Communication method, communication apparatus, communication system, and storage medium

Abstract

Disclosed in the embodiments of the present application are a communication method, a communication apparatus, a communication system, and a storage medium, applicable to the technical field of communications, and used for implementing session establishment between terminal devices. The method in the embodiments of the present application comprises: receiving a first request message, the first request message comprising identification information of a first network element, and the first network element being deployed in a first non-terrestrial network device; and acquiring path status information on the basis of the identification information of the first network element, the path status information being used for indicating a path status between the first network element and a second network element, the second network element being deployed in a second non-terrestrial network device, and both the first network element and the second network element being user plane function network elements. According to the embodiments of the present application, network elements deployed in non-terrestrial devices are used to query an inter-satellite path, so that whether or not to enable UE-SAT-UE communication can be determined on the basis of the reachability of the inter-satellite path, thereby preventing the problem of being unable to query the reachability of an inter-satellite path because external interfaces cannot be standardized.

Description

Communication methods, communication devices, communication systems and storage media

[0001] This application claims priority to Chinese Patent Application No. 202411401993.3, filed with the State Intellectual Property Office of China on September 30, 2024, entitled "Communication Method, Communication Device, Communication System and Storage Medium", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a communication method, communication device, communication system and storage medium. Background Technology

[0003] The communication method in which user equipment (UE) communicates via inter-satellite links is called UE-SAT-UE communication. In existing schemes, the proxy-call session control function (P-CSCF) network element determines whether to enable UE-SAT-UE communication based on whether the calling UE and the called UE access the network via satellite.

[0004] In satellite networks, there exist opposing orbits. Satellites in opposing orbits may be spatially close for a period of time, but their directions of motion are opposite. Due to the high relative speeds between satellites in opposing orbits, it is difficult to establish inter-satellite links. Therefore, they usually cannot communicate with each other via inter-satellite links, or the inter-satellite links require a long detour, resulting in excessive latency in calls between UEs. Therefore, the P-CSCF or session management function (SMF) network element needs to query external systems, such as the satellite routing subsystem, to determine whether direct communication based on inter-satellite links is supported between two satellites.

[0005] However, P-CSCF or SMF network elements belong to different domains and have different standards developed by different organizations, making it difficult to standardize their interfaces. Even if standardized, it is difficult to promote and implement them across different products. When the 3rd Generation Partnership Project (3GPP) system and the external system belong to different vendors, P-CSCF or SMF network elements often cannot obtain the reachability of inter-satellite links, and therefore cannot determine the communication links between UEs based on the reachability of inter-satellite links. Summary of the Invention

[0006] This application provides a communication method, communication device, communication system, and storage medium. By querying inter-satellite paths through network elements deployed on non-terrestrial network equipment, the system determines whether to enable UE-SAT-UE communication based on the reachability of the inter-satellite paths, thereby avoiding the problem of being unable to query inter-satellite path reachability due to the lack of standardization of external interfaces.

[0007] The first aspect of this application provides a communication method. Optionally, the executing entity of this method can be an SMF network element. The SMF network element can be a network device, a component or device applied to the network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of the network device. Taking the SMF network element as a network device as an example, in this method, the SMF network element receives a first request message, which includes the identification information of the first network element. The first network element is deployed on a first non-terrestrial network device. The SMF network element obtains path status information based on the identification information of the first network element. The path status information is used to indicate the path status between the first network element and a second network element, which is deployed on a second non-terrestrial network device. Both the first network element and the second network element are user plane function network elements.

[0008] Based on the first aspect of this application, the SMF network element obtains path status information from the onboard UPF, thus eliminating the need for the SMF network element to query external systems and avoiding the problem of being unable to query the path status of inter-satellite links due to the lack of standardization of external interfaces.

[0009] Based on the first aspect of this application, in some possible implementations, the SMF network element will also receive a path status notification message, which includes the path status between the second network element and multiple network elements. The SMF network element determines the path status information based on the identification information of the first network element and the path status notification message.

[0010] In this embodiment, the SMF network element can obtain the path status between the second network element and multiple other network elements by receiving path status notification messages. Among these multiple network elements, the first network element is included. Therefore, based on the identification information of the first network element, the SMF network element can determine the path status between the first network element and the second network element from the path status communication message, i.e., the path status information. This eliminates the need for the SMF network element to query external systems to obtain the path status, avoiding the problem of being unable to query the path status of inter-satellite links due to the lack of standardization of external interfaces.

[0011] Based on the first aspect of this application, in some possible implementations, the SMF network element sends a query request message, which includes identification information of a first network element used to obtain the path status between the first network element and the second network element. The SMF network element receives a first response message, which is a response to the query request message and is used to indicate the path status information.

[0012] In this embodiment, the SMF network element sends a query request message, enabling the recipient of the message to query the path status between the first and second network elements based on the identifier of the first network element carried in the query request message. The SMF network element receives a first response message and obtains the path status information from it, thus avoiding the need to query external systems and preventing the inability to query the path status of inter-satellite links due to the lack of standardization of external interfaces.

[0013] Based on the first aspect of this application, in some possible implementations, the SMF network element may also send a second response message, which is a response message to the first request message; wherein, if the path status information indicates that the path status between the first network element and the second network element is available, the second response message includes the tunnel information of the second network element; or, if the path status information indicates that the path status between the first network element and the second network element is unavailable, the second response message includes a path unavailable indication.

[0014] In this embodiment of the application, the SMF network element enables the recipient of the second response message to obtain the path status indicated by the second response message by sending the second response message.

[0015] Based on the first aspect of this application, in some possible implementations, the first request message further includes tunnel information of the first network element and the Internet Protocol (IP) address of the first terminal device. The SMF network element also sends a first traffic splitting rule, which instructs the second network element to send the first data packet to the first network element according to the tunnel information of the first network element. The destination address of the first data packet is the IP address of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services to the first terminal device, and the second network element provides services to the second terminal device.

[0016] In this embodiment of the application, the SMF network element establishes an inter-satellite link by instructing the first diversion rule, which enables the second network element to transmit data packets based on the first diversion rule.

[0017] Based on the first aspect of this application, in some possible implementations, when the path status information indicates that the path status between the first network element and the second network element is available, the SMF network element sends the first traffic splitting rule.

[0018] In this embodiment of the application, the SMF network element sends the first traffic splitting rule only when the path is available, thus avoiding the establishment of inter-satellite links when the path is unavailable, which would prevent the session from proceeding.

[0019] Based on the first aspect of this application, in some possible implementations, the first request message further includes tunnel information of the first network element and Internet Protocol (IP) identification information of the first terminal device. The SMF network element sends a first message, which includes indication information and a first traffic splitting rule. The indication information is used to instruct the second network element to perform traffic splitting according to the first traffic splitting rule when the path status between the first network element and the second network element is available. The first traffic splitting rule is used to instruct the second network element to send the first data packet to the first network element through the tunnel information of the first network element. The destination address of the first data packet is the identification information of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services for the IMS session or IMS connection of the first terminal device, and the second network element provides services for the second terminal device. When the path status is available, the SMF network element receives a successful establishment indication; or, when the path status is unavailable, the SMF network element receives a path unavailable indication.

[0020] In this embodiment, the SMF network element sends an indication message simultaneously with the first traffic splitting rule. This allows the receiver of the first message to directly establish an inter-satellite path when the path is available, i.e., directly use the first traffic splitting rule for splitting, or to return a path unavailable indication when the path is unavailable. Therefore, the SMF network element does not need to obtain the path status, reducing signaling overhead.

[0021] Based on the first aspect of this application, in some possible implementations, the SMF network element will also send a second traffic splitting rule, which is used to instruct the second network element to send the first data packet to the session anchor point. The destination address of the first data packet is the IP address of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services to the first terminal device, and the second network element provides services to the second terminal device. The session anchor point is deployed on the first terrestrial network.

[0022] In this embodiment, the SMF network element sends a second traffic splitting rule, enabling the receiver of the second traffic splitting rule to transmit data packets via a terrestrial path based on the second traffic splitting rule. Therefore, the receiver of the second traffic splitting rule can switch transmission paths and use terrestrial paths when inter-satellite paths are unavailable, thereby ensuring session continuity and preventing session interruption.

[0023] Based on the first aspect of this application, in some possible implementations, when the path status information indicates that the path status between the first network element and the second network element is unavailable, the SMF network element sends a second traffic splitting rule.

[0024] In this embodiment of the application, the SMF network element sends a second diversion rule when the path is unavailable, thereby enabling the establishment of a path through the ground session anchor network element for the call between the first terminal device and the second terminal device when the inter-satellite path is unavailable, thus preventing session interruption.

[0025] Based on the first aspect of this application, in some possible implementations, the SMF network element will also send a first instruction message, which is used to instruct the second network element to use a first traffic splitting rule or a second traffic splitting rule according to the path status information.

[0026] In this embodiment of the application, the SMF network element sends a first indication message, enabling the receiver of the first indication message to select between an inter-satellite path or a ground path based on the path status information, thereby ensuring the continuity of the session and preventing session interruption.

[0027] Based on the first aspect of this application, in some possible implementations, the SMF network element sends a first indication message when sending the first and second traffic splitting rules. This enables the SMF network element to establish two paths for the call between the first and second terminal devices: a terrestrial path and an inter-satellite path, and instructs the receiver to dynamically select either the inter-satellite path or the terrestrial path based on the path status. For example, when the inter-satellite path is unavailable, the terrestrial path can be automatically selected, thereby ensuring session continuity and preventing session interruption.

[0028] Based on the first aspect of this application, in some possible implementations, the SMF network element will also receive first information, which is used to indicate that the path status between the first network element and the second network element has changed, or to indicate the switching of the transmission path between the first network element and the second network element; the SMF network element sends a first diversion rule or a second diversion rule according to the first information.

[0029] In this embodiment of the application, when the path state between the first network element and the second network element changes, the SMF network element sends a first or second traffic splitting rule to indicate the switching of the transmission path, thereby ensuring the continuity of the session and preventing session interruption when the path state between the first network element and the second network element changes.

[0030] Based on the first aspect of this application, in some possible implementations, the SMF network element will also receive second information, which includes service flow information between the second terminal device and the terrestrial access gateway. The terrestrial access gateway is deployed in the second terrestrial network, and data is transmitted between the terrestrial access gateway and the second network element through a session anchor. In response to the second information, the SMF network element sends a third traffic splitting rule and a fourth traffic splitting rule. The third traffic splitting rule instructs the second network element to send a third data packet to the session anchor. The third data packet is a data packet sent by the second terminal device to the terrestrial access gateway. The fourth traffic splitting rule instructs the second network element to send a fourth data packet from the session anchor to the second terminal device. The fourth data packet is a data packet sent by the terrestrial access gateway to the second terminal device.

[0031] In this embodiment of the application, the SMF network element sends a third and a fourth traffic splitting rule, thereby enabling the recipient of the third and fourth traffic splitting rules to transmit data packets through the terrestrial access gateway.

[0032] Based on the first aspect of this application, in some possible implementations, the SMF network element will also receive third information, which indicates a change in the path state between the first network element and the second network element. If, according to the third information, the path state between the first network element and the second network element changes from an unavailable state to an available state, a path available indication is sent in response to the third information; or, if, according to the third information, the path state between the first network element and the second network element changes from an available state to an unavailable state, a path unavailable indication is sent in response to the third information.

[0033] In this embodiment of the application, when the path state between the first network element and the second network element changes, the SMF network element sends a path availability indication or a path unavailability indication, thereby enabling the recipient of the indication to determine whether the inter-satellite link is available based on the path availability indication or the path unavailability indication.

[0034] Based on the first aspect of this application, in some possible implementations, the first request message also includes the IP address of the second terminal device and the IP address of the terrestrial access gateway. The SMF network element also sends a third traffic splitting rule, which instructs the second network element to send a third data packet from the session anchor to the second terminal device. The third data packet is a data packet sent by the terrestrial access gateway to the second terminal device. The terrestrial access gateway is deployed in the second terrestrial network, and the session anchor is deployed in the first terrestrial network. The terrestrial access gateway and the second network element transmit the third data packet through the session anchor.

[0035] In this embodiment of the application, since the first request message also includes the IP address of the second terminal device and the IP address of the terrestrial access gateway, the SMF network element can send a third traffic splitting rule, so that the reception of the third traffic splitting rule completes data transmission based on the terrestrial path.

[0036] A second aspect of this application provides a communication method. Optionally, the executing entity of this method may be a first proxy-call session control function (P-CSCF). The first P-CSCF may be a network device, a component or device applied to the network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the network device's functions. Taking the first P-CSCF as a network device as an example, in this method, the first P-CSCF obtains the identification information of a third network element, which is deployed on a first non-terrestrial network device. The first P-CSCF sends the identification information of the third network element, which is used to obtain the transmission path between a third terminal device and a fourth terminal device. The third network element provides services to the third terminal device. The first P-CSCF receives a third response message, which is used to indicate the transmission path between the third terminal device and the fourth terminal device. The third network element is a user plane function network element or an access gateway.

[0037] Based on the second aspect of this application, the first P-CSCF can obtain and send the identification information of the third network element, so that the recipient of the identification information of the third network element can determine the transmission path between the third terminal device and the fourth terminal device based on the identification information and return it to the first P-CSCF. Therefore, the first P-CSCF does not need to query the external system, avoiding the problem that the path status of the inter-satellite link cannot be queried due to the lack of standardization of the external interface.

[0038] Based on the second aspect of this application, in some possible implementations, the third network element is a user plane function network element, and the first P-CSCF will also send a third request message, which includes the identification information of the third terminal device. The first P-CSCF receives a fourth response message, which is a response message to the third request message and includes the identification information of the third network element.

[0039] Based on the second aspect of this application, in some possible implementations, the third response message includes indication information of a first path and / or indication information of a second path. The first path is the path from the third terminal device to the fourth terminal device via a third network element and a fourth network element. The second path is the path from the third terminal device to the fourth terminal device via a session anchor or a terrestrial access gateway. The fourth network element provides services to the fourth terminal device. The session anchor is deployed in a first terrestrial network, and the terrestrial access gateway is deployed in a second terrestrial network. The session anchor includes a session anchor that provides services to the third terminal device and a session anchor that provides services to the fourth terminal device. The terrestrial access gateway includes a terrestrial access gateway that provides services to the third terminal device and a terrestrial access gateway that provides services to the fourth terminal device.

[0040] In this embodiment, the third response message may include two paths: an inter-satellite path and a ground path. The first path is an inter-satellite path, and the second path is a ground path. This allows the first P-CSCF to use either the inter-satellite path or the ground path to transmit data packets between the third and fourth terminal devices according to the instructions of the third response message. This ensures that an available path is selected between the third and fourth terminal devices, guaranteeing session continuity and preventing session interruption. When the third response message includes both a ground path and an inter-satellite path, the first P-CSCF can dynamically select either the inter-satellite path or the ground path based on the path status, thereby ensuring session continuity and preventing session interruption.

[0041] Based on the second aspect of this application, in some possible implementations, when the fourth network element is a user plane function network element, the indication information of the first path includes the tunnel information of the fourth network element and the IP address of the fourth terminal device; or, when the fourth network element is an access gateway, the indication information of the first path includes the IP address of the fourth network element; when the second path is a path between the third terminal device and the fourth terminal device through a terrestrial access network element, the indication information of the second path includes the IP address of the terrestrial access gateway; or, when the second path is a path between the third terminal device and the third terminal device through a session anchor point, the indication information of the second path includes the IP address of the fourth terminal device.

[0042] Based on the second aspect of this application, in some possible implementations, the first P-CSCF may also send call signaling to the terminal device, the call signaling being used to indicate the first path and / or the second path.

[0043] The call signaling includes any one of the following: the IP address of the fourth terminal device, the IP address of the terrestrial access gateway, wherein the terrestrial access gateway is the terrestrial access gateway that provides services to the third terminal device, and the IP address of the third network element.

[0044] Scenario A: When the third response message indicates the first path and the third network element is a user plane function network element, the call signaling includes the IP address of the fourth terminal device. In this case, the third terminal device directly sends the session data packet to the fourth terminal device using the fourth terminal device's IP address.

[0045] Scenario B: When the fourth response message indicates the first path and the third network element is an access gateway, the call signaling includes the IP address of the third network element. In this case, the third terminal device first sends the session data packet destined for the fourth terminal device to the third network element, and then the third network element sends the session data packet to the fourth terminal device.

[0046] Scenario C: When the fourth response message indicates the second path, and the second path is the path between the third terminal device and the fourth terminal device through the session anchor, the call signaling includes the IP address of the fourth terminal device. In this case, the third terminal device sends session data packets directly to the fourth terminal device using the fourth terminal device's IP address.

[0047] Scenario D: When the fourth response message indicates the second path, and the second path is the path between the third terminal device and the fourth terminal device via a terrestrial access gateway, the call signaling includes the IP address of the terrestrial access gateway, which is the terrestrial access gateway providing services to the third terminal device. In this case, the third terminal device first sends the session data packets intended for the fourth terminal device to the terrestrial access gateway serving the third terminal device, and then the terrestrial access gateway forwards the session data packets to the fourth terminal device.

[0048] When the fourth response message simultaneously indicates the first path and the second path, the call signaling includes the information included in situation A or situation B and the information corresponding to situation C or situation D, respectively.

[0049] In this embodiment of the application, the first P-CSCF can determine the call signaling to be sent to the terminal device according to the path indication of the third response message, so that the terminal can send session information through the path indicated by the third response message, avoid sending messages through unavailable paths, thereby ensuring the continuity of the session and preventing session interruption.

[0050] Based on the second aspect of this application, in some possible implementations, the first P-CSCF will also receive third information, which indicates a change in the path status of the first or second path. The first P-CSCF will also send fourth information, which indicates switching the first path to the second path, or vice versa.

[0051] In this embodiment of the application, the first P-CSCF sends a fourth message to the second P-CSCF to instruct the second P-CSCF to switch paths, thereby enabling the session path to be switched to an available path when the path status changes, ensuring session continuity and preventing session interruption.

[0052] Based on the second aspect of this application, in some possible implementations, when the fourth information is used to indicate switching the first path to the second path, and the second path is a path between the third terminal device and the fourth terminal device via a terrestrial access gateway, the fourth information includes the IP address of the terrestrial access gateway, which is a terrestrial access gateway providing services to the third terminal device and is deployed in a second terrestrial network; or, when the fourth information is used to indicate switching the first path to the second path, and the second path is a path between the third terminal device and the fourth terminal device via a session anchor point, the fourth information includes the IP address of the third terminal device; or, when the fourth information indicates switching the second path to the first path and the third network element is a user plane function network element, the fourth information includes the tunnel information of the third network element and the IP address of the third terminal device, and the third network element provides services to the third terminal device; or, when the fourth information indicates switching the second path to the first path and both the third network element and the fourth network element are access gateways, the fourth information includes the IP address of the third network element.

[0053] In this embodiment of the application, the first P-CSCF sends the IP address information required by the target path to the second P-CSCF in the fourth information, thereby enabling the second P-CSCF to switch the communication path to the target path and thus ensuring that the session is not interrupted.

[0054] Based on the second aspect of this application, in some possible implementations, the first P-CSCF may also send second instruction information, which includes address information required by the third terminal device to send session data to the fourth terminal device through a target path, the target path being either the first path or the second path.

[0055] In the case where the target path is as described in scenario A above, the second instruction information is used to instruct the third terminal device to send the session data packet directly to the fourth terminal device through the IP address of the fourth terminal device.

[0056] When the target path is case B above, the second instruction information is used to instruct the third terminal device to send the session data packet destined for the fourth terminal device to the third network element first, and then the third network element sends the session data packet to the fourth terminal device.

[0057] When the target path is case C as described above, the second instruction information is used to instruct the third terminal device to send the session data packet directly to the fourth terminal device through the IP address of the fourth terminal device.

[0058] When the target path is case D as described above, the second indication information is used to instruct the third terminal device to first send the session data packets destined for the fourth terminal device to the ground access gateway serving the third terminal device, and then the ground access gateway will send the session data packets to the fourth terminal device.

[0059] In this embodiment of the application, the first P-CSCF sends a second instruction message to instruct the third terminal device to switch paths. Thus, when the path status changes, the third terminal device can switch the session data to the target path according to the second instruction message, which can ensure the continuity of the session and prevent session interruption.

[0060] Based on the second aspect of this application, in some possible implementations, the first P-CSCF will also send fifth information, which includes service flow information between the third terminal device and the terrestrial access gateway.

[0061] In this embodiment of the application, during the path switching process, the first P-CSCF instructs the SMF network element to switch the inter-satellite path to the ground path by sending the fifth message.

[0062] Based on the second aspect of this application, in some possible implementations, the call signaling further includes third indication information, which is used to instruct a third terminal device to transmit data using the first path or the second path according to the path status of the first path and / or the second path.

[0063] In this embodiment of the application, when the call signaling simultaneously indicates the first path and the second path, the first P-CSCF carries third indication information in the call signaling, thereby enabling the terminal device to use the first path or the second path to transmit data according to the path status of the first path and / or the second path, so that the terminal device can select the optimal path to transmit data.

[0064] Based on the second aspect of this application, in some possible implementations, the call signaling further includes a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0065] In this embodiment of the application, the first P-CSCF carries a path selection policy in the call signaling, thereby enabling the terminal device to transmit data using a first path or a second path according to the path selection policy.

[0066] Based on the second aspect of this application, in some possible implementations, the call signaling further includes fourth indication information, which is used to instruct the third terminal device to perform path monitoring to obtain the path status of the first path and / or the second path.

[0067] Based on the second aspect of this application, in some possible implementations, the third network element is an access gateway, the third response message includes information about a third path and / or a fourth path, the information about the third path includes the IP address of the fourth network element, the fourth network element is deployed on a second non-terrestrial network device, the fourth network element is an access gateway, the fourth network element provides services to a fourth terminal device, the information about the fourth path includes the IP address of a terrestrial access gateway, the terrestrial access gateway is deployed on a second terrestrial network, the third path is the path from the third terminal device to the fourth terminal device through the third network element and the fourth network element, and the fourth path is the path from the third terminal device to the fourth terminal device through the third network element and the terrestrial access gateway.

[0068] Based on the second aspect of this application, in some possible implementations, the first P-CSCF may also send a fifth instruction message, which is used to instruct the third network element to use the third path or the fourth path to transmit data according to the path status of the third path and / or the fourth path.

[0069] Based on the second aspect of this application, in some possible implementations, the first P-CSCF will also send a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold. The first P-CSCF will also send a sixth indication message, which is used to instruct the third network element to monitor the path status of the third path and / or the fourth path.

[0070] Based on the second aspect of this application, in some possible implementations, the first P-CSCF will also determine the transmission path based on path status information, which is determined based on the identification information of the third network element. The path status information is used to indicate the path status between the third network element and the fourth network element, and the fourth network element provides services to the fourth terminal device.

[0071] A third aspect of this application provides a communication method. Optionally, the execution entity of this method may be a second P-CSCF, which may be a network device, a component or device applied to the network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of the network device. Taking the second P-CSCF as a network device as an example, in this method, the second P-CSCF receives the identification information of a third network element. The identification information of the third network element is used to obtain the transmission path between the third terminal device and the fourth terminal device. The third network element provides services to the third terminal device. The third network element is a user plane function network element or an access gateway, and the third network element is deployed on the first non-terrestrial network device. The second P-CSCF sends a third response message, which is used to indicate the transmission path between the third terminal device and the fourth terminal device.

[0072] Based on the third aspect of this application, the second P-CSCF determines the transmission path by identifying the third network element, thereby eliminating the need to query external systems and avoiding the problem of being unable to query the path status of inter-satellite links due to the lack of standardization of external interfaces.

[0073] Based on a third aspect of this application, in some possible implementations, the second P-CSCF sends a second request message, which includes the identification information of the third network element. The second P-CSCF receives a fourth response message, which is a response to the second request message. The fourth response message indicates the path establishment status between the third and fourth network elements, whereby the fourth network element provides services to the fourth terminal device, and the fourth network element is deployed on the second non-terrestrial network equipment. The second P-CSCF determines the transmission path between the third and fourth terminal devices based on the path establishment status between the third and fourth network elements.

[0074] In this embodiment, the second P-CSCF determines the path establishment status between the third and fourth network elements based on the path status between the third and fourth network elements. This allows it to directly indicate the path establishment status to the recipient of the fourth response message, improving session establishment efficiency. Based on the third aspect of this application, in some possible embodiments, the third response message includes indication information for a first path or a second path. The first path is the path from the third terminal device to the fourth terminal device via the third and fourth network elements. The second path is the path from the third terminal device to the fourth terminal device via a session anchor point or a terrestrial access gateway. The fourth network element provides services to the fourth terminal device. The session anchor point is deployed in the first terrestrial network, and the terrestrial access gateway is deployed in the second terrestrial network.

[0075] Based on the third aspect of this application, in some possible implementations, if the path establishment status between the third network element and the fourth network element is a successful establishment status, then the fourth response message includes indication information of the first path; or, if the path establishment status between the third network element and the fourth network element is a failed establishment status, then the fourth response message includes indication information of the second path.

[0076] In this embodiment of the application, the second P-CSCF determines the content carried by the fourth response message according to different path establishment states, thereby directly indicating the transmission path to the recipient of the fourth response message through the fourth response message, which improves the efficiency of session establishment.

[0077] Based on the third aspect of this application, in some possible implementations, when the third network element is a user plane function network element, the indication information of the first path includes the tunnel information of the third network element and the IP address of the fourth terminal device; or, when the third network element is an access gateway, the indication information of the first path includes the IP address of the third network element; and the indication information of the second path includes the IP address of the terrestrial access gateway.

[0078] Based on the third aspect of this application, in some possible implementations, the second P-CSCF may also send call signaling, which includes the IP address of the third terminal device and / or the IP address of the terrestrial access gateway; or, when the third network element is an access gateway, the call signaling includes the IP address of the fourth network element and / or the IP address of the terrestrial access gateway.

[0079] Based on the third aspect of this application, in some possible implementations, the second P-CSCF will also receive third information indicating a change in the path status of the first or second path. The second P-CSCF will also send fourth information indicating a switch from the first path to the second path, or a switch from the second path to the first path.

[0080] Based on the third aspect of this application, in some possible implementations, when the fourth information is used to indicate switching the first path to the second path, the fourth information includes the IP address of the terrestrial access gateway, which is deployed in the second terrestrial network; or, when the fourth information indicates switching the second path to the first path and both the third and fourth network elements are user plane function network elements, the fourth information includes the tunnel information of the third network element and the IP address of the third terminal device; or, when the fourth information indicates switching the second path to the first path and both the third and fourth network elements are access gateways, the fourth information includes the IP address of the fourth network element.

[0081] Based on the third aspect of this application, in some possible implementations, the second P-CSCF may also send a second instruction message, which is used to instruct the fourth terminal device to switch the first path to the second path or the second path to the first path.

[0082] Based on the third aspect of this application, in some possible implementations, the second P-CSCF may also send fifth information, which includes service flow information between the fourth terminal device and the terrestrial access gateway.

