Switching method and device, satellite, network function, storage medium and computer program product

Abstract

The invention discloses a switching method and device, a satellite, a network function, a storage medium and a computer program product, and the method comprises the steps: a first satellite provided with first network equipment and a first network function receives first information sent by second network equipment on a second satellite to the first network equipment, receiving second information sent by a second network function on the ground to the first network function through the gateway station; wherein the first information is sent before the second network equipment moves out of a communication range of a first terminal accessed to the second network equipment, and represents synchronous data of switching a communication service of the first terminal from the second satellite to the first satellite; the second information represents that the second network function selects the first network function as the target network function of the first terminal, and the source network function of the first terminal is a third network function on the second satellite.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a switching method, device, satellite, network function, storage medium and computer program product. Background Art

[0002] In the related art, for the scenario where the terminal or user equipment (UE) is directly connected to the satellite, a satellite networking architecture of a base station, a user plane function (UPF) UPF and an access gateway (AGW) is proposed. The AGW can also be replaced by a user plane session border controller (SBC-U, Session Border Controller-User Plane), such as Figure 1 However, during the movement of the satellite, the current call service of the UE may be interrupted, and other UEs within the coverage of the satellite may be unable to establish on-board communication connections. Summary of the invention

[0003] To solve related technical problems, embodiments of the present application provide a switching method, device, satellite, network function, storage medium and computer program product.

[0004] The technical solution of the embodiment of the present application is implemented as follows:

[0005] An embodiment of the present application provides a switching method, which is applied to a first satellite, where at least a first network device and a first network function are deployed on the first satellite, and the method includes:

[0006] receiving first information sent by a second network device on a second satellite to the first network device; the first information is sent before the second network device moves out of the communication range of the first terminal accessing the second network device, and represents synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite;

[0007] Receive second information sent by a second network function on the ground to the first network function through a gateway, where the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is a third network function on the second satellite.

[0008] The embodiment of the present application further provides a switching method, which is applied to a second satellite, where at least a second network device and a third network function are deployed on the second satellite, and the method includes:

[0009] Sending first information sent by the second network device to a first network device on a first satellite; wherein the first information is sent before the second network device moves out of the communication range of the first terminal accessing the second network device, and represents synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite; or

[0010] Receive fifth information sent by the fourth network function where the protocol data unit (PDU) session of the first terminal is located to the second network device through the gateway; wherein the fifth information is sent after the fourth network function establishes a connection with the first network device on the first satellite, indicating that the communication service of the first terminal can be switched from the second satellite to the first satellite.

[0011] The embodiment of the present application further provides a switching method, which is applied to a fourth network function on the ground, and the method includes:

[0012] When the fourth network function establishes a connection with the first network device on the first satellite, fifth information is sent to the second network device on the second satellite through the gateway, and the fifth information indicates that the communication service of the first terminal accessing the second network device can be switched from the second satellite to the first satellite.

[0013] The embodiment of the present application also provides a switching method, which is applied to a second network function on the ground, and the method includes:

[0014] receiving a sixth request or a seventh request sent by a fourth network function on the ground; wherein the sixth request and the seventh request are used to request to update the context of the PDU session of the first terminal, and carry at least an identifier of the PDU session of the first terminal, a switching type representing the inter-satellite switching, and an identifier of the first satellite, and the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite;

[0015] Second information is sent to the first network function on the first satellite through the gateway, where the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

[0016] The embodiment of the present application further provides a switching method, which is applied to the eighth network function on the ground, and the method includes:

[0017] receiving seventh information sent by a second network function on the ground, where the seventh information indicates that a PDU session connection of a first terminal is switched from a third network function on the second satellite to a first network function on the first satellite, and the first terminal represents a terminal requesting to switch a communication service from the second satellite to the first satellite;

[0018] The seventh information is sent to a sixth network function on the ground, where the sixth network function represents a network function to which the multimedia session of the first terminal accesses.

[0019] The embodiment of the present application further provides a switching method, which is applied to the sixth network function on the ground, and the method includes:

[0020] receiving seventh information sent by an eighth network function on the ground, where the seventh information indicates that a PDU session connection of the first terminal is switched from a third network function on the second satellite to a first network function on the first satellite, where the first terminal represents a terminal requesting to switch a communication service from the second satellite to the first satellite, and where the sixth network function represents a network function accessed by a multimedia session of the first terminal;

[0021] Fourth information is sent to a fifth network function related to the multimedia session on the first satellite through the gateway, where the fourth information indicates allocation of media resources for the first terminal.

[0022] The present application also provides a communication device, including:

[0023] A first receiving unit is configured to receive first information sent by a second network device on a second satellite to a first network device on a first satellite; the first information is sent before the second network device moves out of a communication range of a first terminal accessing the second network device, and represents synchronization data for switching a communication service of the first terminal from the second satellite to the first satellite;

[0024] A second receiving unit is used to receive second information sent by a second network function on the ground to the first network function on the first satellite through a gateway, wherein the second information represents that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

[0025] The present application also provides a communication device, including:

[0026] a transceiver unit, configured to send first information sent by a second network device on a second satellite to a first network device on a first satellite, or to receive fifth information sent by a fourth network function where a PDU session of the first terminal is located to the second network device through a gateway; wherein,

[0027] The first information is sent before the second network device on the second satellite moves out of the communication range of the first terminal accessing the second network device, and represents synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite;

[0028] The fifth information is sent after the fourth network function establishes a connection with the first network device on the first satellite, indicating that the communication service of the first terminal can be switched from the second satellite to the first satellite.

[0029] The present application also provides a communication device, including:

[0030] The first sending unit is used to send fifth information to the second network device on the second satellite through the gateway when the fourth network function on the ground establishes a connection with the first network device on the first satellite, wherein the fifth information indicates that the communication service of the first terminal accessing the second network device can be switched from the second satellite to the first satellite.

[0031] The present application also provides a communication device, including:

[0032] A third receiving unit is configured to receive a seventh request sent by a fourth network function on the ground; wherein the seventh request is used to request to update the context of the PDU session of the first terminal, carries N2 SM information, a switching type representing the inter-satellite switching, and an identifier of the first satellite, and the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite;

[0033] The second sending unit is used to send second information to the first network function on the first satellite through the gateway, wherein the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

[0034] The present application also provides a communication device, including:

[0035] a fourth receiving unit, configured to receive a sixth request or a seventh request sent by a fourth network function on the ground; wherein the sixth request and the seventh request are used to request to update the context of the PDU session of the first terminal, and carry at least an identifier of the PDU session of the first terminal, a switching type representing the inter-satellite switching, and an identifier of the first satellite, and the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite;

[0036] The third sending unit is used to send the seventh information to a sixth network function on the ground, where the sixth network function represents the network function accessed by the multimedia session of the first terminal.

[0037] The present application also provides a communication device, including:

[0038] a fifth receiving unit, configured to receive seventh information sent by an eighth network function on the ground, where the seventh information indicates that a PDU session connection of the first terminal is switched from a third network function on the second satellite to a first network function on the first satellite, where the first terminal represents a terminal requesting to switch a communication service from the second satellite to the first satellite, and where the sixth network function represents a network function accessed by a multimedia session of the first terminal;

[0039] The fourth sending unit is configured to send fourth information related to the multimedia session on the first satellite to a fifth network function through the gateway, where the fourth information indicates allocation of media resources for the first terminal.

[0040] The embodiment of the present application further provides a first satellite, on which at least a first network device and a first network function are deployed, and the first satellite includes: a first processor and a first communication interface; wherein,

[0041] The first communication interface is used to receive first information sent by a second network device on a second satellite to a first network device on a first satellite, and to receive second information sent by a second network function on the ground to a first network function on the first satellite through a gateway; wherein,

[0042] The first information is sent before the second network device moves out of the communication range of the first terminal accessing the second network device, indicating that the communication service of the first terminal is switched from the second satellite to the synchronization data of the first satellite; the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

[0043] The embodiment of the present application further provides a second satellite, on which at least a second network device and a third network function are deployed, and the second satellite includes: a second processor and a second communication interface; wherein,

[0044] The second communication interface is used to send first information sent by the second network device on the second satellite to the first network device on the first satellite, or to receive fifth information sent by the fourth network function where the PDU session of the first terminal is located to the second network device through the gateway;

[0045] Among them, the first information is sent before the second network device on the second satellite moves out of the communication range of the first terminal accessing the second network device, indicating that the communication service of the first terminal is switched from the second satellite to the synchronization data of the first satellite; the fifth information is sent after the fourth network function establishes a connection with the first network device on the first satellite, indicating that the communication service of the first terminal can be switched from the second satellite to the first satellite.

[0046] The embodiment of the present application further provides a fourth ground network function, including: a third processor and a third communication interface; wherein,

[0047] The third communication interface is used to send fifth information to the second network device on the second satellite through the gateway when the fourth network function establishes a connection with the first network device on the first satellite, and the fifth information indicates that the communication service of the first terminal accessing the second network device can be switched from the second satellite to the first satellite.

[0048] The embodiment of the present application also provides a second ground network function, including: a fourth processor and a fourth communication interface; wherein,

[0049] The fourth communication interface is used to receive the sixth request or the seventh request sent by the fourth network function on the ground, and to send the second information to the first network function on the first satellite through the gateway; wherein,

[0050] The sixth request and the seventh request are used to request updating the context of the PDU session of the first terminal, and carry at least the identifier of the PDU session of the first terminal, the switching type representing the inter-satellite switching, and the identifier of the first satellite. The first terminal represents the terminal requesting to switch the communication service from the second satellite to the first satellite; the second information represents that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

[0051] The embodiment of the present application further provides an eighth ground network function, including: a fifth processor and a fifth communication interface; wherein,

[0052] The fifth communication interface is used to receive the seventh information sent by the second network function on the ground, and to send the seventh information to the sixth network function on the ground; wherein,

[0053] The seventh information indicates that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, and the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite; the sixth network function represents the network function of the multimedia session access of the first terminal.

[0054] The embodiment of the present application further provides a sixth ground network function, including a sixth processor and a sixth communication interface; wherein,

[0055] The sixth communication interface is used to receive seventh information sent by an eighth network function on the ground, and to send fourth information related to a fifth network function of the multimedia session on the first satellite through the gateway;

[0056] The seventh information indicates that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite, the sixth network function represents a network function for multimedia session access of the first terminal; and the fourth information indicates allocation of media resources for the first terminal.

[0057] An embodiment of the present application also provides a first satellite, comprising a first processor and a first memory for storing a computer program that can be run on the first processor, wherein the first processor is used to execute the steps of any one of the above-mentioned methods on the first satellite side when running the computer program.

[0058] An embodiment of the present application also provides a second satellite, comprising a second processor and a second memory for storing a computer program that can be run on the second processor, wherein the second processor is used to execute the steps of any of the above-mentioned methods on the second satellite side when running the computer program.

[0059] An embodiment of the present application also provides a fourth ground network function, including a third processor and a third memory for storing a computer program that can be run on the third processor, wherein the third processor is used to execute the steps of any method on the fourth ground network function side when running the computer program.

[0060] An embodiment of the present application also provides a ground-based second network function, including a fourth processor and a fourth memory for storing a computer program that can be run on the fourth processor, wherein the fourth processor is used to execute the steps of any method on the ground-based second network function side when running the computer program.

[0061] An embodiment of the present application also provides an eighth ground network function, including a fifth processor and a fifth memory for storing a computer program that can be run on the fifth processor, wherein the fifth processor, when used to run the computer program, executes the steps of any method on the eighth ground network function side mentioned above.

[0062] An embodiment of the present application also provides a sixth ground network function, characterized in that it includes a sixth processor and a sixth memory for storing a computer program that can be run on the sixth processor, wherein the sixth processor is used to execute the steps of any method of the above-mentioned sixth ground network function when running the computer program.

[0063] An embodiment of the present application also provides a storage medium having a computer program stored thereon, characterized in that when the computer program is executed by a processor, the steps of any one of the above-mentioned methods of the first satellite, the second satellite, the fourth network function on the ground, the second network function on the ground, the eighth network function on the ground, or the sixth network function on the ground are implemented.

[0064] In the switching method, apparatus, satellite, network function, storage medium and computer program product provided in the embodiments of the present application, when a fourth network function on the ground establishes a connection with a first network device on a first satellite, the fourth network function sends fifth information to a second network device on a second satellite through a gateway, wherein the fifth information indicates that the communication service of a first terminal accessing the second network device can be switched from the second satellite to the first satellite, wherein at least the first network device and the first network function are deployed on the first satellite, and at least the second network device and the third network function are deployed on the second satellite; the second satellite receives the fifth information sent by the fourth network function where the PDU session of the first terminal is located to the second network device through the gateway, or the second satellite sends the first information sent by the second network device to the first network device, wherein the first information is sent before the second network device moves out of the communication range of the first terminal, indicating synchronization data of switching the communication service of the first terminal from the second satellite to the first satellite; the second network function on the ground receives the sixth request or the seventh request sent by the fourth network function, and sends the second information to the first network function on the first satellite through the gateway, wherein the sixth request and the seventh request are sent to the synchronization data of ... The requests are all used to request to update the context of the PDU session of the first terminal, and carry at least the identifier of the PDU session of the first terminal, the switching type representing the inter-satellite switching, and the identifier of the first satellite, the second information represents that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite; the first satellite receives the first information sent by the second network device on the second satellite to the first network device on the first satellite, and receives the second information sent by the second network function on the ground to the first network function on the first satellite through the gateway; the eighth network function on the ground receives the seventh information sent by the second network function, and sends the seventh information to the sixth network function on the ground, the seventh information indicates that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, and the sixth network function represents the network function accessed by the multimedia session of the first terminal; the sixth network function receives the seventh information sent by the eighth network function, and sends fourth information to the fifth network function related to the multimedia session on the first satellite through the gateway, and the fourth information indicates that media resources are allocated to the first terminal.It can be seen that in an embodiment of the present application, when the Xn extended interface is supported between the first satellite and the second satellite, the first satellite receives the first information sent by the second network device on the second satellite to the first network device on the first satellite, and receives the second information sent by the second network function on the ground to the first network function through the gateway; when the Xn extended interface is not supported between the first satellite and the second satellite, after the fourth network function where the PDU session of the first terminal is located establishes a connection with the first network device on the first satellite, the fifth information is sent to the second network device on the second satellite through the gateway to indicate that the communication service of the first terminal can be switched from the second satellite to the first satellite; since the first information represents the synchronization data of the communication service of the first terminal being switched from the second satellite to the first satellite, and the second information represents that the second network function on the ground selects the first network function on the first satellite as the destination network function of the first terminal, the second network function on the ground can request the fourth network function on the ground to update the first terminal The context of the PDU session of the first terminal is obtained by the ground-based second network function. Therefore, after the first terminal switches to the first network device on the first satellite, the continuity of the communication service of the first terminal can be guaranteed; and the second network function on the ground indicates to the sixth network function on the ground through the eighth network function on the ground that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, so that the third network function on the second satellite can release the resources occupied by the PDU session of the first terminal, thereby reducing the waste of network resources; the sixth network function on the ground indicates to the fifth network function related to the multimedia session on the first satellite through the gateway station to allocate media resources for the first terminal, so as to switch the multimedia session of the first terminal from the second satellite to the fifth network function related to the multimedia session on the first satellite, thereby ensuring the continuity of the multimedia session of the first terminal, and also enabling the network function related to the multimedia session on the first satellite to release the resources occupied by the multimedia session of the first terminal, thereby reducing the waste of network resources. In the above scheme, through the coordination of the onboard core network and the ground core network during inter-satellite switching, when the first terminal switches from the second network device on the second satellite to the first network device on the first satellite, the PDU session of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, and the multimedia session of the first terminal is switched from the second satellite to the fifth network function on the first satellite, which can ensure the continuity of the communication service of the first terminal and reduce the waste of resources of the second satellite. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a sample diagram of the satellite-ground networking system architecture for related technologies;

[0066] Figure 2This is an example diagram of the PDU and IMS call establishment process in a scenario where a terminal is directly connected to a satellite and a base station, UPF and AGW (SBC-U) are deployed on the satellite, to which the embodiments of the related technology of the present application are applicable;

[0067] Figure 3 The following is an example diagram of the handover solution flow of the terminal moving between base stations supporting the Xn interface after the PDU session is established in the related technology;

[0068] Figure 4 This is an example diagram of the handover process of a terminal moving between base stations that do not support the Xn interface after a PDU session is established in the related technology;

[0069] Figure 5 Example diagram of the communication system architecture of the base station, UPF and AGW (or SBC-U) on-satellite networking applicable to the embodiments of the present application;

[0070] Figure 6 A schematic diagram of an interactive process of a switching method according to an embodiment of the present application;

[0071] Figure 7 A schematic diagram of an interactive process of a switching method according to an embodiment of the present application;

[0072] Figure 8 A schematic diagram of a switching method implementation flow in an embodiment of the present application;

[0073] Fig. 9 A schematic diagram of a switching method implementation flow in an embodiment of the present application;

[0074] Fig.10 A schematic diagram of a switching method implementation flow in an embodiment of the present application;

[0075] Fig.11 A schematic diagram of a switching method implementation flow in an embodiment of the present application;

[0076] Fig.12 A schematic diagram of a switching method implementation flow in an embodiment of the present application;

[0077] Fig.13 A schematic diagram of a switching method implementation flow in an embodiment of the present application;

[0078] Fig.14 This is a schematic diagram of the structure of a switching device according to an embodiment of the present application;

[0079] Fig.15 This is a schematic diagram of the structure of a switching device according to an embodiment of the present application;

[0080] Fig.16 This is a schematic diagram of the structure of a switching device according to an embodiment of the present application;

[0081] Fig.17 This is a schematic diagram of the structure of a switching device according to an embodiment of the present application;

[0082] Fig.18 This is a schematic diagram of the structure of a switching device according to an embodiment of the present application;

[0083] Fig.19 This is a schematic diagram of the structure of a switching device according to an embodiment of the present application;

[0084] Fig. 20 This is a schematic diagram of the structure of the first satellite in an embodiment of the present application;

[0085] Fig.21 This is a schematic diagram of the structure of the second satellite in an embodiment of the present application;

[0086] Fig. 22 This is a schematic diagram of the fourth network function structure of the ground embodiment of the present application;

[0087] Fig.23 This is a schematic diagram of the functional structure of the second network on the ground in an embodiment of the present application;

[0088] Fig.24 This is a schematic diagram of the eighth network function structure of the ground embodiment of the present application;

[0089] Fig.25 This is a schematic diagram of the sixth network functional structure of the ground embodiment of the present application. DETAILED DESCRIPTION

[0090] For the scenario where the terminal or user equipment (UE) is directly connected to the satellite, a satellite networking architecture with base station, user plane function (UPF) and access gateway (AGW) is proposed. AGW can also be the session border controller (SBC-U) of the user plane, such as Figure 1 shown. Figure 1In the ground gateway, the ground network can communicate with the access and mobility management function (AMF), session management function (SMF), and call session control function (CSCF) in the ground network. SMF can connect to the application server (AS) through the policy control function (PCF) and CSCF. Among them, CSCF can include the proxy call session control function (P-CSCF), the interrogating-CallSession Control Function (I-CSCF) and the serving CSCF (S-CSCF) according to its function. The interrogating-CSCF is the entry point of the IP Multimedia Subsystem (IMS) home network. I-CSCF and S-CSCF can be abbreviated as I / S-CSCF. When the AGW is SBC-U, the P-CSCF can be replaced by the SBC control plane (SBC-C, Session Border Controller-Control Panel).

[0091] Figure 2 This article provides an example of the protocol data unit (PDU) and IMS call establishment process in the scenario where the terminal is directly connected to the satellite, the base station, UPF and AGW (or SBC-U) are on the satellite. The specific process is as follows:

[0092] 1. After UE-1 (calling UE) completes the registration of the core network (CN) through the satellite base station, it sends a PDU session establishment request to the satellite base station.

[0093] 2. After receiving the PDU session establishment request, the satellite base station sends the PDU session establishment request to the ground AMF through the ground gateway.

[0094] 3. After receiving the PDU session establishment request, the ground AMF selects the ground SMF and sends a request to create a session context.

[0095] 4. The ground SMF obtains the user contract data from the Unified Data Management (UDM), allows the PDU session to be established, and sends a create session context response to the ground AMF.

[0096] 5. The ground SMF establishes an SM policy association with the ground PCF. The SMF selects the onboard UPF based on the satellite access information and the data network name (DNN). The SM policy refers to the control policy provided by the PCF to the SMF for PDU session management.

[0097] 6. The ground SMF sends an N4 session establishment request to the onboard UPF through the ground gateway.

[0098] 7. After receiving the N4 session establishment request, the onboard UPF returns the N4 session establishment response to the ground SMF through the ground gateway.

[0099] 8. The ground SMF sends an N1N2 message transmission request to the AMF, such as Namf_Communication_N1N2MessageTransfer. The N1N2 message transmission request carries the satellite CN tunnel information and P-CSCF (or SBC-C) address, etc.

[0100] 9. AMF sends an N1N2 message transmission request to the satellite base station and UE-1 through the ground gateway, and the network interacts with UE-1 to complete the establishment of the PDU session.

[0101] 10. UE-1 uses the obtained P-CSCF (or SBC-C) address to send a registration request to the satellite base station and satellite UPF.

[0102] 11. The onboard UPF forwards the registration request to the ground P-CSCF (or SBC-C) through the ground gateway based on the destination address, etc.

[0103] 12. The P-CSCF sends a registration request to the I / S-CSCF based on the domain name address information in the registration request.

[0104] 13. The I / S-CSCF interacts with UE-1 through the P-CSCF (or SBC-C), satellite UPF, and satellite base station to complete IMS authentication and sends a 200 response to the P-CSCF (or SBC-C).

[0105] 14. P-CSCF (or SBC-C) sends a 200 response to UE-1 through the ground gateway, satellite UPF, and satellite base station to complete the IMS registration.

[0106] 15. UE-1 sends an invite request to the ground P-CSCF (or SBC-C) through the satellite base station, satellite UPF, and ground gateway.

