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 method, communication apparatus, communication system, and storage medium

[0001] The present application claims priority from the Chinese patent application No. 202411401993.3 filed on September 30, 2024, and entitled "Communication method, communication apparatus, communication system, and storage medium", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] Embodiments of the present application relate to the field of communication technology, in particular to a communication method, a communication apparatus, a communication system, and a storage medium. BACKGROUND

[0003] A user equipment (UE) communicates with another UE through an inter-satellite link between satellites is referred to as UE-SAT-UE communication. In existing solutions, a proxy-call session control function (P-CSCF) network element determines whether to enable UE-SAT-UE communication according to whether the calling UE and the called UE access through a satellite.

[0004] In a satellite network, there are reverse orbits, and satellites on the reverse orbits can be adjacent in space for a period of time, but the motion directions of the satellites are opposite. Due to the high relative speed between satellites on opposite orbits, it is difficult to establish an inter-satellite link, and therefore, the satellites on opposite orbits usually cannot communicate with each other through the inter-satellite link, or the inter-satellite link needs to detour a long distance, resulting in a large call delay between UEs. Therefore, the P-CSCF or session management function (SMF) network element needs to query an external system, such as a satellite routing subsystem, to obtain whether direct communication between two satellites based on the inter-satellite link is supported.

[0005] However, the P-CSCF network element or the SMF network element and the external system belong to different fields and are standardized by different organizations, and the interface between them is difficult to standardize, and even if it is standardized, it is difficult to implement among different products. When a 3rd generation partnership project (3GPP) system and an external system belong to different manufacturers, the P-CSCF network element or the SMF network element usually cannot obtain the reachability of the inter-satellite link, and therefore cannot determine the communication link between UEs according to the reachability of the inter-satellite link. SUMMARY

[0006] The embodiment of the present application provides a communication method, a communication device, a communication system and a storage medium. The inter-satellite path is inquired through a network element deployed in a non-ground network device, so that whether to enable UE-SAT-UE communication is determined based on the reachability of the inter-satellite path, and then the problem that the inter-satellite path reachability cannot be inquired due to the non-standardization of external interfaces is avoided.

[0007] The first aspect of the present application provides a communication method. Optionally, the execution subject of the method can be an SMF network element. The SMF network element can be a network device, or a component or device (such as a processor, a chip, or a chip system) applied to the network device, or a logic module or software capable of realizing all or part of the network device functions. Taking the SMF network element as the network device for example, in the method, the SMF network element receives a first request message, the first request message includes identification information of a first network element, and the first network element is deployed in a first non-ground network device; the SMF network element acquires path state information based on the identification information of the first network element, the path state information is used to indicate a path state between the first network element and a second network element, the second network element is deployed in a second non-ground network device, and the first network element and the second network element are both user plane function network elements.

[0008] Based on the first aspect of the present application, the SMF network element acquires the path state information from the satellite-borne UPF, so that the SMF network element does not need to inquire an external system, and the problem that the path state of the inter-satellite link cannot be inquired due to the non-standardization of external interfaces is avoided.

[0009] Based on the first aspect of the present application, in some possible implementation manners, the SMF network element also receives a path state notification message, the path state notification message includes path states between the second network element and multiple network elements. The SMF network element determines the path state information based on the identification information of the first network element and the path state notification message.

[0010] In the embodiment of the present application, the SMF network element can acquire the path states between the second network element and other multiple network elements through the reception of the path state notification message, and the multiple network elements include the first network element. Therefore, the SMF network element can determine the path state between the first network element and the second network element, i.e., the path state information, from the path state notification message according to the identification information of the first network element, so that the SMF network element does not need to inquire an external system to acquire the path state, and the problem that the path state of the inter-satellite link cannot be inquired due to the non-standardization of external interfaces is avoided.

[0011] In some possible implementation manners based on the first aspect of the present application, the SMF network element sends a query request message, the query request message includes the identification information of the first network element, and 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. The SMF network element receives a first response message, the first response message is a response message of the query request message, and the first response message is used to indicate the path status information.

[0012] In the implementation manners of the present application, the SMF network element enables the receiver of the query request message to query the path status between the first network element and the second network element according to the identification of the first network element carried in the query request message. The SMF network element obtains the path status information from the first response message by receiving the first response message, thereby avoiding the problem that the path status of the inter-star link cannot be queried due to the non-standardization of external interfaces.

[0013] In some possible implementation manners based on the first aspect of the present application, the SMF network element also sends a second response message, the second response message is a response message of 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 an available state, 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 an unavailable state, the second response message includes a path-unavailable indication.

[0014] In the implementation manners of the present application, the SMF network element enables the receiver of the second response message to obtain the path status indicated by the second response message.

[0015] In some possible implementation manners based on the first aspect of the present application, 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, and the SMF network element also sends a first split rule, the first split rule is used to instruct 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 a second terminal device, the first network element provides services for the first terminal device, and the second network element provides services for the second terminal device.

[0016] In the implementation manners of the present application, the SMF network element instructs the second network element to transmit the data packet based on the first split rule, thereby establishing the inter-star link.

[0017] In some possible implementation manners based on the first aspect of the present application, when the path status information indicates that the path status between the first network element and the second network element is an available state, the SMF network element sends the first split rule.

[0018] In the embodiments of the present application, the SMF network element sends the first split rule only when the path is available, avoiding the establishment of the inter-satellite link when the path is unavailable, which leads to the failure of the session.

[0019] Based on the first aspect of the present application, in some possible embodiments, the first request message further comprises tunnel information of the first network element and Internet Protocol (IP) address information of the first terminal device, and the SMF network element sends a first message comprising the indication information and the first split rule, the indication information being used to instruct the second network element to split according to the first split rule when the path state between the first network element and the second network element is in the available state, the first split rule being used to instruct the second network element to send a 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 being the identification information of the first terminal device, the first data packet being obtained by the second network element from a second terminal device, the first network element providing services for an IMS session or IMS connection of the first terminal device, and the second network element providing services for the second terminal device; when the path state is in the available state, the SMF network element receives an establishment success indication, or when the path state is in the unavailable state, the SMF network element receives a path unavailable indication.

[0020] In the embodiments of the present application, the SMF network element sends the indication information at the same time of sending the first split rule, so that the receiver of the first message directly establishes the inter-satellite path when the path is available, i.e. directly uses the first split rule for splitting, or returns the path unavailable indication when the path is unavailable. Therefore, the SMF network element does not need to obtain the path state, reducing the signaling overhead.

[0021] Based on the first aspect of the present application, in some possible embodiments, the SMF network element further sends a second split rule, the second split rule being used to instruct the second network element to send the first data packet to a session anchor, the destination address of the first data packet being the IP address of the first terminal device, the first data packet being obtained by the second network element from the second terminal device, the first network element providing services for the first terminal device, the second network element providing services for the second terminal device, and the session anchor being deployed in the first ground network.

[0022] In the embodiments of the present application, the SMF network element sends the second split rule, so that the receiver of the second split rule can transmit the data packet through the ground path based on the second split rule. Therefore, the receiver of the second split rule can switch the transmission path when the inter-satellite path is unavailable, and use the ground path, so as to guarantee the continuity of the session and prevent the session from being interrupted.

[0023] Based on the first aspect of the present application, in some possible embodiments, when the path state information indicates that the path state between the first network element and the second network element is in the unavailable state, the SMF network element sends the second split rule.

[0024] In the embodiments of the present application, the SMF network element sends the second splitting rule when the inter-satellite path is unavailable, so that a path passing through the ground session anchor network element can be established for the call between the first terminal device and the second terminal device when the inter-satellite path is unavailable, and the session interruption is prevented.

[0025] Based on the first aspect of the present application, in some possible embodiments, the SMF network element further sends first indication information, and the first indication information is used to instruct the second network element to use the first splitting rule or the second splitting rule according to the path state information.

[0026] In the embodiments of the present application, the SMF network element sends the first indication information, so that the receiver of the first indication information can select to use the inter-satellite path or the ground path according to the path state information, thereby guaranteeing the continuity of the session and preventing the session interruption.

[0027] Based on the first aspect of the present application, in some possible embodiments, the SMF network element sends the first indication information when sending the first splitting rule and the second splitting rule. The SMF network element establishes two paths, i.e., the ground path and the inter-satellite path, for the call between the first terminal device and the second terminal device, and instructs the receiver to dynamically select the inter-satellite path or the ground path based on the path state. For example, when the inter-satellite path is unavailable, the ground path can be automatically selected, thereby guaranteeing the continuity of the session and preventing the session interruption.

[0028] Based on the first aspect of the present application, in some possible embodiments, the SMF network element further receives first information, and the first information is used to instruct that the path state between the first network element and the second network element changes, or is used to instruct to switch the transmission path between the first network element and the second network element; and the SMF network element sends the first splitting rule or the second splitting rule according to the first information.

[0029] In the embodiments of the present application, when the path state between the first network element and the second network element changes, the SMF network element sends the first splitting rule or the second splitting rule to instruct to switch the transmission path, thereby guaranteeing the continuity of the session and preventing the session interruption when the path state between the first network element and the second network element changes.

[0030] In some possible implementation of the first aspect of the present application, the SMF network element further receives second information, the second information comprising traffic information between the second terminal device and a ground access gateway, the ground access gateway being deployed in a second ground network, and the ground access gateway and the second network element transmitting data via a session anchor. In response to the second information, the SMF network element sends a third split rule and a fourth split rule, the third split rule being used to instruct the second network element to send a third data packet to the session anchor, the third data packet being a data packet sent by the second terminal device to the ground access gateway, and the fourth split rule being used to instruct the second network element to send a fourth data packet from the session anchor to the second terminal device, the fourth data packet being a data packet sent by the ground access gateway to the second terminal device.

[0031] In the implementation of the present application, the SMF network element sends the third split rule and the fourth split rule, so that the receiver of the third split rule and the fourth split rule can realize the transmission of the data packet via the ground access gateway.

[0032] In some possible implementation of the first aspect of the present application, the SMF network element further receives third information, the third information being used to indicate that the path state between the first network element and the second network element changes. If the path state between the first network element and the second network element changes from the unavailable state to the available state according to the third information, the SMF network element sends a path available indication in response to the third information; or if the path state between the first network element and the second network element changes from the available state to the unavailable state according to the third information, the SMF network element sends a path unavailable indication in response to the third information.

[0033] In the implementation of the present application, the SMF network element sends the path available indication or the path unavailable indication when the path state between the first network element and the second network element changes, so that the receiver of the indication can determine whether the inter-satellite link is available based on the path available indication or the path unavailable indication.

[0034] In some possible implementation of the first aspect of the present application, the first request message further comprises an IP address of the second terminal device and an IP address of the ground access gateway, and the SMF network element further sends a third split rule, the third split rule being used to instruct the second network element to send a third data packet from the session anchor to the second terminal device, the third data packet being a data packet sent by the ground access gateway to the second terminal device, the ground access gateway being deployed in a second ground network, the session anchor being deployed in a first ground network, and the ground access gateway and the second network element transmitting the third data packet via the session anchor.

[0035] In the embodiments of the present application, since the first request message further comprises the IP address of the second terminal device and the IP address of the ground access gateway, the SMF network element can send a third offloading rule, so that the reception of the third offloading rule completes data transmission based on the ground path.

[0036] The second aspect of the present application provides a communication method. Optionally, the execution subject of the method can be a first proxy-call session control function (P-CSCF). The first P-CSCF can be a network device, or a component or apparatus (such as a processor, a chip, or a chip system) applied to the network device, or a logic module or software capable of realizing all or part of the functions of the network device. Taking the first P-CSCF as a network device as an example, in the method, the first P-CSCF obtains identification information of a third network element, and the third network element is deployed in a first non-terrestrial network device. The first P-CSCF sends the identification information of the third network element, and the identification information of the third network element is used to obtain a transmission path between a third terminal device and a fourth terminal device, and the third network element provides services for the third terminal device. The first P-CSCF receives a third response message, and the third response message is used to indicate the transmission path between the third terminal device and the fourth terminal device, and the third network element is a user plane function network element or an access gateway.

[0037] Based on the second aspect of the present application, the first P-CSCF can obtain and send the identification information of the third network element, so that the receiver of the identification information of the third network element can determine the transmission path between the third terminal device and the fourth terminal device according to the identification information, and return the first P-CSCF, so that the first P-CSCF does not need to query an external system, and the problem that the path state of the inter-satellite link cannot be queried due to the non-standardization of the external interface is avoided.

[0038] Based on the second aspect of the present application, in some possible embodiments, the third network element is a user plane function network element, and the first P-CSCF further sends a third request message, and the third request message comprises identification information of the third terminal device. The first P-CSCF receives a fourth response message, and the fourth response message is a response message of the third request message, and the fourth response message comprises the identification information of the third network element.

[0039] In some possible implementation manners based on the second aspect of the present application, the third response message comprises indication information of the first path and / or indication information of the second path, the first path is a path between the third terminal device and the fourth terminal device through the third network element and the fourth network element, the second path is a path between the third terminal device and the fourth terminal device through the session anchor or the ground access gateway, the fourth network element provides service for the fourth terminal device, the session anchor is deployed in the first ground network, and the ground access gateway is deployed in the second ground network, wherein the session anchor comprises a session anchor providing service for the third terminal device and a session anchor providing service for the fourth terminal device, and the ground access gateway comprises a ground access gateway providing service for the third terminal device and a ground access gateway providing service for the fourth terminal device.

[0040] In the implementation manners of the present application, the third response message can comprise two paths, i.e., an inter-satellite path and a ground path. The first path is the inter-satellite path, and the second path is the ground path, so that the first P-CSCF can use the inter-satellite path or the ground path to transmit the data packet between the third terminal device and the fourth terminal device according to the indication of the third response message, thereby guaranteeing that a usable path is selected between the third terminal device and the fourth terminal device, guaranteeing the continuity of the session, and preventing the session from being terminated. When the third response message comprises the ground path and the inter-satellite path at the same time, the first P-CSCF can support dynamically selecting the inter-satellite path or the ground path according to the path state, thereby guaranteeing the continuity of the session and preventing the session from being interrupted.

[0041] In some possible implementation manners based on the second aspect of the present application, when the fourth network element is a user plane function network element, the indication information of the first path comprises tunnel information of the fourth network element and an IP address of the fourth terminal device; or, when the fourth network element is an access gateway, the indication information of the first path comprises an 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 the ground access network element, the indication information of the second path comprises an IP address of the ground access gateway; or, when the second path is a path between the third terminal device and the fourth terminal device through the session anchor, the indication information of the second path comprises an IP address of the fourth terminal device.

[0042] In some possible implementation manners based on the second aspect of the present application, the first P-CSCF further sends a call signaling to the terminal device, and the call signaling is used to indicate the first path and / or the second path.

[0043] The call signaling comprises any one of the following: an IP address of the fourth terminal device, an IP address of the ground access gateway, wherein the ground access gateway is a ground access gateway providing service for the third terminal device, and an IP address of the third network element.

[0044] Case A: When the third response message indicates the first path and the third network element is a user plane function network element, the IP address of the fourth terminal device is included in the call signaling. In this case, the third terminal device sends the session data packets to the fourth terminal device directly through the IP address of the fourth terminal device.

[0045] Case B: When the fourth response message indicates the first path and the third network element is an access gateway, the IP address of the third network element is included in the call signaling. In this case, the third terminal device sends the session data packets to the fourth terminal device through the third network element first, and then the third network element sends the session data packets to the fourth terminal device.

[0046] Case 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 point, the IP address of the fourth terminal device is included in the call signaling. In this case, the third terminal device sends the session data packets to the fourth terminal device directly through the IP address of the fourth terminal device.

[0047] Case 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 through the ground access gateway, the IP address of the ground access gateway is included in the call signaling, wherein the ground access gateway is the ground access gateway serving the third terminal device. In this case, the third terminal device sends the session data packets to the fourth terminal device through the ground access gateway serving the third terminal device first, and then the ground access gateway sends the session data packets to the fourth terminal device.

[0048] When the fourth response message indicates both the first path and the second path, the information included in the above-mentioned case A or case B and the information corresponding to the case C or case D are included in the call signaling respectively.

[0049] In the embodiments of the present application, the first P-CSCF can determine the call signaling sent to the terminal device according to the path indication of the third response message, so that the terminal device can send the session information through the path indicated by the third response message, avoid sending the message through the unavailable path, and thus guarantee the continuity of the session and prevent the session from being interrupted.

[0050] Based on the second aspect of the present application, in some possible embodiments, the first P-CSCF also receives third information, the third information being used to indicate that the path state of the first path or the second path changes. The first P-CSCF also sends fourth information, the fourth information being used to indicate that the first path is switched to the second path, or used to indicate that the second path is switched to the first path.

[0051] In the embodiments of the present application, the first P-CSCF sends fourth information to the second P-CSCF to indicate the second P-CSCF to switch the path, so that when the path state changes, the session path can be switched to an available path, the continuity of the session is ensured, and the session interruption is prevented.

[0052] Based on the second aspect of the present application, in some possible embodiments, when the fourth information is used to indicate that the first path is switched to the second path, and the second path is a path between the third terminal device and the fourth terminal device through a ground access gateway, the fourth information includes an IP address of the ground access gateway, the ground access gateway is a ground access gateway that provides services for the third terminal device, and the ground access gateway is deployed in the second ground network; or, when the fourth information is used to indicate that the first path is switched to the second path, and the second path is a path between the third terminal device and the fourth terminal device through a session anchor point, the fourth information includes an IP address of the third terminal device; or, 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 tunnel information of the third network element and an IP address of the third terminal device, and the third network element provides services for the third terminal device; or, when the fourth information indicates that the second path is switched to the first path, and the third network element and the fourth network element are both access gateways, the fourth information includes an IP address of the third network element.

[0053] In the embodiments of the present application, the first P-CSCF sends IP address information required by a target path to the second P-CSCF in the fourth information, so that the second P-CSCF can switch the communication path to the target path, and further ensure that the session does not interrupt.

[0054] Based on the second aspect of the present application, in some possible embodiments, the first P-CSCF also sends second indication information, and the second indication information includes address information required by the third terminal device to send session data to the fourth terminal device through a target path, and the target path is the first path or the second path.

[0055] When the target path is the above case A, the second indication information is used to instruct the third terminal device to send the session data packet to the fourth terminal device directly through the IP address of the fourth terminal device.

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

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

[0058] When the target path is the case D, the second indication information is used to instruct the third terminal device to send the session data packet sent to the fourth terminal device to the ground access gateway serving the third terminal device first, and then send the session data packet to the fourth terminal device by the ground access gateway.

[0059] In the embodiment of the application, the first P-CSCF sends the second indication information to instruct the third terminal device to switch the path, so that when the path state changes, the third terminal device can switch the session data to the target path according to the second indication information, thereby guaranteeing the continuity of the session and preventing the session from being interrupted.

[0060] Based on the second aspect of the application, in some possible embodiments, the first P-CSCF also sends fifth information, and the fifth information includes the service flow information between the third terminal device and the ground access gateway.

[0061] In the embodiment of the application, in the path switching process, the first P-CSCF sends the fifth information to instruct the SMF network element to switch the inter-satellite path to the ground path.

[0062] Based on the second aspect of the application, in some possible embodiments, the call signaling also includes third indication information, and the third indication information is used to instruct the third terminal device to use the first path or the second path to transmit data according to the path state of the first path and / or the second path.

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

[0064] Based on the second aspect of the application, in some possible embodiments, the call signaling also includes a path selection strategy, and the path selection strategy includes one or more of the initial path indication, the path priority, the path with low selection delay, the path with low packet loss rate, the path delay threshold, and the path packet loss rate threshold.

[0065] In the embodiment of the application, the first P-CSCF carries the path selection strategy in the call signaling, so that the terminal device can use the first path or the second path to transmit data according to the path selection strategy.

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

[0067] In some possible implementation manners based on the second aspect of the present application, the third network element is an access gateway, the third response message comprises information of the third path and / or information of the fourth path, the information of the third path comprises an IP address of a fourth network element, the fourth network element is deployed in a second non-terrestrial network device, the fourth network element is an access gateway, the fourth network element provides services for a fourth terminal device, the information of the fourth path comprises an IP address of a terrestrial access gateway, the terrestrial access gateway is deployed in a second terrestrial network, the third path is a path between the third terminal device and the fourth terminal device through the third network element and the fourth network element, and the fourth path is a path between the third terminal device and the fourth terminal device through the third network element and the terrestrial access gateway.

[0068] In some possible implementation manners based on the second aspect of the present application, the first P-CSCF further sends fifth indication information, the fifth indication information is used to instruct the third network element to use the third path or the fourth path to transmit data according to the path state of the third path and / or the fourth path.

[0069] In some possible implementation manners based on the second aspect of the present application, the first P-CSCF further sends a path selection policy, the path selection policy comprises one or more of initial path indication, path priority, selecting a path with low latency, selecting a path with low packet loss rate, path latency threshold, and path packet loss rate threshold. The first P-CSCF further sends sixth indication information, the sixth indication information is used to instruct the third network element to monitor the path state of the third path and / or the fourth path.

[0070] In some possible implementation manners based on the second aspect of the present application, the first P-CSCF further determines a transmission path based on path state information, the path state information is determined based on the identification information of the third network element, and the path state information is used to indicate the path state between the third network element and a fourth network element, the fourth network element provides services for a fourth terminal device.

[0071] The third aspect of the present application provides a communication method. Optionally, an execution subject of the method can be a second P-CSCF. The second P-CSCF can be a network device, or a component or apparatus (for example, a processor, a chip, or a chip system) applied to the network device, or a logic module or software capable of realizing all or part of the functions of the network device. Taking the second P-CSCF as the network device as an example, in the method, the second P-CSCF receives identification information of a third network element, the identification information of the third network element is used to obtain a transmission path between a third terminal device and a fourth terminal device, the third network element provides services for 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 in a first non-terrestrial network device. The second P-CSCF sends a third response message, the third response message is used to instruct the transmission path between the third terminal device and the fourth terminal device.

[0072] According to the third aspect of the present application, the second P-CSCF determines the transmission path based on the identifier of the third network element, thereby avoiding the problem that the path state of the inter-satellite link cannot be queried due to the non-standardization of the external interface.

[0073] According to the third aspect of the present application, in some possible implementation manners, the second P-CSCF sends a second request message, and the second request message comprises the identifier information of the third network element. The second P-CSCF receives a fourth response message, and the fourth response message is a response message of the second request message. The fourth response message is used to indicate the path establishment state between the third network element and a fourth network element. The fourth network element provides services for a fourth terminal device, and the fourth network element is deployed in the second non-terrestrial network device. The second P-CSCF determines the transmission path between the third terminal device and the fourth terminal device based on the path establishment state between the third network element and the fourth network element.

[0074] In the implementation manners of the present application, the second P-CSCF determines the path establishment state between the third network element and the fourth network element based on the path state between the third network element and the fourth network element, thereby being able to directly indicate the path establishment state to the receiver of the fourth response message through the fourth response message, and improving the efficiency of session establishment. According to the third aspect of the present application, in some possible implementation manners, the third response message comprises the indication information of the first path or the indication information of the second path. 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. The second path is the path between the third terminal device and the fourth terminal device through the session anchor or the ground access gateway. The fourth network element provides services for the fourth terminal device. The session anchor is deployed in the first ground network. The ground access gateway is deployed in the second ground network.

[0075] According to the third aspect of the present application, in some possible implementation manners, if the path establishment state between the third network element and the fourth network element is the establishment success state, the fourth response message comprises the indication information of the first path. Or, if the path establishment state between the third network element and the fourth network element is the establishment failure state, the fourth response message comprises the indication information of the second path.

[0076] In the implementation manners of the present application, the second P-CSCF determines the content carried by the fourth response message based on different path establishment states, thereby directly indicating the transmission path to the receiver of the fourth response message through the fourth response message, and improving the efficiency of session establishment.

[0077] In some possible implementation manners based on the third aspect of the present application, when the third network element is a user plane function network element, the indication information of the first path comprises tunnel information of the third network element and an IP address of the fourth terminal device; or, when the third network element is an access gateway, the indication information of the first path comprises an IP address of the third network element; and the indication information of the second path comprises an IP address of the ground access gateway.

[0078] In some possible implementation manners based on the third aspect of the present application, the second P-CSCF further sends a call signaling, and the call signaling comprises an IP address of the third terminal device and / or an IP address of the ground access gateway; or, when the third network element is an access gateway, the call signaling comprises an IP address of the fourth network element and / or an IP address of the ground access gateway.

[0079] In some possible implementation manners based on the third aspect of the present application, the second P-CSCF further receives third information, and the third information is used to indicate that a path state of the first path or the second path changes; and the second P-CSCF further sends fourth information, and the fourth information is used to indicate that the first path is switched to the second path or used to indicate that the second path is switched to the first path.

