Communication method, system and device

Abstract

The invention discloses a communication method, system and device. According to the technical scheme provided by the invention, a first access network device sends a switching request message about a terminal to a second access network device based on first switching time information, wherein the first switching time information comprises time corresponding to at least one access network device serving the terminal; and after receiving the switching request message, the second access network equipment communicates with the user plane function network element based on the switching request message and the core network tunnel information of the terminal stored in the second access network equipment. Therefore, signaling interaction related to the core network tunnel information between the second access network equipment and the core network equipment is reduced, and the switching efficiency of executing the switching process by the terminal is improved.

Description

Technical Field

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

[0002] In the scenario where the satellite communication mode is the regeneration transmission mode, the base station or part of the base station functions are deployed on the satellite, and the satellites can complete the signaling interaction and user data transmission between the base stations.

[0003] Generally, even if the user equipment (UE) does not move, as the satellite flies, the coverage (or signal strength, etc.) of the wireless signal provided by the radio access network (RAN) deployed on the satellite changes, which will trigger the switching process of the UE, that is, the UE switches from accessing the source access network device to accessing the target access network device. However, the number of UEs served by the core network is large, and the low-orbit satellite moves quickly. Each UE will switch to a different target access network device more frequently, resulting in frequent transmission of UE information between the access network device and the core network device. How to improve the switching efficiency has become an urgent problem to be solved in this scenario. Summary of the invention

[0004] The present application provides a communication method, system and device to improve the switching efficiency problem of a terminal frequently triggering a switching process.

[0005] In a first aspect, the present application provides a communication method, which is applied to a second access network device, and the method includes: receiving a switching request message from a first access network device, the switching request message being used to request switching a terminal to the second access network device; and communicating with a user plane functional network element based on the switching request message and the core network tunnel information of the terminal stored in the second access network device.

[0006] In an embodiment of the present application, after the second access network device receives the switching request message of the terminal, it communicates with the UPF based on the core network tunnel information of the terminal stored in the second access network device, thereby reducing the signaling interaction between the second access network device and the core network device regarding the core network tunnel information, such as omitting the process of the second access network device requesting and waiting for the UPF to allocate core network tunnel information to the terminal in the switching process, thereby improving the switching efficiency of the terminal that frequently executes the switching process.

[0007] In a possible implementation manner, before receiving the switching request message from the first access network device, the method further includes: receiving core network tunnel information of the terminal, and storing the core network tunnel information.

[0008] In a possible implementation, the receiving of the core network tunnel information of the terminal includes: receiving the core network tunnel information of the terminal from the first access network device, the core network tunnel information of the terminal is the core network tunnel information that the first access network device requests the user plane functional network element to allocate to the terminal, the core network tunnel information is used to establish a tunnel between the second access network device and the user plane functional network element, and the tunnel is used to carry data of the terminal. Alternatively, the receiving of the core network tunnel information of the terminal includes: receiving the core network tunnel information of the terminal from the session management functional network element, the core network tunnel information of the terminal is the core network tunnel information that the user plane functional network element allocated for the tunnel between the second access network device and the user plane functional network element when the terminal previously accessed the second access network device.

[0009] In a possible implementation, after receiving the switching request message from the first access network device, the method further includes: if the second access network device does not store the core network tunnel information of the terminal, or the second access network device does not allocate access network tunnel information to the terminal, then sending a path switching message to the access and mobility management function network element, and the path switching message is used to switch the path corresponding to the terminal.

[0010] Exemplarily, the path corresponding to the switching terminal may be to switch the tunnel of the GPRS user plane part (userplane part of GTP, GTP-U) of the terminal session from the first access network device to the user plane function network element (UPF) to the tunnel from the second access network device to the UPF, where the UPF corresponding to the first access network device and the UPF corresponding to the second access network device may be the same or different, and this document does not limit this.

[0011] Specifically, the path switching message can be used to trigger the access and mobility management function network element (AMF) to request the UPF to allocate core network tunnel information to the terminal through the session management network element (SMF), and the core network tunnel information is used to establish a tunnel between the second access network device and the user plane function network element for carrying the data of the terminal. In some other possible implementations, the path switching message carries the terminal identifier assigned to the terminal by the second access network device. The path switching message is also used to trigger the AMF to update the second identifier of the terminal. The second identifier is a private terminal identifier allocated to the terminal by the access network device to which the terminal is currently connected and stored in the AMF, which is used to identify the terminal between the AMF and the access network device.

[0012] In a possible implementation, after receiving the switching request message from the first access network device, the method further includes: if the second access network device has stored the core network tunnel information of the terminal, and the second access network device has allocated the access network tunnel information to the terminal, then a path switching message is not sent to the access and mobility management function network element, and the path switching message is used to switch the path corresponding to the terminal.

[0013] In a possible implementation manner, the method further includes: allocating the access network tunnel information to the terminal; and sending the access network tunnel information to an access and mobility management function network element.

[0014] In an embodiment of the present application, the second access network device can send access network tunnel information allocated by the second access network device to the terminal to the AMF when the second access network device is in a connected state or an idle state with the terminal. The second access network device and the terminal are in a connected state means that the terminal is connected to the second access network device, and the second access network device and the terminal are in an idle state means that the terminal is not connected to the terminal.

[0015] In a possible implementation, before receiving the switching request message from the first access network device, the method also includes: receiving a first request, the first request being used to request allocation of access network tunnel information for the terminal; based on the first request, allocating access network tunnel information to the terminal; and sending a first response, the first response carrying the access network tunnel information.

[0016] In a possible implementation manner, the first response further carries an identifier of the second access network device.

[0017] In a possible implementation manner, the first request includes identification information of a first session of the terminal, and the first request is specifically used to request allocation of access network tunnel information for the first session.

[0018] In one possible implementation, the first request comes from the first access network device, and sending the first response includes: sending the first response to the first access network device, the first response carrying the access network tunnel information and first indication information, the first indication information being used to instruct the first access network device to send the access network tunnel information to the access and mobility management function network element.

[0019] In a possible implementation manner, the first request comes from the access and mobility management function network element, and the sending the first response includes: sending the first response to the access and mobility management function network element.

[0020] In a possible implementation manner, the core network tunnel information corresponds to a first session of the terminal.

[0021] In a possible implementation, before receiving the switching request message from the first access network device, the method also includes: receiving a second request from the first access network device, the second request being used to request the second access network device to assign a terminal identifier to the terminal; based on the second request, assigning a terminal identifier to the terminal; and sending a second response to the first access network device, the second response carrying the terminal identifier.

[0022] In a possible implementation manner, the second response further carries second indication information, where the second indication information is used to instruct the first access network device to send the terminal identifier to the access and mobility management function network element.

[0023] In one possible implementation, the terminal is a stationary terminal. Exemplarily, it can be determined whether the UE is stationary or mobile based on the expectedUE behavior in the contract information of the terminal. Alternatively, it can be determined whether the UE is a stationary terminal based on the location information of the UE over a period of time. In one possible implementation, after receiving the switching request message, the second access network device determines whether the terminal is a stationary terminal, and when it is determined that the terminal is a stationary terminal, communicates with the UPF based on the core network tunnel information stored in the second access network device.

[0024] In a possible implementation, after receiving the switching request message from the first access network device, the method further includes: receiving first access network tunnel information from a session management network element, where the first access network tunnel information is allocated by the session management network element for establishing a tunnel for the terminal between the second access network device and the UPF.

[0025] In a second aspect, the present application provides a communication method, which is applied to a first access network device, and the method includes: based on first switching time information of the terminal, determining to switch the terminal to a second access network device, the first switching time information including the time when at least one access network device serves the terminal, and the at least one access network device includes the second access network device; sending a switching request message to the second access network device, the switching request message being used to request to switch the terminal to the second access network device.

[0026] In an embodiment of the present application, the first switching time information stored in the first access network device and the second switching time information stored in the AMF both include the time when the access network device serves the terminal, and the first switching time information and the second switching time information correspond to each other within a certain error range.

[0027] Using the communication method provided in the present application, the first access network device initiates a switching request to the second access network device based on the first switching time information, and the AMF switches the terminal to the second access network device based on the second switching time information. That is, the air interface switching of the terminal between the first access network device and the second access network device and the update of the tunnel information of the terminal on the core network side are synchronized based on the switching time information. The first access network device or the second access network device does not need to send a synchronization message (such as a path switching message) to the AMF about switching the terminal to the second access network device, thereby reducing the signaling interaction about the terminal information between the access network device and the core network device, thereby improving the switching efficiency while ensuring the consistency and integrity of the terminal switching process.

[0028] In a possible implementation, the method also includes: determining the first switching time information based on the access time of the terminal to the at least one access network device respectively during the satellite operation cycle; or, determining the first switching time information based on the position and ephemeris information of the terminal; or, receiving the first switching time information from an access and mobility management function network element.

[0029] In one possible implementation, the satellite corresponding to the at least one access network device and the satellite corresponding to the first access network device belong to the same constellation; or, the satellite corresponding to the at least one access network device and the satellite corresponding to the first access network device have a direct and / or indirect inter-satellite link connection; or, the coverage range of each of the at least one access network device includes the location of the terminal.

[0030] The coverage range of each of the at least one access network device may refer to all ranges covered by the signal of each access network device when the access network device moves along the running trajectory. Accordingly, the coverage range of each of the at least one access network device including the location of the terminal may refer to all ranges covered by the signal of each access network device including the location of the terminal.

[0031] In a possible implementation, before sending a switching request message to the second access network device, the method also includes: requesting the second access network device to allocate access network tunnel information for the terminal; receiving access network tunnel information from the second access network device; and sending the access network tunnel information to an access and mobility management function network element.

[0032] In an embodiment of the present application, the first access network device can forward the access network tunnel information allocated to the terminal by other access network devices (the other access network devices include the second access network device) to the AMF. For example, the other access network devices can be all or part of the access network devices that can serve the terminal except the first access network device, which is equivalent to the signaling interaction of sending the access network tunnel information of all the access network devices (or the part of the access network devices) to the AMF, and merging them into the same message for sending. When the terminal accesses the corresponding access network device for the first time or subsequently, it does not need to send the path switching message carrying the access network tunnel information to the AMF through the NG interface, thereby alleviating the communication pressure of the NG interface and further improving the switching efficiency.

[0033] In a possible implementation manner, the requesting the second access network device to allocate access network tunnel information for the terminal includes: requesting the second access network device to allocate access network tunnel information for a first session of the terminal.

[0034] In a possible implementation, the requesting the second access network device to allocate access network tunnel information for the first session of the terminal includes: during the process of the terminal establishing the first session through the first access network device, requesting the second access network device to allocate access network tunnel information for the first session.

[0035] In a possible implementation, before sending a switching request message to the second access network device, the method also includes: requesting other access network devices to allocate a terminal identifier for the terminal, the other access network devices including one or more access network devices among the at least one access network device except the first access network device; receiving the terminal identifier allocated to the terminal by the other access network devices; and sending the terminal identifier allocated to the terminal by the other access network devices to the access and mobility management function network element.

[0036] In a possible implementation, the requesting the at least one access network device to allocate a terminal identifier for the terminal includes: during the process of establishing a first session by the terminal through the first access network device, requesting the at least one access network device to allocate a terminal identifier for the terminal.

[0037] In an embodiment of the present application, the first access network device can forward the terminal identifier assigned to the terminal by other access network devices (the other access network devices include the second access network device) to the AMF. For example, the other access network devices are all or part of the access network devices that can serve the terminal except the first access network device. This is equivalent to sending the signaling interaction of the terminal identifier of all access network devices (or the part of the access network devices) to the AMF, and merging them into the same message and sending them. When the terminal accesses the corresponding access network device for the first time or subsequently, it does not need to send a path switching message carrying the terminal identifier to the AMF through the NG interface, thereby further alleviating the communication pressure of the NG interface and improving the switching efficiency.

[0038] In a possible implementation, before sending a switching request message to the second access network device, the method also includes: requesting the user plane function network element to allocate core network tunnel information for the terminal; receiving first core network tunnel information from the user plane function network element, the first core network tunnel information corresponding to the access network device; and sending the first core network tunnel information to the second access network device.

[0039] For example, when a terminal establishes a session through a first access network device, the first access network device requests the user plane functional network element to allocate core network tunnel information for the session. The request may carry information of other access network devices, and the other access network devices may include all or part of the access network devices whose coverage includes the location of the terminal except the first access network device, for example, the second access network device and the third access network device. According to the request, the user plane functional network element may allocate core network tunnel information for the session, and the core network tunnel information corresponds to the other access network devices, for example, the second access network device corresponds to the second core network tunnel information, and the third access network device corresponds to the third core network tunnel information. Further, the user plane functional network element may send the allocated core network tunnel information to the corresponding access network device through the first access network device, or may send it to the corresponding access network device through the AMF, that is, send the second core network tunnel information to the second access network device, and send the third core network tunnel information to the third access network device.

[0040] In a possible implementation manner, the terminal is a stationary terminal.

[0041] In a possible implementation, before determining to switch the terminal to the second access network device based on the first switching time information of the terminal, the method also includes: the first access network device determines whether the terminal is a stationary terminal, and determines to switch the terminal to the second access network device based on the first switching time information of the terminal.

[0042] In a possible implementation manner, the first access network device obtains (or determines) first switching time information when determining that the terminal is a stationary terminal.

[0043] In a third aspect, the present application provides a communication method, which is applied to an access and mobility management functional network element, and the method includes: based on the second switching time information of the terminal, determining to switch the terminal from a first access network device to a second access network device, the second switching time information including the time when at least one access network device serves the terminal, and the at least one access network device includes the second access network device; sending a first message to the session management functional network element, the first message being used to update the access network tunnel information of the terminal.

[0044] In an embodiment of the present application, AMF actively triggers the execution of the corresponding process for UE switching to the second access network device based on the second switching time information, which may specifically include sending the above-mentioned first message to the session management function network element (SMF), without relying on the path switching message sent by the second access network device, thereby improving the switching efficiency and alleviating the communication pressure of the NG interface.

[0045] In a possible implementation, the first message includes one or more of the following: access network tunnel information allocated by the second access network device to the terminal; an identifier of the second access network device; and an identifier of the first session of the terminal.

[0046] In a possible implementation manner, when the first message includes the identifier of the first session, the first message is specifically used to update the access network tunnel information of the first session.

[0047] For example, when the access network tunnel information corresponds to only one session, and the one session is the first session, assuming that the SMF stores the access network tunnel information corresponding to the identifier of the access network device and the identifier of the session, the first message may include the identifier of the first session and the identifier of the second access network device. Accordingly, after receiving the first message, the SMF may update the access network tunnel information of the first session based on the identifier of the first session and the identifier of the second access network device.

[0048] For example, when the access network tunnel information corresponds to only one session, and the one session is the first session, assuming that the second access network device allocates the first access network tunnel information to the first session, the first message may include the identifier of the first session and the first access network tunnel information. Accordingly, after receiving the first message, the SMF may update the access network tunnel information of the first session based on the identifier of the first session and the access network tunnel information.

[0049] In a possible implementation, the method also includes: the access and mobility management function network element determines the second switching time information based on the access time of the terminal accessing the at least one access network device respectively during the satellite operation cycle; or, the access and mobility management function network element determines the second switching time information based on the position and ephemeris information of the terminal.

[0050] In a possible implementation, the method further includes: receiving access network tunnel information allocated by the second access network device to the terminal; and sending the access network tunnel information allocated by the second access network device to the terminal to the session management function network element.

[0051] In an embodiment of the present application, the access network tunnel information allocated by the second access network device to the terminal can be sent to the AMF through the first access network device. For example, when the terminal accesses the first access network device, the first access network device requests other access network devices (including the second access network device) to allocate access network tunnel information to the terminal, and the first access network device sends the access network tunnel information allocated by the other access network devices to the terminal to the AMF after receiving it. Alternatively, the access network tunnel information allocated by the second access network device to the terminal can also be sent directly to the AMF by the second access network device. For example, after the second access network device receives the above-mentioned switching request message, the second access network device sends the access network tunnel information to the AMF, or when the terminal previously accesses the second access network device, the second access network device sends it to the AMF, and the AMF receives and stores the access network tunnel information. When the AMF determines to switch the terminal to the second access network device, it sends the above-mentioned first message to the SMF based on the access network tunnel information.

[0052] In a possible implementation manner, the access network tunnel information includes aggregated access network tunnel information.

[0053] In a possible implementation, before determining to switch the terminal to the second access network device based on the second switching time information of the terminal, the method further includes: receiving a terminal identifier assigned to the terminal by other access network devices from the first access network device, the other access network devices including one or more access network devices other than the first access network device among the at least one access network device; after determining to switch the terminal to the second access network device, the method further includes: based on the terminal identifier assigned to the terminal by the other access network devices, updating the terminal identifier of the terminal recorded in the access and mobility management function network element to the terminal identifier assigned to the terminal by the second access network device.

[0054] In a possible implementation manner, the coverage of the at least one access network device includes the location of the terminal.

[0055] Specifically, all ranges of signal coverage of each of the at least one access network device during operation include the location of the terminal. It should be noted that all ranges of signal coverage of the access network device during operation include the location of the terminal, which means that when the access network device operates to a certain position (for example, the upper left, upper right, or directly above the terminal), the signal coverage of the access network device includes the location of the terminal, rather than that the communication coverage of the access network device at every moment during the entire operation process includes the location of the terminal.

[0056] In one possible implementation, the terminal is a stationary terminal. In some possible implementations, determining to switch the terminal to the second access network device based on the first switching time information of the terminal specifically includes: when the terminal is a stationary terminal, determining to switch the terminal to the second access network device based on the first switching time information of the terminal.

[0057] In a fourth aspect, the present application provides a communication method applied to a session management function network element, the method comprising: receiving a first message from an access and mobility management function network element, the first message being used to update the access network tunnel information of a terminal, the first message comprising an identifier of a second access network device; based on the identifier of the second access network device, allocating access network tunnel information to the terminal; and sending the allocated access network tunnel information to a user plane function network element, the allocated access network tunnel information being used by the user plane function network element to update the access network tunnel information of the terminal.

[0058] In the embodiment of the present application, the allocated access network tunnel information is the access network tunnel information allocated to the terminal based on the identifier of the second access network device.

[0059] By adopting the communication method provided in the present application, SMF allocates access network tunnel information to the terminal, so that there is no need for signaling interaction about the access network tunnel information between the access network device and AMF, thereby further reducing the signaling interaction time in the switching process and improving the switching efficiency.

[0060] In a possible implementation manner, the method further includes: sending core network tunnel information of the terminal to the second access network device.

[0061] In a possible implementation manner, the method further includes: sending the allocated access network tunnel information to the second access network device.

[0062] In a fifth aspect, the present application provides a communication method, applied to a session management function network element, the method comprising: receiving access network tunnel information allocated to a terminal by a second access network device from an access and mobility management function network element; receiving a first message from the access and mobility management function network element, the first message being used to update the access network tunnel information of the terminal, the first message including an identifier of the second access network device; based on the identifier of the second access network device, sending the access network tunnel information allocated to the terminal by the second access network device to a user plane function network element, the access network tunnel information being used by the user plane function network element to update the access network tunnel information of the terminal.

[0063] Specifically, before the terminal accesses the second access network device, SMF receives the access network tunnel information allocated by the second access network device to the terminal from AMF. When the terminal accesses the second access network device, SMF receives the first message from AMF, and SMF determines the access network tunnel information of the second access network device serving the terminal based on the identifier of the second access network device carried in the first message, and sends the access network tunnel information to the user plane functional network element.

[0064] By adopting the communication method provided in the present application, when the terminal accesses the second access network device, the access network tunnel information of the second access network device serving the terminal has been stored in the SMF, so that the AMF does not need to send the access network tunnel information of the second access network device serving the terminal to the SMF through the first message, and the second access network device also does not need to send the access network tunnel information of the second access network device serving the terminal to the AMF, thereby reducing the signaling interaction during the switching process, alleviating the communication pressure, and further improving the switching efficiency.

[0065] In a possible implementation manner, before receiving the first message from the access and mobility management function network element, the method further includes: sending the core network tunnel information of the terminal to the second access network device.

[0066] In a sixth aspect, the present application provides a communication system, the system comprising a first access network device, a second access network device, and an access and mobility management function network element; wherein the second access network device is used to execute the method shown in the first aspect or any possible implementation of the first aspect; the first access network device is used to execute the method shown in the second aspect or any possible implementation of the second aspect; the access and mobility management function network element is used to execute the method shown in the third aspect or any possible implementation of the third aspect.

[0067] In one possible implementation, the system also includes a session management function network element; the session management function network element is used to execute the method shown in the fourth aspect or any possible implementation of the fourth aspect; or, the session management function network element is used to execute the method shown in the fifth aspect or any possible implementation of the fifth aspect.

[0068] In the seventh aspect, the present application provides a communication method applied to a session management function network element, the method comprising: receiving second switching time information from an access and mobility management function network element, the second switching time information including the access time of at least one access network device corresponding to the terminal; based on the second switching time information, determining to switch the terminal to a second access network device; and requesting the user plane function network element to update the access network tunnel information of the terminal to the access network tunnel information of the second access network device serving the terminal.

[0069] By adopting the communication method provided in the present application, the session management function network element actively triggers the execution of the relevant process of switching the UE to the second access network device based on the second switching time information, without waiting for the synchronization message (such as an update request message) sent by the AMF about switching the terminal to the second access network device, thereby alleviating the communication pressure of the N11 interface and improving the switching efficiency.

