Method and apparatus for determining IMS AGW, and storage medium

Abstract

The present disclosure relates to the technical field of wireless communications, and provides a method and apparatus for determining an IMS AGW, and a storage medium, which are applied to a first network function entity. The method comprises: subscribing to a second network function entity for access network information of a terminal; or receiving first indication information sent by the terminal, and triggering a request to the second network function entity for the access network information of the terminal, the first indication information being used for indicating that a service satellite has been changed; receiving the access network information of the terminal sent by the second network function entity, the access network information comprising a service satellite identifier, and the service satellite identifier being an identifier of the replacement service satellite; and on the basis of the service satellite identifier and the deployment modes of IMS AGWs on the satellite, determining a first IMS AGW serving the terminal, the first IMS AGW being used for supporting satellite-based IMS calls of the terminal.

Description

Method, device and storage medium for determining IMS AGW

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202410151681.5, filed on February 2, 2024, entitled “Method, device and storage medium for determining IMS AGW”, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to the field of wireless communication technologies, and in particular to a method, device, and storage medium for determining an IMS AGW. Background Art

[0004] In the 3rd Generation Partnership Project (3GPP) Rel-19 satellite research project, one of the issues that needs to be addressed is how to achieve "terminal-satellite-terminal" (UE-SAT-UE) communication.

[0005] Related technologies have designed methods for deploying 5G base stations (gNodeBs, gNBs), user plane functions (UPFs), and access gateways (AGWs) on satellites to implement UE-SAT-UE communication. However, they do not consider how to implement UE-SAT-UE communication when the terminal's serving satellite changes. Summary of the Invention

[0006] In response to the problems existing in the related art, the embodiments of the present disclosure provide a method, apparatus, and storage medium for determining an IMS AGW, so as to solve the problem of how to achieve UE-SAT-UE communication when the serving satellite of a terminal is changed.

[0007] In a first aspect, an embodiment of the present disclosure provides a method for determining an IMS AGW, which is applied to a first network function entity and includes:

[0008] subscribing to the access network information of the terminal from the second network function entity; or receiving first indication information sent by the terminal, and triggering a request for the access network information of the terminal from the second network function entity based on the first indication information, where the first indication information is used to indicate that a service satellite has been changed;

[0009] receiving access network information of the terminal sent by the second network function entity, where the access network information includes a serving satellite identifier, and the serving satellite identifier is an identifier of the replaced serving satellite;

[0010] A first IMS AGW serving the terminal is determined according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite, where the first IMS AGW is used to support an on-satellite IMS call of the terminal.

[0011] In some embodiments, determining the first IMS AGW serving the terminal according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite includes:

[0012] In a case where the deployment mode is that an IMS AGW is deployed on each satellite, determining the serving satellite of the terminal according to the serving satellite identifier;

[0013] Determine the IMS AGW deployed on the service satellite of the terminal as the first IMS AGW; or

[0014] In a case where the deployment mode is to deploy a public IMS AGW, determining the public IMS AGW corresponding to the serving satellite identifier according to a mapping relationship between the satellite identifier and the public IMS AGW;

[0015] The public IMS AGW corresponding to the serving satellite identifier is determined as the first IMS AGW.

[0016] In some embodiments, the method further comprises:

[0017] The mapping relationship is adjusted according to the ephemeris information of each satellite.

[0018] In some embodiments, after determining the first IMS AGW serving the terminal, the method further includes:

[0019] Sending second indication information to the second network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on the satellite.

[0020] In some embodiments, the method further comprises:

[0021] In a case where the first IMS AGW and the second IMS AGW are different, sending information about media resources allocated on the first IMS AGW to the terminal and a corresponding communication peer terminal of the terminal;

[0022] The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed.

[0023] In some embodiments, the method further comprises:

[0024] Sending a release request message to the second IMS AGW; the release request message is used to request the second IMS AGW to release the allocated media resources.

[0025] In some embodiments, the method further comprises:

[0026] In a case where the first IMS AGW is the same as the second IMS AGW, indication information for indicating that the IMS AGW serving the terminal has not changed is sent to the terminal.

[0027] In a second aspect, an embodiment of the present disclosure provides a method for determining an IMS AGW, which is applied to a second network function entity, including:

[0028] When a first network function entity subscribes to access network information of a terminal, the access network information of the terminal is fed back to the first network function entity, where the access network information includes a serving satellite identifier, where the serving satellite identifier is an identifier of a replaced serving satellite, and where the serving satellite identifier is used to determine a first IMS AGW serving the terminal, where the first IMS AGW is used to support an on-satellite IMS call for the terminal.

[0029] In some embodiments, the method further comprises:

[0030] receiving second indication information sent by the first network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on a satellite;

[0031] Based on the second indication information, determine the UPF serving the terminal.

[0032] In a third aspect, an embodiment of the present disclosure provides a method for determining an IMS AGW, which is applied to a terminal and includes:

[0033] First indication information is sent to a first network function entity, where the first indication information is used to indicate that a service satellite has been replaced and trigger the first network function entity to request access network information from a second network function entity, where the access network information includes a service satellite identifier, where the service satellite identifier is an identifier of the replaced service satellite, and where the service satellite identifier is used to determine a first IMS AGW serving the service, where the first IMS AGW is used to support on-board IMS calls.

[0034] In some embodiments, the method further comprises:

[0035] In a case where the first IMS AGW and the second IMS AGW are different, receiving information about media resources allocated on the first IMS AGW sent by the first network function entity;

[0036] The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed.

[0037] In some embodiments, the method further comprises:

[0038] In a case where the first IMS AGW is the same as the second IMS AGW, indication information sent by the first network function entity and used to indicate that the serving IMS AGW has not been changed is received.

[0039] In a fourth aspect, an embodiment of the present disclosure further provides a first network function entity, including a memory, a transceiver, and a processor:

[0040] A memory for storing a computer program; a transceiver for transmitting and receiving data under the control of the processor; and a processor for reading the computer program in the memory and performing the following operations:

[0041] subscribing to the access network information of the terminal from the second network function entity; or receiving first indication information sent by the terminal, and triggering a request for the access network information of the terminal from the second network function entity based on the first indication information, where the first indication information is used to indicate that a service satellite has been changed;

[0042] receiving access network information of the terminal sent by the second network function entity, where the access network information includes a serving satellite identifier, and the serving satellite identifier is an identifier of the replaced serving satellite;

[0043] A first IMS AGW serving the terminal is determined according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite, where the first IMS AGW is used to support an on-satellite IMS call of the terminal.

[0044] In some embodiments, determining the first IMS AGW serving the terminal according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite includes:

[0045] In a case where the deployment mode is that an IMS AGW is deployed on each satellite, determining the serving satellite of the terminal according to the serving satellite identifier;

[0046] Determine the IMS AGW deployed on the service satellite of the terminal as the first IMS AGW; or

[0047] In a case where the deployment mode is to deploy a public IMS AGW, determining the public IMS AGW corresponding to the serving satellite identifier according to a mapping relationship between the satellite identifier and the public IMS AGW;

[0048] The public IMS AGW corresponding to the serving satellite identifier is determined as the first IMS AGW.

[0049] In some embodiments, the operations further include:

[0050] The mapping relationship is adjusted according to the ephemeris information of each satellite.

[0051] In some embodiments, after determining the first IMS AGW serving the terminal, the method further includes:

[0052] Sending second indication information to the second network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on the satellite.

[0053] In some embodiments, the operations further include:

[0054] In a case where the first IMS AGW and the second IMS AGW are different, sending information about media resources allocated on the first IMS AGW to the terminal and a corresponding communication peer terminal of the terminal;

[0055] The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed.

[0056] In some embodiments, the operations further include:

[0057] Sending a release request message to the second IMS AGW; the release request message is used to request the second IMS AGW to release the allocated media resources.

[0058] In some embodiments, the operations further include:

[0059] In a case where the first IMS AGW is the same as the second IMS AGW, indication information for indicating that the IMS AGW serving the terminal has not changed is sent to the terminal.

[0060] In a fifth aspect, an embodiment of the present disclosure further provides a second network function entity, including a memory, a transceiver, and a processor:

[0061] A memory for storing a computer program; a transceiver for transmitting and receiving data under the control of the processor; and a processor for reading the computer program in the memory and performing the following operations:

[0062] When a first network function entity subscribes to access network information of a terminal, the access network information of the terminal is fed back to the first network function entity, where the access network information includes a serving satellite identifier, where the serving satellite identifier is an identifier of a replaced serving satellite, and where the serving satellite identifier is used to determine a first IMS AGW serving the terminal, where the first IMS AGW is used to support an on-satellite IMS call for the terminal.