[0107] 16. After receiving the Invite request, the P-CSCF (or SBC-C) interacts with the onboard AGW (or SBC-U) through the ground gateway to complete the media resource allocation, and modifies the media address to the address of the onboard AGW (or SBC-U) in the Session Description Protocol (SDP) of the Invite request sent to the I / S-CSCF.

[0108] 17. The I / S-CSCF forwards the Invite request to the called network and UE-2 (called UE) for media negotiation.

[0109] 18. UE-2 responds and sends a 200 response to UE-1 through the called network, the calling terrestrial network, and the satellite network, completing the call establishment.

[0110] In the scenario where the movement of UE in the ground network causes base station switching, the relevant technology has developed a switching solution process between base stations that supports the Xn interface and a switching solution process between base stations that do not support the Xn interface and use the N2 interface.

[0111] In the scenario of a handover solution between base stations supporting the Xn interface, after the PDU session is established, the handover solution process of the UE moving between base stations supporting the Xn interface is as follows: Figure 3 The specific process is as follows:

[0112] 1. UE-1 establishes a PDU session through the source base station, AMF, SMF and UPF.

[0113] 2. UE-1 establishes a satellite-to-ground IMS call with the peer UE-2 through SBC-U, CSCF, etc.

[0114] 3. Before UE-1 moves out of the coverage of the source base station, the source base station synchronizes the PDU session, AMF identification address, UE identification and other related session switching data to the destination base station.

[0115] 4. The source base station determines to initiate a handover based on the measurement report (MR), and sends a radio resource control (RRC) reconfiguration request to UE-1, carrying the handover target cell information.

[0116] 5. After receiving the message, UE-1 synchronizes to the target cell and completes the handover, and sends an RRC Reconfiguration Complete message to the target base station.

[0117] 6. After receiving the RRC reconfiguration completion message, the destination base station sends an N2 path switching request to the AMF where the PDU session is located, carrying N2 SM information (including the switched PDU session information, AN tunnel information, UE location information, etc.), etc. SM refers to session management (Session Management), and AN refers to access network (Access Network).

[0118] 7. AMF sends a session context update request to SMF based on the session information in the received request, carrying N2 SM information, etc.

[0119] 8. After receiving the update session context request, the SMF obtains the N2 SM information from the update session context request and sends an N4 session modification request to the UPF with the established session, carrying the AN tunnel information.

[0120] 9. UPF (onboard UPF) returns a session modification response to SMF, carrying CN tunnel information.

[0121] 10. After receiving the response, SMF sends an update session context response to AMF, carrying N2 SM information (including the switched PDU session QoS information, CN tunnel information, etc.).

[0122] 11. After receiving the message, AMF sends N2 path switching confirmation to the destination base station, carrying N2 SM information.

[0123] 12. After receiving the N2 path switching confirmation, the destination base station confirms that the switching is complete, establishes the N3 tunnel with the UPF, and sends a release resource message to the source base station to release the session resources of the source base station.

[0124] In the scenario where the base station does not support the Xn interface and uses the N2 interface for handover, after the PDU session is established, the handover process of the UE moving between base stations that do not support the Xn interface is as follows: Figure 4 The specific process is as follows:

[0125] 1. UE-1 (calling UE) establishes a PDU session through the source base station, AMF, SMF and UPF.

[0126] 2. UE-1 establishes a satellite-to-ground IMS call with the peer UE-2 (called UE) through network functions such as SBC-U and CSCF.

[0127] 3. The source base station sends a handover request to the AMF, carrying information such as the synchronization data from the source base station to the target base station, the ID of the target base station to be handed over, and the PDU session identifier.

[0128] 4. After receiving the switching request, AMF sends a request to update the PDU session context to SMF, carrying information such as the switching destination base station ID and PDU session identifier.

[0129] 5. After receiving the request to update the PDU session context, SMF combines the target base station for switching and the switching PDU session, determines that the switching is allowed, and returns an update PDU session context response to AMF. The response carries information such as the switching PDU session identifier, CN tunnel, and UPF address.

[0130] 6. After receiving the response to update the PDU session context, the AMF sends a handover request to the destination base station, carrying information such as source to destination transparent container data, CN tunnel and UPF N3 address.

[0131] 7. After receiving the handover request, the destination base station sends a handover request confirmation to the AMF, carrying information such as the destination to source transparent container data, AN tunnel and radio access network (RAN, Radio Access Network) N3 address.

[0132] 8. After receiving the handover request confirmation, AMF sends an update PDU session context request to SMF, which carries the handover confirmation indication, AN tunnel and RAN N3 address and other information.

[0133] 9. After receiving the request to update the PDU session context, SMF sends an N4 session modification request to UPF based on information such as the switching confirmation indication, carrying information such as the AN tunnel and RAN N3 address.

[0134] 10. After receiving the N4 session modification request, UPF (satellite UPF) establishes an N3 tunnel with the destination base station and returns an N4 session modification response to SMF.

[0135] 11. SMF sends an update PDU session context response to AMF.

[0136] 12. AMF sends a handover command to the source base station, carrying the transparent container data from the destination to the source and the handover session management information.

[0137] 13. After receiving the message, the source base station sends a handover command to UE-1.

[0138] 14. After receiving the handover command, UE-1 switches to the target cell according to the handover command instruction and sends a handover confirmation message to the target base station.

[0139] 15. After receiving the handover confirmation message, the destination base station sends a handover notification to the AMF, indicating that the handover is successful.

[0140] 16. After receiving the message, AMF sends a request to update the PDU session context to SMF, which carries information such as the switching completion indication.

[0141] 17. After receiving the message, SMF returns the updated PDU session context response to AMF to confirm that the handover is complete.

[0142] 18. The AMF protection timer times out and sends a UE context release message to the source base station.

[0143] 19. After the source base station completes the release, it returns the UE context release completion to the AMF.

[0144] In the scenario where the terminal is directly connected to a non-geostationary synchronous orbit (NGSO) satellite, and the base station, UPF, and AGW (or SBC-U) are on-board, the existing solution has the following problems:

[0145] 1. Impact on user experience: The existing solution does not consider the satellite networking of UPF and AGW (or SBC-U). When the NGSO satellite sends a switch due to movement, UPF and AGW (or SBC-U) will also switch accordingly. The existing solution only considers the base station switching and does not support the switching of UPF and AGW (or SBC-U), resulting in communication interruption. The user's current call service is interrupted without any prompt, and the user service experience is poor.

[0146] 2. Waste of network resources. The existing solution only considers base station switching and does not support the switching of UPF and AGW (or SBC-U). After the switching, the UPF and AGW (or SBC-U) communication resources on the source satellite cannot be released immediately, resulting in the occupation of limited network resources on the satellite. When other UEs under the satellite coverage access, the occupied resources lead to insufficient resources, making it impossible to establish some on-satellite communications.

[0147] Based on this, in various embodiments of the present application, when a fourth network function on the ground establishes a connection with a first network device on a first satellite, the fourth network function sends fifth information to a second network device on a second satellite through a gateway, wherein the fifth information indicates that the communication service of a first terminal accessing the second network device can be switched from the second satellite to the first satellite, and at least the first network device and the first network function are deployed on the first satellite, and at least the second network device and the third network function are deployed on the second satellite; the second satellite receives the fifth information sent by the fourth network function where the PDU session of the first terminal is located to the second network device through the gateway, or the second satellite sends the first information sent by the second network device to the first network device, and the first information is sent before the second network device moves out of the communication range of the first terminal, indicating synchronization data of switching the communication service of the first terminal from the second satellite to the first satellite; the second network function on the ground receives the sixth request or the seventh request sent by the fourth network function, and sends the second information to the first network function on the first satellite through the gateway, and both the sixth request and the seventh request are used to request to update the first a context of a PDU session of a terminal, carrying at least an identifier of the PDU session of the first terminal, a switching type representing an inter-satellite switching, and an identifier of a first satellite, wherein the second information represents that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is a third network function on the second satellite; the first satellite receives first information sent by a second network device on the second satellite to a first network device on the first satellite, and receives second information sent by a second network function on the ground to the first network function on the first satellite through a gateway; an eighth network function on the ground receives seventh information sent by the second network function, and sends the seventh information to a sixth network function on the ground, wherein the seventh information indicates that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, and the sixth network function represents a network function accessed by the multimedia session of the first terminal; the sixth network function receives the seventh information sent by the eighth network function, and sends fourth information to a fifth network function related to the multimedia session on the first satellite through a gateway, wherein the fourth information indicates that media resources are allocated to the first terminal.It can be seen that in an embodiment of the present application, when the Xn extended interface is supported between the first satellite and the second satellite, the first satellite receives the first information sent by the second network device on the second satellite to the first network device on the first satellite, and receives the second information sent by the second network function on the ground to the first network function through the gateway; when the Xn extended interface is not supported between the first satellite and the second satellite, after the fourth network function where the PDU session of the first terminal is located establishes a connection with the first network device on the first satellite, the fifth information is sent to the second network device on the second satellite through the gateway to indicate that the communication service of the first terminal can be switched from the second satellite to the first satellite; since the first information represents the synchronization data of the communication service of the first terminal being switched from the second satellite to the first satellite, and the second information represents that the second network function on the ground selects the first network function on the first satellite as the destination network function of the first terminal, the second network function on the ground can request the fourth network function on the ground to update the first terminal The context of the PDU session of the first terminal is obtained by the ground-based second network function. Therefore, after the first terminal switches to the first network device on the first satellite, the continuity of the communication service of the first terminal can be guaranteed; and the second network function on the ground indicates to the sixth network function on the ground through the eighth network function on the ground that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, so that the third network function on the second satellite can release the resources occupied by the PDU session of the first terminal, thereby reducing the waste of network resources; the sixth network function on the ground indicates to the fifth network function related to the multimedia session on the first satellite through the gateway station to allocate media resources for the first terminal, so as to switch the multimedia session of the first terminal from the second satellite to the fifth network function related to the multimedia session on the first satellite, thereby ensuring the continuity of the multimedia session of the first terminal, and also enabling the network function related to the multimedia session on the first satellite to release the resources occupied by the multimedia session of the first terminal, thereby reducing the waste of network resources. In the above scheme, through the coordination of the onboard core network and the ground core network during inter-satellite switching, when the first terminal switches from the second network device on the second satellite to the first network device on the first satellite, the PDU session of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, and the multimedia session of the first terminal is switched from the second satellite to the fifth network function on the first satellite, which can ensure the continuity of the communication service of the first terminal and reduce the waste of resources of the second satellite.

[0148] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0149] First, in order to better illustrate the switching method provided in the embodiment of the present application, Figure 5The present application embodiment is applicable to the base station, UPF and AGW (or SBC-U) on-satellite network communication system architecture example. Figure 5 In the system architecture shown: each satellite is deployed with at least a base station and a UPF, and may also be deployed with an AGW (or SBC-U). Any terminal can be directly connected to the satellite. The base station is also called a network device or an access network device, and the satellite includes an NGSO satellite. Figure 5 In the example, the first terminal (calling terminal) is directly connected to the source satellite, and an on-board PDU session is established through the base station and UPF on the source satellite, as well as the gateway station, the ground AMF and the ground SMF. When an AGW (or SBC-U) is also deployed on the source satellite, and an AGW (or SBC-U) is also deployed on the destination satellite, the first terminal establishes a satellite-to-ground multimedia session, such as an IMS call, with the second terminal (called terminal) through the UPF, AGW (or SBC-U) on the source satellite, and through the gateway station, the ground P-CSCF (or SBC-C), I / S-CSCF and other network functions. When SBC-U is used to replace the AGW on the satellite, SBC-C can be used to replace the ground P-CSCF. The gateway station can be called a ground gateway station.

[0150] When the first terminal switches from the base station on the source satellite to the base station on the destination satellite, the PDU session of the first terminal is switched from the UPF on the source satellite to the UPF on the destination satellite, and the multimedia session of the first terminal is switched from the AGW (or SBC-U) on the source satellite to the AGW (or SBC-U) on the destination satellite, so as to ensure the continuity of the communication service of the first terminal and to release the resources on the source satellite in time to reduce the waste of resources of the source satellite.

[0151] When the Xn extended interface is supported between the source satellite and the destination satellite, the first terminal is switched between satellites based on the Xn extended interface; when the Xn extended interface is not supported between the source satellite and the destination satellite, the first terminal is switched between satellites based on the N2 interface; the Xn extended interface can be described as an Xn+ interface, and the Xn+ interface exists on the inter-satellite link (ISL), that is, Xn+over ISL.

[0152] Combine the following Figure 6 and Figure 7 Two situations are introduced respectively: whether the source satellite and the destination satellite support or do not support the Xn extended interface. Figure 6 An example diagram of a switching method for performing inter-satellite switching on a first terminal based on the support of an Xn extended interface between a source satellite and a destination satellite is given. Figure 7 An example diagram of a handover method for performing inter-satellite handover on a first terminal based on an N2 interface is given. Figure 6 and Figure 7In this paper, a base station, UPF and AGW are deployed on a satellite as an example. Figure 6 and Figure 7 In the figure, the base station on the first satellite can be described as the first network device, the UPF on the first satellite can be described as the first network function, and the AGW on the first satellite can be described as the fifth network function; the base station on the second satellite can be described as the second network device, the UPF on the second satellite can be described as the third network function, and the AGW on the second satellite can be described as the seventh network function; the ground AMF can be described as the fourth network function on the ground, the ground SMF can be described as the second network function on the ground, the ground PCF can be described as the eighth network function, the P-CSCF of the first terminal can be described as the sixth network function on the ground, and the P-CSCF of the second terminal can be described as the ninth network function on the ground.

[0153] like Figure 6 As shown, in a scenario where the source satellite and the destination satellite support an Xn extended interface, a switching method for performing inter-satellite switching on a first terminal based on the Xn extended interface includes the following steps:

[0154] Step 1: The first satellite establishes an Xn extended interface connection with the second satellite via an inter-satellite link.

[0155] Here, base stations, UPFs and AWGs are deployed on both the first satellite and the second satellite. The first satellite and the second satellite include NGSOs.

[0156] Step 2: The first terminal directly connects to the second satellite, and establishes an on-satellite PDU session through the second on-satellite base station and UPF, as well as through the ground gateway, ground AMF and SMF.

[0157] Here, the second satellite is the source satellite of the first terminal, the base station on the second satellite is the source base station of the first terminal, and the UPF on the second satellite is the source UPF of the terminal. The first terminal is a calling terminal.

[0158] Step 3: The first terminal directly connects to the second satellite, and establishes a satellite-to-ground multimedia session, such as an IMS call or IMS session, with the second terminal through the base station, UPF and AGW on the second satellite, as well as through the ground gateway, ground P-CSCF, I / S-CSCF and other network functions.

[0159] Here, the AGW on the second satellite is the source AGW of the first terminal, and the second terminal is the called terminal. The P-CSCF of the first terminal (the connected P-CSCF of the first terminal) and the P-CSCF of the second terminal (the connected P-CSCF of the second terminal) may be different.

[0160] Step 4: The first satellite moves into the communication range of the gateway, and the base station on the second satellite establishes a connection with the ground AMF through the gateway, for example, establishing a Next Generation Application Protocol (NGAP) connection.

[0161] Here, the terrestrial AMF refers to the terrestrial AMF where the PDU session of the first terminal is located.

[0162] Step 5: The base station on the first satellite sends a first indication to the base station on the second satellite, where the first indication is used to indicate that the base station on the first satellite has established a connection with the ground AMF where the PDU session of the first terminal is located.

[0163] Here, the base station on the first satellite may send a connection establishment notification message to the base station on the second satellite, where the connection establishment notification message carries the first indication.

[0164] Step 6: The base station on the second satellite determines the switching preparation timing based on the satellite ephemeris data, the location information of the first terminal and the location information of the gateway; before the base station on the second satellite moves out of the communication range of the first terminal or before the switching preparation timing is reached, the base station on the second satellite selects the first satellite as the destination satellite of the first terminal, selects the first satellite as the switching destination satellite, and sends the first information to the base station on the first satellite through the inter-satellite link between the second satellite and the first satellite.

[0165] Here, the first information represents the synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite, and the first information includes the information of the PDU session of the first terminal, and the identifier and / or address of the ground AMF where the PDU session of the first terminal is located. The switching preparation timing is earlier than the time when the second satellite moves out of the communication range of the first terminal, that is, the switching preparation timing is before the time when the second satellite moves out of the communication range of the first terminal. Specifically, the switching preparation timing can be understood as the time when the first satellite enters or is about to enter the communication range of the first terminal, and the second satellite is still located in the communication range of the first terminal.

[0166] Step 7: The base station on the second satellite initiates a handover based on the measurement report and the satellite ephemeris data, and sends an RRC Reconfiguration message to the first terminal, carrying information of the target cell.

[0167] Here, the base station measurement report and satellite ephemeris data on the second satellite determine whether to initiate a handover; for example, a handover is initiated when the handover conditions are met and the handover preparation timing is reached. The target cell can be any cell on the first satellite.

[0168] Step 8: After receiving the RRC reconfiguration message, the first terminal switches to the target cell and sends an RRC Reconfiguration Complete message to the base station on the first satellite.

[0169] Step 9: The base station on the first satellite sends a first request to the ground AMF (the ground AMF where the PDU session of the first terminal is located) through the gateway.

[0170] Here, the first request is used to request switching of the N2 path. The first request can be understood as an N2 path switching request. The first request carries a switching type representing inter-satellite switching, an identifier of the first satellite, and N2 SM information; the N2 SM information includes at least information about the PDU session of the first terminal, N3 tunnel information, and location information of the first terminal. The switching type representing inter-satellite switching can be described as a SAT-SAT switching type.

[0171] Step 10: The ground AMF sends the seventh request to the ground SMF based on the PDU session information carried in the received first request.

[0172] Here, the seventh request is used to request to update the context of the PDU session of the first terminal. The seventh request can be understood as a request to update the session context, carrying N2 SM information, a switching type representing the inter-satellite switching, and an identifier of the first satellite.

[0173] Step 11: The ground SMF receives the seventh request, obtains N2 SM information, the switching type representing the inter-satellite switching, and the identifier of the first satellite from the seventh request; the ground SMF queries and selects the UPF on the first satellite as the destination UPF according to the identifier of the first satellite, and sends second information to the UPF on the first satellite through the gateway, and the second information represents that the ground SMF selects the UPF on the first satellite as the destination UPF for the first terminal.

[0174] Step 12: The ground SMF sends a second request to the UPF on the first satellite through the gateway. The second request is used to request to establish an N4 session of the first terminal and carries AN tunnel information.

[0175] Here, the second case can be understood as an N4 session establishment request.

[0176] Step 13: The UPF on the first satellite returns a response to the second request to the ground SMF through the gateway.

[0177] Here, the response to the second request can be understood as an N4 session establishment response, carrying CN tunnel information.

[0178] Step 14: The ground SMF receives a response to the second request and sends the seventh information to the ground PCF, where the seventh information indicates that the PDU session connection of the first terminal is switched from the UPF on the second satellite to the UPF on the first satellite.

[0179] Here, the first information can be understood as a connection change notification message. The seventh information includes one or more of the following: a connection change type characterizing an intersatellite connection change, an identifier of the first satellite, an address of the UPF on the first satellite, and a first state, wherein the first state characterizes an uncompleted change of the PDU session connection of the first terminal. The first device can be described as a connection change situation (in progress).

[0180] Since the ground SMF has saved the information of the first terminal and the information of the second satellite during the process of establishing the PDU session of the first terminal, the first information does not need to include the information of the first terminal and the information of the second satellite.

[0181] Step 15: The ground PCF receives the seventh information, saves at least the address of the UPF on the first satellite, determines the P-CSCF of the first terminal based on the association between the network functions established when the multimedia session is established, and sends the seventh information to the P-CSCF of the first terminal.

[0182] Step 16: The P-CSCF of the first terminal receives the seventh information, selects the AGW on the first satellite as the target AGW according to the identifier of the first satellite, and sends the fourth information to the AGW on the first satellite through the gateway, where the fourth information indicates that media resources are allocated to the first terminal.

[0183] Here, the fourth information indicates that the AGW on the first satellite allocates media resources for the multimedia session of the first terminal. When the AGW on the first satellite allocates media resources for the multimedia session of the first terminal, a message indicating that the media resource allocation is completed may be fed back to the P-CSCF of the first terminal.

[0184] Step 17: The P-CSCF of the first terminal sends the eighth information to the ground PCF, where the eighth information indicates confirmation that the PDU session connection of the first terminal can be switched from the UPF on the second satellite to the UPF on the first satellite.

[0185] Here, after the P-CSCF of the first terminal sends the fourth information, or receives a message indicating that the media resource allocation is completed from the AGW on the first satellite, it sends the eighth information to the ground PCF. The eighth information can be understood as a confirmation message of the connection change notification message.

[0186] Step 18: The ground PCF receives the eighth information and sends the eighth information to the ground SMF.

[0187] Step 19: The ground SMF receives the eighth information and sends an eighth request to the UPF on the second satellite through the gateway. The eighth request is used to request to end the N4 session of the first terminal.

[0188] Here, the eighth request can be understood as an N4 session end request.

[0189] Step 20: The UPF on the second satellite receives the eighth request and sends a first response to the ground SMF through the gateway. The first response is a response to the eighth request, indicating that the N4 session of the first terminal has been terminated or not.

[0190] Here, the first response can be understood as an N4 session end response.

[0191] Step 21: The ground SMF receives the first response, and sends a response to the seventh request to the ground AMF when the first response indicates that the N4 session of the first terminal has been terminated.

[0192] Here, since the seventh request can be understood as a session context update request, the response to the seventh request can be understood as a session context update response. The response to the seventh request can carry the CN tunnel information and QoS Profile (QoS policy) of the first satellite, etc.

[0193] Step 22: The ground AMF receives the response to the seventh request (update session context response) and sends a confirmation message of the first request to the base station on the first satellite through the gateway.

[0194] Here, the confirmation message of the first request may be understood as an N2 path switching confirmation or an N2 path switching confirmation message to confirm switching of the N2 path.

[0195] Step 23: The base station on the first satellite receives a confirmation message of the first request; the base station on the first satellite establishes an on-satellite N3 tunnel with the UPF on the first satellite based on the CN tunnel information, and instructs the base station on the second satellite to release the resources of the first terminal, so that the base station on the second satellite releases the resources occupied by the first terminal.