[0070] In a possible implementation, before determining to switch the terminal to the second access network device based on the second switching time information, the method also includes: receiving access network tunnel information allocated to the terminal by other access network devices from an access and mobility management function network element, the other access network devices including one or more access network devices of the at least one access network device other than the first access network device.

[0071] In a possible implementation manner, the access network tunnel information of the second access network device serving the terminal includes aggregated access network tunnel information allocated by the second access network device to the terminal.

[0072] In a possible implementation manner, the access network tunnel information of the second access network device serving the terminal includes access network tunnel information allocated by the second access network device to the first session of the terminal.

[0073] In a possible implementation manner, the access network tunnel information of the second access network device serving the terminal is allocated by the session management function network element.

[0074] In a possible implementation, after determining to switch the terminal to the second access network device based on the second switching time information, the method further includes: sending the access network tunnel information to the second access network device and / or the access and mobility management function network element.

[0075] In an eighth aspect, the present application provides a communication method, which is applied to an access and mobility management function network element, and the method includes: determining second switching time information of a terminal, the second switching time information including the access time of at least one access network device corresponding to the terminal; and sending the second switching time information to a session management function network element.

[0076] In a possible implementation, the method also includes: obtaining access network tunnel information allocated by other access network devices to the terminal, the other access network devices including one or more access network devices other than the first access network device among the at least one access network device; and sending the access network tunnel information allocated by other access network devices to the terminal to the session management function network element.

[0077] In the ninth aspect, the present application provides a communication system, the system comprising an access and mobility management function network element and a session management function network element, the access and mobility management function network element being used to execute the method shown in the eighth aspect or any possible implementation of the eighth aspect, and the session management function network element being used to execute the method shown in the seventh aspect or any possible implementation of the seventh aspect.

[0078] In one possible implementation, the system also includes a first access network device and a second access network device, the first access network device is used to execute the method shown in the second aspect or any possible implementation of the second aspect, and the second access network device is used to execute the method shown in the first aspect or any possible implementation of the first aspect.

[0079] In the tenth aspect, the present application provides a communication method applied to a session management function network element, the method comprising: receiving second information from an access and mobility management function network element, the second information comprising access times corresponding to the terminal accessing at least one access network device and access network tunnel information respectively allocated by the at least one access network device to the terminal; based on the second information, determining to switch the terminal to a second access network device; and requesting the user plane function network element to update the access network tunnel information of the terminal to the access network tunnel information of the second access network device serving the terminal.

[0080] By adopting the communication method provided in the present application, the session management function network element actively triggers the execution of the relevant process of switching the UE to the second access network device based on the second information, without waiting for the synchronization message (such as an update request message) sent by the AMF about switching the terminal to the second access network device, thereby alleviating the communication pressure of the N11 interface and improving the switching efficiency.

[0081] In a possible implementation, the second information includes second switching time information and access network tunnel information allocated by other access network devices to the terminal, and the second switching time information includes access time of at least one access network device corresponding to the terminal.

[0082] In a possible implementation manner, the second information includes a correspondence between an identifier of the session of the terminal, an access time when the terminal accesses a corresponding access network device, and access network tunnel information.

[0083] In the eleventh aspect, the present application provides a communication method, which is applied to an access and mobility management functional network element, and the method includes: determining the second switching time information of the terminal; obtaining the access network tunnel information allocated to the terminal by other access network devices, and the other access network devices include one or more access network devices other than the first access network device in the at least one access network device; based on the second switching time information and the access network tunnel information allocated to the terminal by the other access network devices, sending second information to the session management functional network element, the second information including the access time corresponding to the terminal accessing at least one access network device and the access network tunnel information allocated by the at least one access network device to the terminal.

[0084] In a possible implementation, the second information includes second switching time information and access network tunnel information allocated by other access network devices to the terminal, and the second switching time information includes access time of at least one access network device corresponding to the terminal.

[0085] In a possible implementation manner, the second information includes a correspondence between an identifier of the session of the terminal, an access time when the terminal accesses a corresponding access network device, and access network tunnel information.

[0086] In a twelfth aspect, the present application provides a communication system, the system comprising an access and mobility management function network element and a session management function network element, the access and mobility management function network element being used to execute the method shown in the eleventh aspect or any possible implementation of the eleventh aspect, and the session management function network element being used to execute the method shown in the tenth aspect or any possible implementation of the tenth aspect.

[0087] In one possible implementation, the system also includes a first access network device and a second access network device, the first access network device is used to execute the method shown in the second aspect or any possible implementation of the second aspect, and the second access network device is used to execute the method shown in the first aspect or any possible implementation of the first aspect.

[0088] In a thirteenth aspect, the present application provides a communication device, comprising a unit for executing the method shown in any possible implementation of one or more of the first aspect, the second aspect, the third aspect, the fourth aspect, the fifth aspect, the seventh aspect, the eighth aspect, the tenth aspect, and the eleventh aspect.

[0089] In a fourteenth aspect, the present application provides a communication device, comprising a processor, wherein the processor is used to execute the method shown in any possible implementation manner in one or more of the first aspect, the second aspect, the third aspect, the fourth aspect, the fifth aspect, the seventh aspect, the eighth aspect, the tenth aspect, and the eleventh aspect.

[0090] In a fifteenth aspect, the present application provides a communication device, comprising a logic circuit and an interface, wherein the logic circuit and the interface are coupled; the interface is used to input and / or output information, and the logic circuit is used to execute the method shown in any possible implementation manner in one or more of the first aspect, the second aspect, the third aspect, the fourth aspect, the fifth aspect, the seventh aspect, the eighth aspect, the tenth aspect, and the eleventh aspect.

[0091] In the sixteenth aspect, a computer-readable storage medium is used to store a computer program. When the computer program is executed, the method shown in any possible implementation of one or more of the first aspect, the second aspect, the third aspect, the fourth aspect, the fifth aspect, the seventh aspect, the eighth aspect, the tenth aspect, and the eleventh aspect is executed.

[0092] In the seventeenth aspect, the present application provides a computer program, which, when executed, enables the method shown in any possible implementation manner in one or more of the above-mentioned first aspect, second aspect, third aspect, fourth aspect, fifth aspect, seventh aspect, eighth aspect, tenth aspect, and eleventh aspect to be executed.

[0093] In the eighteenth aspect, the present application provides a computer program product, which includes a computer program or a computer code, which, when executed on a computer, enables the method shown in any possible implementation manner in one or more of the above-mentioned first aspect, second aspect, third aspect, fourth aspect, fifth aspect, seventh aspect, eighth aspect, tenth aspect, and eleventh aspect to be executed.

[0094] In the nineteenth aspect, an embodiment of the present application provides a chip system, which is applied to an electronic device, and the chip system includes one or more processors, which are used to call computer instructions so that the electronic device executes the method shown in any possible implementation manner of one or more of the above-mentioned first aspect, second aspect, third aspect, fourth aspect, fifth aspect, seventh aspect, eighth aspect, tenth aspect, and eleventh aspect.

[0095] It is understandable that the communication device, communication system, computer storage medium, computer program, computer program product, and chip system provided above are all used to execute the method shown in any implementation of the corresponding aspects of the embodiments of the present application. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0097] Figure 2 It is a schematic diagram of the architecture of another communication system provided in an embodiment of the present application;

[0098] Figure 3 It is a schematic diagram of a switching process of a terminal switching to a target access network device in another communication method provided in an embodiment of the present application;

[0099] Figure 4 It is a method flow diagram of a communication method provided by an embodiment of the present application;

[0100] Figure 5A It is a schematic diagram of different sources of core network tunnel information provided by an embodiment of the present application;

[0101] Figure 5B It is a schematic diagram of another different source method of access network tunnel information provided by an embodiment of the present application;

[0102] Figure 5C This is another schematic diagram of different sources of terminal identification provided by an embodiment of the present application;

[0103] Figure 6 This is a method flow diagram of another communication method provided by an embodiment of the present application;

[0104] Figure 7 This is a method flow diagram of another communication method provided by an embodiment of the present application;

[0105] Figure 8 This is a method flow diagram of another communication method provided by an embodiment of the present application;

[0106] Fig. 9 This is a method flow diagram of another communication method provided by an embodiment of the present application;

[0107] Fig.10 This is a method flow diagram of another communication method provided by an embodiment of the present application;

[0108] Fig.11 This is a method flow chart of another communication method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0109] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described below in conjunction with the accompanying drawings.

[0110] The terms "first" and "second" in the specification, claims and drawings of this application are only used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0111] The "embodiment" mentioned in this document means that the specific features, structures or characteristics described in conjunction with the embodiment can be included in one or more embodiments of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It can be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0112] In the present application, "one or more (items)" refers to one or more, "multiple" refers to two or more, "at least two (items)" refers to two or three and more than three, and "and / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and following associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0113] The method provided in the embodiment of the present application can be applied to a satellite communication system under a regenerated payload mode in a non-terrestrial network (NTN), such as Figure 1 As shown, the communication system may include a terminal, a satellite, a ground station (also referred to as a gateway station, a signal gateway station), an access and mobility management function network element (access and mobility management function, AMF), a session management function network element (session management function, SMF), and a user plane function network element (user plane function, UPF).

[0114] In the satellite communication system scenario of the regenerative load mode, the radio access network equipment (RAN) can be deployed on the satellite, for example, all or part of the functions of the base station (RAN) are deployed on the satellite, and the satellites can complete the signaling interaction and user data transmission between base stations. The access network equipment described in this application can be a wireless access network equipment. With the evolution of standard technology, the access network equipment can also be network equipment of other standards, which is not limited in this article.

[0115] Figure 1 The air interface is the wireless link between the terminal and RAN; the Xn interface is the interface between RAN and RAN, which is mainly used for signaling interaction such as switching; the NG interface is the interface between RAN and AMF. In some descriptions, the NG interface is also called the N2 interface, which is used for signaling such as non-access stratum (NAS) of the interactive core network and user service data.

[0116] A terminal is a device with wireless transceiver functions. The terminal can communicate with an access network device (or also referred to as an access device) in a radio access network (RAN), for example, it can access the RAN in a satellite through an air interface and initiate calls, Internet access and other services. A terminal may also be referred to as user equipment (UE), access terminal, terminal, subscriber unit, user station, mobile station, remote station, remote terminal, mobile device, user terminal, user agent or user device, etc. In one possible implementation, the terminal may be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; it may also be deployed on the water surface (such as a ship, etc.). In one possible implementation, the terminal may be a handheld device with wireless communication function, a vehicle-mounted device, a wearable device, a sensor, a terminal in the Internet of Things, a terminal in the Internet of Vehicles, a drone, a fifth generation (5G) network and any form of terminal in future networks, etc., which is not limited in the embodiments of the present application. Exemplarily, the terminals can also communicate with each other through device-to-device (D2D), machine-to-machine (M2M), etc. The terminal shown in the embodiment of the present application can also be a device in the Internet of Things (IoT). The IoT network can include, for example, the Internet of Vehicles. Among them, the communication methods in the Internet of Vehicles system are collectively referred to as vehicle to other devices (vehicle to X, V2X, X can represent anything). For example, the V2X can include: vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) communication or vehicle to network (V2N) communication, etc.

[0117] The ground station can be used to connect the satellite to the RAN, the satellite to the core network, and is responsible for forwarding signaling and service data between the satellite and the core network. The satellite can provide wireless access services for the terminal, schedule wireless resources to the accessed terminal, and provide reliable wireless transmission protocols and data encryption protocols. As an example, in a regenerative load mode, the satellite can be a base station (RAN) that uses artificial earth satellites and high-altitude aircraft as wireless communications, such as evolutionary NodeB (eNB) and next generation node B (gNB).

[0118] The core network may include AMF, SMF, UPF, etc., among which AMF may be responsible for user access management, security authentication, and mobility management, etc. UPF may be responsible for managing the transmission of user plane data, traffic statistics, etc.

[0119] In the embodiment of the present application, the satellite may be a medium earth orbit (MEO) satellite or a low earth orbit (LEO) satellite of a non-geostationary earth orbit (NGEO), or a high altitude platform station (HAPS), etc. The embodiment of the present application does not limit the specific type of the satellite.

[0120] In some deployments of RAN, RAN may include a centralized unit (CU) and a distributed unit (DU). In other deployments of RAN, CU may also be divided into CU-control plane (CP) and CU-user plane (UP). In some other deployments of RAN, RAN may also be an open radio access network (ORAN) architecture, etc., and the embodiments of the present application do not limit the specific deployment mode of RAN. Exemplarily, when RAN is an ORAN architecture, the RAN shown in the embodiments of the present application may be an access network device in ORAN, or a functional module, etc. In the ORAN system, CU may also be referred to as an open (open, O)-CU, DU may also be referred to as O-DU, CU-CP may also be referred to as O-CU-CP, CU-UP may also be referred to as O-CU-UP, etc. The deployment modes of RAN listed here are only examples. With the evolution of standard technologies, RAN may have other deployment forms.

[0121] Understandable, Figure 1Only one satellite and one ground station are shown. In actual use, a multi-satellite and / or multi-ground station architecture can be adopted as needed. Among them, each satellite can provide services to one or more terminals, each satellite can correspond to one or more ground stations, each ground station can correspond to one or more satellites, etc., which are not specifically limited in the embodiments of the present application. The method provided in the embodiments of the present application can be applied to the Internet of Things (IoT) system, the Vehicle to X (V2X), and the narrowband Internet of Things (NB-IoT) system; for example, it can be applied to the LTE frequency division duplex (FDD) system, the LTE time division duplex (TDD), the long term evolution (LTE) system, the fifth generation (5G) communication system, the sixth generation (6G) communication system or the future communication system, etc., which are not specifically limited in the embodiments of the present application.

[0122] The following is an introduction to the communication architecture between network elements included in the communication system applied in this application:

[0123] Figure 2 This is a schematic diagram of the communication network architecture between network elements included in a communication system in an embodiment of the present application, which takes the 5G network architecture based on the service-oriented architecture in the non-roaming scenario defined in the 3GPP standardization process as an example. The network architecture may include three parts, namely, the terminal part, the 5G system and the data network (DN).

[0124] The terminal part may include a terminal 310, which may also be referred to as user equipment (UE). The terminal 310 in the present application is a device with wireless transceiver functions, which may communicate with one or more core network (CN) devices (or may also be referred to as core devices) via an access network device (or may also be referred to as an access device) in a radio access network (RAN) 340. The terminal 310 may also be referred to as an access terminal, a terminal, a user unit, a user station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a user agent or a user device, etc. The terminal 310 may be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; it may also be deployed on the water (such as a ship, etc.); it may also be deployed in the air (such as an airplane, a balloon, and a satellite, etc.). The terminal 310 may be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a smart phone, a mobile phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), etc. Alternatively, the terminal 310 may also be a handheld device with wireless communication function, a computing device or other device connected to a wireless modem, a vehicle-mounted device, a wearable device, a drone device or a terminal in the Internet of Things or the Internet of Vehicles, a terminal in any form in a 5G network and future networks, a relay user device or a terminal in a future evolved 5G system, etc. Among them, the relay user device may be, for example, a 5G residential gateway (RG). For example, the terminal 310 may be a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. The embodiment of the present application does not limit the type or category of the terminal.

[0125] The 5G system may include: a network exposure function (NEF) 331, a network function repository function (NRF) 332, a policy control function (PCF) 333, a unified data management (UDM) 334, an application function (AF) 335, an authentication server function (AUSF) 336, an access and mobility management function network element (AMF) 337, a session management function (SMF) network element 338, a user plane function (UPF) network element 339, and a radio access network (RAN) 340. In the above 5G system, the part other than the (radio) access network 340 may be referred to as a core network (CN) part or a core network part.

[0126] Data network DN 320, also known as packet data network (PDN), is usually a network located outside the 5G system, such as a third-party network. Exemplarily, the 5G system can access multiple data networks DN 320, and multiple services can be deployed on the data network DN 320 to provide data and / or voice services to the terminal 310. For example, the data network DN 320 can be a private network of a smart factory, and the sensors installed in the workshop of the smart factory can be the terminals 310. The control server of the sensors is deployed in the data network DN 320, and the control server can provide services for the sensors. The sensors can communicate with the control server, obtain instructions from the control server, and transmit the collected sensor data to the control server according to the instructions. For another example, the data network DN 320 can be the internal office network of a company, and the mobile phones or computers of the company's employees can be the terminals 310. The employees' mobile phones or computers can access the information, data resources, etc. on the company's internal office network. The terminal 310 can access the company's internal office network through the interface provided by the 5G system (for example Figure 2The terminal 310 establishes a connection with the 5G system through the N1 interface in the 5G system, and uses the data and / or voice services provided by the 5G system. The terminal 310 can also access the data network DN 320 through the 5G system, use the operator services deployed on the data network DN 320, and / or the services provided by a third party. Among them, the third party may be a service provider other than the 5G system and the terminal 310, and may provide other data and / or voice services to the terminal 310. Among them, the specific form of expression of the third party can be determined according to the actual application scenario, and is not limited here.

[0127] As an example, the network functions in the 5G system are briefly introduced below.

[0128] RAN 340 is a subnetwork of the 5G system and is an implementation system between a service node (or network function) and a terminal 310 in the 5G system. To access the 5G system, the terminal 310 first passes through RAN 340 and then connects to a service node in the 5G system through RAN 340. The access network device in the embodiment of the present application is a device that provides wireless communication functions for the terminal 310, and may also be referred to as an access device, RAN device, or network device. For example, the access device includes but is not limited to: the next generation node basestation (gNB) in the 5G system, the evolved node B (eNB) in the LTE system, the radio network controller (RNC), the node B (NB), the base station controller (BSC), the base transceiver station (BTS), the home evolved node B (or home node B, HNB), the base band unit (BBU), the transmission and receiving point (TRP), the transmitting point (TP), the small base station equipment (pico), the mobile switching center, or the network equipment in the future network, etc. It is understandable that the present application does not limit the specific type of access network equipment. In systems using different wireless access technologies, the names of devices with access network equipment functions may be different.

[0129] Optionally, in some deployments of access devices, the access device may include a centralized unit (CU) and a distributed unit (DU). In other deployments of access devices, the CU may also be divided into a CU-control plane (CP) and a CU-user plane (UP). In still other deployments of access devices, the access device may also be an open radio access network (ORAN) architecture, etc. This application does not limit the specific deployment method of the access device.

[0130] The network open function NEF (also referred to as NEF network function or NEF network function entity) 331 is a control plane function provided by the operator. The NEF network function 331 opens the external interface of the 5G system to a third party in a secure manner. When the SMF needs to communicate with the network function of a third party, the NEF network function 331 can serve as a relay for the communication between the SMF and the network entity of the third party. When the NEF network function 331 acts as a relay, it can be used to translate the identification information of the contracted user, as well as the identification information of the network function of the third party. For example, when the NEF network function 331 sends the subscriber permanent identifier (SUPI) of the contracted user from the 5G system to a third party, the SUPI can be translated into its corresponding external identity (ID). Conversely, when the NEF network function 331 sends an external ID (network entity ID of a third party) to the 5G system, it can be translated into SUPI.

[0131] The network storage function NRF 332 can be used to maintain real-time information of all network function services in the network.

[0132] The policy control function PCF 333 is a control plane function provided by the operator, and is used to provide the protocol data unit (PDU) session policy to the session management function network element SMF 338. The policy may include charging-related policies, QoS-related policies, and authorization-related policies.

[0133] Unified data management UDM 334 is a control plane function provided by the operator, which is responsible for storing information such as the subscriber permanent identifier (SUPI), security context, and contract data of the subscribers in the 5G system. The subscribers of the above-mentioned 5G system may specifically be users who use the services provided by the 5G system, such as users who use the terminal chip card of China Telecom, or users who use the terminal chip card of China Mobile, etc. Exemplarily, the SUPI of the subscriber may be the number of the terminal chip card, etc. The above-mentioned security context may be data (cookie) or a token stored on a local terminal (such as a mobile phone). The contract data of the above-mentioned subscriber may be the supporting services of the terminal chip card, such as the traffic package of the mobile phone chip card, etc.

[0134] The application function AF 335 is used to perform data routing affected by the application, access network open functions, interact with the policy framework for policy control, etc.

[0135] The authentication server function AUSF 336 is a control plane function provided by the operator, which is usually used for level 1 authentication, i.e. authentication between the terminal 310 (subscribed user) and the 5G system.

[0136] The access and mobility management function network element AMF 337 is a control plane network function provided by the 5G system, which is responsible for the access control and mobility management of the terminal 310 to the 5G system, such as mobile state management, allocation of user temporary identity, authentication and authorization of users, etc.

[0137] The session management function network element SMF 338 is a control plane network function provided by the 5G system, which is responsible for managing the protocol data unit (PDU) session of the terminal 310. The PDU session is a channel for transmitting PDUs. The terminal needs to transmit PDUs to and from the DN 320 through the PDU session. The PDU session can be established, maintained, and deleted by SMF 338. SMF 338 includes session management (such as session establishment, modification, and release, including tunnel maintenance between UPF 339 and RAN 340, etc.), selection and control of UPF 339, service and session continuity (SSC) mode selection, roaming and other session-related functions.