[0063] In some embodiments, the operations further include:

[0064] receiving second indication information sent by the first network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on a satellite;

[0065] Based on the second indication information, determine the UPF serving the terminal.

[0066] In a sixth aspect, an embodiment of the present disclosure further provides a terminal, including a memory, a transceiver, and a processor:

[0067] A memory for storing a computer program; a transceiver for transmitting and receiving data under the control of the processor; and a processor for reading the computer program in the memory and performing the following operations:

[0068] First indication information is sent to a first network function entity, where the first indication information is used to indicate that a service satellite has been replaced and trigger the first network function entity to request access network information from a second network function entity, where the access network information includes a service satellite identifier, where the service satellite identifier is an identifier of the replaced service satellite, and where the service satellite identifier is used to determine a first IMS AGW serving the service, where the first IMS AGW is used to support on-board IMS calls.

[0069] In some embodiments, the operations further include:

[0070] In a case where the first IMS AGW and the second IMS AGW are different, receiving information about media resources allocated on the first IMS AGW sent by the first network function entity;

[0071] The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed.

[0072] In some embodiments, the operations further include:

[0073] In a case where the first IMS AGW is the same as the second IMS AGW, indication information sent by the first network function entity and used to indicate that the serving IMS AGW has not been changed is received.

[0074] In a seventh aspect, an embodiment of the present disclosure further provides an apparatus for determining an IMS AGW, including:

[0075] A first processing module is configured to subscribe to the access network information of the terminal from the second network function entity; or receive first indication information sent by the terminal, and trigger a request for the access network information of the terminal from the second network function entity based on the first indication information, where the first indication information is used to indicate that a serving satellite has been changed;

[0076] A first receiving module is configured to receive access network information of the terminal sent by the second network function entity, where the access network information includes a serving satellite identifier, and the serving satellite identifier is an identifier of a replaced serving satellite;

[0077] The first determining module is configured to determine a first IMS AGW serving the terminal according to the serving satellite identifier and a deployment mode of the IMS AGW on the satellite, where the first IMS AGW is configured to support an on-satellite IMS call of the terminal.

[0078] In an eighth aspect, an embodiment of the present disclosure further provides an apparatus for determining an IMS AGW, including:

[0079] A feedback module is configured to, when a first network function entity subscribes to the access network information of the terminal, feedback the access network information of the terminal to the first network function entity, where the access network information includes a serving satellite identifier, where the serving satellite identifier is an identifier of a replaced serving satellite, and where the serving satellite identifier is used to determine a first IMS AGW serving the terminal, where the first IMS AGW is used to support on-board IMS calls for the terminal.

[0080] In a ninth aspect, an embodiment of the present disclosure further provides an apparatus for determining an IMS AGW, including:

[0081] The fifth sending module is used to send first indication information to the first network function entity, where the first indication information is used to indicate that the service satellite has been replaced and trigger the first network function entity to request access network information from the second network function entity. The access network information includes a service satellite identifier, which is an identifier of the replaced service satellite. The service satellite identifier is used to determine the first IMS AGW of the service, and the first IMS AGW is used to support on-board IMS calls.

[0082] In the tenth aspect, an embodiment of the present disclosure further provides a non-transitory readable storage medium, wherein the non-transitory readable storage medium stores a computer program, and the computer program is used to enable the processor to execute the method for determining the IMS AGW as described in the first aspect, the second aspect, or the third aspect above.

[0083] In the eleventh aspect, an embodiment of the present disclosure further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program is used to enable a computer to execute the method for determining the IMS AGW as described in the first aspect, the second aspect, or the third aspect.

[0084] In a twelfth aspect, an embodiment of the present disclosure further provides a communication device, wherein a computer program is stored in the communication device, and the computer program is used to enable the communication device to execute the method for determining the IMS AGW as described in the first aspect, the second aspect, or the third aspect.

[0085] In a thirteenth aspect, an embodiment of the present disclosure further provides a chip product, wherein a computer program is stored in the chip product, and the computer program is used to enable the chip product to execute the method for determining the IMS AGW as described in the first aspect, the second aspect, or the third aspect.

[0086] The method, device, and storage medium for determining an IMS AGW provided by the embodiments of the present disclosure, when the service satellite of a terminal is replaced, subscribe to the access network information of the terminal from a second network function entity, receive the access network information of the terminal sent by the second network function entity, or receive first indication information sent by the terminal to indicate that the service satellite has been replaced, trigger a request for the access network information of the terminal from the second network function entity based on the first indication information, the access network information includes a service satellite identifier of the replaced service satellite, and determine a first IMS AGW serving the terminal based on the service satellite identifier and the deployment method of the IMS AGW on the satellite. The first IMS AGW supports the on-satellite IMS call of the terminal, thereby realizing UE-SAT-UE communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0088] FIG1 is a schematic diagram of one path of terminal-satellite-terminal communication;

[0089] FIG2 is a second schematic diagram of a terminal-satellite-terminal communication path;

[0090] FIG3 is a flow chart of a method for determining an IMS AGW according to an embodiment of the present disclosure;

[0091] FIG4 is a third schematic diagram of a terminal-satellite-terminal communication path;

[0092] FIG5 is a fourth schematic diagram of a terminal-satellite-terminal communication path;

[0093] FIG6 is a second flow chart of a method for determining an IMS AGW provided in an embodiment of the present disclosure;

[0094] FIG7 is a third flow chart of a method for determining an IMS AGW provided in an embodiment of the present disclosure;

[0095] FIG8 is a fourth flow chart of a method for determining an IMS AGW provided in an embodiment of the present disclosure;

[0096] FIG9 is a fifth flow chart of a method for determining an IMS AGW provided in an embodiment of the present disclosure;

[0097] FIG10 is a flowchart of a method for determining an IMS AGW according to an embodiment of the present disclosure;

[0098] FIG11 is a schematic structural diagram of a first network function entity provided in an embodiment of the present disclosure;

[0099] FIG12 is a schematic structural diagram of a second network function entity provided in an embodiment of the present disclosure;

[0100] FIG13 is a schematic structural diagram of a terminal provided in an embodiment of the present disclosure;

[0101] FIG14 is a schematic diagram of a structure of an apparatus for determining an IMS AGW according to an embodiment of the present disclosure;

[0102] FIG15 is a second structural diagram of an apparatus for determining an IMS AGW provided in an embodiment of the present disclosure;

[0103] FIG. 16 is a third structural diagram of the apparatus for determining an IMS AGW provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0104] When a terminal accesses the 5G and IMS networks deployed on the ground via satellite, the data interaction path between the terminal and the network is divided into two sections: one is the path between the terminal and the satellite, and the other is the path from the satellite to the ground network via the feeder link.

[0105] Figure 1 illustrates one path for terminal-satellite-terminal communication. As shown in Figure 1 , the path for transmitting control plane signaling data is: UE1 <-> Satellite 1 <-> Ground Network <-> Satellite 2 <-> UE2; the path for transmitting user plane media data is: UE1 <-> Satellite 1 <-> Ground Network <-> Satellite 2 <-> UE2. Communication between Satellite 1 and the Ground Network, and between the Ground Network and Satellite 2, is achieved via feeder links.

[0106] If user-plane data exchange occurs between UE1 and UE2, one optimization measure to reduce data latency is to exchange user-plane data on the satellite or via inter-satellite links between satellites, rather than through the terrestrial network. The prerequisite for user-plane data exchange on the satellite is that the gNB and UPF must be deployed on the satellite.

[0107] Figure 2 is a second schematic diagram of the terminal-satellite-terminal communication path. As shown in Figure 2, gNB1 and UPF1 are deployed on Satellite 1, and gNB2 and UPF2 are deployed on Satellite 2. The path for transmitting control plane signaling data remains: UE1 <-> Satellite 1 <-> Ground Network <-> Satellite 2 <-> UE2; however, the path for transmitting user plane media data is: UE1 <-> Satellite 1 <-> Satellite 2 <-> UE2. Satellites communicate with each other via inter-satellite links.

[0108] The results of 3GPP Rel-18 research on direct satellite forwarding are summarized in 3GPP TS 23.501 5.43.3. The Rel-18 research is based on three premises: the satellite type is geostationary Earth Orbit (GEO) and the user belongs to a 5G virtual network (VN) group.

[0109] When the gNB and UPF are deployed on a satellite, a method for implementing UE-SAT-UE communication is implemented. That is, when the IMS determines that UE-SAT-UE communication is required, it sends an indication and the IP address of the communication peer to the 5G system. The 5G system implements on-board data forwarding through a dedicated SMF or I / V-SMF.

