Communication method and communication device

Abstract

The invention provides a communication method and a communication device. The communication method and the communication device are used for solving the conflict problem of different switching processes. The method comprises the following steps: the terminal receives information from a network that the network does not support a first switching mode or the terminal is allowed to use a second switching mode to switch a path, so that the terminal switches a first path to a second path through the second switching mode according to the information. Therefore, the network can control the switching path of the terminal, and conflict between different switching modes is avoided.

Description

Technical Field

[0001] This application relates to the field of communications, and in particular, to a communication method and a communication device. Background Art

[0002] Handovers can support the mobility of user equipment (UE). For example, when a UE moves between different radio access networks (RANs), handovers can enable the UE to switch from a RAN with a poor channel state to a RAN with a better channel state, providing better communication services for users. Handovers include a Handover process and a Path Switch process. Among them, the Handover process is a handover initiated by the network, and the Path Switch process is a handover initiated by the UE actively. However, different handover processes may conflict.

[0003] Therefore, how to avoid conflicts between different handover processes is an urgent problem to be solved. Summary of the Invention

[0004] This application provides a communication method and a communication device, which can solve the conflict problem of different handover processes.

[0005] To achieve the above object, this application adopts the following technical solutions:

[0006] In a first aspect, a communication method is provided, and this method can be executed by a terminal.

[0007] The method includes: The terminal receives first information from the network, where the first information indicates that the network does not support a first handover manner, or indicates that the terminal is allowed to switch paths through a second handover manner; the first handover manner is a handover manner initiated by a radio access network device, and the second handover manner is a handover manner initiated by the terminal; the terminal switches a first path to a second path through the second handover manner according to the first information; the first path includes the connection between the terminal and a first access network device, and the second path includes the connection between the terminal and a second access network device. Switching paths can also be understood as switching from a source RAN (the first access network device) to a target RAN (the second access network device). Exemplarily, the second handover manner is a Path Switch handover. It should be understood that the UE accesses the network through the first path, and the first path includes the first access network device and an access and mobility management network element. The first path may further include a user plane network element. The first path in this embodiment may refer to the user plane path of the UE from the first access network device to the user plane network element, and the first path can also be understood as the path through which the terminal currently transmits data.

[0008] In a possible implementation, the terminal receives the first information from the first path or from other paths different from the first path. For example, the terminal receives the first information during the process of registering to the network. The path through which the terminal registers to the network can be the first path or other paths.

[0009] It can be understood that in this application, the terminal in the first aspect and each aspect below can be a terminal device (such as a mobile phone) or a chip (system) that can be set in the terminal device. That is to say, the communication method in the first aspect can be executed by the terminal device or by the chip (system) in the terminal device.

[0010] Based on the communication method provided in the first aspect, the network sends information for switching paths using the second switching method to the terminal, thereby realizing the control of the terminal's path switching by the network. After receiving the information for switching paths using the second switching method, the terminal switches paths using the second switching method, thereby avoiding conflicts between different switching processes.

[0011] In a possible implementation, switching the first path to the second path using the second switching method according to the first information includes: the terminal sends a session establishment request message or a session modification request message through the second path. The session establishment request message or the session modification request message includes a switching indication and an identifier of the first session. The switching indication is used to indicate switching the first session transmitted on the first path to the second path for transmission; or, the terminal sends a first request through the second path, and the first request is used to request switching the session transmitted on the first path to the second path for transmission. Through the switching indication and the identifier of the first session, switching at the session granularity can be realized, which can be understood as switching a specific session to another path for transmission; or through the first request, switching at the path granularity can be realized, which can be understood as switching all sessions on a certain path to another path for transmission.

[0012] In a possible implementation, before switching the first path to the second path using the second switching method, when the first switching condition is met, the first path is switched to the second path using the second switching method; the first switching condition is that the signal quality between the terminal and the first access network device is lower than the first threshold. Among them, the first threshold can be configured by the first access network device or locally configured by the terminal. When the signal quality is lower than the first threshold, the terminal considers the path between it and the first access network device to be inappropriate, thereby triggering the switching.

[0013] In a possible implementation, the radio access technology (RAT) corresponding to the first access network device is the first RAT, and the RAT corresponding to the second access network device is the second RAT; the first information indicates that the network does not support the first handover method, or indicates that the terminal is allowed to switch paths through the second handover method, including: the first information indicates that the network does not support handover between the first RAT and the second RAT through the first handover method, or indicates that the terminal is allowed to switch between the first RAT and the second RAT through the second handover method.

[0014] In a possible implementation, the first information includes policy information, and the policy information indicates preferential access to the access network device corresponding to the first RAT type. The method further includes: switching the second path to the first path through the second handover method, where the first path includes the connection between the terminal and the first access network device, and the RAT corresponding to the first access network device is the first RAT. By setting a higher-priority RAT, the terminal can transmit data on the path corresponding to the higher-priority RAT as much as possible, thereby ensuring a better communication experience for the user.

[0015] In a possible implementation, switching the second path to the first path through the second handover method includes: when the second handover condition is met, switching the second path to the first path through the second handover method; the second handover condition is that the signal quality between the terminal and the access network device corresponding to the first RAT type is higher than a second threshold. When the terminal determines that the signal quality of the path corresponding to the higher-priority RAT is higher than the second threshold, it switches to transmit data on the corresponding path of the higher-priority RAT. For example, the priority of the sixth generation (6G) is higher than that of the fifth generation (5G). When the terminal determines that the signal quality between it and the access network device corresponding to 6G is higher than the second threshold, it switches to transmit data on the path corresponding to 6G, thereby ensuring that the terminal transmits data on the path with a higher priority as much as possible. Among them, the second threshold can be configured by the access network device or locally configured by the terminal.

[0016] In a second aspect, a communication method is provided. This method can be executed by an access and mobility management network element, or can also be executed by a chip or circuit of the access and mobility management network element. This application does not make any limitations in this regard. For ease of description, the following takes the execution by the access and mobility management network element as an example for illustration.

[0017] The method includes: sending first information to the terminal, where the first information indicates that the network does not support the first handover method, or indicates that the terminal is allowed to switch paths through the second handover method; the first handover method is a handover method initiated by a radio access network device, and the second handover method is a handover method initiated by the terminal; receiving a first request sent by the terminal through a second path, where the first request is used to request to switch the session transmitted through the first path to be transmitted through the second path; the first path includes the connection between the terminal and a first access network device, and the second path includes the connection between the terminal and a second access network device. Handover can also be understood as switching from a source RAN (the first access network device) to a target RAN (the second access network device). Exemplarily, the second handover method is a PathSwitch handover. It should be understood that the UE accesses the network through the first path, and the first path includes a first access network device and an access and mobility management network element. The first path may further include a user plane network element. The first path in this embodiment may refer to the user plane path of the UE from the first access network device to the user plane network element, and the first path can also be understood as the path through which the terminal currently transmits data.

[0018] In the communication method provided in the second aspect, by sending, through an access and mobility management network element, information on switching paths using the second handover method to the terminal, the network can control the terminal's path switching, so that after receiving the information on switching paths using the second handover method, the terminal switches the session transmitted through the first path to be transmitted through the second path using the second handover method, thereby avoiding conflicts between different handover processes.

[0019] In a possible implementation, before sending the first information to the terminal, the method further includes: determining the first information according to the configuration of the network management; or receiving the first information sent by a policy control network element or a data management network element. For example, the network management configures the access and mobility management network element not to support the first handover method, or the policy control network element or the data management network element sends to the access and mobility management network element that the terminal is allowed to switch paths through the second handover method. For another example, the network management configures the access and mobility management network element not to support handover between a first RAT and a second RAT through the first handover method, such as not supporting handover between a terrestrial network (TN) and a non-terrestrial network (NTN) through the first handover method, or not supporting handover between 5G and 6G through the first handover method.

[0020] In a possible implementation, the first request is a session establishment request message or a session modification request message. The session establishment request message or the session modification request message includes a handover indication and an identifier of the first session. The handover indication is used to indicate to switch the first session transmitted on the first path to the second path for transmission. Through the handover indication and the identifier of the first session, handover at the session granularity can be achieved, which can be understood as switching a specific session to another path for transmission.

[0021] In a third aspect, a communication method is provided. This method can be executed by an access network device, or can also be executed by a chip or a circuit of the access network device. This application does not make any limitation in this regard. For the sake of convenience of description, the following takes the execution by the access network device as an example for illustration.

[0022] The method includes: receiving handover policy information, where the handover policy information indicates that the terminal is allowed to switch paths through a second handover method, and the second handover method is a handover method initiated by the terminal; sending handover configuration information to the terminal according to the handover policy information, where the handover configuration information is used for the terminal to switch paths through the second handover method.

[0023] Based on the communication method provided in the third aspect, the access network device receives information that allows the terminal to switch paths through the second handover method, thereby generating handover configuration information for the terminal to switch paths through the second handover method, so that the terminal determines the handover conditions for switching paths through the second handover method according to the handover configuration information. When the handover conditions are met, the terminal switches the session transmitted on the first path to the second path for transmission through the second handover method, thereby avoiding conflicts between different handover processes.

[0024] In a possible implementation, the handover configuration information includes a first handover condition. The first handover condition is used for the terminal to switch paths through the second handover method when the signal quality between the terminal and the access network device is lower than a first threshold. Among them, the first threshold can be configured by the access network device or configured locally by the terminal. When the signal quality is lower than the first threshold, the terminal considers that the path between it and the currently connected access network device is inappropriate, thereby triggering a handover.

[0025] In a possible implementation, the handover configuration information further includes a second handover condition, which is used to hand back to the path corresponding to the above access network device when the signal quality between the terminal and the above access network device is higher than a second threshold. When the terminal determines that the signal quality of the path corresponding to the RAT with a higher priority is higher than the second threshold, it switches to the path corresponding to the RAT with a higher priority to transmit data. For example, the priority of 6G is higher than that of 5G. When the terminal determines that the signal quality between the access network device corresponding to 6G is higher than the second threshold, it switches to the path corresponding to 6G to transmit data, so as to ensure that the terminal transmits data on the path with a higher priority as much as possible. Among them, the second threshold can be configured by the access network device or configured locally by the terminal.

[0026] In a possible implementation, a first piece of information is sent to the terminal, and the first piece of information indicates that the network does not support a first handover method, and the first handover method is a handover method initiated by a radio access network device.

[0027] In a possible implementation, the handover configuration information sent by the access network device to the terminal includes the first piece of information.

[0028] In a possible implementation, the first piece of information is determined according to the configuration of the network management; or, the first piece of information sent by the access and mobility management network element is received. For example, the network management configures the access network device not to support the first handover method, or the access and mobility management network element sends a message to the terminal allowing the terminal to switch paths through the second handover method. For another example, the network management configures the access network device not to support handover between the first RAT and the second RAT through the first handover method, such as not supporting handover between TN and NTN through the first handover method, or not supporting handover between 5G and 6G through the first handover method.

[0029] In a fourth aspect, a communication method is provided, and this method can be executed by a terminal.

[0030] The method includes: the terminal receives a first piece of information from a first network, where the first piece of information indicates that the first network does not support switching paths between the first network and a second network through a first handover method, or indicates that the terminal is allowed to switch paths between the first network and the second network through a second handover method; the first handover method is a handover method initiated by a radio access network device, and the second handover method is a handover method initiated by the terminal; the first path is switched to a second path through the second handover method according to the first piece of information; the first path includes a connection between the terminal and a first access network device, the first access network device corresponds to the first network, and the second path includes a connection between the terminal and a second access network device, and the second access network device corresponds to the second network.

[0031] In a possible implementation, the terminal receives the first information from the first path corresponding to the first network, or receives the first information from other paths different from the first path. For example, the terminal receives the first information during the process of registering to the network, and the path for the terminal to register to the network can be the first path or other paths.

[0032] In the communication method provided in the fourth aspect, information for switching paths between the first network and the second network using the second switching method is sent to the terminal through the network, so as to implement the control of the network over the terminal for switching paths between different networks, such that after receiving the information for switching paths using the second switching method, the terminal switches paths between different networks through the second switching method, thereby avoiding conflicts among different switching processes.

[0033] In a possible implementation, switching the first path to the second path through the second switching method includes: the terminal sends a session establishment request message or a session modification request message through the second path, where the session establishment request message or the session modification request message includes a switching indication and an identifier of the first session, and the switching indication is used to indicate switching the first session transmitted on the first path to be transmitted on the second path; or, the terminal sends a first request through the second path, and the first request is used to request switching the session transmitted on the first path to be transmitted on the second path. Through the switching indication and the identifier of the first session, switching at the session granularity can be achieved, which can be understood as switching a specific session of the first network to be transmitted on the second network; or through the first request, switching at the path granularity can be achieved, which can be understood as switching all sessions on the path corresponding to the first network to be transmitted on the path corresponding to the second network.

[0034] In a possible implementation, before switching the first path to the second path through the second switching method, the method further includes: switching the first path to the second path through the second switching method when the third switching condition is met; the third switching condition is that the signal quality between the terminal and the first access network device is lower than a third threshold. The third threshold can be configured by the first access network device or locally configured by the terminal. When the signal quality is lower than the third threshold, the terminal considers the path between it and the first access network device to be inappropriate, thereby triggering the switching.

[0035] In a possible implementation, the first information includes policy information, and the policy information indicates preferentially accessing the access network device corresponding to the first network. The method further includes: switching the second path to the first path through the second switching method, where the first path includes the connection between the terminal and the first access network device, and the network type corresponding to the first access network device is the first network. By setting a network with a higher priority, the terminal can transmit data on the path corresponding to the network with a higher priority as much as possible, thereby ensuring a better communication experience for the user.

[0036] In a possible implementation, switching the second path to the first path through the second switching method includes: switching the second path to the first path through the second switching method when the fourth switching condition is met; the fourth switching condition is that the signal quality between the terminal and the access network device corresponding to the first network is higher than the fourth threshold. When the terminal determines that the signal quality of the path corresponding to the network with a higher priority is higher than the fourth threshold, it switches to the path corresponding to the network with a higher priority to transmit data. For example, the priority of the first network is higher than that of the second network. When the terminal determines that the signal quality between the access network device corresponding to the first network is higher than the fourth threshold, it switches to the path corresponding to the first network to transmit data, so as to ensure that the terminal transmits data on the path with a higher priority as much as possible. Among them, the fourth threshold can be configured by the access network device or configured locally by the terminal.

[0037] In a fifth aspect, a communication method is provided. This method can be executed by an access and mobility management network element, or can also be executed by a chip or circuit of the access and mobility management network element. This application does not limit this. For the sake of description, the following takes the execution by the access and mobility management network element as an example for illustration.