[0083] Based on a third aspect of this application, in some possible implementations, the call signaling further includes third indication information, which is used to instruct a fourth terminal device to transmit data using the first path or the second path according to the path status of the first path and / or the second path.

[0084] Based on the third aspect of this application, in some possible implementations, the call signaling further includes a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0085] Based on the third aspect of this application, in some possible implementations, the call signaling further includes fourth indication information, which is used to instruct a fourth terminal device to perform path monitoring to obtain the path status of the first path and / or the second path.

[0086] Based on the third aspect of this application, in some possible implementations, the third network element is an access gateway, the third response message includes information about a third path and / or a fourth path, the information about the third path includes the IP address of the third network element, the information about the fourth path includes the IP address of the terrestrial access gateway, the terrestrial access gateway is deployed in a second terrestrial network, the third path is the path between the third network element and the fourth network element, and the fourth path is the path between the fourth network element and the terrestrial access gateway.

[0087] Based on the third aspect of this application, in some possible implementations, the second P-CSCF may also send a fifth instruction message, which is used to instruct the fourth network element to use the third path or the fourth path to transmit data according to the path status of the third path and / or the fourth path.

[0088] Based on the third aspect of this application, in some possible implementations, the second P-CSCF may also send a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold. The second P-CSCF may also send a sixth indication message, which instructs the fourth network element to monitor the path status of the third path and / or the fourth path.

[0089] Based on the third aspect of this application, in some possible implementations, when both the third network element and the fourth network element are access gateways, the third response message includes path status information, and the second P-CSCF will also determine the transmission path based on the path status information. The path status information is determined based on the identification information of the third network element. The path status information is used to indicate the path status between the third network element and the fourth network element, and the fourth network element provides services to the fourth terminal device.

[0090] In this embodiment of the application, the second P-CSCF can obtain path status information from the onboard access gateway, and thus determine the transmission path based on the path status information. This eliminates the need for the second P-CSCF to query external systems, avoiding the problem of being unable to query inter-satellite path reachability due to the lack of standardization of external interfaces.

[0091] This application provides a communication method in a fourth aspect. Optionally, the execution entity of this method may be a fourth network element. The fourth network element may be a network device, a component or device applied to the network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of the network device. Taking the fourth network element as a network device as an example, in this method, the fourth network element determines path status information, which is used to indicate the path status between the third network element and the fourth network element. The third network element is deployed on a first non-terrestrial network device, and the fourth network element is deployed on a second non-terrestrial network device. Both the third and fourth network elements are user plane function network elements, or both the third and fourth network elements are access gateways. The fourth network element sends the path status information, which is used to determine the transmission path between the third terminal device and the fourth terminal device. The third network element provides services to the third terminal device, and the fourth network element provides services to the fourth terminal device.

[0092] Based on the fourth aspect of this application, the fourth network element can determine the path status between the third network element and the fourth network element. This path status is used to determine the transmission path between the third terminal device and the fourth terminal device. The transmission path can be an inter-satellite path or a terrestrial path. Thus, when selecting a transmission path between terminal devices, the path status can be used to select the path, ensuring that the session between terminal devices is transmitted through an available path.

[0093] Based on the fourth aspect of this application, in some possible implementations, the transmission path includes: a first path and / or a second path, wherein the first path is the path between the third terminal device and the fourth terminal device through the third network element and the fourth network element, and the second path is the path between the third terminal device and the fourth terminal device through a session anchor or a terrestrial access gateway, wherein the session anchor is deployed in the first terrestrial network, or the terrestrial access gateway is deployed in the second terrestrial network.

[0094] In this embodiment of the application, the fourth network element can determine the path status between the third network element and the fourth network element. The path status is used to determine the transmission path between the third terminal device and the fourth terminal device. The transmission path can be an inter-satellite path or a terrestrial path. Therefore, when selecting a transmission path between terminal devices, the path status can be used to select the path, ensuring that the session between terminal devices is transmitted through an available path.

[0095] Based on the fourth aspect of this application, in some possible implementations, the fourth network element is a user plane function network element. When the second path is a path between the third terminal device and the fourth terminal device through a session anchor point, the fourth network element will also receive a first traffic splitting rule and / or a second traffic splitting rule. The first traffic splitting rule is used to indicate the first path, and the second traffic splitting rule is used to indicate the second path. Specifically, the first traffic splitting rule instructs the second network element to send a first data packet to the first network element based on the tunnel information of the first network element. The destination address of the first data packet is the IP address of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services to the first terminal device, and the second network element provides services to the second terminal device. The second traffic splitting rule instructs the second network element to send the first data packet to the session anchor point. The destination address of the first data packet is the IP address of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services to the first terminal device, and the second network element provides services to the second terminal device. The session anchor point is deployed in the first terrestrial network.

[0096] Based on the fourth aspect of this application, in some possible implementations, the fourth network element will also receive first indication information, which is used to instruct the use of a first traffic splitting rule or a second traffic splitting rule based on the path status information. In response to the first indication information, the fourth network element determines the transmission path of the first data packet using the first traffic splitting rule or the second traffic splitting rule based on the path status information.

[0097] Based on the fourth aspect of this application, in some possible implementations, if the path status of the first path is available, the fourth network element determines the transmission path as the first path; or, if the path status of the first path is unavailable, the fourth network element determines the transmission path as the second path.

[0098] Based on the fourth aspect of this application, in some possible implementations, when the third network element and the fourth network element are access gateways, the transmission path includes: a third path and / or a fourth path, wherein the third path is the path between the third network element and the fourth network element, and the fourth path is the path between the third network element and the fourth network element through the terrestrial access gateway, wherein the terrestrial access gateway is deployed in the second terrestrial network.

[0099] In this embodiment of the application, since the transmission path includes a third path and a fourth path, the fourth network element can ensure the continuity of the session and prevent session interruption when the path state changes.

[0100] Based on the fourth aspect of this application, in some possible implementations, when the fourth network element is an access gateway, the fourth network element will also receive fifth indication information, which is used to instruct the fourth network element to use the third path or the fourth path to transmit data according to the path status of the third path and / or the fourth path.

[0101] Based on the fourth aspect of this application, in some possible implementations, the fourth network element may also receive a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0102] Based on the fourth aspect of this application, in some possible implementations, the fourth network element receives a path state subscription request, which requests the fourth network element to send a path state notification message when the path state between the fourth network element and any one of the at least one network element changes. The fourth network element sends a path state notification message, which indicates the path state between the fourth network element and any one of the at least one network element, and includes path state information.

[0103] In this embodiment of the application, the fourth network element sends a path status notification message, so that the recipient of the path status notification message does not need to query an external system, thereby avoiding the problem that the inter-satellite path reachability cannot be queried due to the lack of standardization of external interfaces.

[0104] Based on the fourth aspect of this application, in some possible implementations, the fourth network element will also receive a query request message, which includes the identification information of the third network element. The query request message is used to request a query of the path status between the third network element and the fourth network element. The fourth network element will also send a first response message, which is a response message to the query request message and is used to indicate path status information.

[0105] Based on the fourth aspect of this application, in some possible implementations, the fourth network element may also send first information, which is used to indicate that the path state between the fourth network element and any of the above-mentioned at least one network element has changed.

[0106] This application provides a fifth aspect of an information transmission method. Optionally, the subject executing this method can be a terminal device, a component or device applied to the terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the terminal device's functions. Taking a third terminal device as an example, the third terminal device receives indication information for a first path and indication information for a second path. The first path is used to directly send a second data packet to a fourth terminal device, and the second path is used to send the second data packet to the fourth terminal device through a terrestrial access gateway. The second data packet is the data packet sent by the third terminal device to the fourth terminal device. The third terminal device determines the transmission path of the second data packet based on the indication information for the first path and the second path.

[0107] Based on the fifth aspect of this application, by receiving the first path and the second path, the third terminal device can dynamically select an inter-satellite path or a ground path according to the path status, select the optimal path, and thus enable the user to have a better call experience.

[0108] Based on the fifth aspect of this application, in some possible implementations, the indication information of the first path includes the IP address of the fourth terminal device, and the indication information of the second path includes the IP address of the terrestrial access gateway, which provides services to the third terminal device.

[0109] Based on the fifth aspect of this application, in some possible implementations, the third terminal device may also receive third indication information, which is used to indicate the path of the second data packet to be determined based on the status of the first path or the second path.

[0110] Based on the fifth aspect of this application, in some possible implementations, the third terminal device may also receive fourth instruction information, which is used to instruct the monitoring of the status of the first path or the second path.

[0111] Based on the fifth aspect of this application, in some possible implementations, the third terminal device may also receive a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0112] Based on the fifth aspect of this application, in some possible implementations, the third terminal device may also monitor the status of the first path and / or the second path.

[0113] A sixth aspect of this application provides a communication device, comprising:

[0114] The interface module is used to receive a first request message, which includes the identification information of a first network element, and the first network element is deployed on a first non-terrestrial network device.

[0115] The processing module is used to obtain path status information based on the identification information of the first network element. The path status information is used to indicate the path status between the first network element and the second network element. The second network element is deployed on the second non-terrestrial network device. Both the first network element and the second network element are user plane function network elements.

[0116] Optionally, the interface module is also used to receive path status notification messages, which include the path status between the second network element and multiple network elements.

[0117] The processing module is specifically used to determine the path status information based on the identification information of the first network element and the path status notification message.

[0118] Optionally, the interface module is also used to send a query request message, which includes the identification information of the first network element. The identification information of the first network element is used to obtain the path status between the first network element and the second network element.

[0119] The interface module is also used to receive a first response message, which is a response message to the query request message and is used to indicate path status information.

[0120] Optionally, the interface module is also used to send a second response message, which is a response message to the first request message; wherein, if the path status information indicates that the path status between the first network element and the second network element is available, the second response message includes the tunnel information of the second network element.

[0121] Alternatively, if the path status information indicates that the path status between the first network element and the second network element is unavailable, then the second response message includes a path unavailable indication.

[0122] Optionally, the first request message may also include the tunnel information of the first network element and the Internet Protocol IP address of the first terminal device. The interface module is also used to send a first traffic splitting rule, which instructs the second network element to send the first data packet to the first network element according to the tunnel information of the first network element. The destination address of the first data packet is the IP address of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services to the first terminal device, and the second network element provides services to the second terminal device.

[0123] Optionally, the interface module is specifically used to send the first traffic splitting rule when the path status information indicates that the path status between the first network element and the second network element is available.

[0124] Optionally, the interface module is also used to send a second traffic splitting rule, which instructs the second network element to send the first data packet to the session anchor point. The destination address of the first data packet is the IP address of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services to the first terminal device, and the second network element provides services to the second terminal device. The session anchor point is deployed on the first terrestrial network.

[0125] Optionally, the interface module is specifically used to send a second traffic splitting rule when the path status information indicates that the path status between the first network element and the second network element is unavailable.

[0126] Optionally, the interface module is also used to send first indication information, which instructs the second network element to use the first diversion rule or the second diversion rule according to the path status information.

[0127] Optionally, the interface module is specifically used to send first indication information when sending the first and second traffic splitting rules.

[0128] Optionally, the interface module is also used to receive first information, which is used to indicate that the path status between the first network element and the second network element has changed, or to indicate the switching of the transmission path between the first network element and the second network element.

[0129] The interface module is specifically used to send the first traffic splitting rule based on the first information;

[0130] The interface module is specifically used to send the second routing rule based on the first information.

[0131] Optionally, the interface module is also used to receive second information, which includes service flow information between the second terminal device and the ground access gateway. The ground access gateway is deployed in the second ground network, and the ground access gateway and the second network element transmit data through a session anchor point.

[0132] The interface module is specifically used to respond to the second information by sending the third and fourth traffic splitting rules. The third traffic splitting rule is used to instruct the second network element to send the third data packet to the session anchor point. The third data packet is a data packet sent by the second terminal device to the terrestrial access gateway. The fourth traffic splitting rule is used to instruct the second network element to send the fourth data packet from the session anchor point to the second terminal device. The fourth data packet is a data packet sent by the terrestrial access gateway to the second terminal device.

[0133] Optionally, the interface module is also used to receive third information, which indicates that the path status between the first network element and the second network element has changed;

[0134] If, according to the third information, the path status between the first network element and the second network element changes from unavailable to available, then in response to the third information, a path availability indication is sent.

[0135] Alternatively, if the path status between the first network element and the second network element changes from available to unavailable according to the third information, then in response to the third information, a path unavailable indication is sent.

[0136] Optionally, the first request message also includes the IP address of the second terminal device and the IP address of the terrestrial access gateway. The interface module is also used to send a third traffic splitting rule, which instructs the second network element to send a third data packet from the session anchor to the second terminal device. The third data packet is a data packet sent by the terrestrial access gateway to the second terminal device. The terrestrial access gateway is deployed in the second terrestrial network, and the session anchor is deployed in the first terrestrial network. The terrestrial access gateway and the second network element transmit the third data packet through the session anchor.

[0137] A seventh aspect of this application provides a communication device, comprising:

[0138] The processing module is used to obtain the identification information of the third network element, which is deployed on the first non-terrestrial network device;

[0139] The interface module is used to send the identification information of the third network element. The identification information of the third network element is used to obtain the transmission path between the third terminal device and the fourth terminal device. The third network element provides services to the third terminal device.

[0140] The interface module is also used to receive a third response message, which indicates the transmission path between the third terminal device and the fourth terminal device. The third network element is a user plane function network element or an access gateway.

[0141] Optionally, the interface module is also used to send a third request message, which includes the identification information of the third terminal device;

[0142] The interface module is also used to receive a fourth response message, which is a response message to the third request message and includes the identification information of the third network element.

[0143] Optionally, the third response message includes indication information for the first path and / or indication information for the second path. The first path is the path from the third terminal device to the fourth terminal device via the third network element and the fourth network element. The second path is the path from the third terminal device to the fourth terminal device via a session anchor or a terrestrial access gateway. The fourth network element provides services to the fourth terminal device. The session anchor is deployed in the first terrestrial network, and the terrestrial access gateway is deployed in the second terrestrial network. The session anchor includes a session anchor that provides services to the third terminal device and a session anchor that provides services to the fourth terminal device. The terrestrial access gateway includes a terrestrial access gateway that provides services to the third terminal device and a terrestrial access gateway that provides services to the fourth terminal device.

[0144] Optionally, when the fourth network element is a user plane function network element, the indication information of the first path includes the tunnel information of the fourth network element and the IP address of the fourth terminal device; or, when the fourth network element is an access gateway, the indication information of the first path includes the IP address of the fourth network element; when the second path is a path between the third terminal device and the fourth terminal device through a terrestrial access network element, the indication information of the second path includes the IP address of the terrestrial access gateway; or, when the second path is a path between the third terminal device and the third terminal device through a session anchor point, the indication information of the second path includes the IP address of the fourth terminal device.

[0145] Optionally, the interface module is also used to send call signaling, which is used to indicate the first path and / or the second path.

[0146] The call signaling includes any one of the following: the IP address of the fourth terminal device, the IP address of the terrestrial access gateway, wherein the terrestrial access gateway is the terrestrial access gateway that provides services to the third terminal device, and the IP address of the third network element.

[0147] Scenario A: When the third response message indicates the first path and the third network element is a user plane function network element, the call signaling includes the IP address of the fourth terminal device. In this case, the third terminal device directly sends the session data packet to the fourth terminal device using the fourth terminal device's IP address.

[0148] Scenario B: When the fourth response message indicates the first path and the third network element is an access gateway, the call signaling includes the IP address of the third network element. In this case, the third terminal device first sends the session data packet destined for the fourth terminal device to the third network element, and then the third network element sends the session data packet to the fourth terminal device.

[0149] Scenario C: When the fourth response message indicates the second path, and the second path is the path between the third terminal device and the fourth terminal device through the session anchor, the call signaling includes the IP address of the fourth terminal device. In this case, the third terminal device sends session data packets directly to the fourth terminal device using the fourth terminal device's IP address.

[0150] Scenario D: When the fourth response message indicates the second path, and the second path is the path between the third terminal device and the fourth terminal device via a terrestrial access gateway, the call signaling includes the IP address of the terrestrial access gateway, which is the terrestrial access gateway providing services to the third terminal device. In this case, the third terminal device first sends the session data packets intended for the fourth terminal device to the terrestrial access gateway serving the third terminal device, and then the terrestrial access gateway forwards the session data packets to the fourth terminal device.

[0151] When the fourth response message simultaneously indicates the first path and the second path, the call signaling includes the information included in situation A or situation B and the information corresponding to situation C or situation D, respectively.

[0152] Optionally, the interface module is also used to receive third information, which indicates that the path status of the first path or the second path has changed.

[0153] The interface module is also used to send a fourth message, which indicates whether to switch the first path to the second path or to indicate whether to switch the second path to the first path.

[0154] Optionally, when the fourth information is used to indicate switching the first path to the second path, and the second path is the path between the third terminal device and the fourth terminal device through the terrestrial access gateway, the fourth information includes the IP address of the terrestrial access gateway, which is a terrestrial access gateway that provides services to the third terminal device and is deployed in the second terrestrial network.

[0155] Alternatively, when the fourth information is used to indicate switching the first path to the second path, and the second path is the path between the third terminal device and the fourth terminal device through the session anchor, the fourth information includes the IP address of the third terminal device.

[0156] Alternatively, when the fourth information indicates that the second path is switched to the first path and the third network element is a user plane function network element, the fourth information includes the tunnel information of the third network element and the IP address of the third terminal device, and the third network element provides services to the third terminal device.

[0157] Alternatively, when the fourth information indicates that the second path should be switched to the first path and both the third and fourth network elements are access gateways, the fourth information includes the IP address of the third network element.

[0158] Optionally, the interface module is also used to send second indication information, which includes address information required by the third terminal device to send session data to the fourth terminal device through a target path, wherein the target path is either the first path or the second path.

[0159] In the case where the target path is as described in scenario A above, the second instruction information is used to instruct the third terminal device to send the session data packet directly to the fourth terminal device through the IP address of the fourth terminal device.

[0160] When the target path is case B above, the second instruction information is used to instruct the third terminal device to send the session data packet destined for the fourth terminal device to the third network element first, and then the third network element sends the session data packet to the fourth terminal device.

[0161] When the target path is case C as described above, the second instruction information is used to instruct the third terminal device to send the session data packet directly to the fourth terminal device through the IP address of the fourth terminal device.

[0162] When the target path is case D as described above, the second indication information is used to instruct the third terminal device to first send the session data packets destined for the fourth terminal device to the ground access gateway serving the third terminal device, and then the ground access gateway will send the session data packets to the fourth terminal device.

[0163] Optionally, the interface module is also used to send a fifth message during the path switching process. The fifth message includes service flow information between the third terminal device and the ground access gateway.

[0164] Optionally, the call signaling may also include third indication information, which is used to instruct the third terminal device to transmit data using the first path or the second path according to the path status of the first path and / or the second path.

[0165] Optionally, the call signaling may also include a path selection policy, which may include one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0166] Optionally, the call signaling may also include fourth indication information, which is used to instruct the third terminal device to perform path monitoring to obtain the path status of the first path and / or the second path.

[0167] Optionally, the third network element is an access gateway, and the third response message includes information about the third path and / or the fourth path. The information about the third path includes the IP address of the fourth network element. The fourth network element is deployed on the second non-terrestrial network device. The fourth network element is an access gateway that provides services to the fourth terminal device. The information about the fourth path includes the IP address of the terrestrial access gateway. The terrestrial access gateway is deployed on the second terrestrial network. The third path is the path from the third terminal device to the fourth terminal device through the third network element and the fourth network element. The fourth path is the path from the third terminal device to the fourth terminal device through the third network element and the terrestrial access gateway.

[0168] Optionally, the interface module is also used to send a fifth indication message, which instructs the third network element to use the third path or the fourth path to transmit data according to the path status of the third path and / or the fourth path.

[0169] Optionally, the interface module is also used to send a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0170] The interface module is also used to send a sixth indication message, which is used to instruct the third network element to monitor the path status of the third path and / or the fourth path.

[0171] Optionally, when both the third network element and the fourth network element are access gateways, the third response message includes path status information. The processing module is also used to determine the transmission path based on the path status information. The path status information is determined based on the identification information of the third network element. The path status information is used to indicate the path status between the third network element and the fourth network element. The fourth network element provides services to the fourth terminal device.

[0172] The eighth aspect of this application provides a communication device, comprising:

[0173] The interface module is used to receive the identification information of the third network element. The identification information of the third network element is used to obtain the transmission path between the third terminal device and the fourth terminal device. The third network element provides services to the third terminal device. The third network element is a user plane function network element or an access gateway. The third network element is deployed on the first non-terrestrial network device.

[0174] The processing module is used to generate the third response message;

[0175] The interface module is also used to send a third response message, which indicates the transmission path between the third terminal device and the fourth terminal device.

[0176] Optionally, the interface module is also used to send a second request message, which includes the identification information of the third network device;

[0177] The interface module is also used to receive a fourth response message, which is a response message to the second request message. The fourth response message is used to indicate the path establishment status between the third network element and the fourth network element. The fourth network element provides services to the fourth terminal device. The fourth network element is deployed on the second non-terrestrial network device.

[0178] The processing module is also used to determine the transmission path between the third terminal device and the fourth terminal device based on the path establishment status between the third network element and the network element.

[0179] Optionally, the third response message includes indication information for the first path or indication information for the second path. The first path is the path from the third terminal device to the fourth terminal device through the third network element and the fourth network element. The second path is the path from the third terminal device to the fourth terminal device through the session anchor point or the terrestrial access gateway. The fourth network element provides services to the fourth terminal device. The session anchor point is deployed in the first terrestrial network, and the terrestrial access gateway is deployed in the second terrestrial network.

[0180] Optionally, if the path establishment status between the third network element and the fourth network element is successful, the third response message includes indication information of the first path;

[0181] Alternatively, if the path establishment status between the third network element and the fourth network element is in the establishment failure status, the second response message includes indication information of the second path.

[0182] Optionally, when the third network element is a user plane function network element, the indication information of the first path includes the tunnel information of the third network element and the IP address of the third terminal device; or, when the third network element is an access gateway, the indication information of the first path includes the IP address of the third network element; the indication information of the second path includes the IP address of the terrestrial access gateway.

[0183] Optionally, the interface module is also used to send call signaling, which includes the IP address of the third terminal device and / or the IP address of the terrestrial access gateway; or, when the fourth network element is an access gateway, the call signaling includes the IP address of the fourth network element and / or the IP address of the terrestrial access gateway.

[0184] Optionally, the interface module is also used to receive third information, which indicates that the path status of the first path or the second path has changed.

[0185] The interface module is also used to send a fourth message, which indicates whether to switch the first path to the second path or to indicate whether to switch the second path to the first path.

[0186] Optionally, when the fourth information is used to indicate switching the first path to the second path, the fourth information includes the IP address of the ground access gateway, which is deployed in the second ground network;

[0187] Alternatively, when the fourth information indicates that the second path is switched to the first path and both the third and fourth network elements are user plane function network elements, the fourth information includes the tunnel information of the third network element and the IP address of the third terminal device, and the third network element provides services to the third terminal device.

[0188] Alternatively, when the fourth information indicates that the second path should be switched to the first path and both the third and fourth network elements are access gateways, the fourth information includes the IP address of the fourth network element.

[0189] Optionally, the interface module is also used to send a second indication message, which is used to instruct the fourth terminal device to switch the first path to the second path or to switch the second path to the first path.

[0190] Optionally, the interface module is also used to send a fifth piece of information, which includes service flow information between the fourth terminal device and the ground access gateway.

[0191] Optionally, the call signaling may also include third indication information, which is used to instruct the fourth terminal device to transmit data using the first path or the second path according to the path status of the first path and / or the second path.

[0192] Optionally, the call signaling may also include a path selection policy, which may include one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0193] Optionally, the call signaling may also include fourth indication information, which is used to instruct the fourth terminal device to perform path monitoring to obtain the path status of the first path and / or the second path.

[0194] Optionally, the fourth network element is an access gateway, and the third response message includes information about the third path and / or the fourth path. The information about the third path includes the IP address of the third network element. The third network element is deployed on the second non-terrestrial network device. The third network element is an access gateway. The information about the fourth path includes the IP address of the terrestrial access gateway. The terrestrial access gateway is deployed on the second terrestrial network. The third path is the path between the third network element and the fourth network element, and the fourth path is the path between the fourth network element and the terrestrial access gateway.

[0195] Optionally, the interface module is also used to send a fifth indication message, which instructs the fourth network element to use the third path or the fourth path to transmit data based on the path status of the third path and / or the fourth path.

[0196] Optionally, the interface module is also used to send a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0197] The interface module is also used to send a sixth indication message, which is used to instruct the fourth network element to monitor the path status of the third path and / or the fourth path.

[0198] Optionally, the processing module is also used to determine the transmission path based on the path status information. The path status information is determined based on the identification information of the third network element. The path status information is used to indicate the path status between the third network element and the fourth network element, and the fourth network element provides services to the fourth terminal device.

[0199] The ninth aspect of this application provides a communication device, comprising:

[0200] The processing module is used to determine path status information, which is used to indicate the path status between the third network element and the fourth network element. The third network element is deployed on the first non-terrestrial network device, and the fourth network element is deployed on the second non-terrestrial network device. Both the third network element and the fourth network element are user plane function network elements, or both the third network element and the fourth network element are access gateways.

[0201] The interface module is used to transmit path status information;

[0202] The processing module is also used to determine the transmission path between the third terminal device and the fourth terminal device based on the path status information. The first network element provides services to the first terminal device, and the second network element provides services to the second terminal device.

[0203] Optionally, the transmission path includes: a first path and / or a second path, wherein the first path is the path between the third terminal device and the fourth terminal device through the third network element and the fourth network element, and the second path is the path between the third terminal device and the fourth terminal device through a session anchor point or a terrestrial access gateway, wherein the session anchor point is deployed in the first terrestrial network, or the terrestrial access gateway is deployed in the second terrestrial network.

[0204] Optionally, when the second path is a path between the third terminal device and the fourth terminal device through a session anchor point, the interface module is also used to receive a first traffic splitting rule and / or a second traffic splitting rule, wherein the first traffic splitting rule is used to indicate the first path and the second traffic splitting rule is used to indicate the second path.

[0205] Optionally, the interface module is also used to receive first indication information, which is used to indicate whether to use a first diversion rule or a second diversion rule based on the path status information.

[0206] The processing module is also configured to, in response to the first indication information, determine the transmission path of the first data packet using the first diversion rule or the second diversion rule based on the path status information.

[0207] Optionally, the processing module is specifically used to determine the transmission path as the first path if the path status of the first path is available.

[0208] Alternatively, if the path status of the first path is unavailable, then the transmission path is determined to be the second path.

[0209] Optionally, when the third network element and the fourth network element are access gateways, the transmission path includes: a third path and / or a fourth path, where the third path is the path between the third network element and the fourth network element, and the fourth path is the path between the third network element and the fourth network element through the ground access gateway, where the ground access gateway is deployed in the second ground network.