[0110] The 3GPP Re-18 study premise limited specific application scenarios, specifically requiring users to communicate with each other to belong to a 5G VN group. In real-world applications, especially in call scenarios, the caller and the called party are typically not in the same 5G VN group. Therefore, 3GPP Re-19 will further study UE-SAT-UE communication for IMS calls in non-5G LAN scenarios.

[0111] Since the AGW in the IMS system is deployed on the ground, the prerequisite for forwarding call data on the satellite is that the IMS media data does not pass through the ground-based AGW. This is only applicable to scenarios where the IMS system does not need to perform encoding conversion or monitor call media streams.

[0112] Therefore, the IMS AGW needs to be deployed on the satellite to implement UE-SAT-UE communication. However, the IMS AGW deployed on the satellite does not consider how to implement UE-SAT-UE communication when the terminal's serving satellite changes.

[0113] Therefore, it is necessary to consider how to implement UE-SAT-UE communication when the IMS AGW is deployed on a satellite.

[0114] In response to the above technical problems, the embodiments of the present disclosure provide a method for determining an IMS AGW, so as to solve the problem of how to achieve UE-SAT-UE communication when the serving satellite of a terminal is changed.

[0115] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure and not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0116] FIG3 is a flow chart of a method for determining an IMS AGW provided by an embodiment of the present disclosure. As shown in FIG3 , an embodiment of the present disclosure provides a method for determining an IMS AGW, the execution subject of which may be a first network function entity, such as a Proxy-Call Session Control Function (P-CSCF) network element. The method includes:

[0117] Step 310: Subscribe to the access network information of the terminal from the second network function entity; or, receive first indication information sent by the terminal, and based on the first indication information, trigger a request for the access network information of the terminal from the second network function entity, where the first indication information is used to indicate a change in the serving satellite.

[0118] Step 320: Receive the access network information of the terminal sent by the second network function entity. The access network information includes a serving satellite identifier, which is an identifier of the replaced serving satellite.

[0119] Step 330: Determine a first IMS AGW serving the terminal according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite. The first IMS AGW is used to support the on-satellite IMS call of the terminal.

[0120] Specifically, the second network function entity may include: a Policy Control Function (PCF) network element and a Session Management Function (SMF) network element, etc. The terminal may be a calling terminal or a called terminal.

[0121] After a terminal connects to a call, during the call, the terminal's serving satellite may change due to movement of the terminal or the satellite. This change in serving satellite may result in a change in the IMS AGW serving the terminal. The first network function entity needs to be informed of the change in serving satellite so that it can subsequently determine the IMS AGW serving the terminal.

[0122] The information that the first network function entity learns that the service satellite of the terminal has been changed can be fed back to the first network function entity by the second network function entity (method one), or can be based on the first indication information sent by the terminal to the first network function entity (method two).

[0123] For method 1, after the IMS call is established, the P-CSCF network element subscribes to the terminal's access network information from the PCF network element. That is, once the terminal's access network information changes, the PCF network element feeds back the changed terminal's access network information to the P-CSCF network element. The PCF network element subscribes to the terminal's access network information from the SMF network element. That is, once the terminal's access network information changes, the SMF network element feeds back the changed terminal's access network information to the PCF network element.

[0124] If the serving satellite changes, the P-CSCF network element receives the terminal's access network information from the PCF network element. This access network information includes the serving satellite identifier, which is the identifier of the changed serving satellite. The P-CSCF network element can use this terminal's access network information to learn about the change in the terminal's serving satellite.

[0125] In the second method, when the serving satellite changes, the terminal sends first indication information to the P-CSCF network element, indicating that the serving satellite has changed. Specifically, the terminal sends a SIP Re-Invite message or a SIP Update message to the P-CSCF network element, carrying the first indication information indicating that the serving satellite has changed.

[0126] After receiving the first indication message from the terminal indicating a change in the serving satellite, the P-CSCF network element triggers a request from the PCF network element for the terminal's access network information. The PCF network element then requests the terminal's access network information from the SMF network element. The SMF network element then feeds back the terminal's access network information to the PCF network element, which in turn feeds back the terminal's access network information to the P-CSCF network element. The access network information includes the serving satellite identifier; the serving satellite identifier is the identifier of the replaced serving satellite.

[0127] The IMS AGW can be deployed on satellites alongside the gNB and UPF, with an IMS AGW deployed on each satellite. Figure 4 shows the third schematic diagram of the terminal-satellite-terminal communication path. As shown in Figure 4, gNB1, UPF1, and IMS AGW1 are deployed on Satellite 1, while gNB2, UPF2, and IMS AGW2 are deployed on Satellite 2. The path for transmitting control plane signaling data remains: UE1 <-> Satellite 1 <-> Terrestrial Network <-> Satellite 2 <-> UE2; the path for transmitting user plane media data is: UE1 <-> Satellite 1 <-> Satellite 2 <-> UE2.

[0128] The deployment method of IMS AGW on satellite can also be to deploy IMS AGW only on specific satellites as public IMS AGW. When IMS AGW is not deployed on the terminal's service satellite, public IMS AGW is selected as the access gateway for the service terminal. Figure 5 is the fourth path diagram of terminal-satellite-terminal communication. As shown in Figure 5, gNB1 and UPF1 are deployed on satellite 1, gNB2 and UPF2 are deployed on satellite 2, and IMS AGW is deployed on other satellites as public AGW. The path for transmitting control plane signaling data is still: UE1<->Satellite 1<->Ground network<->Satellite 2<->UE2; but the path for transmitting user plane media data is: UE1<->Satellite 1<->Public IMS AGW<->Satellite 2<->UE2.

[0129] The first network function entity first determines the deployment mode of the IMS AGW on the satellite, and then determines the first IMS AGW serving the terminal based on the serving satellite identifier included in the access network information.

[0130] The first IMS AGW serves as the IMS AGW of the terminal and provides support for the terminal's on-satellite IMS calls. For example, the first IMS AGW is responsible for forwarding the IMS call data flow between terminals, thereby realizing UE-SAT-UE communication, that is, realizing the terminal's on-satellite IMS calls. The method for determining the IMS AGW provided in the embodiment of the present disclosure, when the terminal's serving satellite is changed, subscribes to the terminal's access network information from a second network function entity, receives the terminal's access network information sent by the second network function entity, or receives first indication information sent by the terminal to indicate that the serving satellite has been changed, triggers a request for the terminal's access network information from the second network function entity based on the first indication information, the access network information includes the service satellite identifier of the replaced service satellite, and determines the first IMS AGW serving the terminal based on the service satellite identifier and the deployment method of the IMS AGW on the satellite. The first IMS AGW supports the terminal's on-satellite IMS calls, thereby realizing UE-SAT-UE communication.

[0131] In some embodiments, determining a first IMS AGW serving a terminal according to a serving satellite identifier and a deployment mode of the IMS AGW on the satellite includes:

[0132] In the case where an IMS AGW is deployed on each satellite, the serving satellite of the terminal is determined according to the serving satellite identifier;

[0133] Determine the IMS AGW deployed on the terminal's service satellite as the first IMS AGW; or

[0134] In the case where the deployment mode is to deploy a public IMS AGW, determining the public IMS AGW corresponding to the serving satellite identifier according to the mapping relationship between the satellite identifier and the public IMS AGW;

[0135] The public IMS AGW corresponding to the serving satellite identifier is determined as the first IMS AGW.

[0136] Specifically, when the deployment mode is that an IMS AGW is deployed on each satellite, one satellite corresponds to one IMS AGW. The first network function entity first determines the service satellite of the terminal according to the service satellite identifier, and then determines the IMS AGW deployed on the service satellite of the terminal as the first IMS AGW serving the terminal.

[0137] For example, according to the serving satellite identifier, it is determined that the serving satellite of the terminal is SAT1, and the IMS AGW1 deployed on the serving satellite SAT1 is used as the first IMS AGW serving the terminal.

[0138] When the deployment mode is to deploy a public IMS AGW, the first network function entity first determines the public IMS AGW corresponding to the serving satellite identifier based on the many-to-one mapping relationship between the satellite identifier and the public IMS AGW, and then determines the public IMS AGW corresponding to the serving satellite identifier as the first IMS AGW serving the terminal.

[0139] In some embodiments, multiple satellites correspond to one public IMS AGW. The first network function entity first determines the serving satellite of the terminal according to the serving satellite identifier, then determines the public IMS AGW corresponding to the serving satellite according to a many-to-one mapping relationship between the satellite and the public IMS AGW, and finally determines the public IMS AGW corresponding to the serving satellite as the first IMS AGW serving the terminal.

[0140] The method for determining an IMS AGW provided by the embodiment of the present disclosure is used to determine the IMS AGW serving a terminal under different IMS AGW deployment modes.