[0196] Step 24: The base station on the first satellite sends third information to the first terminal, where the third information indicates that the connection switching between the first terminal and the first satellite is completed.

[0197] Step 25: After receiving the third information, the first terminal sends a tenth information to the P-CSCF of the first terminal through the first satellite and the gateway, where the tenth information indicates that the connection switching between the first terminal and the first satellite is completed.

[0198] Here, the first terminal may send an intra-session call request (INVITE) or an update (UPDATE) message to the P-CSCF of the first terminal through the first satellite and the gateway, and the INVITE or UPDATE message carries the tenth information. The tenth information may be understood as switching history information, and the tenth information includes one or more of the following: an identifier of the first satellite, an identifier of the second satellite, and a third state, and the third state indicates that the connection switching between the first terminal and the first satellite is completed. The third state may be described as a connection change condition (completed).

[0199] Step 26: The P-CSCF of the first terminal receives the tenth message and sends the eleventh message to the P-CSCF of the second terminal through the ground I / S-CSCF. The eleventh message indicates that the address and port of the multimedia session between the second terminal and the first terminal are modified to the address and port of the AGW on the first satellite.

[0200] Here, after receiving the tenth information, the P-CSCF of the first terminal sends an intra-session INVITE or UPDATE message to the P-CSCF of the second terminal according to the tenth information, and the INVITE or UPDATE message carries the eleventh information, for example, the address and port of the multimedia session in the SDP of the INVITE or UPDATE message are modified to the address and port of the AGW on the first satellite. The address of the multimedia session can be described as a media address.

[0201] Step 27: The P-CSCF of the second terminal receives the eleventh information, and sends the eleventh information to the second terminal.

[0202] Here, the P-CSCF of the second terminal sends an intra-session INVITE or UPDATE message to the second terminal, and the address and port of the multimedia session in the SDP of the INVITE or UPDATE message are the address and port of the AGW on the first satellite.

[0203] After receiving the INVITE or UPDATE message, the second terminal returns a 200 response to the P-CSCF of the second terminal; the P-CSCF of the second terminal returns a 200 response to the P-CSCF of the first terminal through the ground I / S-CSCF. The P-CSCF of the first terminal sends a 200 response to the first terminal through the gateway and the first satellite. After receiving the 200 response, the first terminal sends an acknowledgment (ACK, Acknowledgement) to the P-CSCF of the first terminal through the first satellite and the gateway; the P-CSCF of the first terminal sends an ACK to the P-CSCF of the second terminal through the ground I / S-CSCF, and the P-CSCF of the second terminal sends an ACK to the second terminal. It should be noted that the address and port of the multimedia session in the 200 response are the address and port of the AGW on the first satellite, that is, the address of the multimedia session is the address of the AGW on the first satellite, and the port of the multimedia session is the port of the AGW on the first satellite.

[0204] Step 28: After receiving the 200 response, the P-CSCF of the first terminal sends sixth information to the AGW on the second satellite through the gateway, and the sixth information instructs the AGW on the second satellite to release the media resources occupied by the multimedia session of the first terminal.

[0205] Here, the P-CSCF of the first terminal may send the sixth information to the AGW on the second satellite, and then send a 200 response to the first terminal through the gateway and the first satellite, wherein the address and port of the multimedia session in the 200 response are the address and port of the AGW on the first satellite.

[0206] After receiving the 200 response, the first terminal saves the address and port of the AGW on the first satellite, or changes the media address and port of the multimedia session of the first terminal from the address and port of the AWG on the second satellite to the address and port of the AGW on the first satellite, thereby realizing the switching of the entire call (PDU session and multimedia session) of the first terminal.

[0207] It should be noted that when the first terminal switches from the UPF and AGW on the second satellite to the UPF and AGW on the first satellite, the session resources of the UPF and the media resources of the AGW on the second satellite can be released immediately, reducing the waste of limited network resources on the second satellite.

[0208] Figure 6Compared with the existing solutions, the corresponding embodiment adds a source base station on the source satellite to select the target satellite for switching based on satellite ephemeris data, the location information of the first terminal and the location information of the gateway. The ground AMF immediately notifies the ground SMF of the changes in the satellite network connection corresponding to the switching, so that the ground SMF can notify the ground P-CSCF of the changes in the satellite network connection corresponding to the switching through the ground PCF, thereby allowing the terminal and the satellite-to-ground network to instantly adjust the path of the user plane and multimedia sessions. Figure 6 The corresponding embodiments can complete the switching preparation (for example, the second satellite completes data synchronization with the first satellite) before the second satellite moves out of the communication range of the first terminal. When the satellite-borne base station switching is expected to occur, the satellite-to-ground network connection can be switched instantly and dynamically, thereby shortening the switching delay of the first terminal, achieving call continuity, and reducing the impact of communication interruptions on the poor user communication service experience, thereby improving the user experience; the session resources of the UPF and the media resources of the AGW on the second satellite can also be released instantly to reduce resource waste.

[0209] The above describes a switching method for the first terminal to perform inter-satellite switching in a scenario where the source satellite and the destination satellite support the Xn extended interface. Next, the following describes a switching method for the first terminal to perform inter-satellite switching in a scenario where the source satellite and the destination satellite do not support the Xn extended interface. Figure 7 As shown, in a scenario where the Xn extended interface is not supported between the source satellite and the destination satellite, a switching method for performing inter-satellite switching on the first terminal based on the N2 interface includes the following steps:

[0210] Step 1: The first terminal directly connects to the second satellite, and establishes an on-satellite PDU session through the second on-satellite base station and UPF, as well as through the ground gateway, ground AMF and SMF.

[0211] Here, base stations, UPFs and AWGs are deployed on both the first satellite and the second satellite. The first satellite and the second satellite include NGSOs. The second satellite is a source satellite of the first terminal, the base station on the second satellite is a source base station of the first terminal, and the UPF on the second satellite is a source UPF of the terminal. The first terminal is a calling terminal.

[0212] Step 2: The first terminal directly connects to the second satellite, and establishes a satellite-to-ground multimedia session, such as an IMS call or IMS session, with the second terminal through the base station, UPF and AGW on the second satellite, as well as through the ground gateway, ground P-CSCF, I / S-CSCF and other network functions.

[0213] Step 3: The first satellite moves into the communication range of the gateway, and the base station on the second satellite establishes a connection with the ground AMF through the gateway, for example, establishing an NGAP connection.

[0214] Here, the terrestrial AMF refers to the terrestrial AMF where the PDU session of the first terminal is located.

[0215] Step 4: The ground AMF selects the first satellite as the destination satellite of the first terminal based on the satellite ephemeris data, and establishes a connection with the base station on the first satellite; sends fifth information to the base station on the second satellite through the gateway, and the fifth information indicates that the communication service of the first terminal accessing the base station on the second satellite can be switched from the second satellite to the first satellite.

[0216] Here, the ground AMF can select the first satellite as the destination satellite of the first terminal based on the ephemeris data of the first satellite and the ephemeris data of the second satellite, and establish a connection with the base station on the first satellite; then, send the fifth information to the base station on the second satellite through the gateway. The fifth information can be understood as a connection establishment notification message, and the fifth information includes one or more of the following: an identifier of the first satellite, an identifier of the base station on the first satellite, and a second indication, and the second indication is used to indicate that the ground AMF has established a connection with the base station on the first satellite.

[0217] Step 5: The base station on the second satellite determines the switching preparation timing based on the satellite ephemeris data, the location information of the first terminal and the location information of the gateway; before the base station on the second satellite moves out of the communication range of the first terminal or before the switching preparation timing is reached, the base station on the second satellite sends a fifth request to the ground AMF through the gateway, and the fifth request is used to request to switch the communication service of the first terminal from the second satellite to the first satellite.

[0218] Here, the base station on the second satellite can determine the first time when the second satellite moves out of the communication range of the first terminal based on the satellite ephemeris data, the location information of the first terminal and the location information of the gateway; determine the switching preparation timing based on the first time, and the switching preparation timing is before the first time. Among them, the satellite ephemeris data at least includes the ephemeris data of the second satellite, and of course can also include the ephemeris data of other satellites except the second satellite. In the case where the satellite ephemeris data includes the ephemeris data of the second satellite and the ephemeris data of other satellites, the base station on the second satellite can determine the second time when one or more satellites except the second satellite enter the communication range of the gateway based on the satellite ephemeris data, the location information of the first terminal and the location information of the gateway; the switching preparation timing can be between the second time and the first time.

[0219] Before the base station on the second satellite moves out of the communication range of the first terminal or before the handover preparation timing is reached, the base station on the second satellite sends a fifth request to the ground AMF. The fifth request can be understood as a handover request, and the fifth request carries one or more of the following:

[0220] synchronization data from a base station on a second satellite to a base station on a first satellite;

[0221] an identification of a base station on the first satellite;

[0222] Information about the PDU session of the first terminal;

[0223] The identifier and / or address of the ground AMF where the PDU session of the first terminal is located.

[0224] Step 6: The ground AMF receives the fifth request and sends a sixth request to the ground SMF. The sixth request is used to request to update the context of the PDU session of the first terminal, carrying the identifier of the base station on the first satellite, the identifier of the PDU session of the first terminal, the switching type characterizing the inter-satellite switching, and the identifier of the first satellite.

[0225] Here, the sixth request may be understood as a session context update request or a PDU session context update request, and the identifier of the first satellite may be a satellite ID.

[0226] Step 7: The ground SMF receives the sixth request, selects the UPF on the first satellite as the destination UPF based on the identifier of the first satellite carried in the sixth request, and sends second information to the UPF on the first satellite through the gateway. The second information indicates that the ground SMF selects the UPF on the first satellite as the destination UPF for the first terminal.

[0227] Here, after receiving the sixth request, the ground SMF obtains the information carried by the sixth request from the sixth request, such as the identifier of the PDU session of the first terminal, the identifier of the base station on the first satellite, the switching type characterizing the inter-satellite switching, and the identifier of the first satellite; and selects the UPF on the first satellite as the destination UPF based on the identifier of the first satellite.

[0228] Step 8: The ground SMF sends a second request to the UPF on the first satellite through the gateway; the second request is used to request to establish an N4 session of the first terminal and carries AN tunnel information.

[0229] Here, the second request can be understood as an N4 session establishment request or a request to establish an N4 session.

[0230] Step 9: The UPF on the first satellite sends a response to the second request to the ground SMF through the gateway, and the response to the second request carries the CN tunnel information.

[0231] Here, the response to the second request can be understood as an N4 session establishment response or an establishment N4 session response.

[0232] Step 10: The ground SMF sends a response to the sixth request to the ground AMF.

[0233] Here, since the sixth request can be understood as a request to update the session context, the response to the sixth request can be understood as a response to update the session context; the response to the sixth request carries information such as the identifier of the PDU session of the first terminal, the CN tunnel and the address of the UPF on the first satellite.

[0234] Step 11: The ground AMF sends a third request to the base station on the first satellite through the gateway.

[0235] Here, the third request represents that the first terminal requests to switch from the base station on the second satellite to the base station on the first satellite, and the third request carries the source to destination transparent container data, CN tunnel information and N3 address information of the UPF on the first satellite. The third request can be understood as a switching request.

[0236] Step 12: The base station on the first satellite receives the third request and sends a confirmation message of the third request to the ground SMF through the gateway.

[0237] Here, the confirmation message of the third request carries the PDU session information of the first terminal, the AN tunnel information and the RAN N3 address information. The confirmation message of the third request can be understood as a handover request confirmation or a handover request confirmation message.

[0238] Step 13: The ground AMF receives a confirmation message of the third request and sends a sixth request to the ground SMF, where the sixth request is a request to update the session context.

[0239] Step 14: The SMF receives the sixth request, and sends a fourth request to the UPF on the first satellite through the gateway. The fourth request is used to request modification of the N4 session, and carries the AN tunnel information and the RAN N3 address information.

[0240] Step 15: The UPF on the first satellite receives the fourth request, establishes an N3 tunnel with the base station on the first satellite, and sends a response to the fourth request to the ground SMF through the gateway.

[0241] Here, the response to the fourth request can be understood as an N4 session update response or an N4 session modification response.

[0242] Step 16: The ground SMF receives a response to the fourth request and sends seventh information to the ground PCF, where the seventh information indicates that the PDU session connection of the first terminal is switched from the UPF on the second satellite to the UPF on the first satellite.

[0243] Here, the ground SMF may send a connection change notification message to the ground PCF, and the connection change notification message carries the seventh information; the seventh information includes one or more of the following: a connection change type characterizing an intersatellite connection change, an identifier of the first satellite, an address of the UPF on the first satellite, and a first state, wherein the first state characterizes an uncompleted change in the PDU session connection of the first terminal. The first state may be described as a connection change situation (in progress).

[0244] Step 17: The ground PCF receives the seventh information and saves the address of the UPF on the first satellite; based on the association relationship between the network functions established when the multimedia session is established, determines the P-CSCF of the first terminal, and sends the seventh information to the P-CSCF of the first terminal.

[0245] Step 18: The P-CSCF of the first terminal receives the seventh information, selects the AGW on the first satellite as the target AGW according to the identifier of the first satellite, and sends the fourth information to the AGW on the first satellite through the gateway, where the fourth information indicates that media resources are allocated to the first terminal.

[0246] Here, the fourth information indicates that the AGW on the first satellite allocates media resources for the multimedia session of the first terminal. When the AGW on the first satellite allocates media resources for the multimedia session of the first terminal, a message indicating that the media resource allocation is completed may be fed back to the P-CSCF of the first terminal.

[0247] Step 19: The P-CSCF of the first terminal sends the eighth information to the ground PCF, where the eighth information indicates confirmation that the PDU session connection of the first terminal can be switched from the UPF on the second satellite to the UPF on the first satellite.

[0248] Here, the eighth information may be understood as a confirmation message of the connection change notification message.

[0249] Step 20: The ground PCF receives the eighth information and sends the eighth information to the ground SMF.

[0250] Step 21: The ground SMF receives the eighth information and sends a response to the sixth request (update session context response) to the ground AMF.

[0251] Step 22: The ground AMF receives a response to the sixth request, and sends a switching command to the base station on the second satellite through the gateway, where the switching command instructs to switch the first terminal from the base station on the second satellite to the destination cell of the base station on the first satellite.

[0252] Step 23: The base station on the first satellite receives the switching command, sends the switching command to the first terminal, and the base station resources on the second satellite release the resources occupied by the first terminal.

[0253] Step 24: The first terminal receives the handover command, switches to the target cell according to the handover command, and sends a handover confirmation to the base station on the first satellite.

[0254] Here, the handover confirmation is also referred to as a handover confirmation message. The handover command carries the target cell, and the target cell may be a cell of a base station on the first satellite.

[0255] Step 25: The base station on the first satellite receives the switching confirmation and sends a switching notification to the ground AMF through the gateway, indicating that the switching is successful.

[0256] Here, the switching notification is also called a switching notification message, indicating that the first terminal has successfully switched to the base station in the first satellite direction.

[0257] Step 26: The ground AMF receives the switching notification and sends a sixth request to the ground SMF, where the sixth request is used to request an update of the context of the PDU session of the first terminal.

[0258] Here, the sixth request can be understood as a PDU session context update request or an update session context request, carrying information such as a switching completion indication.

[0259] Step 27: The ground SMF receives the sixth request sent by the ground AMF, and sends the eighth request to the UPF on the second satellite through the gateway, where the eighth request is used to request to end the N4 session of the first terminal.

[0260] Here, the eighth request can be understood as an N4 session end request.

[0261] Step 28: The UPF on the second satellite receives the eighth request and sends a first response to the ground SMF through the gateway. The first response indicates whether the N4 session of the first terminal has been terminated or not.

[0262] Here, the UPF on the second satellite receives the eighth request and ends the N4 session of the first terminal.

[0263] Step 29: The ground SMF receives the first response and sends a response to the sixth request to the ground AMF.

[0264] Here, the response to the sixth request may be understood as a session context update response.

[0265] Step 30: The ground SMF sends ninth information to the ground PCF, and the ninth information indicates that the PDU session connection of the first terminal has been switched from the UPF on the second satellite to the UPF on the first satellite.

[0266] Here, after the ground SMF receives the first response, the ground SMF sends a connection change notification to the ground PCF. The connection change notification carries the ninth information. The connection change notification is also called a connection change notification message.

[0267] The ninth information includes one or more of the following: a connection change type characterizing an intersatellite connection change, an identifier of the first satellite, an address of a UPF on the first satellite, and a second state, wherein the second state characterizes that a change in the PDU session connection of the first terminal has been completed. The second state can be described as a connection change condition (completed).

[0268] Step 31: The ground PCF receives the ninth information, determines the P-CSCF of the first terminal based on the association relationship between network functions established when the multimedia session is established, and sends the ninth information to the P-CSCF of the first terminal.

[0269] Step 32: The P-CSCF of the first terminal receives the ninth information, and sends the eleventh information to the P-CSCF of the second terminal through the I / S-CSCF on the ground. The eleventh information indicates that the address and port of the multimedia session between the second terminal and the first terminal are modified to the address and port of the AGW on the first satellite.

[0270] Here, the P-CSCF of the first terminal can send an intra-session INVITE or UPDATE message to the P-CSCF of the second terminal based on the ninth information, and the INVITE or UPDATE message carries the eleventh information, for example, the address and port of the multimedia session in the SDP of the INVITE or UPDATE message are modified to the address and port of the AGW on the first satellite. The address of the multimedia session can be described as a media address.

[0271] Step 33: The P-CSCF of the second terminal receives the eleventh information, and sends the eleventh information to the second terminal.

[0272] Here, the second terminal receives the eleventh information and sends a 200 response to the P-CSCF of the second terminal; the P-CSCF of the second terminal sends a 200 response to the P-CSCF of the first terminal through the ground I / S-CSCF.

[0273] Specifically, the P-CSCF of the second terminal receives an INVITE or UPDATE message within the session, and the P-CSCF of the second terminal sends an INVITE or UPDATE message within the session to the second terminal, and the address and port of the multimedia session in the SDP of the INVITE or UPDATE message are the address and port of the AGW on the first satellite. After receiving the INVITE or UPDATE message, the second terminal returns a 200 response to the P-CSCF of the second terminal; the P-CSCF of the second terminal returns a 200 response to the P-CSCF of the first terminal through the ground I / S-CSCF. After receiving the 200 response, the P-CSCF of the first terminal sends an ACK to the P-CSCF of the second terminal through the ground I / S-CSCF, and the P-CSCF of the second terminal sends an ACK to the second terminal.

[0274] It should be noted that, when the P-CSCF of the second terminal receives the INVITE or UPDATE message in the session, it saves the address and port of the AGW on the first satellite, or changes the media address and port of the multimedia session between the second terminal and the first terminal from the address and port of the AWG on the second satellite to the address and port of the AGW on the first satellite; when the P-CSCF of the second terminal receives the 200 response sent by the second terminal, it returns a 200 response to the P-CSCF of the first terminal through the ground I / S-CSCF. The address and port of the multimedia session in the 200 response are the address and port of the AGW on the first satellite.

[0275] Step 34: The P-CSCF of the first terminal sends the eleventh information to the first terminal through the gateway and the UPF on the first satellite. The eleventh information indicates that the port and address of the multimedia session of the first terminal are modified to the address and port of the AGW on the first satellite.

[0276] Here, after the P-CSCF of the first terminal receives the 200 response, the P-CSCF of the first terminal sends an intra-session INVITE or UPDATE message to the first terminal through the gateway and the UPF on the first satellite. The intra-session INVITE or UPDATE message carries the eleventh information. For example, the address and port of the multimedia session in the SDP of the INVITE or UPDATE message are modified to the address and port of the AGW on the first satellite to complete the update of the media address and port of the multimedia session of the first terminal.

[0277] Step 35: The P-CSCF of the first terminal sends the twelfth information to the ground SMF through the ground PCF. The twelfth information indicates confirmation that the multimedia session of the first terminal has been switched from the UPF on the second satellite to the UPF on the first satellite.

[0278] Here, the twelfth information can be understood as a connection change notification confirmation.

[0279] Step 36: The P-CSCF of the first terminal sends sixth information to the AGW on the second satellite through the gateway, where the sixth information instructs the AGW on the second satellite to release the media resources of the first terminal.

[0280] Here, after receiving the 200 response, the P-CSCF of the first terminal sends sixth information to the AGW on the second satellite through the gateway, so that the AGW on the second satellite releases the media resources of the multimedia session of the first terminal.

[0281] Figure 7Compared with the existing scheme, the corresponding embodiment adds a ground AMF to select the target satellite for switching based on satellite ephemeris data. The ground AMF will immediately notify the ground SMF of the changes in the satellite network connection corresponding to the switching, so that the ground SMF can notify the ground P-CSCF of the changes in the satellite network connection corresponding to the switching through the ground PCF, thereby enabling the terminal and the satellite-to-ground network to instantly adjust the path of the user plane and multimedia sessions. Figure 7 The corresponding embodiments can complete the switching preparation (for example, the second satellite completes data synchronization with the first satellite) before the second satellite moves out of the communication range of the first terminal. When the satellite-borne base station switching is expected to occur, the satellite-to-ground network connection can be switched instantly and dynamically, thereby shortening the switching delay of the first terminal, achieving call continuity, and reducing the impact of communication interruptions on the poor user communication service experience, thereby improving the user experience; the session resources of the UPF and the media resources of the AGW on the second satellite can also be released instantly to reduce resource waste.

[0282] The above respectively introduces the switching method for inter-satellite switching of the first terminal in the scenario where the Xn extended interface is supported or not supported between the source satellite and the destination satellite; next, the operations performed by the first satellite, the second satellite, the ground AMF, the ground SMF, the ground PCF and the P-CSCF of the first terminal during the inter-satellite switching of the first terminal are respectively introduced.

[0283] The embodiment of the present application provides a switching method, which is applied to a first satellite, the first satellite is a destination satellite, at least a first network device and a first network function are deployed on the first satellite, the first satellite includes an NGSO satellite, the first network device includes a base station, and the first network function includes a UPF and / or a network function having the same function as the UPF. Figure 8 As shown, the method includes:

[0284] Step 801: Receive first information sent by a second network device on a second satellite to the first network device.

