the correspondence between the second cell and at least one group that the second cell supports timing based on the third message. In the updated mapping relationship, at least one group that the second cell supports timing does not include the target group. In this way, transmission overhead can be reduced and energy consumption can be reduced.

[0054] In combination with the fifth aspect, in some possible implementations of the fifth aspect, the method also includes: sending a fourth configuration update message to at least one second communication unit of the access network device, the fourth configuration update message indicating the group timing information of the second cell, and at least one adjacent cell of the second cell and the group that each adjacent cell in the at least one adjacent cell supports timing, the group timing information of the second cell indicates at least one group that the second cell supports timing and the master clock time corresponding to each group, and the group that the second cell supports timing indicated by the fourth configuration update message does not include the target group.

[0055] When the target group's master clock time is no longer in the valid period, meaning the target group and its corresponding master clock time supported by the second cell are deleted, the first communication unit sends a fourth configuration update message to at least one second communication unit, informing the second cell that the target group is no longer supported by the second cell. This not only improves the reliability of group timing but also reduces transmission overhead.

[0056] In combination with the fifth aspect, in some possible implementations of the fifth aspect, after determining to switch the terminal device to the second cell among the one or more candidate cells, the method also includes: receiving a fourth message from the core network network element, the fourth message being used to indicate deletion of the target group and its corresponding master clock time; and deleting the correspondence between the second cell and the target group.

[0057] Optionally, another implementation method for deleting a group and its corresponding master clock time is to use a fourth message, which may carry a group deletion instruction. The first communication unit may delete the target group and its corresponding master clock time based on the fourth message. In other words, the first communication unit may update the mapping between the second cell and at least one group supported by the second cell for timing based on the fourth message. In the updated mapping, the at least one group supported by the second cell for timing does not include the target group. This reduces transmission overhead and energy consumption.

[0058] In combination with the fifth aspect, in some possible implementations of the fifth aspect, the method further includes: sending a fifth configuration update message to the at least one second communication unit, and the group of the second cell supporting timing indicated by the fifth configuration update message does not include the target group.

[0059] After the first communication unit receives the fourth message, indicating that the target group supported by the second cell for timing and its corresponding master clock time have been deleted, the first communication unit sends a fifth configuration update message to at least one second communication unit, informing the second cell that the target group is no longer supported for timing. This not only improves the reliability of group timing but also reduces transmission overhead.

[0060] In a sixth aspect, a communication method is provided, which can be applied to a communication device. The communication device can be, for example, a second communication unit of an access network device, or a component configured in the second communication unit of the access network device (such as a chip, a chip system, a processor, etc.), or a logic module or software capable of implementing all or part of the functions of the second communication unit of the access network device. This application is not limited to this.

[0061] Exemplarily, the method includes: receiving a configuration update message from a first communication unit of the access network device, the configuration update message indicating group timing information of a third cell, the group timing information of the third cell indicating at least one group that the third cell supports timing and a master clock time corresponding to each group, each group including one or more terminal devices, and the master clock time being used to provide timing for each terminal device in the corresponding group; based on the configuration update message, sending system information, the system information indicating the group timing information of the service cell of the second communication unit, and at least one adjacent cell of the service cell and a group that each adjacent cell supports timing, the third cell being the service cell of the second communication unit or an adjacent cell of the service cell.

[0062] Based on the above solution, the second communication unit of the access network device can update the first system information based on the group timing information of the third cell indicated by the received first configuration update message, and carry the group timing information of the third cell and at least one group of at least one neighboring cell of the third cell that supports timing in the first system information. The second communication unit broadcasts the first system information, and the terminal device that receives the first system information can determine whether it can obtain the cell that provides timing for the group to which it belongs based on the first system information. This is conducive to improving the reliability of group timing, saving resource overhead, and improving resource utilization.

[0063] In a seventh aspect, a communication method is provided, which can be applied to a communication device. The communication device can be, for example, a core network element, or a component configured in the core network element (such as a chip, a chip system, a processor, etc.), or a logic module or software capable of implementing all or part of the functions of the access network element. This application is not limited to this.

[0064] Exemplarily, the method includes: generating a first message, the first message being used to indicate a first group, a terminal device providing a master clock time for the first group, and a valid period of the master clock time of the first group, the master clock time being used to provide time for each terminal device in the corresponding group, the master clock time of the first group being effective within the valid period; and sending the first message.

[0065] Based on the above solution, after receiving the first message, the access network device can periodically delete or cancel a group (e.g., the first group) and its corresponding master clock time based on the validity period of the first group's master clock time indicated in the first message. This can save resource overhead, improve resource utilization, and reduce energy consumption.

[0066] In an eighth aspect, a communication method is provided, which can be applied to a communication device. The communication device can be, for example, a core network element, or a component configured in the core network element (such as a chip, a chip system, a processor, etc.), or a logic module or software capable of implementing all or part of the functions of the access network element. This application is not limited to this.

[0067] Exemplarily, the method includes: generating a first message, the first message being used to indicate a first group and a terminal device that provides a master clock time for the first group, the master clock time being used to provide time for each terminal device in the corresponding group; sending the first message; generating a second message, the second message being used to indicate deletion of the first group and its corresponding master clock time; and sending the second message.

[0068] Based on the above solution, after receiving the second message, the access network device can periodically delete or cancel a group (e.g., the first group) and its corresponding master clock time based on the second message. This can save resource overhead, improve resource utilization, and reduce energy consumption.

[0069] In a ninth aspect, the present application provides a communication device comprising modules or units for implementing the methods in the first to second aspects and any possible implementation of the first to second aspects. Each module or unit can implement the corresponding function by executing a computer program.

[0070] In a tenth aspect, the present application provides a communication device, comprising a processor, wherein the processor is configured to execute the communication method described in the first to second aspects and any possible implementation of the first to second aspects.

[0071] The apparatus may further include a memory for storing instructions and data. The memory is coupled to the processor, and when the processor executes the instructions stored in the memory, the methods described in the above aspects may be implemented. The apparatus may further include a communication interface for communicating between the apparatus and other devices. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0072] Illustratively, the apparatus in the ninth aspect or the tenth aspect is a terminal device, or a component in a terminal device, such as a chip, a chip system, a processor, etc.

[0073] In the eleventh aspect, the present application provides a chip system comprising at least one processor for supporting the implementation of the functions involved in the above-mentioned first to second aspects and any possible implementation methods of the first to second aspects, for example, receiving or processing the information involved in the above-mentioned method.

[0074] In one possible design, the chip system further includes a memory, which is used to store program instructions and data, and the memory is located inside or outside the processor.

[0075] The chip system can be composed of chips, or can include chips and other discrete devices.

[0076] In one possible design, the chip system further includes a power supply circuit, which is used to supply power to the chip system.

[0077] In a twelfth aspect, the present application provides a communication device, comprising modules or units for implementing the method in the third aspect and any possible implementation of the third aspect. Each module or unit can implement the corresponding function by executing a computer program.

[0078] In a thirteenth aspect, the present application provides a communication device comprising a processor, wherein the processor is used to execute the communication method described in the third aspect and any possible implementation manner of the third aspect.

[0079] The apparatus may further include a memory for storing instructions and data. The memory is coupled to the processor, and when the processor executes the instructions stored in the memory, the methods described in the above aspects may be implemented. The apparatus may further include a communication interface for communicating between the apparatus and other devices. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0080] Exemplarily, the apparatus in the twelfth aspect or the thirteenth aspect is an access network device, or a component in the access network device, such as a chip, a chip system, a processor, etc.

[0081] In the fourteenth aspect, the present application provides a chip system comprising at least one processor for supporting the implementation of the functions involved in the above-mentioned third aspect and any possible implementation of the third aspect, for example, receiving or processing the information involved in the above-mentioned method.

[0082] In one possible design, the chip system further includes a memory, which is used to store program instructions and data, and the memory is located inside or outside the processor.

[0083] The chip system can be composed of chips, or can include chips and other discrete devices.

[0084] In one possible design, the chip system further includes a power supply circuit, which is used to supply power to the chip system.

[0085] In a fifteenth aspect, the present application provides a communication device, comprising modules or units for implementing the method in the fourth or fifth aspect and any possible implementation of the fourth or fifth aspect. Each module or unit can implement the corresponding function by executing a computer program.

[0086] In the sixteenth aspect, the present application provides a communication device, comprising a processor, wherein the processor is used to execute the communication method described in the fourth or fifth aspect and any possible implementation of the fourth or fifth aspect.

[0087] The apparatus may further include a memory for storing instructions and data. The memory is coupled to the processor, and when the processor executes the instructions stored in the memory, the methods described in the above aspects may be implemented. The apparatus may further include a communication interface for communicating between the apparatus and other devices. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0088] Exemplarily, the apparatus in the fifteenth aspect or the sixteenth aspect is the first communication unit of the access network device, or a component in the first communication unit of the access network device, such as a chip, a chip system, a processor, etc.

[0089] In the seventeenth aspect, the present application provides a chip system comprising at least one processor for supporting the implementation of the functions involved in the above-mentioned fourth or fifth aspect and any possible implementation of the fourth or fifth aspect, for example, receiving or processing the information involved in the above-mentioned method.

[0090] In one possible design, the chip system further includes a memory, which is used to store program instructions and data, and the memory is located inside or outside the processor.

[0091] The chip system can be composed of chips, or can include chips and other discrete devices.

[0092] In one possible design, the chip system further includes a power supply circuit, which is used to supply power to the chip system.

[0093] In an eighteenth aspect, the present application provides a communication device, comprising modules or units for implementing the method in the sixth aspect and any possible implementation of the sixth aspect. Each module or unit can implement the corresponding function by executing a computer program.

[0094] In the nineteenth aspect, the present application provides a communication device, comprising a processor, wherein the processor is used to execute the communication method described in the sixth aspect and any possible implementation of the sixth aspect.

[0095] The apparatus may further include a memory for storing instructions and data. The memory is coupled to the processor, and when the processor executes the instructions stored in the memory, the methods described in the above aspects may be implemented. The apparatus may further include a communication interface for communicating between the apparatus and other devices. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0096] Exemplarily, the apparatus in aspect 18 or aspect 19 is a second communication unit of an access network device, or a component in the second communication unit of an access network device, such as a chip, a chip system, a processor, etc.

[0097] In the twentieth aspect, the present application provides a chip system comprising at least one processor for supporting the implementation of the functions involved in the above-mentioned sixth aspect and any possible implementation of the sixth aspect, for example, receiving or processing the information involved in the above-mentioned method.

[0098] In one possible design, the chip system further includes a memory, which is used to store program instructions and data, and the memory is located inside or outside the processor.

[0099] The chip system can be composed of chips, or can include chips and other discrete devices.

[0100] In one possible design, the chip system further includes a power supply circuit, which is used to supply power to the chip system.

[0101] In a twenty-first aspect, the present application provides a communication device comprising modules or units for implementing the method in the seventh or eighth aspect and any possible implementation of the seventh or eighth aspect. Each module or unit can implement the corresponding function by executing a computer program.

[0102] In aspect 22, the present application provides a communication device comprising a processor, wherein the processor is used to execute the communication method described in aspect 7 or aspect 8 and any possible implementation of aspect 7 or aspect 8.

[0103] The apparatus may further include a memory for storing instructions and data. The memory is coupled to the processor, and when the processor executes the instructions stored in the memory, the methods described in the above aspects may be implemented. The apparatus may further include a communication interface for communicating between the apparatus and other devices. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0104] Exemplarily, the device in aspect 21 or aspect 22 is a core network element, or a component in a core network element, such as a chip, a chip system, a processor, etc.

[0105] In aspect 23, the present application provides a chip system comprising at least one processor for supporting the implementation of the functions involved in the above-mentioned seventh or eighth aspect and any possible implementation of the seventh or eighth aspect, for example, receiving or processing the information involved in the above-mentioned method.

[0106] In one possible design, the chip system further includes a memory, which is used to store program instructions and data, and the memory is located inside or outside the processor.

[0107] The chip system can be composed of chips, or can include chips and other discrete devices.

[0108] In one possible design, the chip system further includes a power supply circuit, which is used to supply power to the chip system.

[0109] In the twenty-fourth aspect, the present application provides a computer-readable storage medium comprising a computer program, which, when executed on a computer, enables the computer to implement the method in aspects one to eight and any possible implementation of aspects one to eight.

[0110] In aspect 25, the present application provides a computer program product, comprising: a computer program (also referred to as code, or instructions), which, when run, enables a computer to execute the method in aspects 1 to 8 and any possible implementation of aspects 1 to 8.

[0111] In aspect 26, an embodiment of the present application provides a communication system, including the aforementioned terminal device, access network device, core network network element, and a first communication unit and a second communication unit of the access network device.

[0112] Aspects 9 to 26 of this application correspond to the technical solutions of aspects 1 to 8 of this application. The beneficial effects achieved by each aspect and the corresponding feasible implementation methods are similar and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0113] FIG1 is a schematic diagram of a network system architecture applicable to the method provided in an embodiment of the present application;

[0114] FIG2 is a schematic diagram of a system architecture provided in an embodiment of the present application;

[0115] FIG3 is a schematic flow chart of the interaction between a terminal device, an access network device, and a core network element according to an embodiment of the present application;

[0116] FIG4 is a possible schematic flowchart of the AF sending a request message to the core network element and the core network element sending the first message provided in an embodiment of the present application;

[0117] FIG5 is another schematic flowchart of a possible embodiment of the present application, in which the AF sends a request message to the core network element and the core network element sends the first message;

[0118] FIG6 is a possible schematic flowchart of the AF sending a request message to the core network element and the core network element sending the second message provided in an embodiment of the present application;

[0119] FIG7 is a schematic flow chart of a communication method provided in an embodiment of the present application;

[0120] FIG8 is another schematic flow chart of the communication method provided in an embodiment of the present application;

[0121] FIG9 is another schematic flow chart of the communication method provided in an embodiment of the present application;

[0122] 10 and 11 are schematic diagrams of a communication device provided in an embodiment of the present application;

[0123] FIG12 is a schematic structural diagram of a terminal device provided in an embodiment of the present application;

[0124] FIG13 is a schematic structural diagram of an access network device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0125] The technical solution provided in this application will be described below in conjunction with the accompanying drawings.

[0126] The method provided in this application can be applied to various communication systems, such as: long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD) system, fifth generation (5G) mobile communication system or new radio access technology (NR). Among them, the 5G mobile communication system may include non-standalone (NSA) and / or standalone (SA) networking.

[0127] The technical solution provided in this application can also be applied to machine type communication (MTC), long term evolution-machine (LTE-M), device-to-device (D2D) network, machine-to-machine (M2M) network, Internet of Things (IoT) network or other networks. Among them, the IoT network can include, for example, the Internet of Vehicles. Among them, the communication mode in the Internet of Vehicles system is collectively referred to as vehicle to other devices (vehicle to X, V2X, X can represent anything) system, for example, the V2X can include: vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) communication or vehicle to network (V2N) communication, etc.

[0128] The technical solution provided in this application can also be applied to future communication systems, such as the sixth generation (6G) mobile communication system, etc. This application does not limit this.

[0129] Figure 1 is a schematic diagram of a network system architecture applicable to the method provided in an embodiment of the present application. As shown in the figure, the network system architecture mainly includes: terminal equipment, radio access network (RAN) equipment and core network equipment.

[0130] Terminal equipment may also be called user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device.