[0038] The method includes: sending first information to the terminal, where the first information indicates that the first network does not support switching paths between the first network and the second network through the first switching method, or indicates that the terminal is allowed to switch paths between the first network and the second network through the second switching method; the first switching method is a switching method initiated by a radio access network device, and the second switching method is a switching method initiated by the terminal; receiving a first request sent by the terminal through the second path, where the first request is used to request to switch the session transmitted on the first path to the second path for transmission; the first path includes the connection between the terminal and the first access network device, and the second path includes the connection between the terminal and the second access network device. Switching paths can also be understood as switching from the source RAN (the first access network device) to the target RAN (the second access network device). Exemplarily, the second switching method is Path Switch switching. It should be understood that the UE accesses the network through the first path, and the first path includes the first access network device and the access and mobility management network element. The first path may further include a user plane network element. The first path in this embodiment may refer to the user plane path of the UE from the first access network device to the user plane network element, and the first path can also be understood as the path through which the terminal currently transmits data.

[0039] In the communication method provided in the fifth aspect, the access and mobility management network element sends information on switching paths between the first network and the second network using the second handover method to the terminal, thereby realizing the network's control over the terminal's switching of paths between different networks. After the terminal receives the information on switching paths using the second handover method, it switches the session transmitted by the first network to the second network using the second handover method, thereby avoiding conflicts between different handover processes.

[0040] In a possible implementation, before sending the first information to the terminal, the method further includes: determining the first information according to the configuration of the network management; or receiving the first information sent by the policy control network element or the data management network element. For example, the network management configures the access and mobility management network element not to support switching paths between the first network and the second network through the first handover method, or the policy control network element or the data management network element sends to the access and mobility management network element to allow the terminal to switch paths between the first network and the second network through the second handover method.

[0041] In a possible implementation, the first request is a session establishment request message or a session modification request message. The session establishment request message or the session modification request message includes a handover indication and an identifier of the first session. The handover indication is used to indicate switching the first session transmitted on the first path to the second path. Through the handover indication and the identifier of the first session, handover at the session granularity can be realized, which can be understood as switching a specific session of the first network to the second network; or through the first request, handover at the path granularity can be realized, which can be understood as switching all sessions of the corresponding path of the first network to the corresponding path of the second network.

[0042] In a sixth aspect, a communication method is provided. This method can be executed by an access network device, or can also be executed by a chip or circuit of the access network device. This application does not make any limitations in this regard. For the sake of description, the following takes the execution by the access network device as an example for illustration.

[0043] The method includes: receiving handover policy information, where the handover policy information indicates that the terminal is allowed to switch paths between the first network and the second network through the second handover method, and the second handover method is a handover method initiated by the terminal; sending handover configuration information to the terminal according to the handover policy information, where the handover configuration information is used for the terminal to switch paths between the first network and the second network through the second handover method.

[0044] In the communication method provided in the sixth aspect, the access network device receives information allowing the terminal to switch paths between the first network and the second network through the second handover method, and thus generates handover configuration information for the terminal to switch paths through the second handover method, enabling the terminal to determine the handover conditions for switching paths through the second handover method according to the handover configuration information. When the handover conditions are met, the terminal switches the session transmitted by the first network to the second network through the second handover method, thereby avoiding conflicts between different handover processes.

[0045] In a possible implementation, the handover configuration information includes a third handover condition, which is used for the terminal to switch paths through the second handover method when the signal quality between the terminal and the access network device is lower than a third threshold. The third threshold can be configured by the access network device or locally configured by the terminal. When the signal quality is lower than the third threshold, the terminal considers the path between it and the currently connected access network device to be inappropriate, thereby triggering a handover.

[0046] In a possible implementation, the handover configuration information further includes a fourth handover condition, which is used for the terminal to switch back to the path corresponding to the access network device when the signal quality between the terminal and the corresponding access network device is higher than a fourth threshold. When the terminal determines that the signal quality of the path corresponding to the network with a higher priority is higher than the fourth threshold, it switches to transmit data on the path corresponding to the network with a higher priority. For example, if the priority of the first network is higher than that of the second network, and the terminal determines that the signal quality between it and the access network device corresponding to the first network is higher than the fourth threshold, it switches to transmit data on the path corresponding to the first network, thereby ensuring that the terminal transmits data on the path with a higher priority as much as possible. The fourth threshold can be configured by the access network device or locally configured by the terminal.

[0047] In a possible implementation, the first information is sent to the terminal, indicating that the network does not support switching paths between the first network and the second network through the first handover method, and the first handover method is the handover method initiated by the radio access network device.

[0048] In a possible implementation, the handover configuration information sent by the access network device to the terminal includes the first information.

[0049] In a possible implementation, the first information is determined according to the configuration of the network management; or, the first information sent by the access and mobility management network element is received. For example, the network management configures the access network device not to support switching paths between the first network and the second network through the first handover method, or the access and mobility management network element sends information allowing the terminal to switch paths between the first network and the second network through the second handover method.

[0050] In a seventh aspect, a communication method is provided. This method can be executed by an access network device, or alternatively, by a chip or circuit of the access network device. This application does not make any limitations in this regard. For ease of description, the following will take the execution by the access network device as an example for illustration.

[0051] The method includes: receiving handover policy information, where the handover policy information indicates that the terminal is allowed to switch paths through a second handover method, and the second handover method is a handover method initiated by the terminal; according to the handover policy information, sending path handover indication information to the terminal, where the path handover indication information is used for the terminal to switch paths through the second handover method. The first path includes the connection between the terminal and the first access network device, and the second path includes the connection between the terminal and the second access network device.

[0052] In the communication method provided in the seventh aspect, by receiving, through the access network device, the policy information that allows the terminal to switch paths through the second handover method, and sending the handover indication information indicating that the terminal switches paths through the second handover method to the terminal, the network's control over the terminal's path handover is realized, thereby avoiding conflicts in different handover processes.

[0053] In a possible implementation manner, according to the handover policy information, sending path handover indication information to the terminal includes: according to the handover policy information, determining to switch the first path of the terminal to the second path; sending path handover indication information to the terminal.

[0054] In a possible implementation manner, before determining to switch the first path of the terminal to the second path according to the handover policy information, the method further includes: receiving a measurement report sent by the terminal, where the measurement report includes the signal quality of the first cell corresponding to the first access network device, and the signal quality of the first cell is lower than a first threshold corresponding to the second path handover method. Among them, the first threshold can be configured by the first access network device or configured locally by the terminal. When the signal quality is lower than the first threshold, the terminal considers that the path between it and the first access network device is inappropriate, thereby triggering a handover.

[0055] In a possible implementation manner, the measurement report further includes the second cell identifier and the corresponding signal quality, and the signal quality of the second cell is higher than a second threshold. The method further includes: sending the second cell identifier to the terminal, where the second cell identifier indicates the cell information for the terminal to switch to the second path.

[0056] In a possible implementation manner, before sending the handover indication information to the terminal, the method further includes: determining the handover indication information according to the first information, where the first information indicates that the network does not support the first handover method, and the first handover method is a handover method initiated by the radio access network device.

[0057] In a possible implementation, the first information is determined according to the configuration of the network management; alternatively, the first information sent by the access and mobility management network element is received. For relevant descriptions, reference may be made to the relevant descriptions in the third aspect above, which will not be elaborated here.

[0058] In an eighth aspect, a communication method is provided, and this method can be executed by a terminal.

[0059] The method includes: receiving path switching indication information through a first access network device; the terminal switches a first path to a second path through a second switching method according to the path switching indication information; the second switching method is a switching method initiated by the terminal, the first path includes the connection between the terminal and the first access network device, and the second path includes the connection between the terminal and the second access network device.

[0060] Based on the communication method provided in the eighth aspect, switching indication information for switching paths using the second switching method is sent to the terminal through the network, so as to realize the control of the terminal's path switching by the network, so that after receiving the path switching indication information, the terminal switches the path through the second switching method, thereby avoiding conflicts in different switching processes.

[0061] In a possible implementation, before receiving the path switching indication information through the first access network device, the method further includes: the terminal sends capability information, and the capability information indicates that the terminal supports switching paths through the second switching method. By the terminal sending the capability information to the first access network device, the first access network device can determine that the terminal supports the second switching method.

[0062] In a possible implementation, a measurement report is sent to the first access network device, and the measurement report includes the signal quality of the first cell corresponding to the first access network device, the second cell identifier, and the corresponding signal quality; the second cell identifier is received, and the terminal switches to the second cell of the second path according to the second cell identifier.

[0063] In a ninth aspect, a communication method is provided, and this method can be executed by an access network device, or can also be executed by a chip or circuit of the access network device. This application does not make any limitation in this regard. For the convenience of description, the following takes the execution by the access network device as an example for illustration.

[0064] The method includes: receiving switching policy information, where the switching policy information indicates that the terminal is allowed to switch paths between a first network and a second network through a second switching method, and the second switching method is a switching method initiated by the terminal; according to the switching policy information, path switching indication information is sent to the terminal, and the path switching indication information is used for the terminal to switch a first path to a second path through the second switching method, the first path includes the connection between the terminal and the first access network device, and the second path includes the connection between the terminal and the second access network device. The first access network device belongs to the first network, and the second access network device belongs to the second network.

[0065] In the communication method provided in the ninth aspect, the access network device receives policy information that allows the terminal to switch paths between the first network and the second network through the second handover method, and sends handover indication information to the terminal to indicate that the terminal switches paths through the second handover method, so as to implement the network's control over the terminal's path switching, and further avoid conflicts between different handover processes.

[0066] In a possible implementation manner, according to the handover policy information, sending path handover indication information to the terminal includes: determining, according to the handover policy information, to switch the first path of the terminal to the second path; and sending path handover indication information to the terminal.

[0067] In a possible implementation manner, before determining to switch the first path of the terminal to the second path according to the handover policy information, the method further includes: receiving a measurement report sent by the terminal, where the measurement report includes the signal quality of the first cell corresponding to the first access network device, and the signal quality of the first cell is lower than the first threshold corresponding to the second path handover method. The first threshold may be configured by the first access network device or configured locally by the terminal. When the signal quality is lower than the first threshold, the terminal considers that the path between it and the first access network device is inappropriate, thereby triggering a handover.

[0068] In a possible implementation manner, the measurement report further includes the second cell identifier and the corresponding signal quality, and the signal quality of the second cell is higher than the second threshold. The method further includes: sending the second cell identifier to the terminal, where the second cell identifier indicates the cell information for the terminal to switch to the second path.

[0069] In a possible implementation manner, before sending handover indication information to the terminal, the method further includes: determining the handover indication information according to the first information, where the first information indicates that the network does not support switching paths between the first network and the second network through the first handover method, and the first handover method is a handover method initiated by a radio access network device.

[0070] In a possible implementation manner, determining the first information according to the configuration of the network management; or receiving the first information sent by the access and mobility management network element. For relevant descriptions, refer to the relevant descriptions in the third aspect above, which will not be elaborated here.

[0071] In the tenth aspect, a communication method is provided, and this method can be executed by a terminal.

[0072] The method includes: receiving path switching indication information through a first access network device, where the first access network device corresponds to a first network; the terminal switching a first path to a second path according to the path switching indication information through a second switching method, where the second switching method is a switching method initiated by the terminal, the first path includes the connection between the terminal and the first access network device, and the second path includes the connection between the terminal and a second access network device, and the second access network device corresponds to a second network.

[0073] In the communication method provided in the tenth aspect, path switching indication information is sent to the terminal through the network, so as to implement the control of the terminal's path switching by the network, so that after receiving the path switching indication information, the terminal switches the path through the second switching method, thereby avoiding conflicts in different switching processes.

[0074] In a possible implementation, before receiving the path switching indication information through the first access network device, the method further includes: the terminal sending capability information, where the capability information indicates that the terminal supports switching paths between the first network and the second network through the second switching method.

[0075] In a possible implementation, a measurement report is sent to the first access network device, where the measurement report includes the signal quality of the first cell corresponding to the first access network device, the second cell identifier, and the corresponding signal quality; the second cell identifier is received, and the terminal switches to the second cell of the second path according to the second cell identifier.

[0076] In the eleventh aspect, a communication device is provided, and the communication device includes: a module for executing any of the communication methods executed by the terminal described above, such as a transceiver module and a processing module. Wherein, the transceiver module is used to perform corresponding message sending and receiving actions, and the processing module can be used to perform all actions except sending and receiving information.

[0077] Optionally, the communication device described in the eleventh aspect may further include a storage module, and the storage module stores a program or an instruction. When the processing module executes the program or the instruction, the communication device can execute any of the communication methods executed by the terminal described above.

[0078] In the twelfth aspect, a communication device is provided, and the communication device includes: a module for executing any of the communication methods executed by the access and mobility management network element described above, such as a transceiver module and a processing module. Wherein, the transceiver module is used to perform corresponding message sending and receiving actions, and the processing module can be used to perform all actions except sending and receiving information.

[0079] Optionally, the communication device described in the twelfth aspect may further include a storage module that stores programs or instructions. When the processing module executes the programs or instructions, the communication device can execute any of the communication methods performed by the access and mobility management network element described above.

[0080] In a thirteenth aspect, a communication device is provided. The communication device includes: a module for executing any of the communication methods performed by the access network device described above, such as a transceiver module and a processing module. Among them, the transceiver module is used to perform corresponding message sending and receiving actions, and the processing module can be used to perform all actions except sending and receiving information.

[0081] Optionally, the communication device described in the thirteenth aspect may further include a storage module that stores programs or instructions. When the processing module executes the programs or instructions, the communication device can execute any of the communication methods performed by the access network device described above.

[0082] In a fourteenth aspect, a communication device is provided. The communication device includes: a processor that is used to execute instructions stored in a memory so that the communication device performs any of the communication methods performed by the terminal described above.

[0083] In a possible design, the communication device may further include the memory. The memory may be integrated with the processor or may be provided separately.

[0084] In a fifteenth aspect, a communication device is provided. The communication device includes: a processor that is used to execute instructions stored in a memory so that the communication device performs any of the communication methods performed by the access and mobility management network element described above.

[0085] In a possible design, the communication device may further include the memory. The memory may be integrated with the processor or may be provided separately.

[0086] In a sixteenth aspect, a communication device is provided. The communication device includes: a processor that is used to execute instructions stored in a memory so that the communication device performs any of the communication methods performed by the access network device described above.

[0087] In a possible design, the communication device may further include the memory. The memory may be integrated with the processor or may be provided separately.

[0088] In a seventeenth aspect, a communication system is provided, including: a terminal that is used to execute the methods in the first aspect, the fourth aspect, the eighth aspect, and the tenth aspect and any of their possible implementation manners described above.

[0089] Optionally, the communication system further includes an access and mobility management network element, which is configured to execute the methods in the second aspect, the fifth aspect, and any possible implementation manners thereof as described above.

[0090] Optionally, the communication system further includes an access network device, and the radio access network device is configured to execute the methods in the third aspect, the sixth aspect, the seventh aspect, and the ninth aspect, and any possible implementation manners thereof as described above.