[0080] In some possible implementation manners based on the third aspect of the present application, when the fourth information is used to indicate that the first path is switched to the second path, the fourth information comprises an IP address of the ground access gateway, and the ground access gateway is deployed in the second ground network; or, when the fourth information indicates that the second path is switched to the first path and the third network element and the fourth network element are both user plane function network elements, the fourth information comprises tunnel information of the third network element and an IP address of the third terminal device; or, when the fourth information indicates that the second path is switched to the first path and the third network element and the fourth network element are both access gateways, the fourth information comprises an IP address of the fourth network element.

[0081] In some possible implementation manners based on the third aspect of the present application, the second P-CSCF further sends second indication information, and the second indication information is used to indicate that the fourth terminal device switches the first path to the second path or switches the second path to the first path.

[0082] In some possible implementation manners based on the third aspect of the present application, the second P-CSCF further sends fifth information, and the fifth information comprises service flow information between the fourth terminal device and the ground access gateway.

[0083] In some possible implementation manners based on the third aspect of the present application, the call signaling further comprises third indication information, and the third indication information is used to indicate that the fourth terminal device uses the first path or the second path to transmit data according to a path state of the first path and / or the second path.

[0084] In some possible implementation manners based on the third aspect of the present application, the call signaling further comprises a path selection policy, and the path selection policy comprises one or more of an initial path indication, a path priority, a path with a low latency, a path with a low packet loss rate, a path latency threshold, and a path packet loss rate threshold.

[0085] In some possible implementation manners based on the third aspect of the present application, the call signaling further comprises fourth indication information, and the fourth indication information is used to instruct the fourth terminal device to perform path monitoring to obtain a path state of the first path and / or the second path.

[0086] In some possible implementation manners based on the third aspect of the present application, the third network element is an access gateway, the third response message comprises information of the third path and / or information of the fourth path, the information of the third path comprises an IP address of the third network element, the information of the fourth path comprises an IP address of a ground access gateway, the ground access gateway is deployed in a second ground network, the third path is a path between the third network element and the fourth network element, and the fourth path is a path between the fourth network element and the ground access gateway.

[0087] In some possible implementation manners based on the third aspect of the present application, the second P-CSCF further sends fifth indication information, and the fifth indication information is used to instruct the fourth network element to use the third path or the fourth path to transmit data according to a path state of the third path and / or the fourth path.

[0088] In some possible implementation manners based on the third aspect of the present application, the second P-CSCF further sends a path selection policy, and the path selection policy comprises one or more of an initial path indication, a path priority, a path with a low latency, a path with a low packet loss rate, a path latency threshold, and a path packet loss rate threshold. The second P-CSCF further sends sixth indication information, and the sixth indication information is used to instruct the fourth network element to monitor a path state of the third path and / or the fourth path.

[0089] In some possible implementation manners based on the third aspect of the present application, when the third network element and the fourth network element are both access gateways, the third response message comprises path state information, the second P-CSCF further determines a transmission path based on the path state information, the path state information is determined based on identification information of the third network element, the path state information is used to instruct a path state between the third network element and the fourth network element, and the fourth network element provides services for the fourth terminal device.

[0090] In the implementation manners of the present application, the second P-CSCF can obtain path state information from the satellite access gateway, and thus determines a transmission path based on the path state information, so that the second P-CSCF does not need to query an external system, and the problem that an intersatellite path reachability cannot be queried due to the fact that external interfaces cannot be standardized is avoided.

[0091] The fourth aspect of the present application provides a communication method. Optionally, an execution subject of the method can be a fourth network element. The fourth network element can be a network device, a component or apparatus (for example, a processor, a chip, or a chip system) applied to the network device, or a logic module or software capable of realizing all or part of the network device functions. Taking the fourth network element as the network device as an example, in the method, the fourth network element determines path state information. The path state information is used to indicate a path state between a third network element and the fourth network element. The third network element is deployed in a first non-terrestrial network device, and the fourth network element is deployed in a second non-terrestrial network device. The third network element and the fourth network element are both user plane function network elements, or the third network element and the fourth network element are both access gateways. The fourth network element sends the path state information. The path state information is used to determine a transmission path between a third terminal device and a fourth terminal device. The third network element provides services for the third terminal device, and the fourth network element provides services for the fourth terminal device.

[0092] Based on the fourth aspect of the present application, the fourth network element can determine the path state between the third network element and the fourth network element. The path state 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 ground path. Therefore, when selecting the transmission path between the terminal devices, the path state can be selected according to the path state, and the transmission between the terminal devices is guaranteed to be performed through the available path.

[0093] Based on the fourth aspect of the present application, in some possible implementation manners, the transmission path includes a first path and / or a second path. The first path is a path between the third terminal device and the fourth terminal device through the third network element and the fourth network element. The second path is a path between the third terminal device and the fourth terminal device through a session anchor or a ground access gateway. The session anchor is deployed in a first ground network, or the ground access gateway is deployed in a second ground network.

[0094] In the implementation manners of the present application, the fourth network element can determine the path state between the third network element and the fourth network element. The path state 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 ground path. Therefore, when selecting the transmission path between the terminal devices, the path state can be selected according to the path state, and the transmission between the terminal devices is guaranteed to be performed through the available path.

[0095] In a possible implementation of the fourth aspect of the present application, the fourth network element is a user plane function network element, and when the second path is a path between the third terminal device and the fourth terminal device through a session anchor, the fourth network element further receives a first split rule and / or a second split rule, the first split rule being used to indicate the first path, and the second split rule being used to indicate the second path. The first split rule is used to indicate that the second network element sends the first data packet to the first network element according to the tunnel information of the first network element, the first data packet has a destination address of an 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 for the first terminal device, and the second network element provides services for the second terminal device. The second split rule is used to indicate that the second network element sends the first data packet to the session anchor, the first data packet has a destination address of an 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 for the first terminal device, the second network element provides services for the second terminal device, and the session anchor is deployed in the first ground network.

[0096] In a possible implementation of the fourth aspect of the present application, the fourth network element further receives first indication information, the first indication information being used to indicate that the first split rule or the second split rule is used according to the path state information. The fourth network element determines the transmission path of the first data packet according to the first split rule or the second split rule according to the path state information in response to the first indication information.

[0097] In a possible implementation of the fourth aspect of the present application, if the path state of the first path is an available state, the fourth network element determines that the transmission path is the first path; or if the path state of the first path is an unavailable state, the fourth network element determines that the transmission path is the second path.

[0098] In a possible implementation of the fourth aspect of the present application, 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, the third path being a path between the third network element and the fourth network element, and the fourth path being a path between the third network element and the fourth network element through a ground access gateway, the ground access gateway being deployed in a second ground network.

[0099] In the implementation of the present application, because the transmission path includes the third path and the fourth path, the fourth network element can guarantee the continuity of the session and prevent the session from being interrupted when the path state changes.

[0100] In a possible implementation of the fourth aspect of the present application, when the fourth network element is an access gateway, the fourth network element further receives fifth indication information, the fifth indication information being used to indicate that the fourth network element uses the third path or the fourth path to transmit data according to the path state of the third path and / or the fourth path.

[0101] According to the fourth aspect of the present application, in some possible implementation, the fourth network element further receives a path selection policy, the path selection policy comprising one or more of an initial path indication, a path priority, a path with a low latency, a path with a low packet loss rate, a path latency threshold, and a path packet loss rate threshold.

[0102] According to the fourth aspect of the present application, in some possible implementation, the fourth network element receives a path state subscription request, the path state subscription request being used to request the fourth network element to send a path state notification message when a path state between the fourth network element and any of the at least one network element changes. The fourth network element sends the path state notification message, the path state notification message being used to indicate the path state between the fourth network element and any of the at least one network element, the path state notification message comprising path state information.

[0103] In the implementation of the present application, the fourth network element sends the path state notification message, so that the receiver of the path state 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 non-standardization of external interfaces.

[0104] According to the fourth aspect of the present application, in some possible implementation, the fourth network element further receives a query request message, the query request message comprising identification information of the third network element, the query request message being used to request a query of a path state between the third network element and the fourth network element. The fourth network element further sends a first response message, the first response message being a response message of the query request message, the first response message being used to indicate the path state information.

[0105] According to the fourth aspect of the present application, in some possible implementation, the fourth network element further sends first information, the first information being used to indicate a change of a path state between the fourth network element and any of the at least one network element.

[0106] The fifth aspect of the present application provides an information transmission method. Optionally, the execution subject of the method can be a terminal device, a component or apparatus (for example, a processor, a chip, or a chip system) applied to the terminal device, or a logic module or software capable of realizing all or part of the functions of the terminal device. Taking a third terminal device as an example, the third terminal device receives indication information of a first path and indication information of a second path, the first path being used to directly send a second data packet to a fourth terminal device, and the second path being used to send the second data packet to the fourth terminal device through a ground access gateway, the second data packet being a data packet sent by the third terminal device to the fourth terminal device. The third terminal device determines a transmission path of the second data packet according to the indication information of the first path and the indication information of the second path.

[0107] Based on the fifth aspect of the present application, the third terminal device receives the first path and the second path, so that the third terminal device can dynamically select the inter-satellite path or the ground path according to the path state, select the optimal path, and thus provide better call experience for the user.

[0108] Based on the fifth aspect of the present application, in some possible implementation manners, the indication information of the first path includes an IP address of the fourth terminal device, and the indication information of the second path includes an IP address of the ground access gateway, which provides services for the third terminal device.

[0109] Based on the fifth aspect of the present application, in some possible implementation manners, the third terminal device further receives third indication information, which is used to indicate the path of the second data packet according to the state of the first path or the second path.

[0110] Based on the fifth aspect of the present application, in some possible implementation manners, the third terminal device further receives fourth indication information, which is used to indicate the monitoring of the state of the first path or the second path.

[0111] Based on the fifth aspect of the present application, in some possible implementation manners, the third terminal device further receives a path selection strategy, which includes one or more of the initial path indication, the path priority, the path with low selection delay, the path with low packet loss rate, the path delay threshold, and the path packet loss rate threshold.

[0112] Based on the fifth aspect of the present application, in some possible implementation manners, the third terminal device further monitors the state of the first path and / or the second path.

[0113] The sixth aspect of the present application provides a communication apparatus, including:

[0114] An interface module is configured to receive a first request message, the first request message including identification information of a first network element, the first network element being deployed in a first non-terrestrial network device.

[0115] A processing module is configured to acquire path state information based on the identification information of the first network element, the path state information being used to indicate the path state between the first network element and a second network element, the second network element being deployed in a second non-terrestrial network device, and the first network element and the second network element both being user plane function network elements.

[0116] Optionally, the interface module is further configured to receive a path state notification message, the path state notification message including the path state between the second network element and a plurality of network elements.

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

[0118] Optionally, the interface module is further configured to send a query request message, the query request message comprising 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.

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

[0120] Optionally, the interface module is further configured to send a second response message, the second response message being a response message of 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 an available state, the second response message comprises tunnel information of the second network element.

[0121] Or, if the path status information indicates that the path status between the first network element and the second network element is an unavailable state, the second response message comprises a path-unavailable indication.

[0122] Optionally, the first request message further comprises tunnel information of the first network element and an Internet Protocol (IP) address of the first terminal device, and the interface module is further configured to send a first offloading rule, the first offloading rule being used to instruct 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 first data packet having a destination address of the IP address of the first terminal device, the first data packet being obtained by the second network element from a second terminal device, the first network element providing service for the first terminal device, and the second network element providing service for the second terminal device.

[0123] Optionally, the interface module is specifically configured to send the first offloading rule when the path status information indicates that the path status between the first network element and the second network element is an available state.

[0124] Optionally, the interface module is further configured to send a second offloading rule, the second offloading rule being used to instruct the second network element to send the first data packet to a session anchor, the first data packet having a destination address of the IP address of the first terminal device, the first data packet being obtained by the second network element from the second terminal device, the first network element providing service for the first terminal device, the second network element providing service for the second terminal device, and the session anchor being deployed in a first ground network.

[0125] Optionally, the interface module is specifically configured to send the second offloading rule when the path status information indicates that the path status between the first network element and the second network element is an unavailable state.

[0126] Optionally, the interface module is further configured to send first indication information, the first indication information being used to instruct the second network element to use the first offloading rule or the second offloading rule according to the path status information.

[0127] Optionally, the interface module is specifically configured to send the first indication information when sending the first split rule and the second split rule.

[0128] Optionally, the interface module is further configured to receive first information, the first information being used to indicate that a path state between the first network element and the second network element changes, or being used to indicate that a transmission path between the first network element and the second network element is switched.

[0129] The interface module is specifically configured to send the first split rule according to the first information.

[0130] The interface module is specifically configured to send the second split rule according to the first information.

[0131] Optionally, the interface module is further configured to receive second information, the second information including service flow information between a second terminal device and a ground access gateway, the ground access gateway being deployed in a second ground network, and the ground access gateway and the second network element transmitting data through a session anchor.

[0132] The interface module is specifically configured to send, in response to the second information, a third split rule and a fourth split rule, the third split rule being used to instruct the second network element to send a third data packet to the session anchor, the third data packet being a data packet sent by the second terminal device to the ground access gateway, and the fourth split rule being used to instruct the second network element to send a fourth data packet from the session anchor to the second terminal device, the fourth data packet being a data packet sent by the ground access gateway to the second terminal device.

[0133] Optionally, the interface module is further configured to receive third information, the third information being used to indicate that a path state between the first network element and the second network element changes.

[0134] 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, the interface module is configured to send, in response to the third information, a path available indication.

[0135] 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, the interface module is configured to send, in response to the third information, a path unavailable indication.

[0136] Optionally, the first request message further includes an IP address of the second terminal device and an IP address of the ground access gateway, and the interface module is further configured to send a third split rule, the third split rule being used to instruct the second network element to send a third data packet from the session anchor to the second terminal device, the third data packet being a data packet sent by the ground access gateway to the second terminal device, the ground access gateway being deployed in a second ground network, the session anchor being deployed in a first ground network, and the ground access gateway and the second network element transmitting the third data packet through the session anchor.

[0137] The seventh aspect of the present application provides a communication device, comprising:

[0138] a processing module configured to acquire identification information of a third network element, the third network element being deployed in a first non-terrestrial network device;

[0139] an interface module configured to send the identification information of the third network element, the identification information of the third network element being used to acquire a transmission path between a third terminal device and a fourth terminal device, and the third network element providing service for the third terminal device;

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

[0141] Optionally, the interface module is further configured to send a third request message, the third request message comprising identification information of the third terminal device.

[0142] the interface module is further configured to receive a fourth response message, the fourth response message being a response message of the third request message, and the fourth response message comprising the identification information of the third network element.

[0143] Optionally, the third response message comprises indication information of a first path and / or indication information of a second path, the first path being a path between the third terminal device and the fourth terminal device through the third network element and a fourth network element, the second path being a path between the third terminal device and the fourth terminal device through a session anchor or a ground access gateway, the fourth network element providing service for the fourth terminal device, the session anchor being deployed in a first ground network, and the ground access gateway being deployed in a second ground network, wherein the session anchor comprises a session anchor providing service for the third terminal device and a session anchor providing service for the fourth terminal device, and the ground access gateway comprises a ground access gateway providing service for the third terminal device and a ground access gateway providing service for the fourth terminal device.

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

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

[0146] The call signaling comprises any one of the following: an IP address of the fourth terminal device, an IP address of a ground access gateway, wherein the ground access gateway is a ground access gateway serving the third terminal device, an IP address of the third network element.

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

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

[0149] Case C: When the fourth response message indicates the second path, and the second path is a path between the third terminal device and the fourth terminal device through a session anchor point, the IP address of the fourth terminal device is included in the call signaling. In this case, the third terminal device sends the session data packet to the fourth terminal device directly through the IP address of the fourth terminal device.

[0150] Case D: When the fourth response message indicates the second path, and the second path is a path between the third terminal device and the fourth terminal device through a ground access gateway, the IP address of the ground access gateway is included in the call signaling, wherein the ground access gateway is a ground access gateway serving the third terminal device. In this case, the third terminal device sends the session data packet to the fourth terminal device through the ground access gateway serving the third terminal device.

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

[0152] Optionally, the interface module is further configured to receive third information, the third information being used to indicate that a path state of the first path or the second path changes;

[0153] The interface module is further configured to send fourth information, the fourth information being used to indicate that the first path is switched to the second path, or used to indicate that the second path is switched to the first path.

[0154] Optionally, when the fourth information is used to instruct to switch the first path to the second path, and the second path is a path between the third terminal device and the fourth terminal device through a ground access gateway, the fourth information comprises an IP address of the ground access gateway, the ground access gateway is a ground access gateway serving the third terminal device, and the ground access gateway is deployed in the second ground network.

[0155] Or, when the fourth information is used to instruct to switch the first path to the second path, and the second path is a path between the third terminal device and the fourth terminal device through a session anchor, the fourth information comprises an IP address of the third terminal device.

[0156] Or, when the fourth information instructs to switch the second path to the first path, and the third network element is a user plane function network element, the fourth information comprises tunnel information of the third network element and an IP address of the third terminal device, and the third network element serves the third terminal device.

[0157] Or, when the fourth information instructs to switch the second path to the first path, and the third network element and the fourth network element are both access gateways, the fourth information comprises an IP address of the third network element.

[0158] Optionally, the interface module is further configured to send second indication information, the second indication information comprising address information required by the third terminal device for sending session data to the fourth terminal device through a target path, the target path being the first path or the second path.

[0159] When the target path is the above case A, the second indication information is used to instruct the third terminal device to send session data packets to the fourth terminal device directly through an IP address of the fourth terminal device.

[0160] When the target path is the above case B, the second indication information is used to instruct the third terminal device to send session data packets to the fourth terminal device through the third network element, and then send the session data packets to the fourth terminal device by the third network element.

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

[0162] When the target path is the above case D, the second indication information is used to instruct the third terminal device to send session data packets to the fourth terminal device through a ground access gateway serving the third terminal device, and then send the session data packets to the fourth terminal device by the ground access gateway.

[0163] Optionally, the interface module is further configured to send fifth information in the path switching process, the fifth information comprising service flow information between the third terminal device and a ground access gateway.

[0164] Optionally, the call signaling further comprises third indication information, the third indication information being used to instruct the third terminal device to use the first path or the second path to transmit data according to path states of the first path and / or the second path.

[0165] Optionally, the call signaling further comprises a path selection policy, the path selection policy comprising one or more of an initial path indication, a path priority, a path with a low latency, a path with a low packet loss rate, a path latency threshold, and a path packet loss rate threshold.

[0166] Optionally, the call signaling further comprises fourth indication information, the fourth indication information being used to instruct the third terminal device to perform path monitoring to obtain path states of the first path and / or the second path.

[0167] Optionally, the third network element is an access gateway, the third response message comprises information of the third path and / or information of a fourth path, the information of the third path comprises an IP address of a 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 for a fourth terminal device, the information of the fourth path comprises an IP address of a terrestrial access gateway, the terrestrial access gateway is deployed on a second terrestrial network, the third path is a path between the third terminal device and the fourth terminal device through the third network element and the fourth network element, and the fourth path is a path between the third terminal device and the fourth terminal device through the third network element and the terrestrial access gateway.

[0168] Optionally, the interface module is further configured to send fifth indication information, the fifth indication information being used to instruct the third network element to use the third path or the fourth path to transmit data according to path states of the third path and / or the fourth path.

[0169] Optionally, the interface module is further configured to send a path selection policy, the path selection policy comprising one or more of an initial path indication, a path priority, a path with a low latency, a path with a low packet loss rate, a path latency threshold, and a path packet loss rate threshold.

[0170] The interface module is further configured to send sixth indication information, the sixth indication information being used to instruct the third network element to monitor path states of the third path and / or the fourth path.

[0171] Optionally, when the third network element and the fourth network element are both access gateways, the third response message comprises path state information, the processing module is further configured to determine a transmission path based on the path state information, the path state information being determined based on identification information of the third network element, the path state information being used to instruct a path state between the third network element and the fourth network element, and the fourth network element providing services for the fourth terminal device.

[0172] An eighth aspect of the present application provides a communication device, comprising:

[0173] an interface module, configured to receive identification information of a third network element, the identification information of the third network element being used to obtain a transmission path between the third terminal device and a fourth terminal device, the third network element providing a service for the third terminal device, the third network element being a user plane function network element or an access gateway, and the third network element being deployed on a first non-terrestrial network device;

[0174] a processing module, configured to generate a third response message;

[0175] the interface module is further configured to send the third response message, and the third response message is used to indicate the transmission path between the third terminal device and the fourth terminal device.

[0176] Optionally, the interface module is further configured to send a second request message, and the second request message includes identification information of the third network device;

[0177] the interface module is further configured to receive a fourth response message, the fourth response message being a response message of the second request message, and the fourth response message is used to indicate a path establishment state between the third network element and a fourth network element, the fourth network element providing a service for the fourth terminal device, and the fourth network element being deployed on a second non-terrestrial network device;

[0178] the processing module is further configured to determine the transmission path between the third terminal device and the fourth terminal device according to the path establishment state between the third network element and the network element.

[0179] Optionally, the third response message includes indication information of a first path or indication information of a second path, the first path being a path between the third terminal device and the fourth terminal device through the third network element and the fourth network element, the second path being a path between the third terminal device and the fourth terminal device through a session anchor or a ground access gateway, the fourth network element providing a service for the fourth terminal device, and the session anchor being deployed on a first ground network and the ground access gateway being deployed on a second ground network.

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

[0181] Or, if the path establishment state between the third network element and the fourth network element is a failed establishment state, the second response message includes the indication information of the second path.

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

[0183] Optionally, the interface module is further configured to send the call signaling, the call signaling comprising an IP address of the third terminal device and / or an IP address of the ground access gateway; or, when the fourth network element is an access gateway, the call signaling comprising an IP address of the fourth network element and / or an IP address of the ground access gateway.

[0184] Optionally, the interface module is further configured to receive third information, the third information being used to indicate that a path state of the first path or the second path changes.

[0185] The interface module is further configured to send fourth information, the fourth information being used to indicate that the first path is switched to the second path or used to indicate that the second path is switched to the first path.

[0186] Optionally, when the fourth information is used to indicate that the first path is switched to the second path, the fourth information comprises an IP address of the ground access gateway, the ground access gateway being deployed in the second ground network.

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

[0188] Or, when the fourth information indicates that the second path is switched to the first path and the third network element and the fourth network element are both access gateways, the fourth information comprises an IP address of the fourth network element.

[0189] Optionally, the interface module is further configured to send second indication information, the second indication information being used to indicate that the fourth terminal device switches the first path to the second path or switches the second path to the first path.

[0190] Optionally, the interface module is further configured to send fifth information, the fifth information comprising service flow information between the fourth terminal device and the ground access gateway.

[0191] Optionally, the call signaling further comprises third indication information, the third indication information being used to indicate that the fourth terminal device uses the first path or the second path to transmit data according to a path state of the first path and / or the second path.

[0192] Optionally, the call signaling further comprises a path selection policy, the path selection policy comprising one or more of an initial path indication, a path priority, a path with a low selection delay, a path with a low packet loss rate, a path delay threshold value and a path packet loss rate threshold value.

[0193] Optionally, the call signaling further comprises fourth indication information, the fourth indication information being used to indicate that the fourth terminal device performs path monitoring to obtain a path state of the first path and / or the second path.

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

[0195] Optionally, the interface module is further configured to send fifth indication information, the fifth indication information being used to instruct the fourth network element to use the third path or the fourth path to transmit data according to a path state of the third path and / or the fourth path.

[0196] Optionally, the interface module is further configured to send path selection policy, the path selection policy comprising one or more of initial path indication, path priority, selecting a path with low latency, selecting a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0197] The interface module is further configured to send sixth indication information, the sixth indication information being used to instruct the fourth network element to monitor a path state of the third path and / or the fourth path.

[0198] Optionally, the processing module is further configured to determine a transmission path based on path state information, the path state information being determined based on the identification information of the third network element, the path state information being used to indicate a path state between the third network element and the fourth network element, and the fourth network element providing services for the fourth terminal device.

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

[0200] The processing module is configured to determine path state information, the path state information being used to indicate a path state between the third network element and the fourth network element, the third network element being deployed in the first non-terrestrial network device, the fourth network element being deployed in the second non-terrestrial network device, the third network element and the fourth network element both being user plane function network elements, or the third network element and the fourth network element both being access gateways.

[0201] The interface module is configured to transmit the path state information.

[0202] The processing module is further configured to determine a transmission path between the third terminal device and the fourth terminal device according to the path state information, the first network element providing services for the first terminal device, and the second network element providing services for the second terminal device.