[0131] A terminal device is a device with wireless transceiver functions. The terminal device can communicate with one or more core network (CN) devices (or core devices) via an access network device (or access device) in a wireless access network. The terminal device can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; it can also be deployed on the water (such as a ship, etc.); it can also be deployed in the air (such as an airplane, a balloon, and a satellite, etc.). In an embodiment of the present application, the terminal device may be a terminal device in an Internet of Things (IoT) system. For example, the terminal device may be an A-IoT device. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network of human-machine interconnection and object-to-object interconnection. The connection can be through broadband technology or narrowband (NB) technology. IoT technology can achieve massive connections, deep coverage, and terminal power saving through, for example, narrowband technology.

[0132] In the embodiments of the present application, the device for realizing the function of the terminal device can be a terminal device, or a device capable of supporting the terminal device to realize the function, such as a chip system, which can be installed in the terminal device or used in combination with the terminal device. In the embodiments of the present application, the chip system can be composed of a chip, or it can include a chip and other discrete devices. In the embodiments of the present application, only the terminal device is used as an example for description, and the embodiments of the present application are not limited to the solutions of the embodiments of the present application.

[0133] The terminal device in this application can be a hardware device, a software function running on dedicated hardware, a software function running on general-purpose hardware, or a virtualized device, for example, implemented by general-purpose hardware and instantiated virtualization functions, or by dedicated hardware and instantiated virtualization functions. The general-purpose hardware can be a server, such as a cloud server.

[0134] In the embodiments of the present application, a radio access network device can be any device with wireless transceiver capabilities. A radio access network device can provide wireless communication services and connect terminal devices to a wireless network. A radio access network can also be referred to as an access network device or a network device. A radio access network device can also be referred to as a RAN node or an access network device.

[0135] In one possible scenario, a RAN node may be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next-generation NodeB (gNB), a next-generation base station in a sixth-generation (6G) mobile communication system, or a base station in a future mobile communication system. A RAN node may be a macro base station, a micro base station, an indoor station, a relay node, a donor node, or a radio controller in a cloud radio access network (CRAN) scenario. Optionally, a RAN node may also be a server.

[0136] In another possible scenario, multiple RAN nodes collaborate to assist the terminal in achieving wireless access, and different RAN nodes respectively implement part of the functions of the base station. For example, the RAN node can be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU can be set separately, or they can be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0137] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in an open access network (open RAN, O-RAN or ORAN) system, CU may also be called open CU (O-CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0138] The core network functions of mobile communication networks (such as 5G, 6G, etc.) include: registration and connection management of terminal devices, session management and other functions. The core network network elements mainly include network exposure function (NEF), policy control function (PCF), application function (AF), access and mobility management function (AMF), session management function module (SMF), user plane function (UPF), unified data management (UDM), authentication server function (AUSF), time sensitive communication and time synchronization function (TSCTSF) and data network (DN), etc.

[0139] The NEF can be used to open services and capabilities provided by the 3rd Generation Partnership Project (3GPP) network function (NF) to the AF, while also obtaining external application information from the AF. In other words, the NEF can provide interfaces for third-party applications, such as application programming interfaces (APIs).

[0140] PCF mainly performs policy control on quality of service (QoS) and charging.

[0141] The AF primarily communicates application-side requests to the network and can be considered an application server or an application server proxy. It can provide certain application-layer services to terminal devices. When providing services to terminal devices, the AF has requirements for billing and QoS policies, which it must notify the network of. Furthermore, the AF requires core network devices to provide feedback on application-related information.

[0142] The AMF mainly performs functions such as mobility management and access authentication / authorization. In addition, the AMF network element is also responsible for transmitting user policies between terminal devices and PCF network elements.

[0143] SMF mainly performs session management, allocation and management of Internet Protocol (IP) addresses of user devices, and UPF selection.

[0144] The UPF is primarily used for packet routing and forwarding, policy and QoS processing, and usage reporting. The UPF is a DN-supported interface that performs user-plane data forwarding, session- and flow-level billing and statistics, and bandwidth limiting. User data can be sent to data networks (such as the Internet) through this network element.

[0145] UDM mainly handles access authentication, user identification, authentication / authorization, mobility and mobility management.

[0146] AUSF mainly provides 3GPP and non-3GPP unified access authentication services.

[0147] The main function of TSCTSF is to associate the time synchronization service request of NF consumers with the AF session of PCF; detect the availability of 5GS bridge information of Ethernet and IP type PDU sessions reported by PCF, and realize deterministic forwarding management capabilities within the 5G system.

[0148] DN mainly provides business services to users.

[0149] Network elements communicate with each other through interfaces. For example, the interface between the NEF and AF is the N33 interface. The signaling plane interface between the terminal device and the AMF is the N1 interface. Since the terminal device cannot interact directly with the core network equipment, it must transparently transmit non-access stratum (NAS) information through the access stratum (AS). The signaling plane interface through which the AMF requests the access network (AN) to allocate resources for the protocol data unit (PDU) session is the N2 interface.

[0150] The above description of the various network elements in the core network and the interfaces between them is merely illustrative and does not constitute any limitation on this application. Furthermore, the various network elements shown in the figure can be understood as network elements used to implement different functions in the core network, for example, they can be combined into network slices as needed. These core network elements can be independent devices or integrated into the same device to implement different functions. This application does not limit the specific form of these network elements.

[0151] It can be understood that the network elements used in future communication systems can be the above-mentioned network elements, or can be network elements with other names that have the same or similar functions. This application does not limit this.

[0152] In the embodiments of the present application, access network devices and core network elements may be collectively referred to as network devices. The device used to implement the functions of the network device may be a network device; it may also be a device capable of supporting the network device in implementing the functions, such as a chip system, a hardware circuit, a software module, or a hardware circuit and a software module. The device may be installed in the network device or used in conjunction with the network device. The embodiments of the present application are described using the network device as an example, and do not limit the embodiments of the present application.

[0153] The network device in this application can be a hardware device, a software function running on dedicated hardware, a software function running on general-purpose hardware, or a virtualized device, for example, implemented by general-purpose hardware and instantiated virtualization functions, or by dedicated hardware and instantiated virtualization functions. The general-purpose hardware can be a server, such as a cloud server.

[0154] In addition, Figure 1 exemplarily shows the interfaces between various network elements. For example, the terminal device and the radio access network device communicate via the Uu interface, the radio access network device and the AMF can communicate via the N2 interface, etc., which are not detailed here and are not limited in this application.

[0155] To facilitate understanding of the embodiments of the present application, a brief explanation of the terms involved in the present application is first given.

[0156] 1. Cell: The coverage area of ​​each access network device can be divided into one or more cells, and each cell corresponds to a frequency range, and each cell can operate within the corresponding frequency range. The frequency range can be a frequency point or a frequency band, which is not limited in this application.

[0157] In the embodiment of the present application, different cells may correspond to the same access network device or to different access network devices.

[0158] For example, the DU serving the first cell and the DU serving the second cell may be different DUs. In other words, the first cell and the second cell may be managed by different DUs.

[0159] For another example, the DU serving the first cell and the DU serving the second cell may be the same DU. In other words, the first cell and the second cell may be managed by the same DU.

[0160] Each access network device may serve one or more cells. Cells served by the same access network device may operate in different frequency ranges or in the same frequency range.

[0161] It should be understood that the wireless resources supported by each cell are not limited to the frequency range, but may also include time domain resources, spatial domain resources, etc., which are not listed here one by one.

[0162] 2. Handover: In a wireless communication system, when a terminal device moves from or approaches one cell to another, handover is required to maintain uninterrupted communication of the terminal device.

[0163] In the embodiment of the present application, the handover may be an intra-DU cell handover or an inter-DU cell handover (or intra-CU cell handover), which is not limited in the present application. Intra-DU cell handover may refer to handover between cells served by the same DU, and inter-DU cell handover may refer to handover between cells served by different DUs.

[0164] 3. System information: System information is cell-level information and can be sent by broadcast. System information (SI) may include a master information block (MIB) and multiple system information blocks (SIBs). Each system information contains a series of parameters. For example, in an embodiment of the present application, SIB9 may contain information related to the global positioning system (GPS) time and universal time coordinated (UTC), and the terminal device can obtain UTC, GPS, local time, etc. based on the parameters provided by the system information. The time synchronization parameters indicated in SIB9 are shown in Table 1:

[0165] Table 1

[0166] The leap seconds in Table 1 indicate that since the Earth's rotation time is not exactly 24 hours, when the error between the universal time and the atomic time determined by a precision atomic clock exceeds 0.9 seconds, the universal time will be adjusted to advance or slow down by one second to ensure that the two times are consistent.

[0167] Based on the time synchronization parameters carried in the above SIB9, the terminal device can obtain GPS time, UTC and local time, and can also obtain the reference time of the 5G internal system clock.

[0168] 4. Clock domain: This field can be used to identify the clock source. A clock domain corresponds to a group and can be used to indicate the clock source used by the terminal devices within the group. A clock domain can be identified by its clock domain identifier, the corresponding group's external network identifier, or the internal network group identifier.

[0169] Currently, the system information broadcast by a cell includes time synchronization parameters to indicate the groups that the cell supports timing, thereby meeting the service requirements of group timing. For example, the time synchronization parameters include the clock domain (e.g., "time domain(s)") and the master clock time (e.g., "t_domain(s)"), and their corresponding descriptions are shown in Table 2 below:

[0170] Table 2

[0171] 5. Radio Resource Control (RRC) Connection: Before normal communication, a terminal device can establish an RRC connection with a network device, or in other words, an RRC connection with a cell. When the RRC connection is disconnected, the terminal device may enter the RRC idle state (also referred to as the idle state) or the deactivated state (inactive state), and cannot communicate normally.

[0172] To facilitate understanding of the embodiments of the present application, the following points are first explained:

[0173] First, for ease of understanding and explanation, the following assumptions and definitions are made:

[0174] First cell: the cell where the terminal device resides before switching, or the cell where the terminal device resides before cell reselection.

[0175] Second cell: The cell to which the terminal device is about to switch. The second cell may be a cell adjacent to the first cell. It should be understood that the adjacent cells of the first cell may include but are not limited to the second cell.

[0176] The third cell is a serving cell of the access network device. For example, the third cell includes the first cell and / or the second cell.

[0177] First DU: A DU serving a first cell. The cell of the first DU may include the first cell or other cells except the first cell.

[0178] Second DU: A DU serving a second cell. The second DU's cell may include the second cell or other cells other than the second cell. The first DU and the second DU may be the same DU or different DUs.

[0179] Second, to facilitate a clear description of the technical solutions of the embodiments of this application, in the embodiments of this application, terms such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. For example, the first cell and the second cell are merely used to distinguish between different cells and do not limit their order or quantity. Those skilled in the art will understand that terms such as "first" and "second" do not limit the quantity or execution order, and that terms such as "first" and "second" do not necessarily indicate differences.

[0180] Third, "sending" and "receiving" in the embodiments of the present application indicate the direction of signal transmission. For example, "sending a first message to the access network device" can be understood as the destination end of the information being the access network device, which can include direct sending through the air interface, and also includes indirect sending through the air interface by other units or modules. "Receiving a first message from a core network device" can be understood as the source end of the first message being the core network device, which can include direct receiving from the core network device through the air interface, and also includes indirect receiving from the core network device through the air interface from other units or modules. "Sending" can also be understood as the "output" of the chip interface, and "receiving" can also be understood as the "input" of the chip interface.

[0181] Fourth, in the embodiments of the present application, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, 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 represent: a; b; c; a and b; a and c; b and c; or a and b and c. Among them, a, b, and c can be single or multiple.

[0182] Fifth, in the embodiments of the present application, "when", "if" and "if" all mean that the device will perform corresponding processing under certain objective circumstances, which does not limit the time, nor does it require that the device must perform a judgment action when it is implemented, nor does it mean that there are other limitations.

[0183] Figure 2 is a schematic diagram of the system architecture provided by an embodiment of the present application. The architecture diagram shown in Figure 2 may include: AF, core network equipment, access network equipment, and terminal equipment.

[0184] Figure 2 shows the AF as a device deployed outside the core network, but this should not constitute any limitation to the present application. The AF in the embodiment of the present application can be a device deployed outside the core network, for example, a third-party application (such as an IoT platform in an enterprise network), and the AF can obtain various capabilities provided by the network through the core network network element (such as the NEF in 5G and 6G). The AF in the embodiment of the present application can also be a network element deployed in the core network, such as the AF shown in Figure 1 above, and this application does not limit this.

[0185] For example, the access network device shown in Figure 2 may include a CU and one or more DUs (such as DU 1 and DU 2 shown in the figure). The CU may be connected to the one or more DUs, and each DU may serve one or more cells.

[0186] When the AF requests the network to provide group timing services for terminal devices, the AF can send a request message to the core network device. This request message is used to request group timing. After the core network device processes the received request message, the core network element (such as the AMF in Figure 1) sends an N2 interface message to the access network device. The N2 interface message carries the request for group timing. After receiving the N2 interface message, the access network device generates system information based on the N2 interface message. The access network device can broadcast this system information to provide group timing to the terminal device requesting timing.

[0187] When the AF requests the network to provide group timing to the terminal device, the access network device can carry different group timing information through the SIB9 in the system information to complete the group timing service. However, due to the limited length of the system information, the access network device may not be able to carry all the group timing information requested in the same SIB9. Therefore, it cannot ensure that the SIB9 received by the terminal device contains the group timing information it needs. In other words, the access network device cannot guarantee that the group timing requirements of the terminal device are met, and the reliability of the group timing service is low.

[0188] In view of this, the present application provides a method, in which the access network device indicates in the system information of the cell not only the groups that the cell supports timing and the master clock time corresponding to each group, but also indicates at least one adjacent cell of the cell and the groups that each adjacent cell supports timing. In this way, when the AF initiates a service request for group timing to the network, the terminal device can determine whether the cell currently accessed by the terminal device (such as the first cell) supports timing for the group to which the terminal device belongs (for example, recorded as the target group) based on the received system information, and if it does not support it, it can find a cell that supports timing for the target group from the adjacent cells of the cell (for the convenience of distinction and explanation, recorded as a candidate cell), so that it can access one of the candidate cells (such as the second cell) by requesting switching or cell reselection, which is conducive to improving the reliability of group timing.

[0189] In another implementation, the access network device can determine whether the first cell currently accessed by the terminal device supports timing for the target group based on the mapping relationship between the pre-stored cells and the groups that support timing for the cells, and if it does not support, it can find a second cell that supports timing for the target group from the adjacent cells of the cell, and then initiate a cell switching for the terminal device, switching the terminal device to the second cell, which is beneficial to improving the reliability of group timing.

[0190] The technical solution provided in this application will be described below in conjunction with the accompanying drawings.

[0191] Figures 3 to 9 are schematic flow charts of the communication method provided in the embodiments of the present application. In Figures 3 to 9, the methods provided in the present application are described using the interaction between communication devices as an example, but this should not constitute any limitation on the present application. In addition, each communication device in the figure can also be replaced by a component in each communication device, such as a chip, a chip system, a processor, etc., and can also be replaced by a logic module or software that can implement some or all of its functions. This application does not limit this.

[0192] In addition, in the flowcharts shown in Figures 3 to 9, the method provided in the present application is described by taking the first communication unit as CU and the second communication unit as DU as an example, but this should not constitute any limitation to the present application. The access network device may also have more or fewer communication units, or the access network device may also be deployed in other forms.

[0193] 3 , the communication method 300 shown in FIG3 may include steps 301 to 305. Each step in the method 300 is described in detail below.

[0194] In step 301, a core network element sends a first message to an access network device. Correspondingly, the access network device receives the first message from the core network element.

[0195] When the AF has a timing requirement for a group, it can indicate the group for which timing is requested and its corresponding master clock time through a request message. For the convenience of distinction and description, the group for which the AF requests timing is referred to as the first group in this document.