[0138] The user plane function UPF 339 is a gateway provided by the operator and is the gateway for the 5G system to communicate with the DN 320. UPF339 includes user plane related functions such as data packet routing and transmission, packet detection, service usage reporting, quality of service (QoS) processing, legal monitoring, uplink packet detection, downlink packet storage, etc.

[0139] Figure 2 The network functions in the 5G system shown may also include a network slice selection function (NSSF) ( Figure 2 (not shown) is responsible for determining the network slice instance, selecting the network function of AMF, etc. Figure 2 The network functions in the 5G system shown may also include a unified data repository (UDR), etc. The embodiments of the present application do not limit other network functions included in the 5G system.

[0140] Figure 2 Where Nnef, Nausf, Nnrf, Npcf, Nudm, Naf, Namf, Nsmf, N1, N2, N3, N4, and N6 are interface serial numbers. For example, the meaning of the above interface serial numbers can refer to the meaning defined in the 3GPP standard protocol, and this application does not limit the meaning of the above interface serial numbers. It should be noted that, Figure 2 In the example, only the terminal 310 is used as the UE. Figure 2 The interface name between the various network functions is just an example. In a specific implementation, the interface name of the system architecture may also be other names, and this application does not limit this.

[0141] The mobility management network function in this application can be Figure 2 The AMF 337 shown may also be other network functions in future communication systems having the above-mentioned access and mobility management function network element AMF 337. Alternatively, the mobility management network function in the present application may also be a mobility management entity (mobility management entity, MME) in an LTE system, etc.

[0142] For the convenience of explanation, in the embodiment of the present application, the access and mobility management function network element AMF 337 is referred to as AMF, the unified data management UDM 334 is referred to as UDM, and the terminal 310 is referred to as UE, that is, the AMF described later in the embodiment of the present application can be replaced by a mobility management network function, the UDM can be replaced by a unified data management, and the UE can be replaced by a terminal. It can be understood that other network functions not shown are also applicable to the replacement method.

[0143] Figure 2 The network architecture shown in the figure (such as the 5G network architecture) adopts a service-based architecture and a universal interface. The traditional network element functions are split into several self-contained, self-managed, and reusable network function service modules based on network function virtualization (NFV) technology. Figure 2 The network architecture diagram shown in the figure can be understood as a service-based 5G network architecture diagram in a non-roaming scenario. In this architecture, different network functions are combined in an orderly manner according to the needs of specific scenarios, which can realize the customization of network capabilities and services, thereby avoiding the deployment of dedicated physical networks for different services. Network slicing technology can enable operators to respond to customer needs more flexibly and quickly, and support flexible allocation of network resources.

[0144] The following introduces the terms involved in the embodiments of the present application.

[0145] (1) Access network tunnel information, core network tunnel information, and path switching messages

[0146] The access network tunnel information refers to the address of the access network device used when the UPF sends information related to the terminal (such as downlink data) to the access network device. The core network tunnel information refers to the address of the UPF used when the access network device sends information related to the terminal (such as uplink data) to the UPF. In some descriptions in this application, for the sake of ease of description, the tunnel information used to carry data about the terminal between the access network device and the user plane functional network element is described as the access network tunnel information or core network tunnel information of the access network device serving the terminal, which can specifically be the access network tunnel information or core network tunnel information of the access network device and / or user plane functional network element serving the terminal or the session of the terminal. It should be noted that the specific definition of the access network tunnel information and the core network tunnel information depends on the protocol standard.

[0147] Generally, in the switching process from the terminal to the target access network device, after the air interface switching of the UE is completed between the source access network device and the target access network device, the target access network device sends a path switching message to the AMF. The path switching message is used to switch the path of the terminal. For example, the English name of the path switching message can be N2 path switch, pathswitch, or N2 path switch request, which is not limited in this article.

[0148] As an example, the path switching message is used to instruct (or trigger) AMF to request UPF through SMF to allocate core network tunnel information to the terminal, and to switch the N3 path used by UPF to send and / or receive relevant information of the terminal from the source access network device to the target access network device.

[0149] In addition, after UPF responds to the request of SMF, allocates core network tunnel information to the terminal and sends it to the target access network device, the target access network device then sends the access network tunnel information allocated by the target access network device to the terminal to UPF (specifically, the access network tunnel information can be sent to UPF through AMF and SMF), so that the target access network device and UPF communicate based on the core network tunnel information and the access network tunnel information. Alternatively, in some other possible implementations, the path switching message can also carry the access network tunnel information allocated by the target access network device to the terminal, which is not limited in this document. However, it should be noted that by sending the access network tunnel information allocated by the target access network device to the terminal to UPF through the path switching message in step S303, there is no need to wait for UPF to allocate core network tunnel information to the terminal before the access network device allocates access network tunnel information to the terminal, which can shorten the communication time involved in executing the switching process and improve the switching efficiency.

[0150] In the embodiment of the present application, the core network tunnel information and the access network tunnel information can serve the same session. The core network tunnel information and the access network tunnel information can only serve one session, or can only serve the session of the same slice, or can only serve the session of the same terminal accessing the same access network device, or can serve the session of all terminals accessing the same access network device, which is not limited in this document.

[0151] For the convenience of description, tunnel information (core network tunnel information and access network tunnel information) that can only serve one session is called session-granularity tunnel information; tunnel information that can only serve a slice session is called slice-granularity tunnel information; tunnel information that can only serve sessions of the same terminal accessing the same access network device is called UE-RAN-granularity tunnel information; core network tunnel information and access network tunnel information that can serve sessions of all terminals accessing the same access network device are called RAN-granularity tunnel information. Among them, tunnels of session granularity, slice granularity, UE-RAN granularity, and RAN granularity can all be called aggregated tunnels. It should be noted that the service granularity of core network tunnel information and access network tunnel information is generally one-to-one corresponding. For example, if the core network tunnel information is session-granularity tunnel information, the access network tunnel information is also session-granularity tunnel information. However, this application does not limit the service granularity of core network tunnel information and access network tunnel information to only one-to-one corresponding, and this article does not limit this.

[0152] As another example, the time when AMF receives the path switch message is the time when the terminal accesses the second access network device. For example, AMF receives the path switch message of the terminal accessing RAN1 at time t1, and receives the path switch message of the terminal accessing RAN2 at time t2. Then the time period of RAN1 serving the terminal device is from t1 to t2.

[0153] (2) Terminal identification

[0154] In some possible implementations, based on communication security considerations, when the access network device and the AMF communicate about the terminal through the NG interface, they may not directly use the terminal identifier (UE ID) to identify the UE, but instead use the NG application protocol identifier (RAN UE NG Application Protocol Identity, RAN UE NGAPID) allocated by the access network device to the UE and another private identifier allocated by the AMF to the UE to identify each other. For the sake of description, this article refers to the RAN UE NGAPID as the terminal identifier.

[0155] In some possible implementations, in the terminal switching process, the path switching message sent by the target access network device to the AMF may also carry the terminal identifier assigned by the target access network device to the terminal, so as to enable or trigger the AMF to update the RAN UE NGAP ID locally stored in the AMF based on the terminal identifier.

[0156] The following introduces the technical background and technical problems solved by the embodiments of the present application.

[0157] In the regeneration transmission mode, the base station or part of the base station functions are deployed on the satellite, that is, the movement of the satellite will cause the wireless signal coverage of the radio access network (RAN) deployed on the satellite to change, and the satellite serving the UE needs to be replaced from the source access network device to the target access network device. Generally, low-orbit satellites are at a low altitude from the ground and move quickly. It is estimated that for a certain location on the ground, the time interval required from one satellite moving directly above the ground to the next satellite moving directly above the ground is only about 3 minutes, which makes the switching process of the UE switching from accessing the source access network device to accessing the target access network device occur frequently. For the sake of ease of description below, the process of switching the UE from accessing the source access network device to accessing the target access network device is called the switching process. In some other description methods, it can also be called the Xn switching process, which is not limited in this article.

[0158] For example, in some other communication methods, each time the UE performs a handover process, the target access network device will perform a series of signaling interactions with the core network. Figure 3 As shown, after the air interface handover of the UE is completed between the source access network device and the target access network device (corresponding to Figure 3 In step S302), the target access network device sends an N2 path switching request (corresponding to the N2 path switching request) to the AMF regarding the UE. Figure 3 Step S303 in step 100), thereby triggering AMF to send a session update request to SMF (corresponding to Figure 3 Step S304), and SMF sends an N4 session modification request (corresponding to step S305) to UPF in response to the session update request. Figure 3 In step S305), the UPF is requested to allocate the core network tunnel information of the terminal. After the UPF allocates the core network tunnel information of the terminal, the core network tunnel information allocated by the UPF to the terminal is sent to the target access network device through steps S306-S308. And, after the target access network device receives the core network tunnel information of the terminal, the access network tunnel information allocated by the target access network device to the terminal is sent to the UPF through step S309.

[0159] This communication method, on the one hand, involves a lot of signaling interactions related to the target access network device obtaining the core network tunnel information of the terminal. It takes a certain amount of response time for the target access network device to request and wait for the UPF to allocate the core network tunnel information to the terminal. From the perspective of the switching process of a single UE, the switching efficiency needs to be improved. In addition, the number of UEs served by the core network is large, and the low-orbit satellite moves at a fast speed. Each UE will switch to a different access network device more frequently. The same and different access network devices will frequently obtain the core network tunnel information of the terminal from the UPF, which can easily cause network congestion problems, resulting in the problem of the waiting time for the target access network device to wait for the user plane functional network element to allocate the core network tunnel information to the terminal, and the problem of the efficiency of UE switching access network devices.

[0160] On the other hand, the UE frequently switches to different access network devices, and the NG interface between the access network device and the AMF needs to frequently process the relevant signaling interactions about the Xn switching (for example, steps S303, S308, and S309), which causes the signaling storm problem of the NG interface, and the communication pressure problem needs to be solved.

[0161] In view of this, an embodiment of the present application provides a communication method to improve the switching efficiency of the UE switching process.

[0162] Among them, in a communication method provided in an embodiment of the present application, after the first access network device determines that the UE switches to the second access network device based on the first switching time information, it sends a switching request message about the UE to the second access network device, and the first switching time information includes the access times corresponding to the UE accessing different RANs. After receiving the switching request message, the second access network device communicates with the UPF based on the switching request message and the core network tunnel information of the terminal stored in the second access network device. The AMF sends a first message about the UE to the SMF based on the second switching time information after determining that the UE switches to the second access network device. The second switching time information includes the access times corresponding to the UE accessing different RANs. The first message is used to request the SMF to update the access network tunnel information of the terminal's session to the access network tunnel information of the session of the terminal served by the second access network device.

[0163] By adopting the communication method provided in the present application, after the second access network device receives the switching request message of the terminal, it communicates with the UPF based on the core network tunnel information of the terminal established between the second access network device and the UPF, and does not need to send a path switching message to the AMF to request the UPF to allocate the core network tunnel information to the terminal. Therefore, on the one hand, the process of the second access network device requesting and waiting for the UPF to allocate the core network tunnel information to the terminal in the switching process is omitted, thereby improving the switching efficiency of the terminal frequently executing the switching process. On the other hand, the problem of communication pressure on the NG interface caused by the terminal frequently executing the switching process is avoided. For example, the second access network device does not need to send a message such as "Resume" to the AMF to avoid communication pressure on the NG interface caused by the terminal frequently executing the switching process. Figure 3 The N2 path switching request in step S303 shown in the figure does not need to be sent by the AMF to the second access network device as shown in step S308. On the other hand, the AMF cooperates with the execution of the corresponding process of the UE switching to the second access network device (for example, updating the RAN UE NGAP IP corresponding to the terminal, and sending the first message corresponding to the terminal to the SMF) based on the second switching time information to ensure the consistency and integrity of the UE switching process.

[0164] As an example, the core network tunnel information of the terminal stored in the second access network device may be allocated by the UPF to the terminal when the terminal accesses the second access network device in the previous satellite operation cycle, or may be allocated by the third access network device to the terminal and sent to the second access network device by requesting the UPF before the second access network device receives the switching request message.

[0165] exist Figure 3In the other communication methods shown, the signaling interaction for sending the access network tunnel information allocated by the target access network device to the terminal to the UPF also requires a certain execution time. When multiple UEs frequently execute the switching process, the signaling interaction related to the access network tunnel information will also have a certain adverse impact on the switching efficiency.

[0166] In view of this, in the communication method provided by the present application, the SMF can also allocate access network tunnel information to the terminal, so that the AMF does not need to wait for the access network tunnel information allocated by the second access network device to the terminal, and does not need to send the access network tunnel information allocated by the second access network device to the terminal to the SMF, thereby further improving the switching efficiency.

[0167] Alternatively, in the communication method provided in the present application, before the terminal currently accesses the second access network device, the access network tunnel information allocated by the second access network device to the terminal is sent to the AMF in advance. When the terminal accesses the second access network device, the second access network device no longer needs to send the access network tunnel information allocated to the terminal to the AMF. For example, when the terminal accesses the first access network device, the first access network device sends the access network tunnel information allocated to the terminal by multiple other access network devices to the AMF, thereby further improving the switching efficiency.

[0168] Alternatively, in the communication method provided by the present application, when the terminal last accesses the second access network device, the AMF receives the access network tunnel information allocated to the terminal sent by the second access network device, and stores the access network tunnel information. When the terminal accesses the second access network device next time, the second access network device no longer needs to send the access network tunnel information allocated to the terminal to the AMF, thereby further improving the switching efficiency.

[0169] In another communication method provided in an embodiment of the present application, after the AMF determines to switch the UE to the second access network device based on the second switching time information, it may not send the first message corresponding to the terminal to the SMF, but the SMF actively triggers the sending of the second message to the UPF based on the second switching time information, requesting the UPF to update the access network tunnel information of the terminal's session. Thus, the execution time of a request and response is further saved, the communication efficiency is further improved, and the communication pressure problem of the N11 interface caused by the terminal frequently executing the switching process is reduced.

[0170] In another communication method provided in an embodiment of the present application, after the SMF determines to switch the UE to the second access network device based on the second switching time information, it may not send the second message corresponding to the terminal to the UPF, but the UPF actively triggers the access network tunnel information of the session of the terminal to be updated based on the second switching time information. Thus, while alleviating the communication pressure of the NG interface and the N11 interface, the problem of communication pressure of the N4 interface caused by the terminal frequently executing the switching process is further reduced.

[0171] In this application, the N2 path switching message is also called a path switching message, the first message is also called a PDU session update request message or an update request message, and the second message is also called an N4 session modification request. The specific names depend on the communication protocol standard and are not limited in this article.

[0172] The following combination Figure 4 A communication method provided by the present application is introduced. Figure 4 For the introduction of the first access network device, the second access network device, AMF, SMF, and UPF, please refer to Figure 1-Figure 2 For details, see Figure 4 As shown, the method includes:

[0173] S401: A first access network device determines to switch a terminal to a second access network device based on first switching time information of a terminal.

[0174] The first access network device may be an access network device currently accessed by the terminal, and the first access network device may be any access network device among the access network devices that can serve the terminal.

[0175] Among them, the first switching time information corresponding to the terminal may include the time when at least one access network device serves the terminal, and the time when the access network device serves the terminal may refer to the service time period or the service end time. If the service time is the service time period, the first access network device determines to switch to the second access network device based on the end time in the service time period. If the service time is the service end time, the first access network device determines to switch the terminal to the second access network device based on the service end time. For example, when the service time is the service end time, assuming that at least one access network device includes RAN1 and RAN2, and the end time point of RAN1 serving the terminal is T1, and the end time point of RAN2 serving the terminal is T2, then the first switching time information corresponding to the terminal may include T1 corresponding to RAN1 and T2 corresponding to RAN2, which may be specifically in the form of a list without limitation.

[0176] The at least one access network device may include all or part of the access network devices capable of serving the terminal.

[0177] Among them, the access network device capable of serving the terminal refers to an access network device whose signal coverage range includes the location of the terminal during operation, and the at least one access network device includes the above-mentioned second access network device.

[0178] In some possible implementations, the satellite corresponding to the at least one access network device and the satellite corresponding to the first access network device belong to the same constellation; or, the satellite corresponding to the at least one access network device and the satellite corresponding to the first access network device have a direct and / or indirect inter-satellite link connection; or, the coverage range of each of the at least one access network device includes the location of the terminal.

[0179] In some possible implementations, the first access network device may determine the first switching time information based on the access time of the terminal to the at least one access network device in the satellite operation cycle (the previous satellite operation cycle). The satellite operation cycle refers to the period length corresponding to the satellite starting from any position on the orbit and returning to the position. The first access network device may store the access time corresponding to all or part of the access network devices that can serve the terminal accessed by the terminal in a complete satellite operation cycle. It should be noted that the access time can specifically be the service time period or the service end time. The access time and service time are just different descriptions of the same concept from different subject perspectives.

[0180] As an example, the first access network device obtains the first switching time information based on the satellite operation cycle and the access time corresponding to the terminal accessing the at least one access network device in the most recent satellite operation cycle. For example, the satellite operation cycle is 1 hour. In the satellite operation cycle, the terminal accesses RAN1 from 09:00 to 09:05, accesses RAN2 from 9:06 to 09:10, ..., then the time for the terminal to access RAN1 in the next satellite operation cycle is 10:00 to 10:05, and the time for accessing RAN2 is 10:05 to 10:10, and so on. The at least one access network device may include all or part of the access network devices accessed by the terminal in a complete satellite operation cycle. For example, the first access network device only stores the time when the terminal accesses RAN1 and RAN2 in the most recent satellite operation cycle, and does not store the time when the terminal accesses other RANs. The first switching time information can be determined according to the access time corresponding to the terminal accessing RAN1 and RAN2.

[0181] As another example, the first access network device obtains the above-mentioned first switching time information based on the satellite operation cycle and the access time corresponding to the terminal accessing the first access network device in the most recent satellite operation cycle (the access time may be the service time period of the first access network device serving the terminal, or the end time when the terminal ends accessing the first access network device). For example, the satellite operation cycle is 1 hour, and the first access network device serves the UE within 5 minutes from the start time in a satellite operation cycle. When the service end time of the first access network device serving the terminal is reached, the first access network device initiates a switching request message about the terminal to the next access network device (the second access network device) in the satellite operation direction. For example, in the most recent satellite operation cycle, the terminal accesses the first access network device from 09:00 to 09:05, then the terminal accesses the first access network device from 10:00 to 10:05 in the next satellite operation cycle of the satellite operation cycle where the first access network device is located, and in the next satellite operation cycle, the first access network device sends the switching request message to the second access network device at the end time corresponding to 10:05, and so on. Among them, the second access network device is the next access network device of the first access network device in the direction of satellite operation. The second access network device can also be determined after the first access network device interacts with multiple access network devices through inter-satellite links. There is no limitation on which access network device the second access network device is and the method of determining the second access network device.

[0182] It should be noted that the description that the satellite operation cycle is 1 hour and the duration that each access network device serves the UE for 5 minutes in one satellite operation cycle is only an example. The satellite operation cycle and the duration that each access network device serves the UE in one satellite operation cycle can also have other precisions, which is not limited in this article.

[0183] In some other possible implementations, the first access network device can determine the above-mentioned first switching time information based on the terminal's location and ephemeris information, and the ephemeris information includes the ephemeris information of the satellite corresponding to one or more access network devices that can serve the terminal. Specifically, the first access network device can calculate the location and signal coverage of the access network device corresponding to the satellite at any time in the future by mastering the ephemeris information of a certain satellite, and based on the location of the terminal and the signal coverage of the access network device, predict the access time of the terminal to each access network device, and obtain the above-mentioned first switching time information. It can be understood that the access network device corresponding to the satellite refers to the access network device deployed on the satellite.

[0184] As an example, the first access network device obtains the ephemeris information corresponding to other access network devices based on local storage and / or communication interaction with other access network devices. For example, the first access network device stores the ephemeris information corresponding to other access network devices. Alternatively, the first access network device obtains (or receives) the ephemeris information corresponding to other access network devices based on communication interaction with other access network devices. Alternatively, the first access network device obtains the ephemeris information corresponding to other access network devices based on a combination of local storage and communication interaction with other access network devices. Specifically, the first access network device locally stores the ephemeris information corresponding to some access network devices, and obtains the ephemeris information of the remaining access network devices based on communication interaction with other access network devices.

[0185] The satellite's ephemeris information includes one or more of the following: satellite coverage map, satellite coverage availability information, satellite motion law information, and satellite-related information that corresponds to time. Among them, the satellite coverage map refers to dividing the map into multiple grids, and each satellite corresponds to a coverage map at each moment. The grid points are marked on the coverage map. The bright grid points in the coverage map indicate signal coverage, and the dark grid points indicate no signal coverage. The satellite's motion law information may include information such as the satellite's orbital parameters, angular velocity, speed, and initial position. The satellite-related information that corresponds to time includes the satellite's position information and satellite capability information corresponding to the corresponding moment or time period.

[0186] In some other possible implementations, the first access network device may also obtain the first switching time information by receiving the first switching time information from the AMF. For example, the AMF determines the first switching time information based on the access time of the terminal to the at least one access network device in the satellite operation cycle, or the AMF determines the first switching time information based on the terminal's location and ephemeris information, and then sends it to the first access network device.

[0187] In some other possible implementations, the AMF may also determine the second switching time information and send the second switching time information to the first access network device. The first access network device determines the first switching time information based on the second switching time information. For details, please refer to the detailed description in step S603 below.