[0285] The first information is sent before the second network device moves out of the communication range of the first terminal connected to the second network device, representing synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite.

[0286] Here, the first satellite supports an Xn extended interface with the second satellite, the second satellite establishes a connection with the first satellite through an intersatellite link, at least a second network device and a third network function are deployed on the second satellite, the second network device includes a base station, and the third network function includes UPF and / or a network function with the same function as UPF; the first terminal is directly connected to the second satellite, and an on-board PDU session is established through the second network device and the third network function on the second satellite, as well as the gateway, the fourth network function on the ground and the second network function on the ground. The second satellite is the source satellite of the first terminal, the second satellite includes an NGSO satellite, the first terminal is a calling terminal, the gateway is also called a ground gateway, the fourth network function on the ground includes AMF and / or a network function with the same function as AMF, and the second network function on the ground includes SMF and / or a network function with the same function as SMF. In actual application, the first network function and the third network function are UPF, the second network function on the ground is SMF, and the fourth network function on the ground is AMF.

[0287] The first satellite moves to the communication range of the gateway, and the first network device on the first satellite establishes an NGAP connection through the gateway with the fourth network function where the PDU session of the first terminal is located.

[0288] Before moving out of the communication range of the first terminal, the second network device on the second satellite selects the first satellite as the destination satellite of the first terminal and sends the first information to the first network device on the first satellite, with the second satellite being the source satellite; the first satellite receives the first information sent by the second network device on the second satellite to the first network device on the first satellite, and the first satellite sends the first information to the first network device on the first satellite. Synchronous data can be understood as data related to the first terminal on the first satellite.

[0289] In the case where the Xn extended interface is supported between the first satellite and the second satellite, in order to improve the data transmission efficiency between the first satellite and the second satellite, in one embodiment, the receiving the first information sent by the second network device on the second satellite to the first network device includes:

[0290] First information sent to the first network device by a second network device on the second satellite is received through a link between the first satellite and the second satellite.

[0291] Here, the link between the first satellite and the second satellite can be understood as an inter-satellite link.

[0292] In order to ensure the continuity of the communication service of the first terminal, in one embodiment, the first information includes information of the PDU session of the first terminal, and an identifier and / or address of a fourth network function where the PDU session of the first terminal is located.

[0293] In the case where the Xn extended interface is supported between the first satellite and the second satellite, in order to ensure the continuity of the PDU session of the first terminal, before the first terminal switches from the second network device of the second satellite to the first network device on the first satellite, the first network device on the first satellite establishes a connection with the fourth network function where the PDU session of the first terminal is located. Based on this, in one embodiment, the method further includes:

[0294] A first indication issued by the first network device is sent to the second network device, where the first indication is used to indicate that the first network device has established a connection with a fourth network function where the PDU session of the first terminal is located.

[0295] Here, when the first network device on the first satellite establishes an NGAP connection with the fourth network function where the PDU session of the first terminal is located through the gateway, the first network device on the first satellite generates and issues a first indication, and the first satellite sends the first indication issued by the first network device to the second network device on the second satellite. The first indication may be carried in a connection establishment notification message; the connection establishment notification message is sent when the first network device on the first satellite establishes an NGAP connection with the fourth network function where the PDU session of the first terminal is located through the gateway.

[0296] Step 802: Receive second information sent by a second network function on the ground to the first network function through a gateway.

[0297] The second information represents that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

[0298] Here, when the first terminal switches from the second network function on the second satellite to the first satellite, the second network function on the ground queries the first network function on the first satellite, selects the first network function on the first satellite as the destination network function of the first terminal, and sends second information to the first network function on the first satellite through the gateway; the first satellite receives the second information sent by the second network function on the ground to the first network function on the first satellite through the gateway, and the first satellite sends the second information to the first network function on the first satellite.

[0299] In the case where the Xn extended interface is supported between the first satellite and the second satellite, in order to ensure the continuity of the PDU session of the first terminal, when the first terminal switches from the second network device on the second satellite to the first network device on the first satellite, the first network device on the first satellite needs to request the fourth network function where the PDU session of the first terminal is located to switch the N2 path. Based on this, in one embodiment, after receiving the first information sent by the second network device on the second satellite to the first network device, the method further includes:

[0300] When the first terminal switches from the second network device to the first network device, a first request is sent to a fourth network function where the PDU session of the first terminal is located through the gateway; wherein,

[0301] The first request is used to request switching of the N2 path, and carries a switching type representing inter-satellite switching, an identifier of the first satellite, and N2 SM information.

[0302] Here, the first request may be understood as an N2 path switching request, and the N2 SM information includes information of the PDU session of the first terminal, N3 tunnel information, location information of the first terminal, and the like.

[0303] In order to ensure the continuity of the PDU session of the first terminal, when the first terminal switches from the second network device on the second satellite to the first network device on the first satellite, the second network function on the ground needs to update the context of the PDU session of the first terminal and request the first network function on the first satellite to establish an N4 session for the first terminal. Based on this, in one embodiment, after receiving the first information sent by the second network device on the second satellite to the first network device, the method further includes:

[0304] Receive a second request sent by the second network function to the first network function through the gateway; wherein the second request is used to request establishment of an N4 session of the first terminal and carries AN tunnel information.

[0305] Here, in the case where the Xn extended interface is supported or not supported between the first satellite and the second satellite, after the first satellite receives the second request sent by the second network function on the ground to the first network function on the first satellite through the gateway, the first satellite sends the second request to the first network function on the first satellite, and the first network function on the first satellite returns a response to the second request; the first satellite sends the response to the second request returned by the first network function to the second network function on the ground through the gateway, and the response to the second request carries CN tunnel information.

[0306] The second request may be understood as a request to establish an N4 session or a request to establish an N4 session; the response to the second request establishes an N4 session response or an N4 session establishment response, which is used to indicate success or failure in establishing the N4 session of the first terminal.

[0307] When the first network function on the first satellite establishes an N4 session of the first terminal, and the ground network has changed the connection of the first terminal from the second satellite to the first satellite, the second network function on the ground sends an update session context response to the fourth network function where the PDU session of the first terminal is located, and the fourth network function sends an N2 path switching confirmation message to the first network device on the first satellite, so that the first network device on the first satellite notifies the second network device on the second satellite to release the resources related to the first terminal, and notifies the first terminal that the connection switching is completed, so as to facilitate the first terminal to learn that the connection of the first terminal has been successfully switched from the second satellite to the first satellite. Based on this, in one embodiment, the method also includes:

[0308] Upon receiving a confirmation message of the first request sent by the fourth network function where the PDU session of the first terminal is located to the first network device through the gateway, third information is sent to the first terminal, wherein the third information indicates that the connection switching between the first terminal and the first satellite is completed.

[0309] Here, the confirmation message of the first request indicates confirmation that the N2 path switching of the first terminal is completed.

[0310] In the case where the Xn extended interface is supported or not supported between the first satellite and the second satellite, in order to ensure the continuity of the multimedia session of the first terminal, in one embodiment, a fifth network function related to the multimedia session is further deployed on the first satellite, and the method further includes:

[0311] Receive fourth information sent by a sixth network function on the ground to the fifth network function through the gateway, the sixth network function represents a network function accessed by the multimedia session of the first terminal, and the fourth information indicates allocation of media resources for the first terminal.

[0312] Here, the fifth network function includes AGW and / or SBC-U, and the sixth network function includes P-CSCF and / or SBC-C; when the fifth network function includes AGW, the sixth network function includes P-CSCF; when the fifth network function includes SBC-U, the sixth network function includes SBC-C.

[0313] When a fifth network function related to multimedia sessions is also deployed on the first satellite, and a seventh network function related to multimedia sessions is also deployed on the first satellite, the first terminal establishes a satellite-to-ground multimedia session, such as a satellite-to-ground IMS session or a satellite-to-ground IMS call, with the second terminal through the second network device, the third network function and the seventh network function on the second satellite, as well as the gateway, the sixth network function on the ground, the I / S-CSCF and other network functions; the seventh network function on the first satellite includes AGW and / or SBC-U.

[0314] When the first terminal switches from the second network device on the second satellite to the first network device on the first satellite, and the first network function on the first satellite establishes an N4 session for the first terminal, the second network function on the ground sends seventh information to the sixth network function on the ground through the eighth network function on the ground, the eighth network function includes PCF and / or a network function with the same function as PCF, the seventh information indicates that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, and the seventh information can be carried in the connection change notification message; the sixth network function on the ground sends fourth information to the fifth network function on the first satellite through the gateway; the first satellite receives the fourth information sent by the sixth network function on the ground to the fifth network function on the first satellite through the gateway, the first satellite sends the fourth information to the fifth network function on the first satellite, and allocates multimedia resources to the first terminal, and the multimedia resources are used for the multimedia session.

[0315] In the case that the Xn extended interface is not supported between the first satellite and the second satellite, in order to ensure the continuity of the communication service of the first terminal, in one embodiment, the method further includes one or more of the following:

[0316] receiving a third request sent by a fourth network function where the PDU session of the first terminal is located to the first network device through the gateway;

[0317] Sending a confirmation message of the third request sent by the first network device to the fourth network function through the gateway;

[0318] receiving a fourth request sent by the second network function to the first network function through the gateway; wherein:

[0319] The third request represents that the first terminal requests to switch from the second network device to the first network device, and the third request carries source to destination transparent container data, CN tunnel information and N3 address information of the first network function; the confirmation message of the third request carries the PDU session information of the first terminal, AN tunnel information and RANN3 address information; the fourth request is used to request to modify the N4 session, carrying AN tunnel information and RAN N3 address information.

[0320] Here, when the Xn extended interface is not supported between the first satellite and the second satellite, after the fourth network function where the PDU session of the first terminal is located establishes an NGAP connection with the first network device on the first satellite, it notifies the second network device on the second satellite that the fourth network function has established a connection with the first network device on the first satellite; the second network device on the second satellite sends a third request to the fourth network function, and the third request can be understood as a switching request; the fourth network function sends the third request to the first network device on the first satellite; the first satellite receives the third request sent by the fourth network function to the first network device on the first satellite, and sends the third request to the first network device on the first satellite.

[0321] When the first network device on the first satellite receives the third request, it generates and sends a confirmation message of the third request, that is, a switching request confirmation message; the first satellite sends the confirmation message of the third request sent by the first network device on the first satellite to the fourth network function through the gateway.

[0322] Upon receiving a confirmation message for the third request, the fourth network function sends a sixth request to the second network function on the ground, where the sixth request is used to request an update of the context of the PDU session of the first terminal, and carries an identifier of the first network device, an identifier of the PDU session of the first terminal, a switching type representing inter-satellite switching, and an identifier of the first satellite; the second network function on the ground receives the sixth request, updates the context of the PDU session of the first terminal, and sends a fourth request to the first network function on the first satellite through the gateway to request modification of the N4 session; the first satellite receives the fourth request sent by the second network function on the ground to the first network function on the first satellite, and sends the fourth request to the first network function on the first satellite; the first network function on the first satellite receives the fourth request and modifies the N4 session of the first terminal.

[0323] The sixth request may be understood as a session context update request or a PDU session context update request, and the fourth request may be understood as an N4 session modification request or an N4 session update request.

[0324] Correspondingly, an embodiment of the present application further provides a switching method, which is applied to a second satellite, on which at least a second network device and a third network function are deployed, the second network device includes a base station, the third network function includes a UPF and / or a network function having the same function as the UPF, and the second satellite is a source satellite of the first terminal. Fig. 9 As shown, the method includes:

[0325] Step 901: Send first information sent by the second network device to the first network device on the first satellite, or receive fifth information sent by the fourth network function where the PDU session of the first terminal is located to the second network device through the gateway.

[0326] Among them, the first information is sent before the second network device moves out of the communication range of the first terminal connected to the second network device, indicating that the communication service of the first terminal is switched from the second satellite to the synchronization data of the first satellite; the fifth information is sent after the fourth network function establishes a connection with the first network device on the first satellite, indicating that the communication service of the first terminal can be switched from the second satellite to the first satellite.

[0327] Here, in the case where the Xn extended interface is supported between the first satellite and the second satellite, before the second network device of the second satellite moves out of the communication range of the first terminal, the second network device on the second satellite needs to send first information to the first network device on the first satellite, and the second satellite sends the first information sent by the second network device on the second satellite to the first network device on the first satellite, thereby synchronizing the relevant data of the first terminal on the second satellite to the first satellite.

[0328] In order to ensure the continuity of the PDU session of the first terminal, in one embodiment, the first information includes information of the PDU session of the first terminal, and an identifier and / or address of a fourth network function where the PDU session of the first terminal is located.

[0329] When the Xn extended interface is not supported between the first satellite and the second satellite, after the fourth network function where the PDU session of the first terminal is located establishes a connection with the first network device on the first satellite, the fifth information is sent to the first network device on the first satellite through the gateway; the first satellite receives the fifth information sent by the fourth network function through the gateway, and sends the fifth information to the first network device on the first satellite.

[0330] In order to facilitate the second network device on the second satellite to learn the destination satellite or destination network device of the first terminal so as to initiate a handover request, in one embodiment, the fifth information includes one or more of the following:

[0331] an identifier of the first satellite;

[0332] an identifier of the first network device;

[0333] A second indication, where the second indication is used to indicate that the fourth network function has established a connection with the first network device.

[0334] In the case where the Xn extended interface is supported between the first satellite and the second satellite, in order to improve the data transmission efficiency between the first satellite and the second satellite, in one embodiment, sending the first information sent by the second network device to the first network device on the first satellite includes:

[0335] The first information sent by the second network device is sent to the first network device on the first satellite through a link between the first network device on the first satellite and the second network device on the second satellite.

[0336] Here, the link between the first network device on the first satellite and the second network device on the second satellite is based on a link established between the first satellite and the second satellite supporting an Xn extended interface, and the Xn extended interface is set on the link between the first satellite and the second satellite.

[0337] In the case where the Xn extended interface is supported between the first satellite and the second satellite, in order to ensure the continuity of the PDU session of the first terminal, before the first terminal switches from the second network device of the second satellite to the first network device on the first satellite, the first network device on the first satellite needs to establish a connection with the fourth network function where the PDU session of the first terminal is located, and notify the second network device on the second satellite so that the second network device on the second satellite synchronizes the relevant data of the first terminal to the first network device on the first satellite. Based on this, in one embodiment, before sending the first information sent by the second network device to the first network device on the first satellite, the method also includes:

[0338] Receive a first indication sent by the first network device to the second network device, where the first indication is used to indicate that the first network device has established a connection with a fourth network function where a PDU session of the first terminal is located.

[0339] In the case where the Xn extended interface is supported between the first satellite and the second satellite, in order to ensure the continuity of the communication service of the first terminal, in one embodiment, before sending the first information sent by the second network device to the first network device on the first satellite, the method further includes:

[0340] Determining a handover preparation timing based on satellite ephemeris data, location information of the first terminal, and location information of the gateway;

[0341] Before the second network device moves out of the communication range of the first terminal or before the switching preparation timing is reached, the first satellite is selected as the destination satellite of the first terminal.

[0342] Here, the second network device on the second satellite can determine the first time when the second satellite moves out of the communication range of the first terminal based on the satellite ephemeris data, the location information of the first terminal and the location information of the gateway; determine the switching preparation timing based on the first time, and the switching preparation timing is before the first time. The satellite ephemeris data at least includes the ephemeris data of the second satellite, and of course can also include the ephemeris data of other satellites except the second satellite. In the case where the satellite ephemeris data includes the ephemeris data of the second satellite and the ephemeris data of other satellites, the second network device on the second satellite can also determine the second time when one or more satellites other than the second satellite enter the communication range of the gateway based on the satellite ephemeris data, the location information of the first terminal and the location information of the gateway, and / or determine the third time when one or more satellites other than the second satellite enter the communication range of the first terminal; when the second time corresponding to any satellite is earlier than the first time, or when the second time and the third time corresponding to any satellite are both earlier than the first time, the satellite is determined as a candidate first satellite, and the switching preparation timing can be between the second time and the first time, or the switching preparation time can be between the third time and the first time; that is, before the second satellite moves out of the communication range of the first terminal, one or more satellites entering the communication range of the gateway can be determined as candidate first satellites, and the candidate first satellite can be understood as a candidate destination satellite of the first terminal.

[0343] Before the second network device on the second satellite moves out of the communication range of the first terminal or before the switching preparation timing is reached, the second satellite selects the first satellite as the destination satellite of the first terminal, or the second network device on the second satellite selects the first satellite as the destination satellite of the first terminal, and the second network device on the second satellite sends the first information to the first network device on the first satellite.

[0344] Before the switching preparation timing is reached, or when the switching preparation timing is reached, the second network device on the second satellite initiates a switch based on the satellite ephemeris data and the measurement report reported by the first terminal, and sends an RRC reconfiguration message to the first terminal. The RRC reconfiguration message carries information about the cell of the first network device on the first satellite, which can be understood as the destination cell of the first terminal.

[0345] When the first terminal receives the RRC reconfiguration message, it switches to the first network device on the first satellite based on the information carried in the RRC reconfiguration message, and sends an RRC reconfiguration completion message to the first network device on the first satellite.

[0346] In the case where the Xn extended interface is not supported between the first satellite and the second satellite, in order to ensure the continuity of the PDU session of the first terminal, the second network device on the second satellite needs to determine the switching preparation timing, and initiate a switching to the fourth network function where the PDU session of the first terminal is located before the second network device moves out of the communication range of the first terminal or before reaching the determined switching preparation timing, so that the fourth network function requests the second network function on the ground to update the context of the PDU session of the first terminal. Based on this, in one embodiment, after receiving the fifth information sent by the fourth network function where the PDU session of the first terminal is located to the second network device through the gateway, the method also includes:

[0347] Determining a handover preparation timing based on satellite ephemeris data, location information of the first terminal, and location information of the gateway;

[0348] Before the second network device moves out of the communication range of the first terminal or before the switching preparation timing is reached, a fifth request issued by the second network device is sent to the fourth network function through the gateway station, and the fifth request is used to request to switch the communication service of the first terminal from the second satellite to the first satellite.

[0349] Here, in the case where the Xn extended interface is not supported between the first satellite and the second satellite, the second satellite or the second network device on the second satellite determines the handover preparation timing based on the satellite ephemeris data, the location information of the first terminal and the location information of the gateway. The implementation process of determining the handover preparation timing is described above and will not be repeated here. The fifth request can be understood as a handover request.

[0350] In order to switch the PDU session of the first terminal from the first satellite to the second satellite, in one embodiment, the fifth request carries one or more of the following:

[0351] Synchronous data from the second network device to the first network device;

[0352] an identifier of the first network device;

[0353] Information about the PDU session of the first terminal;

[0354] The identifier and / or address of the fourth network function where the PDU session of the first terminal is located.

[0355] Here, the identifier and / or address of the fourth network function where the PDU session of the first terminal is located can be used by the network function that receives the fifth request to determine whether to process the fifth request; if the identifier and / or address of the network function that receives the fifth request is the same as the identifier and / or address of the fourth network function carried by the fifth request, the fifth request is processed.

[0356] In the scenario where the Xn extended interface is not supported between the first satellite and the second satellite, when the first network function on the first satellite establishes the N4 session of the first terminal, and the ground network has changed the connection of the first terminal from the second satellite to the first satellite, the sixth network function on the ground needs to instruct the seventh network function on the second satellite to release the multimedia resources of the first terminal to reduce the waste of multimedia resources on the second satellite. Based on this, in one embodiment, the second satellite is also deployed with a seventh network function related to the multimedia session, and after receiving the fifth information sent by the fourth network function where the PDU session of the first terminal is located through the gateway, the method further includes:

[0357] Receive sixth information sent by a sixth network function on the ground to the seventh network function through the gateway, the sixth network function representing the network function accessed by the multimedia session of the first terminal, and the sixth information instructing the seventh network function to release the media resources of the first terminal.

[0358] Here, the second satellite receives the sixth information sent by the sixth network function on the ground to the seventh network function on the second satellite through the gateway, and forwards the received sixth information to the seventh network function on the second satellite, so that the seventh network function on the second satellite releases the multimedia resources occupied by the first terminal.

[0359] The sixth network function is the P-CSCF or SBC-C where the multimedia session of the first terminal is located, that is, the P-CSCF or SBC-C to which the first terminal is connected; the seventh network function on the second satellite includes AGW and / or SBC-U.

[0360] Correspondingly, an embodiment of the present application also provides a switching method, which is applied to the fourth network function on the ground, and the fourth network function on the ground includes AMF and / or a network function with the same function as AMF.

[0361] like Fig.10 As shown, the method includes:

[0362] Step 1001: When the fourth network function establishes a connection with a first network device on a first satellite, fifth information is sent to a second network device on a second satellite through a gateway, and the fifth information indicates that a communication service of a first terminal accessing the second network device can be switched from the second satellite to the first satellite.

[0363] Here, in a scenario where the Xn extended interface is not supported between the first satellite and the second satellite, when the fourth network function on the ground establishes a connection with the first network device on the first satellite, the fifth information is sent to the second network device on the second satellite through the gateway. For example, when the fourth network function on the ground establishes a communication connection with the first network device on the first satellite, before the second satellite moves out of the communication range of the first terminal, the fifth information is sent to the second network device on the second satellite through the gateway.

[0364] The fifth information may be carried in the connection establishment notification message. The fourth ground network function refers to the network function where the PDU session of the first terminal is located, such as the ground AMF where the PDU session of the first terminal is located.

[0365] In order to facilitate the first terminal to initiate a handover to the fourth network function on the ground based on the fifth request, in one embodiment, the fifth information includes one or more of the following:

[0366] an identifier of the first satellite;

[0367] an identifier of the first network device;

[0368] A second indication, where the second indication is used to indicate that the fourth network function has established a connection with the first network device.