[0196] In response to the request message, the core network element (such as AMF) can send a first message (i.e., an example of an N2 message) to the access network device through the N2 interface to request timing for the first group.

[0197] The first message may be used to indicate a first group and a terminal device that provides a master clock time for the first group. The terminal device that provides the master clock time for the first group may be used to determine the master clock time corresponding to the first group, and the master clock time is used to provide timing for each terminal device in the corresponding group. For example, the master clock time corresponding to the first group is used to provide timing for each terminal device in the first group.

[0198] The first message can identify the first group by the group identifier of the first group, and can also identify the terminal device that provides the master clock time for the first group by the device identifier. In other words, a possible design for the first message to indicate the first group and the terminal device that provides the master clock time for the first group is that the first message carries the group identifier of the first group and the device identifier of the terminal device that provides the master clock time for the first group. The group identifier is used to identify the group in the communication system, and each group has a unique group identifier. Each group includes one or more terminal devices, and the one or more terminal devices included in each group have the same group identifier.

[0199] Optionally, when AF requests timing for a terminal device, the terminal device joins the first group, and the access network device has previously stored the master clock time of the first group. At this time, the first message is used to indicate the device identification of the terminal device, without indicating the first group to which the terminal device belongs and the terminal device that provides the master clock time for the first group.

[0200] For ease of understanding, FIG4 exemplarily shows a possible process of the AF sending a request message to the core network element and the core network element sending the first message.

[0201] In step 401, the AF sends an access stratum time distribution (ASTI) creation request to the NEF to activate a time synchronization service.

[0202] AF can send an ASTI creation request to NEF through the Nnef interface to request activation of the ASTI timing service (exemplarily, through the Nnef_ASTI_Create Req message). The ASTI creation request indicates the information of the target terminal, the device identifier of the terminal device that provides the master clock time for the group to which the target terminal belongs, and the parameters of the 5G access layer time synchronization service. Among them, the device identifier of the terminal device that provides the master clock time for the group can be used to determine the master clock time corresponding to the group. The target terminal can refer to the terminal device requesting timing. The information of the target terminal includes, but is not limited to, a user permanent identifier (SUPI) or a generic public subscription identifier (GPSI) of a terminal, or an external group identifier of a group of terminals.

[0203] The external group identifier is also used to identify a group. Since the AF is unaware of the group's identifier within the communication system, it is referred to here as the external group identifier to distinguish it from the group's identifier within the communication system. The group identifier described above can be understood as the internal group identifier. Alternatively, the external group identifier can be referred to as the off-network group identifier, and the internal group identifier can be referred to as the on-network group identifier. Since the group identifiers discussed below primarily refer to internal group identifiers, unless otherwise specified, the group identifiers can be understood as the internal group identifiers.

[0204] In step 402, the NEF sends an ASTI creation request to the TSCTSF.

[0205] NEF can authorize the request message sent by AF. After successful authorization, NEF converts the external group identifier and internal group identifier according to the information of the target terminal (such as GPSI or external group identifier), further discovers and selects TSCTSF according to the internal group identifier, and then sends an ASTI creation request (Ntsctsf_ASTI_Create Req) to TSCTSF through the Ntsctsf interface to activate 5G access layer time distribution. The ASTI creation request contains the information of the target terminal and the parameters of the 5G access layer time synchronization service.

[0206] In step 403, the NEF requests the UDM to create group information.

[0207] The group information may include group member information, a group identifier (ie, an internal group identifier), and a master clock time corresponding to the group. Group members are the terminal devices included in the group, and group member information is the information of the terminal devices included in the group.

[0208] Exemplarily, NEF sends a group information creation request to UDM through the Nudm interface to request that the group information be saved in UDM (exemplarily, through the Nudm_groupinfo_Create_Req message). The group information creation request includes the information of the target terminal and the parameters of the 5G access layer time synchronization service.

[0209] In response to the group information creation request, the UDM stores the group information, including, for example, group member information, the device identifier of the terminal device providing the master clock time for the group, and the group identifier. After completing the creation of the group information, it sends a group information creation response (Nudm_groupinfo_Create_Resp) to the NEF via the Nudm interface, indicating the success or failure of the UDM storage of the group information.

[0210] In step 404, the TSCTSF obtains the subscription data of the group members from the UDM.

[0211] After receiving the request from AF, TSCTSF can send an SDM acquisition message (Nudm_SDM_Get) to UDM through the Nudm interface to obtain the contract data of group member information from UDM, and further determine whether the timing service requested by AF is allowed.

[0212] In response to the SDM acquisition message, the UDM sends feedback of the acquired group member's subscription data to the TSCTSF through the Nudm interface.

[0213] In step 405, the TSCTSF sends an access and mobility management (AM) policy authorization creation request to the PCF to initiate an AM policy update associated with the terminal device to be timed.

[0214] TSCTSF can send the AM policy authorization creation request (Npcf_AMplicyAuthoriaztion_Create_req) to PCF through the Npcf interface, requesting PCF to enable access layer time synchronization service, Uu time synchronization error budget, clock quality level (i.e., sent by TSCTSF to PCF) and other information according to UE requirements, and further update this information. The AM policy authorization creation request contains the information of the target terminal and the parameters of the 5G access layer time synchronization service.

[0215] In step 406, the PCF and the AMF update the AM policy associated with the terminal device to be timed.

[0216] The AMF requests the PCF to obtain the AM policy. The PCF issues the AM policy to indicate the capabilities that the AMF can provide to the terminal device. For example, what kind of timing service the AMF can provide to the terminal device.

[0217] In step 407, the PCF sends an AM policy authorization creation response to the TSCTSF.

[0218] After the PCF completes the AM policy, it can send an AM policy authorization creation response (Npcf_AMplicyAuthoriaztion_Create_resp) to the TSCTSF through the Npcf interface to indicate the success or failure of the AM policy authorization creation.

[0219] In step 408, the TSCTSF sends an ASTI create response to the NEF.

[0220] TSCTSF may send an ASTI creation response (Ntsctsf_ASTI_Create Resp) to NEF through the Ntsctsf interface to indicate success or failure of ASTI creation.

[0221] In step 409, the NEF sends an ASTI create response to the AF.

[0222] NEF can send an ASTI create response (Nnef_ASTI_Create Resp) to AF through the Nnef interface.

[0223] In step 410, the AMF sends an N2 message to the access network device, where the N2 message includes information about the target terminal and parameters of the 5G access layer time synchronization service.

[0224] In step 302, the access network device sends first system information based on the first message.

[0225] The first message indicates the first group and the terminal device that provides the master clock time for the first group, and the first message is used to request time synchronization for the first group. After receiving the first message, the access network device interacts with the terminal device that provides the master clock time for the first group indicated by the first message, thereby obtaining the master clock time corresponding to the first group. The access network device allocates the master clock time corresponding to the first group to a certain cell for broadcasting. In this embodiment, for the convenience of distinction and explanation, it is assumed that the cell allocated by the access network device to the first group is recorded as the third cell. Since the access network device can provide services for one or more cells, the access network device can send system information in one or more cells it serves. The one or more cells include the third cell and one or more adjacent cells of the third cell.

[0226] Based on the first message, the access network device may send system information #1 (ie, an example of the first system information) in the third cell, for example, by broadcasting the system information #1. Accordingly, the terminal device in the third cell may receive the system information #1.

[0227] The system information #1 includes group timing information of the third cell, as well as at least one neighboring cell of the third cell and at least one group for which each neighboring cell supports timing. The group timing information of the third cell indicates at least one group for which the third cell supports timing and the master clock time corresponding to each group.

[0228] The access network device may also send system information #2 (i.e., another example of the first system information) to one or more neighboring cells of the third cell, for example, by broadcasting the system information #2. Accordingly, terminal devices in each neighboring cell of the third cell may receive the system information #2.

[0229] Here, both System Information #2 and System Information #1 are system information sent by the access network device in the serving cell. The difference is that different cells support different timing groups, and different cells may also have different neighboring cells, so #1 and #2 are used to distinguish them. For example, the neighboring cells of the third cell include the fourth cell, which is also the serving cell of the access network device. Therefore, the access network device can send System Information #2 in the fourth cell, and the terminal device in the fourth cell can receive System Information #2.

[0230] The system information #2 may be used to indicate group timing information of the fourth cell, as well as at least one neighboring cell of the fourth cell and at least one group for which each neighboring cell supports timing. In this embodiment, the fourth cell and the third cell are neighboring cells. Therefore, when system information #2 is used to indicate at least one neighboring cell of the fourth cell and at least one group for which each neighboring cell supports timing, it may indicate the third cell and at least one group for which the third cell supports timing. For example, the at least one group for which the third cell supports timing includes the first group.

[0231] It is understood that the at least one group that the third cell supports timing may include but is not limited to the first group. For ease of understanding, the first group is used as an example for description. The group that the third cell supports timing may also include the second group, the third group, and so on.

[0232] In addition, the first message indicates timing for one group, and may also indicate timing for multiple groups, for example, including but not limited to the first group. The access network device may allocate the master clock time corresponding to the first or multiple groups to the same cell, or to different cells, and this application does not impose any restrictions on this. For each cell allocated to a group, the access network device may indicate the respective group timing information of the cell and the adjacent cells of the cell through system information, as well as the adjacent cells and their groups that support timing, as shown in the above system information #1 and system information #2, which will not be repeated here.

[0233] As previously described, the access network device may include a CU and at least one DU. A possible implementation of step 301 is that the CU receives a first message from a core network element. A possible implementation of step 302 is that, based on the first message, the CU allocates the master clock time corresponding to the first group to the first cell for broadcast, and sends a first configuration update message to at least one DU, indicating the group timing information of the first cell; and the at least one DU that receives the configuration update message sends first system information based on the first configuration update message.

[0234] Exemplarily, step 302 includes steps 3021 to 3022:

[0235] Step 3021: The CU sends a first configuration update message to at least one DU.

[0236] Step 3022: Each DU in the at least one DU sends first system information based on the first configuration update message.

[0237] The following describes these two steps.

[0238] In step 3021, the CU sends a first configuration update message to at least one DU. Correspondingly, the at least one DU receives the first configuration update message from the CU.

[0239] After receiving the first message, the CU allocates the master clock time corresponding to the first group requesting timing to the cell and broadcasts it. In this embodiment, it is assumed that the CU allocates the first group to the third cell. In other words, the third cell can be configured to provide timing for the first group.

[0240] The CU may send a first configuration update message to the first DU to which the third cell belongs, and the first configuration update message may be used to indicate the group timing information of the third cell, as well as at least one adjacent cell of the third cell and the group for which each adjacent cell supports timing. The group timing information of the third cell indicates one or more groups for which the third cell supports timing and the master clock time corresponding to each group. It will be understood that in this embodiment, the group timing information of the third cell changes due to the addition of the first group, and the one or more groups for which the third cell supports timing may include the first group, and the master clock time corresponding to each group may include the master clock time corresponding to the first group.

[0241] The third cell also has one or more neighboring cells, and the CU can notify the neighboring cells of the third cell of changes in the group timing information of the third cell. Since the DUs to which these neighboring cells belong may be the first DU or may not be the first DU, the CU can send the first configuration update message to at least one DU to which it is connected to indicate the group timing information of the serving cell of the at least one DU, as well as the at least one neighboring cell of the serving cell and the group that each neighboring cell supports timing. Among them, the at least one neighboring cell of the serving cell and the group that each neighboring cell supports timing include the third cell and the one or more groups that the third cell supports timing, and the one or more groups that the third cell supports timing include the first group.

[0242] Optionally, the CU may update a locally stored mapping relationship based on the allocation of the master clock time corresponding to the group. The mapping relationship may include a correspondence between one or more cells and one or more groups and one or more master clock times. Each cell in the mapping relationship may support timing for the corresponding group. Each cell may support timing for one group or for multiple groups, which is not limited in this application.

[0243] An example of a mapping relationship pre-stored by a CU may be shown in Table 3A. Assuming that cell #2 in Table 3 below is an example of a third cell, before receiving the first message, the one or more cells in the mapping relationship include cell #1 and cell #2. Cell #1 supports timing groups including group #2, group #3, and group #4. The master clock times corresponding to group #2, group #3, and group #4 are master clock time #2, master clock time #3, and master clock time #4, respectively. Cell #2 supports timing groups including group #5, and group #5 corresponds to master clock time #5.

[0244] Table 3A

[0245] After receiving the first message, since the CU allocates the master clock time corresponding to the first group to the third cell, the pre-stored mapping relationship can be updated based on the allocation of the master clock time corresponding to the first group, that is, the group currently supporting timing corresponding to cell #2 includes the first group. Assuming that the group identifier of the first group is group #1, the updated mapping relationship is shown in Table 3B below. In the updated mapping relationship, the group identifiers of the group supporting timing corresponding to cell #2 include: group #1 and group #5, and the master clock times corresponding to group #1 and group #5 are master clock time #1 and master clock time #5, respectively.

[0246] Table 3B

[0247] In step 3022, the at least one DU sends first system information based on the first configuration update message.

[0248] The CU is connected to one or more DUs, and each DU in at least one DU broadcasts and sends the first system information. For example, each DU can send the first system information by broadcasting, and each terminal device within the coverage of the service cell of the DU will receive the first system information.

[0249] The first system information indicates the group timing information of the serving cell of each DU, as well as at least one neighboring cell of the serving cell and the groups for which each neighboring cell supports timing. The group timing information indicates at least one group for which the serving cell supports timing and the master clock time corresponding to each group.

[0250] Exemplarily, the third cell and the fourth cell are both cells served by DU#1. DU#1 may broadcast system information #1 in the third cell and broadcast system information #2 in the fourth cell.

[0251] Exemplarily, the third cell is the cell served by DU#1, and the fourth cell is the cell served by DU#2. DU#1 can broadcast system information #1 in the third cell, and DU#2 can broadcast system information #2 in the fourth cell.

[0252] For more detailed descriptions of system information #1 and system information #2, please refer to the above text and will not be repeated here.

[0253] It is understood that DU#1 and DU#2 are not limited to transmitting system information in the third and fourth cells, but may also transmit system information in more cells adjacent to the third cell. The DUs transmitting the first system information are not limited to DU#1 and DU#2, but may include more DUs. For the sake of brevity, these are not listed here.

[0254] Optionally, the first message is further used to indicate a valid period of the master clock time of the first group, and the master clock time of the first group is valid within the valid period.

[0255] The validity period may be indicated by the AF to the core network element via a request message. For example, the validity period of the master clock time is indicated in the request message sent by the AF to the core network element.

[0256] For ease of understanding, Figure 5 exemplarily illustrates another possible process of the AF sending a request message to the core network element and the core network element sending the first message. Unlike Figure 4, the first message in Figure 5 is also used to indicate the valid period of the master clock time of the first group.

[0257] In step 501, the AF sends an ASTI creation request to the NEF to activate the time synchronization service.

[0258] The AF can send an ASTI creation request (Nnef_ASTI_Create Req) to the NEF through the Nnef interface. The ASTI creation request includes the first group, the terminal device that provides the master clock time for the first group, the validity period of the master clock time of the first group, and the parameters of the 5G access layer time synchronization service. The master clock time of the first group is effective during the validity period.

[0259] In step 502, the NEF sends an ASTI creation request to the TSCTSF.

[0260] In step 503, the NEF requests the UDM to create group information.

[0261] In step 504, the TSCTSF obtains the subscription data of the group members from the UDM.