[0203] Optionally, the transmission path comprises: a first path and / or a second path, the first path being a 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 being a path between the third terminal device and the fourth terminal device through the session anchor or the ground access gateway, the session anchor being deployed in the first ground network, or the ground access gateway being deployed in the second ground network.

[0204] Optionally, when the second path is a path between the third terminal device and the fourth terminal device through the session anchor, the interface module is further configured to receive a first offloading rule and / or a second offloading rule, the first offloading rule being used for indicating the first path, and the second offloading rule being used for indicating the second path.

[0205] Optionally, the interface module is further configured to receive first indication information, the first indication information being used for indicating that the first offloading rule or the second offloading rule is used according to the path state information.

[0206] The processing module is further configured to determine the transmission path of the first data packet according to the first offloading rule or the second offloading rule according to the path state information in response to the first indication information.

[0207] Optionally, the processing module is specifically configured to determine that the transmission path is the first path if the path state of the first path is an available state.

[0208] Or, the processing module is specifically configured to determine that the transmission path is the second path if the path state of the first path is an unavailable state.

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

[0210] Optionally, when the second path is a path between the third terminal device and the fourth terminal device through the ground access gateway, the interface module is further configured to receive a path configuration message, the path configuration message comprising an IP address of the third network element and / or an IP address of the ground access gateway, the IP address of the third network element being used for indicating the first path or the third path, and the IP address of the ground access gateway being used for indicating the second path or the fourth path.

[0211] Optionally, the interface module is further configured to receive fifth indication information, the fifth indication information being used for indicating that the third network element uses the third path or the fourth path to transmit data according to the path state of the third path and / or the fourth path.

[0212] Optionally, the interface module is further configured to receive a path selection policy, the path selection policy comprising one or more of an initial path indication, a path priority, a path with a low latency, a path with a low packet loss rate, a path latency threshold, and a path packet loss rate threshold.

[0213] Optionally, the interface module is specifically configured to receive a path state subscription request, the path state subscription request being used to request sending of a path state notification message when a path state between the fourth network element and any network element of the at least one network element changes.

[0214] The interface module is specifically configured to send the path state notification message, the path state notification message being used to indicate the path state between the fourth network element and any network element of the at least one network element, and the path state notification message comprising path state information.

[0215] Optionally, the interface module is further configured to receive a query request message, the query request message comprising identification information of the third network element, and the query request message being used to request querying of a path state between the third network element and the fourth network element.

[0216] The interface module is further configured to send a first response message, the first response message being a response message of the query request message, and the first response message being used to indicate the path state information.

[0217] Optionally, the interface module is further configured to send first information, the first information being used to indicate that a path state between the first network element and the second network element changes.

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

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

[0220] The processing module is configured to determine a transmission path of the second data packet according to the indication information of the first path and the indication information of the second path.

[0221] Optionally, the indication information of the first path comprises an IP address of a third network element, the indication information of the second path comprises an IP address of the ground access gateway, and the third network element provides services for the third terminal device.

[0222] Optionally, the interface module is further configured to receive third indication information, the third indication information being used to indicate that the path of the second data packet is determined according to a state of the first path or the second path.

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

[0224] Optionally, the interface module is further configured to receive a path selection policy, the path selection policy comprising one or more of the initial path indication, the path priority, the path with lower latency, the path with lower packet loss rate, the path latency threshold, and the path packet loss rate threshold.

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

[0226] The eleventh aspect of the present application provides a communication apparatus, which can be the SMF network element, the first P-CSCF, the second P-CSCF, the fourth network element, or the third terminal device, can also be a component (for example, a processor, a chip, or a chip system) applied to the SMF network element, the first P-CSCF, the second P-CSCF, the fourth network element, or the third terminal device, and can also be a logic module or software capable of realizing all or part of the functions of the SMF network element, the first P-CSCF, the second P-CSCF, the fourth network element, or the third terminal device. The communication apparatus comprises:

[0227] The processor is configured to execute a program, so that the communication apparatus performs the method according to any one of the first aspect to the fifth aspect and any one of the possible implementation manners thereof.

[0228] Optionally, the communication apparatus further comprises a memory, and the processor is coupled to the memory; and the memory is configured to store the program.

[0229] The twelfth aspect of the present application provides a chip or a chip system, which comprises at least one processor and a communication interface, the communication interface and the at least one processor are interconnected through a line, and the at least one processor is configured to run a computer program or an instruction to perform the communication method described in any one of the possible implementation manners of any one of the first aspect to the fifth aspect.

[0230] The communication interface in the chip can be an input / output interface, a pin, or a circuit.

[0231] In a possible implementation, the chip or the chip system described in the present application further comprises at least one memory, and the at least one memory stores instructions. The memory can be a storage unit inside the chip, for example, a register, a cache, or the like, or can be a storage unit of the chip, for example, a read-only memory, a random access memory, or the like.

[0232] The thirteenth aspect of the present application provides a communication system, comprising a communication device performing any one of the first aspect to the fifth aspect and any possible implementation thereof.

[0233] The fourteenth aspect of the present application provides a computer readable storage medium comprising instructions which, when executed on a computer, cause the computer to perform the method of the first aspect, or cause the computer to perform the method of the second aspect, or cause the computer to perform the method of the third aspect, or cause the computer to perform the method of the fourth aspect, or cause the computer to perform the method of the fifth aspect.

[0234] The fifteenth aspect of the present application provides a computer program product comprising instructions which, when executed on a computer, cause the computer to perform the method of the first aspect, or cause the computer to perform the method of the second aspect, or cause the computer to perform the method of the third aspect, or cause the computer to perform the method of the fourth aspect, or cause the computer to perform the method of the fifth aspect. BRIEF DESCRIPTION OF DRAWINGS

[0235] FIG. 1 is a ground network architecture diagram in the embodiment of the present application;

[0236] FIG. 2 is a non-ground network architecture diagram in the embodiment of the present application;

[0237] FIG. 3 is one possible application scenario of the communication method in the embodiment of the present application;

[0238] FIG. 4 is another possible application scenario of the communication method in the embodiment of the present application;

[0239] FIG. 5 is an embodiment schematic diagram of the communication method in the embodiment of the present application;

[0240] FIG. 6 is another embodiment schematic diagram of the communication method in the embodiment of the present application;

[0241] FIG. 7 is another embodiment schematic diagram of the communication method in the embodiment of the present application;

[0242] FIG. 8 is another embodiment schematic diagram of the communication method in the embodiment of the present application;

[0243] FIG. 9 is another embodiment schematic diagram of the communication method in the embodiment of the present application;

[0244] FIG. 10 is another embodiment schematic diagram of the communication method in the embodiment of the present application;

[0245] FIG. 11 is another embodiment schematic diagram of the communication method in the embodiment of the present application;

[0246] Fig. 12 is a schematic diagram of one embodiment of a communication device in the present application;

[0247] Fig. 13 is a schematic diagram of another embodiment of a communication device in the present application;

[0248] Fig. 14 is a schematic diagram of another embodiment of a communication device in the present application;

[0249] Fig. 15 is a schematic diagram of another embodiment of a communication device in the present application;

[0250] Fig. 16 is a schematic diagram of another embodiment of a communication device in the present application;

[0251] Fig. 17 is a schematic diagram of another embodiment of a communication device in the present application;

[0252] Fig. 18 is a schematic diagram of another embodiment of a communication device in the present application. DETAILED DESCRIPTION

[0253] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0254] The description of "one embodiment", "some embodiments", and the like in the present application means that the specific features, structures, or characteristics described in connection with the embodiment are included in one or more embodiments of the present application. Therefore, the statements "in one embodiment", "in some embodiments", "in other some embodiments", "in other some embodiments", and the like appearing in different places in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "include", "contain", "have", and their variants mean "include but are not limited to", unless otherwise specifically emphasized.

[0255] In the description of the present application, unless otherwise specified, " / " means "or", for example, A / B can mean A or B. "And / or" in this article is only a description of the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean: A alone, A and B exist at the same time, and B alone. In addition, "at least one" means one or more, and "multiple" means two or more. "At least one of the following" or similar expressions means any combination of the items, including any combination of single or multiple items. For example, at least one of a, b, or c, can mean: a, b, c; a and b; a and c; b and c; or a and b and c. Where a, b, c can be single or multiple.

[0256] It can be understood that in this application, "indication" can include direct indication, indirect indication, display indication, and implicit indication. When describing certain indication information for indicating A, it can be understood that the indication information carries A, directly indicates A, or indirectly indicates A.

[0257] The terms "first", "second", and the like in the specification, claims, and drawings of the present application are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged under appropriate circumstances, which is only a distinguishing way used in describing the same attribute objects in the embodiments of the present application. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, so that the process, method, system, product or equipment containing a series of units does not have to be limited to those units, but can include other units not clearly listed or inherent to these processes, methods, products or equipment.

[0258] In the embodiments of the present application, "when... step A is performed" and "if... step A is performed" can mean that step A is performed under certain conditions, and do not limit the timing of step A. "When... B includes C" and "if... B includes C" can mean that the content of B includes / carries C under certain conditions.

[0259] First, some technical terms involved in the embodiments of the present application are introduced.

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

[0261] The P-CSCF network element is a key functional entity in the Internet Protocol (IP) Multimedia Subsystem (IMS). It is the unified entry point of the IMS visited network, and all session control messages initiated by IMS terminals and terminated by IMS terminals pass through the P-CSCF network element. It is similar to a proxy server, responsible for receiving service requests and forwarding these service requests within the IMS subnet. In addition, the P-CSCF network element is responsible for user authentication, signaling compression, roaming control, quality of service (QoS) policy decision, and other functions. When a terminal device needs to establish a session with another terminal device, the terminal device sends a session initiation protocol (SIP) signaling, i.e., SIP Invite, to the P-CSCF network element. The P-CSCF network element is responsible for receiving the SIP Invite request and forwarding it to the corresponding IMS network element for processing according to the content and target address of the request.

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

[0263] The SMF is a functional unit in the service-based architecture (SBA) of the 5th generation mobile communication technology (5G), mainly responsible for session management functions. It is an important part of the 5G core network (5GC) and closely cooperates with the user plane function (UPF) and other network elements of the control plane function to provide high-quality communication services for users. One of the functions of the SMF is to maintain the data transmission tunnel between the terminal device and the UPF, ensuring the correct routing and transmission of data packets.

[0264] 3) Access Gateway (AGW):

[0265] The AGW, i.e., the IMS AGW, is a network element in the IMS, acting as a media gateway to transmit media data packets between different terminal devices.

[0266] The following are some key functions and features of the 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 perform voice or video transcoding to adapt to different devices and network requirements.

[0272] Security: AGW supports encryption and authentication mechanisms to ensure the security of communication.

[0273] Interoperability: AGW supports interoperability with various non-IMS networks, including fixed telephone networks and mobile telephone 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] Charging and recharge: AGW can interact with the charging system to provide charging and recharge services for non-IMS devices.

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

[0278] Inter-satellite link, also known as inter-orbital link or crosslink, refers to the link used for communication between satellites. This link allows satellites to directly transmit data and signals to each other without the need for ground network equipment to relay, thereby improving the efficiency and speed of data transmission and reducing communication delay. According to the orbital types of the corresponding satellites at both ends, inter-satellite links can be divided into inter-satellite links between the same orbital types and inter-satellite links between different orbital types. Inter-satellite links between the same orbital types include links between geostationary earth orbit (GEO) satellites, links between low earth orbit (LEO) satellites, etc. Inter-satellite links between different orbital types include links between GEO satellites and LEO satellites, links between LEO satellites and medium earth orbit (MEO) satellites, etc.

[0279] Please refer to FIG. 1, the ground network architecture based on which the communication method in the embodiment of the present application is described as follows:

[0280] FIG. 1 is a possible, non-limiting system diagram. As shown in FIG. 1, the communication system 10 includes a radio access network (RAN) 100, a core network (CN) 200, and the Internet 300. The RAN 100 includes at least one RAN node (e.g., 110a and 110b in FIG. 1, collectively referred to as 110) and at least one terminal (e.g., 120a-120j in FIG. 1, collectively referred to as 120). Other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in FIG. 1), etc., can also be included in the RAN 100. The terminal 120 is connected to the RAN node 110 in a wireless manner. The RAN node 110 is connected to the core network 200 in a wireless or wired manner. The core network device in the core network 200 and the RAN node 110 in the RAN 100 can be different physical devices respectively, or can be the same physical device integrated with the logical functions of the core network and the logical functions of the radio access network.

[0281] The RAN 100 can be a 3rd generation partnership project (3GPP) related cellular system, e.g., a 4th generation mobile communication technology (4G), a 5th generation mobile communication technology (5G) mobile communication system, or a future mobile communication system. The RAN 100 can also be an open-radio access network (ORAN), a cloud-radio access network (CRAN), or a wireless fidelity (WiFi) system. The RAN 100 can also be a communication system in which two or more of the above systems are fused.

[0282] The RAN nodes 110, which can also be referred to as access network devices, RAN entities, or access nodes, etc., form part of the communication system 10 and are configured to facilitate wireless access to the communication system 10 by terminals. The RAN nodes 110 in the communication system 10 can be the same type of node or different types of nodes. The roles of the RAN nodes 110 and the terminals 120 are relative, in some scenarios, e.g., the network element 120i in Figure 1 can be a helicopter or a drone, which can be configured to move as a mobile base station, to the terminals 120j accessing the RAN 100 via the network element 120i, the network element 120i is a base station; but to the base station 110a, the network element 120i is a terminal. The RAN nodes 110 and the terminals 120 are sometimes referred to as communication apparatuses, e.g., the network elements 110a and 110b in Figure 1 can be understood as communication apparatuses with base station functionality, and the network elements 120a-120j can be understood as communication apparatuses with terminal functionality.

[0283] In a possible scenario, the access network device includes, but is not limited to, an evolved Node B (eNB), a radio network controller (RNC), a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (for example, a home evolved Node B, or home Node B, HNB), a baseband unit (BBU), an access point (AP) in a wireless fidelity (WiFi) system, a macro base station, a micro base station, a wireless relay node, a donor node, a wireless controller in a CRAN scenario, a wireless backhaul node, a transmission point (TP), or a transmission and reception point (TRP), and the like, and can also be an access network device in a 5G mobile communication system. For example, a next generation Node B (gNB), a TRP, or a TP in an NR system; or one or a group (including multiple antenna panels) of antenna panels of a base station in a 5G mobile communication system; or the access network device can also be a network node constituting a gNB or a transmission point. For example, a centralized unit (CU), a distributed unit (DU), a centralized unit control plane (CU-CP), a centralized unit user plane (CU-UP), or a radio unit (RU), and the like. The CU and the DU can be separately arranged, or can be included in the same network element, for example, a BBU. The RU can be included in a radio frequency device or a radio frequency unit. For example, in a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). Or the access network device can also be a server, a wearable device, a vehicle or a vehicle-mounted device, and the like. For example, the access network device in V2X technology can be a road side unit (RSU). It should be understood that the above-mentioned TRP can be a device or module located at the network side of the above-mentioned communication system and having corresponding communication functions.The TRP is usually provided with a communication module, circuit or chip that performs a corresponding communication function. The TRP can also be configured with program instructions for the corresponding communication function.

[0284] It should be noted that in different systems, the CU (or CU-CP and CU-UP), DU or RU can also have different names, but those skilled in the art can understand their meanings. For example, in an open radio access network (ORAN) system, the CU can also be referred to as an open centralized unit (O-CU) or an open CU, the DU can also be referred to as an open distributed unit (O-DU), the CU-CP can also be referred to as an open centralized unit control plane (O-CU-CP), the CU-UP can also be referred to as an open centralized unit user plane (O-CU-UP), and the RU can also be referred to as an open radio unit (O-RU). The specific application is not limited. Any of the CU, CU-CP, CU-UP, DU and RU in the present application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[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 device in the present application can be one or more network elements in Table 1 above.

[0288] The architecture of the CU and the DU of the access network device will be introduced below. The access network device includes at least one CU and at least one DU. Optionally, the access network device also includes at least one RU.

[0289] The following is introduced by taking an access network device including a CU and a DU as an example. The CU has part of the function of the core network, and the CU can include a CU-CP and a CU-UP. The CU and the DU can be configured according to the protocol layer function of the wireless network they implement. For example, the CU is configured to implement the function of the packet data convergence protocol (PDCP) layer and the protocol layer above (for example, the function of the RRC layer and / or the SDAP layer). The DU is configured to implement the function of the protocol layer below the PDCP layer (for example, the function of the RLC layer, the MAC layer, and / or the physical (PHY) layer). For another example, the CU is configured to implement the function of the protocol layer above the PDCP layer (for example, the function of the RRC layer and / or the SDAP layer), and the DU is configured to implement the function of the protocol layer below the PDCP layer (for example, the function of the RLC layer, the MAC layer, and / or the PHY layer).

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

[0291] The CU-CP can interact with a network element in the core network for implementing the control plane function. The network element in the core network for implementing the control plane function can be an access and mobility function network element, for example, an AMF in a 5G system. The AMF is used to be responsible for the mobility management in the mobile network, such as the location update of the terminal device, the registration network of the terminal device, the handover of the terminal device, and the like.

[0292] The CU-UP can interact with a network element in the core network for implementing the user plane function. The network element in the core network for implementing the user plane function, for example, a user function (UPF) in a 5G system, is used to be responsible for the forwarding and receiving of data in the terminal device.

[0293] The configuration of the CU and the DU above is merely an example, and the CU and the DU can be configured to have functions as needed. For example, the CU or the DU can be configured to have functions of more protocol layers, or the CU or the DU can be configured to have partial processing functions of the protocol layers. For example, partial functions of the RLC layer and functions of protocol layers above the RLC layer are arranged in the CU, and the remaining functions of the RLC layer and functions of protocol layers below the RLC layer are arranged in the DU. For another example, the functions of the CU or the DU can be divided according to a service type or other system requirements. For example, according to a delay, functions that need to meet a relatively low delay requirement are arranged in the DU, and functions that do not need to meet the delay requirement are arranged in the CU.

[0294] The DU and the RU can cooperate to jointly implement the functions of the PHY layer. One DU can be connected to one or more RUs. The functions of the DU and the RU can be configured in multiple ways according to design. For example, the DU is configured to implement baseband functions, and the RU is configured to implement intermediate radio frequency functions. For another example, the DU is configured to implement high-layer functions in the PHY layer, and the RU is configured to implement low-layer functions in the PHY layer or implement the low-layer functions and radio frequency functions. The high-layer functions in the PHY layer can include a part of functions of the PHY layer that are closer to the MAC layer, and the low-layer functions in the PHY layer can include another part of functions of the PHY layer that are closer to the intermediate radio frequency side.

[0295] It should be noted that the access network device can be a device or apparatus with a chip, or a device or apparatus integrated with a circuit, or a chip, a chip system, a module, or a control unit in the foregoing devices or apparatus, and the specific application is not limited. It should be noted that in the present application, when referring to the access network device, it can refer to the access network device itself, or refer to a chip, a functional module, or an integrated circuit in the access network device that completes the method provided in the present application, and the specific application is not limited.

[0296] In another possible scenario, multiple RAN nodes cooperate to assist a terminal to implement wireless access, and different RAN nodes respectively implement part of functions of a base station. For example, a RAN node can be a central unit (CU), a distributed unit (DU), a CU-CP, a CU-UP, or a radio unit (RU), etc. The CU and the DU can be separately configured, or can also be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, such as a remote radio unit (RRU), an active antenna processing unit (AAU), or a remote radio head (RRH).

[0297] In different systems, the CU (or CU-CP and CU-UP), DU or RU can also have different names, but those skilled in the art can understand their meanings. For example, in an ORAN system, the CU can also be referred to as an O-CU (open CU), the DU can also be referred to as an O-DU, the CU-CP can also be referred to as an O-CU-CP, the CU-UP can also be referred to as an O-CU-UP, and the RU can also be referred to as an O-RU. For the convenience of description, the CU, CU-CP, CU-UP, DU and RU are taken as examples for description in this application. Any one of the CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0298] A terminal can be a device or module with corresponding communication functions and can access the above-mentioned communication system. The terminal can also be referred to as a terminal device, user equipment (UE), mobile station, mobile terminal, etc. The terminal 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, remote medical treatment, smart grid, smart home, smart office, smart wear, smart transportation, smart city, etc. The terminal can be a mobile phone, tablet computer, computer with wireless transceiver function, wearable device, vehicle, unmanned aerial vehicle, helicopter, airplane, ship, robot, mechanical arm, smart home device, transport vehicle with wireless communication function, communication module, etc. Embodiments of the present application do not limit the device form of the terminal. The terminal usually has a communication module, circuit or chip for performing corresponding communication functions. The terminal can also be configured with program instructions for performing corresponding communication functions.

[0299] In embodiments of the present application, the RAN node can be deployed on a satellite. For example, the base station can be deployed entirely on a satellite. The core network network device can also be deployed on a satellite, for example, the core network user plane network element can be deployed on a satellite to support direct exchange between terminals through a satellite, and communication without landing. Part of the control plane network element of the core network can also be deployed on a satellite, for example, the mobility management network element and the session management network element can be deployed on a satellite to support emergency rescue services in disaster scenarios without ground network. In addition, the IMS AGW can also be deployed on a satellite, and when the communication between the terminals is directly exchanged through the satellite, the deployment of the IMS AGW on the satellite can support the charging function of the call.

[0300] Please refer to FIG. 2, the following describes the non-terrestrial network (NTN) architecture based on which the communication method in embodiments of the present application is based:

[0301] The ground mobile terminal accesses the new radio access network, and the network device is deployed on a satellite and connected to the ground core network through a wireless link. At the same time, there can be an inter-satellite link between satellites to complete the signaling interaction and user data transmission between network devices. The various network elements in FIG. 2 and their interfaces are described as follows:

[0302] Terminal: a mobile device supporting new radio, typically such as a mobile phone, a pad, and the like. The terminal can access a satellite network through a radio and initiate a call, access the Internet, and the like.

[0303] Network device: mainly providing wireless access services, scheduling wireless resources for access terminals, providing reliable wireless transmission protocols and data encryption protocols, and the like. In addition to the wireless base station, the network device deployed on the satellite also includes a user plane network element function and an IMS AGW function. The network device deployed on the satellite is referred to as an NTN node.

[0304] Core network: user access control, mobility management, session management, user security authentication, charging, and the like. It is composed of multiple functional units and can be divided into control plane and data plane functional entities. An access and mobility management unit (AMF) is responsible for user access management, security authentication, and mobility management. A user plane unit (UPF) is responsible for managing user plane data transmission, traffic statistics, and the like. The user plane network element can be deployed on a satellite or on the ground. In the embodiments of the present application, the anchor user plane network element is deployed on the ground, and the anchor user plane network element is the anchor point of the IP address of the terminal device. In the 5G system, the anchor user plane network element is a session anchor (PSA) and is responsible for the allocation of the IP address of the terminal device.

[0305] Ground station: responsible for forwarding signaling and service data between the satellite base station and the core network. The ground station is a network device deployed on the ground. The ground station can be a network device, a component (such as a processor, a chip, or a chip system, and the like) applied to the network device, or a logic module or software capable of realizing all or part of the functions of the network device.

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

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

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

[0309] The terminal device in FIG. 2 can be located in the beam or cell coverage range of the network device. Among them, the terminal device can perform air interface communication with the network device through uplink (UL) or downlink (DL). For example, the terminal device can send uplink data to the network device through the physical uplink shared channel (PUSCH) in the UL direction; the network device can send downlink data to the terminal device through the physical downlink shared channel (PDSCH) in the DL direction. The terminal device can be a terminal device supporting new radio, which can access the network device through the air interface and initiate calls, Internet access, and other services. Illustratively, the network device can be a RAN device (or RAN payload) carried on an NTN device (such as a satellite). When the RAN device is carried on the NTN device, the RAN device moves synchronously with the NTN device. In addition, the communication link between the RAN device carried on the NTN device and the terminal device can be referred to as a service link. When multiple RAN devices are included in the communication system, the RAN device carried on the NTN device can communicate with the RAN device through an Xn interface. In actual applications, the network device can also be a RAN device distributed based on a DU and carried on an NTN device. The specific details are not limited here. The terminal device and network device shown in FIG. 2 can refer to the description of the terminal device and network device in FIG. 1, and the specific details are not repeated here.

[0310] The NTN device described above can be a satellite, a drone, or other aircraft. Illustratively, the NTN device can 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 flight system platform, a high-altitude platform station (HAPS), a hot air balloon, or a high-orbit satellite, and the like. The specific details are not limited here. The embodiments of the present application take the NTN device as a satellite for illustration.