[0188] It should be noted that the first switching time information corresponding to the terminal stored in each access network device can be consistent. For example, the switching time information stored in each access network device includes the time when some specific access network devices in the at least one access network device serve the terminal. For another example, the switching time information stored in each access network device is the total switching time information, and the total switching time information includes the access time corresponding to the terminal accessing all access network devices that can serve the terminal, that is, the first switching time information includes the time corresponding to the at least one access network device serving the terminal, and the at least one access network device is the terminal accessing all access network devices that can serve the terminal. In this scenario, after obtaining the above-mentioned first switching time information, the first access network device can also send the first switching time information to other access network devices that can serve the terminal, so as to further improve the performance loss problem caused by other access network devices mechanically and repeatedly determining the switching time information corresponding to the terminal.

[0189] Alternatively, the first switching time information stored in each access network device and the terminal may also be inconsistent. For example, the first switching time information stored in the first access network device only includes one of the access time (time point or time period) when the terminal accesses the adjacent access network device, the time period when the terminal accesses the first access network device, and the end time when the terminal ends the connection with the first access network device, wherein the adjacent access network device is the next access network device of the first access network device in the satellite operation direction.

[0190] In some possible implementations, the communication method provided in the present application is applicable to a scenario in which a terminal belonging to a target terminal type executes a switching process, and the terminal of the target terminal type is a stationary terminal. As an example, a stationary terminal refers to a terminal whose position does not change or whose moving speed is 0. It should be noted that the communication method provided in the present application is also applicable to a scenario in which a terminal whose type does not belong to the target terminal type executes a switching process, but in this scenario, when the position of the terminal changes, the access network device and the AMF side need to re-acquire the corresponding switching time information according to the position of the terminal.

[0191] S402: The first access network device sends a switching request message corresponding to the terminal to the second access network device.

[0192] Correspondingly, the second access network device receives the switching request message.

[0193] The handover request message is used to request that the terminal be handed over to the second access network device. Exemplarily, the handover request message carries the context information of the terminal, and the context information of the terminal includes the first identifier of the terminal. In some possible implementations, the context information may also include the identifier of the PDU session of the terminal. The first identifier of the terminal may be the identifier of the terminal (UE ID), or the first identifier of the terminal may also be the cell radio network temporary identifier (C-RNTI) of the terminal.

[0194] S403: The second access network device communicates with the user plane function network element based on the switching request message and the core network tunnel information of the terminal stored in the second access network device.

[0195] Exemplarily, in response to the switching request message, the second access network device triggers the establishment of a GTP-U tunnel for communication with the user plane function network element through the core network tunnel information of the terminal stored in the second access network device.

[0196] In a possible implementation, before the second access network device receives the handover request message from the first access network device, the second access network device also includes: receiving the core network tunnel information of the terminal and storing the core network tunnel information. The second access network device receives the core network tunnel information corresponding to the terminal, including: receiving the core network tunnel information of the terminal from the first access network device; or receiving the core network tunnel information of the terminal from the session management function network element.

[0197] That is to say, Figure 5A As shown, the core network tunnel information of the terminal stored in the second access network device may come from the third access network device (the third access network device is the first access network device or other access network devices). Specifically, the access network tunnel information of the terminal may be that when the terminal accesses the third access network device in the previous satellite operation cycle, the third access network device requests the UPF to allocate core network tunnel information for other access network device service terminals, the other access network devices include the second access network device, and the other access network devices include the second access network device; after the UPF allocates the corresponding core network tunnel information for the other access network device service terminal, it sends it to the corresponding access network device in the other access network devices through the third access network device, and after the other access network devices receive the corresponding core network tunnel information, they store the corresponding core network tunnel information.

[0198] Or, reuse Figure 5A, the core network tunnel information of the terminal stored in the second access network device may also come from SMF. Specifically, the core network tunnel information of the terminal is allocated by UPF to the second access network device to serve the terminal when the terminal accesses the second access network device in the historical satellite operation cycle and sent to the second access network device through SMF. For example, before receiving the above-mentioned switching request message, when the terminal accesses the second access network device in the previous satellite operation cycle, the second access network device sends a path switching message to AMF, so that UPF is requested to allocate core network tunnel information to the terminal through AMF and SMF; after UPF allocates core network tunnel information to the terminal, it sends it to the second access network device, and after the second access network device receives the core network tunnel information, it stores the core network tunnel information.

[0199] In the embodiment of the present application, after the second access network device receives the switching request message of the terminal, the second access network device does not send a path switching message to the AMF requesting the UPF to allocate core network tunnel information to the terminal, but communicates with the terminal based on the core network tunnel of the terminal established between the second access network device and the UPF. As a result, the process of the second access network device requesting and waiting for the UPF to allocate core network tunnel information to the terminal in the switching process is omitted, the switching efficiency is improved, and the problem of network congestion caused by multiple terminals frequently executing the switching process is avoided.

[0200] S404: AMF determines to switch the terminal to the second access network device based on the second switching time information corresponding to the terminal.

[0201] In an embodiment of the present application, the second switching time information includes the time when at least one access network device serves the terminal, the at least one access network device includes a second access network device, and the at least one access network device includes all or part of the access network devices that can serve the terminal.

[0202] In an embodiment of the present application, the first switching time information stored in the first access network device corresponds to the second switching time information stored in the AMF.

[0203] As an example, for the time when the same access network device (for example, access network device A) serves the terminal, the time when the access network device A serves the terminal recorded in the first switching time information is the same as the time when the access network device A serves the terminal recorded in the second switching time information.

[0204] As another example, for the access time corresponding to the same access network device (e.g., access network device A), the time recorded in the first switching time information for the access network device A to serve the terminal is earlier or later than the time recorded in the second switching time information for the access network device A to serve the terminal. For example, the time recorded in the first switching time information for the access network device A to serve the terminal is recorded as 1, and the time recorded in the second switching time information for the access network device A to serve the terminal is recorded as service time 2, and the service time 1 is earlier than the service time 2. For example, the time difference between the two service times is the time of a satellite-to-ground transmission signaling, that is, although the second access network device does not send a signaling of a path switching message to the AMF, since the AMF needs to wait for the sending of the signaling when normally executing the switching process of the terminal switching to the second access network device to trigger the execution of the corresponding switching process, the time period of signaling transmission is within an acceptable error range, wherein the time difference between the two service times, the early and late of the two service times, and the length of the time difference are not limited in this article.

[0205] In some possible implementations, the AMF determines the second switching time information based on the access time of the terminal to at least one access network device in the satellite operation cycle. For details, please refer to the above description of the first access network device determining the first switching time information based on the access time of the terminal to at least one access network device in the satellite operation cycle, which will not be described in detail here.

[0206] In some other possible implementations, the AMF determines the second switching time information based on the location and ephemeris information of the terminal. Specifically, the AMF can obtain the ephemeris information based on the local configuration and / or the communication interaction with the access network device to determine the second switching time information, for example, by communicating and interacting with the access network device through the NG Set Request message to obtain the corresponding ephemeris information. For details, please refer to the above description of the determination of the first switching time information by the first access network device based on the location and ephemeris information of the terminal, which will not be described in detail here.

[0207] In some other possible implementations, the AMF may also obtain the second switching time information based on the switching time information (first switching time information or second switching time information) from any access network device that can serve the terminal.

[0208] S405, AMF sends the first message corresponding to the terminal to SMF.

[0209] Accordingly, the SMF receives the first message.

[0210] The first message is used to update the access network tunnel information of the terminal.

[0211] Specifically, the first message can be used to request the SMF to update the access network tunnel information of the terminal session to the access network tunnel information corresponding to the second access network device.

[0212] In an embodiment of the present application, the AMF determines that the target access network device corresponding to the terminal and the current time in the second switching time information is the second access network device, and triggers the sending of the above-mentioned first message to the SMF, and the first message includes a request message for requesting the SMF to update the access network tunnel information of the terminal's session to the access network tunnel information corresponding to the second access network device. In some descriptions of the present application, the first message may also be referred to as an update request message (e.g., Nsmf_PDUsession_Update SMContext Request), and the specific name of the first message depends on the protocol standard, which is not limited in this document.

[0213] Reference Figure 5B In some possible implementations, the access network tunnel of the second access network device serving the terminal may be allocated by SMF; accordingly, the first message sent by AMF to SMF may carry the identifier of the second access network device, and the first message is used to request SMF to allocate the first access network tunnel information to the terminal based on the identifier of the second access network device, and request SMF to update the access network tunnel information of the terminal to the first access network tunnel information.

[0214] Reference Figure 5B In some possible implementations, the access network tunnel of the second access network device serving the terminal may also be allocated by the second access network device. After the second access network device allocates access network tunnel information to the terminal, it sends the access network tunnel information to the AMF, and the AMF determines the data content carried in the above-mentioned first message based on the access network tunnel information. For example, when the terminal accesses the second access network device in the previous satellite operation cycle, the second access network device sends the access network tunnel information allocated to the terminal to the AMF through a path switching message, and the corresponding AMF stores the access network tunnel information, the identifier of the second access network device, the identifier of the terminal, and the access time of the next access of the terminal to the second access network device, so that in the next satellite operation cycle, when the terminal accesses the second access network device again, the AMF actively triggers the sending of the first message to the SMF based on the identifier of the corresponding second access network device and the access network tunnel information based on the access network tunnel information in the association relationship and the access time of the next access of the terminal to the second access network device.

[0215] Regarding the method for sending the access network tunnel information allocated by the second access network device to the terminal to the AMF, please refer to the relevant instructions on method 1 and method 2 below, which will not be described in detail here.

[0216] It should be noted that regardless of whether the access network tunnel information of the service terminal is allocated by the SMF or by the second access network device, the access network tunnel information can be access network tunnel information of session granularity, slice granularity, UE-RAN granularity, or RAN granularity.

[0217] As an example, the access network tunnel information allocated by the second access network device to the terminal belongs to the aggregated access network tunnel information of UE-RAN granularity or RAN granularity, and the above-mentioned first message carries the identifier of the second access network device and the identifier of one or more sessions of the terminal. The first message is used to request the SMF to determine the aggregated access network tunnel information corresponding to the identifier of the second access network device, and update the access network tunnel information corresponding to the one or more sessions of the terminal to the aggregated access network tunnel information. For example, before the second access network device receives the switching request message corresponding to the terminal from the first access network device, the second access network device has sent the aggregated access network tunnel information of UE-RAN granularity or RAN granularity to the AMF, and after the AMF receives the aggregated access network tunnel information, it sends the correspondence between the aggregated access network tunnel information and the identifier of one or more sessions of the terminal to the SMF, and the SMF records the correspondence between the aggregated access network tunnel information and the identifier of one or more sessions of the terminal. Therefore, after receiving the first message from AMF carrying the identifier of the second access network device and the identifier of one or more sessions of the terminal, SMF can determine the aggregated access network tunnel information corresponding to the identifier of the second access network device, and based on the aggregated access network tunnel information, update the access network tunnel information corresponding to the one or more sessions of the terminal to the aggregated access network tunnel information.

[0218] As another example, the access network tunnel information allocated by the second access network device to the terminal belongs to the access network tunnel information with session granularity. The above-mentioned first message carries the identifiers of one or more sessions of the terminal and the access network tunnel information corresponding to the one or more sessions. The first message is used to request the SMF to update the access network tunnel information of the corresponding session in the terminal to the access network tunnel information of the second access network device serving the session.

[0219] Using the communication method provided by the present application, in the Xn switching process of the terminal, the second access network device communicates with the UPF based on the core network tunnel information stored in the second access network device, and does not need to send a path switching message to the AMF to request the UPF to allocate the core network tunnel information to the terminal, thereby alleviating the communication pressure of the NG interface and improving the switching efficiency. In addition, the first access network device and the AMF respectively perform corresponding tasks regarding the UE switching to the second access network device based on the first switching time information and the second switching time information, thereby ensuring the consistency and integrity of the switching process of the UE switching from the first access network device to the second access network device.

[0220] S406, SMF sends the second message corresponding to the terminal to UPF.

[0221] Among them, the second message is used to request UPF to update the access network tunnel information corresponding to the terminal to the access network tunnel information corresponding to the second access network device.

[0222] Accordingly, the UPF receives the second message.

[0223] In an embodiment of the present application, the second message may also be referred to as an N4 session modification request, and the second message carries the access network tunnel information of the terminal, and does not carry the indication information requesting the UPF to allocate the core network tunnel information of the terminal. Exemplarily, the second message specifically carries the first N4session ID and the second access network tunnel information, the first N4 session ID corresponds to one or more sessions of the terminal, and the first N4 sessionID is a private identifier between the SMF and the UPF that identifies one or more sessions of the same terminal. Based on the second message, the UPF modifies the access network tunnel information corresponding to the first N4 session ID to the second access network tunnel information.

[0224] In a possible implementation, after the second access network device receives the handover request message from the first access network device in step S402, Figure 4 The communication method shown also includes: if the second access network device has stored the core network tunnel information of the terminal and the second access network device has allocated the access network tunnel information to the terminal, the second access network device does not send a path switching message to the access and mobility management function network element, and the path switching message is used to switch the path corresponding to the terminal.

[0225] In the embodiments of the present application, Figure 5B As shown, the access network tunnel information of the UPF and the second access network device serving the terminal can be allocated by the second access network device to the terminal, and can be sent to the AMF through two optional methods (method 1 and method 2) before the second access network device receives the above-mentioned switching request message corresponding to the terminal.

[0226] Method 1: The access tunnel information allocated by the second access network device to the terminal is sent to the AMF through a path switching message in the previous satellite operation cycle.

[0227] Exemplarily, before the second access network device receives the switching request message corresponding to the terminal, the terminal has accessed the second access network device in the previous satellite operation cycle, and the second access network device has sent a path switching message to the AMF carrying the access network tunnel information allocated by the second access network device to the terminal.

[0228] Method 2: The access network tunnel information allocated by the second access network device to the terminal is sent to the AMF through the third access network device.

[0229] The third access network device may be the first access network device or other access network devices.

[0230] Exemplarily, before the first access network device sends a switching request message to the second access network device, the first access network device requests other access network devices to allocate access network tunnel information for the terminal, and the other access network devices include the second access network device; the first access network device receives the access network tunnel information allocated by the other access network device to the terminal, and sends the access network tunnel information allocated by the other access network device to the terminal to the AMF. Thus, when the terminal accesses the second access network device, the second access network device and the UPF use the access network tunnel information allocated by the second access network device to the terminal in advance to serve the terminal, so that the second access network device does not need to send a path switching message carrying the access network tunnel information allocated by the second access network device to the terminal to the AMF. In an embodiment of the present application, when at least one access network device in the above-mentioned first switching time information includes the first access network device, the other access network devices include one or more access network devices other than the first access network device in the at least one access network device; when the above-mentioned at least one access network device does not include the first access network device, the other access network device is one or more of the at least one access network device.

[0231] Based on method 1 or method 2, when the terminal accesses the second access network device again, the AMF or SMF requests the UPF to update the N3 path of the terminal based on the access network tunnel information allocated by the second access network device in the previous satellite operation cycle of the terminal, or based on the access network tunnel information allocated by the second access network device to the terminal in advance before receiving the above-mentioned switching request message. The second access network device no longer needs to send the access network tunnel information allocated by the second access network device to the terminal to the AMF through the NG interface, thereby further improving the signaling storm problem of the NG interface, alleviating the communication pressure of the NG interface, and improving the switching efficiency.

[0232] Among them, in the above-mentioned method 1, the second access network device only needs to send the access network tunnel information allocated by the second access network device to the terminal to AMF once. When the terminal accesses the second access network device next time, the second access network device will no longer send tunnel information to the terminal. Sending once is used for multiple times, which relieves the communication pressure of the NG interface and improves the switching efficiency. For example, the signaling interaction about the access network tunnel information between the second access network device corresponding to the terminal accessing the same second access network device n times (n is greater than or equal to 2) and AMF is reduced from n signaling to one, which relieves the communication pressure of the NG interface; in addition, the access network tunnel information allocated by the second access network device to the terminal does not need to be forwarded to AMF through the third access network device, which reduces the interaction between access network devices.

[0233] In the above-mentioned method 2, the third access network device forwards the access network tunnel information allocated by other access network devices to the terminal to the AMF. For example, the other access network devices are all or part of the access network devices that can serve the terminal except the third access network device. That is to say, the signaling interaction of all the access network devices (or the part of the access network devices) to send the access network tunnel information to the AMF is merged into the same message and sent. All the access network devices (including the second access network device) can send the signaling containing the access network tunnel information to the AMF without going through the NG interface from beginning to end, which further alleviates the communication pressure of the NG interface and improves the switching efficiency.

[0234] In an embodiment of the present application, the access network tunnel information and core network tunnel information of the terminal may be tunnel information at a session granularity, a slice granularity, a UE-RAN granularity, or a RAN granularity.

[0235] In some possible implementations, when the access network tunnel information allocated by the second access network device to the terminal belongs to the access network tunnel of the session granularity, the above-mentioned first access network device requests other access network devices to allocate access network tunnel information for the terminal, which may specifically include: in the process of the terminal establishing the first session through the first access network device, the first access network device requests other access network devices to allocate access network tunnel information for the first session, and the request may carry the identifier of the first session. Exemplarily, the terminal establishes session 1 and session 2 through the first access network device, then in the process of establishing session 1 and session 2, the first access network device may request other access network devices to allocate access network tunnel information for the session 1 and session 2, wherein request 1 (requesting the other access network device to allocate access network tunnel information for session 1) and request 2 (requesting the other access network device to allocate access network tunnel information for session 2) may be in the same message, or may be two different request messages, which is not limited in this document.

[0236] For the above-mentioned method 2, after the terminal accesses each access network device, it is not necessary for the access network device to request other access network devices to allocate access network tunnel information to the terminal. Exemplarily, when the first access network device accessed by the terminal belongs to a preset access network device, the first access network device requests other access network devices to allocate access network tunnel information to the terminal. The preset access network device is a preset access network device for requesting other access network devices to allocate access network tunnel information to the terminal. For example, the preset access network device is the first access network device accessed by the terminal, or the preset access network device is a specific access network device at a specific position in the satellite operation cycle, or the preset access network device is an access network device for establishing a session with the terminal.

[0237] In some other possible implementations, if the second access network device does not store the core network tunnel information of the terminal, or the second access network device does not allocate access network tunnel information to the terminal, a path switching message is sent to the access and mobility management function network element, and the path switching message is used to switch the path corresponding to the terminal.

[0238] Exemplarily, after receiving the switching request message in step S802, the second access network device determines whether the second access network device stores the core network tunnel information of the terminal, and determines whether the second access network device has allocated the access network tunnel information to the terminal.

[0239] Among them, 1) when the second access network device determines that the core network tunnel information of the terminal is not stored and the second access network device has not allocated the access network tunnel information to the terminal, it sends a path switching message to the AMF, thereby requesting the UPF to allocate the core network tunnel information to the terminal through the AMF and SMF, and receiving the access network tunnel information allocated by the second access network device to the terminal and sending it to the UPF. For example, after the second access network device requests the UPF to allocate the core network tunnel information to the terminal through the AMF and SMF, the second access network device allocates the access network tunnel information to the terminal and sends it to the UPF through the AMF and SMF.

[0240] 2) When the second access network device determines that the core network tunnel information of the terminal is not stored and the second access network device has allocated the access network tunnel information to the terminal, it sends a path switching message to the AMF, so that it requests the UPF to allocate the core network tunnel information to the terminal through the AMF and SMF. After the second access network device receives the core network tunnel information of the terminal, the second access network device may send or not send the access network tunnel information allocated by the second access network device to the terminal to the UPF, which is not limited in this document.

[0241] 3) When the second access network device determines that the core network tunnel information of the terminal is stored and the second access network device has not allocated the access network tunnel information to the terminal, the second access network device sends a path switching message to the AMF, and the second access network device may also perform step S403. As an example, the path switching message may carry the access network tunnel information allocated by the second access network device to the terminal, and the path switching message is used to instruct the AMF to request the SMF to request the UPF to update the access network tunnel information of the terminal. The relationship between the path switching message and the core network tunnel information is described below: When the second access network device does not perform step S403, the path switching message may also be used to request the UPF to allocate new core network tunnel information to the terminal, or, when the second access network device performs step S403, the path switching message may not have the function of requesting the UPF to allocate new core network tunnel information to the terminal, which is not limited in this document. As another example, the path switching message does not carry the access network tunnel information allocated by the second access network device to the terminal. The path switching message is used to request the UPF to allocate new core network tunnel information to the terminal, and enable the second access network device to allocate access network tunnel information to the terminal and send it to the UPF after receiving the core network tunnel information of the terminal. The second access network device and the UPF communicate based on the new core network tunnel information of the terminal and the access network tunnel information of the terminal).

[0242] 4) When the second access network device determines that the core network tunnel information of the terminal has been stored and the second access network device has allocated the access network tunnel information to the terminal, it does not send a path switching message to the AMF. Thus, the relevant request and waiting time are omitted, the switching efficiency of the terminal frequently executing the switching process is improved, and the communication pressure of the NG interface caused by the terminal frequently executing the switching process is improved.