[0262] In step 505, the TSCTSF sends an AM policy authorization creation request to the PCF to initiate an AM policy update associated with the UE to be timed.

[0263] In step 506, the PCF and the AMF update the AM policy associated with the terminal device to be timed.

[0264] In step 507, the PCF sends an AM policy authorization creation response to the TSCTSF.

[0265] In step 508, the TSCTSF sends an ASTI create response to the NEF.

[0266] In step 509, the NEF sends an ASTI create response to the AF.

[0267] In step 510, the AMF sends a first message to the access network device.

[0268] The difference from the above step 301 in which the access network device receives the first message from the core network element is that the first message is also used to indicate the valid period of the master clock time of the first group.

[0269] The specific process of step 501 to step 510 is similar to the content of step 401 to step 410. Please refer to the aforementioned step 401 to step 410 and will not be repeated here.

[0270] Optionally, the method further includes step 303: the access network device sends second system information.

[0271] As mentioned above, the above-mentioned first message is also used to indicate the valid period of the first group. When the valid period of the first group is reached, the first group becomes invalid, or in other words, the first group is deleted. Therefore, the access network device no longer needs to provide timing for the terminal devices in the first group, and it is not necessary to carry the group timing information of the first group in the system information. Therefore, the access network device can send a second system information, which is used to indicate the group timing information of the service cell (such as the aforementioned third cell or fourth cell, etc.), as well as at least one adjacent cell of the service cell and the group that each adjacent cell supports timing. It should be noted that, unlike the first system information, the group that supports timing for the third cell indicated by the second system information does not include the first group.

[0272] Similar to step 302, the access network device may transmit the second system information in one or more cells. For example, the access network device may transmit system information #3 (i.e., an example of the second system information) in the third cell, and may also transmit system information #4 (i.e., another example of the second system information) in a cell adjacent to the third cell. A more detailed description of system information #3, system information #4, and the second system information can be found in the above-mentioned system information #1, system information #2, and the first system information, and will not be repeated here.

[0273] A possible implementation of step 303 is: the CU sends a second configuration update message to at least one DU; and each DU in the at least one DU sends second system information based on the second configuration update message.

[0274] Exemplarily, step 303 includes steps 3031 to 3032:

[0275] Step 3031: The CU sends a second configuration update message to at least one DU.

[0276] Step 3032: Each DU in the at least one DU sends second system information based on the second configuration update message.

[0277] The following describes these two steps.

[0278] In step 3031, the CU sends a second configuration update message to at least one DU. Correspondingly, the at least one DU receives the second configuration update message from the CU.

[0279] The CU can send a second configuration update message to the first DU to which the third cell belongs. The second configuration update message can be used to indicate the group timing information of the third cell, as well as at least one adjacent cell of the third cell and the group for which each adjacent cell supports timing. The at least one group for which the third cell supports timing indicated by the group timing information does not include the first group.

[0280] Exemplarily, when the valid period of the master clock corresponding to the third cell expires, the CU updates the locally stored mapping relationship based on the valid period of the master clock of the first group indicated by the first message, and deletes the first group corresponding to the third cell and the master clock time corresponding to the first group in the locally stored mapping relationship. After the CU updates the mapping relationship, at least one group that supports timing with the third cell does not include the first group, which means that the first cell does not support timing with the first group.

[0281] The specific process for receiving the second configuration update message by the DU in each of the one or more neighboring cells of the third cell is similar to step 3021. For details about step 3021, please refer to the relevant description. Unlike the first configuration update message, the second configuration update message indicates that the one or more groups supporting timing for the third cell do not include the first group.

[0282] In step 3032, each DU in the at least one DU sends second system information based on the second configuration update message.

[0283] It should be understood that the first system information and the second system information, etc. are named in order to distinguish the different groups supporting timing of each cell, and should not constitute any limitation to this application.

[0284] The first DU broadcasts second system information to the third cell, where the second system information indicates group timing information of the third cell, and at least one neighboring cell of the third cell and the groups for which timing is supported by each neighboring cell. The group timing information of the third cell indicates at least one group for which timing is supported by the third cell and a master clock time corresponding to each group, where the at least one group for which timing is supported by the third cell does not include the first group.

[0285] In at least the neighboring cells of the third cell, the DU to which each neighboring cell belongs broadcasts the second system information to its serving cell, and the group supported by the first cell in the second system information sent by each DU does not include the first group.

[0286] In another implementation, if the master clock time of a certain group needs to be deleted or cancelled, it can also be achieved through another N2 message.

[0287] Optionally, the method further includes step 304, where the access network device receives a second message (another example of an N2 message) from the core network element, where the second message is used to instruct deletion of the first group and its corresponding master clock time. Accordingly, the core network element sends the second message to the access network device.

[0288] Exemplarily, the second message may carry a group deletion indication, and the group deletion indication may be used to instruct deletion of the first group and its corresponding master clock time.

[0289] The group deletion instruction may be carried in a request message sent by the AF to the core network element, and forwarded by the core network element to the access network device.

[0290] For ease of understanding, Figure 6 exemplarily illustrates a possible process of the AF sending a request message to the core network element and the core network element sending the second message. Unlike Figures 4 and 5, the second message in Figure 6 is used to instruct the deletion of the first group and its corresponding master clock time.

[0291] In step 601, the AF sends an ASTI creation request to the NEF to activate the time synchronization service.

[0292] The AF can send an ASTI creation request (Nnef_ASTI_Create Req) to the NEF through the Nnef interface to activate the time synchronization service request. The ASTI creation request includes the first group, the terminal device that provides the master clock time for the first group, the group deletion indication, and the parameters of the 5G access layer time synchronization service. The group deletion indication is used to indicate the deletion of the first group information and the master clock time corresponding to the first group.

[0293] In step 602, the NEF sends an ASTI creation request to the TSCTSF.

[0294] In step 603, the NEF requests the UDM to create group information.

[0295] In step 604, the TSCTSF obtains the subscription data of the group members from the UDM.

[0296] In step 605, the TSCTSF sends an AM policy authorization creation request to the PCF to initiate an AM policy update associated with the terminal device to be timed.

[0297] In step 606, the PCF and the AMF update the AM policy associated with the terminal device to be timed.

[0298] In step 607, the PCF sends an AM policy authorization creation response to the TSCTSF.

[0299] In step 608, the TSCTSF sends an ASTI create response to the NEF.

[0300] In step 609, the NEF sends an ASTI create response to the AF.

[0301] In step 610, the AMF sends a second message to the access network device.

[0302] The difference from the first message received by the access network device from the core network element in the aforementioned step 301 is that the second message is also used to indicate a group deletion instruction.

[0303] The specific process of step 601 to step 610 is similar to the content of step 401 to step 410. Please refer to the aforementioned steps 401 to step 410 and will not be repeated here.

[0304] Optionally, the method further includes step 305: the access network device sends third system information.

[0305] As mentioned above, the access network device can also receive a second message from the core network network element, and the second message is used to indicate the deletion of the first group and its corresponding master clock time. That is, when the access network device receives the second message, it deletes the first group and its corresponding master clock time. Therefore, the access network device no longer needs to provide time for the terminal devices in the first group, and it is not necessary to carry the group timing information of the first group in the system information. Therefore, the access network device can send a third system information, and the third system information is used to indicate the group timing information of the service cell (such as the aforementioned third cell or fourth cell, etc.), as well as at least one adjacent cell of the service cell and the group that each adjacent cell supports timing. It should be noted that, unlike the first system information, the group that supports timing for the third cell indicated by the third system information does not include the first group.

[0306] Similar to step 302, the access network device may transmit the third system information in one or more cells. For example, the access network device may transmit system information #5 (i.e., one example of the third system information) in the third cell, and may also transmit system information #6 (i.e., another example of the third system information) in a cell adjacent to the third cell. A more detailed description of system information #5, system information #6, and the third system information can be found in the aforementioned system information #1, system information #2, and the first system information, and will not be repeated here.

[0307] A possible implementation of step 305 is: the CU sends a third configuration update message to at least one DU; and each DU in the at least one DU sends third system information based on the third configuration update message.

[0308] Exemplarily, step 302 includes steps 3051 to 3052:

[0309] Step 3051: The CU sends a third configuration update message to at least one DU.

[0310] Step 3052: Each DU in the at least one DU sends third system information based on the third configuration update message.

[0311] The following describes these two steps.

[0312] In step 3051, the CU sends a third configuration update message to at least one DU. Correspondingly, the at least one DU accepts the third configuration update message from the CU.

[0313] The CU may send a third configuration update message to the first DU to which the third cell belongs, and the third configuration update message may be used to indicate the group timing information of the third cell, as well as at least one adjacent cell of the third cell and the group for which each adjacent cell supports timing. The group timing information of the third cell indicates one or more groups for which the third cell supports timing and the master clock time corresponding to each group. It will be understood that in this embodiment, the group timing information of the third cell has changed due to the group deletion indication indicated by the second message, and the at least one group for which the third cell supports timing does not include the first group, and accordingly, the master clock time corresponding to each group also does not include the master clock time corresponding to the first group.

[0314] The third cell also has one or more neighboring cells. The specific content of the third configuration update message received by the DU to which each neighboring cell belongs from the CU is similar to step 3031 in method 300. Please refer to step 3031 in method 300 and will not be repeated here.

[0315] In step 3052, each DU in the at least one DU sends third system information based on the third configuration update message.

[0316] The first DU may broadcast and send third system information to the third cell, where the third system information indicates group timing information of the third cell, as well as at least one neighboring cell of the third cell and the groups for which each neighboring cell supports timing. The group timing information of the third cell indicates at least one group for which the third cell supports timing and the master clock time corresponding to each group, where the at least one group for which the third cell supports timing does not include the first group.

[0317] In at least one neighboring cell of the third cell, the DU to which each neighboring cell belongs broadcasts and sends third system information to its serving cell, and the group of the third cell supporting timing indicated by the third system information sent by each DU does not include the first group.

[0318] Based on the above scheme, when the AF initiates a timing request, the access network device can allocate a cell to the master clock time corresponding to the group requesting timing based on the received first message, and broadcast and send system information (such as the first system information) based on the first message. The system information can not only indicate the groups that the cell supports timing and the master clock time corresponding to each group, but also indicate at least one adjacent cell of the cell and the groups that each adjacent cell supports timing. In this way, even if the terminal device is not in a cell that can provide timing for its group (such as the target group), it can determine a candidate cell that can support timing for its group from the neighboring cells based on the received system information, and thus switch the terminal device to the cell through cell switching or cell reselection; or, the access network device can also determine which cell can support timing for the group of the terminal device requesting timing based on the received first message and the locally pre-stored mapping relationship, and switch the terminal device to the cell. This is conducive to improving the reliability of group timing.

[0319] Based on the method described above in conjunction with FIG3 , when a timing service is available, the terminal can determine whether the cell currently accessed by the terminal device supports timing for the group to which the terminal device belongs based on the system information broadcast by the cell.

[0320] FIG7 is a schematic flow chart of a communication method provided by an embodiment of the present application. Each step in method 700 is described in detail below.

[0321] In step 710, the terminal device receives system information.

[0322] This system information is system information sent by an access network device in a first cell, and can be received by terminal devices in the first cell. This system information indicates group timing information for the first cell, as well as at least one neighboring cell of the first cell and the groups for which each neighboring cell supports timing. The group timing information for the first cell indicates that the first group supports timing for at least one group and the master clock time corresponding to each group. A more detailed description of this system information can be found in the first system information in method 300 above and will not be repeated here.

[0323] In step 720, the terminal device determines, based on the system information, that at least one group for which the first cell supports timing does not include the target group, and the at least one neighboring cell includes one or more candidate cells.

[0324] The target group is the group to which the terminal device belongs. The terminal device can determine whether the at least one group for which the first cell supports timing includes the target group based on the at least one group for which the first cell supports timing indicated by the system information, or in other words, determine whether the at least one group for which the first cell supports timing includes the target group. When determining whether the at least one group for which the first cell supports timing includes the target group, the terminal device can, for example, determine this by comparing the group identifier of the target group with the group identifiers of each group in the at least one group for which the first cell supports timing.

[0325] If the terminal device determines that at least one group for which the first cell supports timing includes the target group, the terminal device may continue to reside in the first cell.

[0326] If the terminal device determines that the target group is not included in the at least one group for which the first cell supports timing, the terminal device can determine that the group identifier of the group for which the at least one adjacent cell supports timing is the same as the group identifier of the target group based on the at least one adjacent cell of the first cell indicated by the system information and the group for which each adjacent cell in the at least one adjacent cell supports timing. In other words, at least one adjacent cell having the same group identifier as the target group can provide timing for the target group, that is, it can provide timing for one or more terminal devices in the target group, thereby completing group timing.

[0327] The terminal device may determine the neighboring cells that support the target group timing as candidate cells. For the convenience of explanation, it is assumed herein that at least one neighboring cell of the first cell includes one or more candidate cells.

[0328] In step 730, the terminal device sends a handover request to the CU. Correspondingly, the CU receives the handover request from the terminal device.

[0329] The handover request carries the cell identifier of each candidate cell in all candidate cells, and the handover request is used to request that the terminal device be handed over from the first cell to one of the one or more candidate cells. Exemplarily, the handover request carries a candidate cell list, and the candidate cell list includes the cell identifiers of the one or more candidate cells. The cell identifier can be, for example, a physical cell identifier (PCI) or other information that can be used to identify a cell, and the present application includes but is not limited to this.

[0330] The CU may determine a target cell for the terminal device based on the received handover request, and then control the terminal device to handover to the target cell. For the convenience of distinction and explanation, the target cell is referred to as the second cell in this document.

[0331] The second cell may be a cell determined by the CU to be available for terminal device handover, and the second cell may support timing for the target group. Therefore, the second cell may be a cell in one or more candidate cells. The CU may determine the second cell based on the signal quality of the one or more candidate cells.

[0332] For example, the CU may send a frequency point to be measured to the terminal device, and select a cell with the best signal quality from one or more candidate cells as the second cell based on the terminal device's measurement result of the signal quality of the cell corresponding to the measured frequency point.

[0333] In one possible design, the frequency point to be measured is a frequency point corresponding to each adjacent cell of the first cell. In another possible design, the frequency point to be measured is a frequency point corresponding to each of the one or more candidate cells.

[0334] The correspondence between the cell and the frequency point may be pre-configured on the DU, and the DU may send the correspondence to the CU via a Setup Request message of the F1 interface.

[0335] The following provides two possible implementations of the CU determining a target cell for a terminal device.

[0336] A possible implementation method is shown in step 740 in the figure: the CU sends the frequency to be measured to the terminal device, where the frequency to be measured is the frequency of the adjacent cell of the first cell; the CU determines the second cell based on the measurement results obtained by the terminal device on the frequency to be measured and the above-mentioned candidate cell list.

[0337] Steps 7401 to 7404 shown in the figure are step 740 shown from the perspective of device interaction. Exemplarily, step 740 may specifically include:

[0338] Step 7401: The CU determines a frequency to be measured based on at least one neighboring cell of the first cell.

[0339] The CU may determine a frequency corresponding to each neighboring cell according to at least one neighboring cell of the first cell, and further determine a frequency corresponding to each neighboring cell in the at least one neighboring cell of the first cell as a frequency to be measured.

[0340] In step 7402, the CU sends first indication information to the terminal device, where the first indication information indicates the frequency point to be measured. Correspondingly, the terminal device receives the first indication information from the CU.

[0341] The first indication information indicates a frequency point to be measured, where the frequency point to be measured is a frequency point corresponding to each adjacent cell in at least one adjacent cell of the first cell.