[0311] Among them, the low-orbit and medium-orbit satellites can have their own motion trajectories, and generally provide communication for a fixed area by cooperation of multiple satellites. The high-orbit satellite is generally in a stationary state, and one or a few high-orbit satellites provide communication for a fixed area.

[0312] In addition, the embodiments of the present application can also be applied to other future-oriented communication technologies. The network architecture and service scenarios described in the present application are for more clearly illustrating the technical solutions of the present application, and do not constitute a limitation on the technical solutions provided by the present application. Those skilled in the art can know that, with the evolution of network architecture and the appearance of new service scenarios, the technical solutions provided by the present application are also applicable to similar technical problems.

[0313] FIG. 3 shows a possible application scenario of an embodiment of the present application. In this scenario, the UPF network element is deployed on an NTN device, for example, the UPF network element is deployed on a satellite. For example, the satellite accessed by UE1 is referred to as the first satellite, the satellite accessed by UE2 is referred to as the second satellite, and the inter-satellite link between the first satellite and the second satellite is ISL1. UE1 communicates with UE2 through the satellite-borne UPF1 deployed on the first satellite, the ISL1 between the first satellite and the second satellite, and the satellite-borne UPF2 deployed on the second satellite. The satellite-borne UPF1 sends the data packet from UE1 to the satellite-borne UPF2 through the ISL1, and the satellite-borne UPF2 sends the data packet to UE2.

[0314] FIG. 4 shows another possible application scenario of an embodiment of the present application. In this scenario, both the UPF network element and the AGW are deployed on an NTN device, for example, the UPF network element and the AGW are deployed on a satellite. For example, the satellite accessed by UE1 is referred to as the first satellite, the satellite accessed by UE2 is referred to as the second satellite, and the inter-satellite link between the first satellite and the second satellite is ISL1. UE1 communicates with UE2 through the satellite-borne AGW1 deployed on the first satellite, the ISL1 between the first satellite and the second satellite, and the satellite-borne AGW2 deployed on the second satellite. The satellite-borne AGW1 sends the data packet from UE1 to the satellite-borne AGW2 through the ISL1, and the satellite-borne AGW2 sends the data packet 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 the communication data packet between UE1 and UE2, i.e., offloading the uplink data packet to AGW1 and AGW2.

[0315] In the scenarios shown in FIG. 3 and FIG. 4, it is assumed in the description of subsequent embodiments that the core network control plane network elements, such as AMF, SMF, and the like, and the IMS control plane network elements, such as P-CSCF, S-CSCF, and the like, are deployed on the ground. However, the present application does not limit the deployment location of the core network control plane network elements and the IMS control plane network elements.

[0316] In the scenario shown in FIG. 3 and FIG. 4, UE1 is called the calling UE, UE2 is called the called UE, and the communication mode is called UE-SAT-UE communication, that is, the data packets are exchanged between UEs through an inter-satellite link without passing through ground equipment. When initiating a session, it is necessary to determine whether to enable UE-SAT-UE communication according to whether the calling UE and the called UE access through a satellite by the P-CSCF network element and / or the SMF network element. In actual applications, the inter-satellite link between satellites does not necessarily exist. For example, there are reverse orbits in a satellite network, and the satellites on the reverse orbit may be adjacent in space for a period of time, but the motion direction of the satellites is opposite. Due to the high relative speed between the satellites on the opposite orbits, it is difficult to establish an inter-satellite link. Therefore, the P-CSCF network element and / or the SMF network element need to obtain the state of the inter-satellite link between the first satellite and the second satellite first, so as to determine whether the first satellite and the second satellite support UE-SAT-UE communication. At present, the P-CSCF network element and / or the SMF network element need to query an external system, such as a satellite routing subsystem, to obtain whether the two satellites support direct communication through an inter-satellite link.

[0317] However, the interface between the P-CSCF network element or the SMF network element and the external system is difficult to standardize, and the equipment may be provided by different manufacturers. Therefore, it is difficult for the P-CSCF network element or the SMF network element to obtain the state of the inter-satellite link by querying the external system.

[0318] Based on this, the embodiments of the present application provide a communication method, a communication device, a communication system and a storage medium, which obtain the state of the inter-satellite path through the on-board UPF or the on-board AGW, so as to determine whether to enable UE-SAT-UE communication based on the state of the inter-satellite path, thereby avoiding the problem that the state of the inter-satellite path cannot be obtained due to the inability to query the external interface.

[0319] Referring to FIG. 5, FIG. 5 is a schematic diagram of a communication method provided in the embodiments of the present application. The method shown in FIG. 5 is interactively performed by the spaceborne UPF 1, the spaceborne UPF 2, the SMF 1, the SMF 2, the P-CSCF 1 and the P-CSCF 2. The method shown in FIG. 5 can be applied in the application scenario shown in FIG. 3, the spaceborne UPF 1 corresponds to the UPF on the first satellite, the spaceborne UPF 2 corresponds to the UPF on the second satellite, and the SMF 1, the SMF 2, the P-CSCF 1 and the P-CSCF 2 are network devices deployed on the ground. The spaceborne UPF 1 is a first network element, the spaceborne UPF 2 is a second network element, the SMF 2 is a first session management function network element, the SMF 1 is a second session management function network element, the P-CSCF 1 is a first proxy call session control function network element, and the P-CSCF 2 is a second proxy call session control function. In the embodiments of the present application, the P-CSCF 1 is a calling UE, that is, the proxy call session control function network element corresponding to the UE 1 shown in FIG. 3, and the P-CSCF 2 is a called UE corresponding to the proxy call session control function network element. Similarly, the spaceborne UPF 1 is the UPF accessed by the calling UE, and the spaceborne UPF 2 is the UPF accessed by the called UE, that is, the UE 2 shown in FIG. 3. The UE 1 is a first terminal device, the UE 2 is a second terminal device, the SMF 1 is responsible for managing the spaceborne UPF 1, and the SMF 2 is responsible for managing the spaceborne UPF 2. The method includes steps 501 to 510.

[0320] It should be noted that, in a possible implementation, the spaceborne UPF 1 and the adjacent spaceborne UPF can have a direct inter-satellite link, for example, the spaceborne UPF 1 and the adjacent spaceborne UPF are adjacent satellites on the same orbit or adjacent satellites on adjacent orbits, and the relative positions between them are relatively stable, so that a direct inter-satellite link can be established. In another possible implementation, the spaceborne UPF 1 and the adjacent spaceborne UPF can not have a direct inter-satellite link, but can be reached through an inter-satellite link through other satellites, for example, the spaceborne UPF 1 and the adjacent spaceborne UPF can be satellites on the same orbit, but at least one other satellite is interposed therebetween, and at this time, the inter-satellite path between the spaceborne UPF 1 and the adjacent spaceborne UPF is routed through the at least one other satellite. Alternatively, the orbits of the spaceborne UPF and the adjacent spaceborne UPF can be separated by at least one other orbit, and the routing between the spaceborne UPF 1 and the adjacent spaceborne UPF needs to be forwarded through the satellites on the at least one other satellite orbit. Alternatively, the relationship between the spaceborne UPF 1 and the adjacent spaceborne UPF can be a combination of the above two relationships, and the path between the spaceborne UPF 1 and the adjacent spaceborne UPF is forwarded through multiple satellites.

[0321] The low-orbit constellation is usually composed of multiple satellite orbits, multiple satellites on each satellite orbit, and each orbit layer (multiple satellite orbits with the same altitude and inclination form an orbit layer) is usually composed of hundreds or even thousands of satellites. In this scenario, it is usually difficult to support full-mesh routing between thousands of satellites and select the optimal path (or shortest path). In order to simplify the complexity of the algorithm, inter-satellite routing is usually configured between adjacent satellites, which means that inter-satellite routing is usually not supported when the satellites are too far apart (such as too many orbits apart or too many satellites apart in the direction of satellite movement). Even if adjacent satellites are reachable through inter-satellite links, the inter-satellite path delay is too large due to the excessive number of inter-satellite link hops. Based on this, the on-board UPF is configured with the addresses of adjacent on-board UPFs that can be reached through inter-satellite routing.

[0322] In order to monitor the path state between the on-board UPF1 and the adjacent on-board UPF, such as whether the on-board UPF1 and the adjacent on-board UPF are reachable, the link delay or link packet loss rate between the on-board UPF1 and the adjacent on-board UPF, etc., the on-board UPF1 can monitor the link state with the configured adjacent on-board UPF, for example, the link state can be monitored based on one-way active measurement protocol (OWAMP), two-way active measurement protocol (TWAMP), packet internet or inter-network groper (PING), etc. The monitoring can be periodic, i.e. every configured time period, so that when the path state changes, the on-board UPF can perceive the change of the path state through the periodic monitoring. The monitoring can also be bidirectional, i.e. the on-board UPF1 and the adjacent on-board UPF are configured with each other as the opposite end and independently start monitoring, and the on-board UPF1 and the adjacent on-board UPF can both obtain the path state through the monitoring of the local end. The on-board UPF2 is similar to the on-board UPF1, and details are not repeated here.

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

[0324] The P-CSCF 1 receives a SIP Invite request from the first terminal device, and the SIP Invite request includes identification information of the second terminal device. The identification information can be an IP address of the second terminal device, or other information used to identify the second terminal device, such as an MSISDN (mobile subscriber international ISDN / PSTN number), which is not limited here. The P-CSCF 1 sends a request message to the SMF (SMF 1) serving the first terminal device based on the SIP Invite request of the first terminal device. The P-CSCF 1 can send the request message after determining that the first terminal device accesses through the regenerative satellite. The request message includes the identification information of the first terminal device. The request message is also used to indicate the selection of the inter-satellite path. It should be noted that the P-CSCF and the SMF can not be directly interfaced, that is, the P-CSCF can send the above-mentioned request message to the SMF through other devices. For example, the P-CSCF 1 sends a request message to the PCF 1 serving the UE 1, and the PCF 1 sends the above-mentioned request message to the SMF 1. For example, in the embodiment, the request message sent by the P-CSCF 1 to the PCF 1 serving the UE 1 includes an indication of the selection of the inter-satellite path, and correspondingly, the request message sent by the PCF 1 to the SMF 1 includes indication information, which is used to instruct the SMF 1 to select the inter-satellite path.

[0325] The SMF 1 determines the satellite-borne UPF 1 accessed by the first terminal device as the UPF for the session of the first terminal device according to the request message. The SMF 1 can obtain the network element level tunnel information of the satellite-borne UPF 1. The network element level tunnel is a tunnel between the satellite-borne UPF 1 and other adjacent satellite-borne UPFs (such as the satellite-borne UPF 2). The network element level tunnel information can be allocated or configured on the satellite-borne UPF 1 by the satellite-borne UPF 1 and sent to the SMF 1 by the satellite-borne UPF 1, or configured on the SMF 1, and the SMF 1 obtains the tunnel information from the configuration information.

[0326] The request message only indicates the selection of the inter-satellite path, that is, the inter-satellite path is not established temporarily, so the SMF can only select the satellite-borne UPF 1 and obtain the network element level tunnel information of the satellite-borne UPF 1.

[0327] 502、The SMF 1 sends a response message to the P-CSCF 1, and correspondingly, the P-CSCF 1 receives the response message from the SMF 1; wherein the response message is a response message of the request message.

[0328] The SMF 1 sends the identification information of the spaceborne UPF 1 and the network element level tunnel information of the spaceborne UPF 1 to the P-CSCF 1 through a response message of the request message. That is, the SMF 1 sends, in response to the request message, a response message including the identification information of the spaceborne UPF 1 and the network element level tunnel information of the spaceborne UPF 1 to the P-CSCF 1.

[0329] 503. The P-CSCF 1 sends a call request to the P-CSCF 2, and correspondingly, the P-CSCF 2 receives the call request from the P-CSCF 1.

[0330] After the SMF 1 determines the session UPF of the first terminal device, the P-CSCF corresponding to the calling UE, i.e., the P-CSCF 1, sends a call request to the P-CSCF corresponding to the called UE, i.e., the P-CSCF 2. The call request includes the IP address of the first terminal device, the identification information of the spaceborne UPF 1, and the tunnel information of the spaceborne UPF 1.

[0331] 504. The P-CSCF 2 sends a request message to the SMF 2, and correspondingly, the SMF 2 receives the request message from the P-CSCF 2.

[0332] When the P-CSCF 2 determines that the second terminal device also accesses through the low-orbit regenerative satellite, the P-CSCF 2 sends a request message to the SMF 2 serving the second terminal device, and the request message is used to instruct the SMF 2 to establish an inter-satellite path for a session between the first terminal device and the second terminal device, so that the first terminal device and the second terminal device can forward data packets through the satellite without passing through the ground network device. The request message includes the IP address of the first terminal device, the identification information of the spaceborne UPF 1, and the tunnel information of the spaceborne UPF 1.

[0333] It should be noted that, similar to the P-CSCF 1, the P-CSCF 2 can also send a request message to the SMF 2 through the PCF 2 serving the UE 2, and the specific process can be referred to the description of step 501. The request message sent by the P-CSCF 2 to the SMF 2 is different from the request message sent by the P-CSCF 1 to the SMF 1 in step 501. The request message sent by the P-CSCF 1 to the SMF 1 is used to request the SMF 1 to determine the spaceborne UPF 1 accessed by the first terminal device, while the request message sent by the P-CSCF 2 to the SMF 2 is used to request the SMF 2 to establish an inter-satellite path according to the identification information of the spaceborne UPF 1.

[0334] 505. The SMF 2 acquires the path state information.

[0335] The SMF 2 obtains path state information according to the identification information of the satellite borne UPF 1. The path state information is used to indicate the state of the satellite borne 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 FIG. 3, the first network element is the satellite borne UPF 1, the second NTN device is the second satellite shown in FIG. 3, and the second network element is the satellite borne UPF 2. Therefore, the path state information is used to indicate the path state between the satellite borne UPF 1 and the satellite borne UPF 2.

[0336] Specifically, the path state information is used to indicate whether the inter-satellite link between the satellite borne UPF 1 and the satellite borne UPF 2 is reachable, the link delay of the inter-satellite link, the link packet loss rate, and the like. For example, the path state information can be a path state value, that is, the state of the inter-satellite link between the satellite borne UPF 1 and the satellite borne UPF 2 can be represented by a specific numerical value. For example, 1 bit is used to represent whether the inter-satellite link is reachable. When the path state value is 0, it indicates that the inter-satellite link is not reachable. When the path state value is 1, it indicates that the inter-satellite link is reachable. For another example, the path state value can be the link delay or the link packet loss rate of the inter-satellite link, which is not limited here. The path state information can also be a set of path state values, or the path state value can indicate that the path state value is greater than or less than a preset threshold, which is not limited here. The path state information can also be a path available indication or a path unavailable indication. The path available indication indicates that the inter-satellite link between the satellite borne UPF 1 and the satellite borne UPF 2 is available. The path unavailable indication indicates that the inter-satellite link between the satellite borne UPF 1 and the satellite borne UPF 2 is not available. It should be noted that the availability of the inter-satellite link first refers to the reachability of the inter-satellite link. Secondly, the reachability of the inter-satellite link also includes that the delay of the inter-satellite link and / or the packet loss rate of the inter-satellite link is less than a threshold, which is not limited here.

[0337] In a possible implementation, the SMF 2 can indicate, through the path state subscription request, the satellite borne UPF 2 to send a path state notification message to the SMF 2 when entering the service area of the SMF 2. For details, refer to the description of steps 500c and 500d.

[0338] The SMF 2 determines the path state between the satellite borne UPF 2 and the satellite borne UPF 1 from the path states between the satellite borne UPF 2 and the plurality of adjacent satellite borne UPFs according to the identification information of the satellite borne UPF 1, thereby obtaining the path state information. When the plurality of adjacent satellite borne UPFs include the satellite borne UPF 1, the SMF 2 obtains the path state between the satellite borne UPF 2 and the satellite borne UPF 1 from the path states between the satellite borne UPF 2 and the plurality of satellite borne UPFs. When the plurality of adjacent satellite borne UPFs do not include the satellite borne UPF 1, the SMF 2 determines that the path state between the satellite borne UPF 2 and the satellite borne UPF 1 is unavailable.

[0339] In another possible implementation, the SMF 2 sends a query request message to the spaceborne UPF 2, the query request message comprising the identification information of the spaceborne UPF 1, the query request message being used to instruct the spaceborne UPF 2 to query the path state between the spaceborne UPF 2 and the spaceborne UPF 1 based on the identification information of the spaceborne UPF 1. After receiving the query request message, the spaceborne UPF 2 acquires the identification information of the spaceborne UPF 1. If the spaceborne UPF 2 does not configure the spaceborne UPF 1 as a neighboring spaceborne UPF, it is considered that there is no inter-satellite path between them, and at this time, the path between the spaceborne UPF 2 and the spaceborne UPF 1 is unavailable. If the spaceborne UPF 2 configures the spaceborne UPF 1 as a neighboring spaceborne UPF, the spaceborne UPF 2 obtains the path state information according to the monitoring result. The spaceborne UPF 2 sends a first response message to the SMF 2 in response to the query request message. If the inter-satellite path between the spaceborne UPF 1 and the spaceborne UPF 2 is available, the first response message comprises the path state information; if the inter-satellite path between the spaceborne UPF 1 and the spaceborne UPF 2 is unavailable, the first response message comprises an unavailable path indication.

[0340] It should be noted that the SMF 2 can also acquire the path state information by performing step 506. Specifically, the SMF 2 sends indication information to the spaceborne UPF 2 at the same time as sending the first splitting rule, the indication information being used to instruct the spaceborne UPF 2 to split according to the first splitting rule and return an available path indication in the case that the inter-satellite link between the spaceborne UPF 2 and the spaceborne UPF 1 is available. If the inter-satellite link is unavailable, an unavailable path indication is returned. In this case, the spaceborne UPF 2 can configure threshold information for judging whether the path is available or receive the threshold information from the SMF 2, such as a time delay threshold and a packet loss rate threshold, and judge that the path is available when the time delay of the inter-satellite path is less than the time delay threshold and the packet loss rate of the inter-satellite path is less than the packet loss rate threshold. In this case, the spaceborne UPF 2 first judges whether the inter-satellite path between the spaceborne UPF 2 and the spaceborne UPF 1 is available, installs the first splitting rule and sends a success indication in the response message if it is available, and does not install the first splitting rule and sends a failure indication in the response message if it is unavailable.

[0341] In the embodiments of the present application, the path state information is acquired from the spaceborne UPF 2, so that the SMF 2 does not need to query an external system, thereby avoiding the problem that the path state of the inter-satellite link cannot be queried due to the non-standardization of external interfaces.

[0342] 506. The SMF 2 sends a first splitting rule to the spaceborne UPF 2, and correspondingly, the spaceborne UPF 2 receives the first splitting rule from the SMF 2.

[0343] In a possible implementation, when the SMF 2 determines that the path state between the satellite UPF 1 and the satellite UPF 2 is in the available state, the SMF 2 sends a first split rule to the satellite UPF 2. The first split rule is used to instruct the satellite UPF 2 to send a first data packet to the satellite UPF 1 using the tunnel information of the satellite UPF 1, where 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 the satellite UPF 2 from the second terminal device. Wherein, sending the first data packet to the satellite UPF 1 using the tunnel information of the satellite UPF 1 means that the first data packet is encapsulated in the tunnel between the satellite UPF 1 and the satellite UPF 2 using the tunnel information of the satellite UPF 1, for example, assuming that IP in IP tunnel is used between the satellite UPF 1 and the satellite UPF 2, the tunnel information of the satellite UPF 1 includes the IP address of the satellite UPF 1, and optionally can also include tunnel type information, that is, the tunnel type is IP in IP, in this case, sending the first data packet using the tunnel information of the satellite UPF 2 means that a tunnel header is added outside the first data packet, the tunnel header is an IP header, and the destination address of the IP header is the IP address of the satellite UPF 1, and the source address is the IP address of the satellite UPF 2. The specific sending mode is related to the tunnel used between the satellite UPF 1 and the satellite UPF 2.

[0344] Specifically, the SMF 2 instructs the satellite UPF 2 to send the IMS media stream data packet sent by the second terminal device to the first terminal device to the satellite UPF 1, that is, the first split rule further includes protocol type information, and the protocol type indicates the IMS media stream. The satellite UPF 2 establishes a network element level tunnel with the satellite UPF 1 according to the tunnel information of the satellite UPF 1. The SMF 2 instructs the satellite UPF 2 to send the IMS media stream data packet sent to the first terminal device to the satellite UPF 1 through the network element level tunnel, and the SMF 2 needs to send the IP address of the first terminal device and the tunnel address of the satellite UPF 1 to the satellite UPF 2, so that the satellite UPF 2 can determine the media stream data packet that needs to be sent to the first terminal device according to the IP address of the first terminal device and the protocol type, that is, the first split rule includes the IP address of the first terminal device and the tunnel information of the satellite UPF 1. At the same time, the satellite UPF 2 sends the data packet received from the first terminal device to the second terminal device. In addition, the first split rule further includes the IP address of the second terminal device, which is used to determine that the data packet comes from the second terminal device.

[0345] The first split rule can also be used to instruct the satellite UPF 2 to allocate the tunnel information of the satellite UPF 2, and send the tunnel information of the satellite UPF 2 to the SMF 2 in a response message.

[0346] In another possible implementation, the SMF 2 does not determine whether the path state between the satellite UPF 1 and the satellite UPF 2 is in the available state, and the SMF 2 sends the indication information to the satellite UPF 2 at the same time of sending the first splitting rule to the satellite UPF 2. For details, refer to the description in step 505, which will not be repeated here.

[0347] In a possible embodiment, the SMF 2 can further send a second splitting rule to the satellite UPF 2, where the second splitting rule is used to instruct the second network element to send a first data packet to a session anchor point, the first data packet has a destination address of an IP address of the first terminal device, the first data packet is obtained by the second network element from a second terminal device, the session anchor point provides a service for the second terminal device, the session anchor point is a user plane anchor point of the second terminal device, in 5G, the session anchor point is a PSA, the second network element provides a service for the second terminal device, and the session anchor point is deployed in a first ground network, and the first ground network is a ground core network.

[0348] Specifically, the second splitting rule instructs the satellite UPF 2 to send the first data packet to the PSA 2, which is a session anchor point of the second terminal device deployed in the first ground network, and the first ground network is a ground core network. Based on the second splitting rule, the satellite UPF 2 sends the IMS media stream data packet for the first terminal device to the PSA 1 through the PSA 2, and then the PSA 1 forwards the first data packet to the satellite UPF 1. At the same time, the satellite UPF 2 sends the data packet received from the PSA 2 to the second terminal device.

[0349] In an embodiment, the SMF 2 sends the first indication information at the same time of sending the first splitting rule and the second splitting rule, where the first indication information is used to instruct the satellite UPF 2 to determine whether to use the first splitting rule to split the IMS media stream data packet or use the second splitting rule to split the IMS media stream data packet based on the path state.

[0350] In the embodiments of the present application, by sending the first splitting rule, the second splitting rule and the first indication information, the satellite UPF 2 can dynamically select the inter-satellite path or the ground path according to the path state, so as to select the optimal path, and thus the user can have a better call experience.

[0351] 507、The SMF 2 sends a response message or a notification message to the P-CSCF 2, and correspondingly, the P-CSCF 2 receives the response message or the notification message from the SMF 2.

[0352] The response message sent by the SMF 2 to the P-CSCF 2 is a response message corresponding to the request message sent by the P-CSCF 2 to the SMF 2 in step 504. The response message is used to indicate whether the inter-satellite path is successfully established. In the above-mentioned one embodiment, the SMF 2 judges based on the path status information, if the path status information indicates that the path status between the spaceborne UPF 1 and the spaceborne UPF 2 is in the available state, the SMF 2 sends the first splitting rule to establish the inter-satellite path, and the response message includes the tunnel information of the spaceborne UPF 2, and the response message can also indicate that the inter-satellite path is successfully established; if the path status information indicates that the path status between the spaceborne UPF 1 and the spaceborne UPF 2 is in the unavailable state, the response message includes an indication that the inter-satellite path is unavailable. In another embodiment, the SMF 2 sends the indication information while sending the first splitting rule, indicating that the spaceborne UPF 2 splits according to the first splitting rule when the inter-satellite path between the spaceborne UPF 2 and the spaceborne UPF 1 is available, the SMF 2 receives the response message of the spaceborne UPF 2, if the response message indicates success, the SMF 2 includes the tunnel information of the spaceborne UPF 2 in the response message sent to the P-CSCF 2, or if the response message indicates failure, the SMF 2 includes an indication that the inter-satellite path is unavailable in the response message sent to the P-CSCF 2.