[0141] In some embodiments, the method for determining the IMS AGW provided by the present disclosure further includes:

[0142] The mapping relationship is adjusted according to the ephemeris information of each satellite.

[0143] Specifically, due to the movement of satellites, the distance relationship between satellites will change, so the mapping relationship between satellite identifiers and public IMS AGWs needs to be adjusted.

[0144] The first network function entity dynamically adjusts the mapping relationship between the satellite identifier and the public IMS AGW according to the ephemeris information of each satellite, so that the public IMS AGW determined to be the optimal public IMS AGW is subsequently determined according to the adjusted mapping relationship between the satellite identifier and the public IMS AGW.

[0145] In some embodiments, after determining the first IMS AGW serving the terminal, the method further includes:

[0146] Sending second indication information to the second network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on the satellite.

[0147] Specifically, after determining the first IMS AGW serving the terminal, the P-CSCF network element sends a dedicated resource establishment request to the PCF network element, the request carrying second indication information. The PCF network element then sends a dedicated resource establishment request to the SMF network element, the request carrying IMS AGW indication information. The second indication information indicates that the IMS AGW serving the terminal is the first IMS AGW deployed on the satellite. The second indication information indicates that the IMS AGW deployed on the satellite is selected and specifies which IMS AGW is selected.

[0148] After receiving the IMS AGW indication information, if the IMS AGW deployment method is to deploy an IMS AGW on each satellite, the service satellite of the terminal is the same satellite as the satellite where the first IMS AGW is located. The SMF network element will use the UPF deployed together with the first IMS AGW as the UPF serving the terminal, that is, the SMF network element inserts the UPF as the diversion UPF for the terminal call media stream.

[0149] If the IMS AGW deployment method is to deploy a public IMS AGW, the service satellite of the terminal is not the same satellite as the satellite where the first IMS AGW is located, and there is no UPF deployed on the satellite where the first IMS AGW is located. The SMF network element uses the UPF deployed on the terminal's service satellite as the UPF serving the terminal, that is, the SMF network element inserts the UPF as a diversion UPF for the terminal call media stream.

[0150] In the method for determining the IMS AGW provided by the embodiment of the present disclosure, the first network function entity sends second indication information to the second network function entity so that the second network function entity determines the UPF of the service terminal, which is further conducive to realizing UE-SAT-UE communication.

[0151] In some embodiments, the method for determining the IMS AGW provided by the present disclosure further includes:

[0152] In the case where the first IMS AGW and the second IMS AGW are different, information about the media resources allocated on the first IMS AGW is sent to the terminal and the communication peer terminal of the terminal;

[0153] The second IMS AGW is an IMS AGW that is determined to serve the terminal before the serving satellite of the terminal is changed.

[0154] Specifically, if the second IMS AGW is different from the first IMS AGW, it indicates that the IMS AGW serving the terminal has been replaced, and the user plane media path needs to be updated. Information about the media resources allocated on the first IMS AGW needs to be sent to the terminal and its corresponding communication peer terminal. The media resources allocated on the IMS AGW are used to transmit call data streams between terminals. The media resource information includes session identifiers, connection information such as IP and port numbers, and media information such as codecs. The specific process is as follows:

[0155] When the first network function entity subscribes to the access network information of the terminal from the second network function entity (method one), the P-CSCF network element sends a SIP Re-Invite message or a SIP Update message to the communication peer terminal via the I / S-CSCF network element, and the message carries information about the network-side media resources allocated on the first IMS AGW; the P-CSCF network element sends a SIP Re-Invite message or a SIP Update message to the terminal, and the message carries information about the access-side media resources allocated on the first IMS AGW.

[0156] In the case where the first network function entity receives the first indication information sent by the terminal to indicate a change in the service satellite (method two), since the terminal sends the first indication information through a SIP Re-Invite message or a SIP Update message, the P-CSCF network element returns a SIP 200 OK message to the terminal, and the message carries information about the access side media resources allocated on the first IMS AGW, so that the subsequent terminal can directly send user-plane media data to the first IMS AGW; the P-CSCF network element sends the SIP Re-Invite message or SIP Update message to the communication counterpart terminal via the I / S-CSCF network element, and the message carries information about the network side media resources allocated on the first IMS AGW.

[0157] The method for determining an IMS AGW provided by the embodiment of the present disclosure further facilitates UE-SAT-UE communication by sending information about media resources allocated on the first IMS AGW to the terminal and the corresponding communication peer terminal when the second IMS AGW is different from the first IMS AGW.

[0158] In some embodiments, the method for determining the IMS AGW provided by the present disclosure further includes:

[0159] Send a release request message to the second IMS AGW; the release request message is used to request the second IMS AGW to release the allocated media resources.

[0160] Specifically, since the first IMS AGW currently serves the terminal, the first network function entity may send a release request message to the second IMS AGW to request the second IMS AGW to release the allocated media resources to save media resources.

[0161] In some embodiments, the method for determining the IMS AGW provided by the present disclosure further includes:

[0162] In a case where the first IMS AGW and the second IMS AGW are the same, indication information for indicating that the IMS AGW serving the terminal has not been changed is sent to the terminal.

[0163] Specifically, when the second IMS AGW is the same as the first IMS AGW, it indicates that the serving satellite has changed, but the IMS AGW serving the terminal has not changed. This situation occurs when the IMS AGW is deployed in a public IMS AGW manner.

[0164] The first network function entity sends indication information to the terminal indicating that the IMS AGW serving the terminal has not been changed. For example, the P-CSCF network element directly replies to the terminal with a SIP 200 OK message to indicate that the IMS AGW serving the terminal has not been changed.

[0165] In the method for determining the IMS AGW provided by the embodiment of the present disclosure, when the second IMS AGW is the same as the first IMS AGW, the first network function entity sends indication information to the terminal for indicating that the IMS AGW serving the terminal has not changed, so that the terminal is informed that the IMS AGW serving the terminal has not changed, which is further conducive to achieving UE-SAT-UE communication.

[0166] FIG6 is a second flow chart of a method for determining an IMS AGW provided by an embodiment of the present disclosure. As shown in FIG6 , an embodiment of the present disclosure provides a method for determining an IMS AGW, the execution subject of which may be a second network function entity. The method includes:

[0167] In step 610, when the first network function entity subscribes to the access network information of the terminal, the access network information of the terminal is fed back to the first network function entity. The access network information includes a serving satellite identifier, which is an identifier of the replaced serving satellite. The serving satellite identifier is used to determine the first IMS AGW serving the terminal. The first IMS AGW is used to support on-satellite IMS calls of the terminal.

[0168] Specifically, the second network function entity may include: a Policy Control Function (PCF) network element and a Session Management Function (SMF) network element, etc. The terminal may be a calling terminal or a called terminal.

[0169] After a terminal connects to a call, during the call, the terminal's serving satellite may change due to movement of the terminal or the satellite. This change in serving satellite may result in a change in the IMS AGW serving the terminal. The first network function entity needs to be informed of the change in serving satellite so that it can subsequently determine the IMS AGW serving the terminal.

[0170] The second network function entity may feed back information about the change of the terminal's service satellite to the first network function entity through the terminal's access network information, specifically as follows:

[0171] After the IMS call is established, the P-CSCF network element subscribes to the terminal's access network information from the PCF network element. That is, once the terminal's access network information changes, the PCF network element feeds back the changed terminal's access network information to the P-CSCF network element. The PCF network element subscribes to the terminal's access network information from the SMF network element. That is, once the terminal's access network information changes, the SMF network element feeds back the changed terminal's access network information to the PCF network element.

[0172] When the serving satellite changes, the SMF network element feeds back the terminal's access network information to the PCF network element, which in turn feeds back the terminal's access network information to the P-CSCF network element. The access network information includes the serving satellite identifier, which is the identifier of the replaced serving satellite. The first network function entity can learn that the terminal's serving satellite has changed based on the terminal's access network information.

[0173] The IMS AGW can be deployed on satellites together with the gNB and UPF, with an IMS AGW deployed on each satellite. Alternatively, the IMS AGW can be deployed only on specific satellites as a public IMS AGW.

[0174] The first network function entity first determines the deployment mode of the IMS AGW on the satellite, and then determines the first IMS AGW serving the terminal based on the serving satellite identifier included in the access network information.

[0175] The first IMS AGW serves as the IMS AGW of the terminal and provides support for the terminal's on-satellite IMS calls. For example, the first IMS AGW is responsible for forwarding the IMS call data flow between terminals, thereby realizing UE-SAT-UE communication, that is, realizing the terminal's on-satellite IMS calls.