[0342] Exemplarily, the first indication information may be carried in an RRC reconfiguration message. The CU sends the RRC reconfiguration message to the terminal device. Correspondingly, the terminal device receives the RRC reconfiguration message from the CU.

[0343] Accordingly, the terminal device may send an RRC reconfiguration completion message to the CU, where the RRC reconfiguration completion message indicates that the terminal device has completed the RRC configuration on the network side.

[0344] Optionally, the first indication information may also indicate a measurement value and a preset threshold.

[0345] The measurement quantity indicates an indicator for measuring signal quality. For example, the measurement quantity may be reference signal received power (RSRP), reference signal received quality (RSRQ), or signal to interference plus noise ratio (SINR), etc., and the embodiments of the present application are not limited thereto.

[0346] The preset threshold is used to trigger the start of measurement of the signal quality of at least one neighboring cell of a certain cell, or to trigger the stop of measurement of the signal quality of at least one neighboring cell of a certain cell. For example, when the signal quality of a first cell is higher than the preset threshold, the stop of measurement of the signal quality of at least one neighboring cell of the first cell can be triggered; when the signal quality of the first cell is lower than the preset threshold, the start of measurement of the signal quality of at least one neighboring cell of the first cell can be triggered.

[0347] In step 7403, the terminal device sends a measurement report to the CU. Correspondingly, the CU receives the measurement report from the terminal device.

[0348] The measurement report indicates a measurement result of the signal quality of at least one neighboring cell of the first cell, and the measurement result indicates the signal quality of at least one neighboring cell of the first cell. The measurement report may include a measurement parameter for evaluating signal quality, such as RSRP, RSRQ, or SINR.

[0349] Exemplarily, the measurement report may indicate a measurement result of the signal quality of each neighboring cell in the at least one neighboring cell.

[0350] Step 7404: The CU determines the second cell based on the candidate cells and the measurement report.

[0351] In one example, the CU arbitrarily selects a neighboring cell belonging to the candidate cell from at least one neighboring cell whose measurement result is higher than a preset threshold as the second cell; or, the CU selects the candidate cell with the best signal quality from at least one neighboring cell whose measurement result is higher than a preset threshold as the second cell.

[0352] In another example, the CU arranges the priorities of the adjacent cells corresponding to different frequency points according to the measurement results of the signal quality of at least one adjacent cell of the first cell indicated in the measurement report, and the priority of the adjacent cell with good signal quality is higher than that of the adjacent cell with low signal quality. Starting from the adjacent cell with the highest priority, it is judged in turn whether the adjacent cell corresponding to the frequency point is a candidate cell among one or more candidate cells. If the adjacent cell corresponding to the frequency point is a candidate cell among one or more candidate cells, it can be determined that the adjacent cell corresponding to the frequency point is the second cell; if the adjacent cell corresponding to the frequency point is not a candidate cell among one or more candidate cells, the adjacent cell corresponding to the frequency point of the next priority is judged, and so on.

[0353] Another possible implementation method is shown in step 750 in the figure: the CU sends the frequency to be measured to the terminal device, where the frequency to be measured is the frequency of the above-mentioned one or more candidate cells; the CU determines the second cell based on the measurement results obtained by the terminal device on the frequency to be measured.

[0354] Steps 7501 to 7504 shown in the figure are steps 750 shown from the perspective of device interaction.

[0355] Exemplarily, step 750 may specifically include:

[0356] In step 7501, the CU determines a frequency to be measured based on one or more candidate cells.

[0357] The CU may determine a frequency point corresponding to each candidate cell according to one or more candidate cells, and further determine a frequency point corresponding to each candidate cell in the one or more candidate cells as a frequency point to be measured.

[0358] In step 7502, the CU sends first indication information to the terminal device, where the first indication information indicates a frequency point to be measured. Correspondingly, the terminal device receives the first indication information from the CU.

[0359] The first indication information indicates a frequency point to be measured, where the frequency point to be measured is a frequency point of each candidate cell in one or more candidate cells.

[0360] Step 7503: The terminal device sends a measurement report to the CU. Correspondingly, the CU receives the measurement report from the terminal device.

[0361] The measurement report indicates a measurement result of the signal quality of each candidate cell, where the measurement result indicates the signal quality of each candidate cell in the one or more candidate cells.

[0362] The specific contents of step 7502 to step 7503 can be found in step 7402 to step 7403 and will not be repeated here.

[0363] Step 7504: The CU determines the second cell based on the measurement results.

[0364] Exemplarily, the CU arbitrarily selects a candidate cell as the second cell from at least one candidate cell whose measurement results are higher than a preset threshold; or, the CU selects the candidate cell with the highest signal quality as the second cell based on the measurement results of the signal quality of one or more candidate cells indicated in the measurement report.

[0365] Optionally, the method further includes step 760, where the CU sends second indication information to the terminal device. Correspondingly, the terminal device receives the second indication information from the CU.

[0366] The second indication information instructs the terminal device to switch to a second cell, where the second cell is a cell with the best signal quality among one or more candidate cells, and the cells served by the second DU include the second cell.

[0367] After determining the second cell, the CU sends a request message to the second DU, requesting the second DU to allocate resources for the terminal device. When the resources are successfully allocated, the second DU sends a message to the CU confirming the successful resource allocation. Furthermore, the CU can send a notification message to the first DU, informing the first DU that it does not need to send information to the CU again for resource scheduling. The first DU responds to the CU based on the received notification message and sends a message to the CU indicating success or failure.

[0368] After the CU receives the message indicating that the first DU responds successfully, the CU sends a second indication information to the terminal device.

[0369] Exemplarily, the CU may carry the second indication information through an RRC reconfiguration message, and the second indication information carried by the RRC reconfiguration message may include the PCI of the second cell, and the second indication information indicates that the terminal device is switched from the first cell to the second cell.

[0370] Optionally, the method further includes step 770, where the terminal device switches to the second cell based on the second indication information.

[0371] Exemplarily, after receiving the second indication information, the terminal device initiates random access based on the PCI of the second cell indicated by the second indication information, and switches the terminal device from the first cell to the second cell served by the second DU.

[0372] Based on the above technical solution, when AF initiates a timing request, the terminal device can determine whether the cell currently accessed by the terminal device (such as the first cell) supports timing for the group to which the terminal device belongs (recorded as the target group) based on the received system information, according to the group indicated in the system information that the cell supports timing and the group supported by each adjacent cell. If it does not support, find a cell (recorded as a candidate cell) from the adjacent cells of the cell that can support timing for the target group. The terminal device can initiate a switching request to trigger a cell switch, switching the terminal device to a candidate cell (recorded as the second cell), so that the terminal device can complete the timing service and ensure the reliability of the group timing.

[0373] The process shown in FIG7 above is an implementation method provided for a terminal device in a connected state. The method provided in this application is also applicable to terminal devices in an idle state or an inactive state. For ease of understanding, the following detailed description is provided in conjunction with FIG8.

[0374] FIG8 is another schematic flow chart of the communication method provided by an embodiment of the present application. The steps in method 800 are described in detail below.

[0375] In step 810, the terminal device receives system information.

[0376] The specific process of the terminal device receiving system information is similar to step 710 in method 700. Please refer to the relevant instructions of step 710 in method 700. For more detailed instructions on the system information, please refer to the first system information in the above method 300, which will not be repeated here.

[0377] In step 820, the terminal device determines the priority ranking of the first cell and at least one neighboring cell based on the system information.

[0378] For ease of understanding, the group to which the terminal device belongs can be recorded as the target group. The priority ranking can be that the priority of the cell that supports timing for the target group is higher than the priority of the cell that does not support timing for the target group. In other words, among the first cell and at least one adjacent cell of the first cell, the cell that can support timing for the group that includes the target group has a higher priority; the cell that can support timing for the group that does not include the target group has a lower priority.

[0379] Exemplarily, the group to which the terminal device belongs is group #1, that is, the target group is group #1. The terminal device currently accesses the first cell, and the system information of the first cell can broadcast the timing information of group #2, group #3, and group #4, that is, the first cell can support timing for group #2, group #3, and group #4. An adjacent cell of the first cell is the second cell, and the system information of the second cell can broadcast the timing information of group #1, group #2, and group #3, that is, the second cell can support timing for group #1, group #2, and group #3.

[0380] It can be seen from this that the first cell does not support timing for the target group, while the second cell supports timing for the target group, so the priority of the second cell is higher than that of the first cell.

[0381] When the priority of the first cell is lower than the priority of at least one neighboring cell of the first cell, this situation can be called neighboring cell high priority; when the priority of the first cell is the same as the priority of at least one neighboring cell of the first cell, that is, the first cell supports timing for the target group, and at least one neighboring cell of the first cell also supports timing for the target group, this situation can be called same priority; when the priority of the first cell is higher than at least one neighboring cell of the first cell, this situation can be called neighboring cell low priority.

[0382] Terminal devices can be sorted according to different priorities. For cells of different priorities, terminal devices can evaluate them according to different reselection rules and reselect a cell.

[0383] In step 830, the terminal device performs cell reselection based on priority sorting.

[0384] The following will explain in combination with the above three different situations.

[0385] One possible scenario is that the neighboring cell has a higher priority:

[0386] For ease of understanding and explanation, at least one neighboring cell with a higher priority than the first cell may be recorded as a candidate cell. When the priority of at least one candidate cell is higher than the priority of the first cell, the terminal device may select a candidate cell from the at least one candidate cell as the second cell, and then handover the terminal device from the first cell to the second cell.

[0387] It can be understood that the terminal device can select any candidate cell as the second cell, and can also select which candidate cell to use as the second cell based on the signal quality of at least one candidate cell.

[0388] One possible implementation manner is that the terminal device can select any candidate cell as the second cell.

[0389] Exemplarily, the terminal device may initiate a random handover, select any candidate cell as the second cell, and then handover the terminal device to the second cell.

[0390] Another possible implementation manner is that the terminal device may select a candidate cell with the best signal quality as the second cell.

[0391] In the case of a high priority of a neighboring cell, the terminal device does not consider the signal quality of the first cell and measures the signal quality of at least one candidate cell.

[0392] When the terminal device determines that the signal quality of at least one candidate cell is higher than a preset threshold, the terminal device initiates cell reselection and switches the terminal device from the first cell to a second cell among the at least one candidate cell.

[0393] When the terminal device determines that the signal quality of at least one candidate cell is lower than or equal to a preset threshold, the terminal device needs to determine whether to start or not to start cell reselection based on the priority of the service requested by the terminal device.

[0394] For example, when the basic service of the terminal device is to ensure normal communication, it is necessary to ensure the signal quality of the cell to which the terminal device belongs. In this case, the terminal device chooses not to start cell reselection, that is, to stay in the first cell to ensure the communication needs of the terminal device.

[0395] When the terminal device is most concerned about the timing service, that is, the terminal device prioritizes completing the timing service. In this case, even if the signal quality of the second cell is lower than the preset threshold, the terminal device will still choose to initiate cell reselection, switching the terminal device from the first cell to the second cell to ensure that the terminal device completes the group timing service in the second cell.

[0396] Another possible situation, with the same priority:

[0397] For ease of understanding and explanation, at least one neighboring cell having a priority equal to that of the first cell may be recorded as a candidate cell.

[0398] Under the same priority conditions, if the signal quality of the first cell falls below a preset threshold, the terminal device initiates measurement of the signal quality of the second cell. If the terminal device determines that the signal quality of at least one candidate cell is better than that of the first cell, it may determine the candidate cell as the second cell. The terminal device initiates cell reselection, switching the terminal device from the first cell to the second cell.

[0399] Another possible situation is that the neighboring cell has a low priority:

[0400] In the case of a low priority of a neighboring cell, the terminal device needs to determine whether to start or not to start cell reselection based on the priority of the service requested by the terminal device.

[0401] For example, when the basic service of a terminal device is to ensure normal communication, although the priority of the first cell is high, when the signal quality of the first cell is lower than a preset threshold, the terminal device starts measuring the signal quality of at least one neighboring cell of the first cell. By calculating the signal quality of the neighboring cell, when the signal quality of the at least one neighboring cell is higher than the preset threshold, the terminal device starts cell reselection and switches the terminal device from the first cell to the neighboring cell. The terminal device can re-prioritize within the cell after switching and initiate the cell reselection process.

[0402] When the terminal device wants to ensure the timing service the most, the first cell can support timing for the terminal device, so the terminal device does not start cell reselection and chooses to stay in the first cell to complete the timing service requested by the terminal device.

[0403] Based on the above technical solution, when a terminal device accesses a first cell and is in an idle state or a deactivated state, the terminal device can rearrange the priorities of the first cell and at least one adjacent cell of the first cell based on the received first information, so that the priority of the cell that supports timing for the target group is higher than the priority of the cell that does not support timing for the target group, and the target group is the group to which the terminal device belongs. If the priority of at least one adjacent cell is higher than that of the first cell, the terminal device itself triggers cell reselection and switches the terminal device to the adjacent cell with a higher priority, thereby meeting the service needs of the terminal device for group timing.

[0404] The processes shown in Figures 7 and 8 above are described using terminal judgment as an example. In fact, the solution provided in this application is not limited to this. The access network device can also determine whether the first cell supports timing for the target group based on the group that supports timing in the first cell where the terminal device is currently located, and if not, switch the terminal device to the second cell that supports timing for the target group.

[0405] Figure 9 is another schematic flow chart of a communication method provided by an embodiment of the present application. The communication method 900 shown in Figure 9 may include steps 910 to 930. Each step in the method 900 is described in detail below.

[0406] In step 910, the access network device receives a third message from a core network element.

[0407] When AF requests group timing for a terminal device, the terminal device requesting timing and the target group can be indicated through a request message.

[0408] In response to the request message, the core network element (such as AMF) can send a third message (i.e., an example of an N2 message) to the access network device through the N2 interface to request timing for the terminal device.

[0409] The third message is used to indicate the terminal device requesting timing and the target group, wherein the target group is the group to which the terminal device belongs, and the target group includes one or more terminal devices.

[0410] The terminal device requesting timing indicated by the third message can be identified by a device identifier, and each terminal device has a unique device identifier. In other words, one possible design for the third message to indicate the terminal device requesting timing and the target group is that the third message carries the device identifier of the terminal device requesting timing and the group identifier of the target group. In this communication system, the device identifier is used to identify the terminal device requesting timing, and the group identifier is used to identify the group to which the terminal device requesting timing belongs.

[0411] The process of the core network element sending the third message to the access network device can be referred to steps 401 to 410 in Figure 4, which will not be repeated here. The difference from the first message shown in Figure 4 is that the third message is used to indicate the terminal device requesting timing and the target group.

[0412] In step 920, the access network device determines, based on the third message, at least one group for which the first cell supports timing, and a group for which each of at least one adjacent cell of the first cell supports timing, that the at least one group for which the first cell supports timing does not include the target group, and that at least one adjacent cell includes one or more candidate cells.

[0413] The first cell is the cell where the terminal device requesting timing is currently located, and the candidate cell is the cell that supports timing for the target group.

[0414] The access network device may determine, based on the third message and the at least one group for which the first cell supports timing, whether the at least one group for which the first cell supports timing includes the target group, or in other words, determine whether the at least one group for which the first cell supports timing includes the target group. When the terminal device determines whether the at least one group for which the first cell supports timing includes the target group, the terminal device may determine this by, for example, comparing the group identifier of the target group with the group identifiers of each group in the at least one group for which the first cell supports timing.

[0415] If the access network device determines that at least one group supporting timing in the first cell includes the target group, the terminal device may continue to reside in the first cell.