[0243] In some other possible implementations, the access network tunnel information of the terminal served by the second access network device is allocated by SMF. Then, after receiving the switching request message in step S802, the second access network device determines whether the second access network device stores the core network tunnel information of the terminal, without determining whether the second access network device has allocated the access network tunnel information for the terminal. And if it is determined that the second access network device has stored the core network tunnel information of the terminal, the second access network device executes S403. If it is determined that the second access network device does not store the core network tunnel information of the terminal, the second access network device sends a path switching message to AMF, so that it requests UPF to allocate the core network tunnel information for the terminal through AMF and SMF.

[0244] In some other possible implementations, the path switching message may also carry a terminal identifier assigned by the second access network device to the terminal. The above "if the second access network device has stored the core network tunnel information of the terminal, and the second access network device has allocated the access network tunnel information to the terminal, the second access network device does not send a path switching message to the access and mobility management function network element" specifically includes: when the second access network device has stored the core network tunnel information of the terminal, and the second access network device has allocated the access network tunnel information to the terminal, and the second access network device has allocated the terminal identifier to the terminal, the second access network device does not send a path switching message to the AMF.

[0245] In addition, the above-mentioned "if the second access network device does not store the core network tunnel information of the terminal, or the second access network device does not allocate access network tunnel information to the terminal, a path switching message is sent to the access and mobility management function network element, and the path switching message is used to switch the path corresponding to the terminal" specifically includes: when the second access network device does not store the core network tunnel information of the terminal, or the second access network device does not allocate access network tunnel information to the terminal, or the second access network device does not allocate a terminal identifier to the terminal, a path switching message is not sent to the AMF.

[0246] Accordingly, in some possible implementations, in step S404, AMF determines that switching the terminal to the second access network device may specifically include: AMF determines the target access network device corresponding to the terminal and the current time in the second switching time information as the second access network device, and updates the second identifier of the terminal recorded locally to the terminal identifier assigned to the terminal by the second access network device, where the second identifier is a private terminal identifier (also called RAN UE NGAP ID) used to identify the terminal between the AMF and the access network device to which the terminal accesses.

[0247] In some possible implementations, such as Figure 5C As shown, the terminal identifier allocated by the second access network device to the terminal can be sent in advance to the AMF in the following two optional ways (way 3 and way 4). Here, "in advance" means before the second access network device receives the above-mentioned switching request message corresponding to the terminal, or before the AMF determines that the terminal switches to the second access network device based on the second switching time information.

[0248] Method 3: During the previous satellite operation cycle, the second access network device sends the terminal identifier allocated to the terminal by the second access network device to the AMF through a path switching message.

[0249] Exemplarily, before the second access network device receives the switching request message from the first access network device in step S402, the terminal has accessed the second access network device in a previous satellite operation cycle, and the second access network device has sent a path switching message carrying the terminal identifier assigned to the terminal by the second access network device to the AMF in any satellite operation cycle of the previous satellite operation cycle (for example, when the terminal accessed the second access network device for the first time or the last time).

[0250] Method 4: Before the terminal accesses the second access network device (that is, before the second access network device receives the above-mentioned switching request message), the terminal identifier allocated to the terminal by the second access network device is sent to AMF through the third access network device. The third access network device can be the first access network device or other access network device.

[0251] Exemplarily, before the first access network device sends a switching request message to the second access network device, the first access network device requests other access network devices to allocate a terminal identifier for the terminal, the other access network devices include the second access network device, and the other access network devices include all access network devices or part of the access network devices that can serve the terminal; the first access network device receives the terminal identifier allocated to the terminal by the other access network device, and sends the terminal identifier allocated to the terminal by the other access network device to the AMF.

[0252] It should be noted that, for the above-mentioned method 4, it is not necessary for the access network device to request other access network devices to allocate a terminal identifier for the terminal after the terminal accesses each access network device. Exemplarily, when the first access network device accessed by the terminal belongs to a preset access network device, the first access network device requests other access network devices to allocate a terminal identifier for the terminal. The preset access network device is a preset access network device for requesting other access network devices to allocate a terminal identifier for the terminal. For example, the preset access network device is the first access network device accessed by the terminal, or the preset access network device is a specific access network device at a specific position in the satellite operation cycle.

[0253] Using the communication method provided in the present application, the first access network device sends a switching request message to the second access network device based on the first switching time information. After receiving the switching request message, the second access network device communicates with the UPF based on the stored core network tunnel information of the terminal. The AMF actively triggers the execution of corresponding tasks regarding the UE switching to the second access network device based on the second switching time information (including sending a first message to the SMF to request to update the access network tunnel information of the terminal and update the second identifier of the terminal), thereby ensuring the consistency and integrity of the air interface switching, the update of the RAN UE NGAP ID, and the N3 path update (including the update of the access network tunnel information and the core network tunnel information) in the switching process of the UE switching from the first access network device to the second access network device.

[0254] In some other possible implementations, the first access network device may also send a switching request message about the terminal to the second access network device based on the change in signal strength, without determining to send a switching request message about the terminal to the second access network device based on the first switching time information. And the service time corresponding to each access network device included in the above second switching time information corresponds to the request time when the first access network device sends a switching request message of the terminal to the corresponding access network device based on the change in signal strength. For example, the service time of the second access network device serving the terminal in the second switching time information corresponds to the request time corresponding to the switching request message about the terminal sent by the first access network device to the second access network device based on the change in signal strength; the service time of the third access network device serving the terminal in the second switching time information corresponds to the request time corresponding to the switching request message about the terminal sent by the second access network device to the third access network device based on the change in signal strength. In addition, the terminal is a stationary terminal, so even if the source access network device does not send a switching request message of the terminal to the target access network device based on the first switching time information but based on the change in signal strength, it can also execute the relevant processes related to the terminal switching to the target access network device synchronously with the AMF to ensure the consistency and integrity of the switching process.

[0255] The following is based on the distribution subject of the access network tunnel information used by the second access network device to serve the terminal, the diversity of the tunnel information (core network tunnel information and access network tunnel information) service granularity, combined with Figures 6 to 11 Introduce the specific application of the communication method provided by this application.

[0256] The following combination Figure 6 The interaction diagram shown in the figure introduces an application of the communication method provided in the embodiment of the present application by taking the second access network device allocating access network tunnel information to the terminal and sending the access network tunnel information allocated by the second access network device to the AMF through the above-mentioned method 1 as an example. Figure 6 As shown, the method comprises the following steps:

[0257] S601, AMF determines the second switching time information corresponding to the terminal.

[0258] In an embodiment of the present application, the second switching time information corresponds to the terminal (UE), and different UEs correspond to different switching time information. The second switching time information includes an identifier of at least one access network device and a time corresponding to the identifier of the access network device for serving the terminal, and in the second switching time information, there may be one or more service times corresponding to the identifier of the same access network device.

[0259] In an embodiment of the present application, the AMF may determine the second switching time information based on the access time corresponding to the terminal accessing at least one access network device in the satellite operation cycle, or determine the second switching time information based on the terminal's position and ephemeris information. Regarding how to determine the second switching time information based on the terminal's position and ephemeris information, the specific determination method may refer to the relevant description in step S404 above.

[0260] As an example, the trigger condition for AMF to determine the second switching time information of the terminal may be that AMF receives a session establishment request from the terminal to establish a first session.

[0261] As another example, the trigger condition for AMF to update (determine) the second switching time information of the terminal may be that the latest service time contained in the second switching time information corresponding to the terminal is later than the current time, and the difference between the latest service time and the current time is less than a preset duration.

[0262] As another example, the trigger condition for AMF to update (determine) the second switching time information of the terminal may also be that AMF completes a switching task of the terminal each time.

[0263] It should be noted that the AMF may also determine or update the second switching time information of the terminal based on other appropriate triggering conditions, which is not limited in this document.

[0264] As an example, if the AMF updates the second switching time information of the terminal once after executing a switching task of the terminal, the second switching time information determined by the AMF once corresponds to the target access network device that the terminal will access next, that is, the at least one access network device is the target access network device that the terminal will access next in the direction of satellite operation.

[0265] As another example, the second switching time information determined by the AMF at one time corresponds to at least two access network devices, and the at least two access network devices may be access network devices arranged in sequence with the access network device currently accessed by the terminal in the direction of satellite operation.

[0266] In the embodiment of the present application, the service time of the access network device serving the terminal can be a time or a service time period, which is not limited in this document. When the service time is a service time period, the switching time when the terminal switches from the first access network device to the second access network device is the end time of the service time period corresponding to the first access network device, or the start time of the service time period corresponding to the second access network device.

[0267] Exemplarily, taking the service time as the service time period and the identifier of the same access network device corresponding to two different service times as an example, the data specifically included in the second switching time information may be as shown in Table 1 below.

[0268] Table 1

[0269]

[0270] S602, AMF sends second switching time information to the first access network device.

[0271] Correspondingly, the first access network device receives the second switching time information sent by the AMF.

[0272] S603: The first access network device determines first switching time information based on the second switching time information.

[0273] Exemplarily, after determining the second switching time information, the AMF may send the second switching time information to the first access network device, and the first access network device determines the first switching time information based on the second switching time information. The service time of the access network device service terminal included in the first switching time information corresponds one-to-one to the service time of the access network device service terminal included in the second switching time information.

[0274] As an example, for the same access network device A, the service time corresponding to the access network device A in the first switching time information is one millisecond earlier than the service time corresponding to the access network device A in the second switching time. After receiving the first switching time information, the first access network device can determine the first switching time information based on the second switching time information and the first millisecond, and the first millisecond can be the time for a satellite-to-ground transmission signaling.

[0275] S604: The first access network device sends a switching request message corresponding to the terminal to the second access network device based on the first switching time information corresponding to the terminal.

[0276] Correspondingly, the second access network device receives the switching request message.

[0277] In an embodiment of the present application, the first access network device determines to switch the terminal to the second access network device based on the first switching time information corresponding to the terminal, and sends a switching request message corresponding to the terminal to the second access network device.

[0278] As an example, the handover request message carries the context information of the terminal, and the context information of the terminal includes a first identifier of the terminal. Exemplarily, the first identifier may be a C-RNTI of the terminal.

[0279] S605: The second access network device determines whether the core network tunnel information of the terminal is stored.

[0280] In an embodiment of the present application, the core network tunnel information may be a session granularity, a slice granularity, a UE-RAN granularity or a RAN granularity, which is not limited in this document.

[0281] In an embodiment of the present application, when the core network tunnel information is UE-RAN granularity or RAN granularity, the second access network device executes step S606 when it is determined that the core network tunnel information of the terminal is not stored; the second access network device executes step S609 when it is determined that the core network tunnel information of the terminal is stored.

[0282] When the core network tunnel information is of session granularity, the second access network device determines in step S605 whether the core network tunnel information of the terminal has been stored, including: the second access network device determines whether the core network tunnel information corresponding to all sessions of the terminal has been stored. If the second access network device determines that the core network tunnel information corresponding to all sessions of the terminal has been stored, the second access network device executes step S606; if the second access network device determines that the core network tunnel information corresponding to all sessions of the terminal has not been stored, the second access network device executes step S609.

[0283] When the core network tunnel information is at a slice granularity, the second access network device determines in step S605 whether the core network tunnel information of the terminal has been stored, including: the second access network device determines whether the core network tunnel information corresponding to all slices of the terminal has been stored. If the second access network device determines that the core network tunnel information corresponding to all slices of the terminal has been stored, the second access network device executes step S606. If the second access network device determines that the core network tunnel information corresponding to all slices of the terminal has not been stored, the second access network device executes step S609.

[0284] S606, the second access network device sends a path switching message to the AMF.

[0285] Correspondingly, AMF requests UPF to allocate the core network tunnel information of the terminal based on the path switching request.

[0286] As an example, the step S606 specifically includes: the second access network device sends a path switching message to AMF, the path switching message is used to instruct (or trigger) AMF to request core network tunnel information from UPF through SMF; AMF responds to the path switching message, sends an update request message to SMF, the update request message carries instruction information for instructing SMF to request UPF to allocate core network tunnel information for the terminal; SMF responds to the update request message and sends an N4 session modification request to UPF, the N4 session modification request includes information for instructing UPF to allocate core network tunnel information for the terminal. The specific implementation of step S606 can also refer to the protocol standard 3GPP TS 23.502, the above-mentioned path switching message can also carry the terminal identifier (UEID) and the terminal identifier (RAN UE NGAP ID) assigned by the second access network device to the terminal, so that AMF updates the second identifier corresponding to the terminal to the terminal identifier assigned by the second access network device to the terminal, and the second identifier is a private terminal identifier (also called RAN UE NGAP ID) that identifies the terminal between AMF and the access network device to which the terminal switches.

[0287] Exemplarily, AMF can store a first correspondence based on the terminal identifier assigned to the terminal by the second access network device carried in the path switching message, and the first correspondence includes the identifier of the terminal, the identifier of the access network device, and the correspondence between the terminal identifier assigned to the terminal by the access network device. For example, the data contained in the first correspondence is shown in Table 2 below. Based on the first correspondence, when the terminal accesses the second access network device next time, AMF can actively trigger the update of the second identifier corresponding to the terminal based on the first switching time information and the first correspondence, without relying on the path switching request message sent by the second access network device to trigger.

[0288] Table 2

[0289]

[0290]

[0291] In some other possible implementations, the above-mentioned path switching message may not include the terminal identifier assigned by the second access network device to the terminal, but as shown in the above method 4, before the terminal accesses the second access network device, the terminal identifier assigned by the second access network device to the terminal is sent to the AMF through the third access network device.

[0292] In an embodiment of the present application, the UPF corresponding to the second access network device may be the same as or different from the UPF corresponding to the first access network device, and this document does not limit this.

[0293] S607, UPF sends the core network tunnel information allocated to the terminal to the second access network device.

[0294] Specifically, UPF can send the core network tunnel information corresponding to the second access network device and the terminal to the second access network device through AMF and SMF, or UPF can also send the core network tunnel information corresponding to the second access network device and the terminal to the first access network device through AMF and SMF, and then the second access network device sends the core network tunnel information allocated by UPF to the second access network device and the terminal to the first access network device. This document does not limit this.

[0295] In an embodiment of the present application, after receiving the core network tunnel information of the terminal, the second access network device stores the core network tunnel information of the terminal. Exemplarily, the second access network device stores the second corresponding relationship shown in Table 3 below, which includes the corresponding relationship between the terminal identifier and the core network tunnel information. Thus, the second access network device can determine not to send a path switching message to the AMF based on the second corresponding relationship in step S609.

[0296] Table 3

[0297] Terminal identification Core network tunnel information UE1 ID CN tunnel info1 UE2 ID CN tunnel info2 .... …… UE3 ID CN tunnel info3 .... ……

[0298] S608, send the access network tunnel information of the terminal allocated by the second access network device to SMF and UPF through AMF.

[0299] For details, please refer to the description of the relevant switching process in the standard 3GPP TS23.502.

[0300] In some other possible implementations, the second access network device may also send the access network tunnel information allocated by the second access network device to the terminal to the UPF in step S606, and omit step S608. Specifically, the access network tunnel information allocated by the second access network device to the terminal is carried in the path switching message, update request message, and N4 session modification request in S606.

[0301] After receiving the access network tunnel information sent by the second access network device through the AMF, the SMF can store the correspondence between the terminal identifier, the second access network device identifier, and the access network tunnel information allocated by the second access network device to the terminal, and obtain a third correspondence, which includes the correspondence between the terminal identifier, the access network device identifier, and the access network tunnel information. Exemplarily, when the access network tunnel information is aggregated access network tunnel information at the UE-RAN granularity, the data included in the third correspondence is shown in Table 4 below. When the access network tunnel information is aggregated access network tunnel information at the RAN granularity, the data included in the third correspondence is shown in Table 5 below.

[0302] Based on the third correspondence, and in combination with the correspondence between the identifiers of all sessions of the terminal stored in the SMF and the identifier of the terminal, when the terminal accesses the second access network device next time, the SMF receives an update request message from the AMF carrying the identifier of the terminal and the identifier of the second access network device, the SMF can, based on the third correspondence, update the access network tunnel information of all sessions corresponding to the terminal to the access network tunnel information allocated to the terminal by the second access network device.

[0303] Table 4

[0304]

[0305]

[0306] Table 5

[0307] Terminal identification Identification of access network equipment Aggregate access network tunnel information UE1 ID, UE2 ID, UE3 ID, UE4 ID,... RAN1 ID AN tunnel info1 UE5 ID, UE6 ID, UE7 ID, UE8 ID,... RAN2 ID AN tunnel info2 …… …… ……

[0308] As another example, after receiving the access network tunnel information sent by the second access network device through AMF, SMF may also store the correspondence between the identifiers of one or more sessions, the identifier of the second access network device, and the access network tunnel information allocated by the second access network device to the terminal, to obtain a fourth correspondence. Exemplarily, the data contained in the fourth correspondence is shown in Table 6 below, and the fourth correspondence includes the identifier of the session, the identifier of the access network device, and the correspondence between the aggregated access network tunnel information. Based on this, when the terminal accesses the second access network device next time, when SMF receives an update request message from AMF carrying the identifiers of one or more sessions and the identifier of the second access network device, SMF can update the access network tunnel information of the corresponding one or more sessions to the aggregated access network tunnel information allocated by the second access network device to the terminal based on the fourth correspondence.

[0309] Table 6

[0310]

[0311] S609: Based on the core network tunnel information of the terminal stored therein, the second access network device determines not to send a path switching message to the AMF.

[0312] In an embodiment of the present application, when the second access network device determines that the core network tunnel information of the terminal has been stored, it does not send a path switching message to the AMF, thereby improving the signaling storm problem of the NG interface and improving the switching efficiency.

[0313] S610, AMF determines to switch the terminal to the second access network device based on the second switching time information.

[0314] As an example, the AMF determines to switch the terminal to the second access network device based on the second switching time information, specifically including: the AMF determines that the identifier of the target access network device of the terminal corresponding to the current time is the identifier of the second access network device based on the second switching time information shown in Table 1 above. And, based on the first corresponding relationship shown in Table 2 above, the terminal identifier assigned to the terminal by the second access network device is determined, and the second identifier of the terminal stored locally is updated to the terminal identifier assigned to the terminal by the second access network device.

[0315] S611, AMF sends the first message to SMF.

[0316] Among them, the first message is used to request the SMF to update the access network tunnel information of the terminal's session to the access network tunnel information allocated by the second access network device to the terminal.

[0317] Correspondingly, the SMF receives the first message and updates the access network tunnel information of the terminal's session to the access network tunnel information allocated to the terminal by the second access network device.

[0318] In an embodiment of the present application, the first message in step S611 carries indication information for instructing the SMF to update the access network tunnel information of the terminal, but does not include indication information for instructing the SMF to request the UPF to allocate core network tunnel information for the terminal.

[0319] As an example, when SMF stores the above-mentioned third correspondence in step S607, the first message in S611 also carries the identifier of the terminal and the identifier of the second access network device. After receiving the first message, SMF determines the access network tunnel information corresponding to the identifier of the second access network device and the identifier of the terminal based on the third correspondence shown in Table 4 or Table 5 above, updates the access network tunnel information of all sessions of the terminal to the access network tunnel information, and executes step S612 based on the access network tunnel information.

[0320] As another example, when SMF stores the above-mentioned fourth correspondence in step S607, the first message in S611 also carries the identifier of one or more sessions. After receiving the first message, SMF updates the access network tunnel information of the one or more sessions to the access network tunnel information allocated by the second access network device to the terminal based on the fourth correspondence, and executes step S612 based on the access network tunnel information.

[0321] In some possible implementations, the first message sent by the AMF to the SMF may also carry capability information of the second access network device. Exemplarily, the second switching time information corresponding to the above Table 1 may also include capability information of the access network device corresponding to the identifier of the access network device. The AMF determines to switch the terminal to the second access network device based on the second switching time information, and determines the |

[0322] The identifier of the second access network device, the capability information of the second access network device, and the identifier of the terminal. Among them, the capability information of the access network device includes one or more of the tracking area list (supported TA list) supported by the access network device, the supported data network name / single network slice selection support information (supported DNN / S-NSSAI), and the supported QoS flows. For example, the SMF can set the access network tunnel information of all sessions of the terminal based on the capability information of the second access network device and the access network tunnel information allocated by the second access network device to the terminal, and release the QoS flows not supported by the second access network device.

[0323] In an embodiment of the present application, in order to avoid the situation where the AMF receives the path switching message in step S606 and actively triggers the execution of step S610 based on the second switching time information, which leads to an unknown program error, as an example, after determining to switch the terminal to the second access network device, the AMF can determine not to execute step S611 based on the fact that the terminal identifier assigned to the terminal by the second access network device is not stored in the first corresponding relationship, but to execute the above steps S606-S608 based on the path switching message sent by the second access network device. Or, as another example, the AMF records the indication information of whether the second access network device has assigned the terminal identifier and the access network tunnel to the terminal. When the AMF determines that the second access network device has assigned the terminal identifier and the access network tunnel information to the terminal based on the indication information, the AMF executes the above steps S610 and S611 based on the second switching time information.

[0324] S612, SMF sends a second message to UPF.

[0325] In the embodiment of the present application, the second message in step S612 carries the access network tunnel information of the terminal, and does not carry the indication information requesting the UPF to allocate the core network tunnel information of the terminal. The description of the second message can refer to the relevant description in step S406, which will not be described in detail here.

[0326] S613, the second access network device communicates with the UPF based on the core network tunnel information and access network tunnel information of the terminal.