[0210] Optionally, when the second path is the path between the third terminal device and the fourth terminal device through the terrestrial access gateway, the interface module is also used to receive a path configuration message. The path configuration message includes the IP address of the third network element and / or the IP address of the terrestrial access gateway. The IP address of the third network element is used to indicate the first path or the third path, and the IP address of the terrestrial access gateway is used to indicate the second path or the fourth path.

[0211] Optionally, the interface module is also used to receive fifth indication information, which instructs the third network element to use the third path or the fourth path to transmit data according to the path status of the third path and / or the fourth path.

[0212] Optionally, the interface module is also used to receive path selection strategies, which include one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0213] Optionally, the interface module is specifically used to receive path status subscription requests. The path status subscription request is used to request that when the path status between the fourth network element and any one of the at least one network element changes, a path status notification message is sent.

[0214] The interface module is specifically used to send path status notification messages, which indicate the path status between the fourth network element and any network device in at least one network element. The path status notification message includes path status information.

[0215] Optionally, the interface module is also used to receive query request messages, which include the identification information of the third network element and are used to request the query of the path status between the third network element and the fourth network element.

[0216] The interface module is also used to send a first response message, which is a response message to the query request message and is used to indicate path status information.

[0217] Optionally, the interface module is also used to send first information, which indicates that the path status between the first network element and the second network element has changed.

[0218] The tenth aspect of this application provides a communication device, comprising:

[0219] The interface module is used to receive indication information of the first path and indication information of the second path. The first path is used to send the second data packet to the fourth terminal device, and the second path is used to send the second data packet to the ground access gateway. The second data packet is a data packet sent by the third terminal device to the fourth terminal device.

[0220] The processing module is used to determine the transmission path of the second data packet based on the indication information of the first path and the indication information of the second path.

[0221] Optionally, the indication information for the first path includes the IP address of the third network element, and the indication information for the second path includes the IP address of the terrestrial access gateway. The third network element provides services to the third terminal device.

[0222] Optionally, the interface module is also used to receive third indication information, which is used to indicate the path of the second data packet determined according to the status of the first path or the second path.

[0223] Optionally, the interface module is also used to receive a fourth indication information, which is used to indicate the monitoring of the status of the first path or the second path.

[0224] Optionally, the interface module is also used to receive path selection strategies, which include one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0225] Optionally, the processing module is also used to monitor the status of the first path and / or the second path.

[0226] The eleventh aspect of this application provides a communication device, which may be the aforementioned SMF network element, first P-CSCF, second P-CSCF, fourth network element, or third terminal device; it may also be a component (e.g., processor, chip, or chip system) applied to the aforementioned SMF network element, first P-CSCF, second P-CSCF, fourth network element, or third terminal device; or it may be a logic module or software capable of implementing all or part of the functions of the aforementioned SMF network element, first P-CSCF, second P-CSCF, fourth network element, or third terminal device. The communication device includes:

[0227] A processor for executing a program that causes the communication device to perform the method as described in any one of the first to fifth aspects and any possible implementation thereof.

[0228] Optionally, the communication device further includes a memory, and the processor is coupled to the memory; the memory is used to store programs.

[0229] The twelfth aspect of this application provides a chip or chip system including at least one processor and a communication interface, the communication interface and at least one processor being interconnected via a line, the at least one processor being used to run computer programs or instructions to perform the communication method described in any of any possible implementations of any of the first to fifth aspects.

[0230] The communication interface in the chip can be an input / output interface, pins, or circuits.

[0231] In one possible implementation, the chip or chip system described above in this application further includes at least one memory storing instructions. The memory can be an internal storage unit of the chip, such as a register or cache, or it can be a storage unit of the chip itself, such as a read-only memory or random access memory.

[0232] The thirteenth aspect of this application provides a communication system, including communication means for performing any one of the first to fifth aspects and any possible implementation thereof.

[0233] The fourteenth aspect of this application provides a computer-readable storage medium including instructions that, when executed on a computer, cause the computer to perform the method described in the first aspect above, or cause the computer to perform the method described in the second aspect above, or cause the computer to perform the method described in the third aspect above, or cause the computer to perform the method described in the fourth aspect above, or cause the computer to perform the method described in the fifth aspect above.

[0234] The fifteenth aspect of this application provides a computer program product containing instructions that, when run on a computer, cause the computer to perform the method described in the first aspect above, or cause the computer to perform the method described in the second aspect above, or cause the computer to perform the method described in the third aspect above, or cause the computer to perform the method described in the fourth aspect above, or cause the computer to perform the method described in the fifth aspect above. Attached Figure Description

[0235] Figure 1 is a diagram of the ground network architecture in an embodiment of this application;

[0236] Figure 2 is a diagram of the non-terrestrial network architecture in an embodiment of this application;

[0237] Figure 3 illustrates a possible application scenario of the communication method in the embodiments of this application;

[0238] Figure 4 shows another possible application scenario of the communication method in the embodiments of this application;

[0239] Figure 5 is a schematic diagram of an embodiment of the communication method in this application;

[0240] Figure 6 is a schematic diagram of another embodiment of the communication method in this application;

[0241] Figure 7 is a schematic diagram of another embodiment of the communication method in this application;

[0242] Figure 8 is a schematic diagram of another embodiment of the communication method in this application;

[0243] Figure 9 is a schematic diagram of another embodiment of the communication method in this application;

[0244] Figure 10 is a schematic diagram of another embodiment of the communication method in this application;

[0245] Figure 11 is a schematic diagram of another embodiment of the communication method in this application;

[0246] Figure 12 is a schematic diagram of an embodiment of the communication device in this application;

[0247] Figure 13 is a schematic diagram of another embodiment of the communication device in this application;

[0248] Figure 14 is a schematic diagram of another embodiment of the communication device in this application;

[0249] Figure 15 is a schematic diagram of another embodiment of the communication device in this application;

[0250] Figure 16 is a schematic diagram of another embodiment of the communication device in this application;

[0251] Figure 17 is a schematic diagram of another embodiment of the communication device in this application;

[0252] Figure 18 is a schematic diagram of another embodiment of the communication device in this application. Detailed Implementation

[0253] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0254] References to "one embodiment" or "some embodiments" as described in this application mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0255] In the description of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. "And / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, "at least one" means one or more, and "multiple" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can represent: a, b, c; a and b; a and c; b and c; or a and b and c. Where a, b, and c can be single or multiple.

[0256] It is understood that in this application, "instruction" can include direct instruction, indirect instruction, explicit instruction, and implicit instruction. When describing a certain instruction information to indicate A, it can be understood that the instruction information carries A, directly indicates A, or indirectly indicates A.

[0257] The terms "first," "second," etc., used in the specification, claims, and drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the description of embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to those processes, methods, products, or apparatuses.

[0258] In the embodiments of this application, "When..., execute step A" and "If..., then execute step A" can both mean that step A is executed when a certain condition is met, rather than limiting the timing of step A. "When..., B includes C" and "If..., then B includes C" can both mean that the content of B includes / carries C when a certain condition is met.

[0259] First, some technical terms involved in the embodiments of this application will be introduced.

[0260] 1) Proxy-call session control function (P-CSCF) network element:

[0261] The P-CSCF (Personal Communication Center for Transaction Processing) element is a key functional entity within the Internet Protocol (IP) Multimedia Subsystem (IMS). It serves as the unified entry point for IMS access to the network; all session control messages originating from and terminating at IMS terminals pass through the P-CSCF. It functions similarly to a proxy server, receiving service requests and relaying them within the IMS subnet. In addition, the P-CSCF handles various functions including user authentication, signaling compression, roaming control, and Quality of Service (QoS) policy adjudication. When a terminal device needs to establish a session with another, it sends a Session Initiation Protocol (SIP) request (SIP Invite) to the P-CSCF. The P-CSCF receives the SIP Invite request and, based on its content and destination address, forwards it to the appropriate IMS element for processing.

[0262] 2) Session Management Function (SMF) network element:

[0263] Session Management Function (SMF) is a functional unit in the service-based architecture (SBA) of 5G (5th generation mobile communication technology), primarily responsible for session management. As an important component of the 5G core network (5GC), it works closely with other network elements in the user plane function (UPF) and control plane functions to provide users with high-quality communication services. One of the SMF's functions is to maintain the data transmission tunnel between the terminal equipment and the UPF, ensuring the correct routing and transmission of data packets.

[0264] 3) Access Gateway (AGW):

[0265] AGW, or IMS AGW, is a network element in IMS that acts as a media gateway, transmitting media data packets between different terminal devices.

[0266] Here are some of the key features and functionalities of AGW:

[0267] Media Conversion: AGW can convert media streams so that non-IMS devices can use the services provided by the IMS network.

[0268] Signaling conversion: AGW is responsible for converting traditional signaling protocols (such as ISUP, SS7) into signaling protocols used by IMS (such as SIP).

[0269] Access control: AGW can perform access control to ensure that only authorized users and devices can access the IMS network.

[0270] Bearer control: AGW manages the establishment and maintenance of the bearer layer, including QoS (Quality of Service) management and bandwidth allocation.

[0271] Transcoding function: AGW can transcode voice or video to adapt to the requirements of different devices and networks.

[0272] Security: AGW supports encryption and authentication mechanisms to ensure secure communication.

[0273] Interoperability: AGW supports interoperability with a variety of non-IMS networks, including fixed-line and mobile phone networks.

[0274] Service continuity: AGW supports maintaining service continuity when users move or network conditions change.

[0275] Location services: AGW can support location services provided by the IMS network.

[0276] Billing and Recharge: AGW can interact with the billing system to provide billing and recharge services for non-IMS devices.

[0277] 4) Inter-satellite link (ISL):

[0278] Inter-satellite links, also known as interplanetary links or crosslinks, are links used for communication between satellites. These links allow satellites to directly transmit data and signals without the need for relays through terrestrial network equipment, thereby improving data transmission efficiency and speed, and reducing communication latency. Depending on the orbital type of the satellites at both ends, inter-satellite links can be divided into inter-satellite links between satellites of the same orbital type and inter-satellite links between satellites of different orbital types. Inter-satellite links between satellites of the same orbital type include links between geostationary earth orbit (GEO) satellites and links between low earth orbit (LEO) satellites. Inter-satellite links between satellites of different orbital types include links between GEO and LEO satellites, and links between LEO and medium earth orbit (MEO) satellites.

[0279] Please refer to Figure 1. The following is a brief description of the terrestrial network architecture on which the communication method in this embodiment is based:

[0280] Figure 1 is a possible, non-limiting system schematic diagram. As shown in Figure 1, the communication system 10 includes a radio access network (RAN) 100, a core network (CN) 200, and an Internet 300. RAN 100 includes at least one RAN node (110a and 110b in Figure 1, collectively referred to as 110) and at least one terminal (120a-120j in Figure 1, collectively referred to as 120). RAN 100 may also include other RAN nodes, such as wireless relay equipment and / or wireless backhaul equipment (not shown in Figure 1). Terminal 120 is wirelessly connected to RAN node 110. RAN node 110 is wirelessly or wired connected to core network 200. The core network equipment in core network 200 and RAN node 110 in RAN 100 can be different physical devices, or they can be the same physical device integrating core network logical functions and radio access network logical functions.

[0281] RAN 100 can be a cellular system related to the 3rd Generation Partnership Project (3GPP), such as a 4G, 5G, or future mobile communication system. RAN 100 can also be an open-radio access network (ORAN), a cloud-radio access network (CRAN), or a wireless fidelity (WiFi) system. RAN 100 can also be a communication system that integrates two or more of the above systems.

[0282] RAN node 110, sometimes also referred to as access network equipment, RAN entity, or access node, constitutes part of the communication system and is used to help terminals achieve wireless access. Multiple RAN nodes 110 in communication system 10 can be of the same type or different types. In some scenarios, the roles of RAN node 110 and terminal 120 are relative. For example, network element 120i in Figure 1 can be a helicopter or drone, which can be configured as a mobile base station. For terminals 120j accessing RAN 100 through network element 120i, network element 120i is a base station; but for base station 110a, network element 120i is a terminal. RAN node 110 and terminal 120 are sometimes both referred to as communication devices. For example, network elements 110a and 110b in Figure 1 can be understood as communication devices with base station functions, and network elements 120a-120j can be understood as communication devices with terminal functions.

[0283] In one possible scenario, access network equipment includes, but is not limited to: evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved Node B, or home Node B, HNB), baseband unit (BBU), access point (AP) in wireless fidelity (WIFI) system, macro base station, micro base station, wireless relay node, donor node, radio controller in CRAN scenario, wireless backhaul node, transmission point (TP), or transmission and reception point (TRP), etc., and can also be access network equipment in 5G mobile communication system. For example, a next-generation NodeB (gNB), TRP, or TP in an NR system; or one or a group of antenna panels (including multiple antenna panels) in a base station in a 5G mobile communication system; or, access network equipment can also be network nodes constituting a gNB or transmission point. Examples include centralized units (CU), distributed units (DU), centralized unit control planes (CU-CP), centralized unit user planes (CU-UP), or radio units (RU), etc. CUs and DUs can be separate or included in the same network element, such as a BBU. RUs can be included in radio equipment or radio units, such as in a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). Alternatively, access network equipment can also be servers, wearable devices, vehicles, or in-vehicle equipment, etc. For example, the access network equipment in V2X technology can be a roadside unit (RSU). It should be understood that the aforementioned TRP can be a device or module located on the network side of the aforementioned communication system and having corresponding communication functions.The TRP typically contains communication modules, circuits, or chips that perform the corresponding communication functions. The TRP can also be configured with program instructions for the corresponding communication functions.

[0284] It should be noted that CU (or CU-CP and CU-UP), DU, or RU may have different names in different systems, but those skilled in the art will understand their meaning. For example, in an open radio access network (ORAN) system, CU can also be called an open centralized unit (O-CU) or an open CU, DU can also be called an open distributed unit (O-DU), CU-CP can also be called an open centralized unit control plane (O-CU-CP), CU-UP can also be called an open centralized unit user plane (O-CU-UP), and RU can also be called an open radio unit (O-RU). This application does not limit the specific names. Any of the units CU, CU-CP, CU-UP, DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0285] Optionally, for network elements in the ORAN system, each network element can implement the protocol layer functions shown in Table 1 below.

[0286] Table 1

[0287] It should be noted that in the ORAN system, the access network equipment in this application can be one or more network elements listed in Table 1 above.

[0288] The architecture of the CU and DU of the access network equipment is described below. An access network equipment includes at least one CU and at least one DU. Optionally, the access network equipment may also include at least one RU.

[0289] The following description uses an access network device consisting of one CU and one DU as an example. The CU has some core network functions and can include CU-CP and CU-UP. The CU and DU can be configured according to the protocol layer functions of the wireless network they implement. For example, the CU may be configured to implement the functions of the Packet Data Convergence Protocol (PDCP) layer and above (e.g., RRC and / or SDAP layers). The DU may be configured to implement the functions of protocol layers below the PDCP layer (e.g., RLC, MAC, and / or physical (PHY) layers). Alternatively, the CU may be configured to implement the functions of protocol layers above the PDCP layer (e.g., RRC and / or SDAP layers), and the DU may be configured to implement the functions of protocol layers below the PDCP layer (e.g., RLC, MAC, and / or PHY layers).

[0290] When a CU includes CU-CP and CU-UP, CU-CP is used to implement the control plane functions of the CU, and CU-UP is used to implement the user plane functions of the CU. For example, when a CU is configured to implement the functions of the PDCP layer, RRC layer, and SDAP layer, CU-CP is used to implement the RRC layer functions and the control plane functions of the PDCP layer, and CU-UP is used to implement the SDAP layer functions and the user plane functions of the PDCP layer.

[0291] The CU-CP can interact with network elements in the core network used to implement control plane functions. These network elements can be access and mobility function (AMF) network elements, such as the AMF in a 5G system. The AMF is responsible for mobility management in the mobile network, such as terminal device location updates, terminal device registration with the network, and terminal device handover.

[0292] CU-UP can interact with network elements in the core network used to implement user plane functions. These network elements, such as the user plane function (UPF) in a 5G system, are responsible for forwarding and receiving data in terminal devices.

[0293] The above CU and DU configurations are merely examples; the functions of the CU and DU can be configured as needed. For instance, the CU or DU can be configured to have more protocol layer functions, or only some protocol layer processing functions. For example, some RLC layer functions and protocol layer functions above the RLC layer can be placed in the CU, while the remaining RLC layer functions and protocol layer functions below the RLC layer can be placed in the DU. Furthermore, the functions of the CU or DU can be divided according to service type or other system requirements. For example, based on latency, functions that require low latency can be placed in the DU, while functions that do not require low latency can be placed in the CU.

[0294] DU and RU can cooperate to implement the functions of the PHY layer. A DU can be connected to one or more RUs. The functions of DU and RU can be configured in various ways depending on the design. For example, a DU can be configured to implement baseband functions, and an RU can be configured to implement mid-RF functions. Another example is that a DU can be configured to implement higher-level functions in the PHY layer, and an RU can be configured to implement lower-level functions in the PHY layer, or to implement both lower-level and RF functions. Higher-level functions in the physical layer can include a portion of the physical layer's functions that are closer to the MAC layer, while lower-level functions in the physical layer can include another portion of the physical layer's functions that are closer to the mid-RF side.

[0295] It should be noted that the access network equipment can be a device or apparatus with a chip, or a device or apparatus with integrated circuits, or a chip, chip system, module, or control unit in the aforementioned device or apparatus; this application does not impose any specific limitation. It should also be noted that in this application, the term "access network equipment" can refer to the access network equipment itself, or to the chip, functional module, or integrated circuit within the access network equipment that performs the method provided in this application; this application does not impose any specific limitation.

[0296] In another possible scenario, multiple RAN nodes collaborate to assist the terminal in achieving wireless access, with each RAN node performing a portion of the base station's functions. For example, RAN nodes can be central units (CUs), distributed units (DUs), CU-CPs, CU-UPs, or radio units (RUs). CUs and DUs can be configured separately or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio equipment or radio units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs).

[0297] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0298] A terminal can be a device or module that accesses the aforementioned communication system and has corresponding communication functions. A terminal can also be called a terminal device, user equipment (UE), mobile station, mobile terminal, etc. Terminals can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart homes, smart offices, smart wearables, intelligent transportation, smart cities, etc. Terminals can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, transportation vehicles with wireless communication capabilities, communication modules, etc. The embodiments of this application do not limit the device form of the terminal. Terminals typically contain communication modules, circuits, or chips that perform corresponding communication functions. Terminals can also be configured with program instructions for performing corresponding communication functions.

[0299] In this embodiment, RAN nodes can be deployed on satellites. For example, base stations can be deployed entirely on satellites. Core network equipment can also be deployed on satellites; for example, core network user plane elements can be deployed on satellites to support direct communication between terminals via satellite, eliminating the need for terrestrial communication. Some core network control plane elements can also be deployed on satellites. For example, deploying mobility management and session management elements on satellites can support emergency rescue services in disaster scenarios where no terrestrial network is available. Furthermore, IMS AGWs can also be deployed on satellites. When communication between terminals is directly exchanged via satellite, deploying IMS AGWs on satellites can support functions such as call billing.

[0300] Please refer to Figure 2. The following is a brief description of the non-terrestrial network (NTN) architecture on which the communication method in this embodiment is based:

[0301] Ground mobile terminals access the network via a new air interface. Network equipment is deployed on satellites and connected to the ground core network via wireless links. Simultaneously, inter-satellite links can exist between satellites to facilitate signaling interaction and user data transmission between network devices. The various network elements in Figure 2 and their interfaces are described below:

[0302] Terminal: Mobile devices that support the New Radio interface, typically such as mobile phones and tablets. They can access satellite networks via the air interface and initiate services such as making calls and accessing the internet.

[0303] Network equipment primarily provides wireless access services, allocates wireless resources to access terminals, and provides reliable wireless transmission protocols and data encryption protocols. In addition to wireless base stations, network equipment deployed on satellites also includes user plane network element functions and IMS AGW functions. This satellite-deployed network equipment is referred to as NTN nodes.

[0304] Core Network: Handles user access control, mobility management, session management, user security authentication, billing, and other services. It consists of multiple functional units, which can be divided into control plane and data plane functional entities. The Access and Mobility Management Unit (AMF) is responsible for user access management, security authentication, and mobility management. The User Plane Unit (UPF) is responsible for managing user plane data transmission, traffic statistics, and other functions. User plane network elements can be deployed on satellites or on the ground. In the embodiments of this application, the anchor user plane network element is deployed on the ground. The anchor user plane network element is the anchor point for the IP address of the terminal device. In the 5G system, the anchor user plane network element is a protocol data unit session anchor (PSA), responsible for the allocation of IP addresses for the terminal device.

[0305] Ground station: Responsible for forwarding signaling and service data between satellite base stations and the core network. A ground station is a network device deployed on the ground. It can be a network device, a component of a network device (such as a processor, chip, or chip system), or a logical module or software that implements all or part of the functions of the network device.

[0306] New Radio: The wireless link between a terminal and a base station.

[0307] Xn interface: The interface between base stations, mainly used for signaling interaction such as handover.

[0308] NG interface: The interface between the base station and the CN, mainly used for exchanging non-access stratum (NAS) signaling of the core network and user service data.

[0309] The terminal device in Figure 2 can be located within the beam or cell coverage area of ​​the network device. The terminal device can communicate with the network device over the air via uplink (UL) or downlink (DL). For example, in the UL direction, the terminal device can send uplink data to the network device via the physical uplink shared channel (PUSCH); in the DL direction, the network device can send downlink data to the terminal device via the physical downlink shared channel (PDSCH). The terminal device can be a terminal device supporting New Radio (NR), which can access the network device over the air and initiate services such as calls and internet access. For example, the network device can be a RAN device (or RAN payload) mounted on an NTN device (e.g., a satellite). When the RAN device is mounted on the NTN device, the RAN device moves synchronously with the NTN device. Furthermore, the communication link between the RAN device mounted on the NTN device and the terminal device can be called a service link. When the communication system includes multiple RAN devices, the RAN devices mounted on the NTN device can communicate with each other via the Xn interface. In practical applications, network devices can also be RAN devices distributed on NTN devices based on DUs; specific details are not limited here. The terminal devices and network devices shown in Figure 2 can be referenced from the descriptions of terminal devices and network devices in Figure 1, which will not be repeated here.

[0310] The aforementioned NTN device can be a satellite, drone, or other aircraft. For example, an NTN device may include a geostationary earth orbit (GEO) satellite, a non-geostationary orbit satellite, a low-earth orbit (LEO) satellite, a medium-earth orbit (MEO) satellite, a geosynchronous orbit satellite, an unmanned aerial vehicle system platform, a high altitude platform station (HAPS), a hot air balloon, or a high-orbit satellite, etc., and is not specifically limited here. This application uses a satellite as the NTN device for illustration.

[0311] Low-Earth orbit (LEO) and medium-Earth orbit (MEO) satellites can have their own orbital paths, and multiple satellites typically work together to provide communication over a fixed area. High-Earth orbit (GEO) satellites are generally stationary, and one or a few high-Earth orbit satellites provide communication over a fixed area.

[0312] Furthermore, the embodiments of this application can also be applied to other future communication technologies. The network architecture and service scenarios described in this application are for the purpose of more clearly illustrating the technical solutions of this application, and do not constitute a limitation on the technical solutions provided in this application. As those skilled in the art will understand, with the evolution of network architecture and the emergence of new service scenarios, the technical solutions provided in this application are also applicable to similar technical problems.

[0313] Figure 3 illustrates a possible application scenario of an embodiment of this application. The UPF network element is deployed on an NTN device, for example, on a satellite. Exemplarily, the satellite accessed by UE1 is denoted as the first satellite, and the satellite accessed by UE2 is denoted as the second satellite. The inter-satellite link between the first and second satellites is ISL1. UE1 communicates with UE2 through the onboard UPF1 deployed on the first satellite, the ISL1 between the first and second satellites, and the onboard UPF2 deployed on the second satellite. The onboard UPF1 sends data packets from UE1 to the onboard UPF2 via ISL1, and the onboard UPF2 then forwards the data packets to UE2.

[0314] Figure 4 illustrates another possible application scenario of this embodiment. In this scenario, both the UPF network element and the AGW are deployed on NTN equipment, for example, on a satellite. Exemplarily, the satellite accessed by UE1 is denoted as the first satellite, and the satellite accessed by UE2 is denoted as the second satellite. The inter-satellite link between the first and second satellites is ISL1. UE1 communicates with UE2 through the onboard AGW1 deployed on the first satellite, the ISL1 between the first and second satellites, and the onboard AGW2 deployed on the second satellite. The onboard AGW1 sends data packets from UE1 to the onboard AGW2 via ISL1, and the onboard AGW2 then forwards the data packets to UE2. In this application scenario, the UPF1 deployed on the first satellite and the UPF2 deployed on the second satellite are responsible for the local offloading of communication data packets between UE1 and UE2, that is, offloading uplink data packets to AGW1 and AGW2.

[0315] In the scenarios shown in Figures 3 and 4, the core network control plane elements, such as AMF and SMF, and the IMS control plane elements, such as P-CSCF and S-CSCF, are all assumed to be deployed on the ground in the description of the subsequent embodiments. However, this application does not limit the deployment location of the core network control plane elements and the IMS control plane elements.

[0316] In the scenarios shown in Figures 3 and 4 above, UE1 is referred to as the calling UE, and UE2 as the called UE. This communication method is called UE-SAT-UE communication, meaning that UEs exchange data via inter-satellite links, and data packets are exchanged without passing through ground equipment. When initiating a session, the P-CSCF network element and / or SMF network element need to determine whether to enable UE-SAT-UE communication based on whether the calling and called UEs access the satellite. In practical applications, inter-satellite links between satellites may not necessarily exist. For example, there may be opposing orbits in the satellite network. Satellites in opposing orbits may be spatially close for a period of time, but their directions of motion are opposite. Due to the high relative speed, it is difficult to establish inter-satellite links between satellites in opposing orbits. Therefore, the P-CSCF network element and / or SMF network element need to first obtain the status of the inter-satellite link between the first and second satellites to determine whether the first and second satellites support UE-SAT-UE communication. Currently, the P-CSCF network element and / or SMF network element need to query external systems, such as the satellite routing subsystem, to obtain information on whether direct inter-satellite link communication is supported between the two satellites.

[0317] However, the interfaces between P-CSCF or SMF network elements and external systems are difficult to standardize, and the equipment may be provided by different manufacturers. Therefore, P-CSCF or SMF network elements cannot easily obtain the status of inter-satellite links by querying external systems.

[0318] Based on this, embodiments of this application provide a communication method, communication device, communication system, and storage medium, which obtains the status of inter-satellite paths through onboard UPF or onboard AGW, and then determines whether to enable UE-SAT-UE communication based on the status of the inter-satellite paths, thereby avoiding the problem of not being able to obtain the status of inter-satellite paths due to the inability to query external interfaces.