[0176] In a method for determining an IMS AGW provided by an embodiment of the present disclosure, when a first network function entity subscribes to access network information of a terminal, after the serving satellite of the terminal is changed, a second network function entity feeds back the access network information of the terminal to the first network function entity so that the first network function entity can determine the serving satellite identifier of the replaced serving satellite; based on the serving satellite identifier and the deployment method of the IMS AGW on the satellite, a first IMS AGW serving the terminal is determined, and the first IMS AGW is used to support on-satellite IMS calls of the terminal, thereby realizing UE-SAT-UE communication.

[0177] In some embodiments, the method for determining the IMS AGW provided by the present disclosure further includes:

[0178] receiving second indication information sent by the first network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on the satellite;

[0179] Based on the second indication information, the UPF of the service terminal is determined.

[0180] Specifically, the PCF network element receives a dedicated resource establishment request from the P-CSCF network element, the request carrying IMS AGW indication information; and the PCF network element sends a dedicated resource establishment request to the SMF network element, the request carrying second indication information. The second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on the satellite. The IMS AGW indication information indicates that the IMS AGW deployed on the satellite is selected and specifies which IMS AGW is selected.

[0181] After receiving the second indication information, if the IMS AGW deployment method is to deploy an IMS AGW on each satellite, the service satellite of the terminal is the same satellite as the satellite where the first IMS AGW is located, and the SMF network element will use the UPF deployed with the first IMS AGW as the UPF serving the terminal, that is, the SMF network element inserts the UPF as a diversion UPF for the terminal call media stream.

[0182] If the IMS AGW deployment method is to deploy a public IMS AGW, the service satellite of the terminal is not the same satellite as the satellite where the first IMS AGW is located, and there is no UPF deployed on the satellite where the first IMS AGW is located. The SMF network element uses the UPF deployed on the terminal's service satellite as the UPF serving the terminal, that is, the SMF network element inserts the UPF as a diversion UPF for the terminal call media stream.

[0183] The method for determining the IMS AGW provided by the embodiment of the present disclosure determines the UPF of the service terminal by receiving the second indication information sent by the first network function entity, which is further conducive to realizing UE-SAT-UE communication.

[0184] FIG7 is a third flow chart of a method for determining an IMS AGW provided by an embodiment of the present disclosure. As shown in FIG7 , an embodiment of the present disclosure provides a method for determining an IMS AGW, the execution subject of which may be a terminal. The method includes:

[0185] Step 710: Send first indication information to the first network function entity. The first indication information is used to indicate that the serving satellite has been replaced and trigger the first network function entity to request access network information from the second network function entity. The access network information includes a serving satellite identifier. The serving satellite identifier is the identifier of the replaced serving satellite. The serving satellite identifier is used to determine the first IMS AGW of the service. The first IMS AGW is used to support on-board IMS calls.

[0186] Specifically, the second network function entity may include: a Policy Control Function (PCF) network element and a Session Management Function (SMF) network element, etc. The terminal may be a calling terminal or a called terminal.

[0187] After a terminal connects to a call, during the call, the terminal's serving satellite may change due to movement of the terminal or the satellite. This change in serving satellite may result in a change in the IMS AGW serving the terminal. The first network function entity needs to be informed of the change in serving satellite so that it can subsequently determine the IMS AGW serving the terminal.

[0188] The terminal may send indication information to the first network function entity to notify the first network function entity that the service satellite has been changed, as follows:

[0189] When the serving satellite changes, the terminal sends first indication information to the P-CSCF network element, indicating that the serving satellite has changed. Specifically, the terminal may send a SIP Re-Invite message or a SIP Update message to the P-CSCF network element, carrying the first indication information indicating that the serving satellite has changed.

[0190] After receiving the first indication message from the terminal indicating a change in the serving satellite, the P-CSCF network element is triggered to request the terminal's access network information from the PCF network element, which in turn requests the terminal's access network information from the SMF network element. The SMF network element then feeds back the terminal's access network information to the PCF network element, which in turn feeds back the terminal's access network information to the P-CSCF network element. The access network information includes the serving satellite identifier; the serving satellite identifier is the identifier of the replaced serving satellite.

[0191] The IMS AGW can be deployed on satellites together with the gNB and UPF, with an IMS AGW deployed on each satellite. Alternatively, the IMS AGW can be deployed only on specific satellites as a public IMS AGW.

[0192] The first network function entity first determines the deployment mode of the IMS AGW on the satellite, and then determines the first IMS AGW serving the terminal based on the serving satellite identifier included in the access network information.

[0193] The first IMS AGW serves as the IMS AGW of the terminal and provides support for the terminal's on-satellite IMS calls. For example, the first IMS AGW is responsible for forwarding the IMS call data flow between terminals, thereby realizing UE-SAT-UE communication, that is, realizing the terminal's on-satellite IMS calls.

[0194] The method for determining an IMS AGW provided by an embodiment of the present disclosure sends first indication information for indicating that a service satellite has been replaced to a first network function entity, triggering the first network function entity to request a second network function entity for access network information of a terminal, so that the first network function entity can determine the service satellite identifier of the replaced service satellite; based on the service satellite identifier and the deployment method of the IMS AGW on the satellite, a first IMS AGW serving the terminal is determined, and the first IMS AGW is used to support on-satellite IMS calls of the terminal, thereby realizing UE-SAT-UE communication.

[0195] In some embodiments, the method for determining the IMS AGW provided by the present disclosure further includes:

[0196] In a case where the first IMS AGW and the second IMS AGW are different, receiving information about media resources allocated on the first IMS AGW sent by the first network function entity;

[0197] The second IMS AGW is an IMS AGW that is determined to serve the terminal before the serving satellite of the terminal is changed.

[0198] Specifically, if the second IMS AGW is different from the first IMS AGW, it indicates that the IMS AGW serving the terminal has been replaced, and the user plane media path needs to be updated. The terminal and the communicating peer terminal need to obtain information about the media resources allocated by the first IMS AGW. The media resources allocated by the IMS AGW are used to transmit the call data stream between terminals. The media resource information includes session identifiers, connection information such as IP and port, and media information such as codecs. The specific process is as follows:

[0199] When the first network function entity subscribes to the terminal's access network information from the second network function entity (method one), the communication peer terminal receives a SIP Re-Invite message or a SIP Update message sent by the P-CSCF network element via the I / S-CSCF network element, where the message carries the media resource information on the network side of the first IMS AGW; the terminal receives a SIP Re-Invite message or a SIP Update message sent by the P-CSCF network element, where the message carries the media resource information on the access side of the first IMS AGW.

[0200] In the case where the first network function entity receives the indication information sent by the terminal to indicate a change in the service satellite (method two), since the terminal sends the indication information through a SIP Re-Invite message or a SIP Update message, the terminal receives the SIP 200 OK message returned by the P-CSCF network element, and the message carries the media resource information of the access side of the first IMS AGW, so that the terminal can subsequently directly send the user-plane media data to the first IMS AGW; the communication counterpart terminal receives the SIP Re-Invite message or SIP Update message sent by the P-CSCF network element via the I / S-CSCF network element, and the message carries the media resource information of the network side of the first IMS AGW.

[0201] The method for determining the IMS AGW provided by the embodiment of the present disclosure further facilitates UE-SAT-UE communication by receiving the media resource information of the first IMS AGW when the second IMS AGW is different from the first IMS AGW.

[0202] In some embodiments, the method for determining the IMS AGW provided by the present disclosure further includes:

[0203] In a case where the first IMS AGW is the same as the second IMS AGW, indication information sent by the first network function entity and used to indicate that the serving IMS AGW has not been changed is received.

[0204] Specifically, when the second IMS AGW is the same as the first IMS AGW, it indicates that the serving satellite has changed, but the IMS AGW serving the terminal has not changed. This situation occurs when the IMS AGW is deployed in a public IMS AGW manner.

[0205] The terminal receives the indication information sent by the first network function entity to indicate that the IMS AGW serving the terminal has not been changed. For example, the terminal receives a SIP 200OK message replied by the P-CSCF network element to indicate that the IMS AGW serving the terminal has not been changed.

[0206] The method for determining the IMS AGW provided by the embodiment of the present disclosure receives indication information sent by the first network function entity to indicate that the IMS AGW of the service terminal has not changed when the second IMS AGW is the same as the first IMS AGW, so as to learn that the IMS AGW of the service terminal has not changed, which is further conducive to achieving UE-SAT-UE communication.

[0207] Several specific embodiments are provided below to further illustrate the method for determining the IMS AGW provided by the present disclosure.