[0091] Optionally, the communication system further includes a network management device, a data management network element, or a policy control network element, which is configured to execute the methods in any possible implementation manner of the second aspect or the fifth aspect as described above.

[0092] In the eighteenth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores a computer program or code. When the computer program or code runs on a computer, the computer is caused to execute the methods in any one of the first aspect to the tenth aspect and any possible implementation manner thereof as described above.

[0093] In the sixteenth aspect, a chip is provided, including at least one processor. The at least one processor is coupled to a memory. The memory is configured to store a computer program. The processor is configured to call and run the computer program from the memory, so that a device installed with the chip system executes the methods in any one of the first aspect to the tenth aspect and any possible implementation manner thereof as described above.

[0094] Wherein, the chip may include an input circuit or interface for sending information or data, and an output circuit or interface for receiving information or data.

[0095] In the seventeenth aspect, a computer program product is provided. The computer program product includes computer program code. When the computer program code runs on a computer, the methods in any one of the first aspect to the tenth aspect and any possible implementation manner thereof as described above are executed. BRIEF DESCRIPTION OF THE DRAWINGS

[0096] Figure 1 is a schematic diagram of a communication system provided by an embodiment of the present application.

[0097] Figure 2 is a schematic diagram of the system architecture of Application Scenario 1 provided by the present application;

[0098] Figure 3 is a schematic diagram of the system architecture of Application Scenario 2 provided by the present application;

[0099] Figure 4 is a schematic diagram of a handover scenario provided by an embodiment of the present application;

[0100] FIG. 5(a) is a schematic diagram of a switch based on a first switching method provided by an embodiment of the present application;

[0101] FIG. 5(b) is a schematic diagram of a switch based on a second switching method provided by an embodiment of the present application;

[0102] Figure 6 is a schematic flowchart of a communication method 600 provided by an embodiment of the present application;

[0103] Figure 7 is a schematic flowchart of a communication method 700 provided by an embodiment of the present application;

[0104] Figure 8 is a schematic flowchart of a communication method 800 provided by an embodiment of the present application;

[0105] Figure 9 is a schematic flowchart of a communication method 900 provided by an embodiment of the present application;

[0106] Figure 10 is a schematic structural diagram of a communication device 1000 provided by an embodiment of the present application;

[0107] Figure 11 is a schematic structural diagram of a communication device 2000 provided by an embodiment of the present application;

[0108] Figure 12 is a schematic structural diagram of a chip system 3000 provided by an embodiment of the present application. Detailed implementation manners

[0109] Next, the technical solutions in the present application will be described with reference to the accompanying drawings.

[0110] The technical solutions provided by the present application can be applied to various communication systems, such as: New Radio (NR) systems, Long Term Evolution (LTE) systems, LTE Frequency Division Duplex (FDD) systems, LTE Time Division Duplex (TDD) systems, etc. The technical solutions provided by the present application can also be applied to device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, machine-to-machine (M2M) communication, machine type communication (MTC), and Internet of Things (IoT) communication systems or other communication systems.

[0111] In a communication system, the part operated by an operator can be called a Public Land Mobile Network (PLMN), or it can also be called an operator network, etc. A PLMN is a network established and operated by a government or an operator approved by it for the purpose of providing public land mobile communication services. It is mainly a public network where a Mobile Network Operator (MNO) provides mobile broadband access services to users. In the embodiments of this application, the PLMN described specifically can be a network that meets the standards of the 3rd Generation Partnership Project (3GPP), abbreviated as 3GPP network. A 3GPP network usually includes but is not limited to a 5G network, a 4th-generation (4G) mobile communication network, and other future communication systems, such as a 6G network, etc.

[0112] For ease of description, in the embodiments of this application, the PLMN or 5G network will be used as an example for illustration.

[0113] Figure 1 It is a schematic diagram of a network architecture. Taking the 5G network architecture based on the service-based architecture (SBA) in the non-roaming scenario defined in the 3GPP standardization process as an example. As Figure 1 shown, this network architecture can include a terminal device part, a data network (DN) part, and an operator network PLMN part. Among them, the operator network PLMN part can include but is not limited to a (radio) access network ((R)AN) 120 and a core network (CN) part.

[0114] The functions of the network elements of each part will be briefly described below.

[0115] The terminal device part may include UE 110, which is a device that provides voice and / or data connectivity to users. This UE 110 may also be referred to as a user equipment UE. The UE 110 in this application is a device with wireless transceiver functions and can communicate with one or more CN devices via an access network device (or also referred to as an access device) in the (radio) access network (R)AN 120. The UE 110 may also be called an access terminal, terminal, user unit, user station, mobile station, mobile device, remote station, remote terminal, mobile device, user terminal, user agent, or user device, etc. The UE 110 can be deployed on land, including indoor or outdoor, handheld or vehicle-mounted; it can also be deployed on water (such as on a ship, etc.); it can also be deployed in the air (such as on an airplane, balloon, satellite, etc.). The UE 110 can be a cellular phone, cordless phone, session initiation protocol (SIP) phone, smart phone, mobile phone, wireless local loop (WLL) station, personal digital assistant (PDA), etc. Or, the UE 110 can also be a handheld device with wireless communication functions, a computing device, or other devices connected to a wireless modem, a vehicle-mounted device, a wearable device, a drone device, or a terminal in the Internet of Things, vehicle-to-everything network, any form of terminal in the 5G network and future networks, a relay user equipment, or a terminal in the future evolved 6G network, etc. Among them, the relay user equipment can be, for example, a 5G residential gateway (RG). For example, the UE 110 can be a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in unmanned driving, a wireless terminal in remote medical treatment, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc. The terminal device here refers to a 3GPP terminal. The embodiments of this application do not limit the type or category of the terminal device. For ease of explanation, the subsequent descriptions of this application will use UE to represent the terminal device as an example.

[0116] (R)AN 120 may include one or more access network elements or access network devices. The interface between the access network device and the terminal device may be the Uu interface (or also known as the air interface, that is, the messages exchanged between the access network device and the terminal device may be called air interface messages). Of course, in future communications, the interface name may remain unchanged or may be replaced by other names, and this application does not limit this. (R)AN 120 is a device that provides wireless communication functions for the UE 110, and it can be a node or device that connects the terminal device to the wireless network, and can also be called a network device. (R)AN 120 can be regarded as a sub-network of the operator network and is an implementation system between the service node in the operator network and the UE 110. For example, the UE 110 can be connected to the service node of the operator network through the (R)AN 120 to obtain the services provided by the service node. (R)AN 120 includes but is not limited to: the next generation node base station (gNB) in the 5G system, the evolved node B (eNB) in the long term evolution (LTE), the radio network controller (RNC), the node B (NB), the base station controller (BSC), the base transceiver station (BTS), the home base station (for example, home evolved node B, or home node B, HNB), the base band unit (BBU), the transmitting and receiving point (TRP), the transmitting point (TP), small base station devices, mobile switching centers, or network devices in future networks, etc.The access network device can also be a module or unit that completes the base station function, for example, including a central unit (CU) and a distributed unit (DU); in a possible network architecture, the CU can be used to support communications under protocols such as radio resource control (RRC), packet data convergence protocol (PDCP), and service data adaptation protocol (SDAP); the DU can be used to support communications under the radio link control (RLC) layer protocol, the medium access control (MAC) layer protocol, and the physical layer protocol. The embodiments of the present application do not limit the specific technologies and specific device forms adopted by the access network device. In systems using different radio access technologies, the names of the devices with the functions of the access network device may be different. For ease of description, in all embodiments of the present application, the device that provides wireless communication functions for the above UE 110 is collectively referred to as an access network device or simply RAN for short. It should be understood that the specific types of the access network device are not limited herein.

[0117] The CN part may include but is not limited to the following network functions (NFs): user plane function (UPF) 130, policy control function (PCF) 131, unified data management function (UDM) 132, authentication server function (AUSF) 133, access and mobility management function (AMF) 134, and session management function (SMF) 135.

[0118] The data network DN 140 is usually a network located outside the operator's network, such as a third-party network or an Internet service.

[0119] The NF functions included in the CN are further briefly described below.

[0120] 1. The UPF 130 is a gateway provided by the operator and serves as the gateway for communication between the operator's network and the DN 140. The network functions of the UPF 130 include functions related to the user plane such as packet routing and transmission, packet detection, service usage reporting, quality of service (QoS) handling, uplink packet detection, and downlink packet storage. In future communication systems, the user plane function network element may still be a UPF network element, or it may have other names, which are not limited in this application.

[0121] 2. The PCF 131 is a control plane function provided by the operator, mainly supporting the provision of a unified policy framework to control network behavior, providing policy rules to the control layer network functions, and at the same time being responsible for obtaining user subscription information related to policy decisions. Exemplarily, the PCF 133 can be divided into two PCFs with different functions, namely UE-PCF and AMF-PCF. Among them, the UE-PCF can be used to generate the UE policy, that is, the policy sent to the UE 110, and the sending path is: UE-PCF--->AMF--->UE. At this time, the AMF 134 does not parse the content of the UE policy, that is, the AMF 134 transparently transmits the UE policy. The AM-PCF can be used to generate the AM policy, that is, the policy for access management sent to the AMF 134, and the sending path is: UE-PCF--->AMF. Further, the AMF 134 can also send some or all of the access management policies to the RAN 120. In future communication systems, the policy control function network element may still be a PCF network element, or it may have other names, which are not limited in this application.

[0122] 3. The UDM 132 is a control plane function provided by the operator, responsible for storing information such as the subscriber permanent identifier (SUPI), the generic public subscription identifier (GPSI) of the subscribed user, and the credential in the operator network. Among them, the SUPI will be encrypted first during the transmission process, and the encrypted SUPI is called the subscription concealed identifier (SUCI). The information stored by the UDM network function 132 can be used for the authentication and authorization of the UE 110 to access the operator network. Among them, the subscribed users of the above operator network can specifically be users who use the services provided by the operator network, such as users who use a China Telecom SIM card, or users who use a China Mobile SIM card, etc. The credential of the above subscribed user can be a long-term key stored in the mobile phone chip card or a small file stored with information related to the encryption of the mobile phone chip card, etc., for authentication and / or authorization. In the future communication system, the unified data management functional network element can still be the UDM network element, or, there can also be other names, which are not limited in this application.

[0123] 4. The AUSF 133 is a control plane function provided by the operator, usually used for primary authentication, that is, the authentication between the terminal device 110 (subscribed user) and the operator network. After receiving the authentication request initiated by the subscribed user, the AUSF network function 133 can authenticate and / or authorize the subscribed user through the authentication information and / or authorization information stored in the UDM network function 132, or generate the authentication and / or authorization information of the subscribed user through the UDM network function 132. The AUSF network function 133 can feedback the authentication information and / or authorization information to the subscribed user. In the future communication system, the authentication server functional network element can still be the AUSF network element, or, there can also be other names, which are not limited in this application.

[0124] 5. The AMF 134 is a control plane network function provided by the operator network, responsible for the access control and mobility management of the UE 110 to access the operator network, such as including functions such as mobile status management, allocation of user temporary identity identifiers, authentication and authorization of users, etc. In the future communication system, the access management network element can still be the AMF network element, or, there can also be other names, which are not limited in this application.

[0125] 6. The SMF 135 is a control plane network function provided by the operator network, responsible for managing the protocol data unit (PDU) sessions of the UE 110 (including the establishment, modification, and release of sessions), for the selection and reselection of user plane function network elements, the allocation of Internet Protocol (IP) addresses for terminal devices, quality of service (QoS) control, etc. Among them, the PDU session is a channel for transmitting PDUs, and the PDU session is responsible for establishment, maintenance, deletion, etc. by the SMF network function 135. The SMF network function 135 includes session management (such as session establishment, modification, and release, including tunnel maintenance between the user plane function UPF 130 and the (R)AN 120), selection and control of the UPF network function 130, service and session continuity (SSC) mode selection, roaming, and other session-related functions. In future communication systems, the session management function network element can still be the SMF network element, or it can also have other names, which are not limited in this application.

[0126] It can be understood that the above network elements or functions can be either physical entities in hardware devices, software instances running on dedicated hardware, or virtualized functions instantiated on a shared platform (such as a cloud platform). Simply put, an NF can be implemented by hardware or by software.

[0127] Figure 1 Among them, Npcf, Nudm, Nausf, Namf, Nsmf, N1, N2, N3, N4, and N6 are interface sequence numbers. Exemplarily, the meanings of the above interface sequence numbers can be referred to the meanings defined in the 3GPP standard protocol, and this application does not limit the meanings of the above interface sequence numbers. It should be noted that Figure 1 The interface names between the various network functions in are only examples. In specific implementations, the interface names of this system architecture may also be other names, which are not limited in this application. In addition, the names of the messages (or signaling) transmitted between the above network elements are also only examples and do not impose any limitations on the functions of the messages themselves.

[0128] It should be noted that in Figure 1In the architecture shown, the interface between the radio access network and the 5G core network is called the NG interface (not shown in the figure). gNBs are connected to each other through the Xn interface, and gNBs are connected to the 5GC through the NG interface. Among them, the NG interface includes the NG-C interface and the NG-U interface. The NG-C interface is a control plane interface, connecting the gNB and the AMF, and transmitting control plane data. The NG-U interface is a user plane interface, connecting the gNB and the UPF, and transmitting user plane data. The main functions of the NG interface include but are not limited to: paging, UE context connection, UE mobility management, PDU session management, NAS signaling transmission, etc.

[0129] It should be understood that the above network architecture 100 is only a network architecture described from the perspective of a service-based architecture. In this service-based architecture, the PLMN can, according to specific scenario requirements, orderly combine some or all network functions as needed to realize the customization of network capabilities and services, so as to deploy dedicated networks for different services, that is, to implement 5G network slicing. The network slicing technology enables operators to respond to customer needs more flexibly and quickly and supports the flexible allocation of network resources.

[0130] For ease of description, in the embodiments of the present application, network functions (such as UPF130... SMF135) are collectively / abbreviated as NF, that is, the NF described later in the embodiments of the present application can be replaced by any network function. In addition, in the embodiments of the present application, UE110 is referred to as UE, that is, the UE described later in the embodiments of the present application can be replaced by a terminal device. Figure 1 Only some network functions are schematically described, and the NF described later is not limited to Figure 1 the network functions shown in.

[0131] It should be understood that Figure 1 the AMF, SMF, UPF, AUSF, PCF, and UDM shown in can be understood as network elements in the core network for implementing different functions. For example, they can be combined into network slices as needed. These core network elements can be independent devices or can be integrated into the same device to implement different functions. The present application does not limit the specific forms of the above network elements.