[0353] If the SMF 2 indicates that the inter-satellite path is successfully established, the P-CSCF 2 indicates that the second terminal device directly sends the media stream to the first terminal device, that is, the P-CSCF 2 carries the IP address of the first terminal device in the message sent to the second terminal device.

[0354] 508. The P-CSCF 2 sends a call response to the P-CSCF 1, and correspondingly, the P-CSCF 1 receives the call response from the P-CSCF 2.

[0355] The call response is a response message corresponding to the call request in step 503. In the case of supporting the inter-satellite link in this session, that is, the SMF 2 indicates that the inter-satellite path is successfully established, the call response includes the identification information of the spaceborne UPF 2 and the tunnel information of the spaceborne UPF 2, and the call response also includes the IP address of the second terminal. The call response also includes a path indication, that is, the path used by the media stream between the first terminal and the second terminal. If the inter-satellite link is supported in this session, the path indication is used to indicate that the media stream between the first terminal and the second terminal adopts the inter-satellite path, that is, is forwarded through the inter-satellite link between the spaceborne UPF 1 and the spaceborne UPF 2.

[0356] 509. The P-CSCF 1 sends a request message to the SMF 1, and correspondingly, the SMF 1 receives the request message from the P-CSCF 1.

[0357] The request message has the same function as the request message sent by the P-CSCF 2 to the SMF 2 in step 504, that is, the P-CSCF 1 sends the request message to the SMF 1 to request the SMF 1 to establish an inter-satellite path for the session between the first terminal device and the second terminal device, so that the first terminal device and the second terminal device can forward data packets through the satellite without passing through the ground network device. Wherein, the request message includes the identification information of the on-board UPF 2, the tunnel information of the on-board UPF 2 and the identification information of the second terminal device. The request message can also include the identification information of the first terminal device and the protocol number of the media stream data packet between the first terminal device and the second terminal device. For details, please refer to step 504.

[0358] 510、The SMF 1 sends a fifth split rule to the on-board UPF 1, and correspondingly, the on-board UPF 1 receives the fifth split rule from the SMF 1.

[0359] Step 510 is similar to step 506 in the embodiment, but the fifth split rule is in the opposite direction of the first split rule, that is, the fifth split rule instructs the on-board UPF 1 to send the fifth data packet to the on-board UPF 2 using the tunnel information of the on-board UPF 2, wherein the fifth data packet is the media stream data packet sent by the first terminal device to the second terminal device. For details, please refer to step 506, in which the on-board UPF 2 in the first split rule is replaced by the on-board UPF 1, the on-board UPF 1 is replaced by the on-board UPF 2, the first terminal is replaced by the second terminal, the second terminal is replaced by the first terminal, the SMF 2 is replaced by the SMF 1, the first split rule is replaced by the fifth split rule, and the first data packet is replaced by the fifth data packet. Here, no longer be described.

[0360] In the embodiment, the SMF queries the inter-satellite path through the on-board UPF, and then decides whether to enable UE-SAT-UE communication based on the reachability of the inter-satellite path, so that the SMF does not need to query an external system to obtain the inter-satellite path state, avoiding the problem that the inter-satellite path reachability cannot be queried and obtained.

[0361] Optionally, the embodiment shown in FIG. 5 further includes step 500a. Step 500a can be performed before step 501.

[0362] 500a、The SMF 1 sends a path state subscription request to the on-board UPF 1, and correspondingly, the on-board UPF 1 receives the path state subscription request from the SMF 1.

[0363] When the satellite-borne UPF 1 enters the service area of the SMF 1, the SMF 1 sends a path state subscription request to the satellite-borne UPF 1, the path state subscription request being used to request to obtain the state of the inter-satellite path between the satellite-borne UPF 1 and all configured neighboring satellite-borne UPFs. The path state subscription request can also request to obtain a path state change report when the path state between the satellite-borne UPF 1 and a neighboring satellite-borne UPF changes. For example, when the state of the inter-satellite path between the satellite-borne UPF 1 and any configured neighboring satellite-borne UPF changes from reachable to unreachable, or from unreachable to reachable, a path state change report is sent to the SMF 1. For another example, the SMF 1 can configure a preset threshold in the path state subscription request, and when the link delay or the link packet loss rate of the inter-satellite link between the satellite-borne UPF and any configured neighboring satellite-borne 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 state change report is sent to the SMF 1, together with the latest path state information.

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

[0365] 500b. The satellite-borne UPF 1 sends a path state notification message to the SMF 1, and correspondingly, the SMF 1 receives the path state notification message from the satellite-borne UPF 1.

[0366] The satellite-borne UPF 1 sends a path state notification message to the SMF 1 in response to the path state subscription request, the path state notification message carrying the state of the inter-satellite path between the satellite-borne UPF 1 and all configured neighboring satellite-borne UPFs.

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

[0368] 500c. The SMF 2 sends a path state subscription request to the satellite-borne UPF 2, and correspondingly, the satellite-borne UPF 2 receives the path state subscription request from the SMF 2.

[0369] Step 500c is similar to step 500a in the present embodiment, and details are not repeated here.

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

[0371] 500d. The satellite-borne UPF 2 sends a path state notification message to the SMF 2, and correspondingly, the SMF 2 receives the path state notification message from the satellite-borne UPF 2.

[0372] Step 500d is similar to step 500b in the present embodiment, and details are not repeated here.

[0373] Optionally, the embodiment shown in FIG. 5 further includes step 509a. Step 509a can be performed after step 509.

[0374] 509a, SMF1 acquires path state information;

[0375] Step 509a is similar to step 505 in the embodiment, and details are not repeated here.

[0376] In actual application, since the satellite is in constant motion, the path state between the satellite-borne UPF1 and the satellite-borne UPF2 can change. For example, the path state between the satellite-borne UPF1 and the satellite-borne UPF2 changes from the available state to the unavailable state. For another example, the path state between the satellite-borne UPF1 and the satellite-borne UPF2 changes from the unavailable state to the available state.

[0377] Taking the path state between the satellite-borne UPF1 and the satellite-borne UPF2 changing from the available state to the unavailable state as an example. Please refer to FIG. 6, which is another schematic diagram of the communication method provided in the embodiment of the application. The method shown in FIG. 6 is interactively performed by the satellite-borne UPF1, the satellite-borne UPF2, the SMF1, the SMF2, the P-CSCF1 and the P-CSCF2. Among them, the method shown in FIG. 6 can be applied to the application scenario shown in FIG. 3, the satellite-borne UPF1 corresponds to the UPF on the first satellite, the satellite-borne UPF2 corresponds to the UPF on the second satellite, the SMF1, the SMF2, the P-CSCF1 and the P-CSCF2 are all network devices deployed on the ground. The satellite-borne UPF1 is the first network element or the third network element, the satellite-borne UPF2 is the second network element or the 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, and the P-CSCF2 is the second proxy call session control function. In the embodiment of the application, the UE1 is the first terminal device, the UE2 is the second terminal device, the SMF1 is responsible for managing the satellite-borne UPF1, and the SMF2 is responsible for managing the satellite-borne UPF2. The method includes steps 601 to 606.

[0378] 601, the satellite-borne UPF1 sends a path state change report to the SMF1, and correspondingly, the SMF1 receives the path state change report from the satellite-borne UPF1; wherein the path state change report can be first information for indicating that the path state between the first network element and the second network element changes.

[0379] Based on step 500a in the embodiment shown in FIG. 5, the SMF 1 indicates, by the path status subscription request, that the spaceborne UPF 1 sends a path status change report in case that the path status between the spaceborne UPF 1 and the spaceborne UPF 2 changes. In this embodiment, the SMF 1 determines, according to the path status change report, that the path status between the spaceborne UPF 1 and the spaceborne UPF 2 changes from the available state to the unavailable state.

[0380] 602. The SMF 1 sends a notification message to the P-CSCF 1, and correspondingly, the P-CSCF 1 receives the notification message from the SMF 1.

[0381] The SMF 1 sends a notification message to the SMF 1 in case that the path status between the spaceborne UPF 1 and the spaceborne UPF 2 changes.

[0382] Optionally, the notification message includes path status change information. The path status change information is used by the SMF 1 to indicate, to the P-CSCF 1, that the path between the spaceborne UPF 1 and the spaceborne UPF 2 is available or unavailable based on the path status change report, i.e., the path status change information is used to indicate whether the inter-satellite path is available.

[0383] When the path status change information is used to indicate that the path between the spaceborne UPF 1 and the spaceborne UPF 2 is unavailable, the notification message includes an unavailable path indication. Similarly, when the path status change information is used to indicate that the path between the spaceborne UPF 1 and the spaceborne UPF 2 is available, the notification message includes an available path indication.

[0384] 603. The SMF 1 sends a second splitting rule to the spaceborne UPF 1, and correspondingly, the spaceborne UPF 1 receives the second splitting rule from the SMF 1.

[0385] When the inter-satellite path between the spaceborne UPF 1 and the spaceborne UPF 2 is unavailable, the SMF 1 instructs the spaceborne UPF 1 to change the transmission path between the first terminal device and the second terminal device from the inter-satellite path to the ground path. The SMF 1 sends a second splitting rule to the spaceborne UPF 1, which can be referred to the description of step 506 in the embodiment shown in FIG. 5, and details are not described here.

[0386] Optionally, the SMF 1 instructs the spaceborne UPF 1 to delete the first splitting rule when sending the second splitting rule.

[0387] The spaceborne UPF 1 receives the second splitting rule and cancels the first splitting rule according to the instruction, i.e., the spaceborne UPF 1 no longer sends the data packet with the IP address of the second terminal device as the destination to the spaceborne UPF 2 through the tunnel information of the spaceborne UPF 2, but sends the data packet to the PSA 1.

[0388] Optionally, the SMF 1 can delete the spaceborne UPF 1 from the session path, so that the first terminal device sends an uplink data packet to the access network device on the first satellite, and the access network device on the first satellite directly sends the uplink data packet sent by the first terminal device to the PSA 1.

[0389] 604、The P-CSCF 1 sends a switching path notification to the P-CSCF 2, and correspondingly, the P-CSCF 2 receives the switching path notification from the P-CSCF 1.

[0390] The P-CSCF 1 sends a switching path notification to the P-CSCF 2 to instruct the P-CSCF 2 to convert the inter-satellite path to the ground path. Specifically, the switching path notification can be the fourth information or be carried in the fourth information. The switching path notification is used to instruct to switch the first path to the second path, wherein the first path is a path of the first terminal device to the second terminal device through the third network element and the fourth network element, i.e., a path of UE 1 to UE 2 through the spaceborne UPF 1 and the spaceborne UPF 2; and the second path is a path of the first terminal device to the second terminal device through the session anchor, i.e., a path of UE 1 to UE 2 through the PSA 1 and the PSA 2.

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

[0392] It should be noted that the timing between steps 603 and 604 is not limited in the embodiments of the present application. Step 603 can be performed before step 604, or can be performed after step 604, which is not limited herein.

[0393] 605、The P-CSCF 2 sends a switching path notification to the SMF 2, and correspondingly, the SMF 2 receives the switching path notification from the P-CSCF 2.

[0394] The P-CSCF 2 sends a switching path notification to the SMF 2 to instruct the SMF 2 to switch the inter-satellite path to the ground path. Specifically, the switching path notification can be or carry the first information or the fourth information used to instruct to switch the transmission path between the first network element and the second network element. The switching path notification is used to instruct to switch the first path to the second path, where the first path is a path from the first terminal device to the second terminal device through the third network element and the fourth network element, i.e., a path from the first terminal device to the second terminal device through the spaceborne UPF 1 and the spaceborne UPF 2, and the second path is a path from the first terminal device to the second terminal device through the session anchor, i.e., a path from the first terminal device to the second terminal device through the PSA 1 and the PSA 2.

[0395] 606. The SMF 2 sends a second splitting rule to the spaceborne UPF 2, and correspondingly, the spaceborne UPF 2 receives the second splitting rule from the SMF 2.

[0396] The step 606 is similar to the step 603 in the embodiment, and details are not described herein.

[0397] In the embodiment, the ground path can be switched when the inter-satellite path changes from available to unavailable, thereby ensuring the continuity of the call service and preventing the call service from being interrupted.

[0398] It should be understood that the embodiment shown in FIG. 6 takes the path state between the spaceborne UPF 1 and the spaceborne UPF 2 changing from the available state to the unavailable state as an example. In actual applications, the path state between the spaceborne UPF 1 and the spaceborne UPF 2 can also change from the unavailable state to the available state. At this time, the step 603 in the embodiment shown in FIG. 6 is changed to the SMF 1 sending a first splitting rule to the spaceborne UPF 1, so that the spaceborne UPF 1 transmits data packets using the inter-satellite path according to the first splitting rule. Similarly, the step 606 is changed to the SMF 2 sending the first splitting rule to the spaceborne UPF 2. At the same time, the path state change report in the step 601 is used to instruct the path state between the spaceborne UPF 1 and the spaceborne UPF 2 to change from the unavailable state to the available state.

[0399] When the inter-satellite path is switched to the ground path, the ground path can also be transmitted through the ground access gateway deployed in the second ground network. Please refer to FIG. 7, which is another schematic diagram of a communication method provided in the embodiments of the present application. The method shown in FIG. 7 is interactively performed by UE1, UE2, spaceborne UPF1, spaceborne UPF2, SMF1, SMF2, ground AGW1, ground AGW2, P-CSCF1 and P-CSCF2. Among them, the method shown in FIG. 7 can be applied to the application scenario shown in FIG. 3, the spaceborne UPF1 corresponds to the UPF on the first satellite, the spaceborne UPF2 corresponds to the UPF on the second satellite, the SMF1, SMF2, ground AGW1, ground AGW2, P-CSCF1 and P-CSCF2 are all network devices deployed on the ground. The spaceborne UPF1 is the first network element or the third network element, the spaceborne UPF2 is the second network element or the 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, the ground access gateway is the ground AGW1 or the ground AGW2, and the second ground network is the IMS network. In the embodiments of the present application, the UE1 is the first terminal device or the third terminal device, the UE2 is the second terminal device or the fourth terminal device, the SMF1 is responsible for managing the spaceborne UPF1, and the SMF2 is responsible for managing the spaceborne UPF2. The method includes steps 701 to 712.

[0400] 701. The spaceborne UPF1 sends a path state change report to the SMF1, and correspondingly, the SMF1 receives the path state change report from the spaceborne UPF1; wherein the path state change report can be first information for indicating that the path state between the first network element and the second network element has changed.

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

[0402] The steps 701 to 702 in the embodiments are similar to the steps 601 to 602 in the foregoing embodiments shown in FIG. 6, and will not be described here in detail.

[0403] 703. The P-CSCF1 selects and configures the ground AGW1.

[0404] The P-CSCF1 selects the ground AGW1 and configures the ground AGW1, so as to establish a media stream path for the call between the UE1 and the UE2. Among them, the ground AGW1 provides the IMS call service for the UE1.

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

[0406] The P-CSCF1 sends the switching path notification to the P-CSCF2 to instruct the P-CSCF2 to convert the inter-satellite path to the ground path. Specifically, the switching path notification can be the fourth information or be carried in the fourth information. The switching path notification is used to instruct to switch the first path to the second path, where the first path is a path of the first terminal device to the second terminal device through the third network element and the fourth network element, i.e., a path of the UE1 to the UE2 through the spaceborne UPF1 and the spaceborne UPF2; and the second path is a path of the first terminal device to the second terminal device through the ground access gateway, i.e., a path of the first terminal device to the second terminal device through the ground AGW1 and the ground AGW2.

[0407] 705、P-CSCF1 sends second indication information to UE1, and correspondingly, UE1 receives the second indication information from P-CSCF1.

[0408] The P-CSCF1 sends the second indication information to the UE1, and when the UE1 performs according to the second indication information, the communication path of the UE1 to the UE2 will be switched from the first path to the second path, where the first path is a path of the first terminal device to the second terminal device through the third network element and the fourth network element, i.e., a path of the UE1 to the UE2 through the spaceborne UPF1 and the spaceborne UPF2; and the second path is a path of the first terminal device to the second terminal device through the ground access gateway, i.e., a path of the UE1 to the UE2 through the ground AGW1 and the ground AGW2.

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

[0410] It should be noted that the timing between the step 704 and the step 705 is not limited in the embodiment. The step 704 can be performed before the step 705, or can be performed after the step 705, which is not limited herein.

[0411] 706、P-CSCF2 selects and configures the ground AGW2.

[0412] The step 706 is similar to the step 703 in the embodiment, which is not described herein again.

[0413] 707、P-CSCF2 sends second indication information to UE2, and correspondingly, UE2 receives the second indication information from P-CSCF2.

[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 split rule is used to instruct the spaceborne UPF 2 to receive a fourth data packet from the PSA 2, wherein the fourth data packet is sent by the ground AGW 2 to the UE 2 through the PSA 2 and the spaceborne UPF 2, i.e., the destination address of the fourth data packet is the IP address of the UE 2.

[0425] Alternatively, in another optional implementation, the SMF 2 can also delete the spaceborne UPF 2 from the call path, i.e., instruct the PSA 2 to directly send the data packet received from the ground AGW 2 to the UE 2 to the spaceborne base station (i.e., the base station deployed on the same satellite as the spaceborne UPF 2), and instruct the spaceborne base station to send the data packet received from the UE 2 to the ground AGW 2 to the PSA 2.

[0426] 711. The P-CSCF 1 sends the second service flow information to the SMF 1, and correspondingly, the SMF 1 receives the second service flow information from the P-CSCF 1.

[0427] The second service flow information is the service flow information between the first terminal device and the ground access gateway, i.e., the service flow information between the UE 1 and the ground AGW 1.

[0428] Step 711 is executed after step 704, i.e., the P-CSCF 1 triggers step 710 in response to receiving the response message of the handover path notification message of step 704 sent by the P-CSCF 2.

[0429] 712. The SMF 1 sends the sixth split rule to the spaceborne UPF 1, and correspondingly, the spaceborne UPF 1 receives the sixth split rule from the SMF 1.

[0430] Step 712 is similar to step 710 in this embodiment, and details are not repeated here. The sixth split rule in step 712 is similar to the third split rule, but the sixth split rule and the third split rule are in opposite directions, and details are not repeated here.

[0431] It should be understood that the embodiment shown in FIG. 7 takes the path state between the spaceborne UPF1 and the spaceborne UPF2 changing from the available state to the unavailable state as an example. In actual applications, the path state between the spaceborne UPF1 and the spaceborne UPF2 can also change from the unavailable state to the available state, in which case step 712 in the embodiment shown in FIG. 7 is changed to the SMF1 sending the first split rule to the spaceborne UPF1, so that the spaceborne UPF1 transmits the data packet according to the first split rule using the inter-satellite path. Similarly, step 710 is changed to the SMF2 sending the fifth split rule to the spaceborne UPF2. Meanwhile, the path state change report in step 701 is used to indicate that the path state between the spaceborne UPF1 and the spaceborne UPF2 changes from the unavailable state to the available state. If the spaceborne UPF is deleted in step 712 or step 710, the spaceborne UPF should also be reinserted, that is, the base station is notified to send the uplink data packet to the spaceborne UPF, and the ground PSA is notified to send the downlink data packet to the spaceborne UPF.

[0432] It should be understood that the embodiments shown in FIG. 6 and FIG. 7 take the spaceborne UPF1 sending the path state report as an example for description. In actual applications, the spaceborne UPF2 can also send the path state report, or the spaceborne UPF1 and the spaceborne UPF2 both send the path state report. When the spaceborne UPF1 and the spaceborne UPF2 both send the path state report, if the handover process has been triggered, the SMF or the P-CSCF can not process the repeated triggering.

[0433] In the embodiments shown in FIG. 6 and FIG. 7, the handover of the path needs the control plane to participate. Please refer to FIG. 8, which is another schematic diagram of a communication method provided by the embodiments of the present application. In the method, two media stream paths can be established between UE1 and UE2 at the same time when a session is established, the path is monitored by the UE, and the path adopted for sending the media stream data packet is determined based on the monitoring result.

[0434] The method shown in FIG. 8 is interactively performed by UE1, UE2, spaceborne UPF1, spaceborne UPF2, SMF1, SMF2, ground AGW1, ground AGW2, P-CSCF1 and P-CSCF2. Among them, the method shown in FIG. 8 can be applied to the application scenario shown in FIG. 3, the spaceborne UPF1 corresponds to the UPF on the first satellite, the spaceborne UPF2 corresponds to the UPF on the second satellite, the SMF1, the SMF2, the ground AGW1, the ground AGW2, the P-CSCF1 and the P-CSCF2 are all network devices deployed on the ground. The spaceborne UPF1 is the first network element or the third network element, the spaceborne UPF2 is the second network element or the 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, the ground access gateway is the ground AGW1 or the ground AGW2, and the second ground network is the IMS network. In the embodiment of the application, the UE1 is the first terminal device or the third terminal device, the UE2 is the second terminal device or the fourth terminal device, the SMF1 is responsible for managing the spaceborne UPF1, and the SMF2 is responsible for managing the spaceborne UPF2. The method comprises steps 801 to 813.

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

[0436] The implementation of step 801 can refer to steps 501 to 502 in the embodiment shown in the foregoing FIG. 5, and details are not repeated here.

[0437] 802. The P-CSCF1 configures the ground AGW1.

[0438] Step 802 in the embodiment is similar to step 703 in the embodiment shown in the foregoing FIG. 7, and details are not limited here.

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

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

[0441] 804. The P-CSCF2 configures the ground AGW2.

[0442] Step 804 in the embodiment is similar to step 706 in the embodiment shown in the foregoing FIG. 7, and details are not limited here.

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

[0444] SMF2 establishes the inter-satellite path and the ground path simultaneously in response to the request message. The establishment of the inter-satellite path can refer to steps 505 in the embodiment shown in FIG. 5 and step 708 in FIG. 7, and details are not described herein again.

[0445] 806、SMF2 sends the first steering rule and the third steering rule to the spaceborne UPF2, and correspondingly, the spaceborne UPF2 receives the first steering rule and the third steering rule from SMF2.

[0446] SMF2 sends the two sets of steering rules to the spaceborne UPF2, so that the spaceborne UPF2 can use the first steering rule or the third steering rule to transmit data according to the transmission path determined by UE2.

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

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

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

[0450] In a possible implementation, SMF2 can determine whether the inter-satellite path is available before sending the response message to P-CSCF2. The method for determining whether the inter-satellite path is available can refer to step 507 in the embodiment shown in FIG. 5. If the inter-satellite path is available, SMF2 can include an indication that the inter-satellite path is available in the response message or the notification message.

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

[0452] The P-CSCF 2 sends call signaling to the UE 2, the call signaling including an IP address of the third terminal device and an IP address of the ground access gateway, i.e., the call signaling including the IP address of the UE 1 and the IP address of the ground AGW 2. The IP address of the third terminal device is used to indicate the first path, and the IP address of the ground access gateway is used to indicate the second path. The first path is a path from the third terminal device to the fourth terminal device through the third network element and the fourth network element, i.e., a path from the UE 1 to the UE 2 through the spaceborne UPF 1 and the spaceborne UPF 2; and the second path is a path from the third terminal device to the fourth terminal device through the ground access gateway, i.e., a path from the UE 1 to the UE 2 through the ground AGW 1 and the ground AGW 2.

[0453] Optionally, the call signaling further includes third indication information, the third indication information being used to instruct the UE 2 to use the first path or the second path to transmit data according to path states of the first path and the second path.

[0454] As an example, if the path state of the first path is an available state, the UE 2 uses the first path to transmit data; if the path state of the first path is an unavailable state, the UE 2 uses the second path to transmit data.

[0455] Optionally, the call signaling further includes a path selection policy, the path selection policy being used for the UE 1 to select a path, the path selection policy including one or more of initial path indication, path priority, path with low latency, path with low packet loss rate, path latency threshold and path packet loss rate threshold. The initial path indication is used to indicate an initial path used by the UE 2, and the path priority is used to indicate a preferred path in the first path and the second path. The path priority can also be used to indicate the path with low latency or the path with low packet loss rate, which is not limited here. As an example, if the P-CSCF 2 receives an indication that the first path (i.e., the inter-satellite path) is available from the SMF 2, the P-CSCF 2 can indicate in the call signaling that the UE initially uses the first path. The path latency threshold and the path packet loss rate threshold included in the path selection policy are used to monitor the availability of the path, i.e., when the path latency and the path packet loss rate are less than the path latency threshold and the path packet loss rate threshold respectively, it indicates that the path is available. When the path is available, the path is selected according to the path priority. For example, assuming that the first path and the second path are both available, and the priority of the first path is higher, the first path is selected. For another example, assuming that the path selection policy indicates to select the path with low latency, and according to the path monitoring, the latency of the second path is lower, the second path is selected.