[0208] Example 1: Selection of IMS AGW on Satellite during Call Establishment

[0209] The IMS AGW is deployed on the satellite. When the UE makes a call, the IMS AGW deployed on the satellite is selected as the IMS AGW serving the UE. FIG8 is a fourth flowchart of the method for determining the IMS AGW provided by an embodiment of the present disclosure. FIG8 illustrates the process of selecting the IMS AGW deployed on the satellite during the call establishment process. Note that only the key network elements affected are drawn in the figure. Other network elements such as the Home Subscriber Server (HSS) network element, the Unified Data Management (UDM) network element, and the Application Server (AS) are not shown. As shown in FIG8 , the following steps are included:

[0210] (1) The UE completes registration with 5G via the gNB on satellite SAT1 (which deploys the gNB, UPF, and IMS AGW). The core network elements served are the AMF, SMF, and PCF. The PDU Session Anchor (PSA) UPF serving the UE is the terrestrial UPF.

[0211] (2) The UE completes registration in the IMS. The network element serving the IMS system is the P-CSCF network element, the Interrogating / Serving Call Session Control Function (I / S-CSCF) network element.

[0212] (3) The UE initiates a call and sends a SIP Invite message to the P-CSCF network element.

[0213] (4) The P-CSCF network element obtains the IMS AGW deployed on the satellite based on the IMS AGW deployment information on the satellite, and attempts to select the IMS AGW deployed on the satellite as the UE's access gateway for this call, triggering a request to the PCF network element for the UE's access network information. The P-CSCF network element uses the Rx interface to perform the Authentication and Authorization Request (AAR) / Authentication and Authorization Answer (AAA) message request and response process, or uses the service-based N5 interface to perform the Npcf_PolicyAuthorization_Subscribe operation to request the UE's access network information.

[0214] (5) The PCF network element requests the UE's access network information from the SMF network element through the Npcf_SMPolicyControl_UpdateNotify (notify session management policy control update) service operation.

[0215] (6) The SMF network element returns the UE's access network information to the PCF network element through the Npcf_SMPolicyControl_Update (session management policy control update) service operation. The access network information includes the UE's serving satellite identifier.

[0216] (7) The PCF returns the UE's access network information to the P-CSCF. The PCF uses the Rx interface to perform the RAR / RAA message request and response process, or uses the service-based N5 interface to perform the Npcf_PolicyAuthorization_Notify operation to return the UE's access network information to the P-CSCF.

[0217] (8) The P-CSCF network element selects the target IMS AGW as the access gateway for the UE based on the received serving satellite identifier, and requests the IMS AGW to allocate media resources.

[0218] The IMS AGW can be deployed on every satellite along with the gNB / UPF, or installed only on specific satellites as a public access gateway. Therefore, the target IMS AGW can be the IMS AGW deployed on the UE's serving satellite or a public IMS AGW deployed on another satellite.

[0219] When the deployment mode is that an IMS AGW is deployed on each satellite, the P-CSCF network element determines the serving satellite of the UE according to the received serving satellite identifier, and uses the IMS AGW deployed on the serving satellite of the UE as the target IMS AGW.

[0220] If the P-CSCF and IMS AGW have service-oriented interfaces, the target IMS AGW can also be selected using the network repository function (NF Repository Function, NRF) discovery method.

[0221] When the deployment mode is to install the public IMS AGW only on a specific satellite, the P-CSCF network element determines the public IMS AGW corresponding to the received serving satellite identifier based on the mapping relationship between the satellite identifier and the public IMS AGW, and uses the public IMS AGW corresponding to the received satellite identifier as the target IMS AGW.

[0222] The mapping relationship between the satellite identifier and the public IMS AGW can be dynamically adjusted according to the ephemeris information of each satellite.

[0223] (9) The P-CSCF network element triggers the dedicated resource establishment process to the PCF network element. The P-CSCF network element uses the Rx interface to perform the AAR / AAA message request and response process, or uses the service-based N5 interface to perform the Npcf_PolicyAuthorization_Create (create policy authorization) operation to trigger the dedicated resource establishment process to the PCF network element.

[0224] The request message carries indication information for indicating that the target IMS AGW deployed on the satellite is serving the UE. The indication information indicates that the access gateway of the UE has selected the IMS AGW deployed on the satellite.

[0225] (10) The PCF network element sends a dedicated resource establishment request to the SMF through the Npcf_SMPolicyControl_UpdateNotify service operation. The request message carries an indication that the target IMS AGW deployed on the satellite is serving the UE.

[0226] (11) After the SMF network element receives the indication information indicating that the target IMS AGW deployed on the satellite serves the UE, if the target IMS AGW is not a public IMS AGW, the UE's serving satellite and the satellite where the target IMS AGW is located are the same satellite, and the SMF network element inserts the UPF deployed on the satellite together with the target IMS AGW as the shunt UPF for the UE's call media flow; if the target IMS AGW is a public IMS AGW, the UE's serving satellite and the satellite where the target IMS AGW is located are not the same satellite, and the SMF network element inserts the UPF deployed on the UE's serving satellite as the shunt UPF for the UE's call media flow.

[0227] (12) The P-CSCF network element sends a SIP Invite message to the I / S-CSCF network element.

[0228] (13) The I / S-CSCF network element sends the SIP Invite message to the called UE.

[0229] (14) The interaction process between the UE and the peer UE includes 183 / PRACK / 200OK(PRACK) / UPDATE / 180, etc.

[0230] (15) The SIP 200 OK (Invite) sent by the called UE is sent to the UE's P-CSCF network element.

[0231] (16) The P-CSCF network element sends a SIP 200 OK (Invite) message to the UE, and adds indication information in the SIP message to indicate that the target IMS AGW deployed on the satellite is serving the UE.

[0232] (17) After the call is connected, the user plane media path of the UE is: UE<->gNB(SAT1)<->UPF(SAT1)<->IMS AGW(SAT1)<->the UE on the other end.

[0233] It should be noted that in this embodiment, when the P-CSCF network element receives the calling SIP Invite, it triggers the request for the UE's access network information and resource allocation (steps 4-11) from the PCF network element. In fact, these processes can also be triggered after other processes (such as receiving the SIP 183 message from the called UE).

[0234] In this embodiment, the calling UE is used as an example to illustrate the process of requesting the PCF network element for the UE's access network information and resource allocation (steps 4-11). The above process is also applicable to the called UE. For example, the called UE triggers the same process after receiving the SIP Invite message.

[0235] Example 2: Replacement of IMS AGW on Satellite, UE Triggers Media Path Update

[0236] After a UE connects to a call, during the call, the UE's serving satellite may change due to UE movement or satellite movement. This embodiment illustrates how the UE triggers an update of the user plane media path when the UE's serving satellite changes. Figure 9 is a fifth flow diagram of a method for determining an IMS AGW provided by an embodiment of the present disclosure, as shown in Figure 9, including the following steps:

[0237] (1) During a UE call, the serving satellite is SAT1, using gNB1, UPF1, and IMS AGW1 on SAT1. The user plane media path between UEs is: UE <-> gNB1(SAT1) <-> UPF1(SAT1) <-> AGW(SAT1) <-> peer UE. In the figure, SATx is the serving satellite for the peer UE.

[0238] (2) The UE's serving satellite is changed from SAT1 to SAT2, and the UE will be covered and served by SAT2.

[0239] (3) When the UE is replaced in the 5G system, that is, the access base station is changed from gNB1 to gNB2, the SMF selects UPF2 (SAT2) as the inserted UPF to forward the user plane media data between UEs.

[0240] (4) After the 5G upgrade is completed, since the IMS system has not been updated, the IMS AGW serving the UE remains unchanged and is still IMS AGW1 (SAT1). Therefore, the media path for inter-UE calls is: UE <-> gNB2 (SAT2) <-> UPF2 (SAT2) <-> IMS AGW1 (SAT1) <-> peer-side UE. The transmission from peer-side UE to IMS AGW1 (SAT1) is carried out via the inter-satellite link between SAT1 and SAT2.

[0241] (5) After the UE completes the 5G system replacement, the UE sends a SIP 200 OK (Invite) message through the P-CSCF network element. The SIP message contains information indicating that the target IMS AGW deployed on the satellite is serving the UE. The UE obtains information about the target IMS AGW used for this call. Since the UE's serving satellite has changed, the target IMS AGW may also need to be replaced.

[0242] The UE sends a SIP Re-Invite message or a SIP Update message to the P-CSCF network element to request a possible media path update. The message includes indication information for indicating that the serving satellite of the UE has been changed.

[0243] (6) The P-CSCF network element triggers a request to the PCF network element for the UE's access network information. The P-CSCF network element uses the Rx interface to perform the AAR / AAA message request and response process, or uses the service-based N5 interface to perform the Npcf_PolicyAuthorization_Subscribe operation to request the UE's access network information.