[0416] If the access network device determines that the target group is not included in at least one group for which the first cell supports timing, the access network device may determine, based on the third message and the group for which each of at least one neighboring cell of the first cell supports timing, that the group identifier of the group for which each neighboring cell supports timing is the same as the group identifier of the target group. In other words, at least one neighboring cell with the same group identifier as the target group can provide timing for the target group, and therefore can provide timing for one or more terminal devices in the target group, thereby completing group timing.

[0417] The terminal device may determine the neighboring cells that support the target group timing as candidate cells. For the convenience of explanation, it is assumed herein that at least one neighboring cell of the first cell includes one or more candidate cells.

[0418] In step 930 , the access network device determines to switch the terminal device from the first cell to a second cell among one or more candidate cells.

[0419] The access network device can switch the terminal device to any candidate cell, or it can switch the terminal device to the candidate cell closest to the first cell, or it can switch the terminal device to the candidate cell with the best signal quality, etc. This application does not impose any restrictions on this.

[0420] One possible implementation manner is that the access network device selects a cell with the best signal quality from the one or more candidate cells as the second cell.

[0421] Optionally, the method also includes: the access network device sends first indication information to the terminal device, the first indication information indicating the frequency of each candidate cell in the one or more candidate cells; the access network device receives a measurement report from the terminal device, the measurement report indicating the measurement result of the signal quality of each candidate cell; the access network device determines the second cell based on the measurement report.

[0422] The specific content of the access network device switching the terminal device to the second cell is similar to step 750 in method 700. Please refer to the relevant description of step 750 in method 700 and will not be repeated here.

[0423] Optionally, the third message is further used to indicate a valid period of the master clock time of the target group, and the master clock time of the target group is effective within the valid period.

[0424] The validity period may be indicated by the AF to the core network element via a request message. For example, the validity period of the master clock time is indicated in the request message sent by the AF to the core network element.

[0425] The process of the AF sending the request message to the core network element and the core network element sending the third message can be seen in steps 501 to 510 in Figure 5, and will not be repeated here. The difference from the first message shown in Figure 5 is that the third message is used to indicate the terminal device requesting timing, the target group, and the validity period of the master clock time of the target group.

[0426] It should be understood that the third message is not limited to indicating the validity period of the master clock time of the target group. The core network element can indicate the group to be deleted to the access network device through the same message (such as the third message). This document only uses the target group as an example for illustration and does not constitute any limitation on this application.

[0427] Optionally, the method further includes: the access network device sending fourth system information.

[0428] As mentioned above, the third message is also used to indicate the valid period of the master clock of the target group. When the valid period is reached, the target group becomes invalid, or in other words, the target group is deleted. Therefore, the access network device no longer needs to provide time for the terminal devices in the target group, and it is not necessary to carry the group timing information of the target group in the system information. Therefore, the access network device can send a fourth system information, which is used to indicate the group timing information of the second cell, as well as at least one adjacent cell of the second cell and the groups that each adjacent cell supports timing. The fourth system information indicates that at least one group that the second cell supports timing does not include the target group. The specific process of the access network device sending the fourth system information is similar to step 303 in method 300. Please refer to the relevant description of step 303 in method 300 and will not be repeated here.

[0429] Another possible implementation of deleting a group is to send a message through a core network element to instruct to delete a certain group.

[0430] Optionally, the method further includes: the access network device receiving a fourth message from the core network element, the fourth message being used to instruct deletion of the target group and its corresponding master clock time. Accordingly, the core network element sends the fourth message to the access network device.

[0431] Exemplarily, the fourth message may carry a group deletion indication, where the group deletion indication is used to instruct deletion of a target group and its corresponding master clock time in at least one group.

[0432] The group deletion instruction may be indicated by the AF to the core network element via a request message. For example, the group deletion instruction is indicated in the request message sent by the AF to the core network element.

[0433] The process of the AF sending the request message to the core network element and the core network element sending the fourth message can be referred to steps 601 to 610 in Figure 6, and will not be repeated here. The difference from the second message shown in Figure 6 is that the fourth message is used to indicate the terminal device requesting timing, the target group, and the group deletion instruction.

[0434] It should be understood that the fourth message is not limited to indicating the deletion of the target group and its corresponding master clock time. The core network element can indicate the group to be deleted to the access network device through the same message (such as the fourth message). This article only uses the target group as an example for illustration and should not constitute any limitation on this application.

[0435] Optionally, after the access network device receives the fourth message, the method further includes: the access network device sending fifth system information.

[0436] As mentioned above, the access network device can also receive a fourth message from the core network network element, and the fourth message is used to indicate the deletion of the target group and its corresponding master clock time. That is, when the access network device receives the fourth message, it deletes the target group and its corresponding master clock time. Therefore, the access network device no longer needs to provide timing for the terminal devices in the target group, and it is not necessary to carry the group timing information of the target group in the system information. Therefore, the access network device can send the fifth system information, and the fifth system information is used to indicate the group timing information of the second cell, as well as at least one adjacent cell of the second cell and the group that each adjacent cell supports timing, and the fifth system information indicates that at least one group that the second cell supports timing does not include the target group.

[0437] The specific process of the access network device sending the fifth system information is similar to step 305 in method 300. Please refer to the relevant description of step 305 in method 300 and will not be repeated here.

[0438] It should be understood that the access network device may indicate that the group supporting timing of the second cell does not include the target group by sending the fourth system information or the fifth system information.

[0439] Based on the above technical solution, when the AF initiates a timing request, the request message sent by the AF to the core network element can carry the terminal device requesting timing and the target group. The core network element can send a third message to the access network device based on the request message, and the access network device can determine whether the group supporting timing of the first cell includes the target group based on the third message and the system information of the first cell accessed by the terminal device requesting timing. If the group supporting timing of the first cell includes the target group but does not include it, and the group supporting timing of one or more candidate cells in at least one adjacent cell of the first cell includes the target group, the access network device initiates a cell handover and switches the terminal device to the candidate cell, so as to meet the service requirements of group timing of the terminal device and help improve the reliability of group timing.

[0440] The method provided by the embodiment of the present application is described in detail above with reference to the accompanying drawings. Below, the device provided by the embodiment of the present application is described in detail with reference to the accompanying drawings.

[0441] Figures 10 to 13 are schematic block diagrams of possible communication devices provided by embodiments of the present application. These communication devices can be used to implement the functions of the terminal device or access network device in the above-mentioned method embodiments, and thus can also achieve the beneficial effects possessed by the above-mentioned method embodiments. In the embodiments of the present application, the communication device can be the terminal device or access network device in the above-mentioned method embodiments, or it can be a component (such as a chip, a chip system, a processor, etc.) configured in the terminal device or access network device, or it can be a logic module or software that can implement some or all of the functions of the terminal device or access network device.

[0442] A communication device provided in this application is shown in FIG10 . The communication device 1000 includes a transceiver module 1010 and a processing module 1020 .

[0443] One possible design is that the communication device 1000 is used to implement the functions of the terminal device in the method embodiments shown in Figure 3, Figure 7 or Figure 8. For example, the device 1000 may correspond to the terminal device in Figure 3, Figure 7 or Figure 8.

[0444] Exemplarily, the transceiver module 1010 is used to receive first system information, which indicates at least one group that the first cell supports timing and the master clock time corresponding to each group, as well as at least one adjacent cell of the first cell and the group that each adjacent cell in the at least one adjacent cell supports timing, the first cell is the cell accessed by the terminal device, the group includes one or more terminal devices, and the master clock time is used to provide timing for each terminal device in the corresponding group; the processing module 1020 is used to determine, based on the first system information, that at least one group that the first cell supports timing does not include a target group, and that the at least one adjacent cell includes one or more candidate cells, the candidate cell is a cell that supports timing for the target group, and the target group is the group to which the terminal device belongs; the transceiver module 1010 is also used to send a switching request, which carries an identifier of each candidate cell in the one or more candidate cells.

[0445] Optionally, the transceiver module 1010 is also used to receive first indication information, which indicates the frequency of each candidate cell in the one or more candidate cells; the processing module 1020 is also used to perform measurements based on the frequency of each candidate cell in the one or more candidate cells to obtain a measurement report, which indicates the measurement results of the signal quality of each candidate cell; the transceiver module 1010 is also used to send the measurement report.

[0446] Optionally, the transceiver module 1010 is also used to receive first indication information, which indicates the frequency of each adjacent cell in the at least one adjacent cell; perform measurement based on the frequency of each adjacent cell in the at least one adjacent cell to obtain a measurement report, which indicates the measurement result of the signal quality of each adjacent cell; and send the measurement report.

[0447] Optionally, the transceiver module 1010 is also used to receive a second indication information, which indicates that the terminal device switches to a second cell, and the second cell is the cell with the best signal quality among the one or more candidate cells; the processing module 1020 is also used to switch to the second cell based on the second indication information.

[0448] Exemplarily, the transceiver module 1010 is also used to receive first system information, which indicates at least one group of timing supported by the first cell and the master clock time corresponding to each group, as well as at least one adjacent cell of the first cell and the group of timing supported by each adjacent cell in the at least one adjacent cell, the first cell is the cell accessed by the terminal device, the group includes one or more terminal devices, and the master clock time is used to provide timing for each terminal device in the corresponding group; the processing module 1020 is also used to determine the priority ranking of the first cell and the at least one adjacent cell based on the first system information, the priority of the cell that supports timing for the target group is higher than the priority of the cell that does not support timing for the target group, and the target group is the group to which the terminal device belongs; the processing module 1020 is also used to perform cell reselection based on the priority ranking.

[0449] Optionally, the processing module 1020 is further configured to, when a priority of a second cell in the at least one neighboring cell is higher than a priority of the first cell, switch to the second cell.

[0450] Optionally, the processing module 1020 is further configured to measure the signal quality of the second cell; the processing module 1020 is further configured to determine that the signal quality of the second cell is higher than a preset threshold.

[0451] One possible design is that the communication device 1000 is used to implement the functions of the access network device in any of the method embodiments shown in Figures 3 to 9. For example, the device 1000 may correspond to the access network device in Figures 3 to 9.

[0452] Exemplarily, the transceiver module 1010 is used to receive a first message from a core network network element, the first message being used to indicate a first group and a terminal device that provides a master clock time for the first group, the master clock time being used to provide timing for each terminal device in the corresponding group; the transceiver module 1010 is also used to send a first system information, the first system information indicating the group timing information of the service cell of the access network device, and at least one adjacent cell of the service cell and a group that each adjacent cell supports timing, the group timing information of the service cell indicating at least one group that the service cell supports timing and the master clock time corresponding to each group, the first group being a group that a third cell supports timing, the third cell being the service cell of the access network device or an adjacent cell of the service cell.

[0453] Optionally, the first message is also used to indicate the valid period of the master clock time of the first group, and the master clock time of the first group is effective during the valid period; the transceiver module 1010 is also used to send second system information, and the group supported by the third cell supported by the second system information does not include the first group.

[0454] Optionally, the transceiver module 1010 is also used to receive a second message from the core network network element, and the second message is used to indicate the deletion of the first group and its corresponding master clock time; the transceiver module 1010 is also used to send third system information, and the group supported by the third cell supported by the third system information does not include the first group.

[0455] Optionally, the transceiver module 1010 is also used to receive a switching request from a terminal device, the switching request carries an identifier of each candidate cell in the one or more candidate cells, and the switching request is used to request that the terminal device be switched from the first cell to one of the one or more candidate cells; the transceiver module 1010 is also used to send a first indication message to the terminal device based on the switching request, the first indication message indicating a frequency to be measured, and the frequency to be measured is the frequency of each candidate cell in the one or more candidate cells; the transceiver module 1010 is also used to receive a measurement report from the terminal device, the measurement report indicating a measurement result of the signal quality of each candidate cell; the processing module 1020 is also used to determine a second cell based on the measurement report, and the second cell is the cell with the best signal quality among the one or more candidate cells.

[0456] Optionally, the transceiver module 1010 is also used to receive a switching request from a terminal device, the switching request carries an identifier of each candidate cell in the one or more candidate cells, and the switching request is used to request that the terminal device be switched from the first cell to one of the one or more candidate cells; the transceiver module 1010 is also used to send a first indication message to the terminal device based on the switching request, the first indication message indicating a frequency to be measured, the frequency to be measured being the frequency of each adjacent cell in at least one adjacent cell of the first cell; the transceiver module 1010 is also used to receive a measurement report from the terminal device, the measurement report indicating a measurement result of the signal quality of each adjacent cell; the processing module 1020 is also used to determine the second cell based on the measurement report and the one or more candidate cells, the second cell being the cell with the best signal quality among the one or more candidate cells.

[0457] In one possible design, the communication device 1000 is used to implement the functions of the CU of the access network device in the method embodiments shown in Figures 3 and 7. For example, the device 1000 may correspond to the CU in the access network device in Figures 3 and 7.

[0458] Exemplarily, the transceiver module 1010 is used to receive a first message from a core network network element, the first message being used to indicate a first group and a terminal device that provides a master clock time for the first group, the master clock time being used to provide timing for each terminal device in the corresponding group; the transceiver module 1010 is also used to send a first configuration update message to at least one second communication unit of the access network device, the first configuration update message indicating the group timing information of the service cell of the second communication unit, and at least one adjacent cell of the service cell and a group that each adjacent cell in the at least one adjacent cell supports timing, the group timing information of the service cell indicating at least one group that the service cell supports timing and the master clock time corresponding to each group, the first group being a group that a third cell supports timing, the third cell being the service cell of the access network device or an adjacent cell of the service cell, the at least one second communication unit including: a second communication unit to which the third cell belongs, and a second communication unit to which at least one adjacent cell of the third cell respectively belongs.

[0459] Optionally, the first message is also used to indicate the valid period of the master clock time of the first group, and the master clock time of the first group is effective during the valid period; the transceiver module 1010 is also used to send a second configuration update message to the at least one second communication unit, and the group of the third cell supporting timing indicated by the second configuration update message does not include the first group.

[0460] Optionally, the transceiver module 1010 is also used to receive a second message from the core network network element, and the second message is used to indicate the deletion of the first group and its corresponding master clock time; the transceiver module 1010 is also used to send a third configuration update message to the at least one second communication unit, and the group supported by the third cell supported by the third configuration update message does not include the first group.

[0461] Optionally, the transceiver module 1010 is also used to receive a switching request from a terminal device, the switching request carries an identifier of each candidate cell in the one or more candidate cells, and the switching request is used to request that the terminal device be switched from the first cell to one of the one or more candidate cells; the transceiver module 1010 is also used to send a first indication message to the terminal device based on the switching request, the first indication message indicating a frequency to be measured, and the frequency to be measured is the frequency of each candidate cell in the one or more candidate cells; the transceiver module 1010 is also used to receive a measurement report from the terminal device, the measurement report indicating a measurement result of the signal quality of each candidate cell; the processing module 1020 is used to determine a second cell based on the measurement report, and the second cell is the cell with the best signal quality among the one or more candidate cells.

[0462] Optionally, the transceiver module 1010 is also used to receive a switching request from a terminal device, the switching request carries an identifier of each candidate cell in the one or more candidate cells, and the switching request is used to request that the terminal device be switched from the first cell to one of the one or more candidate cells; the transceiver module 1010 is also used to send a second indication message to the terminal device based on the switching request, the second indication message indicating a frequency to be measured, the frequency to be measured being a frequency of each adjacent cell in at least one adjacent cell of the first cell; the transceiver module 1010 is also used to receive a measurement report from the terminal device, the measurement report indicating a measurement result of the signal quality of each adjacent cell; the processing module 1020 is also used to determine a second cell based on the measurement report and the one or more candidate cells, the second cell being the cell with the best signal quality among the one or more candidate cells.