[0456] Optionally, the call signaling further includes fourth indication information, the fourth indication information being used to instruct the UE 2 to perform path monitoring on the first path and the second path, so as to obtain path states of the first path and the second path.

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

[0458] The call response is a response message corresponding to the call request in step 803. The response message carries information of the ground path and the inter-satellite path. The information of the inter-satellite path includes the identification information of the spaceborne UPF2, the IP address of UE2 and the tunnel information of the spaceborne UPF2. The information of the ground path includes the address of the ground AGW2. The message can also indicate that the ground path and the inter-satellite path are established simultaneously. The message can also include the path selection policy described in step 808.

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

[0460] 811、SMF1 sends the fifth and sixth split rules to the spaceborne UPF1, and correspondingly, the spaceborne UPF1 receives the fifth and sixth split rules from SMF1.

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

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

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

[0464] After the first path and the second path are established, the terminal device monitors the first path and / or the second path, and selects a path according to the path selection policy and the monitoring result. For example, if the selection policy prefers the first path, when the first path is available, the terminal device preferentially uses the first path to send data packets.

[0465] In the embodiments of the present application, two paths, the first path and the second path, are created when a call is established, and the terminal device determines the path for sending media stream data packets based on the monitoring result of the first path and / or the second path and the path selection policy, which reduces the transmission delay and packet loss, and can dynamically select the inter-satellite path or the ground path according to the path state, so as to select the optimal path, and thus the user can have a better call experience.

[0466] Optionally, the embodiment shown in FIG. 8 further includes step 800a. Step 800a can be performed before step 801.

[0467] 800a, the SMF1 sends a path status subscription request to the spaceborne UPF1, and correspondingly, the spaceborne UPF1 receives the path status subscription request from the SMF1.

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

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

[0470] Optionally, the embodiment shown in FIG. 8 further includes step 800c. Step 800c can be performed before step 801.

[0471] 800c, the SMF2 sends a path status subscription request to the spaceborne UPF2, and correspondingly, the spaceborne UPF2 receives the path status subscription request from the SMF2.

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

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

[0474] Steps 800a to 800d in this embodiment are similar to steps 500a to 500d in the aforementioned embodiment shown in FIG. 5, and will not be described here again.

[0475] Please refer to FIG. 9, which is another schematic diagram of the communication method provided in the embodiments of the present application. The method shown in FIG. 9 is interactively performed by UE1, UE2, spaceborne AGW1, spaceborne AGW2, SMF1, SMF2, ground AGW1, ground AGW2, P-CSCF1 and P-CSCF2. Among them, the method shown in FIG. 9 can be applied to the application scenario shown in FIG. 4, the spaceborne UPF1 corresponds to the AGW on the first satellite, the spaceborne UPF2 corresponds to the AGW on the second satellite, the SMF1, SMF2, ground AGW1, ground AGW2, P-CSCF1 and P-CSCF2 are all network devices deployed on the ground. The spaceborne AGW1 is the third network element, the spaceborne AGW2 is the 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, the ground access gateway is the ground AGW1 or the ground AGW2, and the second ground network is the IMS network. In the embodiments of the present application, the UE1 is the third terminal device, the UE2 is the fourth terminal device, the SMF1 is responsible for managing the spaceborne UPF1, and the SMF2 is responsible for managing the spaceborne UPF2. The method includes steps 901 to 910.

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

[0477] The P-CSCF1 receives a SIP Invite request from the third terminal device (i.e., UE1), and the SIP Invite request includes the identification information of the fourth terminal device (i.e., UE2). The 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, which is not limited here. Based on the SIP Invite request of the third terminal device, the P-CSCF1 determines the spaceborne AGW1, which is deployed in the same NTN device as the spaceborne access network device accessed by the UE1.

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

[0479] The call request includes the identification information of the spaceborne AGW1.

[0480] 903. The P-CSCF2 obtains the path state information.

[0481] If UE2 is also currently accessing through the regenerative satellite, P-CSCF2 selects the on-board AGW2. P-CSCF2 obtains path state information according to the identification information of on-board AGW1. The path state information is used to indicate the state of the on-board 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 FIG. 4, the third network element is on-board AGW1, the second NTN device is the second satellite shown in FIG. 4, and the fourth network element is AGW2. Therefore, the path state information is used to indicate the state of the inter-satellite link between on-board AGW1 and on-board AGW2.

[0482] Specifically, the path state information is used to indicate whether the inter-satellite link between on-board AGW1 and on-board AGW2 is reachable, the link delay of the inter-satellite link, the link packet loss rate, and the like. For example, the path state information can be a path state value, i.e., the state of the inter-satellite link between on-board AGW1 and on-board AGW2 can be represented by a specific numerical value. For example, 1 bit is used to represent whether the inter-satellite link is reachable. When the path state value is 0, it indicates that the inter-satellite link is not reachable. When the path state value is 1, it indicates that the inter-satellite link is reachable. For another example, the path state value can be the link delay or the link packet loss rate of the inter-satellite link, which is not limited here. The path state information can also be a set of path state values, or the path state value can indicate that the path state value is greater than or less than a preset threshold, which is not limited here. The path state information can also be a path available indication or a path unavailable indication. The path available indication indicates that the inter-satellite link between on-board AGW1 and on-board AGW2 is available, and the path unavailable indication indicates that the inter-satellite link between on-board AGW1 and on-board AGW2 is not available, which is not limited here.

[0483] In a possible implementation, P-CSCF2 can send a path state subscription request indication to on-board AGW2, and send a path state notification message to P-CSCF2 when entering the service area of P-CSCF2. For details, refer to the description of steps 900c and 900d.

[0484] P-CSCF 2 determines the path state between the satellite AGW 2 and the satellite AGW 1 from the path state information between the satellite AGW 2 and the plurality of adjacent satellite AGWs according to the identification information of the satellite AGW 1, thereby obtaining the path state information. When the plurality of adjacent satellite AGWs includes the satellite AGW 1, the P-CSCF 2 can obtain the path state between the satellite AGW 2 and the satellite AGW 1 from the path state information between the satellite AGW 2 and the plurality of adjacent satellite AGWs. When the plurality of adjacent satellite AGWs does not include the satellite AGW 1, the P-CSCF 2 can determine that there is no available inter-satellite path between the satellite AGW 1 and the satellite AGW 2, i.e., the state of the inter-satellite path is unavailable.

[0485] In another possible implementation, the P-CSCF 2 sends a query request message to the satellite AGW 2, the query request message including the identification information of the satellite AGW 1, the query request message being used to instruct the satellite AGW 2 to query the path state between the satellite AGW 2 and the satellite AGW 1 based on the identification information of the satellite AGW 1. After receiving the query request message, the satellite AGW 2 obtains the identification information of the satellite AGW 1. If the satellite AGW 2 does not configure the satellite AGW 1 as an adjacent satellite AGW, it is considered that there is no inter-satellite path between them. If the satellite AGW 2 configures the satellite AGW 1 as an adjacent satellite AGW, the satellite AGW 2 obtains the path state information according to the monitoring result. The satellite AGW 2 sends a first response message to the P-CSCF 2 in response to the query request message. If the inter-satellite path between the satellite AGW 1 and the satellite AGW 2 is available, the first response message includes the path state information. If the inter-satellite path between the satellite AGW 1 and the satellite AGW 2 is unavailable, the first response message includes an indication that the path is unavailable.

[0486] The P-CSCF 2 can first query the satellite AGW 2 about the availability of the inter-satellite path between the satellite AGW 2 and the satellite AGW 1, and configure the satellite AGW 2 when the inter-satellite path is available. The P-CSCF 2 can also directly configure the satellite AGW 2 and indicate that the path is an inter-satellite path. The satellite AGW 2 determines the availability of the inter-satellite path between the satellite AGW 2 and the satellite AGW 1 according to the indication, and continues the configuration if the inter-satellite path is available, or returns a failure and indicates that the inter-satellite path is unavailable.

[0487] 904、The P-CSCF 2 sends a call signaling to the UE 2, and the UE 2 receives the call signaling from the P-CSCF 2.

[0488] The P-CSCF 2 sends a call signaling to the UE 2, and the call signaling includes the IP address of the fourth network element, i.e., the call signaling includes the IP address of the satellite AGW 2.

[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 service flow information between the fourth terminal device and the fourth network element, i.e., service flow information between UE2 and the spaceborne AGW2. In response to the third service flow information, SMF2 performs step 906.

[0491] 906、SMF2 configures the spaceborne UPF2.

[0492] SMF2 receives the indication from P-CSCF2 and configures the spaceborne UPF2 according to the indication, so as to support sending data received from the spaceborne AGW2 and needing to be sent to UE2 to an access network device on the second satellite, so as to be sent to UE2. Meanwhile, data packets sent by UE2 to the spaceborne AGW2 are sent to the spaceborne AGW2.

[0493] Alternatively, in another optional implementation, SMF2 can also delete the spaceborne UPF2 from the call path, i.e., instructing PSA2 to directly send data packets received from the ground AGW2 and sent to UE2 to a spaceborne base station (i.e., a base station deployed on the same satellite as the spaceborne UPF2), and instructing the spaceborne base station to send 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 correspondingly, P-CSCF1 receives the call response from P-CSCF2.

[0495] The call response is a response message corresponding to the call request in step 902. In the case of supporting the inter-satellite link in this session, the call response includes identification information of the spaceborne AGW2 and an IP address of UE2. The call response is also used to instruct P-CSCF1 to establish an inter-satellite path.

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

[0497] 909、P-CSCF1 sends 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 service flow information between the third terminal device and the third network element, i.e., service flow information between UE1 and the spaceborne AGW1. In response to the fourth service flow information, SMF1 performs step 910.

[0499] 910、SMF1 configures the spaceborne UPF1.

[0500] Step 910 is similar to step 906 in the embodiment, and details are not repeated here.

[0501] Optionally, the embodiment shown in FIG. 9 further includes step 900a. Step 900a can be performed before step 901.

[0502] In the embodiment, the P-CSCF queries the inter-satellite path through the on-board AGW, and determines whether to enable the UE-SAT-UE communication based on the reachability of the inter-satellite path, so that the P-CSCF does not need to query an external system to obtain the inter-satellite path state, and the problem of being unable to query the inter-satellite path reachability due to the non-standardization of external interfaces is avoided.

[0503] 900a. The P-CSCF 1 sends a path state subscription request to the on-board AGW 1, and correspondingly, the on-board AGW 1 receives the path state subscription request from the P-CSCF 1.

[0504] When the on-board AGW 1 enters the service area of the P-CSCF 1, the P-CSCF 1 sends a path state subscription request to the on-board AGW 1, which is used to request to obtain the state of the inter-satellite path between the on-board AGW 1 and all configured neighboring on-board AGWs. The path state subscription request can also request to obtain a path state change report when the path state between the on-board AGW 1 and the neighboring on-board AGW changes. For example, when the state of the inter-satellite path between the on-board AGW 1 and any configured neighboring AGW changes from reachable to unreachable, or from unreachable to reachable, a path state change report is sent to the P-CSCF 1. For another example, the P-CSCF 1 can configure a preset threshold in the path state subscription request, and when the link delay or the link packet loss rate of the inter-satellite link between the on-board AGW and any configured neighboring on-board 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 state change report and the latest path state information are sent to the P-CSCF 1.

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

[0506] 900b. The on-board AGW 1 sends a path state notification message to the P-CSCF 1, and correspondingly, the P-CSCF 1 receives the path state notification message from the on-board AGW 1.

[0507] The on-board AGW 1 sends a path state notification message to the P-CSCF 1 in response to the path state subscription request, and carries the state of the inter-satellite path between the on-board AGW 1 and one or more AGWs in all configured neighboring on-board AGWs in the path state notification message.

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

[0509] 900c. P-CSCF 2 sends a path status subscription request to the spaceborne AGW 2, and correspondingly, the spaceborne AGW 2 receives the path status subscription request from the P-CSCF 2.

[0510] Step 900c is similar to step 900a in this embodiment, and details are not repeated here.

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

[0512] 900d. The spaceborne AGW 2 sends a path status notification message to the P-CSCF 2, and correspondingly, the P-CSCF 2 receives the path status notification message from the spaceborne AGW 2.

[0513] Step 900d is similar to step 900b in this embodiment, and details are not repeated here.

[0514] Optionally, the embodiment shown in FIG. 9 further includes step 907a. Step 907a can be performed after step 907.

[0515] 907a. The P-CSCF 1 acquires path status information.

[0516] Step 907a is similar to step 903 in this embodiment, and details are not repeated here.

[0517] In actual application, since the satellite is in constant motion, the path status between the spaceborne AGW 1 and the spaceborne AGW 2 can change. For example, the path status between the spaceborne AGW 1 and the spaceborne AGW 2 changes from the available state to the unavailable state. For another example, the path status between the spaceborne AGW 1 and the spaceborne AGW 2 changes from the unavailable state to the available state.

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

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

[0520] Based on step 900a in the embodiment shown in FIG. 9, the P-CSCF1 indicates, through the path state subscription request, that the satellite AGW1 sends a path state change report in the case that the path state between the satellite AGW1 and the satellite AGW2 changes. In the embodiments, the path state change report is used to indicate that the path state between the satellite AGW1 and the satellite AGW2 changes from an available state to an unavailable state.

[0521] 1002. The P-CSCF1 selects and configures the ground AGW1.

[0522] Step 1002 in the embodiments is similar to step 703 in the embodiment shown in FIG. 7, and will not be repeated here.

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

[0524] The P-CSCF 1 sends a switching path notification to the P-CSCF 2 to instruct the P-CSCF 2 to switch the inter-satellite path to the ground path. Specifically, the switching path notification can be the fourth information or carried in the fourth information. The switching path notification is used to instruct to switch the first path to the second path, where the first path is the path of the third terminal device to the fourth terminal device through the third network element and the fourth network element, i.e., the path of UE1 to UE2 through the satellite AGW1 and the satellite AGW2; and the second path is the path of the third terminal device to the fourth terminal device through the ground access gateway, i.e., the path of UE1 to UE2 through the ground AGW1 and the ground AGW2.

[0525] 1004. The P-CSCF 1 sends second indication information to UE1, and correspondingly, UE1 receives the second indication information from the P-CSCF 1.

[0526] The P-CSCF 1 sends second indication information to UE1 to instruct UE1 to switch the first path to the second path, where the first path is the path of the third terminal device to the fourth terminal device through the third network element and the fourth network element, i.e., the path of UE1 to UE2 through the satellite AGW1 and the satellite AGW2; and the second path is the path of the third terminal device to the fourth terminal device through the ground access gateway, i.e., the path of UE1 to UE2 through the ground AGW1 and the ground AGW2.

[0527] Specifically, the second indication information is used to instruct UE1 to change the destination address of the data packet sent to UE2 from the IP address of the satellite AGW1 to the IP address of the ground AGW1, so that the transmission path of UE1 is changed from the first path to the second path.

[0528] It should be noted that the timing between step 1003 and step 1004 is not limited in this embodiment. Step 1003 can be performed before step 1004, or can be performed after step 1004, which is not limited here. Step 1004 can be performed after receiving the response message of step 1003

[0529] 1005. The P-CSCF 2 selects and configures the ground AGW2.

[0530] Step 1005 in this embodiment is similar to step 706 in the foregoing embodiment shown in FIG. 7, which will not be repeated here.

[0531] 1006. The P-CSCF 2 sends second indication information to UE2, and correspondingly, UE2 receives the second indication information from the P-CSCF 2.

[0532] Step 1006 is similar to step 1004 in this embodiment, which will not be repeated here.

[0533] 1007、P-CSCF2 sends a switching path response to P-CSCF1, and correspondingly, P-CSCF1 receives the switching path response from P-CSCF2;

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

[0535] 1008、P-CSCF2 sends 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, i.e., the service flow information between UE2 and the ground AGW2. In response to the first service flow information, SMF2 performs step 1009.

[0537] 1009、SMF2 configures the spaceborne UPF2.

[0538] Step 1009 in this embodiment is similar to step 906 in the foregoing embodiment shown in FIG. 9, and details are not described here again.

[0539] 1010、P-CSCF1 sends 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, i.e., the service flow information between UE1 and the ground AGW1. In response to the second service flow information, SMF1 performs step 1011.

[0541] 1011、SMF1 configures the spaceborne UPF1.

[0542] Step 1011 in this embodiment is similar to step 909 in the foregoing embodiment shown in FIG. 9, and details are not described here again.

[0543] In the embodiments of the present application, when the inter-satellite path changes from available to unavailable, the ground path can be switched, thereby guaranteeing the continuity of the call service and preventing the call service from being interrupted.

[0544] It should be understood that the embodiment shown in FIG. 10 takes the path state between the satellite-borne AGW1 and the satellite-borne AGW2 as an example, which changes from the available state to the unavailable state. In actual application, the path state between the satellite-borne AGW1 and the satellite-borne AGW2 can also change from the unavailable state to the available state, at this time, the second indication information in the step 1004 and the step 1006 in the embodiment shown in FIG. 10 is used to instruct the third terminal device or the fourth terminal device to switch from the second path to the first path. Wherein, if the satellite-borne AGW and the satellite-borne UPF retain the configuration information of the first path, only the UE needs to be notified to switch the path, otherwise, the step 1009 and the step 1011 need to be re-executed.

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

[0546] 1101. The P-CSCF1 obtains the identification information of the satellite-borne AGW1.

[0547] The step 1101 in the embodiment is similar to the step 901 in the embodiment shown in the foregoing FIG. 9, and details are not described here.

[0548] 1102. The P-CSCF1 selects and configures the ground AGW1.

[0549] The step 1102 in the embodiment is similar to the step 703 in the embodiment shown in the foregoing FIG. 7, and details are not described here.

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

[0551] The call request includes the IP address of the satellite-borne AGW1 and the IP address of the ground AGW1.

[0552] 1104. P-CSCF 2 selects and configures ground AGW 2.

[0553] Step 1005 in this embodiment is similar to step 706 in the foregoing embodiment shown in FIG. 7, and details are not repeated here.

[0554] 1105. P-CSCF 2 sends path configuration information to spaceborne AGW 2.

[0555] The path configuration information includes an IP address of spaceborne AGW 1 and an IP address of ground AGW 2. The IP address of spaceborne AGW 1 is used to indicate the third path, and the IP address of ground AGW 2 is used to indicate the fourth path. The third path is a path between the third terminal device and the fourth terminal device through the third network element and the fourth network element, i.e., a path between UE 1 and UE 2 through spaceborne AGW 1 and spaceborne AGW 2; the fourth path is a path between the third network element and the fourth network element through the ground access gateway, i.e., a path between spaceborne AGW 1 and spaceborne AGW 2 through ground AGW 1 and ground AGW 2.

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

[0557] Optionally, P-CSCF 2 also sends fifth indication information to spaceborne AGW 2, the fifth indication information being used to instruct spaceborne AGW 2 to use the third path or the fourth path to transmit data according to the path status of the third path and the fourth path.

[0558] Optionally, the P-CSCF 2 also sends a path selection policy to the spaceborne AGW 2, the path selection policy being used by the spaceborne AGW 2 to select a path, the path selection policy comprising one or more of an initial path indication, a path priority, a path with low latency, a path with low packet loss, a path latency threshold, and a path packet loss threshold. The initial path indication is used to indicate an initial path used by the spaceborne AGW 2, and the path priority is used to indicate a preferred path between the third path and the fourth path. For example, if the P-CSCF 2 receives an indication from the SMF 2 that the third path (i.e., the inter-satellite path) is available, the P-CSCF 2 can indicate in the call signaling that the spaceborne AGW 2 initially uses the third path. The path latency threshold and the path packet loss threshold included in the path selection policy are used to monitor the availability of the path, i.e., when the path latency and the path packet loss are respectively less than the path latency threshold and the path packet loss threshold, it indicates that the path is available. When the path is available, the path is selected according to the path priority. For example, assuming that both the third path and the fourth path are available, and the third path has a higher priority, the third path is selected. For another example, assuming that the path selection policy indicates to select a path with low latency, and according to the path monitoring, the fourth path has a lower latency, the fourth path is selected.

[0559] Optionally, the P-CSCF 2 also sends sixth indication information to the spaceborne AGW 2, the sixth indication information being used to instruct the spaceborne AGW 2 to perform path monitoring on the third path and / or the fourth path, so as to obtain a path status of the third path and / or the fourth path.

[0560] 1106. The P-CSCF 2 sends call signaling to the UE 2, and correspondingly, the UE 2 receives the call signaling from the P-CSCF 2.

[0561] The call signaling comprises an IP address of the spaceborne AGW 2. For the UE 2, the UE 2 needs to send a data packet sent to the UE 1 to the spaceborne AGW 2 according to the IP address of the spaceborne AGW 2, and the spaceborne AGW 2 determines a transmission path of the data packet.

[0562] 1107. The P-CSCF 2 sends third service flow information to the SMF 2, and correspondingly, the SMF 2 receives the third service flow information from the P-CSCF 2.

[0563] 1108. The SMF 2 configures the spaceborne UPF 2.

[0564] The steps 1107 to 1108 in this embodiment are similar to the steps 905 to 906 in the foregoing embodiment shown in FIG. 9, and details are not described herein again.

[0565] 1109. The P-CSCF 2 sends a call response to the P-CSCF 1, and correspondingly, the P-CSCF 1 receives the call response from the P-CSCF 2.

[0566] The call response is a response message corresponding to the call request in step 1103. The response message carries information of the ground path and the inter-satellite path. The information of the inter-satellite path includes the IP address of the on-board AGW2. The information of the ground path includes the address of the ground AGW2. The message can also indicate to establish the ground path and the inter-satellite path simultaneously.

[0567] 1110, the P-CSCF1 sends the path configuration information to the on-board AGW1.

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

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

[0570] 1113, the SMF1 configures the on-board UPF1.

[0571] The steps 1112 to 1113 in this embodiment are similar to the steps 909 to 910 in the foregoing embodiment shown in FIG. 9, and details are not described here.

[0572] Optionally, the embodiment shown in FIG. 11 further includes step 1100a. The step 1100a can be performed before the step 1101.

[0573] 1100a, the P-CSCF1 sends a path state subscription request to the on-board AGW1, and correspondingly, the on-board AGW1 receives the path state subscription request from the P-CSCF1.

[0574] Optionally, the embodiment shown in FIG. 11 further includes step 1100b. The step 1100b can be performed after the step 1100a.

[0575] 1100b, the on-board AGW1 sends a path state notification message to the P-CSCF1, and correspondingly, the P-CSCF1 receives the path state notification message from the on-board AGW1.

[0576] Optionally, the embodiment shown in FIG. 11 further includes step 1100c. The step 1100c can be performed before the step 1101.

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

[0578] Optionally, the embodiment shown in FIG. 11 further includes step 1100d. Step 1100d can be performed after step 1100c.

[0579] 1100d. The spaceborne AGW 2 sends a path status notification message to the P-CSCF 2, and correspondingly, the P-CSCF 2 receives the path status notification message from the spaceborne AGW 2.

[0580] Steps 1100a to 1100d in the embodiments of the present application are similar to steps 900a to 900d in the foregoing embodiment of FIG. 9, and will not be described here again.

[0581] The communication method in the embodiments of the present application is described above, and the communication apparatus in the embodiments of the present application is described below. Referring to FIG. 12, the communication apparatus 1200 can be used to perform the process performed by the session management network element (SMF1 or SMF2) in the embodiments shown in FIGS. 5 to 11, and details can be referred to the related description in the foregoing method embodiments. The communication apparatus 1200 can be a network device, or a component or apparatus (such as a processor, a chip, or a chip system) applied to a network device, or a logic module or software capable of realizing all or part of the functions of the network device.

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

[0583] The processing module 1202 is configured to perform data processing. The interface module 1201 can realize corresponding communication functions. The interface module 1201 can also be referred to as a communication interface or a communication module.

[0584] Optionally, the communication apparatus 1200 can further include a storage module, which can be used to store program codes, program instructions and / or data. The processing module 1202 can read the instructions and / or data in the storage module, so that the communication apparatus 1200 realizes the foregoing method embodiments.

[0585] The communication apparatus 1200 can be used to perform the actions performed by the session management network element in the foregoing method embodiments. For example, the communication apparatus 1200 can be the session management network element or a communication module in the session management network element, or a circuit or chip responsible for communication functions in the session management network element. The communication apparatus 1200 can be the session management network element or a component configurable to the session management network element. The processing module 1202 is configured to perform operations related to processing at the session management network element side in the foregoing method embodiments. The interface module 1201 is configured to perform operations related to receiving at the session management network element side in the foregoing method embodiments.