[0132] It should also be understood that the above naming is only defined for the convenience of distinguishing different functions and should not constitute any limitation to the present application. The present application does not exclude the possibility of using other names in 5G networks and future other networks. For example, in 6G networks, some or all of the above network elements may continue to use the terms in 5G, or other names may be used, etc.

[0133] The following introduces several application scenarios involved in the present application:

[0134] Application scenario 1: Please refer to Figure 2 , Figure 2 which is a schematic diagram of the system architecture of Application scenario 1 provided by an embodiment of this application. As Figure 2 shown, the system architecture includes a UE, a first access network device, a second access network device, and a UPF. Figure 2 Taking the system architecture including two access network devices as an example, the system architecture may further include more access network devices, which are not limited in the embodiments of this application. As Figure 2 shown, the UE is connected to the first access network device and the second access network device, and the UE is connected to the same UPF through the first access network device and the second access network device. The first access network device, the second access network device, and the UPF belong to the same PLMN, that is, the first PLMN.

[0135] Among them, the descriptions of the UE and the UPF can be referred to Figure 1 for the relevant explanations of UE 110 and UPF 130 in

[0136] Among them, the first access network device and the second access network device are access network devices of the 3GPP access type. The description of the access network device can be referred to Figure 1 (R)AN 120 in

[0137] The types of radio access technologies (RATs) supported by the first access network device and the second access network device may be the same or different. Or rather, the radio access technologies (RATs) provided by the first access network device and the second access network device may be the same or different.

[0138] For example, the types of radio access technologies may be evolved universal terrestrial radio access (E-UTRA), Non-3GPP, 5G NR, 5G NR (NTN), 6G. Among them, 5G NR can also be referred to as TN NR, and 5G NR (NTN) can be further divided into low earth orbit (LEO), medium earth orbit (MEO), and geostationary earth orbit (GEO). Figure 3 , Figure 3 which is a schematic diagram of the system architecture of Application scenario 2 provided by an embodiment of this application. As Figure 3 shown, the system architecture includes a UE, a first access network device, a second access network device, a first UPF, and a second UPF.Figure 3 Taking the system architecture including two access network devices as an example, the system architecture may further include more access network devices, which is not limited in the embodiments of the present application. For example, Figure 3 As shown, the UE is connected to the first access network device and the second access network device, and the UE is connected to the first UPF through the first access network device and connected to the second UPF through the second access network device. Among them, the first access network device and the first UPF belong to the first PLMN, and the second access network device and the second UPF belong to the second PLMN. The first PLMN and the second PLMN are different. There may also be an interface between the first UPF and the second UPF for data transmission.

[0139] The introduction of the UE, access network device, and UPF in Application Scenario 2 can refer to the description in Application Scenario 1, which will not be elaborated here.

[0140] To facilitate the understanding of the embodiments of the present application, the technologies involved in the embodiments of the present application are briefly introduced below.

[0141] 1. Handover, which can also be referred to as cell handover.

[0142] A cell can be regarded as an area covered by a wireless signal identified by a physical cell identifier (PCI) or a cell global identifier (CGI). The coverage area of each access network device (such as a base station) can be divided into one or more cells. In the embodiments of the present application, different cells can correspond to different base stations, that is, different cells can be managed by different base stations, or different cells can belong to different RANs.

[0143] The above description of the cell is an example rather than a limitation. With the development of technology, concepts that are the same as or similar to the function of the cell may appear, and these concepts are also applicable to the embodiments of the present application.

[0144] Due to the mobility of the UE or the change of the channel state, the cell to which the UE is connected will change, that is, the UE can switch from one cell to another cell. Among them, the cell before the handover can be called the source cell or the anchor cell, and the cell after the handover can be called the target cell. As an optional example, cell handover can be interpreted as the UE performing data transmission on the target cell and stopping data transmission on the source cell, or cell handover can be interpreted as the change of the transmission cell.

[0145] Figure 4 It is a schematic diagram of a handover scenario.

[0146] Figure 4In this case, the UE is currently performing data transmission within the range of the first access network device. As the UE moves in the direction from the first access network device to the second access network device, the channel state of the first access network device deteriorates. The UE can use the cell of the second access network device for data transmission and no longer use the cell of the first access network device for data transmission. Then, the first access network device can be referred to as the source RAN, and the second access network device can be referred to as the target RAN. The process from transmitting data through the source RAN to transmitting data through the target RAN can be called handover.

[0147] 2. Handover can include a first handover method and a second handover method.

[0148] Exemplarily, the first handover method and the second handover method can be applicable to the multi-connection scenario. In the case of two connections, it can also be called the dual-connection scenario, such as dual steer. In the multi-connection scenario, the UE can establish multiple RRC connections with multiple RANs and send or receive data through these multiple RRC connections. If the signal quality of one of the RRC connections is poor, the UE can use other RRC connections for communication. For example, after the UE establishes two RRC connections with RAN1 and RAN2 respectively, if the signal quality of the RRC connection between the UE and RAN1 is poor, the terminal can disconnect the RRC connection with RAN1 and use the RRC connection with RAN2 to transmit data; or, the terminal can no longer use the RRC connection of RAN1 to transmit data, but use the RRC connection of RAN2 to transmit data. Among them, the RRC connection of RAN1 can be retained, and the signaling can continue to be transmitted through the RRC connection of RAN1, or the signaling can be transmitted through the RRC connection of RAN2. These situations can also be called dual-connection handover.

[0149] It should be noted that the first handover method and the second handover method can also be applicable to the single-connection scenario, and the present invention does not limit their usage scenarios.

[0150] The following introduces these two situations separately:

[0151] 2.1. The first handover method, such as handover, can be a handover based on the Xn interface. Fig. 5(a) is a schematic diagram of a handover based on the first handover method provided by an embodiment of the present application, for example, a schematic diagram of a cell handover of the Xn interface. The Xn interface is an interface between the first access network device and the second access network device. If the signal quality of the source cell is poor and the UE needs to hand over to the target cell, then the cell handover based on the Xn interface can be implemented. The source cell can belong to the first access network device, and the target cell can belong to the second access network device. During the cell handover process based on the Xn interface, the AMF serving the UE usually remains unchanged.

[0152] S501, cell handover preparation.

[0153] Before performing the handover, the UE and the source cell need to perform handover preparation operations. For example, the source cell configures the UE to perform a measurement process. The UE measures the signal quality of surrounding cells (including the target cell) according to the measurement configuration and reports the measurement report to the source cell. The source cell decides to perform the handover process for the UE based on the measurement report.

[0154] S502, the source cell sends a RAN Usage data report to the AMF.

[0155] If the PLMN configures the radio access technology (RAT) usage data report for the second RAT, then the source cell can provide the RAN Usage data report to the AMF. This report may include content such as N2 SM Information.

[0156] S503, the target cell sends an N2 Path Switch Request to the AMF.

[0157] The target cell sends an N2 Path Switch Request message to the AMF, notifying the AMF that the UE has moved to the new cell and providing the list of PDU sessions to be handed over. The N2 Path Switch Request message may include content such as N2 SM Information.

[0158] S504, the AMF sends an Nsmf_PDUSession_UpdateSMContextRequest to the SMF.

[0159] After receiving the N2 SM Information from the source cell and the target cell, the AMF caches the relevant information and sends the N2 SM Information to the SMF.

[0160] S505, the SMF sends an N4 Session Modification Request to the UPF.

[0161] According to the network deployment, the CN TunnelInfo of the UPF used to connect the target cell and the source cell may be different. If the CN TunnelInfo of the UPF needs to be reallocated, the CN TunnelInfo is allocated by the SMF. Then the SMF can provide the CN TunnelInfo to the UPF through the N4 Session Modification Request.

[0162] S506. The UPF sends an N4 Session Modification Response to the SMF.

[0163] The UPF may send an N4 Session Modification Response to the SMF after the PDU session corresponding to the N4 session modification request is switched. Optionally, for a PDU session where the user plane resources are not released, if the UPF allocates CN tunnel information and different CN tunnel information needs to be allocated, the UPF may carry the tunnel information of the uplink traffic in the N4 Session Modification Response.

[0164] S507. The UPF sends an N3 End Marker.

[0165] The UPF may send one or more "End Marker" data tables for each N3 tunnel on the old path after the path is switched to assist the target cell in reordering. Subsequently, the UPF may send downlink data to the target cell.

[0166] S508. The SMF sends an Nsmf_PDUSession_UpdateSMContextResponse to the AMF.

[0167] For a successfully switched PDU session, the SMF sends the CN tunnel information to the AMF through the session context response, which is used to establish the N3 tunnel. For a PDU session that deactivates or releases the user plane resources, the session context response sent by the SMF to the AMF does not carry the CN tunnel information, and then the SMF releases the PDU session. S508 can be executed at any time after the SMF receives the N4 Session Modification Response.

[0168] S509. The AMF sends an N2 Path Switch Request Ack to the target cell.

[0169] The N2 Path Switch Request Ack may include contents such as N2 SM Information, Failed PDUSessions, and UE Radio Capability ID. The AMF may write the CN tunnel information therein as part of the N2 SM Information into the N2 Path Switch Request Ack after receiving the session context response and send it to the target cell.

[0170] S510. The target cell instructs the source cell to release resources.

[0171] The target cell may indicate to the source cell that the handover is successful and trigger the source cell to release resources.

[0172] 2.2. The second handover method, such as path switch, allows the UE to initiate the second handover method process. Fig. 5(b) is a schematic diagram of handover based on the second handover method provided by an embodiment of the present application.

[0173] Step 1: The UE establishes a PDU session in RAN1.

[0174] The UE sends a PDU session establishment request message through RAN1. The request message includes the PDU Session ID.

[0175] The AMF selects an SMF, which is responsible for the management of this PDU session.

[0176] The SMF selects a UPF, allocates an IP address for this session and sends it to the UE (so that the UE uses this IP address to send data). This SMF is responsible for configuring the N3 interface between RAN1 and the UPF.

[0177] RAN1 configures the data radio bearer between it and the UE.

[0178] The AMF stores the SMF and the PDU Session ID in the UDM.

[0179] Step 2: The UE establishes a PDU session through RAN2.

[0180] The UE selects RAN2 and sends a PDU session establishment request message through RAN2. The request message includes the PDU Session ID and a handover indication.

[0181] After receiving the request message, the AMF obtains the SMF corresponding to this PDU Session ID from the UDM.

[0182] The SMF continues to maintain the IP address of this PDU session unchanged (that is, the UE can continue to use this IP address to send data without change). This SMF is then responsible for configuring the N3 interface between RAN2 and the UPF (so that the UPF sends the downlink data of the UE to RAN2 instead of RAN1).

[0183] RAN2 configures the data radio bearer between it and the UE (so that the UE sends the uplink data to RAN2 instead of RAN1).

[0184] During the path switch process, the source base station does not need to interact with the target base station, that is, there is no need for an Xn interface.

[0185] During the path switching process, the UE initiates the PDU session establishment procedure of step 2 actively, carrying a handover indication.

[0186] In the handover process, since both the first handover method and the second handover method (such as the Handover process and the PathSwitch process) can support the change of the data transmission path when the UE moves. However, if the coordination of the two processes is not well done, there may be conflict problems. For example, when the UE moves from RAN1 to RAN2, RAN1 wants to hand over the UE to RAN2 through the Handover process, but the UE itself switches to RAN2 through the Path Switch process. However, there may be conflicts between different handover processes. The Handover process is initiated by the network, and the Path Switch process is initiated by the UE actively. The network controls the UE to perform path switching to avoid conflicts between the two handover methods.

[0187] The first handover method requires Xn interface configuration. From the perspective of deployment, the Handover process within the same PLMN requires Xn interface (the interface between RANs) configuration. For example, when the satellite access ground station and the base station are far apart, there may not be an Xn interface configuration between the satellite access ground station and the base station; the Handover process between different PLMNs requires AMF - to - AMF interface configuration. For example, when the source RAN and the target RAN belong to different equipment vendors or the source AMF and the target AMF belong to different equipment vendors, the configuration is difficult. Therefore, in the case of no Xn interface configuration, the handover can be performed through the second handover method.

[0188] To solve the above problems, the following method is proposed in this embodiment.

[0189] As Figure 6 shown, a method 600 applicable to this application is introduced. This method can be applicable to Figure 2 the application scenario 1 described. Through the method 600, the network instructs the UE to allow path switching through the Path Switch, enabling the UE to initiate path switching, thereby ensuring that the Handover process and the Path Switch process are coordinated without conflicts. This method includes the following steps:

[0190] Step 600: The access network device and / or the AMF obtain information that does not support the first handover method.

[0191] In a possible implementation, the network management operations, administration, and maintenance (OAM) configures the access network device and / or the AMF not to support the first handover method (for example, handover not supported). The access network device includes a first access network device and a second access network device. The first handover method is a handover method initiated by a radio access network device (such as handover). For example, the reason for not supporting the first handover method may be that there is no Xn interface configuration.

[0192] In another possible implementation, the access network device and / or the AMF locally configures information indicating that the first handover method is not supported.

[0193] In a possible implementation, the information indicating that the first handover method is not supported means not supporting handover between a first RAT and a second RAT through the first handover method. The first RAT and the second RAT can refer to any two RATs, such as between TN and NTN, or between 5G and 6G.

[0194] In a possible implementation, the access network device and / or the AMF obtains information allowing the UE to switch paths through a second handover method. Alternatively, the information indicating that the first handover method is not supported can indicate that the UE is allowed to switch paths through the second handover method. Exemplarily, it indicates that the UE is allowed to switch paths between a first RAT and a second RAT through the second handover method. The second handover method is a handover method initiated by the UE (such as path switch).

[0195] This embodiment is described by taking the RAT type of the first access network device as TN and the RAT type of the second access network device as NTN as an example.

[0196] Exemplarily, the OAM configures "TN / NTN handover not supported" for the first access network device and / or the AMF, or supports the UE to switch paths through the TN / NTN path (TN / NTN path switch supported).

[0197] Step 601: The UE sends a registration request message to the AMF through the first access network device.

[0198] This registration request message is used for the UE to register with the network by connecting to the first access network device and the AMF. Accordingly, the AMF is responsible for the registration management of this UE.

[0199] It should be understood that the UE accesses the network through a first path, and the first path includes the first access network device and the AMF.

[0200] It should be noted that the first path may further include a UPF. The first path in this embodiment may refer to the user plane path of the UE from the first access network device to the UPF.

[0201] Optionally, the registration request message includes the UE's ability information to support path switching through the second switching method. For example, it is to support path switch support.

[0202] Step 602 (optional): The first network element sends switching policy information to the first access network device.

[0203] The switching policy information indicates that the UE is allowed to switch paths through the second switching method. Exemplarily, the switching policy information is a path switch policy.

[0204] In a possible implementation, the first network element may be a PCF or a UDM. The PCF / UDM sends the switching policy information to the first access network device through the AMF. For example, the PCF / UDM sends the switching policy information to the AMF, and the AMF sends the switching policy information to the first access network device.