[0463] Exemplarily, the transceiver module 1010 is used to receive a third message from a core network network element, the third message indicating a terminal device requesting timing and a target group, the target group being the group to which the terminal device belongs, and the group including one or more terminal devices; the processing module 1020 is used to determine, based on the third message, at least one group for which the first cell supports timing, and a group for which each of at least one adjacent cell of the first cell supports timing, that the at least one group for which the first cell supports timing does not include the target group, and that the at least one adjacent cell includes one or more candidate cells, the candidate cell being a cell that supports timing for the target group, and the first cell being the cell accessed by the terminal device; the processing module 1020 is also used to determine to switch the terminal device to a second cell among the one or more candidate cells.

[0464] Optionally, the second cell is a cell with the best signal quality among the one or more candidate cells.

[0465] Optionally, the transceiver module 1010 is also used to send a first indication information to the terminal device, where the first indication information indicates the frequency of each candidate cell in the one or more candidate cells; the transceiver module 1010 is also used to receive a measurement report from the terminal device, where the measurement report indicates the measurement result of the signal quality of each candidate cell; the processing module 1020 is also used to determine the second cell based on the measurement report.

[0466] Optionally, the third message is further used to indicate a valid period of the master clock time of the target group, and the master clock time of the target group is effective within the valid period.

[0467] Optionally, the transceiver module 1010 is also used to send a fourth configuration update message to at least one second communication unit of the access network device, the fourth configuration update message indicating the group timing information of the second cell, and at least one adjacent cell of the second cell and the group that each adjacent cell in the at least one adjacent cell supports timing, the group timing information of the second cell indicates at least one group that the second cell supports timing and the master clock time corresponding to each group, and the group that the second cell supports timing indicated by the fourth configuration update message does not include the target group.

[0468] Optionally, the transceiver module 1010 is further used to receive a fourth message from the core network element, where the fourth message is used to instruct deletion of the target group and its corresponding master clock time; and deletion of the correspondence between the second cell and the target group.

[0469] Optionally, the transceiver module 1010 is further configured to send a fifth configuration update message to at least one second communication unit, where the group of the second cell supporting timing indicated by the fifth configuration update message does not include the target group.

[0470] In one possible design, the communication device 1000 is used to implement the functions of the DU in the access network device in the method embodiments shown in Figures 3 and 7. For example, the device 1000 may correspond to the second communication unit of the access network device in Figures 3 and 7.

[0471] Exemplarily, the transceiver module 1010 is configured to receive a configuration update message from the first communication unit of the access network device, where the configuration update message indicates group timing information of the third cell, where the group timing information of the third cell indicates at least one group supported by the third cell and a master clock time corresponding to each group, where each group includes one or more terminal devices, and the master clock time is used to provide timing for each terminal device in the corresponding group;

[0472] The transceiver module 1010 is also used to send system information based on the configuration update message, where the system information indicates the group timing information of the service cell of the second communication unit, as well as at least one adjacent cell of the service cell and the group of timing supported by each adjacent cell, and the third cell is the service cell of the second communication unit or an adjacent cell of the service cell.

[0473] In one possible design, the communication device 1000 is used to implement the functions of the core network element in any of the method embodiments shown in Figures 3 to 7 and 9. For example, the device 1000 may correspond to the core network element in Figures 3 to 7 and 9.

[0474] Exemplarily, the processing module 1020 is used to generate a first message, which is used to indicate the first group, the terminal device that provides the master clock time for the first group, and the valid period of the master clock time of the first group. The master clock time is used to provide time for each terminal device in the corresponding group, and the master clock time of the first group is effective during the valid period; the transceiver module 1010 is used to send the first message.

[0475] Exemplarily, the processing module 1020 is used to generate a first message, which is used to indicate the first group and the terminal device that provides the master clock time for the first group, and the master clock time is used to provide time for each terminal device in the corresponding group; the transceiver module 1010 is used to send the first message; the processing module 1020 is used to generate a second message, which is used to indicate the deletion of the first group and its corresponding master clock time; the transceiver module 1010 is used to send the second message.

[0476] A more detailed description of the transceiver module 1010 and the processing module 1020 can be directly obtained by referring to the relevant description of any one of the embodiments shown in FIG. 3 to FIG. 9 , and is not repeated here.

[0477] Figure 11 is another schematic block diagram of a communication device provided in an embodiment of the present application. As shown in Figure 11, device 1100 includes one or more processors 1110. The processor 1110 can be a general-purpose processor or a dedicated processor. For example, it can be a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, and the central processing unit can be used to control the device (such as a vehicle or chip), execute software programs, and process software program data.

[0478] Optionally, in one design, the processor 1110 may include a program (which may also be referred to as code or instruction), which may be executed on the processor 1110, so that the apparatus 1100 performs the method performed by the terminal device, the access network device, the first communication unit of the access network device, or the second communication unit of the access network device in the above method embodiment. In another possible design, the apparatus 1100 includes a circuit (not shown in FIG11 ), which is used to implement the functions of the terminal device, the access network device, the first communication unit of the access network device, the second communication unit of the access network device, and the core network element in the above method embodiment.

[0479] Exemplarily, the processor 1110 can be used to execute computer programs or instructions in the memory to implement the steps performed by the terminal device, the access network device, the first communication unit of the access network device or the second communication unit of the access network device and the core network network element in the method embodiments shown in the embodiments shown in Figures 3 to 9.

[0480] Optionally, the device 1100 may include one or more memories 1120 on which programs (sometimes also referred to as codes or instructions) are stored. The programs can be run on the processor 1110, so that the device 1100 executes the method executed by the terminal device, access network device, the first communication unit of the access network device, or the second communication unit of the access network device in the above embodiments.

[0481] Optionally, data may be stored in the processor 1110 and / or the memory 1120. The processor and the memory may be provided separately or integrated together.

[0482] Optionally, the apparatus 1100 may further include a communication interface 1130. The processor 1110 may also sometimes be referred to as a processing unit, which controls the apparatus (e.g., a RAN node or a terminal device). The communication interface 1130 may also sometimes be referred to as a transceiver unit, a transceiver, a transceiver circuit, or a transceiver, etc., and is configured to implement the transceiver function of the apparatus. For example, the communication interface 1130 may be configured to receive first system information from an access network device.

[0483] Optionally, the apparatus 1100 further includes a communication interface 1130. The processor 1110 and the communication interface 1130 are coupled to each other. It is understood that the communication interface 1130 may be a transceiver or an input / output interface.

[0484] When the apparatus 1100 is used to implement the methods shown in Figures 3 to 9, the processor 1110 may be used to execute the functions of the processing module 1020, and the communication interface 1130 may be used to execute the functions of the transceiver module 1010. Whether the communication interface 1130 is used for sending or receiving may depend on whether the apparatus 1100 is used to perform a sending action or a receiving action in the solution executed.

[0485] When the apparatus 1100 is a chip implemented in a terminal device, the chip implements the functions of the terminal device in the method embodiment described above. The chip of the terminal device receives a signal from another module in the terminal device (such as a radio frequency module or antenna), which may be a signal sent by the access network device to the terminal device; or the chip of the terminal device sends a signal to another module in the terminal device (such as a radio frequency module or antenna), which may be a signal sent by the terminal device to the access network device.

[0486] When the apparatus 1100 is a chip used in an access network device, the chip implements the functions of the access network device in the above method embodiments. The chip of the access network device receives signals from other modules in the access network device, which may be signals sent by a terminal device to the access network device; or the chip of the access network device sends signals to other modules in the access network device, which may be signals sent by the access network device to a terminal device.

[0487] When the apparatus 1100 is a chip used in a first communication unit of an access network device, the chip implements the functions of the first communication unit in the method embodiment described above. The chip of the first communication unit receives signals from other modules in the first communication unit, which may be signals sent by a core network element to the first communication unit; or the chip of the first communication unit sends signals to other modules in the first communication unit, which may be signals sent by the first communication unit to a second communication unit of the access network device.

[0488] When the apparatus 1100 is a chip used in a second communication unit of an access network device, the chip implements the functions of the second communication unit in the above method embodiment. The chip of the second communication unit receives signals from other modules in the second communication unit, which may be signals sent by the first communication unit to the second communication unit; or the chip of the second communication unit sends signals to other modules in the second communication unit, which may be signals sent by the second communication unit to a terminal device.

[0489] When the apparatus 1100 is a chip used in a core network element, the chip implements the functions of the core network element in the method embodiment. The chip receives signals from other modules in the core network element, which may be signals sent by the AF to the core network element; or sends signals to other modules in the core network element, which may be signals sent by the core network element to an access network device.

[0490] It is understandable that when the apparatus 1100 is a terminal device, an access network device, a first communication unit of an access network device, a second communication unit of an access network device, or a core network element, the communication interface 1130 may be a transceiver, specifically including a transmitter and a receiver, where the transmitter is used to send signals and the receiver is used to receive signals. When the apparatus 1100 is a chip applied to a terminal device, an access network device, a first communication unit of an access network device, a second communication unit of an access network device, or a core network element, the communication interface 1130 may be an input / output circuit, where the input circuit may be used for receiving and the output interface may be used for sending.

[0491] Optionally, the device 1100 further includes a power supply circuit, which can be used to supply power to the device 1100 .

[0492] Figure 12 is a schematic diagram of the structure of a terminal device provided in an embodiment of the present application. As shown in Figure 12, the terminal device 1200 can be applied to the system shown in Figure 2 to perform the functions of the terminal device in the method embodiment shown in Figure 3, Figure 7 or Figure 8. As shown in the figure, the terminal device 1200 includes a processor 1201 and a transceiver 1202. Optionally, the terminal device 1200 also includes a memory 1203. The processor 1201, the transceiver 1202 and the memory 1203 can communicate with each other through an internal connection path to transmit control and / or data signals. The memory 1203 is used to store computer programs, and the processor 1201 is used to call and run the computer program from the memory 1203 to control the transceiver 1202 to send and receive signals. Optionally, the terminal device 1200 may also include an antenna 1204 for transmitting the uplink data or uplink control signaling output by the transceiver 1202 via wireless signals.

[0493] The processor 1201 and the memory 1203 may be combined into a processing device, and the processor 1201 is configured to execute program code stored in the memory 1203 to implement the aforementioned functions. In a specific implementation, the memory 1203 may also be integrated into the processor 1201 or independent of the processor 1201. The processor 1201 may correspond to the processing module in FIG. 10 or the processor in FIG. 11 .

[0494] The transceiver 1202 may correspond to the transceiver module in FIG10 or the communication interface in FIG11 . The transceiver 1202 may include a receiver (or receiver, receiving circuit) and a transmitter (or transmitter, transmitting circuit). The receiver is used to receive signals, and the transmitter is used to transmit signals.

[0495] It should be understood that the terminal device 1200 shown in FIG12 is capable of implementing the various processes related to the terminal device in the method embodiments shown in FIG3 , FIG7 , or FIG8 . The operations and / or functions of the various modules in the terminal device 1200 are respectively for implementing the corresponding processes in the aforementioned method embodiments. For details, please refer to the description of the aforementioned method embodiments; to avoid repetition, detailed descriptions are omitted here.

[0496] The processor 1201 can be used to execute the actions implemented within the terminal device described in the previous method embodiments, while the transceiver 1202 can be used to execute the actions of the terminal device sending to or receiving from the access network device described in the previous method embodiments. For details, please refer to the description of the previous method embodiments and will not be repeated here.

[0497] Optionally, the terminal device 1200 may further include a power supply 1205 for providing power to various devices or circuits in the terminal device.

[0498] In addition, in order to make the functions of the terminal device more complete, the terminal device 1200 may also include one or more of an input unit 1206, a display unit 1207, an audio circuit 1208, a camera 1209 and a sensor 1210, and the audio circuit may also include a speaker 1208a, a microphone 1208b, etc.

[0499] Figure 13 is a schematic diagram of the structure of an access network device provided in an embodiment of the present application, for example, a base station. Base station 1300 can be used in the system shown in Figure 2 to perform the functions of the access network device in the method embodiments shown in Figures 3 to 9. As shown, base station 1300 may include one or more of the following: one or more (DU+RU) units 1310 and one or more CUs 1320. CU 1320 can communicate with a next-generation core (NG core). The DU may include at least one antenna 1311, at least one radio frequency unit 1312, at least one processor 1313, and at least one memory 1314. The DU portion is primarily used for transmitting and receiving radio frequency signals, converting radio frequency signals into baseband signals, and performing partial baseband processing. CU 1320 may include at least one processor 1322 and at least one memory 1321. CU 1320 and the DU may communicate via an interface. The control plane (CP) interface may be an Fs-C, such as F1-C, and the user plane (UP) interface may be an Fs-U, such as F1-U. The DU and RU can work together to implement the functions of the physical (PHY) layer. A DU can be connected to one or more RUs. The functions of the DU and RU can be configured in various ways according to the design. For example, the DU is configured to implement the baseband function, and the RU is configured to implement the mid-RF function. For another example, the DU is configured to implement the high-layer functions in the PHY layer, and the RU is configured to implement the low-layer functions and RF functions in the PHY layer. The high-layer functions in the PHY layer may include a part of the functions of the PHY layer, which is closer to the medium access control (MAC) layer, and the low-layer functions in the PHY layer may include another part of the functions of the PHY layer, which is closer to the mid-RF side.

[0500] The CU 1320 is primarily used for baseband processing and base station control. The DU and CU 1320 may be physically located together or physically separated, i.e., a distributed base station. The CU 1320 is the control center of the base station and may correspond to the processing module in FIG10 or the processor in FIG11 , and may also be referred to as a processing unit, primarily for performing baseband processing functions. For example, the CU 1320 may be used to control the base station to execute the operational procedures for the access network device in the above-described method embodiment.

[0501] Specifically, baseband processing on the CU and DU can be divided according to the protocol layers of the wireless network. For example, the functions of the packet data convergence protocol (PDCP) layer and above are set in the CU, while the functions of the protocol layers below the PDCP, such as the radio link control (RLC) layer and the MAC layer, are set in the DU. For another example, the CU implements the functions of the RRC layer and the PDCP layer, while the DU implements the functions of the RLC layer, the MAC layer, and the PHY layer.

[0502] In addition, optionally, the base station 1300 may include one or more radio frequency units (RUs), one or more DUs, and one or more CUs. The DU may include at least one processor 1313 and at least one memory 1314, the RU may include at least one antenna 1311 and at least one radio frequency unit 1312, and the CU may include at least one processor 1322 and at least one memory 1321.

[0503] In one example, the CU 1320 may be composed of one or more single boards, and the multiple single boards may jointly support a wireless access network with a single access indication (such as a 5G network), or may respectively support wireless access networks with different access standards (such as an LTE network, a 5G network, or other networks). The memory 1321 and the processor 1322 may serve one or more single boards. That is, a memory and a processor may be separately set on each single board. It is also possible that multiple single boards share the same memory and processor. In addition, necessary circuits may be provided on each single board. The DU may be composed of one or more single boards, and the multiple single boards may jointly support a wireless access network with a single access indication (such as a 5G network), or may respectively support wireless access networks with different access standards (such as an LTE network, a 5G network, or other networks). The memory 1314 and the processor 1313 may serve one or more single boards. That is, a memory and a processor may be separately set on each single board. It is also possible that multiple single boards share the same memory and processor. In addition, necessary circuits may be provided on each single board.