[0319] Please refer to Figure 5, which is a schematic diagram of a communication method provided in an embodiment of this application. The method shown in Figure 5 is executed interactively by onboard UPF1, onboard UPF2, SMF1, SMF2, P-CSCF1, and P-CSCF2. The method shown in Figure 5 can be applied to the application scenario shown in Figure 3. Onboard UPF1 corresponds to the UPF on the first satellite, and onboard UPF2 corresponds to the UPF on the second satellite. SMF1, SMF2, P-CSCF1, and P-CSCF2 are all network devices deployed on the ground. Onboard UPF1 is the first network element, onboard UPF2 is the second network element, SMF2 is the first session management function network element, SMF1 is the second session management function network element, P-CSCF1 is the first proxy call session control function network element, and P-CSCF2 is the second proxy call session control function. In this embodiment, P-CSCF1 is the calling UE, i.e., the proxy call session control function network element corresponding to UE1 shown in Figure 3, and P-CSCF2 is the proxy call session control function network element corresponding to the called UE. Similarly, onboard UPF1 is the UPF accessed by the calling UE, and onboard UPF2 is the UPF accessed by the called UE, i.e., the UPF accessed by UE2 as shown in Figure 3. UE1 is the first terminal device, UE2 is the second terminal device, SMF1 is responsible for managing onboard UPF1, and SMF2 is responsible for managing onboard UPF2. The method includes steps 501 to 510.

[0320] It should be noted that in one possible implementation, there may be a direct inter-satellite link between the onboard UPF1 and neighboring onboard UPFs. For example, onboard UPF1 and neighboring onboard UPFs may be co-orbiting or adjacent satellites in adjacent orbits, and their relative positions can be relatively stable, allowing for a direct inter-satellite link. In another possible implementation, there may not be a direct inter-satellite link between onboard UPF1 and neighboring onboard UPFs, but they can be reached via inter-satellite links from other satellites. For example, onboard UPF1 and neighboring onboard UPFs may be co-orbiting satellites, but separated by at least one other satellite. In this case, the inter-satellite path between onboard UPF1 and neighboring onboard UPFs passes through this at least one other satellite. Alternatively, the orbits of onboard UPF1 and neighboring onboard UPFs may be separated by at least one other orbit, and the route between onboard UPF1 and neighboring onboard UPFs needs to be relayed by satellites in the orbits of this at least one other satellite. Alternatively, the relationship between the onboard UPF1 and neighboring onboard UPFs can be a combination of the two relationships mentioned above, with the path between the onboard UPF1 and neighboring onboard UPFs passing through multiple satellites.

[0321] Low Earth Orbit (LEO) constellations typically consist of multiple satellite orbits, each containing multiple satellites. A single orbital layer (comprising multiple satellite orbits at the same altitude and inclination) often comprises hundreds or even thousands of satellites. In this scenario, supporting full mesh routing among thousands of satellites and selecting the optimal (or shortest) path is generally quite challenging. To simplify the algorithm, inter-satellite routing is usually configured only between neighboring satellites. This means that when satellites are too far apart (e.g., too many orbital gaps or too many satellites in the same direction of orbit), inter-satellite routing is usually not supported. Even if neighboring satellites are reachable via inter-satellite links, the excessive number of hops in these links leads to excessive path latency. Therefore, onboard UPFs are only configured with addresses of neighboring UPFs reachable via inter-satellite routing.

[0322] To monitor the path status between the onboard UPF1 and neighboring onboard UPFs, such as reachability, link latency, and packet loss rate, the onboard UPF1 can perform link status monitoring with configured neighboring UPFs. This monitoring can be based on protocols such as One-Way Active Measurement Protocol (OWAMP), Two-Way Active Measurement Protocol (TWAMP), and Packet Internet or Inter-Network Groper (PING). This monitoring can be periodic, occurring at each configured time interval. This periodic monitoring allows the onboard UPF to detect changes in path status. Alternatively, the monitoring can be bidirectional, where the onboard UPF1 and neighboring UPFs configure peers and independently initiate monitoring. Both can obtain path status information through their local monitoring. The situation of spaceborne UPF2 is similar to that of spaceborne UPF1, and will not be elaborated here.

[0323] 501. P-CSCF1 sends a request message to SMF1, and SMF1 receives the request message from P-CSCF1 accordingly.

[0324] P-CSCF1 receives a SIP Invite request from a first terminal device, which includes the identification information of a second terminal device. This identification information can be the IP address of the second terminal device, or other information used to identify it, such as an MSISDN (Mobile Subscriber International ISDN / PSTN Number), which is not limited here. Based on the SIP Invite request from the first terminal device, P-CSCF1 sends a request message to the SMF serving the first terminal device, i.e., SMF1. P-CSCF1 can send this request message after determining that the first terminal device is accessing via a regenerating satellite. This request message includes the identification information of the first terminal device. The request message also indicates the selection of an inter-satellite path. It should be noted that P-CSCF and SMF do not necessarily have a direct interface; that is, P-CSCF can send the above request message to SMF through other devices. For example, P-CSCF first sends a message to PCF, and then PCF sends the above request message to SMF. For example, in this embodiment, the request message sent by P-CSCF1 to PCF1, which provides services to UE1, includes an indication of selecting an inter-satellite path. Correspondingly, the request message sent by PCF1 to SMF1 includes indication information to instruct SMF1 to select an inter-satellite path.

[0325] Based on the request message, SMF1 determines that the onboard UPF1 accessed by the first terminal device is the UPF for the first terminal device to conduct a session. SMF1 can obtain the network element-level tunnel information of the onboard UPF1. This network element-level tunnel is the tunnel between the onboard UPF1 and other neighboring onboard UPFs (such as onboard UPF2). This network element-level tunnel information can be allocated or configured on the onboard UPF1 and sent to SMF1 by the onboard UPF1, or it can be configured on SMF1, and SMF1 obtains the tunnel information from the configuration information.

[0326] The request message only indicates the selection of inter-satellite paths, that is, inter-satellite paths are not established for the time being. Therefore, SMF can select only the onboard UPF1 and obtain the network element-level tunnel information of the onboard UPF1.

[0327] 502. SMF1 sends a response message to P-CSCF1, and P-CSCF1 receives the response message from SMF1 accordingly; wherein, the response message is a response message to the request message.

[0328] SMF1 sends the identification information and network element-level tunnel information of the onboard UPF1 to P-CSCF1 in response to the request message. In other words, SMF1 responds to the request message by sending a response message to P-CSCF1, which includes the identification information and network element-level tunnel information of the onboard UPF1.

[0329] 503. P-CSCF1 sends a call request to P-CSCF2, and P-CSCF2 receives the call request from P-CSCF1 accordingly.

[0330] After SMF1 determines the session UPF of the first terminal device, the P-CSCF corresponding to the calling UE, namely P-CSCF1, sends a call request to the P-CSCF corresponding to the called UE, namely P-CSCF2. This call request includes the IP address of the first terminal device, the identification information of the onboard UPF1, and the tunnel information of the onboard UPF1.

[0331] 504. P-CSCF2 sends a request message to SMF2, and SMF2 receives the request message from P-CSCF2 accordingly.

[0332] When P-CSCF2 determines that the second terminal device also accesses via a low-Earth orbit regenerable satellite, P-CSCF2 sends a request message to the SMF2 serving the second terminal device. This request message instructs the SMF2 to establish an inter-satellite path for the session between the first and second terminal devices, enabling data packets to be forwarded between them via satellite without traversing terrestrial network equipment. This request message includes the IP address of the first terminal device, the identification information of the onboard UPF1, and the tunnel information of the onboard UPF1.

[0333] It should be noted that, similar to P-CSCF1, P-CSCF2 can also send a request message to SMF2 through PCF2, which provides services to UE2. Please refer to the description in step 501 for details. The request message sent by P-CSCF2 to SMF2 differs from the request message sent by P-CSCF1 to SMF1 in step 501. The request message sent by P-CSCF1 to SMF1 is used to request SMF1 to determine the onboard UPF1 to which the first terminal device is accessed, while the request message sent by P-CSCF2 to SMF2 requests SMF2 to establish an inter-satellite path based on the identification information of the onboard UPF1.

[0334] 505. SMF2 obtains path status information.

[0335] SMF2 obtains path status information based on the identification information of the onboard UPF1. This path status information is used to indicate the status of the onboard link between the first network element deployed on the first NTN device and the second network element deployed on the second NTN device. In this embodiment, the first NTN device is the first satellite shown in Figure 3, and the first network element is the onboard UPF1; the second NTN device is the second satellite shown in Figure 3, and the second network element is the onboard UPF2. Therefore, this path status information is used to indicate the path status between onboard UPF1 and onboard UPF2.

[0336] Specifically, the path status information is used to indicate whether the inter-satellite link between satellite UPF1 and satellite UPF2 is reachable, the link latency of the inter-satellite link, and the link packet loss rate. For example, the path status information can be a path status value, meaning the status of the inter-satellite link between satellite UPF1 and satellite UPF2 can be represented by a specific numerical value. For instance, 1 bit can be used to represent whether the inter-satellite link is reachable; a path status value of 0 indicates that the inter-satellite link is unreachable, and a path status value of 1 indicates that the inter-satellite link is reachable. Another example is that the path status value can be the link latency or the link packet loss rate of the inter-satellite link; specific details are not limited here. The path status information can also be a set of multiple path status values, or the path status value can indicate whether the path status value is greater than or less than a preset threshold; specific details are not limited here. The path status information can also be a path availability indicator and a path unavailability indicator, where a path availability indicator indicates that the inter-satellite link between satellite UPF1 and satellite UPF2 is available, and a path unavailability indicator indicates that the inter-satellite link between satellite UPF1 and satellite UPF2 is unavailable. It should be noted that the availability of inter-satellite links primarily means that the inter-satellite links are reachable. Secondly, the reachability of inter-satellite links also includes that the latency of the inter-satellite links and / or the packet loss rate of the inter-satellite links are less than a threshold, but the specifics are not limited here.

[0337] In one possible implementation, SMF2 can instruct the onboard UPF2 via a path state subscription request to send a path state notification message to SMF2 upon entering SMF2's service area. See steps 500c and 500d for details.

[0338] Based on the identification information of the onboard UPF1, SMF2 determines the path status between onboard UPF2 and onboard UPF1 from the path status information between onboard UPF2 and multiple neighboring onboard UPFs included in the path status notification message, thereby obtaining path status information. Specifically, when multiple neighboring onboard UPFs include onboard UPF1, SMF2 obtains the path status between onboard UPF2 and onboard UPF1 from the path status information between onboard UPF2 and multiple Starlink onboard UPFs; when multiple neighboring onboard UPFs do not include onboard UPF1, SMF2 determines that the path status between onboard UPF2 and onboard UPF1 is unavailable.

[0339] In another possible implementation, SMF2 sends a query request message to the onboard UPF2. This query request message includes the identification information of onboard UPF1. This message instructs onboard UPF2 to query the path status between onboard UPF2 and onboard UPF1 based on the identification information of onboard UPF1. Upon receiving the query request message, onboard UPF2 obtains the identification information of onboard UPF1. If onboard UPF2 has not configured onboard UPF1 as a neighboring onboard UPF, it can be assumed that there is no inter-satellite path reachable between them; in this case, the path between onboard UPF2 and onboard UPF1 is unavailable. If onboard UPF2 has configured onboard UPF1 as a neighboring onboard UPF, then onboard UPF2 obtains the path status information based on the monitoring results. In response to the query request message, onboard UPF2 sends a first response message to SMF2. If the inter-satellite path between UPF1 and UPF2 is reachable, the first response message includes path status information; if the inter-satellite path between UPF1 and UPF2 is unreachable, the first response message includes a path unavailable indication.

[0340] It should be noted that SMF2 can also obtain path status information by executing step 506. Specifically, while sending the first traffic splitting rule to the onboard UPF2, SMF2 also sends indication information. This indication information is used to instruct the onboard UPF2 to split traffic according to the first traffic splitting rule if the inter-satellite link between onboard UPF2 and onboard UPF1 is available, and return a path availability indication. If the inter-satellite link is unavailable, a path unavailable indication is returned. In this case, the onboard UPF2 can configure threshold information for determining whether the path is available or receive threshold information from SMF2, such as a latency threshold and a packet loss rate threshold. When the latency of the inter-satellite path is less than the latency threshold and the packet loss rate of the inter-satellite path is less than the packet loss rate threshold, the onboard UPF2 determines that the path is available. In this case, the onboard UPF2 first determines whether the inter-satellite path between onboard UPF2 and onboard UPF1 is available. If it is available, the first traffic splitting rule is installed and a success indication is sent in the response message; if it is unavailable, the first traffic splitting rule is not installed and a failure indication is sent in the response message.

[0341] In this embodiment of the application, by obtaining path status information from the onboard UPF2, the SMF2 does not need to query external systems, thereby avoiding the problem that the path status of inter-satellite links cannot be queried due to the lack of standardization of external interfaces.

[0342] 506. SMF2 sends the first diversion rule to the onboard UPF2, and correspondingly, the onboard UPF2 receives the first diversion rule from SMF2.

[0343] In one possible implementation, when SMF2 determines that the path between onboard UPF1 and onboard UPF2 is available, SMF2 sends a first traffic splitting rule to onboard UPF2. This first traffic splitting rule instructs onboard UPF2 to use the tunnel information of onboard UPF1 to send a first data packet to onboard UPF1, wherein the destination address of the first data packet is the IP address of the first terminal device, and the first data packet is obtained by onboard UPF2 from the second terminal device. Sending the first data packet to UPF1 using the tunnel information of UPF1 means encapsulating the first data packet within the tunnel between UPF1 and UPF2 using the tunnel information of UPF1. For example, assuming an IP-in-IP tunnel is used between UPF1 and UPF2, the tunnel information of UPF1 includes the IP address of UPF1, and optionally also includes tunnel type information, i.e., the tunnel type is IP-in-IP. In this case, sending the first data packet using the tunnel information of UPF2 means adding a tunnel header to the first data packet. This tunnel header is an IP header, and the destination address of this IP header is the IP address of UPF1, and the source address is the IP address of UPF2. The specific sending method is related to the tunnel used between UPF1 and UPF2.

[0344] Specifically, SMF2 instructs the onboard UPF2 to forward the IMS media stream data packets sent from the second terminal device to the first terminal device to the onboard UPF1. This means the first traffic splitting rule also includes protocol type information, with the protocol type indicating an IMS media stream. Based on the tunnel information of the onboard UPF1, the onboard UPF2 establishes a network element-level tunnel with the onboard UPF1. SMF2 instructs the onboard UPF2 to forward the IMS media stream data packets sent to the first terminal device to the onboard UPF1 through this network element-level tunnel. SMF2 needs to send the IP address of the first terminal device and the tunnel address of the onboard UPF1 to the onboard UPF2, so that the onboard UPF2 can determine the media stream data packets to be sent to the first terminal device based on the IP address and protocol type. Therefore, the first traffic splitting rule includes the IP address of the first terminal device and the tunnel information of the onboard UPF1. Simultaneously, the onboard UPF2 forwards the data packets received from the first terminal device to the second terminal device. Furthermore, the first traffic splitting rule also includes the IP address of the second terminal device to determine that the data packets originate from the second terminal device.

[0345] The first diversion rule can also be used to instruct the onboard UPF2 to allocate tunnel information for the onboard UPF2, and send the tunnel information of the onboard UPF2 to SMF2 in the response message.

[0346] In another possible implementation, SMF2 is unsure whether the path status between onboard UPF1 and onboard UPF2 is available. In this case, SMF2 sends an indication message to onboard UPF2 while sending the first diversion rule. Please refer to the description in step 505 for details, which will not be repeated here.

[0347] In one possible embodiment, SMF2 can also send a second traffic splitting rule to the onboard UPF2. This second traffic splitting rule is used to instruct the second network element to send the first data packet to the session anchor. The destination address of the first data packet is the IP address of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The session anchor provides services to the second terminal device. The session anchor is the user plane anchor of the second terminal device. In 5G, the session anchor is PSA. The second network element provides services to the second terminal device. The session anchor is deployed on the first terrestrial network, which is the terrestrial core network.

[0348] Specifically, the second traffic splitting rule instructs the onboard UPF2 to send the first data packet to PSA2, which is the session anchor point for the second terminal device deployed on the first terrestrial network, which is the terrestrial core network. Based on the second traffic splitting rule, the onboard UPF2 sends the IMS media stream data packet destined for the first terminal device to PSA1 via PSA2, and then PSA1 forwards the first data packet to the onboard UPF1. Simultaneously, the onboard UPF2 sends the data packets received from PSA2 to the second terminal device.

[0349] In one implementation, SMF2 sends a first indication message while sending the first and second diversion rules. The first indication message is used to instruct the onboard UPF2 to decide, based on the path status, whether to use the first diversion rule or the second diversion rule to divert the IMS media stream data packets.

[0350] In this embodiment of the application, by sending the first diversion rule, the second diversion rule and the first indication information, the onboard UPF2 can dynamically select the inter-satellite path or the ground path according to the path status, thereby selecting the optimal path and giving the user a better call experience.

[0351] 507. SMF2 sends a response message or notification message to P-CSCF2, and P-CSCF2 receives the response message or notification message from SMF2 accordingly.

[0352] The response message sent by SMF2 to P-CSCF2 is the response message corresponding to the request message sent by P-CSCF2 to SMF2 in step 504. This response message is used to indicate whether the inter-satellite path has been successfully established. In one embodiment described above, SMF2 makes a judgment based on the path status information. If the path status information indicates that the path status between onboard UPF1 and onboard UPF2 is available, then SMF2 sends a first traffic splitting rule to establish the inter-satellite path. Furthermore, the response message includes the tunnel information of onboard UPF2 and can also indicate that the inter-satellite path has been successfully established. If the path status information indicates that the path status between onboard UPF1 and onboard UPF2 is unavailable, then the response message includes an inter-satellite path unavailability indication. In another implementation, SMF2 sends an indication message while sending the first diversion rule, instructing the onboard UPF2 to divert traffic according to the first diversion rule when the inter-satellite path between onboard UPF2 and onboard UPF1 is available. SMF2 receives a response message from onboard UPF2. If the response message indicates success, SMF2 sends a response message to P-CSCF2 including the tunnel message of onboard UPF2. Alternatively, if the response message indicates failure, SMF2 sends a response message to P-CSCF2 including an indication that the inter-satellite path is unavailable.

[0353] If SMF2 indicates that the inter-satellite path has been successfully established, P-CSCF2 instructs the second terminal device to send the media stream directly to the first terminal device. That is, P-CSCF2 carries the IP address of the first terminal device in the message sent to the second terminal device.

[0354] 508. P-CSCF2 sends a call response to P-CSCF1, and P-CSCF1 receives the call response from P-CSCF2 accordingly.

[0355] The call response is the response message corresponding to the call request in step 503. If this session supports inter-satellite links, i.e., SMF2 indicates a successful inter-satellite path establishment, the call response includes the identification information of the onboard UPF2 and its tunnel information, as well as the IP address of the second terminal. The call response also includes a path indication, i.e., the path used by the media stream between the first and second terminals. If this session supports inter-satellite links, the path indication is used to indicate that the media stream between the first and second terminals uses an inter-satellite path, i.e., it is forwarded via the inter-satellite link between onboard UPF1 and onboard UPF2.

[0356] 509. P-CSCF1 sends a request message to SMF1, and SMF1 receives the request message from P-CSCF1 accordingly.

[0357] The function of this request message is similar to that of the request message sent by P-CSCF2 to SMF2 in step 504. Specifically, P-CSCF1 sends this request message to SMF1 to request SMF1 to establish an inter-satellite path for the session between the first and second terminal devices, enabling data packets to be forwarded between them via satellite without traversing terrestrial network equipment. This request message includes the identification information of the onboard UPF2, the tunnel information of the onboard UPF2, and the identification information of the second terminal device. The request message may also include the identification information of the first terminal device and the protocol number of the media stream data packets between the first and second terminal devices. See step 504 for details.

[0358] 510. SMF1 sends the fifth diversion rule to the onboard UPF1, and correspondingly, the onboard UPF1 receives the fifth diversion rule from SMF1.

[0359] Step 510 is similar to step 506 in this embodiment, but the fifth diversion rule is in the opposite direction to the first diversion rule. That is, the fifth diversion rule instructs the onboard UPF1 to use the tunnel information of the onboard UPF2 to send the fifth data packet to the onboard UPF2, where the fifth data packet is a media stream data packet sent from the first terminal device to the second terminal device. Specifically, see step 506. In step 506, the first diversion rule replaces onboard UPF2 with onboard UPF1, onboard UPF1 with onboard UPF2, the first terminal with the second terminal, the second terminal with the first terminal, SMF2 with SMF1, the first diversion rule with the fifth diversion rule, and the first data packet with the fifth data packet. Further details are omitted here.

[0360] In this embodiment, since the SMF queries the inter-satellite path through the onboard UPF and then decides whether to enable UE-SAT-UE communication based on the reachability of the inter-satellite path, the SMF does not need to query the external system to obtain the inter-satellite path status, thus avoiding the problem of not being able to query and obtain the reachability of the inter-satellite path.

[0361] Optionally, the embodiment shown in FIG5 further includes step 500a. Step 500a may be performed before step 501.

[0362] 500a, SMF1 sends a path state subscription request to the onboard UPF1, and correspondingly, the onboard UPF1 receives the path state subscription request from SMF1.

[0363] When the onboard UPF1 enters the service area of ​​SMF1, SMF1 sends a path status subscription request to the onboard UPF1. This request requests the status of the inter-satellite paths between the onboard UPF1 and all configured neighboring onboard UPFs. This path status subscription request can also request a path status change report when the path status between the onboard UPF1 and neighboring onboard UPFs changes. For example, when the status of the inter-satellite path between the onboard UPF1 and any configured neighboring onboard UPF changes from reachable to unreachable, or from unreachable to reachable, a path status change report is sent to SMF1. As another example, SMF1 can configure a preset threshold in the path status subscription request. When the link latency or link packet loss rate of the inter-satellite link between the onboard UPF and any configured neighboring onboard UPF changes from less than the preset threshold to greater than the preset threshold, or from greater than the preset threshold to less than the preset threshold, a path status change report and the latest path status information are sent to SMF1.

[0364] Optionally, the embodiment shown in Figure 5 further includes step 500b. Step 500b may be performed after step 500a.

[0365] 500b. The onboard UPF1 sends a path status notification message to the SMF1, and the corresponding SMF1 receives the path status notification message from the onboard UPF1.

[0366] In response to the path state subscription request, the onboard UPF1 sends the path state notification message to SMF1, carrying the status of the inter-satellite paths between the onboard UPF1 and all configured neighboring onboard UPFs.

[0367] Optionally, the embodiment shown in Figure 5 further includes step 500c. Step 500c may be performed before step 501.

[0368] 500c and SMF2 send path state subscription requests to the onboard UPF2, and the onboard UPF2 receives the path state subscription requests from SMF2 accordingly.

[0369] Step 500c is similar to step 500a in this embodiment, and will not be described in detail here.

[0370] Optionally, the embodiment shown in Figure 5 further includes step 500d. Step 500d may be performed after step 500c.

[0371] 500d, the onboard UPF2 sends a path status notification message to the SMF2, and the SMF2 receives the path status notification message from the onboard UPF2.

[0372] Step 500d is similar to step 500b in this embodiment, and will not be described in detail here.

[0373] Optionally, the embodiment shown in FIG5 further includes step 509a. Step 509a may be performed after step 509.

[0374] 509a and SMF1 obtain path status information;

[0375] Step 509a is similar to step 505 in this embodiment, and will not be described in detail here.

[0376] In practical applications, because the satellite is constantly moving, the path status between onboard UPF1 and onboard UPF2 may change. For example, the path status between onboard UPF1 and onboard UPF2 may change from available to unavailable. Conversely, the path status between onboard UPF1 and onboard UPF2 may change from unavailable to available.

[0377] The following example illustrates the change in path status between onboard UPF1 and onboard UPF2 from available to unavailable. Please refer to Figure 6, which is another schematic diagram of the communication method provided in this embodiment. The method shown in Figure 6 is executed interactively by onboard UPF1, onboard UPF2, SMF1, SMF2, P-CSCF1, and P-CSCF2. The method shown in Figure 6 can be applied to the application scenario shown in Figure 3. Onboard UPF1 corresponds to the UPF on the first satellite, and onboard UPF2 corresponds to the UPF on the second satellite. SMF1, SMF2, P-CSCF1, and P-CSCF2 are all network devices deployed on the ground. Onboard UPF1 is the first or third network element, onboard UPF2 is the second or fourth network element, SMF2 is the first session management function network element, SMF1 is the second session management function network element, P-CSCF1 is the first proxy call session control function network element, and P-CSCF2 is the second proxy call session control function. In this embodiment, UE1 is a first terminal device, UE2 is a second terminal device, SMF1 is responsible for managing the onboard UPF1, and SMF2 is responsible for managing the onboard UPF2. The method includes steps 601 to 606.

[0378] 601. The onboard UPF1 sends a path status change report to the SMF1, and the corresponding SMF1 receives the path status change report from the onboard UPF1; wherein, the path status change report may be first information used to indicate that the path status between the first network element and the second network element has changed.

[0379] Based on step 500a in the embodiment shown in Figure 5, SMF1 instructs onboard UPF1 to send a path status change report when the path status between onboard UPF1 and onboard UPF2 changes, via a path status subscription request. In this embodiment, SMF1 determines that the path status between onboard UPF1 and onboard UPF2 has changed from available to unavailable based on the path status change report.

[0380] 602. SMF1 sends a notification message to P-CSCF1, and P-CSCF1 receives the notification message from SMF1 accordingly.

[0381] When the path status between onboard UPF1 and onboard UPF2 changes, SMF1 sends a notification message to SMF1.

[0382] Optionally, the notification message includes path status change information. This path status change information is provided by SMF1 to P-CSCF1 based on the path status change report, indicating whether the path between onboard UPF1 and onboard UPF2 is available or unavailable; in other words, this path status change information is used to indicate whether the inter-satellite path is available.

[0383] When path status change information indicates that a path between onboard UPF1 and onboard UPF2 is unavailable, the notification message includes a path unavailable indication. Similarly, when path status change information indicates that a path between onboard UPF1 and onboard UPF2 is available, the notification message includes a path available indication.

[0384] 603. SMF1 sends the second diversion rule to the onboard UPF1, and correspondingly, the onboard UPF1 receives the second diversion rule from SMF1.

[0385] When the inter-satellite path between onboard UPF1 and onboard UPF2 is unavailable, SMF1 instructs onboard UPF1 to switch the transmission path between the first terminal device and the second terminal device from the inter-satellite path to a ground path. SMF1 sends a second traffic splitting rule to onboard UPF1. This second traffic splitting rule can be referred to the description in step 506 of the embodiment shown in Figure 5, and will not be repeated here.

[0386] Optionally, SMF1 may also instruct the onboard UPF1 to delete the first traffic splitting rule when sending the second splitting rule.