[0586] Optionally, the interface module 1201 can include a sending module and a receiving module. The sending module is configured to perform the sending operations in the above method embodiments. The receiving module is configured to perform the receiving operations in the above method embodiments.

[0587] It should be noted that the communication apparatus 1200 can include a sending module, but not a receiving module. Alternatively, the communication apparatus 1200 can include a receiving module, but not a sending module. Specifically, whether the sending module and the receiving module are included in the communication apparatus 1200 can depend on whether the sending action and the receiving action are included in the above schemes performed by the communication apparatus 1200. For example, the communication apparatus 1200 is configured to perform the actions performed by the session management network element in the above embodiments shown in FIGS. 5-11. Details can be referred to the related description in the above embodiments shown in FIGS. 5-11, which will not be repeated here.

[0588] For example, the communication apparatus 1200 is configured to perform the following schemes.

[0589] The interface module 1201 is configured to receive a first request message, where the first request message includes identification information of a first network element, and the first network element is deployed on a first non-ground network device.

[0590] The processing module 1202 is configured to acquire path state information based on the identification information of the first network element, where the path state information is used to indicate a path state between the first network element and a second network element, the second network element is deployed on a second non-ground network device, and the first network element and the second network element are both user plane function network elements.

[0591] In a possible implementation, the interface module 1201 is further configured to receive a path state notification message, where the path state notification message includes path states between the second network element and multiple network elements.

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

[0593] In another possible implementation, the interface module 1201 is further configured to send a query request message, where the query request message includes the identification information of the first network element, and the identification information of the first network element is used to acquire the path state between the first network element and the second network element.

[0594] The interface module 1201 is further configured to receive a first response message, where the first response message is a response message of the query request message, and the first response message is used to indicate the path state information.

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

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

[0597] In another possible implementation, the first request message further includes tunnel information of the first network element and an Internet Protocol, IP, address of the first terminal device, and the interface module 1201 is further configured to send a first splitting rule, where the first splitting rule is used to instruct 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 first data packet has the IP address of the first terminal device as a destination address, the first data packet is obtained by the second network element from a second terminal device, the first network element provides services for the first terminal device, and the second network element provides services for the second terminal device.

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

[0599] In another possible implementation, the interface module 1201 is further configured to send a second splitting rule, where the second splitting rule is used to instruct the second network element to send the first data packet to a session anchor, the first data packet has the IP address of the first terminal device as the destination address, the first data packet is obtained by the second network element from the second terminal device, the first network element provides services for the first terminal device, the second network element provides services for the second terminal device, and the session anchor is deployed in the first ground network.

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

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

[0602] In another possible implementation, the interface module 1201 is specifically configured to send the first indication information when the first splitting rule and the second splitting rule are sent.

[0603] In another possible implementation, the interface module 1201 is further configured to receive first information, where the first information is used to instruct that the path status between the first network element and the second network element changes, or is used to instruct to switch a transmission path between the first network element and the second network element.

[0604] The interface module 1201 is specifically configured to send the first splitting rule according to the first information.

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

[0606] In another possible implementation, the interface module 1201 is further configured to receive second information, the second information including service flow information between the second terminal device and a ground access gateway, the ground access gateway being deployed in a second ground network, and the ground access gateway and the second network element transmitting data through a session anchor;

[0607] The interface module 1201 is specifically configured to send, in response to the second information, a third split rule and a fourth split rule, the third split rule being used to instruct the second network element to send a third data packet to the session anchor, the third data packet being a data packet sent by the second terminal device to the ground access gateway, and the fourth split rule being used to instruct the second network element to send a fourth data packet from the session anchor to the second terminal device, the fourth data packet being a data packet sent by the ground access gateway to the second terminal device.

[0608] In another possible implementation, the interface module 1201 is further configured to receive third information, the third information being used to instruct that a path state between the first network element and the second network element changes;

[0609] 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, the interface module 1201 is configured to send, in response to the third information, a path available indication;

[0610] 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, the interface module 1201 is configured to send, in response to the third information, a path unavailable indication.

[0611] In another possible implementation, the first request message further includes an IP address of the second terminal device and an IP address of the ground access gateway, and the interface module 1201 is further configured to send a third split rule, the third split rule being used to instruct the second network element to send a third data packet from the session anchor to the second terminal device, the third data packet being a data packet sent by the ground access gateway to the second terminal device, the ground access gateway being deployed in a second ground network, the session anchor being deployed in a first ground network, and the ground access gateway and the second network element transmitting the third data packet through the session anchor.

[0612] It should be understood that specific processes in which the modules perform the corresponding processes described above are described in detail in the method embodiments described above, and thus are not described herein again 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 circuit. The interface module 1201 can be implemented by a transceiver or transceiver-related circuit. The interface module 1201 can also be referred to as a communication module or a communication interface. The storage module can be implemented by at least one memory.

[0614] Another structural diagram of a communication apparatus according to the embodiments of the present application is shown below. Please refer to FIG. 13. The communication apparatus can be used to execute the process performed by the first proxy call session control function network element (P-CSCF1) in the embodiments shown in FIG. 5 to FIG. 11. Please refer to the relevant description in the foregoing method embodiments.

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

[0616] The processing module 1302 is configured to perform data processing. The interface module 1301 can implement corresponding communication functions. The interface module 1301 can also be referred to as a communication interface or a communication module.

[0617] Optionally, the communication apparatus 1300 can further include a storage module, which can be configured to store program codes, program instructions and / or data. The processing module 1302 can read the instructions and / or data in the storage module, so that the communication apparatus 1300 implements the foregoing method embodiments.

[0618] The communication apparatus 1300 can be configured to execute the actions performed by the first proxy call session control function network element in the foregoing method embodiments. For example, the first proxy call session control function network element or a communication module in the first proxy call session control function network element, or a circuit or chip responsible for communication functions in the first proxy call session control function network element. The communication apparatus 1300 can be the first proxy call session control function network element or a component configurable to the first proxy call session control function network element. The processing module 1302 is configured to perform operations related to processing on the side of the first proxy call session control function network element in the foregoing method embodiments. The interface module 1301 is configured to perform operations related to receiving on the side of the first proxy call session control function network element in the foregoing method embodiments.

[0619] Optionally, the interface module 1301 can include a sending module and a receiving module. The sending module is configured to perform the sending operations in the foregoing method embodiments. The receiving module is configured to perform the receiving operations in the foregoing method embodiments.

[0620] It should be noted that the communication apparatus 1300 can include the sending module and not include the receiving module. Alternatively, the communication apparatus 1300 can include the receiving module and not include the sending module. Whether the communication apparatus 1300 includes the sending module or the receiving module can depend on whether the communication apparatus 1300 performs the sending action or the receiving action in the above-mentioned schemes. For example, the communication apparatus 1300 is configured to perform the actions performed by the first proxy call session control function network element in the embodiments of FIG. 5 to FIG. 11. Details can be referred to the related description in the embodiments of FIG. 5 to FIG. 11, which will not be repeated here.

[0621] For example, the communication apparatus 1300 is configured to perform the following scheme.

[0622] The processing module 1302 is configured to obtain identification information of a third network element, the third network element being deployed in a first non-terrestrial network device.

[0623] The interface module 1301 is configured to send the identification information of the third network element, the identification information of the third network element being used to obtain a transmission path between a third terminal device and a fourth terminal device, the third network element providing service for the third terminal device.

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

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

[0626] The interface module 1301 is further configured to receive a fourth response message, the fourth response message being a response message of the third request message, the fourth response message including the identification information of the third network element.

[0627] In another possible implementation, the third response message includes indication information of a first path and / or indication information of a second path, the first path being a path between the third terminal device and the fourth terminal device through the third network element and a fourth network element, the second path being a path between the third terminal device and the fourth terminal device through a session anchor or a ground access gateway, the fourth network element providing service for the fourth terminal device, the session anchor being deployed in a first ground network, the ground access gateway being deployed in a second ground network, wherein the session anchor includes a session anchor providing service for the third terminal device and a session anchor providing service for the fourth terminal, and the ground access gateway includes a ground access gateway providing service for the third terminal device and a ground access gateway providing service for the fourth terminal.

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

[0629] In another possible implementation, the interface module 1301 is further configured to send call signaling, the call signaling being used to indicate the first path and / or the second path.

[0630] The call signaling comprises any one of the following: an IP address of the fourth terminal device, an IP address of a ground access gateway which is a ground access gateway serving the third terminal device, and an IP address of the third network element.

[0631] Case A: when the third response message indicates the first path and the third network element is a user plane function network element, the IP address of the fourth terminal device is included in the call signaling. In this case, the third terminal device directly sends the session data packet to the fourth terminal device through the IP address of the fourth terminal device.

[0632] Case B: when the fourth response message indicates the first path and the third network element is an access gateway, the IP address of the third network element is included in the call signaling. In this case, the third terminal device sends the session data packet to the fourth terminal device by first sending the session data packet to the third network element, and then sending the session data packet to the fourth terminal device by the third network element.

[0633] Case C: when the fourth response message indicates the second path and the second path is a path between the third terminal device and the fourth terminal device through a session anchor point, the IP address of the fourth terminal device is included in the call signaling. In this case, the third terminal device directly sends the session data packet to the fourth terminal device through the IP address of the fourth terminal device.

[0634] Case D: when the fourth response message indicates the second path and the second path is a path between the third terminal device and the fourth terminal device through a ground access gateway, the IP address of the ground access gateway which is a ground access gateway serving the third terminal device is included in the call signaling. In this case, the third terminal device sends the session data packet to the fourth terminal device by first sending the session data packet to the ground access gateway serving the third terminal device, and then sending the session data packet to the fourth terminal device by the ground access gateway.

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

[0636] In another possible implementation, the interface module 1301 is further configured to receive third information, where the third information is used to indicate that a path state of the first path or the second path changes.

[0637] The interface module 1301 is further configured to send fourth information, where the fourth information is used to indicate that the first path is switched to the second path, or is used to indicate that the second path is switched to the first path.

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

[0639] Or, when the fourth information is used to indicate that the first path is switched to the second path, and the second path is a path between the third terminal device and the fourth terminal device through a session anchor point, the fourth information includes an IP address of the third terminal device.

[0640] Or, 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 tunnel information of the third network element and an IP address of the third terminal device, and the third network element provides services for the third terminal device.

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

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

[0643] When the target path is the above case A, the second indication information is used to instruct the third terminal device to send session data packets to the fourth terminal device directly through an IP address of the fourth terminal device.

[0644] When the target path is the above case B, the second indication information is used to instruct the third terminal device to send session data packets to the fourth terminal device to the third network element first, and then send the session data packets to the fourth terminal device by the third network element.

[0645] When the target path is case C, the second indication 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, the second indication information is used to instruct the third terminal device to send the session data packet to the ground access gateway serving the third terminal device first, and then send the session data packet to the fourth terminal device by the ground access gateway.

[0647] In another possible implementation, the interface module 1301 is further configured to send fifth information in the path switching process, and 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 further includes third indication information, and the third indication information is used to instruct the third terminal device to use the first path or the second path to transmit data according to the path state of the first path and / or the second path.

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

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

[0651] In another possible implementation, the third network element is an access gateway, the third response message includes information of the third path and / or information of the fourth path, the information of the third path includes an IP address of the fourth network element, the fourth network element is deployed in the second non-terrestrial network device, the fourth network element is an access gateway, the fourth network element serves the fourth terminal device, the information of the fourth path includes an IP address of the ground access gateway, the ground access gateway is deployed in the second ground network, the third path is a path between the third terminal device and the fourth terminal device through the third network element and the fourth network element, and the fourth path is a path between the third terminal device and the fourth terminal device through the third network element and the ground access gateway.

[0652] In another possible implementation, the interface module 1301 is further configured to send fifth indication information, and the fifth indication information is used to instruct the third network element to use the third path or the fourth path to transmit data according to the path state of the third path and / or the fourth path.

[0653] In another possible implementation, the interface module 1301 is further configured to send a path selection policy, the path selection policy comprising one or more of an initial path indication, a path priority, a path with a low latency, a path with a low packet loss rate, a path latency threshold, and a path packet loss rate threshold.

[0654] The interface module 1301 is further configured to send sixth indication information, the sixth indication information being used to indicate that the third network element monitors the path status of the third path and / or the fourth path.

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

[0656] It should be understood that the specific processes in which the modules perform the corresponding processes described above have been described in detail in the method embodiments, and thus are not described herein again 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 circuit. The interface module 1301 can be implemented by a transceiver or transceiver-related circuit. The interface module 1301 can also be referred to as a communication module or a communication interface. The storage module can be implemented by at least one memory.

[0658] Another structural schematic diagram of a communication apparatus according to an embodiment of the present application is shown below. Please refer to FIG. 14. The communication apparatus can be used to execute the processes performed by the second proxy call session control function network element (P-CSCF2) in the embodiments shown in FIGS. 5 to 11, and details can be referred to the related descriptions in the foregoing method embodiments.

[0659] The communication apparatus 1400 comprises an interface module 1401. Optionally, the communication apparatus 1400 further comprises a processing module 1402.

[0660] The processing module 1402 is configured to perform data processing. The interface module 1401 can implement corresponding communication functions. The interface module 1401 can also be referred to as a communication interface or a communication module.

[0661] Optionally, the communication apparatus 1400 further comprises a storage module, which can be used to store program codes, program instructions and / or data. The processing module 1402 can read the instructions and / or data in the storage module, so that the communication apparatus 1400 implements the foregoing method embodiments.

[0662] The communication apparatus 1400 can be configured to perform the actions of the second proxy call session control function network element in the above method embodiments. For example, the second proxy call session control function network element or a communication module in the second proxy call session control function network element, or a circuit or chip responsible for communication function in the second proxy call session control function network element. The communication apparatus 1400 can be the second proxy call session control function network element or a component configurable to the second proxy call session control function network element. The processing module 1402 is configured to perform the processing related operations of the second proxy call session control function network element side in the above method embodiments. The interface module 1401 is configured to perform the receiving related operations of the second proxy call session control function network element side in the above method embodiments.

[0663] Optionally, the interface module 1401 can include a sending module and a receiving module. The sending module is configured to perform the sending operations in the above method embodiments. The receiving module is configured to perform the receiving operations in the above method embodiments.

[0664] It should be noted that the communication apparatus 1400 can include a sending module and not include a receiving module. Alternatively, the communication apparatus 1400 can include a receiving module and not include a sending module. Specifically, whether the communication apparatus 1400 includes a sending action and a receiving action can be determined according to the above scheme performed by the communication apparatus 1400. For example, the communication apparatus 1400 is configured to perform the actions of the second proxy call session control function network element in the above embodiments shown in FIG. 5 to FIG. 11. Details can be referred to the related description in the above embodiments shown in FIG. 5 to FIG. 11, which will not be described here.

[0665] For example, the communication apparatus 1400 is configured to perform the following scheme:

[0666] The interface module 1401 is configured to receive identification information of a third network element, the identification information of the third network element being used to obtain a transmission path between a third terminal device and a fourth terminal device, the third network element providing a service for the third terminal device, the third network element being a user plane function network element or an access gateway, and the third network element being deployed in a first non-terrestrial network device.

[0667] The processing module 1402 is configured to generate a third response message.

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

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

[0670] The interface module 1401 is further configured to receive a fourth response message, the fourth response message being a response message of the second request message, and the fourth response message being used to indicate a path establishment state between the third network element and a fourth network element, the fourth network element providing service for a fourth terminal device, and the fourth network element being deployed in the second non-terrestrial network device.

[0671] The processing module 1402 is further configured to determine a transmission path between the third terminal device and the fourth terminal device according to the path establishment state between the third network element and the network element.

[0672] In another possible implementation, the third response message includes indication information of the first path or indication information of the second path, the first path being a path between the third terminal device and the fourth terminal device through the third network element and the fourth network element, the second path being a path between the third terminal device and the fourth terminal device through the session anchor or the ground access gateway, the fourth network element providing service for the fourth terminal device, and the session anchor being deployed in the first ground network and the ground access gateway being deployed in the second ground network.

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

[0674] Or, if the path establishment state between the third network element and the fourth network element is the failed establishment state, the second response message includes the 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 tunnel information of the third network element and an 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 an IP address of the third network element; and the indication information of the second path includes an IP address of the ground access gateway.

[0676] In another possible implementation, the interface module 1401 is further configured to send a call signaling, the call signaling including the IP address of the third terminal device and / or the IP address of the ground access gateway; or, when the fourth network element is an access gateway, the call signaling including an IP address of the fourth network element and / or the IP address of the ground access gateway.

[0677] In another possible implementation, the interface module 1401 is further configured to receive third information, the third information being used to indicate that a path state of the first path or the second path changes.

[0678] The interface module 1401 is further configured to send fourth information, the fourth information being used to indicate that the first path is switched to the second path, or being used to indicate that the second path is switched to the first path.

[0679] In a possible implementation, when the fourth information is used to indicate switching the first path to the second path, the fourth information comprises an IP address of a ground access gateway, and the ground access gateway is deployed in the second ground network.

[0680] Or, when the fourth information indicates switching the second path to the first path, and the third network element and the fourth network element are both user plane function network elements, the fourth information comprises tunnel information of the third network element and an IP address of the third terminal device, and the third network element provides services for the third terminal device.

[0681] Or, when the fourth information indicates switching the second path to the first path, and the third network element and the fourth network element are both access gateways, the fourth information comprises an IP address of the fourth network element.

[0682] In a possible implementation, the interface module 1401 is further configured to send second indication information, and the second indication information is used to indicate that the fourth terminal device switches the first path to the second path or switches the second path to the first path.

[0683] In a possible implementation, the interface module 1401 is further configured to send fifth information, and the fifth information comprises service flow information between the fourth terminal device and a ground access gateway.

[0684] In a possible implementation, the call signaling further comprises third indication information, and the third indication information is used to indicate that the fourth terminal device uses the first path or the second path to transmit data according to a path state of the first path and / or the second path.

[0685] In a possible implementation, the call signaling further comprises a path selection policy, and the path selection policy comprises one or more of the following: initial path indication, path priority, selecting a path with low latency, selecting a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

[0686] In a possible implementation, the call signaling further comprises fourth indication information, and the fourth indication information is used to instruct the fourth terminal device to perform path monitoring to obtain a path state of the first path and / or the second path.

[0687] In a possible implementation, the fourth network element is an access gateway, the third response message comprises information of a third path and / or information of a fourth path, the information of the third path comprises an IP address of a third network element, the third network element is deployed in a second non-ground network device, the third network element is an access gateway, the information of the fourth path comprises an IP address of a ground access gateway, the ground access gateway is deployed in a second ground network, the third path is a path between the third network element and the fourth network element, and the fourth path is a path between the fourth network element and the ground access gateway.

[0688] In another possible implementation, the interface module 1401 is further configured to send fifth indication information, where the fifth indication information 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, the interface module 1401 is further configured to send path selection policy, where the path selection policy includes one or more of the initial path indication, the path priority, the path with low latency, the path with low packet loss rate, the path latency threshold, and the path packet loss rate threshold.

[0690] The interface module 1401 is further configured to send sixth indication information, where the sixth indication information 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 further configured to determine the transmission path based on path status information, where the path status information is determined based on the identification information of the third network element, and 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 for the fourth terminal device.

[0692] It should be understood that the specific processes in which the various modules perform the corresponding processes described above have been described in detail in the method embodiments described above, and thus are not described herein again 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 circuit. The interface module 1401 can be implemented by a transceiver or transceiver-related circuit. The interface module 1401 can also be referred to as a communication module or a communication interface. The storage module can be implemented by at least one memory.

[0694] Another structural schematic diagram of the communication apparatus according to the embodiments of the present application is shown below. Please refer to FIG. 15. The communication apparatus can be used to execute the processes performed by the first network element, the second network element, the third network element, or the fourth network element (the satellite borne UPF or the satellite borne AGW) in the embodiments shown in FIGS. 5 to 11. For details, please refer to the related descriptions in the foregoing method embodiments.

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

[0696] The processing module 1502 is configured to perform data processing. The interface module 1501 can implement corresponding communication functions. The interface module 1501 can also be referred to as a communication interface or a communication module.

[0697] Optionally, the communication apparatus 1500 further includes a storage module, which can be used to store program codes, program instructions and / or data. The processing module 1502 can read the instructions and / or data in the storage module, so that the communication apparatus 1500 implements the foregoing method embodiments.

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

[0699] Optionally, the interface module 1501 can include a sending module and a receiving module. The sending module is configured to perform the sending operations in the foregoing method embodiments. The receiving module is configured to perform the receiving operations in the foregoing method embodiments.

[0700] It should be noted that the communication apparatus 1500 can include the sending module and not include the receiving module. Alternatively, the communication apparatus 1500 can include the receiving module and not include the sending module. Specifically, whether the sending module and the receiving module are included in the communication apparatus 1500 depends on whether the sending actions and the receiving actions are included in the foregoing schemes performed by the communication apparatus 1500. For example, the communication apparatus 1500 is configured to perform the actions performed by the satellite UPF or the satellite AGW in the foregoing embodiments shown in FIGS. 5-11. Details can be referred to the related descriptions in the foregoing embodiments shown in FIGS. 5-11, which are not described here in detail.

[0701] For example, the communication apparatus 1500 is configured to perform the following schemes:

[0702] The processing module 1502 is configured to determine path state information, the path state information being used to indicate a path state between a third network element and a fourth network element, the third network element being deployed at a first non-terrestrial network device, the fourth network element being deployed at a second non-terrestrial network device, the third network element and the fourth network element both being user plane function network elements, or the third network element and the fourth network element both being access gateways.

[0703] The interface module 1501 is configured to transmit the path state information.

[0704] The processing module 1502 is further configured to determine a transmission path between a third terminal device and a fourth terminal device according to the path state information, the first network element providing services for the first terminal device, and the second network element providing services for the second terminal device.

[0705] In a possible implementation, the transmission path comprises: a first path and / or a second path, the first path being a 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 being a path between the third terminal device and the fourth terminal device through the session anchor or the ground access gateway, the session anchor being deployed in the first ground network, or the ground access gateway being deployed in the second ground network.

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

[0707] In another possible implementation, the interface module 1501 is further configured to receive first indication information, the first indication information being used to indicate that the first offloading rule or the second offloading rule is used according to the path state information.

[0708] The processing module 1502 is further configured to determine the transmission path of the first data packet according to the first offloading rule or the second offloading rule in response to the first indication information.

[0709] In another possible implementation, the processing module 1502 is specifically configured to determine that the transmission path is the first path if the path state of the first path is an available state.

[0710] Or, determine that the transmission path is the second path if the path state of the first path is an unavailable state.

[0711] In another possible implementation, when the third network element and the fourth network element are access gateways, the transmission path comprises: a third path and / or a fourth path, the third path being a path between the third network element and the fourth network element, and the fourth path being a path between the third network element and the fourth network element through the ground access gateway, the ground access gateway being deployed in the second ground network.

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

[0713] In another possible implementation, the interface module 1501 is further configured to receive fifth indication information, where the fifth indication information is used to instruct the third network element to transmit data using the third path or the fourth path according to path states of the third path and / or the fourth path.

[0714] In another possible implementation, the interface module 1501 is further configured to receive a path selection policy, where the path selection policy includes one or more of initial path indication, path priority, path with low latency, 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 configured to receive a path state subscription request, where the path state subscription request is used to request sending of a path state notification message when a path state between the fourth network element and any network element of the at least one network element changes.

[0716] The interface module 1501 is specifically configured to send the path state notification message, where the path state notification message is used to indicate the path state between the fourth network element and any network device of the at least one network element, and the path state notification message includes the path state information.

[0717] In another possible implementation, the interface module 1501 is further configured to receive a query request message, where the query request message includes identification information of the third network element, and the query request message is used to request querying of a path state between the third network element and the fourth network element.

[0718] The interface module 1501 is further configured to send a first response message, where the first response message is a response message of the query request message, and the first response message is used to indicate the path state information.

[0719] In another possible implementation, the interface module 1501 is further configured to send first information, where the first information is used to indicate that a path state between the first network element and the second network element changes.

[0720] It should be understood that specific processes in which the various modules perform the corresponding processes described above are described in detail in the method embodiments described above, and thus are not described herein again 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 circuit. The interface module 1501 can be implemented by a transceiver or transceiver-related circuit. The interface module 1501 can also be referred to as a communication module or a communication interface. The storage module can be implemented by at least one memory.

[0722] Another structure of the communication apparatus in the embodiments of the present application is shown below. Please refer to FIG. 16. The communication apparatus can be used to perform the processes performed by the terminal device (UE1 or UE2) in the embodiments shown in FIG. 5 to FIG. 11. For details, please refer to the related descriptions in the foregoing method embodiments.