[0504] It should be understood that base station 1300 shown in Figure 13 is capable of implementing the various processes involving access network devices in the method embodiments shown in Figures 3 to 9 . The operations and / or functions of the various modules in base station 1300 are respectively for implementing the corresponding processes in the aforementioned method embodiments. For details, please refer to the description of the aforementioned method embodiments; to avoid repetition, detailed descriptions are omitted here.

[0505] It should be understood that the base station 1300 shown in FIG13 is only one possible architecture of an access network device and does not constitute any limitation on the present application. The method provided in the present application is applicable to access network devices of other architectures. For example, access network devices including CUs, DUs, and AAUs. The present application does not limit the specific architecture of the access network device.

[0506] It should be understood that Figure 13 is merely an example and not a limitation, and the access network device may not rely on the structure shown in Figure 13. For example, the access network device may also include an AAU, a CU, and / or a DU, or the access network device may also include a BBU and an adaptive radio unit (ARU). This application is not limited to this.

[0507] The CU and / or DU described above can be used to perform the actions implemented within the access network device described in the previous method embodiments, while the AAU can be used to perform the actions described in the previous method embodiments in which the access network device sends to or receives from the terminal device. For details, please refer to the description in the previous method embodiments and will not be repeated here.

[0508] It should be noted that the above method embodiments can be applied to or implemented by a processor. The processor may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiments can be completed by hardware integrated logic circuits in the processor or by software instructions.

[0509] The processor may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0510] The steps of the method disclosed in the embodiments of this application can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium well-known in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above method.

[0511] The memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct RAM bus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0512] The present application also provides a chip system, which includes at least one processor for supporting the implementation of the functions of the terminal device involved in any one of the above method embodiments, or the functions of the access network device, or the first communication unit function of the access network device, or the second communication unit function of the access network device, or the function of the core network network element, for example, sending, receiving or processing the messages and / or information involved in the above method.

[0513] In one possible design, the chip system further includes a memory, which is used to store program instructions and data, and the memory is located inside or outside the processor.

[0514] The chip system can be composed of chips, or can include chips and other discrete devices.

[0515] The present application also provides a computer program product, which includes: a computer program (also referred to as code, or instructions). When the computer program is run, the method executed by the terminal device in the embodiments shown in Figures 3 to 9 is executed, or the method executed by the access network device is executed, or the method executed by the first communication unit of the access network device is executed, or the method executed by the second communication unit of the access network device is executed, or the method executed by the core network network element is executed.

[0516] The present application also provides a computer-readable storage medium storing a computer program (also referred to as code or instructions). When the computer program is executed, the method executed by the terminal device in the embodiments shown in Figures 3 to 9 is executed, or the method executed by the access network device is executed, or the method executed by the first communication unit of the access network device is executed, or the method executed by the second communication unit of the access network device is executed, or the method executed by the core network element is executed.

[0517] The present application also provides a communication system, which includes the aforementioned terminal device, access network device and core network element, and the access network device includes a first communication unit of the access network device and a second communication unit of the access network device.

[0518] The methods provided in the above embodiments can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, they can be implemented in whole or in part in the form of a computer program product. The computer program product may include one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic disk), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0519] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software 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 beyond the scope of this application.

[0520] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0521] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, 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.

[0522] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0523] 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.

[0524] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) 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 a USB flash drive, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

Claims

1. A communication method, characterized in that: include: Receive first system information, where the first system information indicates at least one group for which a first cell supports timing and a master clock time corresponding to each group, and at least one neighboring cell of the first cell and a group for which each of the at least one neighboring cell supports timing, where the first cell is a cell accessed by a terminal device, the group includes one or more terminal devices, and the master clock time is used to provide timing for each terminal device in the corresponding group; Determining, based on the first system information, that at least one group for which the first cell supports timing synchronization does not include a target group, and that the at least one neighboring cell includes one or more candidate cells, where the candidate cells are cells that support timing synchronization for the target group, and the target group is a group to which the terminal device belongs; Sending a handover request, where the handover request carries an identifier of each candidate cell in the one or more candidate cells.

2. The method according to claim 1, wherein The method further comprises: receiving first indication information, where the first indication information indicates a frequency of each candidate cell among the one or more candidate cells; Performing measurement based on a frequency point of each candidate cell among the one or more candidate cells to obtain a measurement report, where the measurement report indicates a measurement result of a signal quality of each candidate cell; Sending the measurement report.

3. The method according to claim 1, wherein The method further comprises: receiving first indication information, where the first indication information indicates a frequency of each of the at least one neighboring cell; Performing measurement based on a frequency point of each neighboring cell in the at least one neighboring cell to obtain a measurement report, where the measurement report indicates a measurement result of a signal quality of each neighboring cell; Sending the measurement report.

4. The method according to any one of claims 1 to 3, characterized in that The method further comprises: receiving second indication information, where the second indication information instructs the terminal device to switch to a second cell, where the second cell is a cell with the best signal quality among the one or more candidate cells; Based on the second indication information, switch to the second cell.

5. A communication method, characterized in that: include: Receive first system information, where the first system information indicates at least one group for which a first cell supports timing and a master clock time corresponding to each group, and at least one neighboring cell of the first cell and a group for which each of the at least one neighboring cell supports timing, where the first cell is a cell accessed by a terminal device, the group includes one or more terminal devices, and the master clock time is used to provide timing for each terminal device in the corresponding group; Determine, based on the first system information, a priority ranking of the first cell and the at least one neighboring cell, where a priority of a cell that supports timing for a target group is higher than a priority of a cell that does not support timing for the target group, where the target group is a group to which the terminal device belongs; Based on the priority ranking, cell reselection is performed.

6. The method according to claim 5, wherein The performing cell reselection based on the priority sorting includes: In a case where the priority of a second cell among the at least one neighboring cell is higher than the priority of the first cell, handover is performed to the second cell.

7. The method according to claim 6, wherein Before switching to the second cell, the method further includes: measuring the signal quality of the second cell; It is determined that the signal quality of the second cell is higher than a preset threshold.

8. A communication method, characterized in that: Applicable to access network equipment, including: receiving a first message from a core network element, the first message being used to indicate a first group and a terminal device that provides a master clock time for the first group, the master clock time being used to provide timing for each terminal device in the corresponding group; Send first system information, where the first system information indicates group timing information of the serving cell of the access network device, and at least one neighboring cell of the serving cell and a group for which each neighboring cell supports timing. The group timing information of the serving cell indicates at least one group for which the serving cell supports timing and a master clock time corresponding to each group. The first group is a group for which a third cell supports timing, and the third cell is the serving cell of the access network device or a neighboring cell of the serving cell.

9. The method according to claim 8, wherein The first message is further used to indicate a valid period of the master clock time of the first group, and the master clock time of the first group is valid during the valid period; The method further comprises: Second system information is sent, where the group of the third cell supporting timing indicated by the second system information does not include the first group.

10. The method according to claim 8, wherein The method further comprises: receiving a second message from the core network element, where the second message is used to instruct deletion of the first group and its corresponding master clock time; Third system information is sent, where the group of the third cell supporting timing indicated by the third system information does not include the first group.

11. The method according to any one of claims 8 to 10, characterized in that The method further comprises: receiving a handover request from a terminal device, the handover request carrying an identifier of each candidate cell in the one or more candidate cells, the handover request being used to request handover of the terminal device from the first cell to one of the one or more candidate cells; Based on the handover request, first indication information is sent to the terminal device, where the first indication information indicates a frequency to be measured, where the frequency to be measured is a frequency of each candidate cell in the one or more candidate cells; receiving a measurement report from the terminal device, the measurement report indicating a measurement result of a signal quality of each candidate cell; A second cell is determined according to the measurement report, where the second cell is a cell with the best signal quality among the one or more candidate cells.

12. The method according to any one of claims 8 to 10, characterized in that The method further comprises: receiving a handover request from the terminal device, the handover request carrying an identifier of each candidate cell in the one or more candidate cells, the handover request being used to request handover of the terminal device from the first cell to one of the one or more candidate cells; Based on the handover request, first indication information is sent to the terminal device, where the first indication information indicates a frequency to be measured, where the frequency to be measured is a frequency of each of at least one neighboring cell of the first cell; receiving a measurement report from the terminal device, the measurement report indicating a measurement result of a signal quality of each neighboring cell; A second cell is determined according to the measurement report and the one or more candidate cells, where the second cell is a cell with the best signal quality among the one or more candidate cells.

13. A communication method, characterized in that: A first communication unit applied to an access network device includes: receiving a first message from a core network element, the first message being used to indicate a first group and a terminal device that provides a master clock time for the first group, the master clock time being used to provide timing for each terminal device in the corresponding group; A first configuration update message is sent to at least one second communication unit of the access network device, wherein the first configuration update message indicates the group timing information of the service cell of the second communication unit, and at least one adjacent cell of the service cell and the group to which each adjacent cell in the at least one adjacent cell supports timing, the group timing information of the service cell indicates at least one group to which the service cell supports timing and the master clock time corresponding to each group, the first group is a group to which a third cell supports timing, the third cell is the service cell of the access network device or an adjacent cell of the service cell, and the at least one second communication unit includes: a second communication unit to which the third cell belongs, and a second communication unit to which at least one adjacent cell of the third cell respectively belongs.

14. The method according to claim 13, wherein The first message is further used to indicate a valid period of the master clock time of the first group, and the master clock time of the first group is valid during the valid period; The method further comprises: A second configuration update message is sent to the at least one second communication unit, where the group of the third cell supporting timing indicated by the second configuration update message does not include the first group.

15. The method according to claim 13, wherein The method further comprises: receiving a second message from the core network element, where the second message is used to instruct deletion of the first group and its corresponding master clock time; A third configuration update message is sent to the at least one second communication unit, where the group of the third cell supporting timing indicated by the third configuration update message does not include the first group.

16. The method according to claim 15, wherein The method further comprises: receiving a handover request from a terminal device, the handover request carrying an identifier of each candidate cell in the one or more candidate cells, the handover request being used to request handover of the terminal device from the first cell to one of the one or more candidate cells; Based on the handover request, first indication information is sent to the terminal device, where the first indication information indicates a frequency to be measured, where the frequency to be measured is a frequency of each candidate cell in the one or more candidate cells; receiving a measurement report from the terminal device, the measurement report indicating a measurement result of a signal quality of each candidate cell; A second cell is determined according to the measurement report, where the second cell is a cell with the best signal quality among the one or more candidate cells.

17. The method according to claim 15, wherein The method further comprises: receiving a handover request from the terminal device, the handover request carrying an identifier of each candidate cell in the one or more candidate cells, the handover request being used to request handover of the terminal device from the first cell to one of the one or more candidate cells; Based on the handover request, first indication information is sent to the terminal device, where the first indication information indicates a frequency to be measured, where the frequency to be measured is a frequency of each of at least one neighboring cell of the first cell; receiving a measurement report from the terminal device, the measurement report indicating a measurement result of a signal quality of each neighboring cell; A second cell is determined according to the measurement report and the one or more candidate cells, where the second cell is a cell with the best signal quality among the one or more candidate cells.

18. A communication method, applied to a first communication unit of an access network device, characterized in that: include: receiving a third message from a core network element, the third message indicating a terminal device requesting timing and a target group, the target group being a group to which the terminal device belongs, the group including one or more terminal devices; Based on the third message, at least one group for which the first cell supports timing, and a group for which each of at least one neighboring cell of the first cell supports timing, determining that the at least one group for which the first cell supports timing does not include the target group, and the at least one neighboring cell includes one or more candidate cells, where the candidate cells are cells that support timing for the target group, and the first cell is a cell accessed by the terminal device; Determine to switch the terminal device to a second cell among the one or more candidate cells.

19. The method according to claim 18, wherein The second cell is a cell with the best signal quality among the one or more candidate cells.

20. The method according to claim 19, wherein Before determining to switch the terminal device to a second cell among the one or more candidate cells, the method further includes: Sending first indication information to the terminal device, where the first indication information indicates a frequency of each candidate cell in the one or more candidate cells; receiving a measurement report from the terminal device, the measurement report indicating a measurement result of a signal quality of each candidate cell; Determine the second cell according to the measurement report.

21. The method according to any one of claims 18 to 20, characterized in that The third message is further used to indicate a valid period of the master clock time of the target group, and the master clock time of the target group is valid during the valid period.

22. The method according to claim 21, wherein The method further comprises: A fourth configuration update message is sent to at least one second communication unit of the access network device, wherein the fourth configuration update message indicates the group timing information of the second cell, and at least one adjacent cell of the second cell and the group for which each adjacent cell in the at least one adjacent cell supports timing, the group timing information of the second cell indicates at least one group for which the second cell supports timing and the master clock time corresponding to each group, and the group for which the second cell supports timing indicated by the fourth configuration update message does not include the target group.

23. The method according to any one of claims 18 to 22, characterized in that After determining to switch the terminal device to a second cell among the one or more candidate cells, the method further includes: receiving a fourth message from the core network element, the fourth message being used to instruct deletion of the target group and its corresponding master clock time; Delete the correspondence between the second cell and the target group.

24. The method according to claim 23, wherein The method further comprises: A fifth configuration update message is sent to the at least one second communication unit, where the group of the second cell supporting timing indicated by the fifth configuration update message does not include the target group.

25. A communication method, characterized in that: A second communication unit applied to an access network device includes: Receiving a configuration update message from the first communication unit of the access network device, the configuration update message indicating group timing information of a third cell, and at least one neighboring cell of the third cell and a group for which each of the at least one neighboring cell supports timing, the group timing information of the third cell indicating at least one group for which the third cell supports timing and a master clock time corresponding to each group, each group including one or more terminal devices, and the master clock time being used to provide timing for each terminal device in the corresponding group; Based on the configuration update message, system information is sent, wherein the system information indicates the group timing information of the service cell of the second communication unit, and at least one adjacent cell of the service cell and the group for which each adjacent cell supports timing, and the third cell is the service cell of the second communication unit or an adjacent cell of the service cell.

26. A communication method, characterized in that: Applicable to core network elements, including: generating a first message, the first message being used to indicate a first group, a terminal device providing a master clock time for the first group, and a valid period of the master clock time of the first group, the master clock time being used to provide timing to each terminal device in the corresponding group, the master clock time of the first group being valid during the valid period; The first message is sent.

27. A communication method, characterized in that: Applicable to core network elements, including: generating a first message, the first message being used to indicate a first group and a terminal device that provides a master clock time for the first group, the master clock time being used to provide timing for each terminal device in the corresponding group; sending the first message; generating a second message, the second message being used to instruct deletion of the first group and its corresponding master clock time; The second message is sent.

28. A communication device, characterized in that: Comprising a module for performing the method according to any one of claims 1 to 4, or, comprising a module for performing the method according to any one of claims 5 to 7, or, comprising a module for performing the method according to any one of claims 8 to 12, or, comprising a module for performing the method according to any one of claims 13 to 17, or, comprising a module for performing the method according to any one of claims 18 to 24, or, comprising a module for performing the method according to any one of claims 25 to 27.

29. A communication device, characterized in that: comprising a processor and a memory, wherein, The memory is used to store computer programs; The processor is used to call the computer program so that the method of any one of claims 1 to 4 is executed, or the method of any one of claims 5 to 7 is executed, or the method of any one of claims 8 to 12 is executed, or the method of any one of claims 13 to 17 is executed, or the method of any one of claims 18 to 24 is executed, or the method of any one of claims 25 to 27 is executed.

30. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 4 is executed, or the method according to any one of claims 5 to 7 is executed, or the method according to any one of claims 8 to 12 is executed, or the method according to any one of claims 13 to 17 is executed, or the method according to any one of claims 18 to 24 is executed, or the method according to any one of claims 25 to 27 is executed.

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