[0205] In a possible implementation, when the first network element determines that the UE is allowed to switch paths through the second switching method according to the UE's subscription data, it sends the switching policy information to the first access network device.

[0206] In a possible implementation, the switching policy information includes indication information that allows the UE to switch paths between the first RAT and the second RAT through the second switching method. It can be understood that this indication information can trigger the first access network device to send switching configuration information to the UE.

[0207] In a possible implementation, the switching policy information includes that the network allows the UE to initiate path conversion. For example, the UE can initiate path conversion between the TN RAT and the NTN RAT; or the UE can initiate path switching between the TN frequency and the NTN frequency. At this time, the UE does not need to sense the RAT type, but only needs to sense the corresponding frequency point and perform measurements and cell access on this frequency point.

[0208] In a possible implementation, the switching policy information includes the RAT with priority access. For example, the TN RAT is the primary access and the NTN RAT is the secondary access, so that the UE preferentially accesses the TN cell. Or the 6G RAT is the primary access and the 5G RAT is the secondary access, so that the UE preferentially accesses the 6G cell.

[0209] Step 603 (optional): The first access network device sends handover configuration information to the UE.

[0210] The handover configuration information is used for the UE to switch paths through the second handover method. Exemplarily, the handover configuration information is a path switch configuration.

[0211] In a possible implementation, the first access network device determines the handover configuration information according to the handover policy information. Alternatively, the first access network device determines the handover configuration information according to the information obtained in step 600.

[0212] In a possible implementation, the first access network device sends the handover configuration information by broadcasting. It can be understood that at this time, the first access network device does not need to receive the handover policy information according to step 602, and determines the handover configuration information according to the information obtained in step 600.

[0213] In another possible implementation, the first access network device unicasts the handover configuration information to the UE.

[0214] In a possible implementation, the handover configuration information includes a first handover condition, and optionally, a first threshold. The first handover condition is to switch paths when the signal quality between the UE and the access network device is lower than the first threshold. For example, the access network device may be an access network device of the first RAT type, and the value of the first threshold set may be lower than the threshold for path switching between the first RAT types, such as the threshold for TN to TN handover, so as to avoid conflicts between TN to TN handover and TN to NTN handover, that is, the threshold for TN to NTN handover is lower than the threshold for TN to TN handover, so that the priority of TN handover to TN is higher.

[0215] In another possible implementation, the handover configuration information includes a first handover condition and a second handover condition. Optionally, it further includes a first threshold and a second threshold. The second handover condition is to handover back to the path corresponding to the access network device of the first RAT type when the signal quality between the UE and the access network device of the first RAT type is higher than the second threshold. For example, when the UE transmits a session through the access network device corresponding to the second RAT type, when the signal quality between the UE and the first access network device is higher than the second threshold, it hands over back to the path corresponding to the first access network device, that is, switches the session to the path corresponding to the first access network device for transmission. Exemplarily, the second RAT type is NTN, and the value of the second threshold set can be lower than the threshold for handover between paths of the second RAT type to the second RAT type, such as the threshold for handover between NTN to NTN, so as to avoid handover conflicts between NTN to NTN and NTN to TN, that is, the threshold for handover from NTN to TN is lower than the threshold for handover between NTN to NTN, so that the priority of handover from NTN to TN is higher.

[0216] In one possible implementation, the signal quality can be the Reference Signal Received Quality (RSRQ) or the Reference Signal Received Power (RSRP), etc.

[0217] Step 604: The UE receives the first information from the network.

[0218] The first information indicates that the network does not support the first handover method, or indicates that the UE is allowed to handover the path through the second handover method.

[0219] In one possible implementation, the information indicating that the first handover method is not supported is that the handover between the first RAT and the second RAT through the first handover method is not supported. For example, between TN and NTN (such as TN / NTN handover not supported). Or, allowing the UE to handover the path through the second handover method is the indication information allowing the UE to handover the path between the first RAT and the second RAT through the second handover method.

[0220] In one possible implementation, the area granularity corresponding to the first information can be cell / tracking area (TA) / network (PLMN) granularity. In other words, the first information is valid in the area corresponding to the area granularity. The UE is allowed to handover the path through the second handover method within this area.

[0221] In a possible implementation, the UE receives the first information through step 604a, that is, the UE receives the first information from the first access network device. For example, the first access network sends the first information to the UE through an RRC message. The RRC message may be an RRC configuration message or an RRC reconfiguration message.

[0222] In another possible implementation, the UE receives the first information through step 604b, that is, the UE receives the first information from the AMF. For example, the AMF sends the first information to the UE through a NAS message. The NAS message may be a registration acceptance message. Optionally, the AMF sends the first information to the UE only when the AMF receives the handover policy information (the handover policy information indicates that the UE is allowed to switch paths through the second handover method) from the first network element in step 602. Optionally, the AMF sends the first information to the UE only when the UE's capability information for switching paths through the second handover method is included in the registration request message.

[0223] In still another possible implementation, the UE receives the first information through a path other than the first path. It can be understood that the UE is also registered to the network through other paths at this time.

[0224] Step 605: The UE establishes a first session through the first access network device.

[0225] It can be understood that the UE transmits the data of the first session through the first path of the first access network device.

[0226] Step 606 (optional): The UE sends a registration request message to the AMF through the second access network device.

[0227] In a possible implementation, the first information triggers the UE to register to the network through the second path. For example, the UE registers to the network through the second access network device (NTN RAT), thereby reducing the time for establishing the second path. It should be noted that at this time, the UE registers to the network through the second access network device in advance and does not send data through the second access network device.

[0228] Step 607: The UE determines that the first handover condition is met.

[0229] The first handover condition is that the signal quality between the UE and the first access network device is lower than the first threshold. For example, when the TN signal quality between the UE and the first access network device is lower than the first threshold, the UE considers the TN path unavailable and thus switches to the second path. When the TN signal is higher than the first threshold, the UE considers the TN path available.

[0230] In a possible implementation, the UE locally configures the value of the first threshold. At this time, the handover configuration information received by the UE in step 603 may not include the first threshold.

[0231] Optionally, the UE also determines that the signal quality between the UE and the second access network device is higher than a third threshold. The value of the third threshold may be locally configured by the UE or received from the network.

[0232] Step 608: The UE establishes a first session through the second access network device.

[0233] When the first handover condition is satisfied, the UE switches the first path to the second path by a second handover method. That is, the UE sends a session establishment request message or a session modification request message through the second path, and the session establishment request message or the session modification request message includes a handover indication and an identifier of the first session. The handover indication is used to indicate that the first session transmitted through the first path is switched to the second path for transmission; or, the UE sends a first request through the second path, and the first request is used to request to switch the session transmitted through the first path to the second path for transmission. For example, the session is a PDU session.

[0234] Exemplarily, based on "TN / NTN handover not supported", the UE actively selects to access the cell corresponding to NTN (the cell corresponding to the NTN-corresponding frequency band), and sends a request for session handover through RAN2 corresponding to the cell.

[0235] Step 609 (optional): The UE determines that the second handover condition is satisfied.

[0236] The second handover condition is that the signal quality between the UE and the first access network device is higher than a second threshold.

[0237] In a possible implementation, the UE locally configures the value of the second threshold. At this time, the handover configuration information received by the UE in step 603 may not include the second threshold.

[0238] Step 610 (optional): The UE establishes a first session through the first access network device.

[0239] When the second handover condition is satisfied, the UE switches the second path to the first path by a second handover method. That is, the UE sends a session establishment request message or a session modification request message through the first path, and the session establishment request message or the session modification request message includes a handover indication and an identifier of the first session. The handover indication is used to indicate that the first session transmitted through the second path is switched to the first path for transmission; or, the UE sends a first request through the first path, and the first request is used to request to switch the session transmitted through the second path to the first path for transmission. For example, the session is a PDU session.

[0240] Exemplarily, according to "TN / NTN handover not supported", the UE actively selects to access the cell corresponding to TN (the cell corresponding to the TN frequency point), and sends a request for session handover through the RAN1 corresponding to the cell.

[0241] It should be noted that in this embodiment, the UE can initially access the cell corresponding to NTN (for example, there is no TN NR signal during initial access), that is, steps 605-607 can be skipped, and a session can be established through RAN2 (NTN). Subsequently, when the second handover condition in step 609 is met, the UE executes step 610 (for example, it is detected that the TN NR signal quality is higher than the second threshold). That is, in the case where the UE first accesses the cell corresponding to NTN, this embodiment can execute steps 600-604 and steps 608-610.

[0242] In method 600, the network sends information about switching the path using the second handover method to the UE, thereby realizing the control of the UE's path switching by the network. After the UE receives the information about switching the path using the second handover method, when the first handover condition is met, the UE switches the path using the second handover method, thereby avoiding conflicts between different handover processes. Further, the network sends a RAT with a higher priority to the UE, so that the UE transmits data on the path corresponding to the RAT with a higher priority as much as possible, thereby ensuring a better communication experience for the user.

[0243] As Figure 7 shown, a method 700 applicable to this application is introduced. This method can be applicable to Figure 3 the application scenario 2 described. Through method 700, the network instructs the UE to allow path switching between different PLMNs through Path Switch, so that the UE initiates a cross-PLMN path switch, thereby ensuring that the Handover process and the path conversion Path Switch cooperate without conflict. This method includes the following steps:

[0244] Step 700: The access network device and / or the AMF obtain information that the first handover method for switching the path between the first network and the second network is not supported.

[0245] In a possible implementation, the network management OAM configures the access network device and / or the AMF not to support handover between different PLMNs in the first handover manner (for example, not support Inter-PLMN handover). Among them, the access network device includes a first access network device and a second access network device, and the AMF includes AMF1 and AMF2. The first handover manner is a handover manner initiated by the radio access network device (such as handover). It can be understood that the first access network device corresponds to the first network, and the second access network device corresponds to the second network. Or the first access network device belongs to the first network, and the second access network device belongs to the second network. Or the first access network device provides access to the first network for the UE, and the second access network device provides access to the second network for the UE.

[0246] In another possible implementation, the access network device and / or the AMF locally configures information indicating that the first handover manner is not supported for handover between different PLMNs.

[0247] In a possible implementation, the access network device and / or the AMF obtains information allowing the UE to switch paths between the first network and the second network in the second handover manner. Alternatively, information indicating that the first handover manner is not supported for switching paths between the first network and the second network can indicate that the UE is allowed to switch paths between the first network and the second network in the second handover manner. Exemplarily, it indicates that the UE is allowed to switch paths between different PLMN handovers. The second handover manner is a handover manner initiated by the UE (such as path switch).

[0248] This embodiment is described by taking the first access network device and AMF1 belonging to PLMN1, the second access network device and AMF2 belonging to PLMN2, PLMN1 being the home public land mobile network (HPLMN) of the UE, and PLMN2 being the visited public land mobile network (VPLMN) of the UE as an example.

[0249] Step 701: The UE sends a registration request message to AMF1 through the first access network device.

[0250] This registration request message is used for the UE to register to the network by connecting the first access network device and AMF1. Correspondingly, AMF1 is responsible for the registration management of this UE.

[0251] It should be understood that the UE accesses the network through the first path, and the first path includes the first access network device and AMF1.

[0252] Optionally, the registration request message includes the UE's capability information for supporting path switching via the second handover method. For example, it is for supporting path switch. Or, it supports switching paths between different PLMNs via the second handover method.

[0253] Step 702 (optional): The first network element sends handover policy information to the first access network device.

[0254] The handover policy information indicates that the UE is allowed to switch paths between different PLMNs via the second handover method. Exemplarily, the handover policy information is a path switch policy.

[0255] In a possible implementation, the first network element can be a PCF or a UDM. The PCF / UDM sends the handover policy information to the first access network device via AMF1. For example, the PCF / UDM sends the handover policy information to AMF1, and AMF1 sends the handover policy information to the first access network device.

[0256] In a possible implementation, when the first network element determines, based on the UE's subscription data, that the UE is allowed to switch paths between different PLMNs via the second handover method, it sends the handover policy information to the first access network device.

[0257] In a possible implementation, the handover policy information includes indication information allowing the UE to switch paths between PLMN1 and PLMN2 via the second handover method. It can be understood that this indication information can trigger the first access network device to send handover configuration information to the UE.

[0258] In a possible implementation, the handover policy information includes the PLMN with preferred access. For example, PLMN1 is the primary access and PLMN2 is the secondary access, so that the UE preferentially accesses the cell of PLMN1.

[0259] Step 703 (optional): The first access network device sends handover configuration information to the UE.

[0260] The handover configuration information is used for the UE to switch paths between different PLMNs via the second handover method. Exemplarily, the handover configuration information is a path switch configuration.

[0261] In a possible implementation, the first access network device determines the handover configuration information based on the handover policy information. Or, the first access network device determines the handover configuration information based on the information obtained in step 700.

[0262] In a possible implementation, the first access network device broadcasts the handover configuration information. It can be understood that at this time, the first access network device does not need to receive the handover policy information according to step 702, and determines the handover configuration information according to the information obtained in step 700.

[0263] In another possible implementation, the first access network device unicasts the handover configuration information to the UE.

[0264] In a possible implementation, the handover configuration information includes a first handover condition, and optionally, a first threshold. The first handover condition is to switch the path when the signal quality between the UE and the access network device is lower than the first threshold. For example, the access network device can be an access network device of PLMN1, and the value of the set first threshold can be lower than the threshold for path switching between PLMN1 and PLMN1, so as to avoid conflicts between PLMN1 to PLMN1 handover and PLMN1 to PLMN2 handover, that is, the threshold for PLMN1 to PLMN2 handover is lower than the threshold for PLMN1 to PLMN1 handover, so that the priority of switching between different cells under PLMN1 is higher.

[0265] In another possible implementation, the handover configuration information includes a first handover condition and a second handover condition, and optionally, a first threshold and a second threshold. The second handover condition is to switch back to the path corresponding to the access network device of PLMN1 when the signal quality between the UE and the access network device of PLMN1 is higher than the second threshold. For example, when the UE transmits a session through the access network device corresponding to PLMN2, when the signal quality between the UE and the first access network device is higher than the second threshold, switch back to the path corresponding to the first access network device, that is, switch the session to the path corresponding to the first access network device for transmission. Exemplarily, the value of the set second threshold can be lower than the threshold for path switching between different cells under PLMN2 to PLMN2, so as to avoid conflicts between PLMN2 to PLMN2 handover and PLMN2 to PLMN1 handover, that is, the threshold for PLMN2 to PLMN1 handover is lower than the threshold for PLMN2 to PLMN2 handover, so that the priority of switching from PLMN2 to PLMN1 is higher.

[0266] In a possible implementation, the signal quality can be RSRQ or RSRP, etc.

[0267] Step 704: The UE receives the first information from the network.