[0723] The communication apparatus 1600 comprises an interface module 1601. Optionally, the communication apparatus 1600 comprises a processing module 1602.

[0724] The processing module 1602 is configured to perform data processing. The interface module 1601 can implement corresponding communication functions. The interface module 1601 can also be referred to as a communication interface or a communication module.

[0725] Optionally, the communication apparatus 1600 can further comprise a storage module, which can be configured to store program codes, program instructions and / or data. The processing module 1602 can read the instructions and / or data in the storage module, so that the communication apparatus 1600 can implement the foregoing method embodiments.

[0726] The communication apparatus 1600 can be configured to perform the actions performed by the terminal device in the foregoing method embodiments. For example, the communication apparatus 1600 can be the terminal device or a communication module in the terminal device, or a circuit or chip responsible for communication functions in the terminal device. The communication apparatus 1600 can be the terminal device or a component configurable to the terminal device. The processing module 1602 is configured to perform operations related to processing of the terminal device in the foregoing method embodiments. The interface module 1601 is configured to perform operations related to receiving of the terminal device in the foregoing method embodiments.

[0727] Optionally, the interface module 1601 can comprise a sending module and a receiving module. The sending module is configured to perform the sending operations in the foregoing method embodiments. The receiving module is configured to perform the receiving operations in the foregoing method embodiments.

[0728] It should be noted that the communication apparatus 1600 can comprise the sending module and not comprise the receiving module. Alternatively, the communication apparatus 1600 can comprise the receiving module and not comprise the sending module. Whether the communication apparatus 1600 comprises the sending module and the receiving module can depend on whether the communication apparatus 1600 performs the sending actions and the receiving actions in the foregoing schemes. For example, the communication apparatus 1600 is configured to perform the actions performed by the terminal device in the embodiments shown in FIG. 5 to FIG. 11. For details, please refer to the related descriptions in the foregoing embodiments shown in FIG. 5 to FIG. 11, which will not be described herein.

[0729] For example, the communication apparatus 1600 is configured to perform the following schemes:

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

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

[0732] In a possible implementation, the indication information of the first path includes an IP address of the third network element, and the indication information of the second path includes an IP address of the ground access gateway, the third network element providing services for the third terminal device.

[0733] In another possible implementation, the interface module 1601 is further configured to receive third indication information, the third indication information being used to indicate that the path of the second data packet is determined according to the state of the first path or the second path.

[0734] In another possible implementation, the interface module 1601 is further configured to receive fourth indication information, the fourth indication information being used to indicate that the state of the first path or the second path is monitored.

[0735] In another possible implementation, the interface module 1601 is further configured to receive a path selection policy, the path selection policy including one or more of initial path indication, path priority, path with low latency, 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 further configured to monitor the state of the first path and / or the second path.

[0737] It should be understood that the specific processes in which the modules perform the corresponding processes described above have been described in detail in the method embodiments described above, and thus will not be described herein again for the sake of brevity.

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

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

[0740] Next, a communication apparatus provided by an embodiment of the present application is introduced. Referring to FIG. 17, FIG. 17 is a structural schematic diagram of the communication apparatus provided by the embodiment of the present application. The communication apparatus can be a network device or a terminal device in the above-mentioned method embodiments, and can also be a chip, a chip system, or a processor, etc. supporting the network device or the terminal device to implement the above-mentioned method. The communication apparatus can be used to implement the method described in the above-mentioned method embodiments, and the specific implementation can be referred to the description in the above-mentioned method embodiments.

[0741] The communication apparatus can include one or more processors 1701. The processor 1701 is connected with a memory 1702, an input an...

Claims

1. A communication method characterized by comprising: The method is applied to a session management function network element, and the method comprises: receiving a first request message, wherein the first request message comprises identification information of a first network element, and the first network element is deployed on a first non-ground network device; obtaining path state information based on the identification information of the first network element, wherein the path state information is used to indicate a path state between the first network element and a second network element, the second network element is deployed on a second non-ground network device, and the first network element and the second network element are both user plane function network elements.

2. The method of claim 1, wherein, The method further comprises: receiving a path state notification message, wherein the path state notification message comprises a path state between the second network element and multiple network elements; The method further comprises: determining the path state information based on the identification information of the first network element and the path state notification message.

3. The method of claim 1, wherein, The method further comprises: sending a query request message, wherein the query request message comprises the identification information of the first network element, the identification information of the first network element is used to obtain the path state between the first network element and the second network element; receiving a first response message, wherein the first response message is a response message of the query request message, and the first response message is used to indicate the path state information.

4. The method according to any one of claims 1 to 3, characterized in that, The method further comprises: sending a second response message, wherein the second response message is a response message of the first request message; wherein if the path state information indicates that the path state between the first network element and the second network element is an available state, the second response message comprises tunnel information of the second network element; or, if the path state information indicates that the path state between the first network element and the second network element is an unavailable state, the second response message comprises a path unavailable indication.

5. The method according to any one of claims 1 to 4, characterized in that, The first request message further comprises tunnel information of the first network element and an Internet Protocol (IP) address of a first terminal device, and the method further comprises: sending a first split rule, wherein the first split rule is used to indicate that the second network element sends a first data packet to the first network element according to the tunnel information of the first network element, the first data packet is obtained by the second network element from a second terminal device, the first data packet has a destination address of the IP address of the first terminal device, the first network element provides services for the first terminal device, and the second network element provides services for the second terminal device.

6. The method of claim 5, wherein, The sending of the first split rule comprises: if the path state information indicates that the path state between the first network element and the second network element is an available state, the first split rule is sent.

7. The method according to any one of claims 1 to 4, characterized in that, The first request message further comprises tunnel information of the first network element and IP identification information of the first terminal device, and the method further comprises: sending a first message, the first message comprising indication information and a first split rule, the indication information being used to indicate that the second network element performs splitting according to the first split rule when a path state between the first network element and the second network element is an available state, the first split rule being used to indicate that the second network element sends a first data packet to the first network element through tunnel information of the first network element, a destination address of the first data packet being identification information of the first terminal device, the first data packet being obtained by the second network element from a second terminal device, the first network element providing service for an IMS session or IMS connection of the first terminal device, and the second network element providing service for the second terminal device; receiving an establishment success indication when the path state is the available state; or receiving a path unavailable indication when the path state is unavailable.

8. The method according to any one of claims 1 to 5, characterized in that, The method further comprises: sending a second split rule, the second split rule being used to indicate that the second network element sends the first data packet to a session anchor point, a destination address of the first data packet being an IP address of the first terminal device, the first data packet being obtained by the second network element from the second terminal device, the first network element providing service for the first terminal device, the second network element providing service for the second terminal device, and the session anchor point being deployed in a first ground network.

9. The method of claim 8, wherein, The sending of the second split rule comprises: sending the second split rule when the path state information indicates that the path state between the first network element and the second network element is an unavailable state.

10. The method of claim 8, wherein, The method further comprises: sending first indication information, the first indication information being used to indicate that the second network element uses the first split rule or the second split rule according to the path state information.

11. The method of claim 10, wherein, The first indication information is further comprised in a message carrying the first split rule and the second split rule.

12. The method according to any one of claims 8 to 11, characterized in that, The method further comprises: receiving first information, the first information being used to indicate that the path state between the first network element and the second network element changes, or being used to indicate that a transmission path between the first network element and the second network element is switched; The sending of the first split rule comprises: sending the first split rule according to the first information; The sending of the second split rule comprises: sending the second split rule according to the first information.

13. The method according to any one of claims 1 to 5, characterized in that, The method further comprises: receiving second information, the second information comprising service flow information between the second terminal device and a ground access gateway, the ground access gateway being deployed in a 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 offloading rule and a fourth offloading rule are sent, the third offloading rule being used to instruct the second network element to send a third data packet to the session anchor, the third data packet being a data packet sent by the second terminal device to the ground access gateway, and the fourth offloading rule being used to instruct the second network element to send a fourth data packet from the session anchor to the second terminal device, the fourth data packet being a data packet sent by the ground access gateway to the second terminal device.

14. The method of claim 13, wherein, The method further comprises: receiving third information, the third information being used to indicate that a path state between the first network element and the second network element changes; 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, sending a path available indication 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, sending a path unavailable indication in response to the third information.

15. The method of claim 5, wherein, The first request message further comprises an IP address of the second terminal device and an IP address of the ground access gateway, and the method further comprises: sending a third offloading rule, the third offloading rule being used to instruct the second network element to send a third data packet from a session anchor to the second terminal device, the third data packet being a data packet sent by the ground access gateway to the second terminal device, the ground access gateway being deployed in a second ground network, the session anchor being deployed in a first ground network, and the third data packet being transmitted between the ground access gateway and the second network element through the session anchor.

16. A method of communication, comprising: The method is applied to a first proxy call session control function network element, and the method comprises: obtaining identification information of a third network element, the third network element being deployed in a first non-ground network device; sending the identification information of the third network element, the identification information of the third network element being used to obtain a transmission path between a third terminal device and a fourth terminal device, and the third network element providing services for the third terminal device; receiving a third response message, the third response message being used to indicate the transmission path between the third terminal device and the fourth terminal device, and the third network element being a user plane function network element or an access gateway.

17. The method of claim 16, wherein, The third network element is a user plane function network element, and the method further comprises: sending a third request message, the third request message comprising identification information of the third terminal device; The obtaining of the identification information of the third network element comprises: receiving a fourth response message, the fourth response message being a response message of the third request message, and the fourth response message comprising the identification information of the third network element.

18. The method of claim 16 or 17, wherein, The third response message comprises indication information of a first path and / or indication information of a second path, the first path is a path between the third terminal device and a fourth terminal device through a third network element and a fourth network element, the second path is a path between the third terminal device and the fourth terminal device through a session anchor or a ground access gateway, the fourth network element serves the fourth terminal device, the session anchor is deployed in a first ground network, the ground access gateway is deployed in a second ground network, the session anchor comprises a session anchor serving the third terminal device and a session anchor serving the fourth terminal device, and the ground access gateway comprises a ground access gateway serving the third terminal device and a ground access gateway serving the fourth terminal device.

19. The method of claim 18, wherein, When the fourth network element is a user plane function network element, the indication information of the first path comprises tunnel information of the fourth network element and an IP address of the fourth terminal device. Or, when the fourth network element is an access gateway, the indication information of the first path comprises an IP address of the fourth network element. If the second path is a path between the third terminal device and the fourth terminal device through a ground access gateway, the indication information of the second path comprises an IP address of the ground access gateway. Or, if the second path is a path between the third terminal device and the fourth terminal device through a session anchor, the indication information of the second path comprises an IP address of the fourth terminal device.

20. The method of claim 18 or 19, wherein, The method further comprises: sending call signaling, the call signaling being used to indicate the first path and / or the second path, the call signaling comprising any one of an IP address of the fourth terminal device, an IP address of a ground access gateway, and an IP address of the third network element, the ground access gateway being a ground access gateway serving the third terminal device.

21. The method of any one of claims 16-20, wherein, The method further comprises: receiving third information, the third information being used to indicate that a path state of the first path or the second path changes; sending fourth information, the fourth information being used to indicate that the first path is switched to the second path or used to indicate that the second path is switched to the first path.

22. The method of claim 21, wherein, When the fourth information is used to indicate that the first path is switched to the second path and the second path is a path between the third terminal device and the fourth terminal device through a ground access gateway, the fourth information comprises an IP address of the ground access gateway, the ground access gateway being a ground access gateway serving the third terminal device, and the ground access gateway being deployed in a second ground network; or, When the fourth information is used to indicate that the first path is switched to the second path and the second path is a path between the third terminal device and the fourth terminal device through a session anchor, the fourth information comprises an 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 comprises tunnel information of the third network element and an IP address of the third terminal device, and the third network element provides services for the third terminal device; Or, When the fourth information indicates switching the second path to the first path, and the third network element and the fourth network element are both access gateways, the fourth information comprises an IP address of the third network element.

23. The method of claim 21, wherein, The method further comprises: sending second indication information, the second indication information comprising address information required by the third terminal device for sending session data to the fourth terminal device through a target path, the target path being the first path or the second path.

24. The method of any one of claims 18-20, wherein, The method further comprises: sending fifth information, the fifth information comprising service flow information between the third terminal device and the ground access gateway.

25. The method of claim 20, wherein, The call signaling further comprises third indication information, the third indication information being used to instruct the third terminal device to use the first path or the second path to transmit data according to a path state of the first path and / or the second path.

26. The method of claim 20, wherein, The call signaling further comprises path selection policy, the path selection policy comprising one or more of initial path indication, path priority, path delay threshold value, or path packet loss rate threshold value.

27. The method of claim 20, wherein, The call signaling further comprises fourth indication information, the fourth indication information being used to instruct the third terminal device to perform path monitoring to obtain the path state of the first path and / or the second path.

28. The method of claim 16 or 17, wherein, The third network element is an access gateway, the third response message comprises information of a third path and / or information of a fourth path, the information of the third path comprising an IP address of a fourth network element, the fourth network element being deployed in a second non-terrestrial network device, the fourth network element being an access gateway, the fourth network element serving a fourth terminal device, the information of the fourth path comprising an IP address of a ground access gateway, the ground access gateway being deployed in a second ground network, the ground access gateway being an access gateway serving the fourth terminal device, the third path being a path between the third terminal device and the fourth terminal device through the third network element and the fourth network element, and the fourth path being a path between the fourth terminal device and the fourth terminal device through the third network element and the ground access gateway.

29. The method of claim 28, wherein, The method further comprises: sending fifth indication information, the fifth indication information being used to instruct the third network element to use the third path or the fourth path to transmit data according to a path state of the third path and / or the fourth path.

30. The method of claim 28 or 29, wherein, The method further comprises: sending path selection policy, the path selection policy comprising one or more of initial path indication, path priority, path delay threshold value, or path packet loss rate threshold value; sending sixth indication information, the sixth indication information being used to instruct the third network element to monitor the path state of the third path and / or the fourth path.

31. The method of claim 30, wherein, The method further comprises: determine the transmission path based on the path state information, the path state information being determined based on the identification information of the third network element, the path state information being used to indicate a path state between the third network element and the fourth network element.

32. A method of communication, comprising: The method is applied to a second proxy call session control function network element, and the method comprises: receiving identification information of a third network element, the identification information of the third network element being used to acquire a transmission path between the third terminal device and a fourth terminal device, the third network element providing service for the third terminal device, the third network element being a user plane function network element or an access gateway, and the third network element being deployed on a first non-terrestrial network device; sending a third response message, the third response message being used to indicate the transmission path between the third terminal device and the fourth terminal device.

33. The method of claim 32, wherein, The method further comprises: sending a second request message, the second request message comprising the identification information of the third network element; receiving a fourth response message, the fourth response message being a response message of the second request message, the fourth response message being used to indicate a path establishment state between the third network element and a fourth network element, the fourth network element providing service for the fourth terminal device, and the fourth network element being deployed on a second non-terrestrial network device; determining the transmission path between the third terminal device and the fourth terminal device according to the path establishment state between the third network element and the fourth network element.

34. The method of claim 33, wherein, if the path establishment state between the third network element and the fourth network element is a successful establishment state, the fourth response message comprising indication information of a first path; or, if the path establishment state between the third network element and the fourth network element is a failed establishment state, the fourth response message comprising indication information of a second path.

35. The method of claim 34, wherein, when the third network element is a user plane function network element, the indication information of the first path comprising tunnel information of the third network element and an IP address of the fourth terminal device, and the indication information of the second path comprising an IP address of the ground access gateway; or when the third network element is an access gateway, the indication information of the first path comprising an IP address of the third network element, and the indication information of the second path comprising an IP address of the ground access gateway.

36. The method of claim 34 or 35, wherein, The method further comprises: receiving third information, the third information being used to indicate that a path state of the first path or the second path has changed; sending fourth information, the fourth information being used to indicate that the first path is switched to the second path, or being used to indicate that the second path is switched to the first path.

37. The method of claim 36, wherein, when the fourth information is used to indicate that the first path is switched to the second path, the fourth information comprising an IP address of a ground access gateway, the ground access gateway being deployed on a second ground network; or when the fourth information is used to indicate that the second path is switched to the first path, and the third network element and the fourth network element are both user plane function network elements, the fourth information comprising tunnel information of the third network element and an 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 and the fourth network element are both access gateways, the fourth information comprises an IP address of the fourth network element.

38. The method of claim 37, wherein, The method further comprises: sending second indication information, the second indication information being 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 of claim 37, wherein, The method further comprises: sending fifth information, the fifth information comprising traffic flow information between the fourth terminal device and the ground access gateway.

40. The method of any one of claims 34-39, wherein, The method further comprises: receiving call signaling, the call signaling being used to indicate the first path and / or the second path, the call signaling comprising any one of the following: an IP address of the fourth terminal device, an IP address of a ground access gateway, an IP address of the third network element, the ground access gateway being a ground access gateway serving the third terminal device.

41. The method of claim 40, wherein, The call signaling further comprises third indication information, the third indication information being used to instruct the fourth terminal device to use the first path or the second path to transmit data according to a path state of the first path and / or the second path.

42. The method of claim 40 or 41, wherein, The call signaling further comprises path selection policy, the path selection policy comprising one or more of the following: initial path indication, path priority, selecting a path with low latency, selecting a path with low packet loss rate, path latency threshold, and path packet loss rate threshold.

43. The method of any one of claims 40-42, wherein, The call signaling further comprises fourth indication information, the fourth indication information being used to instruct the fourth terminal device to perform path monitoring to obtain the path state of the first path and / or the second path.

44. The method of any one of claims 32-43, wherein, The third network element is an access gateway, the third response message comprises information of a third path and / or information of a fourth path, the information of the third path comprises an IP address of the third network element, the information of the fourth path comprises an IP address of a ground access gateway, the ground access gateway is deployed in a second ground network, the third path is a path between the third network element and the fourth network element, and the fourth path is a path between the fourth network element and the ground access gateway.

45. The method of claim 44, wherein, The method further comprises: sending fifth indication information, the fifth indication information being used to instruct the fourth network element to use the third path or the fourth path to transmit data according to a path state of the third path and / or the fourth path.

46. The method of claim 44 or 45, wherein, The method further comprises: sending path selection policy, the path selection policy comprising one or more of the following: initial path indication, path priority, selecting a path with low latency, selecting a path with low packet loss rate, path latency threshold, and path packet loss rate threshold. sending sixth indication information, the sixth indication information being used to instruct the fourth network element to monitor the path state of the third path and / or the fourth path.

47. The method of any one of claims 32-46, wherein, When the third network element and the fourth network element are both access gateways, the third response message comprises path state information, and the method further comprises: determine a transmission path based on path status information, the path status information being determined based on the identification information of the third network element, the path status information being used to indicate a path status between the third network element and the fourth network element, the fourth network element providing service for the fourth terminal device.

48. A method of communication, the method comprising: The method is applied to a fourth network element, and the method comprises: determining path status information, the path status information being used to indicate a path status between a third network element and the fourth network element, the third network element being deployed in a first non-ground network device, the fourth network element being deployed in a second non-ground network device, the third network element and the fourth network element both being user plane function network elements, or the third network element and the fourth network element both being access gateways; sending the path status information, the path status information being used to determine a transmission path between a third terminal device and a fourth terminal device, the third network element providing service for the third terminal device, and the fourth network element providing service for the fourth terminal device.

49. The method of claim 48, wherein, The transmission path comprises a first path and / or a second path, the first path being a 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 being a path between the third terminal device and the fourth terminal device through a session anchor or a ground access gateway, the session anchor being deployed in a first ground network, or the ground access gateway being deployed in a second ground network.

50. The method of claim 49, wherein, The fourth network element is a user plane function network element, and the method further comprises: when the second path is a path between the third terminal device and the fourth terminal device through a session anchor, receiving a first offloading rule and / or a second offloading rule, the first offloading rule being used to indicate the first path, and the second offloading rule being used to indicate the second path.

51. The method of claim 50, wherein, The method further comprises: receiving first indication information, the first indication information being used to indicate that the first offloading rule or the second offloading rule is used according to path status information; in response to the first indication information, determining a transmission path of a first data packet according to the path status information and using the first offloading rule or the second offloading rule.

52. The method of claim 51, wherein, The method further comprises: if a path status of the first path is an available state, determining that the transmission path is the first path; or if the path status of the first path is an unavailable state, determining that the transmission path is the second path.

53. The method of claim 48, wherein, The third network element and the fourth network element are access gateways, and the transmission path comprises a third path and / or a fourth path, the third path being a path between the third network element and the fourth network element, and the fourth path being a path between the third network element and the fourth network element through a ground access gateway, the ground access gateway being deployed in a second ground network.

54. The method of claim 53, wherein, The method further comprises: receiving fifth indication information, the fifth indication information being used to indicate that the fourth network element uses the third path or the fourth path to transmit data according to a path status of the third path and / or the fourth path.

55. The method of claim 53 or 54, wherein, The method further comprises: The path selection strategy includes one or more of an initial path indication, a path priority, a path with a low latency, a path with a low packet loss rate, a path latency threshold, and a path packet loss rate threshold.

56. The method of any one of claims 53-55, wherein, The method further includes: receiving a path state subscription request, the path state subscription request being used to request sending of a path state notification message when a path state between the fourth network element and any of the at least one network element changes; sending the path state notification message, the path state notification message being used to indicate the path state between the fourth network element and any of the at least one network element, the path state notification message including path state information.

57. The method of any one of claims 48-56, wherein, The method further includes: receiving a query request message, the query request message including identification information of the third network element, the query request message being used to request querying a path state between the third network element and the fourth network element; sending a first response message, the first response message being a response message of the query request message, the first response message being used to indicate path state information.

58. A method of communication, comprising: The method is applied to a terminal device, and the method includes: receiving indication information of a first path and indication information of a second path, the first path being used to directly send a second data packet to a fourth terminal device, the second path being used to send the second data packet to the fourth terminal device through a ground access gateway, the second data packet being a data packet sent to the fourth terminal device; determining a transmission path of the second data packet according to the indication information of the first path and the indication information of the second path.

59. The method of claim 58, wherein, The indication information of the first path includes an IP address of the fourth terminal device, and the indication information of the second path includes an IP address of the ground access gateway, the ground access gateway providing services for a third terminal device.

60. The method of claim 58 or 59, wherein, The method further includes: receiving third indication information, the third indication information being used to indicate determining a path of a second data packet according to a state of the first path or the second path.

61. The method of any one of claims 58-60, wherein, The method further includes: receiving fourth indication information, the fourth indication information being used to indicate monitoring a state of the first path or the second path.

62. The method of any one of claims 58-61, wherein, The method further includes: receiving a path selection strategy, the path selection strategy including one or more of an initial path indication, a path priority, a path with a low latency, a path with a low packet loss rate, a path latency threshold, and a path packet loss rate threshold.

63. The method of any one of claims 58-62, wherein, The method further includes: monitoring a state of the first path and / or the second path.

64. A communications device, characterized by include a module or unit for performing the method of any of claims 1-15, or include a module or unit for performing the method of any of claims 16-31, or include a module or unit for performing the method of any of claims 32-47, or include a module or unit for performing the method of any of claims 48-57, or include a module or unit for performing the method of any of claims 58-63.

65. A communications device, characterized by include: a processor configured to execute a program causing the communication device to perform the method of any of claims 1 to 15, or, the method of any of claims 16 to 31, or, the method of any of claims 32 to 47, or, the method of any of claims 48 to 57, or, the method of any of claims 58 to 63.

66. A communication system, characterized by comprising: a terminal device, a first network element, a second network element, a communication device configured to perform the method of any of steps 1 to 15, and a communication device configured to perform the method of any of steps 16 to 31; or, a communication device configured to perform the method of any of steps 58 to 63, a first network element, a second network element, a communication device configured to perform the method of any of steps 32 to 47, a communication device configured to perform the method of any of steps 48 to 57, a communication device configured to perform the method of any of steps 1 to 15, and a communication device configured to perform the method of any of steps 16 to 31.

67. A computer-readable storage medium, comprising: instructions which, when run on a computer, cause the computer to perform the method of any of claims 1 to 15, or, cause the computer to perform the method of any of claims 16 to 31, or, cause the computer to perform the method of any of claims 32 to 47, or, cause the computer to perform the method of any of claims 48 to 57, or, cause the computer to perform the method of any of claims 58 to 63.

68. A computer program product comprising instructions, wherein: instructions which, when run on a computer, cause the computer to perform the method of any of claims 1 to 15, or, cause the computer to perform the method of any of claims 16 to 31, or, cause the computer to perform the method of any of claims 32 to 47, or, cause the computer to perform the method of any of claims 48 to 57, or, cause the computer to perform the method of any of claims 58 to 63.

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