[0327] In an embodiment of the present application, after step S608 or step S612, the second access network device can communicate based on the core network tunnel information and access network tunnel information of the terminal to serve the session of the terminal.

[0328] In an embodiment of the present application, when the terminal accesses the second access network device for the first time, referring to steps S606-S608, the second access network device requests UPF to allocate core network tunnel information to the terminal through a path switching message, and sends the terminal identifier allocated to the terminal by the second access network device to AMF through a path switching request message; after the second access network device receives the core network tunnel information of the terminal, it allocates access network tunnel information to the terminal and sends the access network tunnel information to AMF, AMF stores the above-mentioned first correspondence based on the path switching message, and sends the access network tunnel information to SMF, and SMF stores the above-mentioned third correspondence based on the update request message.

[0329] When the terminal accesses the second access network device again, referring to steps S609 to S612, based on the fact that the second access network device has stored the core network tunnel information of the terminal, the second access network device no longer sends a path switching message to the AMF, thereby reducing the request and waiting time for the core network tunnel information, improving the signaling storm problem of the NG interface caused by the terminal frequently executing the switching process, and improving the switching efficiency. In addition, based on the second switching time information and the first corresponding relationship, the AMF actively updates the second identifier of the terminal and sends the first message of the terminal to the SMF, and the SMF updates the N3 path information of the terminal based on the first message and the third corresponding relationship, ensuring the integrity of the related air interface switching, N2 information update, and N3 interface switching when the terminal switches from the first access network device to the second access network device, thereby ensuring the normal Internet access function of the terminal after the switching process is executed.

[0330] Among them, air interface switching refers to switching the terminal from communicating with the core network through the air interface corresponding to the first access network device to communicating with the core network through the air interface corresponding to the second access network device based on the switching request message; N2 information update refers to switching the AMF from serving the terminal through the NG interface corresponding to the first access network device to serving the terminal through the NG interface corresponding to the second access network device based on the path switching message, and the N2 information update includes the update of the second identifier; N3 interface switching refers to switching the UPF from serving the terminal through the N4 interface corresponding to the first access network device to serving the terminal through the N4 interface corresponding to the second access network device based on the second message.

[0331] The following combination Figure 7The interaction diagram shown in the figure introduces an application of the communication method provided in the embodiment of the present application by taking the combination of the above-mentioned method 2 and method 4 as an example, in which the terminal identifier and access network tunnel information allocated by the second access network device to the terminal are sent in advance to the AMF, and the type of the tunnel information (access network tunnel information and core network tunnel information) is the tunnel information of session granularity. It should be noted that if the second access network device and the AMF can directly identify the terminal based on the UE ID without the RAN UE NGAP ID identifier, then Figure 7 The communication method shown may not include a solution for terminal identification. It should be noted that other access network devices in the specification may be replaced with the second access network device without limitation.

[0332] like Figure 7 As shown, the method comprises the following steps:

[0333] S701: A terminal sends a session establishment request for a first session to a first access network device.

[0334] Correspondingly, the first access network device receives the session establishment request.

[0335] In the embodiment of the present application, the access network device currently accessed by the terminal is the first access network device, and the first session may be any session established by the terminal through the first access network device.

[0336] In the embodiment of the present application, the session establishment request is used as a request trigger condition for the first access network device to request other access network devices to allocate access network tunnel information and terminal identification to the terminal. That is, whenever the terminal establishes a new session through the first access network device, after the first access network device receives the session establishment request, the first access network device triggers the execution of step S702.

[0337] S702: The first access network device requests other access network devices to allocate access network tunnel information and a terminal identifier to the terminal.

[0338] The other access network device includes a second access network device, and the second access network device is an access network device adjacent to the first access network device in the positive direction of the satellite running direction. The description of the other access network device can also refer to the relevant description in the above step S403, which will not be described in detail here.

[0339] S703, other access network devices respectively send access network tunnel information and terminal identifier allocated to the terminal to the first access network device.

[0340] Correspondingly, the first access network device receives the access network tunnel information and the terminal identifier allocated to the terminal by other access network devices.

[0341] In an embodiment of the present application, the first access network device may simultaneously request other access network devices to allocate access network tunnel information and terminal identification to the terminal through the same request message. Alternatively, the first access network device requesting other access network devices to allocate terminal identification to the terminal and requesting other access network devices to allocate access network tunnel information to the terminal may also be included in different request messages, which is not limited in this document.

[0342] As an example, a first access network device sends a first request and a second request to other access network devices respectively, the first request being used to request that the other access network devices allocate access network tunnel information for one or more sessions currently newly created by the terminal, and the second request being used to request that the other access network devices allocate a terminal identifier for the terminal. Based on the first request, the other access network devices allocate access network tunnel information for the one or more sessions of the terminal, and based on the second request, the other access network devices allocate a terminal identifier for the terminal. The first access network device receives a first response sent by the other access network devices respectively, the first response corresponding to the first request, the first response carrying the access network tunnel information allocated by the corresponding access network device to the terminal, and the first access network device receives a second response sent by the other access network devices respectively, the second response corresponding to the second request, and the second response carrying the terminal identifier allocated by the corresponding access network device to the terminal.

[0343] As another example, the first access network device sends a third request to other access network devices respectively (the third request includes the request content of the first request and the second request mentioned above), and the third request is used to request other access network devices to allocate a terminal identifier for the terminal and to allocate access network tunnel information for one or more newly created sessions of the terminal. For example, the third request carries the identifiers of one or more newly created sessions of the terminal and the first identifier of the terminal. Based on the third request, the other access network device allocates access network tunnel information for each session of the terminal and allocates a terminal identifier for the terminal; the first access network device receives a third response sent by the other access network device respectively, and the third response carries the first identifier of the terminal, the terminal identifier allocated to the terminal by the access network device corresponding to the first response, and the access network tunnel information allocated to each session of the terminal by the access network device corresponding to the first response.

[0344] In an embodiment of the present application, when the first access network device requests other access network devices to allocate access network tunnel information and terminal identifiers to the terminal through the above-mentioned third request, the session establishment request in the above-mentioned step S701 can be used as a request trigger condition for triggering the first access network device to send a third request to other access network devices. Among them, each time any one of the other access network devices responds to the third request of the same terminal, the terminal identifier allocated to the terminal is the same. Alternatively, any one of the other access network devices responds to the third request of the same terminal, and if it is determined that the terminal identifier has been allocated to the terminal, the terminal identifier is no longer allocated to the terminal, and the third response sent by the access network device to the AMF carries the access network tunnel information allocated by the access network device to the terminal, but does not carry the terminal identifier allocated by the access network device to the terminal.

[0345] It should be noted that the embodiment of the present application uses the above-mentioned session establishment request as a request trigger condition for triggering the first access network device to request other access network devices to allocate access network tunnel information and terminal identification to the terminal through a third request. It is only an example. The request trigger condition corresponding to the third request may also be other conditions. For example, the request trigger condition may also be that the first access network device receives a session establishment acceptance message sent by AMF.

[0346] In an embodiment of the present application, when the first access network device requests other access network devices to allocate access network tunnel information and terminal identification to the terminal through the above-mentioned first request and second request, the request trigger condition corresponding to the first request and the second request may be the session establishment request in the above-mentioned step S701, but is not limited to this. For example, the request trigger condition of the first request and the second request may also be that the first access network device receives a session establishment acceptance message sent by the AMF. For another example, the request trigger condition of the second request may also be: the first access network device is a preset access network device. For the introduction of the preset access network device, please refer to the relevant description above.

[0347] It is understandable that the first access network device requests other access network devices to allocate access network tunnel information and terminal identification to the terminal through the third request, and two tasks can be processed in the same message, achieving twice the result with half the effort, and reducing the signaling interaction of the Xn interface between the first access network device and the second access network device to a certain extent, thereby reducing performance loss. The first access network device requests other access network devices to allocate access network tunnel information and terminal identification to the terminal through the first request and the second request respectively, decoupling the two different tasks, making the program design simpler, and reducing the program response time to a certain extent.

[0348] S704, the first access network device sends the first information to AMF.

[0349] The first information may include access network tunnel information and a terminal identifier allocated by other access network devices to the terminal.

[0350] Accordingly, the AMF receives the first information.

[0351] Exemplarily, the first information includes a terminal identifier assigned by the second access network device to the terminal, an identifier of the access network device, an identifier of each session of the terminal, access network tunnel information corresponding to the identifier of each session of the terminal assigned by the second access network device to the terminal, and a terminal identifier assigned by the first access network device to the terminal, wherein the first information carries the terminal identifier assigned by the first access network device to the terminal to indicate to the AMF the terminal to which the first information corresponds.

[0352] In an embodiment of the present application, after receiving the first information, the AMF may store a fifth correspondence, which is used to record the terminal identifier assigned by the access network device to the terminal and the access network tunnel information assigned to each session of the terminal. Exemplarily, the fifth correspondence includes the identifier of the terminal, the identifier of the second access network device, the terminal identifier assigned by the second access network device to the terminal, the identifier of each session of the terminal, and the correspondence between the access network tunnel information corresponding to the identifier of each session of the terminal. For example, the data corresponding to the same terminal contained in the fifth correspondence is shown in Table 7 below. The fifth correspondence may include data corresponding to one terminal, or may include data corresponding to multiple terminals, which is not limited in this article.

[0353] Table 7

[0354]

[0355] In some possible implementations, the first information also includes the access network tunnel information allocated by the first access network device for the first session (the first session is the current newly created session). When establishing the first session, the first access network device does not send a path switching message carrying the access network tunnel information allocated by the first access network device for the first session to the AMF. After receiving the first information, the AMF actively sends a first message about the first session to the SMF based on the access network tunnel information allocated by the access network device (that is, the first access network device) currently accessed by the terminal for the session of the terminal. The first message carries the identifier of the first session and the access network tunnel information allocated by the first access network device for the first session. As a result, the access network tunnel information allocated by the first access network device for the newly established first session is included in the first information and sent to the AMF instead of being sent to the AMF through a path switching message, which further improves the signaling storm problem of the NG interface and improves the switching efficiency.

[0356] S705, AMF requests UPF to allocate core network tunnel information to the terminal.

[0357] As an example, the indication information for instructing AMF to request UPF to allocate core network tunnel information for the terminal through SMF can be sent to AMF in the same message as the first information in step S704. As another example, the indication information and the first information may not be included in the same message, that is, the first access network device sends the indication information to AMF through another message.

[0358] Specifically, the AMF may instruct the SMF to request the UPF to allocate core network tunnel information for the terminal through an update request message, and the update request message carries indication information for instructing the SMF to request the UPF to allocate core network tunnel information for the terminal. In response to the update request message, the SMF requests the UPF to allocate core network tunnel information for the terminal through an N4 session modification request, and the N4 session modification request includes indication information for instructing the UPF to allocate core network tunnel information for the terminal.

[0359] In an embodiment of the present application, the AMF may request the UPF to allocate core network tunnel information for each session of the terminal. For example, the terminal establishes session 1 and session 2 through the first access network device, and the AMF sends update request message 1 and update request message 2 to the UPF through the SMF, wherein the update request message 1 is used to request the UPF to allocate core network tunnel information for the session 1, and the update request message 2 is used to request the UPF to allocate core network tunnel information for the session 2.

[0360] Alternatively, AMF may also request UPF to allocate core network tunnel information for all sessions of the terminal at one time. For example, the terminal establishes session 1 and session 2 through the first access network device, and AMF sends update request message 3 to UPF through SMF, and the update request message 3 is used to request UPF to allocate core network tunnel information for session 1 and session 2.

[0361] In one example, after receiving the above request, UPF allocates core network tunnel information to the terminal, wherein the core network tunnel information corresponds to other access network devices; further, UPF sends the allocated core network tunnel information to the first access network device, for example, by sending the allocated core network tunnel information to the first access network device through AMF or SMF.

[0362] Among them, the request can carry information of other access network devices (for example, identification, or address, etc.), and then UPF allocates different core network tunnel information to the terminal for different access network devices. For example, the information of other access network devices includes the second access network device and the third access network device. For the second access network device, UPF allocates the second core network tunnel information to the terminal, and for the third access network device, UPF allocates the third core network tunnel information to the terminal.

[0363] The second core network tunnel information is used to establish a tunnel between the UPF and the second access network device for the terminal when the terminal accesses the second access network device, and the tunnel is used to carry the data of the terminal. The third core network tunnel information is used to establish a tunnel between the UPF and the third access network device for the terminal when the terminal accesses the third access network device, and the tunnel is used to carry the data of the terminal.

[0364] It can be seen that the core network tunnel information corresponds to other access network devices. It can be understood that the second core network tunnel information corresponds to the second access network device, and the third core network tunnel information corresponds to the third access network device.

[0365] S706, UPF sends the core network tunnel information allocated to the terminal to the corresponding access network device.

[0366] Correspondingly, the access network device receives the core network tunnel information allocated by the UPF to the terminal.

[0367] In one example, UPF can send the core network tunnel information allocated to the terminal to the first access network device through AMF and SMF, and the first access network device then sends the core network tunnel information to other access network devices (including the second access network device and the third access network device) accordingly. For example, the second core network tunnel information and the third core network tunnel information are sent to SMF, SMF sends the second core network tunnel information and the third core network tunnel information to AMF, AMF then sends the second core network tunnel information and the third core network tunnel information to the first access network device, the first access network device then sends the second core network tunnel information to the second access network device, and sends the third core network tunnel information to the third access network device.

[0368] In another example, UPF can directly send the core network tunnel information to the corresponding access network device through AMF and SMF, for example, send the second core network tunnel information to SMF, which is then forwarded by SMF to AMF, and then forwarded by AMF to the second access network device.

[0369] Exemplarily, in the process of the terminal accessing the first access network device and establishing a first session based on the first access network device (or it can also be understood as each time the terminal establishes a session), the UPF allocates corresponding core network tunnel information to the second access network device to serve the newly established session and sends it to the second access network device. The second access network device receives and stores the core network tunnel information, so that in step S709, the second access network device can not send a path switching message to the AMF based on the stored core network tunnel information of the terminal.

[0370] It should be noted that the above-mentioned other access network devices may include only one access network device, for example, the second access network device; in addition, the above-mentioned core network tunnel information allocated to the terminal can be replaced by the core network tunnel information allocated to the first session in step S701, without limitation.

[0371] S707, AMF obtains the second switching time information corresponding to the terminal.

[0372] S708: The first access network device sends a switching request message corresponding to the terminal to the second access network device based on the first switching time information corresponding to the terminal.

[0373] Correspondingly, the second access network device receives the switching request message.

[0374] For detailed description of the second switching time information, the first switching time information, and the switching request message, please refer to Figure 6 Steps S601-S604, or Figure 4 The relevant descriptions in steps S401 and S404 are not described in detail here.

[0375] S709, the second access network device determines not to send a path switching message to the AMF based on the stored core network tunnel information of the terminal.

[0376] Exemplarily, after receiving the switching request message from the terminal, the second access network device may not determine whether the second access network device stores the core network tunnel information of the terminal, but directly does not send the corresponding path switching message to the AMF in response to the switching request message.

[0377] S710, AMF determines to switch the terminal to the second access network device based on the second switching time information.

[0378] Exemplarily, the AMF determines, based on the second switching time information, that the identifier of the target access network device of the terminal corresponding to the current time is the identifier of the second access network device; then, based on the identifier of the second access network device and the fifth corresponding relationship stored locally, determines the terminal identifier assigned to the terminal by the second access network device, and updates the second identifier of the terminal recorded locally to the terminal identifier assigned to the terminal by the second access network device (which can also be understood as updating the N2 information).

[0379] S711, AMF sends the first message to SMF.

[0380] The first message may carry access network tunnel information allocated by the second access network device to the terminal.

[0381] Accordingly, the SMF receives the first message.

[0382] In an embodiment of the present application, the first message may also be an update request message. The first message does not include indication information for indicating that the SMF requests the UPF to allocate core network tunnel information to the terminal. Also, the first message may carry indication information for indicating that the SMF updates the access network tunnel information of the terminal, or the first message may not carry the indication information, and the first message may carry the access network tunnel information allocated by the second access network device to the terminal, which may be used to instruct the SMF to update the access network tunnel information of the terminal.

[0383] Exemplarily, AMF determines the access network tunnel information allocated by the second access network device to each session of the terminal based on the fifth corresponding relationship, and sends the first message of the terminal based on the access network tunnel information SMF.

[0384] As an example, when the number of sessions of the terminal is greater than or equal to 2, the first message may correspond to at least two sessions of the terminal (for example, all sessions), and the first message carries the identifiers of at least two sessions of the terminal and the access network tunnel information corresponding to the identifier of each session.

[0385] As another example, the first message may also correspond to a session of the terminal. Specifically, the first message carries the identifier of the first session of the terminal and the access network tunnel information corresponding to the first session. The first session is any session of the terminal. If the number of sessions of the terminal is greater than or equal to 2, the AMF may send the first message corresponding to each session of the terminal to the SMF one by one.

[0386] S712, SMF sends the second message of the terminal to UPF.

[0387] Accordingly, the UPF receives the second message.

[0388] In the embodiment of the present application, the second message in step S712 carries the access network tunnel information of the terminal, and does not carry the indication information requesting the UPF to allocate the core network tunnel information of the terminal. The description of the second message can refer to the relevant description in step S406, which will not be described in detail here.

[0389] S713, the second access network device communicates with the UPF based on the core network tunnel information and access network tunnel information of the terminal.

[0390] In an embodiment of the present application, after step S608 or step S613, the second access network device can communicate based on the core network tunnel information and access network tunnel information of the terminal to serve the session of the terminal.

[0391] In an embodiment of the present application, before the terminal switches to the second access network device, the terminal identifier assigned by the second access network device to the terminal and the access network tunnel information respectively assigned to the terminal session will be sent to AMF, and the core network tunnel information assigned by UPF to the second access network device serving the terminal will also be sent to the second access network device. Based on this, when the terminal switches to the second access network device (that is, the second access network device receives a switching request message about the terminal), the second access network device does not send a path switching message to AMF, and does not need to request and wait for UPF to allocate core network tunnel information to the terminal, thereby improving the signaling storm problem of the NG interface caused by the terminal frequently executing the switching process and improving the switching efficiency. And based on the second switching time information and the fifth corresponding relationship shown in Table 7, AMF actively updates the N2 information of the terminal and actively sends the first message of the terminal to SMF to ensure the integrity of the terminal switching process.

[0392] The following combination Figure 8 The interaction diagram shown in the figure introduces an application of the communication method provided in the embodiment of the present application by taking the above-mentioned method 2 that the second access network device allocates a terminal identifier to the terminal and sends it to the AMF in advance, and the access network tunnel information of the second access network device serving the terminal is allocated by the SMF as an example. Figure 8 As shown, the method comprises the following steps:

[0393] S801: A terminal sends a session establishment request for a first session to a first access network device.

[0394] Correspondingly, the first access network device receives the session establishment request.

[0395] For the description of the first session, please refer to the relevant description in step S701 above.

[0396] S802: The first access network device requests other access network devices to allocate a terminal identifier to the terminal.

[0397] Specifically, the first access network device sends a second request to the other access network devices respectively, and the second request is used to request the other access network devices to allocate a terminal identifier for the terminal. For example, the second request carries the first identifier of the terminal, and the first identifier can be the UE ID or C-RNTI of the terminal. Based on the second request, the other access network devices allocate a terminal identifier for the terminal respectively, and send a second response to the first access network device respectively, and the second response carries the terminal identifier allocated by the corresponding access network device to the terminal. For example, the second response can carry the first identifier of the terminal and the terminal identifier allocated by the corresponding access network device to the terminal.

[0398] In an embodiment of the present application, the above-mentioned session establishment request can serve as a request trigger condition for the first access network device to request other access network devices to assign a terminal identifier to the terminal, but the request trigger condition of the first request is not limited to this. For details, please refer to the relevant instructions on the request trigger condition of the first request in step S703 above, which will not be described in detail here.

[0399] For the description of other access network devices, please refer to the relevant description in step S403 above, which will not be described in detail here.

[0400] S803: Other access network devices respectively send the terminal identifier allocated to the terminal to the first access network device.

[0401] Correspondingly, the first access network device receives the terminal identifier allocated to the terminal by other access network devices.

[0402] S804, the first access network device sends the terminal identifier allocated to the terminal by other access network devices to the AMF.

[0403] Correspondingly, AMF receives the terminal identifier allocated to the terminal by the other access network device.

[0404] Exemplarily, based on the second response, AMF stores the terminal identifier allocated to the terminal by other access network devices, for example, storing the sixth correspondence shown in Table 8 below.

[0405] Table 8

[0406]

[0407] S805, request UPF to allocate corresponding core network tunnel information to the terminal.

[0408] As an example, in the above S804, the first access network device may also include indication information in the message of the terminal identifier assigned to the terminal by other access network devices to AMF, and the indication information is used to instruct AMF to request UPF to allocate corresponding core network tunnel information to the terminals served by other access network devices through SMF. As another example, the indication information and the terminal identifier assigned to the terminal by other access network devices may not be in the same message, and the first access network device may send the indication information to AMF through another message.

[0409] As another example, the first access network device sends the terminal identifier allocated to the terminal by other access network devices to AMF, triggering AMF to request UPF through SMF to allocate corresponding core network tunnel information to the service terminals of other access network devices respectively.