[0369] Before the fourth network function on the ground sends the fifth information, it is necessary to first select the first satellite as the destination satellite of the first terminal and establish a connection with the first satellite. In one embodiment, before sending the fifth information to the second network device on the second satellite through the gateway, the method further includes:

[0370] Based on the satellite ephemeris data, the first satellite is selected as the destination satellite of the first terminal, and a connection is established with the first network device on the first satellite. Here, the fourth network function on the ground can select the first satellite as the destination satellite of the first terminal based on the ephemeris data of the first satellite and the ephemeris data of the second satellite, and establish a connection with the first network device on the first satellite; for example, before the first satellite enters the communication range of the first terminal and before the second satellite moves out of the communication range of the first terminal, the first satellite is selected as the destination satellite of the first terminal, and a connection is established with the first network device on the first satellite.

[0371] In a scenario where the Xn extended interface is not supported between the first satellite and the second satellite, in order to ensure the continuity of the PDU session of the first terminal, after the first terminal receives the fifth information, it is necessary to initiate a handover to the fourth network function on the ground. Based on this, in one embodiment, after sending the fifth information to the second network device on the second satellite through the gateway, the method further includes:

[0372] A fifth request is received, which is sent by the second network device through a gateway, where the fifth request is used to request to switch the communication service of the first terminal from the second satellite to the first satellite.

[0373] Here, before moving out of the communication range of the first terminal, the second network device on the second satellite sends a fifth request to the fourth network function on the ground through the gateway, and the fifth request can be understood as a switching request; the fourth network function on the ground receives the fifth request.

[0374] In order to ensure the continuity of the PDU session of the first terminal, in one embodiment, the fifth request carries one or more of the following:

[0375] Synchronous data from the second network device to the first network device;

[0376] an identifier of the first network device;

[0377] Information about the PDU session of the first terminal;

[0378] The identifier and / or address of the fourth network function where the PDU session of the first terminal is located.

[0379] In order to switch the PDU session of the first terminal from the second network device on the second satellite to the first network device on the first satellite, the fourth network function on the ground needs to request the second network function on the ground to update the context of the PDU session of the first terminal after receiving the fifth request. Based on this, in one embodiment, after receiving the fifth request sent by the second network device through the gateway, the method further includes:

[0380] A sixth request is sent to the second network function on the ground, wherein the sixth request is used to request an update of the context of the PDU session of the first terminal, carrying an identifier of the first network device, an identifier of the PDU session of the first terminal, a switching type characterizing inter-satellite switching, and an identifier of the first satellite.

[0381] Here, the sixth request may be understood as a session context update request or a PDU session context update request. The second network function on the ground includes an SMF and / or a network function having the same function as the SMF.

[0382] In a scenario where the Xn extended interface is supported between the first satellite and the second satellite, after the first terminal switches to the first network device on the first satellite, the first network device on the first satellite needs to request the fourth network function on the ground where the PDU session of the first terminal is located to switch the N2 path. Based on this, in one embodiment, the method further includes:

[0383] Receive a first request sent by the first network device through the gateway; wherein the first request is sent when the first terminal switches from the second network device to the first network device, and the first request is used to request switching of the N2 path, carrying a switching type characterizing inter-satellite switching, an identifier of the first satellite, and N2 SM information.

[0384] Here, the first request may be understood as an N2 path switching request; the N2 SM information includes at least the information of the PDU session of the first terminal, and may also include N3 tunnel information and location information of the first terminal.

[0385] In order to ensure the continuity of the PDU session of the first terminal, the fourth network function on the ground needs to request the second network function on the ground to update the context of the PDU session of the first terminal after receiving the first request. Based on this, in one embodiment, after receiving the first request sent by the first network device through the gateway, the method further includes:

[0386] A seventh request is sent to the second network function on the ground, wherein the seventh request is used to request updating the context of the PDU session of the first terminal, carrying N2 SM information, a switching type representing inter-satellite switching, and an identifier of the first satellite.

[0387] Here, the seventh request may be understood as a session context update request or a PDU session context update request.

[0388] Correspondingly, the embodiment of the present application further provides a switching method, which is applied to a second network function on the ground, where the second network function on the ground includes an SMF and / or a network function having the same function as the SMF, such as Fig.11 As shown, the method includes:

[0389] Step 1101: Receive the sixth request or the seventh request sent by the fourth network function on the ground.

[0390] Among them, the sixth request and the seventh request are used to request to update the context of the PDU session of the first terminal, and carry at least the identifier of the PDU session of the first terminal, the switching type representing the inter-satellite switching and the identifier of the first satellite, and the first terminal represents the terminal requesting to switch the communication service from the second satellite to the first satellite.

[0391] Here, in a scenario where the Xn extended interface is not supported between the first satellite and the second satellite, a sixth request sent by the fourth network function on the ground is received, and the sixth request carries the identifier of the first network device on the first satellite, the identifier of the PDU session of the first terminal, the switching type representing the inter-satellite switching, and the identifier of the first satellite. In a scenario where the Xn extended interface is supported between the first satellite and the second satellite, a seventh request sent by the fourth network function on the ground is received, and the seventh request carries the switching type representing the inter-satellite switching, the identifier of the first satellite, and N2 SM information, and the N2 SM information includes at least information about the PDU session of the first terminal.

[0392] Step 1102: Send second information to the first network function on the first satellite through the gateway, where the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

[0393] Here, based on the sixth request or the seventh request, the second information is sent to the first network function on the first satellite through the gateway. Specifically, after receiving the sixth request or the seventh request, based on the information carried by the sixth request or the information carried by the seventh request, the first network function on the first satellite is selected as the destination network function of the first terminal, and the second information is sent to the first network function on the first satellite through the gateway; for example, based on the identifier of the first satellite, the first network function on the first satellite is queried, and the first network function on the first satellite is selected as the destination network function of the first terminal. In actual application, the first network function can be a UPF.

[0394] Before sending the second information, the second information needs to be generated first. Based on this, in one embodiment, the method further includes:

[0395] generating the second information based on the information carried in the sixth request; or

[0396] The second information is generated based on the information carried by the seventh request.

[0397] Here, the second information may be generated based on the identifier of the first satellite carried in the sixth request; or, the second information may be generated based on the identifier of the first satellite carried in the seventh request.

[0398] In a scenario where the Xn extended interface is supported or not supported between the first satellite and the second satellite, in order to ensure the continuity of the PDU session of the first terminal, after receiving the second information, the fourth network function on the ground needs to request the first network function on the first satellite to establish an N4 session for the first terminal. Based on this, in one embodiment, after sending the second information to the first network function on the first satellite through the gateway, the method further includes:

[0399] A second request is sent to the first network function through the gateway; wherein the second request is used to request establishment of an N4 session of the first terminal and carries AN tunnel information.

[0400] Here, the second request can be understood as an N4 session establishment request or a request to establish an N4 session.

[0401] After the N4 session of the first terminal is established, the second network function on the ground needs to notify the eighth network function on the ground that the PDU session connection of the first terminal is switched from the UPF on the second satellite to the UPF on the first satellite. Based on this, in one embodiment, after sending the second request to the first network function through the gateway, the method further includes:

[0402] The seventh information is sent to the eighth network function on the ground, wherein the seventh information indicates that the PDU session connection of the first terminal is switched from the third network function to the first network function.

[0403] In one embodiment, the seventh information includes one or more of the following:

[0404] The connection change type that characterizes the change in intersatellite connection;

[0405] an identifier of the first satellite;

[0406] the address of the first network function;

[0407] The first state represents an uncompleted change of the PDU session connection of the first terminal.

[0408] Here, the eighth network function on the ground includes the PCF and / or a network function having the same function as the PCF. The seventh information may be carried in the connection change notification message. The first state may be described as a connection change situation (in progress).

[0409] In one embodiment, after sending the seventh information to the eighth network function on the ground, the method further includes one or more of the following:

[0410] receiving eighth information sent by the eighth network function, wherein the eighth information indicates confirmation that the PDU session connection of the first terminal can be switched from the third network function to the first network function;

[0411] Sending an eighth request to the third network function through the gateway, where the eighth request is used to request to terminate the N4 session of the first terminal;

[0412] receiving a first response sent by the third network function through the gateway, where the first response indicates that the N4 session of the first terminal has been terminated or not terminated;

[0413] Ninth information is sent to the eighth network function, where the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function.

[0414] Here, in the scenario where the Xn extended interface is supported between the first satellite and the second satellite, after sending the seventh information to the eighth network function on the ground, the eighth information sent by the eighth network function is received. The eighth information can be carried in the connection change notification confirmation message, or the eighth information can be understood as a confirmation message of the connection change notification.

[0415] In a scenario where the Xn extended interface is not supported between the first satellite and the second satellite, after sending the seventh information to the eighth network function on the ground, at least an eighth request is sent to the third network function on the second satellite through the gateway, and the eighth request can be understood as an N4 session termination request; a first response sent by the third network function on the second satellite through the gateway can also be received; when the first response indicates that the N4 session of the first terminal has been terminated, ninth information can also be sent to the eighth network function on the ground, and the ninth information can be carried in a connection change notification message.

[0416] In one embodiment, the ninth information includes one or more of the following:

[0417] The connection change type that characterizes the change in intersatellite connection;

[0418] an identifier of the first satellite;

[0419] the address of the first network function;

[0420] The second state represents that the change of the PDU session connection of the first terminal has been completed.

[0421] The second state may be described as a connection change condition (complete).

[0422] Correspondingly, the embodiment of the present application further provides a switching method, which is applied to the eighth network function on the ground, and the eighth network function on the ground includes PCF and / or a network function having the same function as PCF. Fig.12 As shown, the method includes:

[0423] Step 1201: Receive the seventh information sent by the second network function on the ground.

[0424] The seventh information indicates that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, and the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite.

[0425] Here, in the scenario where the Xn extended interface is supported or not supported between the first satellite and the second satellite, the seventh information sent by the second network function on the ground will be received. In one embodiment, the seventh information includes one or more of the following:

[0426] The connection change type that characterizes the change in intersatellite connection;

[0427] an identifier of the first satellite;

[0428] the address of the first network function;

[0429] The first state represents an uncompleted change of the PDU session connection of the first terminal.

[0430] Step 1202: Send the seventh information to the sixth network function on the ground.

[0431] The sixth network function represents a network function accessed by the multimedia session of the first terminal.

[0432] Here, when the seventh information is received, the address of the first network function on the first satellite is saved; based on the association relationship between the network functions established when the multimedia session is established, the sixth network function accessed by the multimedia session of the first terminal is determined, and the seventh information is sent to the sixth network function. The sixth network function is the P-CSCF or SBC-C where the multimedia session of the first terminal is located, that is, the P-CSCF or SBC-C to which the first terminal is connected.

[0433] In the scenario where the Xn extended interface is supported or not supported between the first satellite and the second satellite, after receiving the seventh information, the sixth network function on the ground instructs the fifth network function on the first satellite to allocate media resources to the first terminal, and notifies the eighth network function on the ground that the PDU session connection of the first terminal can be switched from the third network function on the second satellite to the first network function on the first satellite. Based on this, in one embodiment, after sending the seventh information to the sixth network function on the ground, the method further includes:

[0434] receiving eighth information sent by the sixth network function, wherein the eighth information indicates confirmation that the PDU session connection of the first terminal can be switched from the third network function to the first network function;

[0435] Sending the eighth information to the second network function.

[0436] Here, when the eighth network function on the ground receives the eighth information, it forwards the eighth information to the second network function on the ground. For example, the ground PCF receives the eighth information sent by the P-CSCF of the first terminal and sends the eighth information to the ground SMF. The eighth information can be carried in the confirmation message of the connection change notification message.

[0437] In a scenario where the Xn extended interface is not supported between the first satellite and the second satellite, in one embodiment, after sending the eighth information to the second network function, the method further includes:

[0438] receiving ninth information sent by the second network function, where the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function;

[0439] The ninth information is sent to the sixth network function.

[0440] Here, for example, the ground PCF receives the ninth information sent by the ground SMF, and forwards the ninth information to the P-CSCF of the first terminal.

[0441] In one embodiment, the ninth information includes one or more of the following:

[0442] The connection change type that characterizes the change in intersatellite connection;

[0443] an identifier of the first satellite;

[0444] the address of the first network function;

[0445] The second state represents that the change of the PDU session connection of the first terminal has been completed.

[0446] Correspondingly, the embodiment of the present application further provides a switching method, which is applied to the sixth network function on the ground, and the sixth network function is the P-CSCF or SBC-C where the multimedia session of the first terminal is located, that is, the P-CSCF or SBC-C connected to the first terminal. Fig.13 As shown, the method includes:

[0447] Step 1301: Receive the seventh information sent by the eighth network function on the ground.

[0448] The seventh information indicates that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite, and the sixth network function represents a network function for multimedia session access of the first terminal.

[0449] Here, in a scenario where the Xn extended interface is supported or not supported between the first satellite and the second satellite, the seventh information sent by the eighth network function on the ground is received, for example, the P-CSCF of the first terminal receives the seventh information sent by the ground PCF.

[0450] In order to facilitate the eighth network function on the ground to learn the change of the PDU session connection of the first terminal, in one embodiment, the seventh information includes one or more of the following:

[0451] The connection change type that characterizes the change in intersatellite connection;

[0452] an identifier of the first satellite;

[0453] the address of the first network function;

[0454] The first state represents an uncompleted change of the PDU session connection of the first terminal.

[0455] Step 1302: Send fourth information related to the multimedia session on the first satellite through the gateway, where the fourth information indicates allocation of media resources for the first terminal.

[0456] For example, the P-CSCF of the first terminal sends fourth information to the AGW or SBC-U on the first satellite through the gateway to instruct the AGW or SBC-U on the first satellite to allocate media resources for the multimedia session of the first terminal.

[0457] In a scenario where an Xn extended interface is supported between the first satellite and the second satellite, in one embodiment, after sending, through the gateway, fourth information to a fifth network function related to the multimedia session on the first satellite, the method further includes:

[0458] receiving tenth information sent by the first terminal, where the tenth information is sent by the first terminal after receiving third information sent by the first network device on the first satellite, and the third information and the tenth information indicate that the connection switching between the first terminal and the first satellite is completed;

[0459] An eleventh message is sent to a ninth network function on the ground, wherein the ninth network function represents a network function for multimedia session access of a second terminal communicating with the first terminal, and the eleventh message indicates that the address and port of the multimedia session between the second terminal and the first terminal are modified to the address and port of the fifth network function.

[0460] Here, the ninth network function on the ground includes the P-CSCF and / or SBC-C of the second terminal; when the seventh network function on the second satellite is AGW, the ninth network function on the ground is P-CSCF; when the seventh network function on the second satellite is SBC-U, the ninth network function on the ground is SBC-C. The tenth information can be understood as switching history information.

[0461] In order to facilitate the sixth network function on the ground to learn the switching history of the communication service of the first terminal, in one embodiment, the tenth information includes one or more of the following:

[0462] an identifier of the first satellite;

[0463] an identification of the second satellite;

[0464] A third state, wherein the third state indicates that the connection switching between the first terminal and the first satellite is completed.

[0465] In order to ensure the continuity of the multimedia session of the first terminal, in a scenario where the Xn extended interface is not supported between the first satellite and the second satellite, in one embodiment, after sending the eighth information to the eighth network function, the method further includes:

[0466] receiving ninth information sent by the eighth network function, where the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function;

[0467] An eleventh message is sent to a ninth network function on the ground, wherein the ninth network function represents a network function for multimedia session access of a second terminal communicating with the first terminal, and the eleventh message indicates that the address and port of the multimedia session between the second terminal and the first terminal are modified to the address and port of the fifth network function.

[0468] Here, after receiving the ninth information sent by the eighth network function on the ground, the sixth network function on the ground sends the eleventh information to the ninth network function on the ground through the I / S-CSCF on the ground. For example, the P-CSCF of the first terminal receives the ninth information and sends the eleventh information to the P-CSCF of the second terminal through the I / S-CSCF on the ground; the eleventh information indicates that the address and port of the multimedia session between the second terminal and the first terminal are modified to the address and port of the AGW or SBC-U on the first satellite.

[0469] In actual application, the sixth network function on the ground can send an intra-session INVITE or UPDATE message to the ninth network function on the ground through the ground I / S-CSCF based on the ninth information, and the INVITE or UPDATE message carries the eleventh information. For example, the address and port of the multimedia session in the SDP of the INVITE or UPDATE message are modified to the address and port of the AGW or SBC-U on the first satellite.

[0470] In order to facilitate the eighth network function on the ground to learn the switching history of the communication service of the first terminal, in one embodiment, the ninth information includes one or more of the following:

[0471] The connection change type that characterizes the change in intersatellite connection;

[0472] an identifier of the first satellite;

[0473] the address of the first network function;

[0474] The second state represents that the change of the PDU session connection of the first terminal has been completed.

[0475] In order to ensure the continuity of the multimedia session of the first terminal, in a scenario where the Xn extended interface is not supported between the first satellite and the second satellite, in one embodiment, after sending the eleventh information to the ninth network function on the ground, the method further includes one or more of the following:

[0476] Sending sixth information to a seventh network function related to the multimedia session on the second satellite through the gateway, wherein the sixth information instructs the seventh network function to release media resources of the first terminal;

[0477] sending eleventh information to the first terminal through the gateway and the first network function, wherein the eleventh information indicates that the port and address of the multimedia session of the first terminal are modified to the address and port of the fifth network function;

[0478] The twelfth information is sent to the second network function on the ground through the eighth network function, and the twelfth information indicates confirmation that the multimedia session of the first terminal has been switched from the third network function to the first network function.

[0479] In order to implement the method on the first satellite side of the embodiment of the present application, the embodiment of the present application also provides a switching device, which is arranged on the first satellite. The first satellite is at least deployed with a first network device and a first network function, such as Fig.14 As shown, the device comprises:

[0480] The first receiving unit 1401 is configured to receive first information sent by a second network device on a second satellite to a first network device on a first satellite; the first information is sent before the second network device moves out of the communication range of a first terminal accessing the second network device, and represents synchronization data for switching a communication service of the first terminal from the second satellite to the first satellite;

[0481] The second receiving unit 1402 is used to receive second information sent by a second network function on the ground to the first network function on the first satellite through a gateway, where the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

[0482] In one embodiment, the second receiving unit 1402 is specifically configured to receive first information sent by a second network device on the second satellite to the first network device through a link between the first satellite and the second satellite.

[0483] In one embodiment, the device further comprises:

[0484] a sixth sending unit, configured to send a first request to a fourth network function where the PDU session of the first terminal is located through the gateway when the first terminal switches from the second network device to the first network device; wherein,

[0485] The first request is used to request switching of the N2 path, and carries a switching type representing inter-satellite switching, an identifier of the first satellite, and N2 SM information.

[0486] In one embodiment, the device further comprises:

[0487] The seventh sending unit is used to send the first indication issued by the first network device to the second network device, where the first indication is used to indicate that the first network device has established a connection with the fourth network function where the PDU session of the first terminal is located.

[0488] In one embodiment, the device further comprises:

[0489] The sixth receiving unit is used to receive a second request sent by the second network function to the first network function through the gateway; wherein the second request is used to request the establishment of an N4 session of the first terminal and carries access network AN tunnel information.

[0490] In one embodiment, the device further comprises:

[0491] an eighth sending unit, configured to send third information to the first terminal upon receiving a confirmation message of the first request sent by the fourth network function where the PDU session of the first terminal is located to the first network device through the gateway, wherein the third information indicates that the connection switching between the first terminal and the first satellite is completed.

[0492] In one embodiment, a fifth network function related to multimedia session is further deployed on the first satellite, and the apparatus further includes:

[0493] The seventh receiving unit is used to receive fourth information sent by the sixth network function on the ground to the fifth network function through the gateway station, the sixth network function represents the network function accessed by the multimedia session of the first terminal, and the fourth information indicates the allocation of media resources for the first terminal.

[0494] In one embodiment, the first information includes information about the PDU session of the first terminal, and an identifier and / or an address of a fourth network function where the PDU session of the first terminal is located.

[0495] In one embodiment, the device further comprises one or more of the following:

[0496] An eighth receiving unit, configured to receive a third request sent by a fourth network function where the PDU session of the first terminal is located to the first network device through the gateway;

[0497] a ninth sending unit, configured to send a confirmation message of the third request sent by the first network device to the fourth network function through the gateway;

[0498] A ninth receiving unit is configured to receive a fourth request sent by the second network function to the first network function through the gateway; wherein:

[0499] The third request represents that the first terminal requests to switch from the second network device to the first network device, and the third request carries source to destination transparent container data, CN tunnel information and N3 address information of the first network function; the confirmation message of the third request carries the PDU session information of the first terminal, AN tunnel information and RANN3 address information; the fourth request is used to request to modify the N4 session, carrying AN tunnel information and RAN N3 address information.

[0500] In actual application, the first receiving unit 1401, the second receiving unit 1402, the sixth sending unit, the seventh sending unit, the sixth receiving unit, the eighth sending unit, the seventh receiving unit, the eighth receiving unit, the ninth sending unit and the ninth receiving unit can be implemented by the processor in the switching device combined with the communication interface.

[0501] In order to implement the method on the second satellite side of the embodiment of the present application, the embodiment of the present application also provides a switching device, which is arranged on the second satellite, and the second satellite is at least deployed with a second network device and a third network function, such as Fig.15 As shown, the device comprises:

[0502] The transceiver unit 1501 is used to send first information sent by a second network device on a second satellite to a first network device on a first satellite, or to receive fifth information sent by a fourth network function where a PDU session of the first terminal is located to the second network device through a gateway; wherein,

[0503] The first information is sent before the second network device on the second satellite moves out of the communication range of the first terminal accessing the second network device, and represents synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite;

[0504] The fifth information is sent after the fourth network function establishes a connection with the first network device on the first satellite, indicating that the communication service of the first terminal can be switched from the second satellite to the first satellite.

[0505] In one embodiment, the transceiver unit 1501 is specifically configured to send the first information sent by the second network device to the first network device on the first satellite through a link between the first network device on the first satellite and the second network device on the second satellite.

[0506] In one embodiment, the device further comprises:

[0507] The tenth receiving unit is used to receive a first indication sent by the first network device to the second network device, where the first indication is used to indicate that the first network device has established a connection with a fourth network function where the PDU session of the first terminal is located.

[0508] In one embodiment, the first information includes information about the PDU session of the first terminal, and an identifier and / or an address of a fourth network function where the PDU session of the first terminal is located.