[0268] The first information indicates that the network does not support switching paths between different PLMNs in the first handover manner, or indicates that the UE is allowed to switch paths between different PLMNs through the second handover manner.

[0269] In a possible implementation, the information indicating that the first handover method does not support handover path switching between different PLMNs is that the first handover method does not support handover path switching between PLMN1 and PLMN2. For example, the network may support the first handover method for handover path switching between PLMN1 and PLMN3, or the network may support the first handover method for handover path switching between PLMN2 and PLMN3, but the network does not support the first handover method for handover path switching between PLMN1 and PLMN2.

[0270] In a possible implementation, the area granularity corresponding to the first information may be at the Cell / Tracking Area (TA) / Public Land Mobile Network (PLMN) granularity. In other words, the first information is valid in the area corresponding to the area granularity. The UE is allowed to switch paths between different PLMNs through the second handover method within this area.

[0271] In a possible implementation, the UE receives the first information through step 704a, that is, the UE receives the first information from the first access network device. For example, the first access network sends the first information to the UE through an RRC message. The RRC message may be an RRC configuration message or an RRC reconfiguration message.

[0272] In another possible implementation, the UE receives the first information through step 704b, that is, the UE receives the first information from AMF1. For example, AMF1 sends the first information to the UE through a NAS message. The NAS message may be a registration acceptance message. Optionally, AMF sends the first information to the UE only when, in step 702, AMF receives handover policy information from the first network element (the handover policy information indicates that the UE is allowed to switch paths between different PLMNs through the second handover method). Optionally, AMF sends the first information to the UE only when the UE's capability information supporting path switching through the second handover method is included in the registration request message.

[0273] In still another possible implementation, the UE receives the first information through a path other than the first path. It can be understood that the UE is also registered to the network through other paths at this time.

[0274] Step 705: The UE establishes a first session through the first access network device.

[0275] It can be understood that the UE transmits the data of the first session through the first path of the first access network device.

[0276] It should be noted that the first path may also include a UPF. The first path in this embodiment may refer to the user plane path of the UE from the first access network device to the UPF.

[0277] Step 706 (optional): The UE sends a registration request message to AMF2 through the second access network device.

[0278] In one possible implementation, the first information triggers the UE to register with the network through the second path. For example, the UE registers with PLMN2 through a second access network device (located in PLMN2), thereby reducing the time to establish the second path. It should be noted that at this time, the UE registers with PLMN2 in advance through the second access network device and does not send data without the second access network device.

[0279] Step 707: The UE determines that the first handover condition is met.

[0280] The first handover condition is that the signal quality between the UE and the first access network device is lower than the first threshold. For example, when the PLMN signal quality between the UE and the first access network device is lower than the first threshold, the UE considers that the PLMN path is unavailable and thus switches to the second path. When the PLMN signal is higher than the first threshold, the UE considers that the PLMN path is available.

[0281] In one possible implementation, the UE locally configures the value of the first threshold. At this time, the handover configuration information received by the UE in step 703 may not include the first threshold.

[0282] Optionally, the UE also determines that the signal quality between the UE and the second access network device is higher than the third threshold. The value of the third threshold can be locally configured by the UE or received from the network.

[0283] Step 708: The UE establishes a first session through the second access network device.

[0284] When the first handover condition is met, the UE switches the first path to the second path through the second handover method. That is, the UE sends a session establishment request message or a session modification request message through the second path, and the session establishment request message or the session modification request message includes a handover indication and an identifier of the first session, and the handover indication is used to indicate that the first session transmitted through the first path is switched to the second path for transmission; or, the UE sends a first request through the second path, and the first request is used to request to switch the session transmitted through the first path to the second path for transmission. For example, this session is a PDU session.

[0285] Exemplarily, based on "Inter-PLMN handover not supported", the UE actively selects to access the cell corresponding to PLMN2 (the cell corresponding to the PLMN2-corresponding frequency band) and sends a request for session handover through RAN2 corresponding to this cell.

[0286] Step 709 (optional): The UE determines that the second handover condition is met.

[0287] The second handover condition is that the signal quality between the UE and the first access network device is higher than the second threshold.

[0288] In a possible implementation, the UE locally configures the value of the second threshold. At this time, the handover configuration information received by the UE in step 703 may not include the second threshold.

[0289] Step 710 (optional): The UE establishes a first session through the first access network device.

[0290] When the second handover condition is met, the UE switches the second path to the first path by the second handover method. That is, the UE sends a session establishment request message or a session modification request message through the first path, and the session establishment request message or the session modification request message includes a handover indication and an identifier of the first session, and the handover indication is used to indicate that the first session transmitted through the second path is switched to the first path for transmission; or, the UE sends a first request through the first path, and the first request is used to request to switch the session transmitted through the second path to the first path for transmission. For example, the session is a PDU session.

[0291] Exemplarily, the UE actively selects to access the cell corresponding to PLMN1 (the cell corresponding to the frequency point of PLMN1) according to "Inter-PLMN handover not supported", and sends a request for session handover through RAN1 corresponding to the cell.

[0292] It should be noted that in this embodiment, the UE may initially access the cell corresponding to PLMN2 (for example, there is no signal of PLMN1 during initial access), that is, steps 705-707 can be skipped, and a session is established through RAN2 (located in PLMN2). Subsequently, when the second handover condition of step 709 is met, the UE executes step 710 (for example, it is detected that the signal quality of PLMN1 is higher than the second threshold). That is, in the case where the UE first accesses the cell corresponding to PLMN2, this embodiment may execute steps 700-704 and steps 708-710.

[0293] In method 700, information for switching paths between PLMN1 and PLMN2 using the second handover method is sent to the UE through the network, thereby realizing the network's control of the UE's path switching. After the UE receives the information for switching paths by the second handover method, when the first handover condition is met, the UE switches the path by the second handover method, thereby avoiding conflicts in different handover processes. Further, a PLMN with a higher priority is sent to the UE through the network, so that the UE transmits data on the path corresponding to the PLMN with a higher priority as much as possible, thereby ensuring a better communication experience for the user.

[0294] As Figure 8 shown, a method 800 applicable to this application is introduced. This method can be applicable to Figure 2The described application scenario 1. Through method 800, the access network device instructs the UE to initiate a path switch based on the information that the UE is allowed to perform a path switch through Path Switch, thereby ensuring that the Handover process and the path conversion Path Switch are coordinated without conflict. The method includes the following steps:

[0295] Step 800 (optional): The access network device and / or the AMF obtain information indicating that the first handover method is not supported.

[0296] For relevant descriptions, refer to Figure 6 the description related to step 600 in [reference], which will not be elaborated here.

[0297] In this embodiment, the RAT type of the first access network device is TN, and the RAT type of the second access network device is NTN as an example for illustration.

[0298] Step 801: The UE sends a registration request message to the AMF through the first access network device.

[0299] The registration request message includes the UE's ability information to support switching the path through the second handover method. For example, it is to support path switch.

[0300] Step 802 (optional): The first network element sends handover policy information to the AMF.

[0301] The handover policy information indicates that the UE is allowed to switch the path through the second handover method. Exemplarily, the handover policy information is a path switch policy.

[0302] In a possible implementation, the first network element can be a PCF or a UDM. The PCF / UDM sends handover policy information to the AMF.

[0303] In a possible implementation, when the first network element determines that the UE is allowed to switch the path through the second handover method according to the UE's subscription data, it sends handover policy information to the AMF.

[0304] In another possible implementation, the AMF sends a request message to the first network element according to the UE's ability information to support switching the path through the second handover method. This request message is used to request handover policy information. In response to this request message, the first network element sends handover policy information to the AMF. Or, the AMF sends a request message to the first network element. This request message is used to request policy information, and the request message includes the UE's ability information to support switching the path through the second handover method. In response to this request message, the first network element sends handover policy information to the AMF.

[0305] In a possible implementation, the handover policy information includes indication information that allows the UE to switch paths between the first RAT and the second RAT through the second handover method. It can be understood that this indication information can trigger the AMF to send the handover policy information to the first access network device.

[0306] In a possible implementation, the handover policy information includes the RAT with priority access. For example, the TN RAT is the primary access and the NTN RAT is the secondary access, so that the UE preferentially accesses the TN cell. Or the 6G RAT is the primary access and the 5G RAT is the secondary access, so that the UE preferentially accesses the 6G cell.

[0307] Step 803: The AMF sends the handover policy information to the first access network device.

[0308] In a possible implementation, the AMF sends the handover policy information to the first access network device according to the handover policy information received from the first network element.

[0309] In another possible implementation, the AMF sends the handover policy information to the first access network device according to the information indicating non-support for the first handover method obtained in step 800.

[0310] In still another possible implementation, the AMF sends the handover policy information to the first access network device according to the UE's ability information indicating support for switching paths through the second handover method sent in step 801.

[0311] Step 804 (optional): The first access network device sends measurement configuration information to the UE.

[0312] In a possible implementation, the measurement configuration information includes the frequency signals of the cells measured by the UE. For example, the frequency corresponding to the NTN.

[0313] Step 805: The AMF sends the handover policy information to the UE through the first access network device.

[0314] In a possible implementation, the AMF sends the handover policy information to the UE through a NAS message.

[0315] For the relevant description of the handover policy information, refer to Figure 6 step 602 in, which will not be elaborated here.

[0316] Step 806: The UE establishes a first session through the first access network device.

[0317] It can be understood that the UE transmits the data of the first session through the first path of the first access network device.

[0318] It should be noted that the first path may further include a UPF. The first path in this embodiment may refer to the user plane path of the UE from the first access network device to the UPF.

[0319] Step 807 (optional): The UE sends a registration request message to the AMF via the second access network device.

[0320] In a possible implementation, the handover policy information triggers the UE to register with the network via the second path. For example, the UE registers with the network via the second access network device (NTN RAT), thereby reducing the time to establish the second path. It should be noted that at this time, the UE registers with the network in advance and does not send data.

[0321] Step 808 (optional): The AMF sends the handover policy information to the second access network device.

[0322] For the relevant description of the handover policy information, refer to Figure 6 Step 602 therein, which will not be elaborated here.

[0323] Step 809: The first access network device determines that the UE has switched to the second path through the second handover method.

[0324] In a possible implementation, the first access network device determines to switch the first path of the UE to the second path according to the handover policy information.

[0325] In a possible implementation, the first access network device determines to switch the first path of the UE to the second path according to the signal quality between the UE and the first access network device being lower than the first threshold. For example, when the TN signal quality between the UE and the first access network device is lower than the first threshold, the first access network device considers that the TN path is unavailable and thus switches the UE to the second path. When the TN signal is higher than the first threshold, the first access network device considers that the TN path is available.

[0326] In a possible implementation, the UE reports a measurement report to the first access network device according to the received measurement configuration information. The measurement report includes the Cell ID and the corresponding signal measurement value. For example, when the UE is within the satellite coverage area, the measurement report includes the Cell ID corresponding to the NTN and the signal measurement value corresponding to the Cell ID.

[0327] In a possible implementation, the first access network device determines the second access network device on the second path according to the signal quality between the UE and the second access network device being higher than the second threshold.

[0328] In another possible implementation, the first access network device first determines whether there is a cell corresponding to the TN that can be switched. If there is, it preferentially switches to the cell corresponding to the TN, that is, switches the path through the first switching method. If not, it determines to switch to the cell corresponding to the NTN, that is, switches the path through the second switching method.

[0329] In a possible implementation, when the first access network device determines that there is no cell corresponding to the TN that can be switched (for example, the signal measurement value between the UE and the first access network device is lower than the first threshold, and the measurement report of the UE is empty, or the measurement report of the UE is not received within a specific period, or the signal measurement values in the measurement report are all lower than the threshold. This can indicate that there is no suitable cell corresponding to the TN to switch to), that is, the path cannot be switched through the first switching method, and it sends a permission to switch the path through the second switching method to the UE. For example, path switch allowed. It should be noted that the first access network device can skip step 804, that is, the first access network device does not need to know the signal measurement value of the cell corresponding to the NTN measured by the UE.

[0330] Step 810: The first access network device sends handover indication information to the UE.

[0331] For example, the first access network device sends an RRC reconfiguration message to the UE, and the RRC reconfiguration message includes handover indication information. The handover indication information is used for the UE to switch the path to the second path through the second switching method. Exemplarily, the handover indication information can be a path switch indication.

[0332] Optionally, the first access network device also sends the Cell ID corresponding to the NTN to the UE, and the second radio access network device corresponding to the Cell ID is on the second path.

[0333] Optionally, the RRC reconfiguration message also includes the RAT type corresponding to the NTN.

[0334] Step 811: The UE establishes a first session through the second access network device.

[0335] The UE switches the first path to the second path through the second handover method according to the handover indication information and the Cell ID corresponding to the NTN. That is, the UE sends a session establishment request message or a session modification request message through the second radio access network device corresponding to the Cell ID. The session establishment request message or the session modification request message includes a handover indication and an identifier of the first session. The handover indication is used to indicate that the first session transmitted on the first path is switched to the second path for transmission; or, the UE sends a first request through the second path, and the first request is used to request to switch the session transmitted on the first path to the second path for transmission. For example, the session is a PDU session.

[0336] Optionally, if the first access network device does not send the Cell ID corresponding to the NTN to the UE, the UE can search for the Cell ID corresponding to the NTN and establish the first session through the second access network device corresponding to the Cell ID.

[0337] It can be understood that after step 811 is executed, the UE connects to the network and transmits session data through the second access network device.

[0338] Step 812 (optional): The second access network device determines that the UE switches to the first path through the second handover method.

[0339] In a possible implementation, the second access network device determines to switch the second path of the UE to the first path according to the handover policy information.

[0340] In a possible implementation, the second access network device determines to switch the second path of the UE to the first path according to the signal quality between the UE and the first access network device being higher than a second threshold. For example, when the TN signal quality between the UE and the first access network device is higher than the second threshold, the second access network device considers that the TN path is available, and thus switches the UE to the first path.

[0341] In a possible implementation, the UE locally configures the value of the second threshold.

[0342] In a possible implementation, the UE reports a measurement report to the second access network device, and the measurement report includes a signal measurement value corresponding to the first access network device. For example, if the UE is within the coverage of the first access network device, the measurement report includes the signal measurement value between the UE and the first access network device.

[0343] Step 813 (optional): The second access network device sends an RRC reconfiguration message to the UE.

[0344] The RRC reconfiguration message includes handover indication information. The handover indication information is used for the UE to switch the path to the first path through the second handover method. Exemplarily, the handover indication information may be a path switch indication.

[0345] Optionally, the RRC reconfiguration message further includes the Cell ID corresponding to the TN, and the first access network device corresponding to the Cell ID is on the first path.

[0346] Step 814 (optional): The UE establishes a first session through the first access network device.