[0387] The onboard UPF1 receives the second traffic splitting rule and cancels the first traffic splitting rule according to the instruction. That is, the onboard UPF1 no longer sends the data packet destined for the IP address of the second terminal device to the onboard UPF2 through the tunnel information of the onboard UPF2, but instead sends the data packet to PSA1.

[0388] Optionally, SMF1 can remove the onboard UPF1 from the session path, allowing the first terminal device to send uplink data packets to the access network device on the first satellite, and the access network device on the first satellite to directly send the uplink data packets sent by the first terminal device to PSA1.

[0389] 604. P-CSCF1 sends a path switching notification to P-CSCF2, and P-CSCF2 receives the path switching notification from P-CSCF1 accordingly.

[0390] P-CSCF1 sends a handover path notification to P-CSCF2 to instruct P-CSCF2 to switch the inter-satellite path to a ground path. Specifically, this handover path notification may be a fourth message or carried within a fourth message. This handover path notification is used to indicate a switch from the first path to the second path, where the first path is the path from the first terminal device to the second terminal device via the third and fourth network elements, i.e., the path from UE1 to UE2 via onboard UPF1 and UPF2; the second path is the path from the first terminal device to the second terminal device via a session anchor point, i.e., the path from UE1 to UE2 via PSA1 and PSA2.

[0391] It should be understood that the first path and the second path in the embodiments of this application are used to represent the nodes through which the data packet is transmitted, and do not limit the direction of transmission. For example, in the first path, the data packet can travel from the first terminal device to the second terminal device through the third network element and the fourth network element, or it can travel from the second terminal device to the first terminal device through the fourth network element and the third network element; the specific path is not limited here.

[0392] It should be noted that the timing between steps 603 and 604 is not limited in the embodiments of this application. Step 603 can be executed before or after step 604, and the specific execution is not limited here.

[0393] 605. P-CSCF2 sends a path switching notification to SMF2, and SMF2 receives the path switching notification from P-CSCF2 accordingly.

[0394] P-CSCF2 sends a path switching notification to SMF2 to instruct SMF2 to switch the inter-satellite path to a ground path. Specifically, this path switching notification can be first or fourth information indicating the switching of the transmission path between the first and second network elements, or it can carry first or fourth information indicating the switching of the transmission path between the first and second network elements. The path switching notification indicates the switching of the first path to the second path. The first path is the path from the first terminal device to the second terminal device via the third and fourth network elements, i.e., the path from the first terminal device to the second terminal device via onboard UPF1 and UPF2; the second path is the path from the first terminal device to the second terminal device via the session anchor point, i.e., the path from the first terminal device to the second terminal device via PSA1 and PSA2.

[0395] 606. SMF2 sends the second diversion rule to the onboard UPF2, and correspondingly, the onboard UPF2 receives the second diversion rule from SMF2.

[0396] Step 606 is similar to step 603 in this embodiment, and will not be described in detail here.

[0397] In this embodiment of the application, the continuity of call services is ensured and call service interruption is prevented by switching to a ground path when the inter-satellite path changes from available to unavailable.

[0398] It should be understood that the embodiment shown in Figure 6 uses the example of the path status between onboard UPF1 and onboard UPF2 changing from an available state to an unavailable state. In practical applications, the path status between onboard UPF1 and onboard UPF2 can also change from an unavailable state to an available state. In this case, step 603 in the embodiment shown in Figure 6 is replaced by SMF1 sending a first diversion rule to onboard UPF1, so that onboard UPF1 uses the inter-satellite path to transmit data packets according to the first diversion rule. Similarly, step 606 is replaced by SMF2 sending a first diversion rule to onboard UPF2. At the same time, the path status change report in step 601 is used to indicate that the path status between onboard UPF1 and onboard UPF2 has changed from an unavailable state to an available state.

[0399] When switching from an inter-satellite path to a ground path, the ground path can also be transmitted through a ground access gateway deployed on a second ground network. Please refer to Figure 7, which is another schematic diagram of the communication method provided in this application embodiment. The method shown in Figure 7 is interactively executed by UE1, UE2, onboard UPF1, onboard UPF2, SMF1, SMF2, ground AGW1, ground AGW2, P-CSCF1, and P-CSCF2. The method shown in Figure 7 can be applied to the application scenario shown in Figure 3. Onboard UPF1 corresponds to the UPF on the first satellite, onboard UPF2 corresponds to the UPF on the second satellite, and SMF1, SMF2, ground AGW1, ground AGW2, P-CSCF1, and P-CSCF2 are all network devices deployed on the ground. The onboard UPF1 is the first or third network element, the onboard UPF2 is the second or fourth network element, the SMF2 is the first session management function network element, the SMF1 is the second session management function network element, the P-CSCF1 is the first proxy call session control function network element, the P-CSCF2 is the second proxy call session control function network element, the ground access gateway is the ground AGW1 or the ground AGW2, and the second ground network is the IMS network. In this embodiment, UE1 is the first or third terminal device, UE2 is the second or fourth terminal device, SMF1 is responsible for managing the onboard UPF1, and SMF2 is responsible for managing the onboard UPF2. The method includes steps 701 to 712.

[0400] 701. The onboard UPF1 sends a path status change report to the SMF1, and the corresponding SMF1 receives the path status change report from the onboard UPF1; wherein, the path status change report may be first information used to indicate that the path status between the first network element and the second network element has changed.

[0401] 702. SMF1 sends a notification message to P-CSCF1, and P-CSCF1 receives the notification message from SMF1 accordingly.

[0402] Steps 701 to 702 in this embodiment are similar to steps 601 to 602 in the embodiment shown in Figure 6 above, and will not be described in detail here.

[0403] 703. P-CSCF1 Select and configure ground AGW1.

[0404] P-CSCF1 selects and configures ground AGW1 to establish a media stream path for communication between UE1 and UE2. Ground AGW1 provides IMS communication services to UE1.

[0405] 704. P-CSCF1 sends a path switching notification to P-CSCF2, and P-CSCF2 receives the path switching notification from P-CSCF1 accordingly.

[0406] P-CSCF1 sends a switching path notification to P-CSCF2 to instruct P-CSCF2 to switch the inter-satellite path to a terrestrial path. Specifically, this switching path notification may be a fourth piece of information or carried within a fourth piece of information. This switching path notification is used to indicate a switch from the first path to the second path, where the first path is the path from the first terminal device to the second terminal device via the third and fourth network elements, i.e., the path from UE1 to UE2 via onboard UPF1 and onboard UPF2; the second path is the path from the first terminal device to the second terminal device via a terrestrial access gateway, i.e., the path from the first terminal device to the second terminal device via terrestrial AGW1 and terrestrial AGW2.

[0407] 705. P-CSCF1 sends a second indication message to UE1, and UE1 receives the second indication message from P-CSCF1 accordingly.

[0408] P-CSCF1 sends a second instruction message to UE1. When UE1 executes the second instruction message, the call path from UE1 to UE2 will be switched from the first path to the second path. The first path is the path from the first terminal device to the second terminal device through the third and fourth network elements, that is, the path from UE1 to UE2 through the satellite UPF1 and satellite UPF2. The second path is the path from the first terminal device to the second terminal device through the terrestrial access gateway, that is, the path from UE1 to UE2 through the terrestrial AGW1 and terrestrial AGW2.

[0409] Specifically, the second instruction information is used to instruct UE1 to change the destination address of the data packet sent to UE2 from the IP address of UE2 to the IP address of the ground AGW1, thereby changing the transmission path of UE1 from the first path to the second path.

[0410] It should be noted that this embodiment does not limit the timing between steps 704 and 705. Step 704 can be executed before or after step 705; the specific timing is not limited here.

[0411] 706. P-CSCF2 Select and configure ground AGW2.

[0412] Step 706 is similar to step 703 in this embodiment, and will not be described in detail here.

[0413] 707. P-CSCF2 sends a second indication message to UE2, and UE2 receives the second indication message from P-CSCF2 accordingly.

[0414] Step 707 is similar to step 705 in this embodiment, and will not be described in detail here.

[0415] 708. P-CSCF2 sends a switching path response to P-CSCF1, and P-CSCF1 receives the switching path response from P-CSCF2 accordingly.

[0416] The path switching response is the response message of the path switching notification shown in step 704. The path switching response carries the IP address of the ground access gateway, that is, the IP address of ground AGW2.

[0417] 709. P-CSCF2 sends the first service flow information to SMF2, and SMF2 receives the first service flow information from P-CSCF2 accordingly.

[0418] P-CSCF2 sends first service flow information to SMF2. This first service flow information is used to indicate the QoS requirements of the media stream transmitted over the ground to SMF2. Specifically, this first service flow information is included in the second information, and the first service flow information may include a five-tuple. The first service flow is the service flow between the second terminal device and the ground access gateway, i.e., the service flow between UE2 and the ground AGW2.

[0419] 710. SMF2 sends the third diversion rule to the onboard UPF2, and correspondingly, the onboard UPF2 receives the third diversion rule from SMF2.

[0420] SMF2 sends a third traffic splitting rule to the onboard UPF2. This third traffic splitting rule is used to instruct the second network element to send the third data packet from the second terminal device to the session anchor point. The third data packet is the data packet sent by the second terminal device to the ground access gateway (i.e., the ground AGW2).

[0421] Optionally, in response to the service flow information, SMF2 sends a third traffic splitting rule to the onboard UPF2.

[0422] Specifically, the third traffic splitting rule is used to instruct the onboard UPF2 to send the third data packet from UE2 to PSA2. This third data packet is sent by UE2 to the ground AGW2 through the onboard UPF2 and PSA2, meaning that the destination address of the third data packet is the IP address of the ground AGW2.

[0423] Optionally, SMF2 can also be configured with a fourth traffic splitting rule, which is used to instruct the second network element to send the fourth data packet from the session anchor point to the second terminal device. The fourth data packet is a data packet sent by the terrestrial access gateway to the second terminal device.

[0424] Specifically, the fourth traffic splitting rule is used to instruct the onboard UPF2 to receive the fourth data packet from PSA2. This fourth data packet is sent to UE2 by the ground AGW2 through PSA2 and the onboard UPF2, meaning that the destination address of the fourth data packet is the IP address of UE2.

[0425] Alternatively, in another optional implementation, SMF2 may also remove the onboard UPF2 from the call path, that is, instruct PSA2 to directly send the data packets received from the ground AGW2 and sent to UE2 to the onboard base station (i.e., the base station deployed on the same satellite as the onboard UPF2), and instruct the onboard base station to send the data packets received from UE2 and sent to the ground AGW2 to PSA2.

[0426] 711. P-CSCF1 sends the second service flow information to SMF1, and SMF1 receives the second service flow information from P-CSCF1 accordingly.

[0427] The second service flow information is the service flow information between the first terminal device and the ground access gateway, that is, the service flow information between UE1 and ground AGW1.

[0428] Step 711 is executed after step 704, that is, P-CSCF1 triggers step 710 after receiving the response message of the path switching notification message sent by P-CSCF2 in step 704.

[0429] 712. SMF1 sends the sixth diversion rule to the onboard UPF1, and correspondingly, the onboard UPF1 receives the sixth diversion rule from SMF1.

[0430] Step 712 is similar to step 710 in this embodiment, and will not be described in detail here. The sixth diversion rule in step 712 is similar to the third diversion rule, but the sixth diversion rule is in the opposite direction to the third diversion rule, and will not be described in detail here.

[0431] It should be understood that the embodiment shown in Figure 7 takes the change of the path status between onboard UPF1 and onboard UPF2 from an available state to an unavailable state as an example. In practical applications, the path status between onboard UPF1 and onboard UPF2 can also change from an unavailable state to an available state. In this case, step 712 in the embodiment shown in Figure 7 is changed to SMF1 sending a first diversion rule to onboard UPF1, so that onboard UPF1 can use the inter-satellite path to transmit data packets according to the first diversion rule. Similarly, step 710 is changed to SMF2 sending a fifth diversion rule to onboard UPF2. At the same time, the path status change report in step 701 is used to indicate that the path status between onboard UPF1 and onboard UPF2 has changed from an unavailable state to an available state. If the onboard UPF is deleted in step 712 or step 710, then the onboard UPF should be reinserted, that is, the base station is notified to send uplink data packets to the onboard UPF, and the ground PSA is notified to send downlink data packets to the onboard UPF.

[0432] It should be understood that the embodiments shown in Figures 6 and 7 are described using the example of the onboard UPF1 sending a path status report. In practical applications, the onboard UPF2 can also send the path status report, or both onboard UPF1 and onboard UPF2 can send path status reports. When both onboard UPF1 and onboard UPF2 send path status reports, if the handover process has already been triggered, the SMF or P-CSCF may not process the duplicate trigger.

[0433] In the embodiments shown in Figures 6 and 7, path switching requires control plane involvement. Please refer to Figure 8, which is another schematic diagram of the communication method provided in this application embodiment. In this method, during session establishment, two media stream paths can be established simultaneously between UE1 and UE2. The UE monitors the paths and determines the path used to send media stream data packets based on the monitoring results.

[0434] The method shown in Figure 8 is executed interactively by UE1, UE2, onboard UPF1, onboard UPF2, SMF1, SMF2, ground AGW1, ground AGW2, P-CSCF1, and P-CSCF2. The method shown in Figure 8 can be applied to the application scenario shown in Figure 3. Onboard UPF1 corresponds to the UPF on the first satellite, and onboard UPF2 corresponds to the UPF on the second satellite. SMF1, SMF2, ground AGW1, ground AGW2, P-CSCF1, and P-CSCF2 are all network devices deployed on the ground. Onboard UPF1 is the first or third network element, onboard UPF2 is the second or fourth network element, SMF2 is the first session management function network element, SMF1 is the second session management function network element, P-CSCF1 is the first proxy call session control function network element, P-CSCF2 is the second proxy call session control function network element, the ground access gateway is ground AGW1 or ground AGW2, and the second ground network is the IMS network. In this embodiment, UE1 is a first terminal device or a third terminal device, UE2 is a second terminal device or a fourth terminal device, SMF1 is responsible for managing the onboard UPF1, and SMF2 is responsible for managing the onboard UPF2. The method includes steps 801 to 813.

[0435] 801. P-CSCF1 obtains the identification information of the onboard UPF1.

[0436] The implementation of step 801 can refer to steps 501 to 502 in the embodiment shown in Figure 5 above, and will not be repeated here.

[0437] 802, P-CSCF1 is configured with ground AGW1.

[0438] In this embodiment, step 802 is similar to step 703 in the embodiment shown in Figure 7 above, and the specific details are not limited here.

[0439] 803. P-CSCF1 sends a call request to P-CSCF2, and P-CSCF2 receives the call request from P-CSCF1 accordingly.

[0440] The call request includes the identification information of the onboard UPF1, the IP address of the first terminal device, the tunnel information of the onboard UPF1, and the IP address of the ground AGW1.

[0441] 804, P-CSCF2 is configured with ground AGW2.

[0442] In this embodiment, step 804 is similar to step 706 in the embodiment shown in Figure 7 above, and the specifics are not limited here.

[0443] 805. P-CSCF2 sends a request message to SMF2, and SMF2 receives the request message from P-CSCF2 accordingly.

[0444] In response to the request message, SMF2 establishes both inter-satellite paths and ground paths. The method for establishing inter-satellite paths can be referred to step 505 in the embodiment shown in Figure 5 and step 708 in Figure 7, and will not be repeated here.

[0445] 806. SMF2 sends the first and third traffic splitting rules to the onboard UPF2, and the onboard UPF2 receives the first and third traffic splitting rules from SMF2 accordingly.

[0446] SMF2 sends two sets of traffic splitting rules to the onboard UPF2, enabling the onboard UPF2 to transmit data using either the first or third traffic splitting rule based on the transmission path determined by UE2.

[0447] That is, regardless of whether the inter-satellite path between UPF1 and UPF2 is currently available, SMF2 simultaneously sends the first and third diversion rules to UPF2.

[0448] 807. SMF2 sends a response message or notification message to P-CSCF2, and P-CSCF2 receives the response message or notification message from SMF2 accordingly.

[0449] In the response or notification message, SMF2 includes tunneling information for the onboard UPF2. In this step, regardless of whether an inter-satellite path between onboard UPF1 and onboard UPF2 is available, SMF2 includes the tunneling information for onboard UPF2 in the response message.

[0450] In one possible implementation, SMF2 may determine whether the inter-satellite path is available before sending a response message to P-CSCF2. The specific method for determining the availability of the inter-satellite path can be found in step 507 of the embodiment shown in Figure 5. If the inter-satellite path is available, SMF2 may include an indication of its availability in the response message or notification message.

[0451] 808. P-CSCF2 sends a call signaling message to UE2, and UE2 receives the call signaling message from P-CSCF2 accordingly.

[0452] P-CSCF2 sends a call signaling message to UE2. This message includes the IP address of the third terminal device and the IP address of the terrestrial access gateway; that is, the call signaling message includes the IP address of UE1 and the IP address of the terrestrial AGW2. The IP address of the third terminal device indicates the first path, and the IP address of the terrestrial access gateway indicates the second path. The first path is the path from the third terminal device to the fourth terminal device via the third and fourth network elements, i.e., the path from UE1 to UE2 via the onboard UPF1 and UPF2. The second path is the path from the third terminal device to the fourth terminal device via the terrestrial access gateway, i.e., the path from UE1 to UE2 via the terrestrial AGW1 and AGW2.

[0453] Optionally, the call signaling may also include third indication information, which is used to instruct UE2 to transmit data using the first path or the second path based on the path status of the first path and the second path.

[0454] As an example, if the path status of the first path is available, then UE2 uses the first path to transmit data; if the path status of the first path is unavailable, then UE2 uses the second path to transmit data.

[0455] Optionally, the call signaling also includes a path selection strategy. This strategy is used by UE1 to select a path. The path selection strategy includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold. The initial path indication indicates the path initially used by UE2, and the path priority indicates the preferred path between the first and second paths. The path priority can also be used to indicate the selection of a path with low latency or a path with low packet loss rate; the specific choice is not limited here. For example, if P-CSCF2 receives an indication from SMF2 that the first path (i.e., the inter-satellite path) is available, P-CSCF2 can instruct the UE to initially use the first path in the call signaling. The path latency threshold and path packet loss rate threshold included in the path selection strategy are used to monitor path availability; that is, when the path latency and path packet loss rate are less than the path latency threshold and path packet loss rate threshold, respectively, it indicates that the path is available. When the path is available, path selection is then performed according to the path priority. For example, if both the first and second paths are available, and the first path has a higher priority, then the first path is selected. As another example, if the path selection strategy instructs the selection of the path with lower latency, and path monitoring indicates that the second path has even lower latency, then the second path is selected.

[0456] Optionally, the call signaling may also include a fourth indication information, which is used to instruct UE2 to perform path monitoring on the first path and the second path, thereby obtaining the path status of the first path and the second path.

[0457] 809. P-CSCF2 sends a call response to P-CSCF1, and P-CSCF1 receives the call response from P-CSCF2 accordingly.

[0458] The call response is the response message corresponding to the call request in step 803. This response message carries information about the ground path and the inter-satellite path. The inter-satellite path information includes: the identification information of the onboard UPF2, the IP address of UE2, and the tunnel information of the onboard UPF2. The ground path information includes: the address of the ground AGW2. This message may also indicate the simultaneous establishment of both the ground path and the inter-satellite path. This message may also include the path selection strategy described in step 808.

[0459] 810. P-CSCF1 sends a request message to SMF1, and SMF1 receives the request message from P-CSCF1 accordingly.

[0460] 811. SMF1 sends the fifth and sixth traffic splitting rules to the onboard UPF1, and the onboard UPF1 receives the fifth and sixth traffic splitting rules from SMF1 accordingly.

[0461] 812. SMF1 sends a response message to P-CSCF1, and P-CSCF1 receives the response message from SMF1 accordingly.

[0462] 813. P-CSCF1 sends a call signaling to UE1, and UE1 receives the call signaling from P-CSCF1 accordingly.

[0463] Steps 810 to 813 are similar to steps 805 to 808 in this embodiment, and will not be described in detail here.

[0464] After establishing the first and second paths, the terminal device monitors the first and / or second paths and selects a path based on the path selection strategy and the monitoring results. For example, if the selection strategy prioritizes the first path, then when the first path is available, the terminal device will use the first path to send data packets.

[0465] In this embodiment, two paths are created during call setup: a first path and a second path. The terminal device determines the path to send media stream data packets based on the monitoring results of the first path and / or the second path and the path selection strategy. This reduces transmission latency and packet loss, and allows for dynamic selection of inter-satellite or terrestrial paths based on path status, thereby selecting the optimal path and providing users with a better call experience.

[0466] Optionally, the embodiment shown in FIG8 further includes step 800a. Step 800a may be performed before step 801.

[0467] 800a, SMF1 sends a path state subscription request to the onboard UPF1, and in turn, the onboard UPF1 receives the path state subscription request from SMF1.

[0468] Optionally, the embodiment shown in Figure 8 further includes step 800b. Step 800b may be performed after step 800a.

[0469] 800b. The onboard UPF1 sends a path status notification message to the SMF1, and the corresponding SMF1 receives the path status notification message from the onboard UPF1.

[0470] Optionally, the embodiment shown in FIG8 further includes step 800c. Step 800c may be performed before step 801.

[0471] 800c and SMF2 send path state subscription requests to the onboard UPF2, and the onboard UPF2 receives the path state subscription requests from SMF2 accordingly.

[0472] Optionally, the embodiment shown in Figure 8 further includes step 800d. Step 800d may be performed after step 800c.

[0473] 800d, the onboard UPF2 sends a path status notification message to the SMF2, and the corresponding SMF2 receives the path status notification message from the onboard UPF2.

[0474] In this embodiment, steps 800a to 800d are similar to steps 500a to 500d in the embodiment shown in Figure 5 above, and will not be described in detail here.

[0475] Please refer to Figure 9, which is another schematic diagram of the communication method provided in this application embodiment. The method shown in Figure 9 is executed interactively by UE1, UE2, onboard AGW1, onboard AGW2, SMF1, SMF2, ground AGW1, ground AGW2, P-CSCF1, and P-CSCF2. The method shown in Figure 9 can be applied to the application scenario shown in Figure 4. Onboard UPF1 corresponds to the AGW on the first satellite, and onboard UPF2 corresponds to the AGW on the second satellite. SMF1, SMF2, ground AGW1, ground AGW2, P-CSCF1, and P-CSCF2 are all network devices deployed on the ground. Onboard AGW1 is the third network element, onboard AGW2 is the fourth network element, SMF2 is the first session management function network element, SMF1 is the second session management function network element, P-CSCF1 is the first proxy call session control function network element, P-CSCF2 is the second proxy call session control function network element, the ground access gateway is ground AGW1 or ground AGW2, and the second ground network is the IMS network. In this embodiment, UE1 is a third terminal device, UE2 is a fourth terminal device, SMF1 is responsible for managing the onboard UPF1, and SMF2 is responsible for managing the onboard UPF2. The method includes steps 901 to 910.

[0476] 901. P-CSCF1 obtains the identification information of the onboard AGW1.

[0477] P-CSCF1 receives a SIP Invite request from a third terminal device (UE1), which includes identification information for a fourth terminal device (UE2). This identification information can be the IP address of the fourth terminal device, or other information used to identify the fourth terminal device, such as MSISDN; specific details are not limited here. Based on the SIP Invite request from the third terminal device, P-CSCF1 determines the onboard AGW1, which is deployed on the same NTN device as the onboard access network device accessed by UE1.

[0478] 902. P-CSCF1 sends a call request to P-CSCF2, and P-CSCF2 receives the call request from P-CSCF1 accordingly.

[0479] The call request includes identification information for the onboard AGW1.

[0480] 903. P-CSCF2 obtains path status information.

[0481] If UE2 is also currently accessing via a regenerating satellite, then P-CSCF2 selects the onboard AGW2. P-CSCF2 obtains path status information based on the identification information of the onboard AGW1. This path status information is used to indicate the status of the onboard link between the third network element deployed on the first NTN device and the fourth network element deployed on the second NTN device. In this embodiment, the first NTN device is the first satellite shown in Figure 4, the third network element is the onboard AGW1, the second NTN device is the second satellite shown in Figure 4, and the fourth network element is AGW2. Therefore, this path status information is used to indicate the path status between onboard AGW1 and onboard AGW2.

[0482] Specifically, the path status information is used to indicate whether the inter-satellite link between satellite AGW1 and satellite AGW2 is reachable, the link latency of the inter-satellite link, and the link packet loss rate. For example, the path status information can be a path status value, meaning the status of the inter-satellite link between satellite AGW1 and satellite AGW2 can be represented by a specific numerical value. For instance, 1 bit can be used to represent whether the inter-satellite link is reachable; a path status value of 0 indicates that the inter-satellite link is unreachable, and a path status value of 1 indicates that the inter-satellite link is reachable. Another example is that the path status value can be the link latency or the link packet loss rate of the inter-satellite link; specific details are not limited here. The path status information can also be a set of multiple path status values, or the path status value can indicate whether the path status value is greater than or less than a preset threshold; specific details are not limited here. The path status information can also be a path availability indicator or a path unavailability indicator. The path availability indicator means that the inter-satellite link between satellite AGW1 and satellite AGW2 is available, and the path unavailability indicator means that the inter-satellite link between satellite AGW1 and satellite AGW2 is unavailable. The specific details are not limited here.

[0483] In one possible implementation, P-CSCF2 can send a path status subscription request indication to the onboard AGW2, and send a path status notification message to P-CSCF2 when entering P-CSCF2's service area. See steps 900c and 900d for details.

[0484] Based on the identification information of the onboard AGW1, P-CSCF2 determines the path status between onboard AGW2 and onboard AGW1 from the path status information between onboard AGW2 and multiple neighboring onboard AGWs contained in the path status notification message, thereby obtaining path status information. Specifically, when multiple neighboring onboard AGWs include onboard AGW1, P-CSCF2 can obtain the path status between onboard AGW2 and onboard AGW1 from the path status information between onboard AGW2 and multiple neighboring onboard AGWs; or, when multiple neighboring onboard AGWs do not include onboard AGW1, P-CSCF2 can determine that there is no available inter-satellite path between onboard AGW1 and onboard AGW2, i.e., the inter-satellite path status is unavailable.

[0485] In another possible implementation, P-CSCF2 sends a query request message to the onboard AGW2. This query request message includes the identification information of the onboard AGW1. This message instructs the onboard AGW2 to query the path status between the two onboard AGWs based on the identification information of the onboard AGW1. Upon receiving the query request message, the onboard AGW2 obtains the identification information of the onboard AGW1. If the onboard AGW2 has not configured the onboard AGW1 as a neighboring onboard AGW, it can be assumed that there is no inter-satellite path reachable between them. If the onboard AGW2 has configured the onboard AGW1 as a neighboring onboard AGW, then the onboard AGW2 obtains the path status information based on the monitoring results. In response to the query request message, the onboard AGW2 sends a first response message to P-CSCF2. If the inter-satellite path between the onboard AGW1 and the onboard AGW2 is reachable, the first response message includes path status information; if the inter-satellite path between the onboard AGW1 and the onboard AGW2 is unreachable, the first response message includes a path unavailability indication.