[0244] (7) The PCF network element requests the UE's access network information from the SMF network element through the Npcf_SMPolicyControl_UpdateNotify (notify session management policy control update) service operation.

[0245] (8) The SMF network element returns the UE's access network information to the PCF network element through the Npcf_SMPolicyControl_Update (session management policy control update) service operation. The access network information includes the UE's serving satellite identifier.

[0246] (9) The PCF returns the UE's access network information to the P-CSCF. The PCF uses the Rx interface to perform the RAR / RAA message request and response process, or uses the service-based N5 interface to perform the Npcf_PolicyAuthorization_Notify operation, returning the UE's access network information to the P-CSCF.

[0247] (10) Based on the received satellite identifier, the P-CSCF network element changes the target IMS AGW to IMS AGW2 (SAT2), that is, uses IMS AGW2 (SAT2) as the access gateway for the UE and requests that media resources be allocated to IMS AGW2 (SAT2).

[0248] (11) P-CSCF network element The PCF network element triggers the dedicated resource update process. The P-CSCF network element uses the Rx interface to perform the AAR / AAA message request and response process, or uses the service-based N5 interface to perform the Npcf_PolicyAuthorization_Create (create policy authorization) operation to trigger the dedicated resource update process to the PCF network element.

[0249] The request message carries indication information for indicating that the target IMS AGW deployed on the satellite is serving the UE, and the indication information indicates that the IMS AGW of the UE has selected IMS AGW2 (SAT2).

[0250] (12) The PCF sends a dedicated resource update request to the SMF using the Npcf_SMPolicyControl_UpdateNotify service operation. The request message carries an indication that the UE is being served by the target IMS AGW deployed on the satellite. The SMF updates the QoS dedicated bearer and UPF policies according to existing procedures.

[0251] (13-14) The P-CSCF network element sends a SIP Re-Invite message or a SIP Update message to the peer UE via the I / S-CSCF network element. The message includes the media resource information on the network side of the IMS AGW2 (SAT2).

[0252] (15-16) The peer UE returns a SIP 200 OK message, indicating that the peer has completed the update of the media resources.

[0253] (17) The P-CSCF returns a SIP 200 OK message to the UE. The message carries the access-side media resource information of the IMS AGW2 (SAT2), so that the UE can subsequently send user-plane media data to the IMS AGW2 (SAT2).

[0254] (18) The P-CSCF sends a request message to the IMS AGW1 (SAT1), requesting the IMS AGW1 (SAT1) to release the allocated media resources.

[0255] (19) The user plane media path of the UE will be updated to: UE<->gNB2(SAT2)<->UPF2(SAT2)<->IMS AGW2(SAT2)<->the UE on the opposite side.

[0256] The above process assumes that IMS AGWs are deployed on both UE's serving satellites. The same process applies to scenarios using a public IMS AGW. However, when using a public IMS AGW, a change in serving satellites may not result in an IMS AGW update. That is, in step 9, after the P-CSCF obtains the UE's new serving satellite information and determines that the current public IMS AGW is still in use, it directly responds with a SIP 200 OK message to the UE, eliminating steps 10-16 and 18.

[0257] Example 3: Replacement of IMS AGW on Satellite, Network-Triggered Media Path Update

[0258] The difference from the second embodiment is that the IMS network subscribes to the UE's access network information from the 5G system. When the UE's serving satellite changes, the IMS network triggers a media path update. Figure 10 is a sixth flow chart of the method for determining the IMS AGW provided by the embodiment of the present disclosure, as shown in Figure 10, including the following steps:

[0259] (1) After the call is established, the P-CSCF network element subscribes to the PCF network element for changes in the UE's access network information (including the changed UE's serving satellite identifier) ​​or the serving satellite change. The P-CSCF network element uses the Rx interface to perform AAR / AAA message request and response, or uses the service-based N5 interface to perform the Npcf_PolicyAuthorization_Subscribe operation to request the UE's access network information.

[0260] The subscription trigger point may include sending a message from the P-CSCF network element to the PCF network element during the call establishment process or after the call is established and connected.

[0261] (2) If the PCF network element has not subscribed to the SMF network element, the PCF network element subscribes to the SMF network element for the UE's access network information change (including the changed UE's service satellite identifier) ​​or the service satellite change process.

[0262] The PCF network element requests the UE's access network information from the SMF network element through the Npcf_SMPolicyControl_UpdateNotify (notify session management policy control update) service operation.

[0263] (3-6) During a UE call, the serving satellite is SAT1. gNB1, UPF1, and IMS AGW1 on SAT1 are used. The user plane media path between UEs is: UE <-> gNB1 (SAT1) <-> UPF1 (SAT1) <-> IMS AGW (SAT1) <-> peer UE. In the figure, SATx is the serving satellite for the peer UE.

[0264] The UE's serving satellite changes from SAT1 to SAT2, and the UE is covered and served by SAT2. The UE changes within the 5G system, meaning the access base station changes from gNB1 to gNB2. The SMF selects UPF2 (SAT2) as the intervening UPF to forward user-plane media data between UEs.

[0265] After the 5G transition, the IMS system remains unchanged, and the IMS AGW serving the UE remains unchanged, remaining IMS AGW1 (SAT1). Therefore, the inter-UE call media path is: UE <-> gNB2 (SAT2) <-> UPF2 (SAT2) <-> IMS AGW1 (SAT1) <-> peer-side UE. Data from the peer-side UE to IMS AGW1 (SAT1) is transmitted over the inter-satellite link between SAT1 and SAT2.

[0266] (7) Based on the subscription of the PCF network element, when the UE's service satellite is changed, the SMF network element notifies the PCF network element of the UE's new access network information (including the new service satellite identifier). The SMF network element returns the UE's new access network information to the PCF network element through the Npcf_SMPolicyControl_Update (session management policy control update) service operation.

[0267] (8) Based on the subscription of the P-CSCF network element, the PCF network element notifies the P-CSCF network element of the UE's new access network information (including the new serving satellite identifier). The PCF network element uses the Rx interface to perform the Re-Auth-Request (RAR) / Re-Auth-Answer (RAA) message request and response process, or uses the service-based N5 interface to perform the Npcf_PolicyAuthorization_Notify operation to return the UE's new access network information to the P-CSCF network element.

[0268] (9) Based on the received satellite identifier, the P-CSCF network element changes the target IMS AGW to IMS AGW2 (SAT2), that is, uses IMS AGW2 (SAT2) as the access gateway for the UE and requests that media resources be allocated to IMS AGW2 (SAT2).

[0269] (10) P-CSCF network element The PCF network element triggers the dedicated resource update process. The P-CSCF network element uses the Rx interface to perform the AAR / AAA message request and response process, or uses the service-based N5 interface to perform the Npcf_PolicyAuthorization_Create (create policy authorization) operation to trigger the dedicated resource update process to the PCF network element.

[0270] The request message carries indication information for indicating that the target IMS AGW deployed on the satellite is serving the UE, and the indication information indicates that the access gateway of the UE has selected IMS AGW2 (SAT2).

[0271] (11) The PCF sends a dedicated resource update request to the SMF using the Npcf_SMPolicyControl_UpdateNotify service operation. The request message carries an indication that the UE is being served by the target IMS AGW deployed on the satellite. The SMF updates the QoS dedicated bearer and UPF policies according to existing procedures.

[0272] (12-13) The P-CSCF network element sends a SIP Re-Invite message or a SIP Update message to the peer UE via the I / S-CSCF network element. The message includes the media resource information on the network side of the IMS AGW2 (SAT2).

[0273] (14-15) The peer UE returns a SIP 200 OK message, indicating that the peer has completed the update of the media resources.

[0274] (14-16) The P-CSCF network element sends a SIP Invite message or a SIP Update message to the UE. The message includes the access-side media resource information of the IMS AGW2 (SAT2).

[0275] (14-17) The UE returns a confirmation SIP 200 OK message.

[0276] (18) The P-CSCF sends a request message to the IMS AGW1 (SAT1), requesting the IMS AGW1 (SAT1) to release the allocated media resources.

[0277] (19) The user plane media path of the UE will be updated to: UE<->gNB2(SAT2)<->UPF2(SAT2)<->IMS AGW2(SAT2)<->the UE on the opposite side.

[0278] The above process assumes that IMS AGWs are deployed on both UE's serving satellites. The same process applies to scenarios using a public IMS AGW. However, when using a public IMS AGW, a change in serving satellites may not result in an IMS AGW update. In other words, in step 8, after the P-CSCF obtains the UE's new serving satellite information and determines that the current public IMS AGW is still in use, there is no need for the P-CSCF to trigger an IMS AGW update.