[0509] In one embodiment, the device further comprises:

[0510] A first determining unit, configured to determine a handover preparation timing based on satellite ephemeris data, location information of the first terminal, and location information of the gateway;

[0511] The first selection unit is configured to select the first satellite as a destination satellite for the first terminal before the second network device moves out of the communication range of the first terminal or before the switching preparation timing is reached.

[0512] In one embodiment, the fifth information includes one or more of the following:

[0513] an identifier of the first satellite;

[0514] an identifier of the first network device;

[0515] A second indication, where the second indication is used to indicate that the fourth network function has established a connection with the first network device.

[0516] In one embodiment, the device further comprises:

[0517] A second determining unit, configured to determine a handover preparation timing based on satellite ephemeris data, location information of the first terminal, and location information of the gateway;

[0518] a tenth sending unit, configured to send a fifth request issued by the second network device to the fourth network function through the gateway before the second network device moves out of the communication range of the first terminal or before the switching preparation timing is reached, wherein the fifth request is used to request to switch the communication service of the first terminal from the second satellite to the first satellite.

[0519] In one embodiment, the fifth request carries one or more of the following:

[0520] Synchronous data from the second network device to the first network device;

[0521] an identifier of the first network device;

[0522] Information about the PDU session of the first terminal;

[0523] The identifier and / or address of the fourth network function where the PDU session of the first terminal is located.

[0524] In one embodiment, a seventh network function related to multimedia session is further deployed on the second satellite, and the apparatus further includes:

[0525] An eleventh receiving unit is used to receive sixth information sent by a sixth network function on the ground to the seventh network function through the gateway, wherein the sixth network function represents a network function accessed by the multimedia session of the first terminal, and the sixth information instructs the seventh network function to release media resources of the first terminal.

[0526] In actual application, the transceiver unit 1501, the tenth receiving unit, the tenth sending unit and the eleventh receiving unit can be implemented by a processor in the switching device in combination with a communication interface, and the first determination unit, the second determination unit and the first selection unit can be implemented by a processor in the switching device.

[0527] In order to implement the method of the fourth network function side on the ground of the embodiment of the present application, the embodiment of the present application also provides a switching device, which is arranged on the fourth network function on the ground. The fourth network function on the ground includes AMF and / or a network function having the same function as AMF, such as Fig.16 As shown, the device comprises:

[0528] The first sending unit 1601 is used to send fifth information to the second network device on the second satellite through the gateway when the fourth network function on the ground establishes a connection with the first network device on the first satellite. The fifth information indicates that the communication service of the first terminal accessing the second network device can be switched from the second satellite to the first satellite.

[0529] In one embodiment, the device further comprises:

[0530] The second selection unit is used to select the first satellite as the destination satellite of the first terminal based on the satellite ephemeris data, and establish a connection with the first network device on the first satellite.

[0531] In one embodiment, the fifth information includes one or more of the following:

[0532] an identifier of the first satellite;

[0533] an identifier of the first network device;

[0534] A second indication, where the second indication is used to indicate that the fourth network function has established a connection with the first network device.

[0535] In one embodiment, the device further comprises:

[0536] The twelfth receiving unit is used to receive a fifth request sent by the second network device through the gateway, where the fifth request is used to request to switch the communication service of the first terminal from the second satellite to the first satellite.

[0537] In one embodiment, the fifth request carries one or more of the following:

[0538] Synchronous data from the second network device to the first network device;

[0539] an identifier of the first network device;

[0540] Information about the PDU session of the first terminal;

[0541] The identifier and / or address of the fourth network function where the PDU session of the first terminal is located.

[0542] In one embodiment, the device further comprises:

[0543] An eleventh sending unit is used to send a sixth request to the second network function on the ground, wherein the sixth request is used to request to update the context of the PDU session of the first terminal, carrying the identifier of the first network device, the identifier of the PDU session of the first terminal, the switching type characterizing the inter-satellite switching, and the identifier of the first satellite.

[0544] In one embodiment, the device further comprises:

[0545] A thirteenth receiving unit is used to receive a first request sent by the first network device through the gateway; wherein the first request is sent when the first terminal switches from the second network device to the first network device, and the first request is used to request switching of the N2 path, carrying a switching type characterizing inter-satellite switching, an identifier of the first satellite, and N2 SM information.

[0546] In one embodiment, the device further comprises:

[0547] The twelfth sending unit is used to send a seventh request to the second network function on the ground, wherein the seventh request is used to request to update the context of the PDU session of the first terminal, carrying N2 SM information, a switching type representing the inter-satellite switching, and an identifier of the first satellite.

[0548] In actual application, the first sending unit 1601, the twelfth receiving unit, the eleventh sending unit, the thirteenth receiving unit and the twelfth sending unit can be implemented by a processor in the switching device combined with a communication interface, and the second selection unit can be implemented by a processor in the switching device.

[0549] In order to implement the method on the second network function side of the ground in the embodiment of the present application, the embodiment of the present application also provides a switching device, which is arranged on the second network function on the ground. The second network function on the ground includes SMF and / or a network function having the same function as SMF, such as Fig.17 As shown, the device comprises:

[0550] The third receiving unit 1701 is configured to receive a seventh request sent by a fourth network function on the ground; wherein the seventh request is used to request to update the context of the PDU session of the first terminal, carries N2 SM information, a switching type representing the inter-satellite switching, and an identifier of the first satellite, and the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite;

[0551] The second sending unit 1702 is used to send second information to the first network function on the first satellite through the gateway, where the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

[0552] In one embodiment, the device further comprises:

[0553] a generating unit, configured to generate the second information based on the information carried in the sixth request; or

[0554] Used to generate the second information based on the information carried by the seventh request.

[0555] In one embodiment, the device further comprises:

[0556] The thirteenth sending unit is used to send a second request to the first network function through the gateway; wherein the second request is used to request to establish an N4 session of the first terminal and carries AN tunnel information.

[0557] In one embodiment, the device further comprises:

[0558] The fourteenth sending unit is used to send seventh information to the eighth network function on the ground, and the seventh information indicates that the PDU session connection of the first terminal is switched from the third network function to the first network function.

[0559] In one embodiment, the seventh information includes one or more of the following:

[0560] The connection change type that characterizes the change in intersatellite connection;

[0561] an identifier of the first satellite;

[0562] the address of the first network function;

[0563] The first state represents an uncompleted change of the PDU session connection of the first terminal.

[0564] In one embodiment, the device further comprises one or more of the following:

[0565] A fourteenth receiving unit, configured to receive eighth information sent by the eighth network function, where the eighth information indicates confirmation that the PDU session connection of the first terminal can be switched from the third network function to the first network function;

[0566] A fifteenth sending unit, configured to send an eighth request to the third network function through the gateway, where the eighth request is used to request to terminate the N4 session of the first terminal;

[0567] A fifteenth sending unit is configured to receive a first response sent by the third network function through the gateway, where the first response indicates that the N4 session of the first terminal has been ended or not ended;

[0568] The sixteenth sending unit is used to send ninth information to the eighth network function, where the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function.

[0569] In one embodiment, the ninth information includes one or more of the following:

[0570] The connection change type that characterizes the change in intersatellite connection;

[0571] an identifier of the first satellite;

[0572] the address of the first network function;

[0573] The second state represents that the change of the PDU session connection of the first terminal has been completed.

[0574] In actual application, the third receiving unit 1701, the second sending unit 1702, the thirteenth sending unit, the fourteenth sending unit, the fourteenth receiving unit, the fifteenth sending unit and the sixteenth sending unit can be implemented by the processor in the switching device in combination with the communication interface, and the generating unit can be implemented by the processor in the switching device.

[0575] In order to implement the method of the eighth network function side of the ground of the embodiment of the present application, the embodiment of the present application also provides a switching device, which is arranged on the eighth network function on the ground. The eighth network function on the ground includes PCF and / or a network function having the same function as PCF, such as Fig.18 As shown, the device comprises:

[0576] The fourth receiving unit 1801 is configured to receive a sixth request or a seventh request sent by a fourth network function on the ground; wherein the sixth request and the seventh request are used to request to update the context of the PDU session of the first terminal, and carry at least an identifier of the PDU session of the first terminal, a switching type representing the inter-satellite switching, and an identifier of the first satellite, and the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite;

[0577] The third sending unit 1802 is used to send the seventh information to a sixth network function on the ground, where the sixth network function represents the network function accessed by the multimedia session of the first terminal.

[0578] In one embodiment, the device further comprises:

[0579] A fifteenth receiving unit, configured to receive eighth information sent by the sixth network function, wherein the eighth information indicates confirmation that the PDU session connection of the first terminal can be switched from the third network function to the first network function;

[0580] A seventeenth sending unit is configured to send the eighth information to the second network function.

[0581] In one embodiment, the seventh information includes one or more of the following:

[0582] The connection change type that characterizes the change in intersatellite connection;

[0583] an identifier of the first satellite;

[0584] the address of the first network function;

[0585] The first state represents an uncompleted change of the PDU session connection of the first terminal.

[0586] In one embodiment, the device further comprises:

[0587] A sixteenth receiving unit, configured to receive ninth information sent by the second network function, where the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function;

[0588] An eighteenth sending unit is configured to send the ninth information to the sixth network function.

[0589] In one embodiment, the ninth information includes one or more of the following:

[0590] The connection change type that characterizes the change in intersatellite connection;

[0591] an identifier of the first satellite;

[0592] the address of the first network function;

[0593] The second state represents that the change of the PDU session connection of the first terminal has been completed.

[0594] In actual application, the fourth receiving unit 1801, the third sending unit 1802, the fifteenth receiving unit, the seventeenth sending unit, the sixteenth receiving unit and the eighteenth sending unit can be implemented by a processor in the switching device in combination with a communication interface.

[0595] In order to implement the method on the sixth network function side of the ground of the embodiment of the present application, the embodiment of the present application further provides a switching device, which is arranged on the sixth network function on the ground. The sixth network function on the ground includes the P-CSCF and / or SBC-C of the first terminal, such as Fig.19 As shown, the device comprises:

[0596] The fifth receiving unit 1901 is configured to receive seventh information sent by an eighth network function on the ground, where the seventh information indicates that a PDU session connection of a first terminal is switched from a third network function on a second satellite to a first network function on a first satellite, where the first terminal represents a terminal requesting to switch a communication service from the second satellite to the first satellite, and where the sixth network function represents a network function accessed by a multimedia session of the first terminal;

[0597] The fourth sending unit 1902 is configured to send fourth information related to the multimedia session on the first satellite to a fifth network function through the gateway, where the fourth information indicates allocation of media resources for the first terminal.

[0598] In one embodiment, the device further comprises:

[0599] A nineteenth sending unit is configured to send eighth information to the eighth network function, where the eighth information indicates a confirmation that the PDU session connection of the first terminal can be switched from the third network function to the first network function.

[0600] In one embodiment, the seventh information includes one or more of the following:

[0601] The connection change type that characterizes the change in intersatellite connection;

[0602] an identifier of the first satellite;

[0603] the address of the first network function;

[0604] The first state represents an uncompleted change of the PDU session connection of the first terminal.

[0605] In one embodiment, the device further comprises:

[0606] A seventeenth receiving unit is configured to receive tenth information sent by the first terminal, where the tenth information is sent by the first terminal after receiving third information sent by the first network device on the first satellite, and the third information and the tenth information indicate that the connection switching between the first terminal and the first satellite is completed;

[0607] The twentieth sending unit is used to send the eleventh information to the ninth network function on the ground, wherein the ninth network function represents the network function for multimedia session access of the second terminal communicating with the first terminal, and the eleventh information indicates to modify the address and port of the multimedia session between the second terminal and the first terminal to the address and port of the fifth network function.

[0608] In one embodiment, the tenth information includes one or more of the following:

[0609] an identifier of the first satellite;

[0610] an identification of the second satellite;

[0611] A third state, wherein the third state indicates that the connection switching between the first terminal and the first satellite is completed.

[0612] In one embodiment, the device further comprises:

[0613] An eighteenth receiving unit, configured to receive ninth information sent by the eighth network function, where the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function;

[0614] The twenty-first sending unit is used to send the eleventh information to the ninth network function on the ground, wherein the ninth network function represents the network function for accessing the multimedia session of the second terminal communicating with the first terminal, and the eleventh information indicates to modify the address and port of the multimedia session between the second terminal and the first terminal to the address and port of the fifth network function.

[0615] In one embodiment, the device further comprises one or more of the following:

[0616] A twenty-second sending unit, configured to send sixth information to a seventh network function related to the multimedia session on the second satellite through the gateway, wherein the sixth information instructs the seventh network function to release media resources of the first terminal;

[0617] a twenty-third sending unit, configured to send eleventh information to the first terminal through the gateway and the first network function, wherein the eleventh information indicates that a port and an address of the multimedia session of the first terminal are modified to the address and port of the fifth network function;

[0618] The twenty-fourth sending unit is used to send the twelfth information to the second network function on the ground through the eighth network function, and the twelfth information indicates a confirmation that the multimedia session of the first terminal has been switched from the third network function to the first network function.

[0619] In one embodiment, the ninth information includes one or more of the following:

[0620] The connection change type that characterizes the change in intersatellite connection;

[0621] an identifier of the first satellite;

[0622] the address of the first network function;

[0623] The second state represents that the change of the PDU session connection of the first terminal has been completed.

[0624] In actual application, the fifth receiving unit 1901, the fourth sending unit 1902, the nineteenth sending unit, the seventeenth receiving unit, the twentieth sending unit, the eighteenth receiving unit, the twenty-first sending unit, the twenty-second sending unit, the twenty-third sending unit and the twenty-fourth sending unit can be implemented by the processor in the switching device combined with the communication interface.

[0625] It should be noted that: the switching device provided in the above embodiment only uses the division of the above program modules as an example when switching. In actual applications, the above processing can be assigned to different program modules as needed, that is, the internal structure of the device is divided into different program modules to complete all or part of the processing described above. In addition, the switching device provided in the above embodiment and the switching method embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0626] Based on the hardware implementation of the above program module, and in order to implement the method on the first satellite side of the embodiment of the present application, the embodiment of the present application also provides a first satellite, on which at least a first network device and a first network function are deployed. In actual application, the first network function is UPF, such as Fig. 20 As shown, the first satellite 2000 includes:

[0627] The first communication interface 2001 is capable of exchanging information with other network nodes;

[0628] The first processor 2002 is connected to the first communication interface 2001 to implement information exchange with other network nodes, and is used to execute the method provided by one or more technical solutions of the first satellite side when running a computer program. The computer program is stored in the first memory 2003.

[0629] Specifically, the first communication interface 2001 is used to receive first information sent by a second network device on a second satellite to a first network device on a first satellite, and to receive second information sent by a second network function on the ground to a first network function on the first satellite through a gateway; wherein,

[0630] The first information is sent before the second network device moves out of the communication range of the first terminal connected to the second network device, and represents synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite;

[0631] The second information represents that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is a third network function on the second satellite.

[0632] In one embodiment, the first communication interface 2001 is specifically configured to receive first information sent by a second network device on a second satellite to the first network device through a link between the first satellite and the second satellite.

[0633] In one embodiment, the first communication interface 2001 is further used to send a first request to a fourth network function where the PDU session of the first terminal is located through the gateway when the first terminal switches from the second network device to the first network device; wherein,

[0634] The first request is used to request switching of the N2 path, and carries a switching type representing inter-satellite switching, an identifier of the first satellite, and N2 SM information.

[0635] In one embodiment, the first communication interface 2001 is further used to send a first indication issued by the first network device to the second network device, wherein the first indication is used to indicate that the first network device has established a connection with a fourth network function where the PDU session of the first terminal is located.

[0636] In one embodiment, the first communication interface 2001 is also used to receive a second request sent by the second network function to the first network function through the gateway; wherein the second request is used to request establishment of an N4 session of the first terminal, carrying access network AN tunnel information.

[0637] In one embodiment, the first communication interface 2001 is further used to send third information to the first terminal upon receiving a confirmation message of the first request sent by the fourth network function where the PDU session of the first terminal is located to the first network device through the gateway, wherein the third information indicates that the connection switching between the first terminal and the first satellite is completed.

[0638] In one embodiment, a fifth network function related to multimedia sessions is also deployed on the first satellite, and the first communication interface 2001 is also used to receive fourth information sent by a sixth network function on the ground to the fifth network function through the gateway, the sixth network function represents the network function accessed by the multimedia session of the first terminal, and the fourth information indicates the allocation of media resources for the first terminal.

[0639] In one embodiment, the first information includes information about the PDU session of the first terminal, and an identifier and / or an address of a fourth network function where the PDU session of the first terminal is located.

[0640] In one embodiment, the first communication interface 2001 is further used for one or more of the following:

[0641] receiving a third request sent by a fourth network function where the PDU session of the first terminal is located to the first network device through the gateway;

[0642] Sending a confirmation message of the third request sent by the first network device to the fourth network function through the gateway;

[0643] receiving a fourth request sent by the second network function to the first network function through the gateway; wherein:

[0644] The third request represents that the first terminal requests to switch from the second network device to the first network device, and the third request carries source to destination transparent container data, CN tunnel information and N3 address information of the first network function; the confirmation message of the third request carries the PDU session information of the first terminal, AN tunnel information and RANN3 address information; the fourth request is used to request to modify the N4 session, carrying AN tunnel information and RAN N3 address information.

[0645] It should be noted that the specific processing process of the first processor 2002 and the first communication interface 2001 can be understood by referring to the above method.

[0646] Of course, in actual application, the various components in the first satellite 2000 are coupled together through the bus system 2004. It can be understood that the bus system 2004 is used to realize the connection and communication between these components. In addition to the data bus, the bus system 2004 also includes a power bus, a control bus and a status signal bus. However, for the sake of clarity, Fig. 20 Various buses are labeled as bus system 2004.

[0647] The first memory 2003 in the embodiment of the present application is used to store various types of data to support the operation of the first satellite 2000. Examples of such data include: any computer program used to operate on the first satellite 2000.

[0648] The method disclosed in the above embodiment of the present application can be applied to the first processor 2002, or implemented by the first processor 2002. The first processor 2002 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the first processor 2002. The above-mentioned first processor 2002 may be a general-purpose processor, a digital signal processor (DSP, Digital Signal Processor), or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The first processor 2002 can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor or any conventional processor, etc. In combination with the steps of the method disclosed in the embodiment of the present application, it can be directly embodied as a hardware decoding processor to execute, or it can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium, which is located in the first memory 2003, and the first processor 2002 reads the information in the first memory 2003 and completes the steps of the above method in combination with its hardware.

[0649] In an exemplary embodiment, the first satellite 2000 can be implemented by one or more application specific integrated circuits (ASIC), DSP, programmable logic device (PLD), complex programmable logic device (CPLD), field programmable gate array (FPGA), general processor, controller, microcontroller (MCU), microprocessor, or other electronic components to execute the aforementioned method.

[0650] Based on the hardware implementation of the above program module, and in order to implement the method of the second satellite node side of the embodiment of the present application, the embodiment of the present application also provides a second satellite, on which at least a second network device and a third network function are deployed. In actual application, the third network function is UPF. Fig.21 As shown, the second satellite 2100 includes:

[0651] The second communication interface 2101 is capable of exchanging information with other network nodes;

[0652] The second processor 2102 is connected to the second communication interface 2101 to implement information exchange with other network nodes, and is used to execute the method provided by one or more technical solutions of the second satellite side when running a computer program. The computer program is stored in the second memory 2103.

[0653] Specifically, the second communication interface 2101 is used to send first information sent by a second network device on a second satellite to a first network device on a first satellite, or to receive fifth information sent by a fourth network function where a PDU session of the first terminal is located to the second network device through a gateway; wherein,

[0654] The first information is sent before the second network device on the second satellite moves out of the communication range of the first terminal accessing the second network device, and represents synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite;

[0655] The fifth information is sent after the fourth network function establishes a connection with the first network device on the first satellite, indicating that the communication service of the first terminal can be switched from the second satellite to the first satellite.

[0656] In one embodiment, the second communication interface 2101 is specifically used to send the first information sent by the second network device to the first network device on the first satellite through a link between the first network device on the first satellite and the second network device on the second satellite.

[0657] In one embodiment, the second communication interface 2101 is further used to receive a first indication sent by the first network device to the second network device, wherein the first indication is used to indicate that the first network device has established a connection with a fourth network function where the PDU session of the first terminal is located.

[0658] In one embodiment, the first information includes information about the PDU session of the first terminal, and an identifier and / or an address of a fourth network function where the PDU session of the first terminal is located.

[0659] In one embodiment, the second processor 2102 is used to determine the switching preparation timing based on satellite ephemeris data, the location information of the first terminal and the location information of the gateway; and is used to select the first satellite as the destination satellite of the first terminal before the second network device moves out of the communication range of the first terminal or before reaching the switching preparation timing.

[0660] In one embodiment, the fifth information includes one or more of the following:

[0661] an identifier of the first satellite;

[0662] an identifier of the first network device;

[0663] A second indication, where the second indication is used to indicate that the fourth network function has established a connection with the first network device.

[0664] In one embodiment, the second processor 2102 is further configured to determine a handover preparation timing based on satellite ephemeris data, location information of the first terminal, and location information of the gateway;

[0665] The second communication interface 2101 is also used to send a fifth request issued by the second network device to the fourth network function through the gateway before the second network device moves out of the communication range of the first terminal or before the switching preparation timing is reached, and the fifth request is used to request to switch the communication service of the first terminal from the second satellite to the first satellite.

[0666] In one embodiment, the fifth request carries one or more of the following:

[0667] Synchronous data from the second network device to the first network device;

[0668] an identifier of the first network device;

[0669] Information about the PDU session of the first terminal;

[0670] The identifier and / or address of the fourth network function where the PDU session of the first terminal is located.

[0671] In one embodiment, a seventh network function related to the multimedia session is also deployed on the second satellite, and the second communication interface 2101 is also used to receive sixth information sent by the sixth network function on the ground to the seventh network function through the gateway, the sixth network function represents the network function accessed by the multimedia session of the first terminal, and the sixth information instructs the seventh network function to release the media resources of the first terminal.