[0486] P-CSCF2 can first query the availability of the inter-satellite path between onboard AGW2 and onboard AGW1. If the inter-satellite path is available, P-CSCF2 can be configured. Alternatively, P-CSCF2 can directly configure onboard AGW2 and notify that the path is an inter-satellite path. Based on this instruction, onboard AGW2 determines the availability of the inter-satellite path between itself and onboard AGW1. If available, onboard AGW2 continues to complete the configuration; otherwise, it returns a failure and indicates that the inter-satellite path is unavailable.

[0487] 904. P-CSCF2 sends a call signaling message to UE2, and UE2 receives the call signaling message from P-CSCF2 accordingly.

[0488] P-CSCF2 sends a call signaling message to UE2. This call signaling message includes the IP address of the fourth network element, that is, the call signaling message includes the IP address of the onboard AGW2.

[0489] 905. P-CSCF2 sends third service flow information to SMF2, and correspondingly, SMF2 receives the third service flow information from P-CSCF2.

[0490] The third service flow information is used to indicate the service flow information between the fourth terminal device and the fourth network element, namely the service flow information between UE2 and the onboard AGW2. In response to the third service flow information, SMF2 executes step 906.

[0491] 906, SMF2 is configured with onboard UPF2.

[0492] SMF2 receives an instruction from P-CSCF2 and configures the onboard UPF2 accordingly to support the transmission of data received from the onboard AGW2 that needs to be sent to UE2 to the access network equipment on the second satellite, thereby sending it to UE2. Simultaneously, it sends data packets from UE2 to the onboard AGW2.

[0493] Alternatively, in another alternative implementation, SMF2 may also remove the onboard UPF2 from the call path, that is, instruct PSA2 to directly send the data packets received from the ground AGW2 and sent to UE2 to the onboard base station (i.e., the base station deployed on the same satellite as the onboard UPF2), and instruct the onboard base station to send the data packets received from UE2 and sent to the ground AGW2 to PSA2.

[0494] 907. P-CSCF2 sends a call response to P-CSCF1, and P-CSCF1 receives the call response from P-CSCF2 accordingly.

[0495] The call response is the response message corresponding to the call request in step 902. If this session supports inter-satellite links, the call response includes the identification information of the onboard AGW2 and the IP address of UE2. The call response also instructs P-CSCF1 to establish an inter-satellite path.

[0496] 908. P-CSCF1 sends a call signaling to UE1, and UE1 receives the call signaling from P-CSCF1 accordingly.

[0497] 909. P-CSCF1 sends the fourth service flow information to SMF1, and correspondingly, SMF1 receives the fourth service flow information from P-CSCF1.

[0498] The fourth service flow information is used to indicate the service flow information between the third terminal device and the third network element, that is, the service flow information between UE1 and the onboard AGW1. In response to the fourth service flow information, SMF1 executes step 910.

[0499] 910, SMF1 is equipped with a spaceborne UPF1.

[0500] Step 910 is similar to step 906 in this embodiment, and will not be described in detail here.

[0501] Optionally, the embodiment shown in FIG9 further includes step 900a. Step 900a may be performed before step 901.

[0502] In this embodiment, since the P-CSCF queries the inter-satellite path through the onboard AGW and then decides whether to enable UE-SAT-UE communication based on the reachability of the inter-satellite path, the P-CSCF does not need to query the external system to obtain the inter-satellite path status, thus avoiding the problem of not being able to query the reachability of the inter-satellite path due to the lack of standardization of the external interface.

[0503] 900a, P-CSCF1 sends a path state subscription request to the onboard AGW1, and in turn, the onboard AGW1 receives the path state subscription request from P-CSCF1.

[0504] When the onboard AGW1 enters the service area of ​​P-CSCF1, P-CSCF1 sends a path status subscription request to the onboard AGW1. This request is used to request the status of the inter-satellite paths between the onboard AGW1 and all configured neighboring onboard AGWs. This path status subscription request can also request a path status change report when the path status between the onboard AGW1 and neighboring onboard AGWs changes. For example, when the status of the inter-satellite path between the onboard AGW1 and any configured neighboring AGW changes from reachable to unreachable, or from unreachable to reachable, a path status change report is sent to P-CSCF1. As another example, P-CSCF1 can configure a preset threshold in the path status subscription request. When the link latency or link packet loss rate of the inter-satellite link between the onboard AGW and any configured neighboring onboard AGW changes from less than the preset threshold to greater than the preset threshold, or from greater than the preset threshold to less than the preset threshold, a path status change report and the latest path status information are sent to P-CSCF1.

[0505] Optionally, the embodiment shown in Figure 9 further includes step 900b. Step 900b may be performed after step 900a.

[0506] 900b. The onboard AGW1 sends a path status notification message to P-CSCF1, and P-CSCF1 receives the path status notification message from the onboard AGW1.

[0507] In response to the path status subscription request, the onboard AGW1 sends the path status notification message to P-CSCF1, carrying the status of the inter-satellite path between the onboard AGW1 and one or more of the configured neighboring onboard AGWs.

[0508] Optionally, the embodiment shown in Figure 9 further includes step 900c. Step 900c may be performed before step 901.

[0509] 900c and P-CSCF2 send path state subscription requests to the onboard AGW2, and the onboard AGW2 receives the path state subscription requests from P-CSCF2 accordingly.

[0510] Step 900c is similar to step 900a in this embodiment, and will not be described in detail here.

[0511] Optionally, the embodiment shown in Figure 9 further includes step 900d. Step 900d may be performed after step 900c.

[0512] 900d and the onboard AGW2 send path status notification messages to P-CSCF2, and P-CSCF2 receives path status notification messages from the onboard AGW2 accordingly.

[0513] Step 900d is similar to step 900b in this embodiment, and will not be described in detail here.

[0514] Optionally, the embodiment shown in FIG9 further includes step 907a. Step 907a may be performed after step 907.

[0515] 907a, P-CSCF1 obtain path status information;

[0516] Step 907a is similar to step 903 in this embodiment, and will not be described in detail here.

[0517] In practical applications, because the satellite is constantly moving, the path status between onboard AGW1 and onboard AGW2 may change. For example, the path status between onboard AGW1 and onboard AGW2 may change from an available state to an unavailable state. Or, for another example, the path status between onboard AGW1 and onboard AGW2 may change from an unavailable state to an available state.

[0518] The following example illustrates the change in path status between onboard AGW1 and onboard AGW2 from available to unavailable. Please refer to Figure 10, which is another schematic diagram of the communication method provided in this embodiment. The method shown in Figure 10 is executed interactively by onboard AGW1, onboard AGW2, SMF1, SMF2, P-CSCF1, and P-CSCF2. The method shown in Figure 10 can be applied to the application scenario shown in Figure 4. Onboard AGW1 corresponds to the AGW on the first satellite, and onboard AGW2 corresponds to the AGW on the second satellite. SMF1, SMF2, P-CSCF1, and P-CSCF2 are all network devices deployed on the ground. Onboard AGW1 is the third network element, onboard AGW2 is the fourth network element, SMF2 is the first session management function network element, SMF1 is the second session management function network element, P-CSCF1 is the first proxy call session control function network element, and P-CSCF2 is the second proxy call session control function. In this embodiment, UE1 is a third terminal device, UE2 is a fourth terminal device, SMF1 is responsible for managing the onboard UPF1, and SMF2 is responsible for managing the onboard UPF2. The method includes steps 1001 to 1011.

[0519] 1001. The onboard AGW1 sends a path status change report to P-CSCF1, and P-CSCF1 receives the path status change report from the onboard AGW1.

[0520] Based on step 900a in the embodiment shown in Figure 9, P-CSCF1 instructs the onboard AGW1 to send a path status change report when the path status between onboard AGW1 and onboard AGW2 changes, via a path status subscription request. In this embodiment, the path status change report is used to indicate that the path status between onboard AGW1 and onboard AGW2 has changed from an available state to an unavailable state.

[0521] 1002. P-CSCF1 Select and configure ground AGW1.

[0522] Step 1002 in this embodiment is similar to step 703 in the embodiment shown in Figure 7 above, and will not be described in detail here.

[0523] 1003. P-CSCF1 sends a path switching notification to P-CSCF2, and P-CSCF2 receives the path switching notification from P-CSCF1 accordingly.

[0524] P-CSCF1 sends a switching path notification to P-CSCF2 to instruct P-CSCF2 to switch the inter-satellite path to a terrestrial path. Specifically, this switching path notification may be a fourth piece of information or carried within a fourth piece of information. This switching path notification is used to indicate a switch from the first path to the second path, where the first path is the path from the third terminal device to the fourth terminal device via the third and fourth network elements, i.e., the path from UE1 to UE2 via onboard AGW1 and onboard AGW2; the second path is the path from the third terminal device to the fourth terminal device via the terrestrial access gateway, i.e., the path from UE1 to UE2 via terrestrial AGW1 and terrestrial AGW2.

[0525] 1004. P-CSCF1 sends a second indication message to UE1, and UE1 receives the second indication message from P-CSCF1 accordingly.

[0526] P-CSCF1 sends a second instruction message to UE1 to instruct UE1 to switch from the first path to the second path. The first path is the path from the third terminal device to the fourth terminal device through the third network element and the fourth network element, that is, the path from UE1 to UE2 through the satellite AGW1 and satellite AGW2. The second path is the path from the third terminal device to the fourth terminal device through the terrestrial access gateway, that is, the path from UE1 to UE2 through the terrestrial AGW1 and terrestrial AGW2.

[0527] Specifically, the second instruction information is used to instruct UE1 to change the destination address of the data packets sent to UE2 from the IP address of the spaceborne AGW1 to the IP address of the ground AGW1, thereby changing the transmission path of UE1 from the first path to the second path.

[0528] It should be noted that this embodiment does not limit the timing between steps 1003 and 1004. Step 1003 can be executed before or after step 1004; the specific execution time is not limited here. Step 1004 can be executed after receiving the response message from step 1003.

[0529] 1005. P-CSCF2 Select and configure ground AGW2.

[0530] Step 1005 in this embodiment is similar to step 706 in the embodiment shown in Figure 7 above, and will not be described in detail here.

[0531] 1006. P-CSCF2 sends a second indication message to UE2, and UE2 receives the second indication message from P-CSCF2 accordingly.

[0532] Step 1006 is similar to step 1004 in this embodiment, and will not be described in detail here.

[0533] 1007. P-CSCF2 sends a handover path response to P-CSCF1, and P-CSCF1 receives the handover path response from P-CSCF2 accordingly.

[0534] The path switching response is the response message of the path switching notification shown in step 1003. The path switching response carries the IP address of the ground access gateway, that is, the IP address of the ground AGW2.

[0535] 1008. P-CSCF2 sends the first service flow information to SMF2, and correspondingly, SMF2 receives the first service flow information from P-CSCF2.

[0536] The first service flow information is used to indicate the service flow information between the fourth terminal device and the ground access gateway, that is, the service flow information between UE2 and ground AGW2. In response to the first service flow information, SMF2 executes step 1009.

[0537] 1009, SMF2 is configured with a satellite-borne UPF2.

[0538] Step 1009 in this embodiment is similar to step 906 in the embodiment shown in Figure 9 above, and will not be described in detail here.

[0539] 1010. P-CSCF1 sends the second service flow information to SMF1, and correspondingly, SMF1 receives the second service flow information from P-CSCF1.

[0540] The second service flow information is used to indicate the service flow information between the third terminal device and the ground access gateway, that is, the service flow information between UE1 and ground AGW1. In response to the second service flow information, SMF1 executes step 1011.

[0541] 1011, SMF1 is configured with a spaceborne UPF1.

[0542] Step 1011 in this embodiment is similar to step 909 in the embodiment shown in Figure 9 above, and will not be described in detail here.

[0543] In this embodiment of the application, the continuity of call services is ensured and call service interruption is prevented by switching to a ground path when the inter-satellite path changes from available to unavailable.

[0544] It should be understood that the embodiment shown in Figure 10 takes the change of the path status between onboard AGW1 and onboard AGW2 from an available state to an unavailable state as an example. In practical applications, the path status between onboard AGW1 and onboard AGW2 can also change from an unavailable state to an available state. In this case, the second indication information in steps 1004 and 1006 of the embodiment shown in Figure 10 is used to instruct the third or fourth terminal device to switch from the second path to the first path. If the onboard AGW and onboard UPF retain the configuration information of the first path, then it is only necessary to notify the UE to perform a path switch; otherwise, steps 1009 and 1011 need to be re-executed.

[0545] Please refer to Figure 11, which is another schematic diagram of the communication method provided in this application embodiment. The method shown in Figure 11 is executed interactively by onboard AGW1, onboard AGW2, SMF1, SMF2, P-CSCF1, and P-CSCF2. The method shown in Figure 11 can be applied to the application scenario shown in Figure 4. Onboard AGW1 corresponds to the AGW on the first satellite, and onboard AGW2 corresponds to the AGW on the second satellite. SMF1, SMF2, P-CSCF1, and P-CSCF2 are all network devices deployed on the ground. Onboard AGW1 is the third network element, onboard AGW2 is the fourth network element, SMF2 is the first session management function network element, SMF1 is the second session management function network element, P-CSCF1 is the first proxy call session control function network element, and P-CSCF2 is the second proxy call session control function. In this application embodiment, UE1 is the third terminal device, UE2 is the fourth terminal device, SMF1 is responsible for managing onboard UPF1, and SMF2 is responsible for managing onboard UPF2. The method includes steps 1101 to 1113.

[0546] 1101. P-CSCF1 obtains the identification information of the onboard AGW1.

[0547] Step 1101 in this embodiment is similar to step 901 in the embodiment shown in Figure 9 above, and will not be described in detail here.

[0548] 1102. P-CSCF1 Select and configure ground AGW1.

[0549] Step 1102 in this embodiment is similar to step 703 in the embodiment shown in Figure 7 above, and will not be described in detail here.

[0550] 1103. P-CSCF1 sends a call request to P-CSCF2, and P-CSCF2 receives the call request from P-CSCF1 accordingly.

[0551] The call request included the IP address of the spaceborne AGW1 and the IP address of the ground-based AGW1.

[0552] 1104. P-CSCF2 Select and configure ground AGW2.

[0553] Step 1005 in this embodiment is similar to step 706 in the embodiment shown in Figure 7 above, and will not be described in detail here.

[0554] 1105. P-CSCF2 sends path configuration information to the onboard AGW2.

[0555] The path configuration information includes the IP address of the onboard AGW1 and the IP address of the ground AGW2. The IP address of the onboard AGW1 indicates the third path, and the IP address of the ground AGW2 indicates the fourth path. The third path is the path from the third terminal device to the fourth terminal device via the third and fourth network elements, i.e., the path from UE1 to UE2 via the onboard AGW1 and AGW2. The fourth path is the path from the third network element to the fourth network element via the ground access gateway, i.e., the path from the onboard AGW1 to the onboard AGW2 via the ground AGW1 and AGW2.

[0556] It should be understood that the third path and fourth path in the embodiments of this application are used to indicate the nodes through which the data packet passes, and do not limit the transmission direction. For example, in the third path, the data packet can travel from the third terminal device to the fourth terminal device through the third network element and the fourth network element, or it can travel from the fourth terminal device to the third terminal device through the fourth network element and the third network element; the specific direction is not limited here.

[0557] Optionally, P-CSCF2 may also send a fifth instruction message to the onboard AGW2, which instructs the onboard AGW2 to use the third or fourth path to transmit data based on the path status of the third and fourth paths.

[0558] Optionally, P-CSCF2 may also send a path selection strategy to the onboard AGW2. This strategy is used by the onboard AGW2 to select a path. The path selection strategy includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold. The initial path indication indicates the path initially used by the onboard AGW2, and the path priority indicates the preferred path between the third and fourth paths. For example, if P-CSCF2 receives an indication from SMF2 that the third path (i.e., the inter-satellite path) is available, P-CSCF2 may instruct the onboard AGW2 to initially use the third path in the call signaling. The path latency threshold and path packet loss rate threshold included in the path selection strategy are used to monitor path availability; that is, when the path latency and path packet loss rate are less than the path latency threshold and path packet loss rate threshold, respectively, it indicates that the path is available. When a path is available, the path is then selected based on the path priority. For example, assuming both the third and fourth paths are available, and the third path has a higher priority, the third path is selected. For example, suppose the path selection strategy indicates that the path with the lowest latency should be selected, and according to path monitoring, the fourth path has the lowest latency, then the fourth path should be selected.

[0559] Optionally, P-CSCF2 may also send a sixth instruction message to the onboard AGW2, which is used to instruct the onboard AGW2 to perform path monitoring on the third and / or fourth paths in order to obtain the path status of the third and / or fourth paths.

[0560] 1106. P-CSCF2 sends a call signaling message to UE2, and UE2 receives the call signaling message from P-CSCF2 accordingly.

[0561] The call signaling includes the IP address of the onboard AGW2. For UE2, UE2 needs to send the data packets destined for UE1 to the onboard AGW2 based on the IP address of the onboard AGW2, and the onboard AGW2 determines the transmission path of the data packets.

[0562] 1107. P-CSCF2 sends the third service flow information to SMF2, and SMF2 receives the third service flow information from P-CSCF2 accordingly.

[0563] 1108, SMF2 is configured with a satellite-borne UPF2.

[0564] Steps 1107 to 1108 in this embodiment are similar to steps 905 to 906 in the embodiment shown in Figure 9 above, and will not be described in detail here.

[0565] 1109. P-CSCF2 sends a call response to P-CSCF1, and P-CSCF1 receives the call response from P-CSCF2 accordingly.

[0566] The call response is the response message corresponding to the call request in step 1103. This response message carries information about the ground path and the inter-satellite path. The inter-satellite path information includes the IP address of the onboard AGW2. The ground path information includes the address of the ground AGW2. This message may also indicate that both the ground path and the inter-satellite path be established simultaneously.

[0567] 1110. P-CSCF1 sends path configuration information to the onboard AGW1.

[0568] 1111. P-CSCF1 sends a call signaling to UE1, and UE1 receives the call signaling from P-CSCF1 accordingly.

[0569] 1112. P-CSCF1 sends the fourth service flow information to SMF1, and SMF1 receives the fourth service flow information from P-CSCF1 accordingly.

[0570] 1113. SMF1 is configured with a spaceborne UPF1.

[0571] Steps 1112 to 1113 in this embodiment are similar to steps 909 to 910 in the embodiment shown in Figure 9 above, and will not be described in detail here.

[0572] Optionally, the embodiment shown in FIG11 further includes step 1100a. Step 1100a may be performed before step 1101.

[0573] 1100a. P-CSCF1 sends a path state subscription request to the onboard AGW1, and in turn, the onboard AGW1 receives the path state subscription request from P-CSCF1.

[0574] Optionally, the embodiment shown in FIG11 further includes step 1100b. Step 1100b may be performed after step 1100a.

[0575] 1100b. The onboard AGW1 sends a path status notification message to the P-CSCF1, and the P-CSCF1 receives the path status notification message from the onboard AGW1.

[0576] Optionally, the embodiment shown in FIG11 further includes step 1100c. Step 1100c may be performed before step 1101.

[0577] 1100c, P-CSCF2 sends a path state subscription request to the onboard AGW2, and the onboard AGW2 receives the path state subscription request from P-CSCF2 accordingly.

[0578] Optionally, the embodiment shown in FIG11 further includes step 1100d. Step 1100d may be performed after step 1100c.

[0579] 1100d, the onboard AGW2 sends a path status notification message to P-CSCF2, and P-CSCF2 receives the path status notification message from the onboard AGW2 accordingly.

[0580] Steps 1100a to 1100d in this embodiment are similar to steps 900a to 900d in the embodiment of Figure 9 above, and will not be described in detail here.

[0581] The communication method in the embodiments of this application has been described above. The communication device in the embodiments of this application is described below. Referring to Figure 12, the communication device 1200 can be used to execute the process of the session management network element (SMF1 or SMF2) in the embodiments shown in Figures 5 to 11. For details, please refer to the relevant descriptions in the foregoing method embodiments. The communication device 1200 can be a network device, a component or device applied to a network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of a network device.

[0582] The communication device 1200 includes an interface module 1201 and a processing module 1202.

[0583] The processing module 1202 is used for data processing. The interface module 1201 can implement corresponding communication functions. The interface module 1201 can also be called a communication interface or a communication module.

[0584] Optionally, the communication device 1200 may further include a storage module, which can be used to store program code, program instructions and / or data. The processing module 1202 can read the instructions and / or data in the storage module so that the communication device 1200 can implement the aforementioned method embodiments.

[0585] The communication device 1200 can be used to perform the actions performed by the session management network element in the above method embodiments. For example, it can be a session management network element, a communication module within a session management network element, or a circuit or chip within a session management network element responsible for communication functions. The communication device 1200 can be a session management network element or a component configurable within a session management network element. The processing module 1202 is used to perform processing-related operations on the session management network element side in the above method embodiments. The interface module 1201 is used to perform reception-related operations on the session management network element side in the above method embodiments.

[0586] Optionally, the interface module 1201 may include a sending module and a receiving module. The sending module is used to perform the sending operation in the above method embodiments. The receiving module is used to perform the receiving operation in the above method embodiments.

[0587] It should be noted that the communication device 1200 may include a transmitting module but not a receiving module. Alternatively, the communication device 1200 may include a receiving module but not a transmitting module. Specifically, it depends on whether the above-described scheme executed by the communication device 1200 includes both transmitting and receiving actions. For example, the communication device 1200 is used to execute the actions performed by the session management network element in the embodiments shown in Figures 5 to 11. For details, please refer to the relevant descriptions in the embodiments shown in Figures 5 to 11; these will not be elaborated upon here.

[0588] For example, the communication device 1200 is used to execute the following scheme:

[0589] Interface module 1201 is used to receive a first request message, the first request message including the identification information of a first network element, the first network element being deployed on a first non-terrestrial network device;

[0590] The processing module 1202 is used to obtain path status information based on the identification information of the first network element. The path status information is used to indicate the path status between the first network element and the second network element. The second network element is deployed on the second non-terrestrial network device. Both the first network element and the second network element are user plane function network elements.

[0591] In one possible implementation, the interface module 1201 is also used to receive a path status notification message, which includes the path status between the second network element and multiple network elements.

[0592] The processing module 1202 is specifically used to determine the path status information based on the identification information of the first network element and the path status notification message.

[0593] In another possible implementation, the interface module 1201 is also used to send a query request message, which includes the identification information of the first network element. The identification information of the first network element is used to obtain the path status between the first network element and the second network element.

[0594] Interface module 1201 is also used to receive a first response message, which is a response message to the query request message and is used to indicate path status information.

[0595] In another possible implementation, the interface module 1201 is further configured to send a second response message, which is a response message to the first request message; wherein, if the path status information indicates that the path status between the first network element and the second network element is available, the second response message includes the tunnel information of the second network element.

[0596] Alternatively, if the path status information indicates that the path status between the first network element and the second network element is unavailable, then the second response message includes a path unavailable indication.

[0597] In another possible implementation, the first request message also includes the tunnel information of the first network element and the Internet Protocol IP address of the first terminal device. The interface module 1201 is also used to send a first traffic splitting rule, which instructs the second network element to send the first data packet to the first network element according to the tunnel information of the first network element. The destination address of the first data packet is the IP address of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services to the first terminal device, and the second network element provides services to the second terminal device.

[0598] In another possible implementation, the interface module 1201 is specifically used to send the first traffic splitting rule when the path status information indicates that the path status between the first network element and the second network element is available.

[0599] In another possible implementation, interface module 1201 is also used to send a second traffic splitting rule, which instructs the second network element to send the first data packet to the session anchor point. The destination address of the first data packet is the IP address of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services to the first terminal device, and the second network element provides services to the second terminal device. The session anchor point is deployed on the first terrestrial network.

[0600] In another possible implementation, the interface module 1201 is specifically used to send a second traffic splitting rule when the path status information indicates that the path status between the first network element and the second network element is unavailable.

[0601] In another possible implementation, the interface module 1201 is also used to send first indication information, which is used to instruct the second network element to use the first diversion rule or the second diversion rule according to the path status information.

[0602] In another possible implementation, the interface module 1201 is specifically used to send first indication information when sending the first diversion rule and the second diversion rule.

[0603] In another possible implementation, the interface module 1201 is also used to receive first information, which is used to indicate that the path status between the first network element and the second network element has changed, or to indicate the switching of the transmission path between the first network element and the second network element.

[0604] Interface module 1201 is specifically used to send the first diversion rule according to the first information;

[0605] The interface module 1201 is specifically used to send the second diversion rule according to the first information.

[0606] In another possible implementation, the interface module 1201 is also used to receive second information, which includes service flow information between the second terminal device and the ground access gateway. The ground access gateway is deployed in the second ground network, and the ground access gateway and the second network element transmit data through a session anchor point.

[0607] The interface module 1201 is specifically used to respond to the second information by sending a third traffic splitting rule and a fourth traffic splitting rule. The third traffic splitting rule is used to instruct the second network element to send a third data packet to the session anchor point. The third data packet is a data packet sent by the second terminal device to the ground access gateway. The fourth traffic splitting rule is used to instruct the second network element to send a fourth data packet from the session anchor point to the second terminal device. The fourth data packet is a data packet sent by the ground access gateway to the second terminal device.

[0608] In another possible implementation, the interface module 1201 is also used to receive third information, which is used to indicate that the path status between the first network element and the second network element has changed;

[0609] If, according to the third information, the path status between the first network element and the second network element changes from unavailable to available, then in response to the third information, a path availability indication is sent.

[0610] Alternatively, if the path status between the first network element and the second network element changes from available to unavailable according to the third information, then in response to the third information, a path unavailable indication is sent.

[0611] In another possible implementation, the first request message also includes the IP address of the second terminal device and the IP address of the terrestrial access gateway. The interface module 1201 is also used to send a third traffic splitting rule, which instructs the second network element to send a third data packet from the session anchor to the second terminal device. The third data packet is a data packet sent by the terrestrial access gateway to the second terminal device. The terrestrial access gateway is deployed in the second terrestrial network, and the session anchor is deployed in the first terrestrial network. The terrestrial access gateway and the second network element transmit the third data packet through the session anchor.

[0612] It should be understood that the specific procedures for each module to perform the above-mentioned corresponding processes have been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0613] The processing module 1202 in the above embodiments can be implemented by at least one processor or processor-related circuitry. The interface module 1201 can be implemented by a transceiver or transceiver-related circuitry. The interface module 1201 can also be referred to as a communication module or communication interface. The storage module can be implemented by at least one memory.

[0614] The following is another structural schematic diagram of the communication device according to an embodiment of this application. Referring to FIG13, the communication device can be used to execute the process of the first proxy call session control function network element (P-CSCF1) in the embodiments shown in FIG5 to FIG11. For details, please refer to the relevant description in the foregoing method embodiments.

[0615] The communication device 1300 includes an interface module 1301. Optionally, a processing module 1302.