[0347] The UE switches the second path to the first path through the second handover method according to the handover indication information and the Cell ID corresponding to the TN. That is, the UE sends a session establishment request message or a session modification request message through the first access network device corresponding to the Cell ID. The session establishment request message or the session modification request message includes a handover indication and an identifier of the first session. The handover indication is used to indicate that the first session transmitted on the second path is switched to the first path for transmission; or, the UE sends a first request through the first path, and the first request is used to request to switch the session transmitted on the second path to the first path for transmission. For example, the session is a PDU session.

[0348] It should be noted that in this embodiment, the UE may initially access the cell corresponding to the NTN (for example, there is no TN NR signal during initial access), that is, steps 806-810 may be skipped, and a session is established through RAN2 (NTN). Subsequently, when the second handover condition of step 812 is met, the second radio access network device executes step 813 (for example, it is detected that the TN NR signal quality is higher than the second threshold). That is, in the case where the UE first accesses the cell corresponding to the NTN, this embodiment may execute steps 800-805 and steps 811-814.

[0349] In method 800, by receiving the policy information that allows the UE to switch the path through the second handover method through the access network device, and sending the handover indication information indicating that the UE switches the path through the second handover method to the UE, the network control over the UE's path switching is realized, thereby avoiding conflicts in different handover processes. As Figure 9 shown, a method 900 applicable to this application is introduced. This method can be applicable to Figure 3 the application scenario 2 described. Through method 900, the access network device instructs the UE to initiate a path switch across PLMNs according to the UE's permission to perform path switching between different PLMNs through Path Switch, so as to ensure that the Handover process and the Path Switch of path conversion are coordinated without conflict. The method includes the following steps:

[0350] Step 900 (optional): The access network device and / or the AMF obtain information indicating that the first handover method does not support the handover path between the first network and the second network.

[0351] For related descriptions, refer to Figure 7 the description related to step 700 in , which will not be elaborated here.

[0352] In this embodiment, it is described by taking the first access network device and AMF1 belonging to PLMN1, the second access network device and AMF2 belonging to PLMN2, PLMN1 being the HPLMN of the UE, and PLMN2 being the VPLMN of the UE as an example.

[0353] Step 901: The UE sends a registration request message to AMF1 through the first access network device.

[0354] This registration request message is used for the UE to register to the network through the first path connecting the first access network device and AMF1.

[0355] The registration request message includes the UE's capability information indicating support for switching paths through the second handover method. For example, it is support for path switch. Or, support for switching paths between different PLMNs through the second handover method.

[0356] Step 902 (optional): The first network element sends handover policy information to AMF1.

[0357] The handover policy information indicates that the UE is allowed to switch paths between different PLMNs through the second handover method. Exemplarily, the handover policy information is a path switch policy.

[0358] In one possible implementation, the first network element can be a PCF or a UDM. The PCF / UDM sends handover policy information to the AMF.

[0359] In one possible implementation, when the first network element determines, based on the UE's subscription data, that the UE is allowed to switch paths between different PLMNs through the second handover method, it sends handover policy information to AMF1.

[0360] In another possible implementation, AMF1 sends a request message to the first network element based on the UE's capability information indicating support for switching paths through the second handover method. This request message is used to request handover policy information. In response to this request message, the first network element sends handover policy information to AMF1. Or, the AMF sends a request message to the first network element. This request message is used to request policy information, and the request message includes the UE's capability information indicating support for switching paths through the second handover method. In response to this request message, the first network element sends handover policy information to the AMF.

[0361] In one possible implementation, the handover policy information includes indication information allowing the UE to switch paths between PLMN1 and PLMN2 through the second handover method. It can be understood that this indication information can trigger AMF1 to send the handover policy information to the first access network device.

[0362] In one possible implementation, the handover policy information includes the PLMN to which priority access is given. For example, PLMN1 is the primary access and PLMN2 is the secondary access, so that the UE preferentially accesses the cell of PLMN1.

[0363] Step 903: AMF1 sends the handover policy information to the first access network device.

[0364] In one possible implementation, AMF1 sends the handover policy information to the first access network device according to the handover policy information received from the first network element.

[0365] In another possible implementation, AMF sends the handover policy information to the first access network device according to the information indicating non - support for the first handover method obtained in step 900.

[0366] In still another possible implementation, AMF sends the handover policy information to the first access network device according to the UE's ability information indicating support for switching paths through the second handover method sent in step 901.

[0367] Step 904 (optional): The first access network device sends measurement configuration information to the UE.

[0368] In one possible implementation, the measurement configuration information includes the frequency signals of the cells measured by the UE. For example, the frequency corresponding to the PLMN2 cell.

[0369] Step 905: AMF1 sends the handover policy information to the UE through the first access network device.

[0370] In one possible implementation, AMF1 sends the handover policy information to the UE through a NAS message.

[0371] For the relevant description of the handover policy information, refer to Figure 7 step 702 therein, which will not be elaborated here.

[0372] Step 906: The UE establishes a first session through the first access network device.

[0373] It can be understood that the UE transmits the data of the first session through the first path between the first access network device and AMF1.

[0374] It should be noted that the first path may also include a UPF. The first path in this embodiment may refer to the user plane path of the UE from the first access network device to the UPF.

[0375] Step 907 (optional): The UE sends a registration request message to the AMF2 through the second access network device.

[0376] In a possible implementation, the handover policy information triggers the UE to register with the network through the second path. For example, the UE registers with PLMN2 through the second access network device (located in PLMN2), thereby reducing the time to establish the second path. It should be noted that at this time, the UE registers with PLMN2 in advance and does not send data.

[0377] Step 908 (optional): The AMF2 sends the handover policy information to the second access network device.

[0378] For the relevant description of the handover policy information, refer to Figure 7 Step 702 in, which will not be elaborated here.

[0379] Step 909: The first access network device determines that the UE has switched to the second path through the second handover method.

[0380] In a possible implementation, the first access network device determines to switch the first path of the UE to the second path according to the handover policy information.

[0381] In a possible implementation, the first access network device determines to switch the first path of the UE to the second path according to the signal quality between the UE and the first access network device being lower than the first threshold. For example, when the signal quality of PLMN1 between the UE and the first access network device is lower than the first threshold, the first access network device considers that the PLMN1 path is unavailable, and thus switches the UE to the second path. When the signal of PLMN1 is higher than the first threshold, the first access network device considers that the PLMN1 path is available.

[0382] In a possible implementation, the UE reports a measurement report to the first access network device according to the received measurement configuration information. The measurement report includes the Cell ID and the corresponding signal measurement value. For example, if the UE is within the coverage area of PLMN2, the measurement report includes the Cell ID corresponding to PLMN2 and the signal measurement value corresponding to the Cell ID.

[0383] In a possible implementation, the first access network device determines the second access network device on the second path according to the signal quality between the UE and the second access network device being higher than the second threshold.

[0384] In another possible implementation, the first access network device first determines whether there is a cell corresponding to PLMN1 that can be switched. If so, it preferentially switches to the cell corresponding to PLMN1, that is, switches the path through the first switching method. If not, it determines to switch to the cell corresponding to PLMN2, that is, switches the path through the second switching method.

[0385] In a possible implementation, when the first access network device determines that there is no cell corresponding to PLMN1 that can be switched (for example, the signal measurement value between the UE and the first access network device is lower than the first threshold, and the measurement report of the UE is empty, or the measurement report of the UE is not received within a specific period, or the signal measurement values in the measurement report are all lower than the threshold. This can indicate that there is no suitable cell corresponding to PLMN1 to switch to), that is, the path cannot be switched through the first switching method, and it sends a message allowing the UE to switch the path through the second switching method to the UE. For example, it allows a path switch (path switch allowed). It should be noted that the first access network device can skip step 904, that is, the first access network device does not need to know the signal measurement value of the cell corresponding to PLMN2 measured by the UE.

[0386] Step 910: The first access network device sends an RRC reconfiguration message to the UE.

[0387] The RRC reconfiguration message includes handover indication information. The handover indication information is used for the UE to switch the path to the second path through the second switching method. Exemplarily, the handover indication information can be a path switch indication (path switchindication).

[0388] Optionally, the RRC reconfiguration message further includes the Cell ID corresponding to PLMN2, and the second radio access network device corresponding to this Cell ID is on the second path.

[0389] Optionally, the RRC reconfiguration message further includes the identifier of PLMN2.

[0390] Step 911: The UE establishes a first session through the second access network device.

[0391] The UE switches the first path to the second path through the second switching method according to the handover indication information and the Cell ID corresponding to PLMN2. That is, the UE sends a session establishment request message or a session modification request message through the second radio access network device corresponding to this Cell ID. The session establishment request message or the session modification request message includes a handover indication and an identifier of the first session. The handover indication is used to indicate that the first session transmitted on the first path is switched to the second path for transmission; or, the UE sends a first request through the second path, and the first request is used to request that the session transmitted on the first path be switched to the second path for transmission. For example, this session is a PDU session.

[0392] Optionally, if the first access network device does not send the Cell ID corresponding to PLMN2 to the UE, the UE may search for the Cell ID corresponding to PLMN2 and establish a first session through the second access network device corresponding to the Cell ID.

[0393] It can be understood that after step 911 is executed, the UE connects to PLMN2 through the second access network device and transmits session data.

[0394] Step 912 (optional): The second access network device determines that the UE switches to the first path through the second handover method.

[0395] In a possible implementation, the second access network device determines to switch the second path of the UE to the first path according to the handover policy information.

[0396] In a possible implementation, the second access network device determines to switch the second path of the UE to the first path according to that the signal quality between the UE and the first access network device is higher than a second threshold. For example, when the TN signal quality between the UE and the first access network device is higher than the second threshold, the second access network device considers that the TN path is available, and thus switches the UE to the first path.

[0397] In a possible implementation, the UE locally configures the value of the second threshold.

[0398] In a possible implementation, the UE reports a measurement report to the second access network device, and the measurement report includes the signal measurement value corresponding to the first access network device. For example, if the UE is within the coverage of the first access network device, the measurement report includes the signal measurement value between the UE and the first access network device.

[0399] Step 913 (optional): The second access network device sends an RRC reconfiguration message to the UE.

[0400] The RRC reconfiguration message includes handover indication information. The handover indication information is used for the UE to switch the path to the first path through the second handover method. Exemplarily, the handover indication information may be a path switch indication.

[0401] Optionally, the RRC reconfiguration message further includes the Cell ID corresponding to PLMN1, and the first access network device corresponding to the Cell ID is on the first path.

[0402] Step 914 (optional): The UE establishes a first session through the first access network device.

[0403] The UE switches the second path to the first path through the second handover method according to the handover indication information and the Cell ID corresponding to PLMN1. That is, the UE sends a session establishment request message or a session modification request message through the first access network device corresponding to the Cell ID. The session establishment request message or the session modification request message includes a handover indication and an identifier of the first session. The handover indication is used to indicate that the first session transmitted on the second path is switched to the first path for transmission; alternatively, the UE sends a first request through the first path, and the first request is used to request to switch the session transmitted on the second path to the first path for transmission. For example, the session is a PDU session.

[0404] It should be noted that in this embodiment, the UE may initially access a cell corresponding to PLMN2 (for example, there is no signal of PLMN1 during initial access), that is, steps 906-910 may be skipped, and a session may be established through RAN2 (belonging to PLMN2). Subsequently, when the second handover condition in step 912 is met, the second radio access network device executes step 913 (for example, it is detected that the signal quality of the cell corresponding to PLMN1 is higher than the second threshold). That is, in the case where the UE first accesses a cell corresponding to PLMN2, this embodiment may execute steps 900-905, and steps

[0405] In method 900, the access network device receives policy information that allows the UE to switch paths between different PLMNs through the second handover method, and sends handover indication information indicating that the UE switches paths through the second handover method, so as to implement network control over the terminal's path switching, and further avoid conflicts in different handover processes.

[0406] As described above in conjunction with Figures 6 to 9 , the method-side embodiments of the present application have been described in detail. Next, the apparatus-side embodiments of the present application will be described in detail in conjunction with Figures 10 to 12 . It should be understood that the descriptions of the apparatus embodiments correspond to the descriptions of the method embodiments. Therefore, parts not described in detail can be referred to the previous method embodiments.

[0407] Figure 10 is a schematic structural diagram of a communication apparatus 1000 provided by an embodiment of the present application. As Figure 10 shown, the apparatus 1000 may include a transceiver unit 1010 and a processing unit 1020. The transceiver unit 1010 can communicate with the outside, and the processing unit 1020 is used for data processing. The transceiver unit 1010 may also be referred to as a communication interface or a transceiver unit.

[0408] In a possible design, the apparatus 1000 can implement the steps or processes corresponding to those performed by the UE in the above method embodiments. Among them, the processing unit 1020 is configured to perform the operations related to the processing of the UE in the above method embodiments, and the transceiver unit 1010 is configured to perform the operations related to the transceiver of the UE in the above method embodiments.

[0409] In another possible design, the apparatus 1000 can implement the steps or processes corresponding to those performed by the access and mobility management network element in the above method embodiments. Among them, the transceiver unit 1010 is configured to perform the operations related to the transceiver of the access and mobility management network element in the above method embodiments, and the processing unit 1020 is configured to perform the operations related to the processing of the access and mobility management network element in the above method embodiments.

[0410] In still another possible design, the apparatus 1000 can implement the steps or processes corresponding to those performed by the access network device in the above method embodiments. Among them, the processing unit 1020 is configured to perform the operations related to the processing of the access network device in the above method embodiments, and the transceiver unit 1010 is configured to perform the operations related to the transceiver of the access network device in the above method embodiments.

[0411] It should be understood that the apparatus 1000 is embodied in the form of functional units here. The term "unit" here may refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a dedicated processor or a group of processors, etc.) for executing one or more software or firmware programs, and a memory, a combined logic circuit and / or other suitable components supporting the described functions. In an alternative example, those skilled in the art can understand that the apparatus 1000 may specifically be the sending end in the above embodiments and can be used to execute the respective processes and / or steps corresponding to the sending end in the above method embodiments. Or, the apparatus 2000 may specifically be the receiving end in the above embodiments and can be used to execute the respective processes and / or steps corresponding to the receiving end in the above method embodiments. To avoid repetition, details are not described herein again.

[0412] The apparatus 1000 in each of the above solutions has the function of implementing the corresponding steps executed by the sending end in the above method, or the apparatus 1000 in each of the above solutions has the function of implementing the corresponding steps executed by the receiving end in the above method. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions; for example, the transceiver unit can be replaced by a transceiver (for example, the sending unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiver), and other units, such as the processing unit, can be replaced by a processor to respectively execute the transceiver operations and related processing operations in each method embodiment.