[0672] It should be noted that the specific processing process of the second processor 2102 and the second communication interface 2101 can be understood by referring to the above method.

[0673] Of course, in actual application, the various components in the second satellite 2100 are coupled together through the bus system 2104. It can be understood that the bus system 2104 is used to realize the connection and communication between these components. In addition to the data bus, the bus system 2104 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, Fig.21 Various buses are labeled as bus system 2104.

[0674] The second memory 2103 in the embodiment of the present application is used to store various types of data to support the operation of the second satellite 2100. Examples of such data include: any computer program used to operate on the second satellite 2100.

[0675] The method disclosed in the above embodiment of the present application can be applied to the second processor 2102, or implemented by the second processor 2102. The second processor 2102 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the second processor 2102. The above-mentioned second processor 2102 may be a general-purpose processor, DSP, or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The second processor 2102 can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or any conventional processor, etc. In combination with the steps of the method disclosed in the embodiment of the present application, it can be directly embodied as a hardware decoding processor to execute, or it can be executed by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium, which is located in the second memory 2103, and the second processor 2102 reads the information in the second memory 2103 and completes the steps of the above method in combination with its hardware.

[0676] In an exemplary embodiment, the second satellite 2100 may be implemented by one or more ASICs, DSPs, PLDs, CPLDs, FPGAs, general purpose processors, controllers, MCUs, Microprocessors, or other electronic components to perform the aforementioned methods.

[0677] Based on the hardware implementation of the above program module, and in order to implement the method of the fourth network function side of the ground in the embodiment of the present application, the embodiment of the present application also provides a fourth network function on the ground. In actual application, the fourth network function on the ground is AMF. Fig. 22 As shown, the fourth network function 2200 of the ground includes:

[0678] The third communication interface 2201 is capable of exchanging information with other network nodes;

[0679] The third processor 2202 is connected to the third communication interface 2201 to implement information interaction with other network nodes, and is used to execute the method provided by one or more technical solutions of the fourth network function side on the ground when running the computer program. The computer program is stored in the third memory 2203.

[0680] Specifically, the third communication interface 2201 is used to send fifth information to the second network device on the second satellite through the gateway when the fourth network function on the ground establishes a connection with the first network device on the first satellite. The fifth information indicates that the communication service of the first terminal accessing the second network device can be switched from the second satellite to the first satellite.

[0681] In one embodiment, the third processor 2202 is configured to select the first satellite as a destination satellite for the first terminal based on satellite ephemeris data, and establish a connection with the first network device on the first satellite.

[0682] In one embodiment, the fifth information includes one or more of the following:

[0683] an identifier of the first satellite;

[0684] an identifier of the first network device;

[0685] A second indication, where the second indication is used to indicate that the fourth network function has established a connection with the first network device.

[0686] In one embodiment, the third communication interface 2201 is further used to receive a fifth request sent by the second network device through a gateway, where the fifth request is used to request to switch the communication service of the first terminal from the second satellite to the first satellite.

[0687] In one embodiment, the fifth request carries one or more of the following:

[0688] Synchronous data from the second network device to the first network device;

[0689] an identifier of the first network device;

[0690] Information about the PDU session of the first terminal;

[0691] The identifier and / or address of the fourth network function where the PDU session of the first terminal is located.

[0692] In one embodiment, the third communication interface 2201 is also used to send a sixth request to a second network function on the ground, wherein the sixth request is used to request an update of the context of the PDU session of the first terminal, carrying an identifier of the first network device, an identifier of the PDU session of the first terminal, a switching type characterizing inter-satellite switching, and an identifier of the first satellite.

[0693] In one embodiment, the third communication interface 2201 is also used to receive a first request sent by the first network device through the gateway; wherein the first request is sent when the first terminal switches from the second network device to the first network device, and the first request is used to request switching of the N2 path, carrying a switching type characterizing inter-satellite switching, an identifier of the first satellite, and N2 SM information.

[0694] In one embodiment, the third communication interface 2201 is also used to send a seventh request to the second network function on the ground, wherein the seventh request is used to request to update the context of the PDU session of the first terminal, carrying N2 SM information, the switching type representing the inter-satellite switching, and the identifier of the first satellite.

[0695] It should be noted that the specific processing process of the third processor 2202 and the third communication interface 2201 can be understood by referring to the above method.

[0696] Of course, in actual application, the components in the fourth network function 2200 on the ground are coupled together through the bus system 2204. It can be understood that the bus system 2204 is used to realize the connection and communication between these components. In addition to the data bus, the bus system 2204 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, Fig. 22 Various buses are labeled as bus system 2204.

[0697] The third memory 2203 in the embodiment of the present application is used to store various types of data to support the operation of the fourth network function 2200 on the ground. Examples of these data include: any computer program used to operate on the fourth network function 2200 on the ground.

[0698] The method disclosed in the above embodiment of the present application can be applied to the third processor 2202, or implemented by the third processor 2202. The third processor 2202 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by an integrated logic circuit of the hardware in the third processor 2202 or an instruction in the form of software. The above-mentioned third processor 2202 may be a general-purpose processor, a DSP, or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The third processor 2202 can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or any conventional processor, etc. In combination with the steps of the method disclosed in the embodiment of the present application, it can be directly embodied as a hardware decoding processor to execute, or it can be executed by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium, which is located in the third memory 2203, and the third processor 2202 reads the information in the third memory 2203 and completes the steps of the above method in combination with its hardware.

[0699] In an exemplary embodiment, the fourth network function 2200 on the ground can be implemented by one or more ASICs, DSPs, PLDs, CPLDs, FPGAs, general-purpose processors, controllers, MCUs, Microprocessors, or other electronic components to perform the aforementioned method.

[0700] Based on the hardware implementation of the above program module, and in order to implement the method of the second network function side of the ground in the embodiment of the present application, the embodiment of the present application also provides a second network function on the ground. In actual application, the second network function on the ground is SMF. Fig.23 As shown, the second network function 2300 on the ground includes:

[0701] The fourth communication interface 2301 is capable of exchanging information with other network nodes;

[0702] The fourth processor 2302 is connected to the fourth communication interface 2301 to implement information exchange with other network nodes, and is used to execute the method provided by one or more technical solutions of the second network function side on the ground when running the computer program. The computer program is stored in the fourth memory 2303.

[0703] Specifically, the fourth communication interface 2301 is used to receive the seventh request sent by the fourth network function on the ground, and to send the second information to the first network function on the first satellite through the gateway; wherein,

[0704] The seventh request is used to request to update the context of the PDU session of the first terminal, carrying N2 SM information, a switching type representing the inter-satellite switching, and an identifier of the first satellite, where the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite;

[0705] The second information represents that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

[0706] In one embodiment, the fourth processor 2302 is used to generate the second information based on the information carried by the sixth request; or is used to generate the second information based on the information carried by the seventh request.

[0707] In one embodiment, the fourth communication interface 2301 is further used to send a second request to the first network function through the gateway; wherein the second request is used to request to establish an N4 session of the first terminal and carries AN tunnel information.

[0708] In one embodiment, the fourth communication interface 2301 is further used to send seventh information to an eighth network function on the ground, wherein the seventh information indicates that the PDU session connection of the first terminal is switched from the third network function to the first network function.

[0709] In one embodiment, the seventh information includes one or more of the following:

[0710] The connection change type that characterizes the change in intersatellite connection;

[0711] an identifier of the first satellite;

[0712] the address of the first network function;

[0713] The first state represents an uncompleted change of the PDU session connection of the first terminal.

[0714] In one embodiment, the fourth communication interface 2301 is further used for one or more of the following:

[0715] receiving eighth information sent by the eighth network function, wherein the eighth information indicates confirmation that the PDU session connection of the first terminal can be switched from the third network function to the first network function;

[0716] Sending an eighth request to the third network function through the gateway, where the eighth request is used to request to terminate the N4 session of the first terminal;

[0717] receiving a first response sent by the third network function through the gateway, where the first response indicates that the N4 session of the first terminal has been terminated or not terminated;

[0718] Ninth information is sent to the eighth network function, where the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function.

[0719] In one embodiment, the ninth information includes one or more of the following:

[0720] The connection change type that characterizes the change in intersatellite connection;

[0721] an identifier of the first satellite;

[0722] the address of the first network function;

[0723] The second state represents that the change of the PDU session connection of the first terminal has been completed.

[0724] It should be noted that the specific processing process of the fourth processor 2302 and the fourth communication interface 2301 can be understood by referring to the above method.

[0725] Of course, in actual application, the various components in the second network function 2300 on the ground are coupled together through the bus system 2304. It can be understood that the bus system 2304 is used to realize the connection and communication between these components. In addition to the data bus, the bus system 2304 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, Fig.23 Various buses are labeled as bus system 2304.

[0726] The fourth memory 2303 in the embodiment of the present application is used to store various types of data to support the operation of the second network function 2300 on the ground. Examples of such data include: any computer program used to operate on the second network function 2300 on the ground.

[0727] The method disclosed in the above embodiment of the present application can be applied to the fourth processor 2302, or implemented by the fourth processor 2302. The fourth processor 2302 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the fourth processor 2302. The above-mentioned fourth processor 2302 may be a general-purpose processor, DSP, or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The fourth processor 2302 can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or any conventional processor, etc. In combination with the steps of the method disclosed in the embodiment of the present application, it can be directly embodied as a hardware decoding processor to execute, or it can be executed by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium, which is located in the fourth memory 2303, and the fourth processor 2302 reads the information in the fourth memory 2303 and completes the steps of the above method in combination with its hardware.

[0728] In an exemplary embodiment, the ground second network function 2300 can be implemented by one or more ASICs, DSPs, PLDs, CPLDs, FPGAs, general-purpose processors, controllers, MCUs, Microprocessors, or other electronic components to perform the aforementioned method.

[0729] Based on the hardware implementation of the above program module, and in order to implement the method of the eighth network function side of the ground of the embodiment of the present application, the embodiment of the present application also provides an eighth network function on the ground. In actual application, the eighth network function on the ground is PCF. Fig.24 As shown, the eighth network function 2400 of the ground includes:

[0730] The fifth communication interface 2401 is capable of exchanging information with other network nodes;

[0731] The fifth processor 2402 is connected to the fifth communication interface 2401 to implement information interaction with other network nodes, and is used to execute the method provided by one or more technical solutions of the eighth network function side on the ground when running the computer program. The computer program is stored in the fifth memory 2403.

[0732] Specifically, the fifth communication interface 2401 is used to receive the sixth request or the seventh request sent by the fourth network function on the ground, and to send the seventh information to the sixth network function on the ground; wherein,

[0733] The sixth request and the seventh request are used to request updating the context of the PDU session of the first terminal, and carry at least the identifier of the PDU session of the first terminal, the switching type representing the inter-satellite switching, and the identifier of the first satellite. The first terminal represents the terminal requesting to switch the communication service from the second satellite to the first satellite; the sixth network function represents the network function accessed by the multimedia session of the first terminal.

[0734] In one embodiment, the fifth communication interface 2401 is also used to receive the eighth information sent by the sixth network function, and to send the eighth information to the second network function, wherein the eighth information represents confirmation that the PDU session connection of the first terminal can be switched from the third network function to the first network function.

[0735] In one embodiment, the seventh information includes one or more of the following:

[0736] The connection change type that characterizes the change in intersatellite connection;

[0737] an identifier of the first satellite;

[0738] the address of the first network function;

[0739] The first state represents an uncompleted change of the PDU session connection of the first terminal.

[0740] In one embodiment, the fifth communication interface 2401 is also used to receive ninth information sent by the second network function, and to send the ninth information to the sixth network function, wherein the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function.

[0741] In one embodiment, the ninth information includes one or more of the following:

[0742] The connection change type that characterizes the change in intersatellite connection;

[0743] an identifier of the first satellite;

[0744] the address of the first network function;

[0745] The second state represents that the change of the PDU session connection of the first terminal has been completed.

[0746] It should be noted that the specific processing process of the fifth processor 2402 and the fifth communication interface 2401 can be understood by referring to the above method.

[0747] Of course, in actual application, the various components in the eighth network function 2400 on the ground are coupled together through the bus system 2404. It can be understood that the bus system 2404 is used to realize the connection and communication between these components. In addition to the data bus, the bus system 2404 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, Fig.24 Various buses are labeled as bus system 2404.

[0748] The fifth memory 2403 in the embodiment of the present application is used to store various types of data to support the operation of the eighth network function 2400 on the ground. Examples of these data include: any computer program used to operate on the eighth network function 2400 on the ground.

[0749] The method disclosed in the above embodiment of the present application can be applied to the fifth processor 2402, or implemented by the fifth processor 2402. The fifth processor 2402 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by an integrated logic circuit of the hardware in the fifth processor 2402 or an instruction in the form of software. The fifth processor 2402 mentioned above may be a general-purpose processor, a DSP, or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The fifth processor 2402 can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or any conventional processor, etc. In combination with the steps of the method disclosed in the embodiment of the present application, it can be directly embodied as a hardware decoding processor to execute, or it can be executed by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium, which is located in the fifth memory 2403, and the fifth processor 2402 reads the information in the fifth memory 2403 and completes the steps of the above method in combination with its hardware.

[0750] In an exemplary embodiment, the eighth network function 2400 on the ground can be implemented by one or more ASICs, DSPs, PLDs, CPLDs, FPGAs, general-purpose processors, controllers, MCUs, Microprocessors, or other electronic components to perform the aforementioned method.

[0751] Based on the hardware implementation of the above program module, and in order to implement the method of the sixth network function side of the ground in the embodiment of the present application, the embodiment of the present application also provides a sixth network function on the ground. In actual application, the sixth network function on the ground is the P-CSCF or SBC-C of the first terminal. Fig.25 As shown, the sixth network function 2500 of the ground includes:

[0752] The sixth communication interface 2501 is capable of exchanging information with other network nodes;

[0753] The sixth processor 2502 is connected to the sixth communication interface 2501 to implement information exchange with other network nodes, and is used to execute the method provided by one or more technical solutions of the sixth network function side on the ground when running the computer program. The computer program is stored in the sixth memory 2503.

[0754] Specifically, the sixth communication interface 2501 is used to receive the seventh information sent by the eighth network function on the ground, and to send the fourth information related to the fifth network function of the multimedia session on the first satellite through the gateway; wherein,

[0755] The seventh information indicates that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite, the sixth network function represents a network function for multimedia session access of the first terminal; the fourth information indicates allocation of media resources for the first terminal.

[0756] In one embodiment, the sixth communication interface 2501 is further used to send eighth information to the eighth network function, and the eighth information indicates confirmation that the PDU session connection of the first terminal can be switched from the third network function to the first network function.

[0757] In one embodiment, the seventh information includes one or more of the following:

[0758] The connection change type that characterizes the change in intersatellite connection;

[0759] an identifier of the first satellite;

[0760] the address of the first network function;

[0761] The first state represents an uncompleted change of the PDU session connection of the first terminal.

[0762] In one embodiment, the sixth communication interface 2501 is further used to receive the tenth information sent by the first terminal, and to send the eleventh information to the ninth network function on the ground; wherein,

[0763] The tenth information is sent by the first terminal when the first terminal receives the third information sent by the first network device on the first satellite, and the third information and the tenth information indicate that the connection switching between the first terminal and the first satellite is completed;

[0764] The ninth network function represents a network function for multimedia session access of a second terminal communicating with the first terminal, and the eleventh information indicates that the address and port of the multimedia session between the second terminal and the first terminal are modified to the address and port of the fifth network function.

[0765] In one embodiment, the tenth information includes one or more of the following:

[0766] an identifier of the first satellite;

[0767] an identification of the second satellite;

[0768] A third state, wherein the third state indicates that the connection switching between the first terminal and the first satellite is completed.

[0769] In one embodiment, the sixth communication interface 2501 is further used to receive ninth information sent by the eighth network function, and to send eleventh information to the ninth network function on the ground; wherein the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function;

[0770] The ninth network function represents a network function for multimedia session access of a second terminal communicating with the first terminal, and the eleventh information indicates that the address and port of the multimedia session between the second terminal and the first terminal are modified to the address and port of the fifth network function.

[0771] In one embodiment, the sixth communication interface 2501 is further used for one or more of the following:

[0772] Sending sixth information to a seventh network function related to the multimedia session on the second satellite through the gateway, wherein the sixth information instructs the seventh network function to release media resources of the first terminal;

[0773] sending eleventh information to the first terminal through the gateway and the first network function, wherein the eleventh information indicates that the port and address of the multimedia session of the first terminal are modified to the address and port of the fifth network function;

[0774] The twelfth information is sent to the second network function on the ground through the eighth network function, and the twelfth information indicates confirmation that the multimedia session of the first terminal has been switched from the third network function to the first network function.

[0775] In one embodiment, the ninth information includes one or more of the following:

[0776] The connection change type that characterizes the change in intersatellite connection;

[0777] an identifier of the first satellite;

[0778] the address of the first network function;

[0779] The second state represents that the change of the PDU session connection of the first terminal has been completed.

[0780] It should be noted that the specific processing process of the sixth processor 2502 and the sixth communication interface 2501 can be understood by referring to the above method.

[0781] Of course, in actual application, the various components in the sixth network function 2500 on the ground are coupled together through the bus system 2504. It can be understood that the bus system 2504 is used to realize the connection and communication between these components. In addition to the data bus, the bus system 2504 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, Fig.25 Various buses are labeled as bus system 2504.

[0782] The sixth memory 2503 in the embodiment of the present application is used to store various types of data to support the operation of the sixth network function 2500 on the ground. Examples of these data include: any computer program used to operate on the sixth network function 2500 on the ground.

[0783] The method disclosed in the above embodiment of the present application can be applied to the sixth processor 2502, or implemented by the sixth processor 2502. The sixth processor 2502 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the sixth processor 2502. The above-mentioned sixth processor 2502 may be a general-purpose processor, DSP, or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The sixth processor 2502 can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or any conventional processor, etc. In combination with the steps of the method disclosed in the embodiment of the present application, it can be directly embodied as a hardware decoding processor to execute, or it can be executed by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium, which is located in the sixth memory 2503, and the sixth processor 2502 reads the information in the sixth memory 2503 and completes the steps of the above method in combination with its hardware.

[0784] In an exemplary embodiment, the sixth network function 2500 on the ground can be implemented by one or more ASICs, DSPs, PLDs, CPLDs, FPGAs, general-purpose processors, controllers, MCUs, Microprocessors, or other electronic components to perform the aforementioned methods.

[0785] It can be understood that the memory (first memory 2003, second memory 2103, third memory 2203, fourth memory 2303, fifth memory 2403 and sixth memory 2503) of the embodiment of the present application can be a volatile memory or a non-volatile memory, and can also include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a ferromagnetic random access memory (FRAM), a flash memory, a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD-ROM); the magnetic surface memory can be a disk memory or a tape memory. Volatile memory can be random access memory (RAM), which acts as external cache.By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), synchronous static random access memory (SSRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), direct memory bus random access memory (DRRAM). The memory described in the embodiments of the present application is intended to include but is not limited to these and any other suitable types of memory.

[0786] In an exemplary embodiment, the embodiment of the present application further provides a storage medium, namely a computer storage medium, specifically a computer-readable storage medium, for example, including a first memory 2003 storing a computer program, and the computer program can be executed by the first processor 2002 of the first satellite 2000 to complete the steps of the first satellite side method. For another example, a second memory 2103 storing a computer program is included, and the computer program can be executed by the second processor 2102 of the second satellite 2100 to complete the steps of the second satellite side method. For another example, a third memory 2203 storing a computer program is included, and the computer program can be executed by the third processor 2202 of the fourth network function 2200 on the ground to complete the steps of the fourth network function side method on the ground. For another example, a fourth memory 2303 storing a computer program is included, and the computer program can be executed by the fourth processor 2302 of the second network function 2300 on the ground to complete the steps of the second network function side method on the ground. For another example, a fifth memory 2403 for storing a computer program may be executed by a fifth processor 2402 of the eighth network function 2400 on the ground to complete the steps of the eighth network function side method on the ground. For another example, a sixth memory 2503 for storing a computer program may be executed by a sixth processor 2502 of the sixth network function 2500 on the ground to complete the steps of the sixth network function side method on the ground. The computer-readable storage medium may be a memory such as FRAM, ROM, PROM, EPROM, EEPROM, Flash Memory, magnetic surface memory, optical disk, or CD-ROM.

[0787] Exemplarily, an embodiment of the present application further provides a computer program product, including a computer program, which can be executed by the first processor 2002 of the first satellite 2000 to complete the steps of the first satellite side method. The computer program can be executed by the second processor 2102 of the second satellite 2100 to complete the steps of the second satellite side method. For example, including a third memory 2203 storing a computer program, the computer program can be executed by the third processor 2202 of the fourth network function 2200 on the ground to complete the steps of the fourth network function side method on the ground. The computer program can be executed by the fourth processor 2302 of the second network function 2300 on the ground to complete the steps of the second network function side method on the ground. The computer program can be executed by the fifth processor 2402 of the eighth network function 2400 on the ground to complete the steps of the eighth network function side method on the ground. For another example, the sixth memory 2503 for storing computer programs may be executed by the sixth processor 2502 of the sixth network function 2500 on the ground to complete the steps of the aforementioned sixth network function side method on the ground.

[0788] It should be noted that: "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. Multi-items can be two or more items, and a plurality can be two or more. The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "one or more" in this article means any combination of at least two of any one or more of a plurality. For example, including one or more of A, B, and C can mean including any one or at least two or more elements selected from the set consisting of A, B, and C.

[0789] In addition, the technical solutions described in the embodiments of the present application can be combined arbitrarily without conflict.

[0790] The above description is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application.

Claims

1. A switching method, characterized in that: Applied to a first satellite, where at least a first network device and a first network function are deployed on the first satellite, the method includes: receiving first information sent by a second network device on a second satellite to the first network device; the first information is sent before the second network device moves out of the communication range of the first terminal accessing the second network device, and represents synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite; Receive second information sent by a second network function on the ground to the first network function through a gateway, where the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is a third network function on the second satellite.

2. The method according to claim 1, characterized in that The receiving first information sent by a second network device on a second satellite to the first network device comprises: First information sent to the first network device by a second network device on the second satellite is received through a link between the first satellite and the second satellite.