[0616] The processing module 1302 is used for data processing. The interface module 1301 can implement corresponding communication functions. The interface module 1301 can also be called a communication interface or a communication module.

[0617] Optionally, the communication device 1300 may further include a storage module, which can be used to store program code, program instructions and / or data. The processing module 1302 can read the instructions and / or data in the storage module so that the communication device 1300 can implement the aforementioned method embodiments.

[0618] The communication device 1300 can be used to perform the actions performed by the first proxy call session control function network element in the above method embodiment. For example, it can be the first proxy call session control function network element, its communication module, or a circuit or chip responsible for communication functions within the first proxy call session control function network element. The communication device 1300 can be the first proxy call session control function network element or a component configurable within it. The processing module 1302 is used to perform processing-related operations on the first proxy call session control function network element side in the above method embodiment. The interface module 1301 is used to perform reception-related operations on the first proxy call session control function network element side in the above method embodiment.

[0619] Optionally, interface module 1301 may include a sending module and a receiving module. The sending module is used to perform the sending operation in the above method embodiments. The receiving module is used to perform the receiving operation in the above method embodiments.

[0620] It should be noted that the communication device 1300 may include a transmitting module but not a receiving module. Alternatively, the communication device 1300 may include a receiving module but not a transmitting module. Specifically, it depends on whether the above-described scheme executed by the communication device 1300 includes both transmitting and receiving actions. For example, the communication device 1300 is used to execute the actions performed by the first proxy call session control function network element in the embodiments shown in Figures 5 to 11. For details, please refer to the relevant descriptions in the embodiments shown in Figures 5 to 11; they will not be elaborated upon here.

[0621] For example, the communication device 1300 is used to execute the following scheme:

[0622] The processing module 1302 is used to obtain the identification information of the third network element, which is deployed on the first non-terrestrial network device;

[0623] Interface module 1301 is used to send the identification information of the third network element. The identification information of the third network element is used to obtain the transmission path between the third terminal device and the fourth terminal device. The third network element provides services to the third terminal device.

[0624] The interface module 1301 is also used to receive a third response message, which is used to indicate the transmission path between the third terminal device and the fourth terminal device. The third network element is a user plane function network element or an access gateway.

[0625] In one possible implementation, interface module 1301 is further configured to send a third request message, the third request message including the identification information of a third terminal device;

[0626] The interface module 1301 is also used to receive a fourth response message, which is a response message to the third request message and includes the identification information of the third network element.

[0627] In another possible implementation, the third response message includes indication information for the first path and / or indication information for the second path. The first path is the path from the third terminal device to the fourth terminal device via the third network element and the fourth network element. The second path is the path from the third terminal device to the fourth terminal device via a session anchor or a terrestrial access gateway. The fourth network element provides services to the fourth terminal device. The session anchor is deployed in the first terrestrial network, and the terrestrial access gateway is deployed in the second terrestrial network. The session anchor includes a session anchor that provides services to the third terminal device and a session anchor that provides services to the fourth terminal device. The terrestrial access gateway includes a terrestrial access gateway that provides services to the third terminal device and a terrestrial access gateway that provides services to the fourth terminal device.

[0628] In another possible implementation, when the fourth network element is a user plane function network element, the indication information of the first path includes the tunnel information of the fourth network element and the IP address of the fourth terminal device; or, when the fourth network element is an access gateway, the indication information of the first path includes the IP address of the fourth network element; when the second path is a path between the third terminal device and the fourth terminal device through a terrestrial access network element, the indication information of the second path includes the IP address of the terrestrial access gateway; or, when the second path is a path between the third terminal device and the third terminal device through a session anchor point, the indication information of the second path includes the IP address of the fourth terminal device.

[0629] In another possible implementation, interface module 1301 is also used to send call signaling, which is used to indicate a first path and / or a second path.

[0630] The call signaling includes any one of the following: the IP address of the fourth terminal device, the IP address of the terrestrial access gateway, wherein the terrestrial access gateway is the terrestrial access gateway that provides services to the third terminal device, and the IP address of the third network element.

[0631] Scenario A: When the third response message indicates the first path and the third network element is a user plane function network element, the call signaling includes the IP address of the fourth terminal device. In this case, the third terminal device directly sends the session data packet to the fourth terminal device using the fourth terminal device's IP address.

[0632] Scenario B: When the fourth response message indicates the first path and the third network element is an access gateway, the call signaling includes the IP address of the third network element. In this case, the third terminal device first sends the session data packet destined for the fourth terminal device to the third network element, and then the third network element sends the session data packet to the fourth terminal device.

[0633] Scenario C: When the fourth response message indicates the second path, and the second path is the path between the third terminal device and the fourth terminal device through the session anchor, the call signaling includes the IP address of the fourth terminal device. In this case, the third terminal device sends session data packets directly to the fourth terminal device using the fourth terminal device's IP address.

[0634] Scenario D: When the fourth response message indicates the second path, and the second path is the path between the third terminal device and the fourth terminal device via a terrestrial access gateway, the call signaling includes the IP address of the terrestrial access gateway, which is the terrestrial access gateway providing services to the third terminal device. In this case, the third terminal device first sends the session data packets intended for the fourth terminal device to the terrestrial access gateway serving the third terminal device, and then the terrestrial access gateway forwards the session data packets to the fourth terminal device.

[0635] When the fourth response message simultaneously indicates the first path and the second path, the call signaling includes the information included in situation A or situation B and the information corresponding to situation C or situation D, respectively.

[0636] In another possible implementation, the interface module 1301 is also used to receive third information, which is used to indicate that the path status of the first path or the second path has changed;

[0637] The interface module 1301 is also used to send a fourth message, which is used to indicate whether to switch the first path to the second path or to indicate whether to switch the second path to the first path.

[0638] In another possible implementation, when the fourth information is used to indicate switching the first path to the second path, and the second path is the path between the third terminal device and the fourth terminal device through the terrestrial access gateway, the fourth information includes the IP address of the terrestrial access gateway, which is a terrestrial access gateway that provides services to the third terminal device and is deployed in the second terrestrial network.

[0639] Alternatively, when the fourth information is used to indicate switching the first path to the second path, and the second path is the path between the third terminal device and the fourth terminal device through the session anchor, the fourth information includes the IP address of the third terminal device.

[0640] Alternatively, when the fourth information indicates that the second path is switched to the first path and the third network element is a user plane function network element, the fourth information includes the tunnel information of the third network element and the IP address of the third terminal device, and the third network element provides services to the third terminal device.

[0641] Alternatively, when the fourth information indicates that the second path should be switched to the first path and both the third and fourth network elements are access gateways, the fourth information includes the IP address of the third network element.

[0642] In another possible implementation, the interface module 1301 is also used to send second indication information, which includes address information required by the third terminal device to send session data to the fourth terminal device through a target path, where the target path is either the first path or the second path.

[0643] In the case where the target path is as described in scenario A above, the second instruction information is used to instruct the third terminal device to send the session data packet directly to the fourth terminal device through the IP address of the fourth terminal device.

[0644] When the target path is case B above, the second instruction information is used to instruct the third terminal device to send the session data packet destined for the fourth terminal device to the third network element first, and then the third network element sends the session data packet to the fourth terminal device.

[0645] When the target path is case C as described above, the second instruction information is used to instruct the third terminal device to send the session data packet directly to the fourth terminal device through the IP address of the fourth terminal device.

[0646] When the target path is case D as described above, the second indication information is used to instruct the third terminal device to first send the session data packets destined for the fourth terminal device to the ground access gateway serving the third terminal device, and then the ground access gateway will send the session data packets to the fourth terminal device.

[0647] In another possible implementation, the interface module 1301 is also used to send fifth information during the path switching process. The fifth information includes service flow information between the third terminal device and the ground access gateway.

[0648] In another possible implementation, the call signaling also includes third indication information, which is used to instruct the third terminal device to transmit data using the first path or the second path according to the path status of the first path and / or the second path.

[0649] In another possible implementation, the call signaling also includes a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0650] In another possible implementation, the call signaling also includes a fourth indication information, which is used to instruct the third terminal device to perform path monitoring to obtain the path status of the first path and / or the second path.

[0651] In another possible implementation, the third network element is an access gateway, and the third response message includes information about the third path and / or the fourth path. The information about the third path includes the IP address of the fourth network element. The fourth network element is deployed on the second non-terrestrial network device. The fourth network element is an access gateway that provides services to the fourth terminal device. The information about the fourth path includes the IP address of the terrestrial access gateway, which is deployed on the second terrestrial network. The third path is the path from the third terminal device to the fourth terminal device through the third network element and the fourth network element. The fourth path is the path from the third terminal device to the fourth terminal device through the third network element and the terrestrial access gateway.

[0652] In another possible implementation, the interface module 1301 is also used to send a fifth indication message, which is used to instruct the third network element to use the third path or the fourth path to transmit data according to the path status of the third path and / or the fourth path.

[0653] In another possible implementation, interface module 1301 is also used to send a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0654] The interface module 1301 is also used to send a sixth indication message, which is used to instruct the third network element to monitor the path status of the third path and / or the fourth path.

[0655] In another possible implementation, when both the third network element and the fourth network element are access gateways, the third response message includes path status information. The processing module 1302 is also used to determine the transmission path based on the path status information. The path status information is determined based on the identification information of the third network element. The path status information is used to indicate the path status between the third network element and the fourth network element. The fourth network element provides services to the fourth terminal device.

[0656] It should be understood that the specific procedures for each module to perform the above-mentioned corresponding processes have been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0657] The processing module 1302 in the above embodiments can be implemented by at least one processor or processor-related circuitry. The interface module 1301 can be implemented by a transceiver or transceiver-related circuitry. The interface module 1301 can also be referred to as a communication module or communication interface. The storage module can be implemented by at least one memory.

[0658] The following is another structural schematic diagram of the communication device according to an embodiment of this application. Referring to Figure 14, the communication device can be used to execute the process of the second proxy call session control function network element (P-CSCF2) in the embodiments shown in Figures 5 to 11. For details, please refer to the relevant description in the foregoing method embodiments.

[0659] The communication device 1400 includes an interface module 1401. Optionally, a processing module 1402.

[0660] The processing module 1402 is used for data processing. The interface module 1401 can implement corresponding communication functions. The interface module 1401 can also be called a communication interface or a communication module.

[0661] Optionally, the communication device 1400 may further include a storage module, which can be used to store program code, program instructions and / or data. The processing module 1402 can read the instructions and / or data in the storage module so that the communication device 1400 can implement the aforementioned method embodiments.

[0662] The communication device 1400 can be used to perform the actions performed by the second proxy call session control function network element in the above method embodiment. For example, it can be the second proxy call session control function network element, its communication module, or a circuit or chip responsible for communication functions within the second proxy call session control function network element. The communication device 1400 can be the second proxy call session control function network element or a component configurable within it. The processing module 1402 is used to perform processing-related operations on the second proxy call session control function network element side in the above method embodiment. The interface module 1401 is used to perform reception-related operations on the second proxy call session control function network element side in the above method embodiment.

[0663] Optionally, interface module 1401 may include a sending module and a receiving module. The sending module is used to perform the sending operation in the above method embodiments. The receiving module is used to perform the receiving operation in the above method embodiments.

[0664] It should be noted that the communication device 1400 may include a transmitting module but not a receiving module. Alternatively, the communication device 1400 may include a receiving module but not a transmitting module. Specifically, it depends on whether the above-described scheme executed by the communication device 1400 includes both transmitting and receiving actions. For example, the communication device 1400 is used to execute the actions performed by the second proxy call session control function network element in the embodiments shown in Figures 5 to 11. For details, please refer to the relevant descriptions in the embodiments shown in Figures 5 to 11; they will not be elaborated upon here.

[0665] For example, the communication device 1400 is used to execute the following scheme:

[0666] Interface module 1401 is used to receive the identification information of the third network element. The identification information of the third network element is used to obtain the transmission path between the third terminal device and the fourth terminal device. The third network element provides services to the third terminal device. The third network element is a user plane function network element or an access gateway. The third network element is deployed on the first non-terrestrial network device.

[0667] Processing module 1402 is used to generate a third response message;

[0668] The interface module 1401 is also used to send a third response message, which is used to indicate the transmission path between the third terminal device and the fourth terminal device.

[0669] In one possible implementation, interface module 1401 is further configured to send a second request message, the second request message including the identification information of a third network device;

[0670] Interface module 1401 is also used to receive a fourth response message, which is a response message to the second request message. The fourth response message is used to indicate the path establishment status between the third network element and the fourth network element. The fourth network element provides services to the fourth terminal device. The fourth network element is deployed on the second non-terrestrial network device.

[0671] The processing module 1402 is also used to determine the transmission path between the third terminal device and the fourth terminal device based on the path establishment status between the third network element and the network element.

[0672] In another possible implementation, the third response message includes indication information for the first path or the second path. The first path is the path from the third terminal device to the fourth terminal device through the third network element and the fourth network element. The second path is the path from the third terminal device to the fourth terminal device through the session anchor or the terrestrial access gateway. The fourth network element provides services to the fourth terminal device. The session anchor is deployed in the first terrestrial network, and the terrestrial access gateway is deployed in the second terrestrial network.

[0673] In another possible implementation, if the path establishment status between the third network element and the fourth network element is successful, then the third response message includes indication information of the first path.

[0674] Alternatively, if the path establishment status between the third network element and the fourth network element is in the establishment failure status, the second response message includes indication information of the second path.

[0675] In another possible implementation, when the third network element is a user plane function network element, the indication information of the first path includes the tunnel information of the third network element and the IP address of the third terminal device; or, when the third network element is an access gateway, the indication information of the first path includes the IP address of the third network element; the indication information of the second path includes the IP address of the terrestrial access gateway.

[0676] In another possible implementation, interface module 1401 is also used to send call signaling, which includes the IP address of the third terminal device and / or the IP address of the terrestrial access gateway; or, when the fourth network element is an access gateway, the call signaling includes the IP address of the fourth network element and / or the IP address of the terrestrial access gateway.

[0677] In another possible implementation, the interface module 1401 is also used to receive third information, which indicates that the path status of the first path or the second path has changed.

[0678] The interface module 1401 is also used to send a fourth message, which is used to indicate whether to switch the first path to the second path or to indicate whether to switch the second path to the first path.

[0679] In another possible implementation, when the fourth information is used to indicate switching the first path to the second path, the fourth information includes the IP address of the ground access gateway, which is deployed in the second ground network;

[0680] Alternatively, when the fourth information indicates that the second path is switched to the first path and both the third and fourth network elements are user plane function network elements, the fourth information includes the tunnel information of the third network element and the IP address of the third terminal device, and the third network element provides services to the third terminal device.

[0681] Alternatively, when the fourth information indicates that the second path should be switched to the first path and both the third and fourth network elements are access gateways, the fourth information includes the IP address of the fourth network element.

[0682] In another possible implementation, the interface module 1401 is also used to send a second instruction message, which is used to instruct the fourth terminal device to switch the first path to the second path or the second path to the first path.

[0683] In another possible implementation, the interface module 1401 is also used to send fifth information, which includes service flow information between the fourth terminal device and the ground access gateway.

[0684] In another possible implementation, the call signaling also includes third indication information, which is used to instruct the fourth terminal device to transmit data using the first path or the second path according to the path status of the first path and / or the second path.

[0685] In another possible implementation, the call signaling also includes a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0686] In another possible implementation, the call signaling also includes fourth indication information, which is used to instruct the fourth terminal device to perform path monitoring to obtain the path status of the first path and / or the second path.

[0687] In another possible implementation, the fourth network element is an access gateway, and the third response message includes information about the third path and / or the fourth path. The information about the third path includes the IP address of the third network element, which is deployed on the second non-terrestrial network device. The third network element is an access gateway, and the information about the fourth path includes the IP address of the terrestrial access gateway, which is deployed on the second terrestrial network. The third path is the path between the third network element and the fourth network element, and the fourth path is the path between the fourth network element and the terrestrial access gateway.

[0688] In another possible implementation, the interface module 1401 is also used to send a fifth indication message, which is used to instruct the fourth network element to use the third path or the fourth path to transmit data according to the path status of the third path and / or the fourth path.

[0689] In another possible implementation, interface module 1401 is also used to send a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0690] The interface module 1401 is also used to send a sixth indication message, which is used to instruct the fourth network element to monitor the path status of the third path and / or the fourth path.

[0691] In another possible implementation, the processing module 1402 is also used to determine the transmission path based on the path status information. The path status information is determined based on the identification information of the third network element. The path status information is used to indicate the path status between the third network element and the fourth network element, and the fourth network element provides services to the fourth terminal device.

[0692] It should be understood that the specific procedures for each module to perform the above-mentioned corresponding processes have been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0693] The processing module 1402 in the above embodiments can be implemented by at least one processor or processor-related circuitry. The interface module 1401 can be implemented by a transceiver or transceiver-related circuitry. The interface module 1401 can also be referred to as a communication module or communication interface. The storage module can be implemented by at least one memory.

[0694] The following is another structural schematic diagram of the communication device according to an embodiment of this application. Referring to Figure 15, the communication device can be used to execute the process performed by the first network element, the second network element, the third network element, or the fourth network element (spaceborne UPF or spaceborne AGW) in the embodiments shown in Figures 5 to 11. For details, please refer to the relevant descriptions in the foregoing method embodiments.

[0695] The communication device 1500 includes an interface module 1501. Optionally, a processing module 1502.

[0696] The processing module 1502 is used for data processing. The interface module 1501 can implement corresponding communication functions. The interface module 1501 can also be called a communication interface or a communication module.

[0697] Optionally, the communication device 1500 may further include a storage module, which can be used to store program code, program instructions and / or data. The processing module 1502 can read the instructions and / or data in the storage module so that the communication device 1500 can implement the aforementioned method embodiments.

[0698] The communication device 1500 can be used to perform the actions performed by the spaceborne UPF or spaceborne AGW in the above method embodiments. For example, it can be a communication module within the spaceborne UPF or spaceborne AGW, or a circuit or chip within the spaceborne UPF or spaceborne AGW responsible for communication functions. The communication device 1500 can be a spaceborne UPF or spaceborne AGW, or a component configurable within the spaceborne UPF or spaceborne AGW. The processing module 1502 is used to perform processing-related operations on the spaceborne UPF or spaceborne AGW side in the above method embodiments. The interface module 1501 is used to perform reception-related operations on the spaceborne UPF or spaceborne AGW side in the above method embodiments.

[0699] Optionally, the interface module 1501 may include a sending module and a receiving module. The sending module is used to perform the sending operation in the above method embodiments. The receiving module is used to perform the receiving operation in the above method embodiments.

[0700] It should be noted that the communication device 1500 may include a transmitting module but not a receiving module. Alternatively, the communication device 1500 may include a receiving module but not a transmitting module. Specifically, it depends on whether the above-described scheme performed by the communication device 1500 includes both transmitting and receiving actions. For example, the communication device 1500 is used to perform the actions performed by the spaceborne UPF or spaceborne AGW in the embodiments shown in Figures 5 to 11. For details, please refer to the relevant descriptions in the embodiments shown in Figures 5 to 11; they will not be elaborated upon here.

[0701] For example, the communication device 1500 is used to execute the following scheme:

[0702] Processing module 1502 is used to determine path status information. The path status information is used to indicate the path status between the third network element and the fourth network element. The third network element is deployed on the first non-terrestrial network device, and the fourth network element is deployed on the second non-terrestrial network device. Both the third network element and the fourth network element are user plane function network elements, or both the third network element and the fourth network element are access gateways.

[0703] Interface module 1501 is used to transmit path status information;

[0704] The processing module 1502 is also used to determine the transmission path between the third terminal device and the fourth terminal device based on the path status information, wherein the first network element provides services to the first terminal device and the second network element provides services to the second terminal device.

[0705] In one possible implementation, the transmission path includes: a first path and / or a second path, wherein the first path is the path from the third terminal device to the fourth terminal device via a third network element and a fourth network element, and the second path is the path from the third terminal device to the fourth terminal device via a session anchor or a terrestrial access gateway, wherein the session anchor is deployed in a first terrestrial network, or the terrestrial access gateway is deployed in a second terrestrial network.

[0706] In another possible implementation, when the second path is the path between the third terminal device and the fourth terminal device through the session anchor, the interface module 1501 is also used to receive a first routing rule and / or a second routing rule, wherein the first routing rule is used to indicate the first path and the second routing rule is used to indicate the second path.

[0707] In another possible implementation, the interface module 1501 is also used to receive first indication information, which is used to indicate whether to use a first diversion rule or a second diversion rule based on the path status information.

[0708] The processing module 1502 is also configured to, in response to the first indication information, determine the transmission path of the first data packet using a first diversion rule or a second diversion rule based on the path status information.

[0709] In another possible implementation, the processing module 1502 is specifically used to determine the transmission path as the first path if the path status of the first path is available.

[0710] Alternatively, if the path status of the first path is unavailable, then the transmission path is determined to be the second path.

[0711] In another possible implementation, when the third network element and the fourth network element are access gateways, the transmission path includes: a third path and / or a fourth path, where the third path is the path between the third network element and the fourth network element, and the fourth path is the path between the third network element and the fourth network element through the terrestrial access gateway, which is deployed in the second terrestrial network.

[0712] In another possible implementation, when the second path is the path between the third terminal device and the fourth terminal device through the terrestrial access gateway, the interface module 1501 is also used to receive a path configuration message. The path configuration message includes the IP address of the third network element and / or the IP address of the terrestrial access gateway. The IP address of the third network element is used to indicate the first path or the third path, and the IP address of the terrestrial access gateway is used to indicate the second path or the fourth path.

[0713] In another possible implementation, the interface module 1501 is also used to receive fifth indication information, which instructs the third network element to use the third path or the fourth path to transmit data according to the path status of the third path and / or the fourth path.

[0714] In another possible implementation, interface module 1501 is also used to receive a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0715] In another possible implementation, the interface module 1501 is specifically used to receive a path state subscription request. The path state subscription request is used to request that a path state notification message be sent when the path state between the fourth network element and any one of the at least one network element changes.

[0716] The interface module 1501 is specifically used to send a path status notification message, which is used to indicate the path status between the fourth network element and any network device in at least one network element. The path status notification message includes path status information.

[0717] In another possible implementation, the interface module 1501 is also used to receive a query request message, which includes the identification information of the third network element and is used to request a query on the path status between the third network element and the fourth network element.

[0718] Interface module 1501 is also used to send a first response message, which is a response message to the query request message and is used to indicate path status information.

[0719] In another possible implementation, the interface module 1501 is also used to send first information, which indicates that the path status between the first network element and the second network element has changed.

[0720] It should be understood that the specific procedures for each module to perform the above-mentioned corresponding processes have been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0721] The processing module 1502 in the above embodiments can be implemented by at least one processor or processor-related circuitry. The interface module 1501 can be implemented by a transceiver or transceiver-related circuitry. The interface module 1501 can also be referred to as a communication module or communication interface. The storage module can be implemented by at least one memory.

[0722] The following is another structural schematic diagram of the communication device according to an embodiment of this application. Referring to Figure 16, the communication device can be used to execute the process performed by the terminal device (UE1 or UE2) in the embodiments shown in Figures 5 to 11. For details, please refer to the relevant description in the foregoing method embodiments.

[0723] The communication device 1600 includes an interface module 1601. Optionally, a processing module 1602.

[0724] The processing module 1602 is used for data processing. The interface module 1601 can implement corresponding communication functions. The interface module 1601 can also be called a communication interface or a communication module.

[0725] Optionally, the communication device 1600 may further include a storage module, which can be used to store program code, program instructions and / or data. The processing module 1602 can read the instructions and / or data in the storage module so that the communication device 1600 can implement the aforementioned method embodiments.

[0726] The communication device 1600 can be used to perform the actions performed by the terminal device in the above method embodiments. For example, it can be a terminal device, a communication module within a terminal device, or a circuit or chip within a terminal device responsible for communication functions. The communication device 1600 can be a terminal device or a component configurable on a terminal device. The processing module 1602 is used to perform processing-related operations on the terminal device side in the above method embodiments. The interface module 1601 is used to perform reception-related operations on the terminal device side in the above method embodiments.

[0727] Optionally, interface module 1601 may include a sending module and a receiving module. The sending module is used to perform the sending operation in the above method embodiments. The receiving module is used to perform the receiving operation in the above method embodiments.

[0728] It should be noted that the communication device 1600 may include a transmitting module but not a receiving module. Alternatively, the communication device 1600 may include a receiving module but not a transmitting module. Specifically, it depends on whether the above-described scheme performed by the communication device 1600 includes both transmitting and receiving actions. For example, the communication device 1600 is used to perform the actions performed by the terminal device in the embodiments shown in Figures 5 to 11. For details, please refer to the relevant descriptions in the embodiments shown in Figures 5 to 11; these will not be elaborated upon here.

[0729] For example, the communication device 1600 is used to execute the following scheme:

[0730] Interface module 1601 is used to receive indication information of the first path and indication information of the second path. The first path is used to send the second data packet to the fourth terminal device, and the second path is used to send the second data packet to the ground access gateway. The second data packet is a data packet sent by the third terminal device to the fourth terminal device.

[0731] The processing module 1602 is used to determine the transmission path of the second data packet based on the indication information of the first path and the indication information of the second path.

[0732] In one possible implementation, the indication information for the first path includes the IP address of the third network element, the indication information for the second path includes the IP address of the terrestrial access gateway, and the third network element provides services to the third terminal device.

[0733] In another possible implementation, the interface module 1601 is also used to receive third indication information, which is used to indicate the path of the second data packet to be determined based on the status of the first path or the second path.

[0734] In another possible implementation, the interface module 1601 is also used to receive fourth indication information, which is used to indicate the monitoring of the status of the first path or the second path.

[0735] In another possible implementation, interface module 1601 is also used to receive a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0736] In another possible implementation, the processing module 1602 is also used to monitor the status of the first path and / or the second path.

[0737] It should be understood that the specific procedures for each module to perform the above-mentioned corresponding processes have been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0738] Optionally, when the communication device 1600 is a terminal device or a communication module within a terminal device, the processing module 1602 in the above embodiments can be implemented by at least one processor or processor-related circuitry. Specifically, the processor may include a modem chip, or a system-on-a-chip (SoC) chip containing a modem core, or a system-in-package (SIP) chip. The interface module 1601 can be implemented by a transceiver or transceiver-related circuitry. The interface module 1601 may also be referred to as a communication module or communication interface. The storage module can be implemented by at least one memory.

[0739] Optionally, when the communication device 1600 is a circuit or chip in a terminal device responsible for communication functions, such as a modem chip or a SoC chip or SIP chip containing a modem core, the function of the processing module 1602 can be implemented by a circuit system in the aforementioned chip that includes one or more processors or processing cores. The function of the interface module 1601 can be implemented by the interface circuit or data transceiver circuit on the aforementioned chip.

[0740] The following describes a communication device provided in an embodiment of this application. Please refer to Figure 17, which is a schematic diagram of the structure of a communication device provided in an embodiment of this application. The communication device can be a network device or a terminal device in the above method embodiments, or it can be a chip, chip system, or processor that supports the network device or terminal device in implementing the above methods. This communication device can be used to implement the methods described in the above method embodiments, and for details, please refer to the description in the above method embodiments.