[0413] In addition, the above transceiver unit can also be a transceiver circuit (for example, it can include a receiving circuit and a sending circuit), and the processing unit can be a processing circuit. In the embodiments of the present application, the apparatus 1000 can be the receiving end or the sending end in the foregoing embodiments, or can be a chip or a chip system, for example: a system on chip (SoC). Among them, the transceiver unit can be an input / output circuit or a communication interface. The processing unit is a processor or a microprocessor or an integrated circuit integrated on the chip. This is not limited herein.

[0414] Figure 11 It is a schematic structural diagram of a communication apparatus 2000 provided by an embodiment of the present application. As Figure 11 shown, the apparatus 2000 includes a processor 2010 and a transceiver 2020. Among them, the processor 2010 and the transceiver 2020 communicate with each other through an internal connection path, and the processor 2010 is used to execute instructions to control the transceiver 2020 to send signals and / or receive signals.

[0415] Optionally, the apparatus 2000 may further include a memory 2030, and the memory 2030 communicates with the processor 2010 and the transceiver 2020 through an internal connection path. The memory 2030 is used to store instructions, and the processor 2010 can execute the instructions stored in the memory 2030.

[0416] In a possible implementation manner, the apparatus 2000 is used to implement each process and step corresponding to the UE in the above method embodiments.

[0417] In another possible implementation manner, the apparatus 2000 is used to implement each process and step corresponding to the access and mobility management network element in the above method embodiments.

[0418] In still another possible implementation manner, the apparatus 2000 is used to implement each process and step corresponding to the access network device in the above method embodiments.

[0419] It should be understood that the device 2000 may specifically be the sending end or the receiving end in the above embodiments, or may be a chip or a chip system. Correspondingly, the transceiver 2020 may be the transceiver circuit of the chip, which is not limited herein. Specifically, the device 2000 may be used to execute each step and / or process corresponding to the sending end or the receiving end in the above method embodiments.

[0420] Optionally, the memory 2030 may include a read-only memory and a random access memory, and provide instructions and data to the processor. A part of the memory may further include a non-volatile random access memory. For example, the memory may also store information about the device type. The processor 2010 may be used to execute the instructions stored in the memory, and when the processor 2010 executes the instructions stored in the memory, the processor 2010 is used to execute each step and / or process of the above method embodiments corresponding to the sending end or the receiving end.

[0421] In the implementation process, each step of the above method may be completed by the integrated logic circuit of the hardware in the processor or the instructions in the form of software. The steps of the method disclosed in combination with the embodiments of the present application may be directly embodied as being executed by the hardware processor, or executed by a combination of the hardware and software modules in the processor. The software module may be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and combines its hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0422] It should be noted that the processor in the embodiments of the present application may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method embodiments may be completed by the integrated logic circuit of the hardware in the processor or the instructions in the form of software. The above processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The processor in the embodiments of the present application may implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of the present application may be directly embodied as being executed by the hardware decoding processor, or executed by a combination of the hardware and software modules in the decoding processor. The software module may be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and combines its hardware to complete the steps of the above method.

[0423] It can be understood that the memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory, dynamic random access memory, synchronous dynamic random access memory, double data rate synchronous dynamic random access memory, enhanced synchronous dynamic random access memory, synchronous link dynamic random access memory, and direct memory bus random access memory. It should be noted that the memory of the systems and methods described herein is intended to include but not be limited to these and any other suitable types of memory.

[0424] Figure 12 is a schematic structural diagram of a chip system 3000 provided by an embodiment of the present application. As Figure 12 shown, the chip system 3000 (or can also be referred to as a processing system) includes a logic circuit 3010 and an input / output interface 3020.

[0425] Among them, the logic circuit 3010 can be the processing circuit in the chip system 3000. The logic circuit 3010 can be coupled to a storage unit and call the instructions in the storage unit, so that the chip system 3000 can implement the methods and functions of the embodiments of the present application. The input / output interface 3020 can be the input / output circuit in the chip system 3000, output the information processed by the chip system 3000, or input the data or signaling information to be processed into the chip system 3000 for processing.

[0426] As a solution, the chip system 3000 is used to implement the operations performed by the UE in the above method embodiments.

[0427] As a solution, the chip system 3000 is used to implement the operations performed by the access and mobility management network element in the above method embodiments.

[0428] As a solution, the chip system 3000 is used to implement the operations performed by the access network device in the above method embodiments.

[0429] The embodiments of the present application further provide a computer-readable storage medium, on which computer instructions for implementing the methods executed by the UE, the access and mobility management network element, and the access network device in the above method embodiments are stored.

[0430] The embodiments of the present application further provide a computer program product, including computer program code or instructions. When the computer program code or instructions run on a computer, the computer is enabled to implement the methods executed by the UE, the access and mobility management network element, and the access network device in the above method embodiments.

[0431] The embodiments of the present application further provide a communication system, including the aforementioned UE, access and mobility management network element, and access network device. Optionally, it may further include a UDM or a PCF.

[0432] For the explanations and beneficial effects of the relevant content in any of the above-mentioned devices, reference can be made to the corresponding method embodiments provided above, and details are not elaborated here.

[0433] To facilitate the understanding of the above embodiments provided by the present application, the following points are noted:

[0434] 1) In the present application, if there is no special explanation and logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0435] 2) In the present application, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects and indicates that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. In the text description of the present application, the character " / " generally represents an "or" relationship between the preceding and following associated objects. "At least one (item)" or its similar expression refers to any combination of these items, including any combination of single item (item) or plural items (items). For example, at least one (item) of a, b, and c can represent: a, or, b, or, c, or, a and b, or, a and c, or, b and c, or, a, b, and c. Where a, b, and c can be single or multiple respectively.

[0436] 3) In the present application, "first", "second", and various numerical numbers (such as #1, #2, etc.) are used for distinction for the convenience of description and do not limit the scope of the embodiments of the present application. For example, to distinguish different messages, etc., rather than for describing a specific order or sequence. It should be understood that the objects described in this way can be interchanged under appropriate circumstances so as to be able to describe the solutions other than the embodiments of the present application.

[0437] 4) In this application, descriptions such as "when...", "in the case of...", and "if" all refer to the device making corresponding processing under certain objective circumstances, not limited to time, and do not require the device to have a judgment action when implemented, nor does it mean there are other limitations.

[0438] 5) In this application, "for indicating" can include direct indication and indirect indication. When describing that a certain indication information is used to indicate A, it can include that the indication information directly indicates A or indirectly indicates A, rather than necessarily carrying A in the indication information.

[0439] The indication methods involved in the embodiments of this application should be understood to cover various methods that can enable the party to be indicated to obtain the indication information. The indication information can be sent as a whole, or divided into multiple sub-information and sent separately, and the sending periods and / or sending times of these sub-information can be the same or different. This application does not limit the specific sending method.

[0440] The "indication information" in the embodiments of this application can be explicit indication, that is, directly indicated by signaling, or obtained according to the parameters indicated by signaling, combined with other rules or other parameters or through derivation. It can also be implicit indication, that is, obtained according to rules or relationships, or other parameters, or through derivation. This application does not make specific limitations on this.

[0441] 6) In this application, "protocol" can refer to standard protocols in the communication field. For example, it can include 5G protocols, NR protocols, and related protocols applied to future communication systems. This application does not make limitations on this. "Pre-defined" can include pre-definition. For example, protocol definition. "Pre-configuration" can be implemented by pre-saving corresponding codes, tables, or other ways that can be used to indicate relevant information in the device. This application does not limit its specific implementation method.

[0442] 7) In this application, "communication" can also be described as "data transmission", "information transmission", "data processing", etc. "Transmission" includes "sending" and "receiving".

[0443] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this article can be implemented by electronic hardware, or by a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0444] Those skilled in the art can 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 foregoing method embodiments and will not be elaborated herein.

[0445] In several embodiments provided in the present 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 illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, 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 displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0446] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0447] In addition, in each embodiment of the present application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0448] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art or a part of this technical solution can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to enable a computer device to execute all or part of the steps of the methods described in each embodiment of the present application. The foregoing storage medium includes: USB flash drives, mobile hard disks, read-only memories, random access memories, magnetic disks, or optical disks and other various media that can store program codes.

[0449] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application and should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A communication method, characterized in that, The method includes: The terminal receives first information from the network, where the first information indicates that the network does not support a first handover method, or indicates that the terminal is allowed to switch paths through a second handover method; the first handover method is a handover method initiated by a radio access network device, and the second handover method is a handover method initiated by the terminal. According to the first information, switch the first path to a second path through the second handover method; the first path includes the connection between the terminal and a first access network device, and the second path includes the connection between the terminal and a second access network device.

2. The method according to claim 1, wherein The step of switching the first path to the second path according to the first information through the second handover method includes: The terminal sends a session establishment request message or a session modification request message through the second path, where the session establishment request message or the session modification request message includes a handover indication and an identifier of a first session, and the handover indication is used to indicate that the first session transmitted on the first path is switched to be transmitted on the second path; or The terminal sends a first request through the second path, and the first request is used to request to switch the session transmitted on the first path to be transmitted on the second path.

3. The method according to claim 1 or 2, characterized in that Before switching the first path to the second path through the second handover method, the method further includes: When a first handover condition is satisfied, switch the first path to the second path through the second handover method; the first handover condition is that the signal quality between the terminal and the first access network device is lower than a first threshold.

4. The method according to any one of claims 1 to 3, characterized in that The radio access technology (RAT) corresponding to the first access network device is a first RAT, and the RAT corresponding to the second access network device is a second RAT. The first information indicating that the network does not support the first handover method, or indicating that the terminal is allowed to switch paths through the second handover method includes: The first information indicates that the network does not support handover between the first RAT and the second RAT through the first handover method, or indicates that the terminal is allowed to perform handover between the first RAT and the second RAT through the second handover method.

5. The method according to any one of claims 1-4, characterized in that, The first information includes policy information, and the policy information indicates preferential access to the access network device corresponding to the first RAT type. The method further includes: Switch the second path to the first path through the second handover method, where the first path includes the connection between the terminal and the first access network device, and the RAT corresponding to the first access network device is the first RAT.

6. The method according to claim 5, wherein The step of switching the second path to the first path through the second handover method includes: When a second handover condition is satisfied, switch the second path to the first path through the second handover method; the second handover condition is that the signal quality between the terminal and the access network device corresponding to the first RAT type is higher than a second threshold.

7. A communication method, characterized in that, The method includes: Send a first message to the terminal, where the first message indicates that the network does not support a first handover method, or indicates that the terminal is allowed to switch paths through a second handover method; the first handover method is a handover method initiated by a radio access network device, and the second handover method is a handover method initiated by the terminal; Receive a first request sent by the terminal through a second path, where the first request is used to request to switch a session transmitted through a first path to be transmitted through the second path; the first path includes the connection between the terminal and a first access network device, and the second path includes the connection between the terminal and a second access network device.

8. The method according to claim 7, wherein Before sending the first message to the terminal, the method further includes: Determine the first message according to the configuration of the network management; or Receive the first message sent by a policy control network element or a data management network element.

9. The method according to claim 7 or 8, characterized in that, The first request is a session establishment request message or a session modification request message, and the session establishment request message or the session modification request message includes a handover indication and an identifier of a first session, and the handover indication is used to indicate to switch the first session transmitted through the first path to be transmitted through the second path.

10. A communication method, characterized in that, The method includes: Receive handover policy information, where the handover policy information indicates that the terminal is allowed to switch paths through a second handover method, and the second handover method is a handover method initiated by the terminal; Send handover configuration information to the terminal according to the handover policy information, where the handover configuration information is used for the terminal to switch paths through the second handover method.

11. The method according to claim 10, characterized in that, The handover configuration information includes a first handover condition, and the first handover condition is used for the terminal to switch paths through the second handover method when the signal quality between the terminal and the access network device is lower than a first threshold.

12. The method according to claim 11, wherein The handover configuration information further includes a second handover condition, and the second handover condition is used for the terminal to switch back to the path corresponding to the access network device when the signal quality between the terminal and the corresponding access network device is higher than a second threshold.

13. The method according to any one of claims 10 to 12, characterized in that The method further includes: Send a first message to the terminal, where the first message indicates that the network does not support a first handover method, and the first handover method is a handover method initiated by a radio access network device.

14. The method according to claim 13, wherein The method further includes: Determine the first message according to the configuration of the network management; or Receive the first message sent by an access and mobility management network element.

15. A communication method, characterized in that, The method includes: Receive handover policy information, where the handover policy information indicates that the terminal is allowed to switch paths through a second handover method, and the second handover method is a handover method initiated by the terminal; According to the handover policy information, send path handover indication information to the terminal, where the path handover indication information is used for the terminal to switch paths through the second handover method, the first path includes the connection between the terminal and a first access network device, and the second path includes the connection between the terminal and a second access network device.

16. The method according to claim 15, characterized in that, Sending path handover indication information to the terminal according to the handover policy information includes: Determine to switch the first path of the terminal to the second path according to the handover policy information; Send the path handover indication information to the terminal.

17. The method according to claim 15 or 16, characterized in that, Before determining to switch the first path of the terminal to the second path according to the handover policy information, the method further includes: Receiving a measurement report sent by the terminal, where the measurement report includes the signal quality of a first cell corresponding to the first access network device, and the signal quality of the first cell is lower than a first threshold corresponding to the second path switching method.

18. The method according to any one of claims 15-17, characterized in that, Before sending handover indication information to the terminal, the method further includes: Determining handover indication information according to first information, where the first information indicates that the network does not support a first handover method, and the first handover method is a handover method initiated by a radio access network device.

19. The method according to claim 18, wherein The method further includes: Determining the first information according to the configuration of the network management; or, Receiving the first information sent by an access and mobility management network element.

20. A communication method, characterized in that, The method includes: Receiving path switching indication information through the first access network device; The terminal, according to the path switching indication information, switches the first path to the second path through a second handover method; the second handover method is a handover method initiated by the terminal, the first path includes the connection between the terminal and the first access network device, and the second path includes the connection between the terminal and the second access network device.

21. The method according to claim 20, wherein, Before receiving the path switching indication information through the first access network device, the method further includes: The terminal sending capability information, where the capability information indicates that the terminal supports switching paths through the second handover method.

22. The method according to claim 20 or 21, characterized in that, The method further includes: Sending a measurement report to the first access network device, where the measurement report includes the signal quality of a first cell corresponding to the first access network device, a second cell identifier, and the corresponding signal quality; Receiving the second cell identifier and switching to the second cell of the second path according to the second cell identifier.

23. A terminal, characterized in that, The terminal includes a module for executing the communication method according to any one of claims 1-6, or includes a module for executing the communication method according to any one of claims 20-22.

24. An access and mobility management network element, characterized in that, The access and mobility management network element includes a module for executing the communication method according to any one of claims 7-9.

25. An access network device, characterized in that, The access network device includes a module for executing the communication method according to any one of claims 10-19.

26. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a computer program or instruction, and when the computer program or instruction runs on a computer, the computer is caused to execute the communication method according to any one of claims 1-22.

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