[0410] Alternatively, in another possible implementation, triggering AMF to request UPF to allocate core network tunnel information through SMF may not depend on whether AMF receives the terminal identifier allocated to the terminal by other access network devices, but may be other triggering conditions, which is not limited in this document.

[0411] For detailed instructions on how AMF requests UPF through SMF to allocate corresponding core network tunnel information to other access network device service terminals, please refer to step S705 above.

[0412] S806, UPF sends the core network tunnel information allocated to the terminal to the corresponding access network device.

[0413] Correspondingly, the access network device receives the core network tunnel information allocated by the UPF to the terminal.

[0414] Specifically, UPF can send the core network tunnel information corresponding to the service terminals of other access network devices to the first access network device through AMF and SMF, and the first access network device then sends the core network tunnel information to other access network devices (including the second access network device) accordingly, for example, sending the core network tunnel information corresponding to the service terminal of the second access network device to SMF, SMF forwards it to AMF, AMF forwards it to the first access network device, and the first access network device forwards it to the second access network device. Alternatively, UPF can also directly send the core network tunnel information to the corresponding access network device through AMF and SMF, for example, sending the core network tunnel information of the service terminal of the second access network device to SMF, SMF forwards it to AMF, and AMF forwards it to the second access network device. For detailed instructions on how UPF sends the core network tunnel information allocated to the service terminals of other access network devices to the corresponding access network devices, please refer to step S706 above.

[0415] Exemplarily, during the process of the terminal accessing the first access network device and establishing a first session based on the first access network device (or it can also be understood as each time the terminal establishes a session), the UPF allocates the corresponding core network tunnel information for the newly established session of the terminal served by the second access network device and sends it to the second access network device. The second access network device stores the core network tunnel information, so that in step S808, the second access network device can not send a path switching message to the AMF based on the stored core network tunnel information of the terminal.

[0416] Among them, the service granularity of the core network tunnel information can be session granularity, slice granularity, UE-RAN granularity, or RAN granularity, which is not limited in this article.

[0417] S807: The first access network device sends a switching request message corresponding to the terminal to the second access network device based on the first switching time information corresponding to the terminal.

[0418] Correspondingly, the second access network device receives the switching request message.

[0419] For the first switching time information, please refer to the relevant description in step S401 above, which will not be described in detail here.

[0420] S808, the second access network device determines not to send a path switching message to the AMF based on the stored core network tunnel information of the terminal.

[0421] As an example, the second access network device may not need to determine whether the second access network device has stored the core network tunnel information of the terminal, but may directly send a corresponding path switching message to the AMF in response to the switching request message.

[0422] S809: AMF determines to switch the terminal to the second access network device based on the second switching time information.

[0423] Exemplarily, the AMF determines, based on the second switching time information, that the identifier of the target access network device of the terminal corresponding to the current time is the identifier of the second access network device; then, based on the identifier of the second access network device and the above-mentioned sixth correspondence stored locally by the AMF, determines the terminal identifier assigned to the terminal by the second access network device, and updates the second identifier of the terminal recorded locally to the terminal identifier assigned to the terminal by the second access network device.

[0424] S810, AMF sends the first message of the terminal to SMF, and the first message carries the identifier of the second access network device.

[0425] Accordingly, the SMF receives the first message.

[0426] In an embodiment of the present application, the first message is used to request the SMF to allocate the first access network tunnel information to the terminal based on the identifier of the second access network device, and update the access network tunnel information of the terminal session to the first access network tunnel information. The first access network tunnel information can be access network tunnel information of session granularity, slice granularity, UE-RAN granularity, or RAN granularity.

[0427] S811, SMF allocates first access network tunnel information to the terminal in response to the first message.

[0428] Exemplarily, the SMF stores one or more allocatable access network tunnel information corresponding to the identifier of the access network device, so that the SMF can allocate the corresponding first access network tunnel information to the terminal based on the identifier of the second access network device carried in the first message.

[0429] As an example, when the access network tunnel information of the terminal is at a session granularity or a slice granularity, the above-mentioned first message may carry the identifier of one or more sessions of the terminal and the identifier of the second access network device, and the first message is used to request the SMF to allocate access network tunnel information to the one or more sessions of the terminal based on the identifier of the second access network device, and update the access network tunnel information of the one or more sessions based on the allocated access network tunnel information. Alternatively, when the access network tunnel information of the terminal is at a session granularity, the first message may also carry the identifier of the terminal, and the SMF determines the identifier of one or more sessions corresponding to the terminal based on the identifier of the terminal, and allocates access network tunnel information to the one or more sessions. In this case, the first access network tunnel information in step S811 includes access network tunnel information corresponding to the identifiers of the one or more sessions.

[0430] As another example, when the access network tunnel information of the terminal is aggregated access network tunnel information of UE-RAN granularity or RAN granularity, the above-mentioned first message may carry the identifier of the terminal and the identifier of the second access network device, and the first message is used to request the SMF to allocate aggregated access network tunnel information to the terminal based on the identifier of the second access network device, and update the access network tunnel information of all sessions corresponding to the identifier of the terminal to the aggregated access network tunnel information. Alternatively, the first message may also carry the identifier of one or more sessions of the terminal and the identifier of the second access network device, and the update request is used to request the SMF to allocate corresponding aggregated access network tunnel information to the session of the terminal based on the identifier of the second access network device and the identifier of the session. In this case, the first access network tunnel information in step S811 is the aggregated access network tunnel information corresponding to the terminal and the second access network device.

[0431] In some possible implementations, after the SMF allocates access network tunnel information A to the first session of the terminal, the SMF may also store the correspondence between the identifier of the first session, the access network tunnel information A, and the second access network device. When the SMF receives the first message containing the identifier of the session A and the identifier of the second access network device next time, the access network tunnel information of the first session may be directly used with the access network tunnel information A previously allocated to the second access network device to serve the first session.

[0432] S812, SMF sends a second message to UPF.

[0433] For the description of the second message, please refer to the relevant description in S406 above, which will not be described in detail here.

[0434] In some possible implementations, after step S811, the SMF further executes step S813.

[0435] S813, SMF sends the above-mentioned first access network tunnel information to the second access network device.

[0436] In the embodiment of the present application, after SMF allocates the first access network tunnel information to the second access network device service terminal, the first access network tunnel information can be sent to the second access network device through AMF. Alternatively, the first access network tunnel information can be sent to the first access network device through AMF, and the first access network device sends the first access network tunnel information to the second access network device through the inter-satellite link.

[0437] As an example, the first access network tunnel information belongs to the access network tunnel information at the session granularity, and SMF sends the first access network tunnel information to the second access network device through AMF, including: SMF sends one or more session identifiers and the access network tunnel information corresponding to the one or more sessions to AMF, and AMF forwards the one or more session identifiers and the access network tunnel information corresponding to the one or more sessions to the second access network device.

[0438] It can be understood that SMF sends the identifiers of one or more sessions and the access network tunnel information corresponding to the one or more sessions to the second access network device through AMF, so that when the second access network device subsequently receives a message sent by UPF through access network tunnel information A, it can determine the session corresponding to the message, and the access network tunnel information A corresponds to one of the one or more sessions.

[0439] As another example, the first access network tunnel information belongs to aggregated access network tunnel information, and SMF sends the first access network tunnel information to the second access network device through AMF, including: SMF sends the first access network tunnel information and the identifier of the second access network device to AMF, and AMF forwards the first access network tunnel information to the second access network device.

[0440] Alternatively, in some possible implementations, the communication method provided in the present application includes the above steps S801-S812, and S814, wherein S814 is performed after step S812.

[0441] S814, UPF sends the above-mentioned first access network tunnel information to the second access network device.

[0442] Exemplarily, the UPF sending the above-mentioned first access network tunnel information to the second access network device includes: the UPF sending one or more session identifiers and the access network tunnel information corresponding to each session to the second access network device.

[0443] S815, the second access network device communicates with the UPF based on the core network tunnel information of the terminal and the first access network tunnel information.

[0444] For example, a GTP-U tunnel is established between the second access network device and the UPF for communication based on the core network tunnel information of the terminal and the above-mentioned first access network tunnel information.

[0445] In an embodiment of the present application, before the terminal switches to the second access network device, the terminal identifier assigned by the second access network device to the terminal will be sent to the AMF, and the core network tunnel information assigned by the UPF to the second access network device serving the terminal will also be sent to the second access network device. Based on this, when the terminal switches to the second access network device (that is, the second access network device receives a switching request message about the terminal), the second access network device does not send a path switching message to the AMF, that is, the second access network device does not need to request and wait for the UPF to allocate core network tunnel information to the terminal, thereby improving the switching efficiency. In addition, the SMF allocates access network tunnel information to the second access network device serving the terminal, and the second access network device does not need to send the access network tunnel information to the AMF, thereby reducing signaling interaction and further improving the switching efficiency. In addition, there is no need to request other access network devices (including the second access network device) through the first access network device to obtain the access network tunnel information allocated to the terminal, thereby reducing the signaling interaction of the Xn interface between the first access network device and the second access network device, thereby further reducing performance loss and improving switching efficiency.

[0446] The following combination Fig. 9, taking the second access network device allocating access network tunnel information to the terminal, the type of tunnel information (access network tunnel information and core network tunnel information) is UE-RAN granularity or RAN granularity tunnel information, the second access network device allocating access network tunnel information to the terminal is sent to AMF through the above method 1, and AMF sends the second service time information to SMF, so that SMF can actively trigger the execution of the process related to the terminal switching to the second access network device, and further omit the switching request message sent by AMF to SMF through the N11 interface in the switching process as an example, an application of the communication method provided in the embodiment of the present application is introduced. Fig. 9 As shown, the method comprises the following steps:

[0447] S901, AMF obtains the second switching time information corresponding to the terminal.

[0448] S902, AMF sends second switching time information to the first access network device.

[0449] Correspondingly, the first access network device receives the second switching time information sent by the AMF.

[0450] S903: The first access network device determines first switching time information based on the second switching time information.

[0451] For the description of S901-S903, please refer to the relevant description of S601-S603 above, which will not be described in detail here.

[0452] S904, AMF sends the second switching time information to SMF.

[0453] Correspondingly, the SMF receives the second switching time information.

[0454] In the embodiment of the present application, S902 and S904 may be executed simultaneously or sequentially, and the order is not limited.

[0455] S905: The first access network device sends a switching request message corresponding to the terminal to the second access network device based on the first switching time information corresponding to the terminal.

[0456] Correspondingly, the second access network device receives the switching request message.

[0457] S906: The second access network device determines whether the core network tunnel information of the terminal has been stored.

[0458] The core network tunnel information may be at a UE-RAN granularity or a RAN granularity.

[0459] In the embodiment of the present application, when the second access network device determines that the core network tunnel information of the terminal is not stored, the second access network device executes step S907; when the second access network device determines that the core network tunnel information of the terminal is stored, the second access network device executes step S910.

[0460] S907, the second access network device sends a path switching message to AMF.

[0461] Correspondingly, AMF requests UPF to allocate the core network tunnel information of the terminal based on the path switching message.

[0462] For details, please refer to the relevant instructions in step S606 above, which will not be described in detail here.

[0463] S908, sending the core network tunnel information of the terminal allocated by the UPF to the second access network device.

[0464] For details, please refer to the relevant instructions in step S607 above, which will not be described in detail here.

[0465] S909, send the access network tunnel information of the terminal allocated by the second access network device to SMF and UPF through AMF.

[0466] For details, please refer to the relevant instructions in step S608 above, which will not be described in detail here.

[0467] S910, the second access network device determines not to send a path switching message to the AMF based on the core network tunnel information of the terminal stored therein.

[0468] In an embodiment of the present application, when the second access network device determines that a terminal identifier and an aggregated access network tunnel have been assigned to the terminal, it does not send a path switching message to the AMF, thereby improving the signaling storm problem of the NG interface caused by the terminal frequently executing the switching process and improving the switching efficiency.

[0469] S911, AMF determines to switch the terminal to the second access network device based on the second switching time information, and determines not to send the first message to SMF.

[0470] In the embodiment of the present application, after determining to switch the terminal to the second access network device, the AMF determines not to send the first message to the SMF based on the second service time information of the terminal sent to the SMF in step S904. Thus, the signaling storm problem of the N11 interface in the terminal switching process is improved, the performance loss is further reduced, and the switching efficiency is improved.

[0471] Regarding how to avoid the AMF executing both step S911 and the above steps S907-S909 based on the path switching message sent by the second access network device, resulting in an unknown program error, please refer to the relevant description in step S611 above.

[0472] S912: SMF determines to switch the terminal to the second access network device based on the second switching time information.

[0473] As an example, if the SMF stores the third correspondence shown in Table 4 or Table 5 above, then 'SMF determines to switch the terminal to the second access network device based on the second switching time information', which may specifically include: SMF determines that the identifier of the current target access network device of the terminal is the identifier of the second access network device based on the second switching time information (refer to Table 1), and determines the aggregated access network tunnel information corresponding to the identifier of the terminal and the identifier of the second access network device based on the locally stored third correspondence; based on the aggregated access network tunnel information, SMF updates the access network tunnel information corresponding to each session of the terminal in the local configuration to the aggregated access network tunnel information allocated to the terminal by the second access network device.

[0474] As another example, if the fourth correspondence shown in Table 6 above is stored in SMF, then 'SMF determines to switch the terminal to the second access network device based on the second switching time information' may specifically include: SMF determines that the identifier of the terminal's current target access network device is the identifier of the second access network device based on the second switching time information (refer to Table 1), and determines the aggregated access network tunnel information corresponding to the session of the terminal and the identifier of the second access network device based on the fourth correspondence stored locally, and updates the access network tunnel information of the terminal's session based on the aggregated access network tunnel information.

[0475] S913, SMF sends a second message to UPF.

[0476] In the embodiment of the present application, after the SMF determines to switch the terminal to the second access network device based on the second switching time information, it sends a second message to the UPF. The description of the second message can refer to the relevant description in step S406, which will not be described in detail here.

[0477] In an embodiment of the present application, AMF sends the second service time information to SMF, and SMF can actively trigger the execution of related processes related to the terminal switching to the second access network device, further omitting the switching request message sent by AMF to SMF through the N11 interface in the switching process, further alleviating the communication pressure of the N11 interface and improving the switching efficiency.

[0478] S914, the second access network device communicates with the UPF based on the core network tunnel information and access network tunnel information of the terminal.

[0479] The following combination Fig.10 The interactive diagram shown in the figure introduces an application of the communication method provided in the embodiment of the present application by taking the above-mentioned method 2 and the combination of method 2 as an example, the terminal identifier and access network tunnel information allocated by the second access network device to the terminal are sent to AMF in advance, and the type of the access network tunnel information is the access network tunnel information of session granularity, and AMF sends the service time of the second access network device serving the terminal and the access network tunnel information allocated by the second access network device to the terminal in advance to SMF, so that SMF can actively trigger the execution of the process related to the terminal switching to the second access network device. Fig.10 As shown, the communication method provided in the embodiment of the present application includes the following steps:

[0480] S1001: A terminal sends a session establishment request to a first access network device.

[0481] Correspondingly, the first access network device receives the session establishment request.

[0482] S1002: The first access network device requests other access network devices to allocate access network tunnel information and a terminal identifier to a terminal.

[0483] S1003: The first access network device receives access network tunnel information and a terminal identifier allocated to the terminal by other access network devices.

[0484] S1004, the first access network device sends the first information to the AMF, where the first information includes the access network tunnel information and terminal identifier allocated to the terminal by other access network devices.

[0485] Accordingly, the AMF receives the first information.

[0486] S1005, request UPF to allocate core network tunnel information to the terminal.

[0487] S1006, UPF sends the core network tunnel information allocated to the terminal to the corresponding access network device.

[0488] S1007, AMF obtains the second switching time information corresponding to the terminal.

[0489] For detailed description of steps S1001-S1007, please refer to the relevant description of steps S701-S707 above.

[0490] S1008, AMF sends the second information to SMF based on the second switching time information and the access network tunnel information and terminal identifier allocated to the terminal by other access network devices.

[0491] Correspondingly, the SMF receives the second information, which includes the service time of the second access network device serving the terminal and the access network tunnel information allocated by the second access network device to the terminal.

[0492] As an example, the second information includes the second switching time information corresponding to the terminal and the access network tunnel information allocated to the terminal by the other access network devices. For example, the second information includes other data in Table 1 and Table 7 except the terminal identifier. It should be noted that the identifier of the terminal session in the second information sent by AMF to SMF can be PDU session ID or SM context ID, wherein the PDU session ID can be understood as the public identifier of the session, and the SM context ID is a private identifier allocated by SMF to the session and used to identify the session between SMF and AMF.

[0493] For example, AMF can determine that the identifier of the target access network device of UE1 is RAN2 ID based on Table 1, and based on the PDU session ID1 of the session corresponding to UE1, the RAN2 ID, and the above Table 7, determine the access network tunnel information corresponding to the PDU session ID1 and the RAN2 ID as the access network tunnel information of the session.

[0494] As another example, the second information includes the identifier of each session of the terminal, the service time of the access network device serving the terminal, and the corresponding relationship between the access network tunnel information corresponding to the service time. Among them, the identifier of the session can be the PDU session ID of the session or the SM context ID of the session. The following takes the identifier of the session in the second information as the PDU session ID as an example, and introduces the data contained in the second information in combination with Table 9.

[0495] For example, as shown in Table 9 below, PDU session ID1 and PDU session ID2 correspond to two different sessions of the terminal respectively. The session corresponding to PDU sessionID1 is in the two time periods of 00:00-00:05 and 05:00-05:05 (for example, the terminal switches to the first access network device in these two time periods), and uses tunnel information AN tunnel info1 (for example, the access network tunnel information allocated by the first access network device to the PDU session ID1 of the terminal is AN tunnel info1); the session corresponding to PDU session ID2 is in the two time periods of 00:00-00:05 and 05:00-05:05 (for example, the terminal switches to the second access network device in these two time periods), and uses tunnel information AN tunnel info2 (for example, the access network tunnel information allocated by the first access network device to the PDU session ID2 of the terminal is AN tunnel info2).

[0496] Among them, Table 9 does not actually include the data content marked in brackets. The identifier of the access network device marked in brackets in the service time column of Table 9 is only for the convenience of indicating which access network device the terminal accesses to. For example, '00:00-00:05, 05:00-05:05 (RAN1)' means that the service time for the terminal to switch to RAN1 is 00:00-00:05, 05:00-05:05.

[0497] Table 9

[0498]

[0499] S1009: The first access network device sends a switching request message corresponding to the terminal to the second access network device based on the first switching time information corresponding to the terminal.

[0500] Correspondingly, the second access network device receives the switching request message.

[0501] S1010, the second access network device determines not to send a path switching message to the AMF based on the access network tunnel information and terminal identifier that have been allocated to the terminal.

[0502] S1011, AMF determines to switch the terminal to the second access network device based on the second switching time information.

[0503] For detailed description of steps S1009-S1011, please refer to the relevant description of steps S708-S710 above.

[0504] In an embodiment of the present application, after AMF determines to switch the terminal to the second access network device, it determines not to send the first message to SMF based on the fact that AMF has sent to SMF the access network tunnel information allocated to the terminal by other access network devices in step S1007, and the second service time information of the terminal has been sent to SMF in step S1010.

[0505] S1012, based on the second information, the SMF updates the access network tunnel information of the terminal's session to the access network tunnel information allocated by the second access network device to the session of the terminal.

[0506] As an example, the second information includes other data in the above Table 1 and Table 7 except the terminal identifier. Based on the second information, the SMF updates the access network tunnel information of the terminal's session to the access network tunnel information allocated by the second access network device to the session of the terminal, specifically including: based on Table 1, the SMF determines that the identifier of the target access network device of the terminal corresponding to the current time is the identifier of the second access network device, and based on the other data in Table 7 except the terminal identifier, determines the access network tunnel information A corresponding to the identifier of the second access network device and the first session of the terminal, and updates the access network tunnel information corresponding to the first session to the access network tunnel information A.

[0507] For example, the identifier of the target access network device corresponding to the current time in Table 1 is RAN2 ID (second access network device), the identifier of the first session of the terminal is PDU session ID1, and the access network tunnel information corresponding to the PDU session ID1 and the RAN2 ID is AN tunnelinfo3. Based on this, the access network tunnel information corresponding to one or more sessions of the terminal is updated to the access network tunnel information allocated by the second access network device to the corresponding session.

[0508] Or, as another example, the data included in the second information is as shown in Table 9 above, and the SMF updates the access network tunnel information of the session of the terminal to the access network tunnel information allocated by the second access network device to the session of the terminal based on the second information, specifically including: the SMF determines the service time corresponding to the current moment based on Table 9, and updates the access network tunnel information of the session (one or more) corresponding to the service time to the access network tunnel information corresponding to the session and corresponding to the service time. For example, the service time corresponding to the current moment is 00:00-00:05, and the session of the terminal includes PDUsession ID1 and PDU session ID2. The SMF updates the access network tunnel information of the session corresponding to the PDU session ID1 to AN tunnel info1 corresponding to the time of 00:00-00:05, and updates the access network tunnel information of the session corresponding to the PDU session ID2 to AN tunnel info2 corresponding to the time of 00:00-00:05.

[0509] S1013, SMF sends a second message to UPF, where the second message is used to request that the access network tunnel information corresponding to one or more sessions of the terminal be updated to the access network tunnel information allocated by the second access network device to the corresponding session.