3. The method according to claim 1, characterized in that After receiving the first information sent by the second network device on the second satellite to the first network device, the method further includes: When the first terminal switches from the second network device to the first network device, a first request is sent to a fourth network function where a protocol data unit PDU session of the first terminal is located through the gateway; wherein, The first request is used to request switching of the N2 path, and carries a switching type representing inter-satellite switching, an identifier of the first satellite, and N2 session management SM information.

4. The method according to claim 1, characterized in that Before receiving the first information sent by the second network device on the second satellite to the first network device, the method further includes: A first indication issued by the first network device is sent to the second network device, where the first indication is used to indicate that the first network device has established a connection with a fourth network function where the PDU session of the first terminal is located.

5. The method according to claim 1, characterized in that After receiving the second information sent by the second network function on the ground to the first network function through the gateway, the method further includes: Receive a second request sent by the second network function to the first network function through the gateway; wherein the second request is used to request establishment of an N4 session of the first terminal and carries access network AN tunnel information.

6. The method according to claim 3, characterized in that The method further comprises: Upon receiving a confirmation message of the first request sent by the fourth network function where the PDU session of the first terminal is located to the first network device through the gateway, third information is sent to the first terminal, wherein the third information indicates that the connection switching between the first terminal and the first satellite is completed.

7. The method according to claim 1, characterized in that A fifth network function related to multimedia session is also deployed on the first satellite, and the method further includes: Receive fourth information sent by a sixth network function on the ground to the fifth network function through the gateway, the sixth network function represents a network function accessed by the multimedia session of the first terminal, and the fourth information indicates allocation of media resources for the first terminal.

8. The method according to any one of claims 1 to 7, characterized in that: The first information includes information about the PDU session of the first terminal, and an identifier and / or address of a fourth network function where the PDU session of the first terminal is located.

9. The method according to any one of claims 1 to 7, characterized in that: The method may further include one or more of the following: receiving a third request sent by a fourth network function where the PDU session of the first terminal is located to the first network device through the gateway; Sending a confirmation message of the third request sent by the first network device to the fourth network function through the gateway; receiving a fourth request sent by the second network function to the first network function through the gateway; wherein: The third request represents that the first terminal requests to switch from the second network device to the first network device, and the third request carries source-to-destination transparent container data, core network CN tunnel information, and N3 address information of the first network function; The confirmation message of the third request carries the PDU session information of the first terminal, AN tunnel information and radio access network RAN ​​N3 address information; the fourth request is used to request modification of the N4 session, carrying AN tunnel information and RAN N3 address information.

10. A switching method, characterized in that: Applied to a second satellite, where at least a second network device and a third network function are deployed on the second satellite, the method comprising: Sending first information sent by the second network device to a first network device on a first satellite; wherein the first information is sent before the second network device moves out of the communication range of the first terminal accessing the second network device, and represents synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite; or Receive fifth information sent by the fourth network function where the PDU session of the first terminal is located to the second network device through the gateway; wherein the fifth information is sent after the fourth network function establishes a connection with the first network device on the first satellite, indicating that the communication service of the first terminal can be switched from the second satellite to the first satellite.

11. The method according to claim 10, characterized in that The sending the first information sent by the second network device to the first network device on the first satellite includes: The first information sent by the second network device is sent to the first network device on the first satellite through a link between the first network device on the first satellite and the second network device on the second satellite.

12. The method according to claim 10, characterized in that Before sending the first information sent by the second network device to the first network device on the first satellite, the method further includes: Receive a first indication sent by the first network device to the second network device, where the first indication is used to indicate that the first network device has established a connection with a fourth network function where a PDU session of the first terminal is located.

13. The method according to claim 10, characterized in that The first information includes information about the PDU session of the first terminal, and an identifier and / or address of a fourth network function where the PDU session of the first terminal is located.

14. The method according to any one of claims 10 to 13, characterized in that Before sending the first information sent by the second network device to the first network device on the first satellite, the method further includes: Determining a handover preparation timing based on satellite ephemeris data, location information of the first terminal, and location information of the gateway; Before the second network device moves out of the communication range of the first terminal or before the switching preparation timing is reached, the first satellite is selected as the destination satellite of the first terminal.

15. The method according to claim 10, characterized in that The fifth information includes one or more of the following: an identifier of the first satellite; an identifier of the first network device; A second indication, where the second indication is used to indicate that the fourth network function has established a connection with the first network device.

16. The method according to claim 10, characterized in that After receiving the fifth information sent by the fourth network function where the PDU session of the first terminal is located to the second network device through the gateway, the method further includes: Determining a handover preparation timing based on satellite ephemeris data, location information of the first terminal, and location information of the gateway; Before the second network device moves out of the communication range of the first terminal or before the switching preparation timing is reached, a fifth request issued by the second network device is sent to the fourth network function through the gateway station, and the fifth request is used to request to switch the communication service of the first terminal from the second satellite to the first satellite.

17. The method according to claim 16, characterized in that The fifth request carries one or more of the following: Synchronous data from the second network device to the first network device; an identifier of the first network device; Information about the PDU session of the first terminal; The identifier and / or address of the fourth network function where the PDU session of the first terminal is located.

18. The method according to any one of claims 10, 15 to 16, characterized in that: The second satellite is also deployed with a seventh network function related to the multimedia session. After receiving the fifth information sent by the fourth network function where the PDU session of the first terminal is located through the gateway, the method further includes: Receive sixth information sent by a sixth network function on the ground to the seventh network function through the gateway, the sixth network function representing the network function accessed by the multimedia session of the first terminal, and the sixth information instructing the seventh network function to release the media resources of the first terminal.

19. A switching method, characterized in that: A fourth network function applied to the ground, the method comprising: When the fourth network function establishes a connection with the first network device on the first satellite, fifth information is sent to the second network device on the second satellite through the gateway, and the fifth information indicates that the communication service of the first terminal accessing the second network device can be switched from the second satellite to the first satellite.

20. The method according to claim 19, characterized in that Before sending the fifth information to the second network device on the second satellite through the gateway, the method further includes: Based on satellite ephemeris data, the first satellite is selected as a destination satellite for the first terminal, and a connection is established with the first network device on the first satellite.

21. The method according to claim 19, characterized in that The fifth information includes one or more of the following: an identifier of the first satellite; an identifier of the first network device; A second indication, where the second indication is used to indicate that the fourth network function has established a connection with the first network device.

22. The method according to claim 19, characterized in that After sending the fifth information to the second network device on the second satellite through the gateway, the method further includes: A fifth request is received, which is sent by the second network device through a gateway, where the fifth request is used to request switching of the communication service of the first terminal from the second satellite to the first satellite.

23. The method according to claim 22, characterized in that The fifth request carries one or more of the following: Synchronous data from the second network device to the first network device; an identifier of the first network device; Information about the PDU session of the first terminal; The identifier and / or address of the fourth network function where the PDU session of the first terminal is located.

24. The method according to claim 22, characterized in that After receiving the fifth request sent by the second network device through the gateway, the method further includes: A sixth request is sent to the second network function on the ground, wherein the sixth request is used to request an update of the context of the PDU session of the first terminal, carrying an identifier of the first network device, an identifier of the PDU session of the first terminal, a switching type characterizing inter-satellite switching, and an identifier of the first satellite.

25. The method according to claim 19, characterized in that The method further comprises: Receive a first request sent by the first network device through the gateway; wherein the first request is sent when the first terminal switches from the second network device to the first network device, and the first request is used to request switching of the N2 path, carrying a switching type characterizing inter-satellite switching, an identifier of the first satellite, and N2 SM information.

26. The method according to claim 25, characterized in that After receiving the first request sent by the first network device through the gateway, the method further includes: A seventh request is sent to the second network function on the ground, wherein the seventh request is used to request updating the context of the PDU session of the first terminal, carrying N2 SM information, a switching type representing inter-satellite switching, and an identifier of the first satellite.

27. A switching method, characterized in that: A second network function applied to the ground, the method comprising: receiving a sixth request or a seventh request sent by a fourth network function on the ground; wherein the sixth request and the seventh request are used to request to update the context of the PDU session of the first terminal, and carry at least an identifier of the PDU session of the first terminal, a switching type representing the inter-satellite switching, and an identifier of the first satellite, and the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite; Second information is sent to the first network function on the first satellite through the gateway, where the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

28. The method according to claim 27, characterized in that The method further comprises: generating the second information based on the information carried in the sixth request; or The second information is generated based on the information carried by the seventh request.

29. The method according to claim 27, characterized in that After sending the second information to the first network function on the first satellite through the gateway, the method further includes: A second request is sent to the first network function through the gateway; wherein the second request is used to request establishment of an N4 session of the first terminal and carries AN tunnel information.

30. The method according to claim 29, characterized in that After sending the second request to the first network function through the gateway, the method further includes: The seventh information is sent to the eighth network function on the ground, wherein the seventh information indicates that the PDU session connection of the first terminal is switched from the third network function to the first network function.

31. The method according to claim 30, characterized in that The seventh information includes one or more of the following: The connection change type that characterizes the change in intersatellite connection; an identifier of the first satellite; the address of the first network function; The first state represents an uncompleted change of the PDU session connection of the first terminal.

32. The method according to claim 30, characterized in that After sending the seventh information to the eighth network function on the ground, the method further includes one or more of the following: receiving eighth information sent by the eighth network function, wherein the eighth information indicates confirmation that the PDU session connection of the first terminal can be switched from the third network function to the first network function; Sending an eighth request to the third network function through the gateway, where the eighth request is used to request to terminate the N4 session of the first terminal; receiving a first response sent by the third network function through the gateway, where the first response indicates that the N4 session of the first terminal has been terminated or not terminated; Ninth information is sent to the eighth network function, where the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function.

33. The method according to claim 32, characterized in that The ninth information includes one or more of the following: The connection change type that characterizes the change in intersatellite connection; an identifier of the first satellite; the address of the first network function; The second state represents that the change of the PDU session connection of the first terminal has been completed.

34. A switching method, characterized in that: An eighth network function applied to the ground, the method comprising: receiving seventh information sent by a second network function on the ground, wherein the seventh information indicates that a PDU session connection of a first terminal is switched from a third network function on the second satellite to a first network function on the first satellite, and the first terminal represents a terminal requesting to switch a communication service from the second satellite to the first satellite; The seventh information is sent to a sixth network function on the ground, where the sixth network function represents a network function to which the multimedia session of the first terminal accesses.

35. The method according to claim 34, characterized in that After sending the seventh information to the sixth network function on the ground, the method further includes: receiving eighth information sent by the sixth network function, wherein the eighth information indicates confirmation that the PDU session connection of the first terminal can be switched from the third network function to the first network function; Sending the eighth information to the second network function.

36. The method according to claim 34, characterized in that The seventh information includes one or more of the following: The connection change type that characterizes the change in intersatellite connection; an identifier of the first satellite; the address of the first network function; The first state represents an uncompleted change of the PDU session connection of the first terminal.

37. The method according to claim 35, characterized in that After sending the eighth information to the second network function, the method further includes: receiving ninth information sent by the second network function, where the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function; The ninth information is sent to the sixth network function.

38. The method according to claim 37, characterized in that The ninth information includes one or more of the following: The connection change type that characterizes the change in intersatellite connection; an identifier of the first satellite; the address of the first network function; The second state represents that the change of the PDU session connection of the first terminal has been completed.

39. A switching method, characterized in that: A sixth network function applied to the ground, the method comprising: receiving seventh information sent by an eighth network function on the ground, where the seventh information indicates that a PDU session connection of the first terminal is switched from a third network function on the second satellite to a first network function on the first satellite, where the first terminal represents a terminal requesting to switch a communication service from the second satellite to the first satellite, and where the sixth network function represents a network function accessed by a multimedia session of the first terminal; Fourth information is sent to a fifth network function related to the multimedia session on the first satellite through the gateway, where the fourth information indicates allocation of media resources for the first terminal.

40. The method according to claim 39, characterized in that After sending the fourth information to the fifth network function related to the multimedia session on the first satellite through the gateway, the method further includes: Eighth information is sent to the eighth network function, where the eighth information indicates confirmation that the PDU session connection of the first terminal can be switched from the third network function to the first network function.

41. The method according to claim 39, characterized in that The seventh information includes one or more of the following: The connection change type that characterizes the change in intersatellite connection; an identifier of the first satellite; the address of the first network function; The first state represents an uncompleted change of the PDU session connection of the first terminal.

42. The method according to claim 40, characterized in that After sending the fourth information to the fifth network function related to the multimedia session on the first satellite through the gateway, the method further includes: receiving tenth information sent by the first terminal, where the tenth information is sent by the first terminal after receiving third information sent by the first network device on the first satellite, and the third information and the tenth information indicate that the connection switching between the first terminal and the first satellite is completed; An eleventh message is sent to a ninth network function on the ground, wherein the ninth network function represents a network function for multimedia session access of a second terminal communicating with the first terminal, and the eleventh message indicates that the address and port of the multimedia session between the second terminal and the first terminal are modified to the address and port of the fifth network function.

43. The method according to claim 42, characterized in that The tenth information includes one or more of the following: an identifier of the first satellite; an identification of the second satellite; The third state indicates that the connection switching between the first terminal and the first satellite is completed.

44. The method according to claim 40, characterized in that After sending the eighth information to the eighth network function, the method further includes: receiving ninth information sent by the eighth network function, where the ninth information indicates that the PDU session connection of the first terminal has been switched from the third network function to the first network function; An eleventh message is sent to a ninth network function on the ground, wherein the ninth network function represents a network function for multimedia session access of a second terminal communicating with the first terminal, and the eleventh message indicates that the address and port of the multimedia session between the second terminal and the first terminal are modified to the address and port of the fifth network function.

45. The method according to claim 44, characterized in that After sending the eleventh information to the ninth network function on the ground, the method further includes one or more of the following: Sending sixth information to a seventh network function related to the multimedia session on the second satellite through the gateway, wherein the sixth information instructs the seventh network function to release media resources of the first terminal; sending eleventh information to the first terminal through the gateway and the first network function, wherein the eleventh information indicates that the port and address of the multimedia session of the first terminal are modified to the address and port of the fifth network function; The twelfth information is sent to the second network function on the ground through the eighth network function, and the twelfth information indicates confirmation that the multimedia session of the first terminal has been switched from the third network function to the first network function.

46. ​​The method according to claim 44, characterized in that The ninth information includes one or more of the following: The connection change type that characterizes the change in intersatellite connection; an identifier of the first satellite; the address of the first network function; The second state represents that the change of the PDU session connection of the first terminal has been completed.

47. A communication device, characterized in that: include: A first receiving unit, configured to receive first information sent by a second network device on a second satellite to a first network device on a first satellite; The first information is sent before the second network device moves out of the communication range of the first terminal connected to the second network device, and represents synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite; A second receiving unit is used to receive second information sent by a second network function on the ground to the first network function on the first satellite through a gateway, wherein the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is a third network function on the second satellite.

48. A communication device, characterized in that: include: a transceiver unit, configured to send first information sent by a second network device on a second satellite to a first network device on a first satellite, or to receive fifth information sent by a fourth network function where a PDU session of the first terminal is located to the second network device through a gateway; wherein, The first information is sent before the second network device on the second satellite moves out of the communication range of the first terminal accessing the second network device, and represents synchronization data for switching the communication service of the first terminal from the second satellite to the first satellite; The fifth information is sent after the fourth network function establishes a connection with the first network device on the first satellite, indicating that the communication service of the first terminal can be switched from the second satellite to the first satellite.

49. A communication device, characterized in that: include: The first sending unit is used to send fifth information to the second network device on the second satellite through the gateway when the fourth network function on the ground establishes a connection with the first network device on the first satellite, wherein the fifth information indicates that the communication service of the first terminal accessing the second network device can be switched from the second satellite to the first satellite.

50. A communication device, characterized in that: include: A third receiving unit is configured to receive a seventh request sent by a fourth network function on the ground; wherein the seventh request is used to request to update the context of the PDU session of the first terminal, carries N2 SM information, a switching type representing the inter-satellite switching, and an identifier of the first satellite, and the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite; The second sending unit is used to send second information to the first network function on the first satellite through the gateway, wherein the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

51. A communication device, characterized in that: include: a fourth receiving unit, configured to receive a sixth request or a seventh request sent by a fourth network function on the ground; wherein the sixth request and the seventh request are used to request to update the context of the PDU session of the first terminal, and carry at least an identifier of the PDU session of the first terminal, a switching type representing the inter-satellite switching, and an identifier of the first satellite, and the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite; The third sending unit is used to send the seventh information to a sixth network function on the ground, where the sixth network function represents the network function accessed by the multimedia session of the first terminal.

52. A communication device, characterized in that: include: a fifth receiving unit, configured to receive seventh information sent by an eighth network function on the ground, where the seventh information indicates that a PDU session connection of the first terminal is switched from a third network function on the second satellite to a first network function on the first satellite, where the first terminal represents a terminal requesting to switch a communication service from the second satellite to the first satellite, and where the sixth network function represents a network function accessed by a multimedia session of the first terminal; The fourth sending unit is configured to send fourth information related to the multimedia session on the first satellite to a fifth network function through the gateway, where the fourth information indicates allocation of media resources for the first terminal.

53. A first satellite, characterized in that: The first satellite is at least equipped with a first network device and a first network function, and the first satellite includes: a first processor and a first communication interface; wherein, The first communication interface is used to receive first information sent by a second network device on a second satellite to a first network device on a first satellite, and to receive second information sent by a second network function on the ground to a first network function on the first satellite through a gateway; wherein, The first information is sent before the second network device moves out of the communication range of the first terminal accessing the second network device, indicating that the communication service of the first terminal is switched from the second satellite to the synchronization data of the first satellite; the second information indicates that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

54. A second satellite, characterized in that: The second satellite is at least equipped with a second network device and a third network function, and the second satellite includes: a second processor and a second communication interface; wherein, The second communication interface is used to send first information sent by the second network device on the second satellite to the first network device on the first satellite, or to receive fifth information sent by the fourth network function where the PDU session of the first terminal is located to the second network device through the gateway; Among them, the first information is sent before the second network device on the second satellite moves out of the communication range of the first terminal accessing the second network device, indicating that the communication service of the first terminal is switched from the second satellite to the synchronization data of the first satellite; the fifth information is sent after the fourth network function establishes a connection with the first network device on the first satellite, indicating that the communication service of the first terminal can be switched from the second satellite to the first satellite.

55. A fourth network function on the ground, characterized in that: include: A third processor and a third communication interface; wherein, The third communication interface is used to send fifth information to the second network device on the second satellite through the gateway when the fourth network function establishes a connection with the first network device on the first satellite, and the fifth information indicates that the communication service of the first terminal accessing the second network device can be switched from the second satellite to the first satellite.

56. A second network function on the ground, characterized in that: include: A fourth processor and a fourth communication interface; wherein, The fourth communication interface is used to receive the sixth request or the seventh request sent by the fourth network function on the ground, and to send the second information to the first network function on the first satellite through the gateway; wherein, The sixth request and the seventh request are used to request updating the context of the PDU session of the first terminal, and carry at least the identifier of the PDU session of the first terminal, the switching type representing the inter-satellite switching, and the identifier of the first satellite. The first terminal represents the terminal requesting to switch the communication service from the second satellite to the first satellite; the second information represents that the second network function selects the first network function as the destination network function of the first terminal, and the source network function of the first terminal is the third network function on the second satellite.

57. An eighth network function on the ground, characterized in that: include: A fifth processor and a fifth communication interface; wherein, The fifth communication interface is used to receive the seventh information sent by the second network function on the ground, and to send the seventh information to the sixth network function on the ground; wherein, The seventh information indicates that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, and the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite; the sixth network function represents the network function of the multimedia session access of the first terminal.

58. A sixth network function on the ground, characterized in that: include: A sixth processor and a sixth communication interface; wherein, The sixth communication interface is used to receive seventh information sent by an eighth network function on the ground, and to send fourth information related to a fifth network function of the multimedia session on the first satellite through the gateway; The seventh information indicates that the PDU session connection of the first terminal is switched from the third network function on the second satellite to the first network function on the first satellite, the first terminal represents a terminal requesting to switch the communication service from the second satellite to the first satellite, the sixth network function represents a network function for multimedia session access of the first terminal; and the fourth information indicates allocation of media resources for the first terminal.

59. A first satellite, characterized in that: The method comprises a first processor and a first memory for storing a computer program that can be run on the first processor, wherein the first processor is used to execute the steps of the method according to any one of claims 1 to 9 when running the computer program.

60. A second satellite, characterized in that: The method comprises a second processor and a second memory for storing a computer program that can be run on the second processor, wherein the second processor is used to execute the steps of the method according to any one of claims 10 to 18 when running the computer program.

61. A fourth network function on the ground, characterized in that: The method comprises a third processor and a third memory for storing a computer program that can be run on the third processor, wherein the third processor is used to execute the steps of the method according to any one of claims 19 to 26 when running the computer program.

62. A second network function on the ground, characterized in that: The method comprises a fourth processor and a fourth memory for storing a computer program that can be run on the fourth processor, wherein the fourth processor is used to execute the steps of the method described in any one of claims 27 to 33 when running the computer program.

63. An eighth network function on the ground, characterized in that: The method comprises a fifth processor and a fifth memory for storing a computer program that can be run on the fifth processor, wherein the fifth processor is used to execute the steps of the method described in any one of claims 34 to 38 when running the computer program.

64. A sixth network function on the ground, characterized in that: The method comprises a sixth processor and a sixth memory for storing a computer program that can be run on the sixth processor, wherein the sixth processor is used to execute the steps of the method described in any one of claims 39 to 46 when running the computer program.

65. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it implements the steps of the method described in any one of claims 1 to 9, or implements the steps of the method described in any one of claims 10 to 18, or implements the steps of the method described in any one of claims 19 to 26, or implements the steps of the method described in any one of claims 27 to 33, or implements the steps of the method described in any one of claims 34 to 38, or implements the steps of the method described in any one of claims 39 to 46.

66. A computer program product comprising a computer program, characterized in that The computer program implements the method according to any one of claims 1 to 46 when executed by a processor.

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