[0741] The communication device may include one or more processors 1701, which are connected to a memory 1702, an input / output unit 1703, and a bus 1704. The processor 1701 may be a general-purpose processor or a dedicated processor, such as a baseband processor or a central processing unit (CPU). The baseband processor can be used to process communication protocols and communication data, while the CPU can be used to control the communication device (e.g., base station, baseband chip, terminal, terminal chip, DU or CU, etc.), execute software programs, and process data from the software programs.

[0742] Optionally, the communication device may include one or more memories 1702, which may store instructions that can be executed on the processor 1701, causing the communication device to perform the methods described in the above method embodiments. Optionally, the memories 1702 may also store data. The processor 1701 and the memories 1702 may be configured separately or integrated together.

[0743] Optionally, the communication device may also include a transceiver and an antenna. A transceiver, also called a transceiver unit, transceiver, or transceiver circuit, is used to implement transmission and reception functions. A transceiver may include a receiver and a transmitter; the receiver, also called a receiver circuit, is used to implement the receiving function; the transmitter, also called a transmitter or transmitting circuit, is used to implement the transmitting function.

[0744] In another possible design, the processor 1701 may include a transceiver for implementing receive and transmit functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing receive and transmit functions may be separate or integrated. The aforementioned transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or for transmitting or relaying signals.

[0745] In another possible design, the processor 1701 may optionally store instructions that, when executed, cause the communication device to perform the methods described in the above method embodiments. The instructions may be stored in the processor 1701; in this case, the processor 1701 may be implemented in hardware.

[0746] In another possible design, the communication device may include a circuit that can perform the sending or receiving or communication functions of the network device or terminal device in the aforementioned method embodiments. The processor and transceiver described in this application embodiment can be implemented on integrated circuits (ICs), analog ICs, radio frequency integrated circuits (RFICs), mixed-signal ICs, application-specific integrated circuits (ASICs), printed circuit boards (PCBs), electronic devices, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductors (CMOS), n-type metal-oxide-semiconductor (NMOS), p-type metal oxide semiconductors (PMOS), bipolar junction transistors (BJTs), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0747] The communication device described in the above embodiments can be a network device or a terminal device, but the scope of the communication device described in the embodiments of this application is not limited thereto, and the structure of the communication device is not limited to FIG17. The communication device can be a standalone device or part of a larger device. For example, the communication device can be:

[0748] (1) Independent integrated circuit IC, or chip, or chip system or subsystem;

[0749] (2) A collection of one or more ICs, optionally including a storage component for storing data and instructions;

[0750] (3) ASIC, such as modem;

[0751] (4) Modules that can be embedded in other devices;

[0752] (5) Receivers, terminals, smart terminals, cellular phones, wireless devices, handheld devices, mobile units, vehicle-mounted devices, network devices, cloud devices, artificial intelligence devices, etc.

[0753] (6) Others, etc.

[0754] For communication devices that can be chips or chip systems, please refer to the schematic diagram of the chip structure shown in Figure 18. The chip 1800 shown in Figure 18 includes a processor 1801 and an interface 1802. Optionally, it may also include a memory 1803. The number of processors 1801 can be one or more, and the number of interfaces 1802 can be multiple.

[0755] For cases where the chip is used to implement the functions of the network device or terminal device in the embodiments of this application:

[0756] The interface 1802 is used to receive or output signals;

[0757] The processor 1801 is used to perform data processing operations on network devices or terminal devices.

[0758] In one possible implementation, the embodiments of this application can be applied to the baseband chip of a network device or terminal device. Transmitting / receiving can correspond to actions related to signal transmission or reception, and can be understood as transmitting / receiving radio frequency signals in the analog / intermediate frequency / radio frequency domain, or as initiating or controlling transmission / reception operations in the digital domain, or a combination of both. For example, when a device transmits or receives various signals, the processor in the device implements the transmission or reception by driving or controlling the radio frequency circuit. Therefore, during signal transmission and reception, the processor is the decision-maker or controller of the transmission and reception operation, while the radio frequency circuit is the specific executor of the transmission and reception; both, in conjunction with the antenna, can jointly realize the transmission and reception operation. The processor includes, but is not limited to, CPUs, DSPs, microprocessors, etc., and the radio frequency circuit includes, but is not limited to, radio frequency chips, radio frequency front-ends, PAs, LNAs, mixers, filters, duplexers, etc., and may also selectively include antennas integrated with the radio frequency circuit.

[0759] It is understood that some optional features in the embodiments of this application can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the communication device given in the embodiments of this application can also implement these features or functions, which will not be elaborated here.

[0760] It should be understood that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the above method embodiments can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor described above can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0761] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAK are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0762] This application also provides a computer-readable storage medium including instructions that, when executed on a computer, cause the computer to perform the methods described in the foregoing embodiments.

[0763] This application also provides a computer program product containing instructions that, when run on a computer, cause the computer to perform the methods described in the foregoing embodiments.

[0764] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0765] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0766] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0767] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0768] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0769] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

Claims

1. A communication method, characterized in that, The method is applied to a session management function network element, and the method includes: Receive a first request message, the first request message including the identification information of a first network element, the first network element being deployed on a first non-terrestrial network device; Path status information is obtained based on the identification information of the first network element. The path status information is used to indicate the path status between the first network element and the second network element. The second network element is deployed on a second non-terrestrial network device. Both the first network element and the second network element are user plane function network elements.

2. The method according to claim 1, characterized in that, The method further includes: Receive a path status notification message, the path status notification message including the path status between the second network element and multiple network elements; The step of obtaining path status information based on the identification information of the first network element includes: The path status information is determined based on the identification information of the first network element and the path status notification message.

3. The method according to claim 1, characterized in that, The step of obtaining path status information based on the identification information of the first network element includes: Send a query request message, the query request message including the identification information of the first network element, the identification information of the first network element being used to obtain the path status between the first network element and the second network element; Receive a first response message, which is a response message to the query request message, and the first response message is used to indicate the path status information.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: Send a second response message, which is a response message to the first request message; wherein, If the path status information indicates that the path status between the first network element and the second network element is available, then the second response message includes the tunnel information of the second network element; Alternatively, if the path status information indicates that the path status between the first network element and the second network element is unavailable, then the second response message includes a path unavailable indication.

5. The method according to any one of claims 1 to 4, characterized in that, The first request message also includes tunnel information of the first network element and the Internet Protocol (IP) address of the first terminal device, and the method further includes: Send a first traffic splitting rule, which instructs the second network element to send a first data packet to the first network element according to the tunnel information of the first network element. The destination address of the first data packet is the IP address of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services to the first terminal device, and the second network element provides services to the second terminal device.

6. The method according to claim 5, characterized in that, The first traffic splitting rule includes: If the path status information indicates that the path status between the first network element and the second network element is available, the first traffic splitting rule is sent.

7. The method according to any one of claims 1 to 4, characterized in that, The first request message also includes tunnel information of the first network element and IP identification information of the first terminal device, and the method further includes: Send a first message, which includes indication information and a first traffic splitting rule. The indication information is used to instruct the second network element to perform traffic splitting according to the first traffic splitting rule when the path status between the first network element and the second network element is available. The first traffic splitting rule is used to instruct the second network element to send the first data packet to the first network element through the tunnel information of the first network element. The destination address of the first data packet is the identification information of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services for the multimedia subsystem IMS session or IMS connection of the first terminal device, and the second network element provides services for the second terminal device. When the path status is available, a successful establishment indication is received; or... When the path status is unavailable, receive a path unavailable indication.

8. The method according to any one of claims 1 to 5, characterized in that, The method further includes: A second traffic splitting rule is sent, which instructs the second network element to send the first data packet to the session anchor point. The destination address of the first data packet is the IP address of the first terminal device. The first data packet is obtained by the second network element from the second terminal device. The first network element provides services to the first terminal device, and the second network element provides services to the second terminal device. The session anchor point is deployed on the first terrestrial network.

9. The method according to claim 8, characterized in that, The second traffic splitting rule includes: When the path status information indicates that the path status between the first network element and the second network element is unavailable, the second traffic splitting rule is sent.

10. The method according to claim 8, characterized in that, The method further includes: Send a first instruction message, which is used to instruct the second network element to use the first traffic splitting rule or the second traffic splitting rule according to the path status information.

11. The method according to claim 10, characterized in that, The message carried by the first indication information also includes the first diversion rule and the second diversion rule.

12. The method according to any one of claims 8 to 11, characterized in that, The method further includes: Receive first information, which is used to indicate that the path status between the first network element and the second network element has changed, or to indicate switching the transmission path between the first network element and the second network element; The first traffic splitting rule includes: The first traffic splitting rule is sent according to the first information; The second traffic splitting rule includes: The second traffic splitting rule is sent based on the first information.

13. The method according to any one of claims 1 to 5, characterized in that, The method further includes: Receive second information, the second information including service flow information between the second terminal device and the ground access gateway, the ground access gateway being deployed in the second ground network, and the ground access gateway and the second network element transmitting data through a session anchor point; In response to the second information, a third traffic splitting rule and a fourth traffic splitting rule are sent. The third traffic splitting rule is used to instruct the second network element to send a third data packet to the session anchor point. The third data packet is a data packet sent by the second terminal device to the terrestrial access gateway. The fourth traffic splitting rule is used to instruct the second network element to send a fourth data packet from the session anchor point to the second terminal device. The fourth data packet is a data packet sent by the terrestrial access gateway to the second terminal device.

14. The method according to claim 13, characterized in that, The method further includes: Receive third information, the third information being used to indicate that the path status between the first network element and the second network element has changed; If, according to the third information, the path status between the first network element and the second network element changes from unavailable to available, then in response to the third information, a path availability indication is sent. or, If, according to the third information, the path status between the first network element and the second network element changes from an available state to an unavailable state, then in response to the third information, a path unavailable indication is sent.

15. The method according to claim 5, characterized in that, The first request message also includes the IP address of the second terminal device and the IP address of the terrestrial access gateway, and the method further includes: A third traffic splitting rule is sent, which instructs the second network element to send a third data packet from the session anchor to the second terminal device. The third data packet is a data packet sent by the terrestrial access gateway to the second terminal device. The terrestrial access gateway is deployed in the second terrestrial network, and the session anchor is deployed in the first terrestrial network. The terrestrial access gateway and the second network element transmit the third data packet through the session anchor.

16. A communication method, characterized in that, The method is applied to the first agent call session control function network element, and the method includes: Obtain the identification information of a third network element, wherein the third network element is deployed on a first non-terrestrial network device; The identification information of the third network element is sent, and the identification information of the third network element is used to obtain the transmission path between the third terminal device and the fourth terminal device. The third network element provides services to the third terminal device. A third response message is received, which is used to indicate the transmission path between the third terminal device and the fourth terminal device. The third network element is a user plane function network element or an access gateway.

17. The method according to claim 16, characterized in that, The third network element is a user plane function network element, and the method further includes: Send a third request message, the third request message including the identification information of the third terminal device; The acquisition of the identification information of the third network element includes: A fourth response message is received, which is a response message to the third request message, and the fourth response message includes the identification information of the third network element.

18. The method according to claim 16 or 17, characterized in that, The third response message includes indication information for a first path and / or indication information for a second path. The first path is the path from the third terminal device to the fourth terminal device via a third network element and a fourth network element. The second path is the path from the third terminal device to the fourth terminal device via a session anchor or a terrestrial access gateway. The fourth network element provides services to the fourth terminal device. The session anchor is deployed in a first terrestrial network, and the terrestrial access gateway is deployed in a second terrestrial network. The session anchor includes a session anchor that provides services to the third terminal device and a session anchor that provides services to the fourth terminal device. The terrestrial access gateway includes a terrestrial access gateway that provides services to the third terminal device and a terrestrial access gateway that provides services to the fourth terminal device.

19. The method according to claim 18, characterized in that, When the fourth network element is a user plane function network element, the indication information of the first path includes the tunnel information of the fourth network element and the IP address of the fourth terminal device; Alternatively, when the fourth network element is an access gateway, the indication information of the first path includes the IP address of the fourth network element; If the second path is the path between the third terminal device and the fourth terminal device through the terrestrial access gateway, the indication information of the second path includes the IP address of the terrestrial access gateway; Alternatively, if the second path is a path between the third terminal device and the fourth terminal device via a session anchor, the indication information of the second path includes the IP address of the fourth terminal device.

20. The method according to claim 18 or 19, characterized in that, The method further includes: Sending call signaling, the call signaling being used to indicate the first path and / or the second path, the call signaling including any one of the following: the IP address of the fourth terminal device, the IP address of the terrestrial access gateway, the IP address of the third network element, wherein the terrestrial access gateway is a terrestrial access gateway serving the third terminal device.

21. The method according to any one of claims 16 to 20, characterized in that, The method further includes: Receive third information, which indicates that the path status of the first path or the second path has changed; Send a fourth message, which is used to indicate whether to switch the first path to the second path, or to indicate whether to switch the second path to the first path.

22. The method according to claim 21, characterized in that, When the fourth information is used to indicate switching the first path to the second path, and the second path is the path between the third terminal device and the fourth terminal device via the terrestrial access gateway, the fourth information includes the IP address of the terrestrial access gateway, which is a terrestrial access gateway providing services to the third terminal device, and the terrestrial access gateway is deployed in a second terrestrial network; or, When the fourth information is used to indicate switching the first path to the second path, and the second path is the path between the third terminal device and the fourth terminal device via a session anchor, the fourth information includes the IP address of the third terminal device; or, When the fourth information indicates that the second path should be switched to the first path, and the third network element is a user plane function network element, the fourth information includes the tunnel information of the third network element and the IP address of the third terminal device, and the third network element provides services to the third terminal device; or, When the fourth information indicates that the second path should be switched to the first path, and both the third network element and the fourth network element are access gateways, the fourth information includes the IP address of the third network element.

23. The method according to claim 21, characterized in that, The method further includes: Send a second instruction message, which includes the address information required by the third terminal device to send session data to the fourth terminal device through a target path, wherein the target path is either the first path or the second path.

24. The method according to any one of claims 18 to 20, characterized in that, The method further includes: Send a fifth message, which includes service flow information between the third terminal device and the ground access gateway.

25. The method according to claim 20, characterized in that, The call signaling also includes third indication information, which is used to instruct the third terminal device to transmit data using the first path or the second path according to the path status of the first path and / or the second path.

26. The method according to claim 20, characterized in that, The call signaling also includes a path selection strategy, which includes one or more of the following: initial path indication, path priority, path delay threshold, or path packet loss rate threshold.

27. The method according to claim 20, characterized in that, The call signaling also includes fourth indication information, which is used to instruct the third terminal device to perform path monitoring in order to obtain the path status of the first path and / or the second path.

28. The method according to claim 16 or 17, characterized in that, The third network element is an access gateway. The third response message includes information about a third path and / or a fourth path. The information about the third path includes the IP address of the fourth network element. The fourth network element is deployed on a second non-terrestrial network device. The fourth network element is an access gateway that serves a fourth terminal device. The information about the fourth path includes the IP address of a terrestrial access gateway. The terrestrial access gateway is deployed on a second terrestrial network and serves the fourth terminal device. The third path is the path from the third terminal device to the fourth terminal device via the third network element and the fourth network element. The fourth path is the path from the fourth terminal device to the fourth terminal device via the third network element and the terrestrial access gateway.

29. The method according to claim 28, characterized in that, The method further includes: Send a fifth instruction message, which is used to instruct the third network element to use the third path or the fourth path to transmit data according to the path status of the third path and / or the fourth path.

30. The method according to claim 28 or 29, characterized in that, The method further includes: Send a path selection strategy, the path selection strategy including one or more of the following: initial path indication, path priority, path delay threshold or path packet loss rate threshold; Send a sixth instruction message, which is used to instruct the third network element to monitor the path status of the third path and / or the fourth path.

31. The method according to claim 30, characterized in that, The method further includes: The transmission path is determined based on the path status information, which is determined based on the identification information of the third network element. The path status information is used to indicate the path status between the third network element and the fourth network element.

32. A communication method, characterized in that, The method is applied to the second agent call session control function network element, and the method includes: The identification information of the third network element is received. The identification information of the third network element is used to obtain the transmission path between the third terminal device and the fourth terminal device. The third network element provides services to the third terminal device. The third network element is a user plane function network element or an access gateway. The third network element is deployed on the first non-terrestrial network device. A third response message is sent, which is used to indicate the transmission path between the third terminal device and the fourth terminal device.

33. The method according to claim 32, characterized in that, The method further includes: Send a second request message, the second request message including the identification information of the third network element; Receive a fourth response message, which is a response message to the second request message. The fourth response message is used to indicate the path establishment status between the third network element and the fourth network element. The fourth network element provides services to the fourth terminal device. The fourth network element is deployed on the second non-terrestrial network device. The transmission path between the third terminal device and the fourth terminal device is determined based on the path establishment status between the third network element and the fourth network element.

34. The method according to claim 33, characterized in that, If the path establishment status between the third network element and the fourth network element is successful, then the fourth response message includes indication information of the first path; or, If the path establishment status between the third network element and the fourth network element is in the establishment failure status, then the fourth response message includes indication information of the second path.

35. The method according to claim 34, characterized in that, When the third network element is a user plane function network element, the indication information of the first path includes the tunnel information of the third network element and the IP address of the fourth terminal device, and the indication information of the second path includes the IP address of the terrestrial access gateway; or, When the third network element is an access gateway, the indication information of the first path includes the IP address of the third network element, and the indication information of the second path includes the IP address of the terrestrial access gateway.

36. The method according to claim 34 or 35, characterized in that, The method further includes: Receive third information, which indicates that the path status of the first path or the second path has changed; Send a fourth message, which is used to indicate switching the first path to the second path, or to indicate switching the second path to the first path.

37. The method according to claim 36, characterized in that, When the fourth information is used to indicate switching the first path to the second path, the fourth information includes the IP address of the ground access gateway, which is deployed in the second ground network; or, When the fourth information indicates that the second path should be switched to the first path, and both the third network element and the fourth network element are user plane function network elements, the fourth information includes the tunnel information of the third network element and the IP address of the third terminal device. or, When the fourth information indicates that the second path should be switched to the first path, and both the third and fourth network elements are access gateways, the fourth information includes the IP address of the fourth network element.

38. The method according to claim 37, characterized in that, The method further includes: Send a second instruction message, which is used to instruct the fourth terminal device to switch the first path to the second path or switch the second path to the first path.

39. The method according to claim 37, characterized in that, The method further includes: Send a fifth message, which includes service flow information between the fourth terminal device and the ground access gateway.

40. The method according to any one of claims 34 to 39, characterized in that, The method further includes: Receive call signaling, the call signaling being used to indicate the first path and / or the second path, the call signaling including any one of the following: the IP address of the fourth terminal device, the IP address of the terrestrial access gateway, the IP address of the third network element, the terrestrial access gateway being a terrestrial access gateway serving the third terminal device.

41. The method according to claim 40, characterized in that, The call signaling also includes third indication information, which is used to instruct the fourth terminal device to transmit data using the first path or the second path according to the path status of the first path and / or the second path.

42. The method according to claim 40 or 41, characterized in that, The call signaling also includes a path selection strategy, which includes one or more of the following: initial path indication, path priority, selection of a path with low latency, selection of a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

43. The method according to any one of claims 40 to 42, characterized in that, The call signaling also includes fourth indication information, which is used to instruct the fourth terminal device to perform path monitoring in order to obtain the path status of the first path and / or the second path.

44. The method according to any one of claims 32 to 43, characterized in that, The third network element is an access gateway. The third response message includes information about a third path and / or a fourth path. The information about the third path includes the IP address of the third network element. The information about the fourth path includes the IP address of the terrestrial access gateway. The terrestrial access gateway is deployed in a second terrestrial network. The third path is the path between the third network element and the fourth network element. The fourth path is the path between the fourth network element and the terrestrial access gateway.

45. The method according to claim 44, characterized in that, The method further includes: Send a fifth instruction message, which is used to instruct the fourth network element to use the third path or the fourth path to transmit data according to the path status of the third path and / or the fourth path.

46. ​​The method according to claim 44 or 45, characterized in that, The method further includes: Send a path selection strategy, the path selection strategy including one or more of the following: initial path indication, path priority, selection of path with low latency, selection of path with low packet loss rate, path latency threshold, and path packet loss rate threshold; Send a sixth instruction message, which is used to instruct the fourth network element to monitor the path status of the third path and / or the fourth path.

47. The method according to any one of claims 32 to 46, characterized in that, When both the third network element and the fourth network element are access gateways, the third response message includes path status information, and the method further includes: The transmission path is determined based on path status information, which is determined based on the identification information of the third network element. The path status information is used to indicate the path status between the third network element and the fourth network element, and the fourth network element provides services to the fourth terminal device.

48. A communication method, characterized in that, The method is applied to a fourth network element, and the method includes: Determine path status information, which is used to indicate the path status between the third network element and the fourth network element. The third network element is deployed on a first non-terrestrial network device, and the fourth network element is deployed on a second non-terrestrial network device. Both the third network element and the fourth network element are user plane function network elements, or both the third network element and the fourth network element are access gateways. Send path status information, which is used to determine the transmission path between the third terminal device and the fourth terminal device. The third network element provides services to the third terminal device, and the fourth network element provides services to the fourth terminal device.

49. The method according to claim 48, characterized in that, The transmission path includes a first path and / or a second path. The first path is the path from the third terminal device to the fourth terminal device through the third network element and the fourth network element. The second path is the path from the third terminal device to the fourth terminal device through a session anchor or a terrestrial access gateway. The session anchor is deployed in a first terrestrial network, or the terrestrial access gateway is deployed in a second terrestrial network.

50. The method according to claim 49, characterized in that, The fourth network element is a user plane function network element, and the method further includes: When the second path is the path between the third terminal device and the fourth terminal device through a session anchor, a first traffic splitting rule and / or a second traffic splitting rule are received. The first traffic splitting rule is used to indicate the first path, and the second traffic splitting rule is used to indicate the second path.

51. The method according to claim 50, characterized in that, The method further includes: Receive first indication information, the first indication information being used to instruct the use of the first traffic splitting rule or the second traffic splitting rule based on the path status information; In response to the first indication information, the transmission path of the first data packet is determined using the first diversion rule or the second diversion rule based on the path status information.

52. The method according to claim 51, characterized in that, The method further includes: If the path status of the first path is available, then the transmission path is determined to be the first path; or, If the path status of the first path is unavailable, then the transmission path is determined to be the second path.

53. The method according to claim 48, characterized in that, The third network element and the fourth network element are access gateways. The transmission path includes a third path and / or a fourth path. The third path is the path between the third network element and the fourth network element. The fourth path is the path between the third network element and the fourth network element through the terrestrial access gateway. The terrestrial access gateway is deployed in the second terrestrial network.

54. The method according to claim 53, characterized in that, The method further includes: The fifth instruction information is received, which is used to instruct the fourth network element to use the third path or the fourth path to transmit data according to the path status of the third path and / or the fourth path.

55. The method according to claim 53 or 54, characterized in that, The method further includes: The path selection strategy includes one or more of the following: initial path indication, path priority, selection of path with low latency, selection of path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

56. The method according to any one of claims 53 to 55, characterized in that, The method further includes: Receive a path state subscription request, the path state subscription request being used to request that when the path state between the fourth network element and any one of the at least one network element changes, a path state notification message be sent. Send the path status notification message, which is used to indicate the path status between the fourth network element and any one of the at least one network element, and the path status notification message includes path status information.

57. The method according to any one of claims 48 to 56, characterized in that, The method further includes: Receive a query request message, the query request message including the identification information of the third network element, the query request message being used to request a query of the path status between the third network element and the fourth network element; Send a first response message, which is a response message to the query request message, and the first response message is used to indicate path status information.

58. A communication method, characterized in that, The method is applied to a terminal device, and the method includes: The system receives indication information from a first path and indication information from a second path. The first path is used to directly send the second data packet to the fourth terminal device, and the second path is used to send the second data packet to the fourth terminal device through a terrestrial access gateway. The second data packet is a data packet sent to the fourth terminal device. The transmission path of the second data packet is determined based on the indication information of the first path and the indication information of the second path.

59. The method according to claim 58, characterized in that, The indication information for the first path includes the IP address of the fourth terminal device, and the indication information for the second path includes the IP address of the ground access gateway, which provides services to the third terminal device.

60. The method according to claim 58 or 59, characterized in that, The method further includes: Receive third indication information, which is used to indicate the path of the second data packet to be determined based on the status of the first path or the second path.

61. The method according to any one of claims 58 to 60, characterized in that, The method further includes: Receive a fourth indication message, which is used to indicate that the status of the first path or the second path is monitored.

62. The method according to any one of claims 58 to 61, characterized in that, The method further includes: The receiving path selection strategy includes one or more of the following: initial path indication, path priority, selection of path with low latency, selection of path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

63. The method according to any one of claims 58 to 62, characterized in that, The method further includes: Monitor the status of the first path and / or the second path.

64. A communication device, characterized in that, It includes modules or units for performing the method as described in any one of claims 1 to 15, or modules or units for performing the method as described in any one of claims 16 to 31, or modules or units for performing the method as described in any one of claims 32 to 47, or modules or units for performing the method as described in any one of claims 48 to 57, or modules or units for performing the method as described in any one of claims 58 to 63.

65. A communication device, characterized in that, include: A processor for executing a program that causes the communication device to perform the method as claimed in any one of claims 1 to 15, or, the method as claimed in any one of claims 16 to 31, or, the method as claimed in any one of claims 32 to 47, or, the method as claimed in any one of claims 48 to 57, or, the method as claimed in any one of claims 58 to 63.

66. A communication system, characterized in that, include: Terminal equipment, first network element, second network element, communication device for performing any of the methods described in steps 1 to 15, and communication device for performing any of the methods described in steps 16 to 31; or, A communication device for performing any of the methods described in steps 58 to 63, a first network element, a second network element, a communication device for performing any of the methods described in steps 32 to 47, a communication device for performing any of the methods described in steps 48 to 57, a communication device for performing any of the methods described in steps 1 to 15, and a communication device for performing any of the methods described in steps 16 to 31.

67. A computer-readable storage medium, characterized in that, The instructions, when executed on a computer, cause the computer to perform the method as claimed in any one of claims 1 to 15, or cause the computer to perform the method as claimed in any one of claims 16 to 31, or cause the computer to perform the method as claimed in any one of claims 32 to 47, or cause the computer to perform the method as claimed in any one of claims 48 to 57, or cause the computer to perform the method as claimed in any one of claims 58 to 63.

68. A computer program product containing instructions, characterized in that, When it is run on a computer, it causes the computer to perform the method as described in any one of claims 1 to 15, or causes the computer to perform the method as described in any one of claims 16 to 31, or causes the computer to perform the method as described in any one of claims 32 to 47, or causes the computer to perform the method as described in any one of claims 48 to 57, or causes the computer to perform the method as described in any one of claims 58 to 63.

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