[0510] In the embodiment of the present application, after the SMF determines to switch the terminal to the second access network device based on the second information, it sends a second message to the UPF. For the description of the second message, please refer to the relevant description in step S406, which will not be described in detail here.

[0511] S1014: The second access network device and the UPF communicate based on the core network tunnel information and access network tunnel information of the terminal. For example, the second access network device and the UPF establish a GTP-U tunnel for communication based on the core network tunnel information and access network tunnel information of the terminal.

[0512] In some other possible implementations, the method provided in the embodiment of the present application may also include steps S1001-S1012, S1015-S1016, and S1014.

[0513] S1015, SMF sends the above-mentioned second information to UPF.

[0514] Correspondingly, the UPF receives the second information, which includes the service time of the terminal accessing the second access network device and the access network tunnel information allocated by the second access network device to the terminal.

[0515] For the description of the second information, please refer to the relevant description in step S1012 above. It should be noted that in the second information sent by the SMF to the UPF, the session identifier can be the PDU session ID or N4 session ID of the session.

[0516] S1016, UPF updates the access network tunnel information of the terminal session based on the second information.

[0517] Specifically, the UPF updates the access network tunnel information of the session whose service time corresponds to the current time based on the second information, and performs step S1014 after step S1016. Regarding how the UPF determines the access network tunnel information corresponding to one or more sessions of the terminal corresponding to the current time based on the second information, reference may be made to the relevant description of the SMF determining the access network tunnel information corresponding to one or more sessions of the terminal corresponding to the current time based on the second information in step S1012 above.

[0518] Based on this, UPF actively triggers the execution of related processes for updating the access network tunnel information of the terminal session based on the service time through the second information. There is no need for SMF to send an N4 session update request to UPF, which further reduces the signaling interaction of the N4 interface in the terminal switching process, reduces performance loss, and improves switching efficiency.

[0519] The following combination Figure 8 The interactive diagram shown in the figure introduces an application of the communication method provided in the embodiment of the present application by taking the above-mentioned method 2 that the second access network device allocates a terminal identifier to the terminal and sends it to AMF in advance, the access network tunnel information of the second access network device serving the terminal is allocated by SMF, and AMF sends the second service time information to SMF, so that SMF can actively trigger the execution of the relevant process of switching the terminal to the second access network device and as an example. Fig.11 As shown, the communication method provided in the embodiment of the present application includes the following steps:

[0520] S1101: A terminal sends a session establishment request to a first access network device.

[0521] Correspondingly, the first access network device receives the session establishment request.

[0522] S1102: The first access network device requests other access network devices to allocate a terminal identifier to the terminal.

[0523] S1103: The first access network device receives a terminal identifier allocated to the terminal by other access network devices.

[0524] S1104, the first access network device sends the terminal identifier allocated to the terminal by other access network devices to the AMF.

[0525] S1105, request UPF to allocate core network tunnel information to the terminal.

[0526] S1106, UPF sends the core network tunnel information allocated to the terminal to the corresponding access network device.

[0527] For a detailed description of steps S1101 - S1104 , please refer to the above description of steps S801 - S806 .

[0528] S1107, AMF obtains the second switching time information corresponding to the terminal.

[0529] For detailed information on how to obtain the second switching time information, please refer to Figure 6 Steps S601-S604, or Figure 4 The relevant descriptions in steps S401 and S404 are not described in detail here.

[0530] S1108, AMF sends the second switching time information to SMF.

[0531] Correspondingly, the SMF receives the second switching time information sent by the AMF.

[0532] S1109, SMF allocates corresponding access network tunnel information to multiple access network device service terminals based on the second switching time information.

[0533] In an embodiment of the present application, the multiple access network devices include an access network device corresponding to the identifier of the access network device contained in the second switching time information. Optionally, the access network tunnel information allocated by the SMF to the terminal may be access network tunnel information of session granularity, UE-RAN granularity, or RAN granularity, which is not limited in this document.

[0534] Exemplarily, the access network tunnel information allocated by the SMF to the terminal belongs to the access network tunnel information of the session granularity. The SMF can allocate the access network tunnel information corresponding to the identifier of the access network device and the identifier of the session of the terminal based on the second switching time information shown in Table 1 above, and obtain and store the seventh correspondence between the data other than the terminal identifier in Table 7 above, or obtain and store the second information shown in Table 9 above. It should be noted that the identifier of the session in the seventh correspondence and the second information stored in the SMF can be either the PDUsession ID or the SMcontext ID.

[0535] In a possible implementation, after SMF allocates corresponding access network tunnel information to multiple access network device service terminals, SMF can send the access network tunnel information allocated by SMF to the access network device service terminal to the corresponding access network devices through AMF. Alternatively, SMF can also first send the corresponding access network tunnel information allocated to multiple access network device service terminals to the first access network device, and then the first access network device sends the access network tunnel information allocated by SMF to the access network device service terminal to the corresponding access network device through the inter-satellite link.

[0536] S1110: The first access network device determines to switch the terminal to the second access network device based on the first switching time information corresponding to the terminal, and sends a switching request message corresponding to the terminal to the second access network device.

[0537] Correspondingly, the second access network device receives the switching request message.

[0538] S1111, the second access network device determines not to send a path switching message to the AMF based on the terminal identifier having been allocated to the terminal.

[0539] S1112, AMF determines to switch the terminal to the second access network device based on the second switching time information.

[0540] For a detailed description of steps S1110 - S1112 , please refer to the relevant descriptions in the above steps S807 - S809 .

[0541] S1113, SMF determines to update access network tunnel information corresponding to one or more sessions of the terminal based on the second switching time information.

[0542] Exemplarily, the access network tunnel information allocated by SMF to the terminal belongs to the access network tunnel information of session granularity. SMF can determine that the identifier of the current target access network device of the terminal is the identifier of the second access network device based on the second switching time information (refer to Table 1); and based on the seventh corresponding relationship stored locally, determine the first access network tunnel information corresponding to the identifier of the first session of the terminal and the identifier of the second access network device; SMF updates the access network tunnel information corresponding to the first session stored locally to the first access network tunnel information. Alternatively, SMF can also update the access network tunnel information corresponding to one or more sessions of the terminal based on the second information shown in Table 9 above.

[0543] S1114, SMF sends a second message to UPF.

[0544] For the description of the second message, please refer to the relevant description in S406 above, which will not be described in detail here.

[0545] S1115, the second access network device communicates with the UPF based on the core network tunnel information and access network tunnel information of the terminal.

[0546] In some other possible implementations, the communication method provided in the present application may also include S1101-S1113, S1116-S1117, and S1115.

[0547] S1116, SMF sends third information to UPF, where the third information includes service time and access network tunnel information corresponding to the identifier of the terminal session.

[0548] Accordingly, the UPF receives the third information.

[0549] Exemplarily, the third information may include the same data as the second information shown in Table 9 above. It should be noted that the session identifier in the third information sent by SMF to UPF may be the PDU session ID or N4session ID of the session.

[0550] S1117, UPF updates the access network tunnel information of the terminal session based on the third information.

[0551] Specifically, the UPF updates the access network tunnel information of the session whose service time corresponds to the current time based on the second information, and performs step S1115 after step S1117. For example, the UPF determines the service time corresponding to the current moment, and updates the access network tunnel information of the session (one or more) corresponding to the service time to the access network tunnel information corresponding to the session and corresponding to the service time. For details, please refer to the relevant description of the SMF updating the access network tunnel information of the terminal session based on Table 9 in step S1013 above.

[0552] In a possible implementation, after the SMF allocates corresponding access network tunnel information to multiple access network device service terminals in step S1109, the access network tunnel information allocated by the SMF to the access network device service terminal may not be sent to the corresponding access network device through the AMF. Instead, the UPF sends the access network tunnel information allocated by the SMF to the access network device service terminal to the corresponding access network device after step S1114 or after step S1117.

[0553] In addition, the present application also provides a communication device, including a device for executing Figure 4-Figure 11 A unit that uses any communication method.

[0554] The present application also provides a communication device, including a processor, wherein the processor is configured to execute Figure 4-Figure 11 Any communication method.

[0555] The present application also provides a communication system, including an access and mobility management function network element, a first access network device, and a second access network device, wherein the access and mobility management function network element is used to perform Figure 4 The steps performed by the access and mobility management function network element in any one of the communication methods, the first access network device is used to perform Figure 4 The steps performed by the first access network device in any one of the communication methods, the second access network device is used to perform Figure 4 The steps performed by the first access network device in any one of the communication methods.

[0556] The present application also provides a communication system, including an access and mobility management function network element, a first access network device, and a second access network device, wherein the access and mobility management function network element is used to perform Figure 6 The steps performed by the access and mobility management function network element in any one of the communication methods, the first access network device is used to perform Figure 6 The steps performed by the first access network device in any one of the communication methods, the second access network device is used to perform Figure 6 The steps performed by the first access network device in any one of the communication methods.

[0557] The present application also provides a communication system, including an access and mobility management function network element, a session management function network element, a first access network device, and a second access network device, wherein the access and mobility management function network element is used to perform Figure 7 The steps performed by the access and mobility management function network element in any one of the communication methods, the session management function network element is used to perform Figure 7 The steps performed by the session management function network element in any one of the communication methods, the first access network device is used to perform Figure 7 The steps performed by the first access network device in any one of the communication methods, the second access network device is used to perform Figure 7 The steps performed by the first access network device in any one of the communication methods.

[0558] The present application also provides a communication system, including an access and mobility management function network element, a session management function network element, a first access network device, and a second access network device, wherein the access and mobility management function network element is used to perform Figure 8 The steps performed by the access and mobility management function network element in any one of the communication methods, the session management function network element is used to perform Figure 8 The steps performed by the session management function network element in any one of the communication methods, the first access network device is used to perform Figure 8 The steps performed by the first access network device in any one of the communication methods, the second access network device is used to perform Figure 8The steps performed by the first access network device in any one of the communication methods.

[0559] The present application also provides a communication system, including an access and mobility management function network element, a session management function network element, a first access network device, and a second access network device, wherein the access and mobility management function network element is used to perform Fig. 9 The steps performed by the access and mobility management function network element in any one of the communication methods, the session management function network element is used to perform Fig. 9 The steps performed by the session management function network element in any one of the communication methods, the first access network device is used to perform Fig. 9 The steps performed by the first access network device in any one of the communication methods, the second access network device is used to perform Fig. 9 The steps performed by the first access network device in any one of the communication methods.

[0560] The present application also provides a communication system, including an access and mobility management function network element, a session management function network element, a user plane function network element, a first access network device, and a second access network device, wherein the access and mobility management function network element is used to perform Fig.10 The steps performed by the access and mobility management function network element in any one of the communication methods, the session management function network element is used to perform Fig.10 The steps performed by the session management function network element in any one of the communication methods, the user plane function network element is used to perform Fig.10 The steps performed by the user plane function network element in any one of the communication methods, the first access network device is used to perform Fig.10 The steps performed by the first access network device in any one of the communication methods, the second access network device is used to perform Figure 7 The steps performed by the first access network device in any one of the communication methods.

[0561] The present application also provides a communication system, including an access and mobility management function network element, a session management function network element, a user plane function network element, a first access network device, and a second access network device, wherein the access and mobility management function network element is used to perform Fig.11 The steps performed by the access and mobility management function network element in any one of the communication methods, the session management function network element is used to perform Fig.11 The steps performed by the session management function network element in any one of the communication methods, the user plane function network element is used to perform Fig.11 The steps performed by the user plane function network element in any one of the communication methods, the first access network device is used to perform Fig.11 The steps performed by the first access network device in any one of the communication methods, the second access network device is used to perform Fig.11The steps performed by the first access network device in any one of the communication methods.

[0562] In several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods may be implemented in other ways.

[0563] The present application also provides a computer program, which is used to implement the communication method provided by the present application. Figure 4-Figure 11 The operations and / or processing performed by the AMF shown.

[0564] The present application also provides a computer program, which is used to implement the communication method provided by the present application. Figure 4-Figure 11 The operations and / or processes performed by the SMF shown.

[0565] The present application also provides a computer program, which is used to implement the communication method provided by the present application. Figure 4-Figure 11 The operations and / or processing performed by the UPF are shown.

[0566] The present application also provides a computer program, which is used to implement the communication method provided by the present application. Figure 4-Figure 11 The operations and / or processing performed by the first access network device or the second access network device shown.

[0567] The present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer code, and when the computer code is executed on a computer, the computer executes the communication method provided by the present application. Figure 4-Figure 11 The operations and / or processing performed by the AMF shown.

[0568] The present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer code, and when the computer code is executed on a computer, the computer executes the communication method provided by the present application. Figure 4-Figure 11 The operations and / or processes performed by the SMF shown.

[0569] The present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer code, and when the computer code is executed on a computer, the computer executes the communication method provided by the present application. Figure 4-Figure 11 The operations and / or processing performed by the UPF shown.

[0570] The present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer code, and when the computer code is executed on a computer, the computer executes the communication method provided by the present application. Figure 4-Figure 11 The operations and / or processing performed by the first access network device or the second access network device shown.

[0571] The present application also provides a computer program product, which includes a computer code or a computer program. When the computer code or the computer program is run on a computer, the communication method provided by the present application is performed by Figure 4-Figure 11 The operations and / or processing performed by the AMF shown are performed.

[0572] The present application also provides a computer program product, which includes a computer code or a computer program. When the computer code or the computer program is run on a computer, the communication method provided by the present application is performed by Figure 4-Figure 11 The operations and / or processes performed by the illustrated SMF are executed.

[0573] The present application also provides a computer program product, which includes a computer code or a computer program. When the computer code or the computer program is run on a computer, the communication method provided by the present application is performed by Figure 4-Figure 11 The operations and / or processing performed by the UPF shown are executed.

[0574] The present application also provides a computer program product, which includes a computer code or a computer program. When the computer code or the computer program is run on a computer, the communication method provided by the present application is performed by Figure 4-Figure 11 The operations and / or processes shown to be performed by the first access network device or the second access network device are executed.

[0575] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A communication method, characterized in that: Applied to a second access network device, the method comprises: Receiving a handover request message from the first access network device, where the handover request message is used to request handover of the terminal to the second access network device; Communicate with the user plane function network element based on the switching request message and the core network tunnel information of the terminal stored in the second access network device.

2. The method according to claim 1, characterized in that Before receiving the handover request message from the first access network device, the method further includes: Receive core network tunnel information of the terminal, and store the core network tunnel information.

3. The method according to claim 1 or 2, characterized in that: After receiving the handover request message from the first access network device, the method further includes: If the second access network device does not store the core network tunnel information of the terminal, or the second access network device does not allocate access network tunnel information to the terminal, a path switching message is sent to the access and mobility management function network element, and the path switching message is used to switch the path corresponding to the terminal.

4. The method according to any one of claims 1 to 3, characterized in that After receiving the handover request message from the first access network device, the method further includes: If the second access network device has stored the core network tunnel information of the terminal and the second access network device has allocated the access network tunnel information to the terminal, a path switching message is not sent to the access and mobility management function network element, and the path switching message is used to switch the path corresponding to the terminal.

5. The method according to any one of claims 1 to 4, characterized in that The method further comprises: Allocating the access network tunnel information to the terminal; The access network tunnel information is sent to an access and mobility management function network element.

6. The method according to any one of claims 1 to 5, characterized in that Before receiving the handover request message from the first access network device, the method further includes: receiving a first request, where the first request is used to request allocation of access network tunnel information for the terminal; Allocating access network tunnel information to the terminal based on the first request; A first response is sent, where the first response carries the access network tunnel information.

7. The method according to claim 6, characterized in that The first request comes from the first access network device, and the sending of the first response includes: The first response is sent to the first access network device, where the first response includes the access network tunnel information and first indication information, and the first indication information is used to instruct the first access network device to send the access network tunnel information to the access and mobility management function network element.

8. The method according to any one of claims 1 to 7, characterized in that The terminal is a stationary terminal.

9. A communication method, characterized in that: Applied to a first access network device, the method includes: Determine, based on first switching time information of the terminal, to switch the terminal to a second access network device, where the first switching time information includes a time when at least one access network device serves the terminal, and the at least one access network device includes the second access network device; A switching request message is sent to the second access network device, where the switching request message is used to request that the terminal be switched to the second access network device.

10. The method according to claim 9, characterized in that The method further comprises: determining the first switching time information based on the access time of the terminal to the at least one access network device in the satellite operation cycle; or, determining the first switching time information based on the location and ephemeris information of the terminal; or, The first switching time information is received from an access and mobility management function network element.

11. The method according to claim 9 or 10, characterized in that: The satellite corresponding to the at least one access network device and the satellite corresponding to the first access network device belong to the same constellation; or, A satellite corresponding to the at least one access network device has a direct and / or indirect inter-satellite link connection with a satellite corresponding to the first access network device; or, The coverage area of ​​each of the at least one access network device includes the location of the terminal.

12. The method according to any one of claims 9 to 11, characterized in that: Before sending the switching request message to the second access network device, the method further includes: Requesting the second access network device to allocate access network tunnel information to the terminal; Receiving the access network tunnel information from the second access network device; The access network tunnel information is sent to an access and mobility management function network element.

13. The method according to claim 12, characterized in that The requesting the second access network device to allocate access network tunnel information to the terminal comprises: Request the second access network device to allocate access network tunnel information for the first session of the terminal.

14. The method according to any one of claims 8 to 13, characterized in that: Before sending the switching request message to the second access network device, the method further includes: Requesting the user plane function network element to allocate core network tunnel information for the terminal; Receiving first core network tunnel information from the user plane function network element, where the first core network tunnel information corresponds to the second access network device; Send the first core network tunnel information to the second access network device.

15. The method according to any one of claims 9 to 14, characterized in that: The terminal is a stationary terminal.

16. A communication method, characterized in that: The method is applied to an access and mobility management function network element, and the method comprises: Determine, based on second switching time information of the terminal, to switch the terminal from the first access network device to the second access network device, where the second switching time information includes a time when at least one access network device serves the terminal, and the at least one access network device includes the second access network device; A first message is sent to a session management function network element, where the first message is used to update access network tunnel information of the terminal.

17. The method according to claim 16, characterized in that The first message includes one or more of the following: Access network tunnel information allocated by the second access network device to the terminal; An identifier of the second access network device; The identifier of the first session of the terminal.

18. The method according to claim 17, characterized in that When the first message includes the identifier of the first session, the first message is specifically used to update the access network tunnel information of the first session.

19. The method according to any one of claims 16 to 18, characterized in that: The method further comprises: The access and mobility management function network element determines the second switching time information based on the access time of the terminal accessing the at least one access network device in the satellite operation cycle; or, The access and mobility management function network element determines the second switching time information based on the location and ephemeris information of the terminal.

20. The method according to any one of claims 16 to 19, characterized in that Before determining to switch the terminal from the first access network device to the second access network device based on the second switching time information of the terminal, the method further includes: Receive access network tunnel information allocated by the second access network device to the terminal.

21. The method according to any one of claims 16 to 20, characterized in that: The coverage of the at least one access network device includes the location of the terminal.

22. The method according to any one of claims 16 to 21, characterized in that The terminal is a stationary terminal.

23. A communication method, characterized in that: Applied to a session management function network element, the method comprises: receiving a first message from an access and mobility management function network element, where the first message is used to update access network tunnel information of the terminal, and the first message includes an identifier of a second access network device; Allocating access network tunnel information to the terminal based on the identifier of the second access network device; The allocated access network tunnel information is sent to a user plane function network element, where the allocated access network tunnel information is used by the user plane function network element to update the access network tunnel information of the terminal.

24. The method according to claim 23, characterized in that The method further comprises: Send the core network tunnel information of the terminal to the second access network device.

25. The method according to claim 23 or 24, characterized in that The method further comprises: Send the allocated access network tunnel information to the second access network device.

26. A communication method, characterized in that: Applied to a session management function network element, the method comprises: receiving access network tunnel information allocated to the terminal by the second access network device from the access and mobility management function network element; receiving a first message from the access and mobility management function network element, where the first message is used to update the access network tunnel information of the terminal, and the first message includes an identifier of the second access network device; Based on the identifier of the second access network device, the access network tunnel information allocated by the second access network device to the terminal is sent to the user plane function network element, and the access network tunnel information is used by the user plane function network element to update the access network tunnel information of the terminal.

27. The method according to claim 26, before receiving the first message from the access and mobility management function network element, further comprising: Send the core network tunnel information of the terminal to the second access network device.

28. A communication system, characterized in that: The system includes a first access network device, a second access network device, and an access and mobility management function network element; Wherein, the second access network device is used to perform the method according to any one of claims 1 to 8; The first access network device is used to perform the method according to any one of claims 9 to 15; The access and mobility management function network element is used to execute the method according to any one of claims 16-22.

29. The system according to claim 28, characterized in that The system also includes a session management function network element; The session management function network element is used to execute the method according to any one of claims 23 to 25; or, The session management function network element is used to execute the method according to claim 26 or 27.

30. A communication device, characterized in that: Comprising means for performing the method as claimed in any one of claims 1 to 27.

31. A communication device, characterized in that: The device comprises a processor, wherein the processor is used to read and execute a computer program stored in a memory to implement the method according to any one of claims 1 to 27.

32. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store a computer program. When the computer program is executed, the method according to any one of claims 1 to 27 is executed.

33. A computer program, characterized in that When the computer program is executed, the method of any one of claims 1 to 27 is performed.

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