[0279] FIG11 is a schematic structural diagram of a first network function entity provided in an embodiment of the present disclosure. As shown in FIG11 , the first network function entity includes a memory 1120, a transceiver 1100, and a processor 1110, wherein:

[0280] The memory 1120 is used to store computer programs; the transceiver 1100 is used to send and receive data under the control of the processor 1110; the processor 1110 is used to read the computer program in the memory 1120 and perform the following operations:

[0281] subscribing to the access network information of the terminal from the second network function entity; or receiving first indication information sent by the terminal, and triggering a request for the access network information of the terminal from the second network function entity based on the first indication information, where the first indication information is used to indicate that a service satellite has been changed;

[0282] receiving access network information of the terminal sent by the second network function entity, where the access network information includes a serving satellite identifier, and the serving satellite identifier is an identifier of the replaced serving satellite;

[0283] A first IMS AGW serving the terminal is determined according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite, where the first IMS AGW is used to support an on-satellite IMS call of the terminal.

[0284] Specifically, the transceiver 1100 is configured to receive and send data under the control of the processor 1110 .

[0285] In FIG11 , the bus architecture may include any number of interconnected buses and bridges, specifically various circuits linked together by one or more processors represented by processor 1110 and memory represented by memory 1120. The bus architecture may also link together various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 1100 may be a plurality of components, namely, a transmitter and a receiver, providing a unit for communicating with various other devices over a transmission medium, such as a wireless channel, a wired channel, an optical cable, and the like. The processor 1110 is responsible for managing the bus architecture and general processing, and the memory 1120 may store data used by the processor 1110 when performing operations.

[0286] The processor 1110 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or a complex programmable logic device (CPLD). The processor may also adopt a multi-core architecture.

[0287] In some embodiments, determining the first IMS AGW serving the terminal according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite includes:

[0288] In a case where the deployment mode is that an IMS AGW is deployed on each satellite, determining the serving satellite of the terminal according to the serving satellite identifier;

[0289] Determine the IMS AGW deployed on the service satellite of the terminal as the first IMS AGW; or

[0290] In a case where the deployment mode is to deploy a public IMS AGW, determining the public IMS AGW corresponding to the serving satellite identifier according to a mapping relationship between the satellite identifier and the public IMS AGW;

[0291] The public IMS AGW corresponding to the serving satellite identifier is determined as the first IMS AGW.

[0292] In some embodiments, the operations further include:

[0293] The mapping relationship is adjusted according to the ephemeris information of each satellite.

[0294] In some embodiments, after determining the first IMS AGW serving the terminal, the method further includes:

[0295] Sending second indication information to the second network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on the satellite.

[0296] In some embodiments, the operations further include:

[0297] In a case where the first IMS AGW and the second IMS AGW are different, sending information about media resources allocated on the first IMS AGW to the terminal and a corresponding communication peer terminal of the terminal;

[0298] The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed.

[0299] In some embodiments, the operations further include:

[0300] Sending a release request message to the second IMS AGW; the release request message is used to request the second IMS AGW to release the allocated media resources.

[0301] In some embodiments, the operations further include:

[0302] In a case where the first IMS AGW is the same as the second IMS AGW, indication information for indicating that the IMS AGW serving the terminal has not changed is sent to the terminal.

[0303] It should be noted that the first network function entity provided in the embodiment of the present disclosure can implement all the method steps implemented in the method embodiment in which the execution subject is the first network function entity, and can achieve the same technical effects. The parts and beneficial effects of this embodiment that are the same as those of the method embodiment will not be described in detail here.

[0304] FIG12 is a schematic structural diagram of a second network function entity provided in an embodiment of the present disclosure. As shown in FIG12 , the second network function entity includes a memory 1220, a transceiver 1200, and a processor 1210, wherein:

[0305] The memory 1220 is used to store computer programs; the transceiver 1200 is used to send and receive data under the control of the processor 1210; the processor 1210 is used to read the computer program in the memory 1220 and perform the following operations:

[0306] When a first network function entity subscribes to access network information of a terminal, the access network information of the terminal is fed back to the first network function entity, where the access network information includes a serving satellite identifier, where the serving satellite identifier is an identifier of a replaced serving satellite, and where the serving satellite identifier is used to determine a first IMS AGW serving the terminal, where the first IMS AGW is used to support an on-satellite IMS call for the terminal.

[0307] Specifically, the transceiver 1200 is configured to receive and send data under the control of the processor 1210 .

[0308] In FIG12 , the bus architecture may include any number of interconnected buses and bridges, specifically various circuits linked together by one or more processors represented by processor 1210 and memory represented by memory 1220. The bus architecture may also link together various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 1200 may be a plurality of components, namely, a transmitter and a receiver, providing a unit for communicating with various other devices on a transmission medium, such as a wireless channel, a wired channel, an optical cable, and the like. The processor 1210 is responsible for managing the bus architecture and general processing, and the memory 1220 may store data used by the processor 1210 when performing operations.

[0309] The processor 1210 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or a complex programmable logic device (CPLD). The processor may also adopt a multi-core architecture.

[0310] In some embodiments, the operations further include:

[0311] receiving second indication information sent by the first network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on a satellite;

[0312] Based on the second indication information, determine the UPF serving the terminal.

[0313] It should be noted that the second network function entity provided in the embodiment of the present disclosure can implement all the method steps implemented in the method embodiment in which the execution subject is the second network function entity, and can achieve the same technical effects. The parts and beneficial effects of this embodiment that are the same as those of the method embodiment will not be described in detail here.

[0314] FIG13 is a schematic diagram of the structure of a terminal provided in an embodiment of the present disclosure. As shown in FIG13 , the terminal includes a memory 1320, a transceiver 1300, and a processor 1310, wherein:

[0315] The memory 1320 is used to store computer programs; the transceiver 1300 is used to send and receive data under the control of the processor 1310; the processor 1310 is used to read the computer program in the memory 1320 and perform the following operations:

[0316] First indication information is sent to a first network function entity, where the first indication information is used to indicate that a service satellite has been replaced and trigger the first network function entity to request access network information from a second network function entity, where the access network information includes a service satellite identifier, where the service satellite identifier is an identifier of the replaced service satellite, and where the service satellite identifier is used to determine a first IMS AGW serving the service, where the first IMS AGW is used to support on-board IMS calls.

[0317] In FIG13 , the bus architecture may include any number of interconnected buses and bridges, specifically linking together various circuits of one or more processors represented by processor 1310 and memory represented by memory 1320. The bus architecture may also link together various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 1300 may be a plurality of components, namely, a transmitter and a receiver, providing a unit for communicating with various other devices over a transmission medium, such as a wireless channel, a wired channel, an optical cable, and the like. For different user devices, the user interface 1330 may also be an interface capable of connecting external or internal devices as required, including but not limited to a keypad, a display, a speaker, a microphone, a joystick, and the like.

[0318] The processor 1310 is responsible for managing the bus architecture and general processing, and the memory 1320 can store data used by the processor 1310 when performing operations.

[0319] Optionally, the processor 1310 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or a complex programmable logic device (CPLD), and the processor may also adopt a multi-core architecture.

[0320] The processor calls the computer program stored in the memory to execute any of the methods provided by the embodiments of the present disclosure according to the obtained executable instructions. The processor and the memory can also be arranged physically separately.

[0321] In some embodiments, the operations further include:

[0322] In a case where the first IMS AGW and the second IMS AGW are different, receiving information about media resources allocated on the first IMS AGW sent by the first network function entity;

[0323] The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed.

[0324] In some embodiments, the operations further include:

[0325] In a case where the first IMS AGW is the same as the second IMS AGW, indication information sent by the first network function entity and used to indicate that the serving IMS AGW has not been changed is received.

[0326] It should be noted here that the above-mentioned terminal provided in the embodiment of the present disclosure can implement all the method steps implemented by the method embodiment in which the execution subject is the terminal, and can achieve the same technical effect. The parts and beneficial effects of this embodiment that are the same as those of the method embodiment will not be described in detail here.

[0327] FIG14 is a schematic diagram of a structure of an apparatus for determining an IMS AGW according to an embodiment of the present disclosure. As shown in FIG14 , an apparatus for determining an IMS AGW according to an embodiment of the present disclosure includes a first processing module 1410, a first receiving module 1420, and a first determining module 1430.

[0328] The first processing module 1410 is configured to subscribe to the access network information of the terminal from the second network function entity; or, receive first indication information sent by the terminal, and trigger a request for the access network information of the terminal from the second network function entity based on the first indication information, where the first indication information is used to indicate a change in the serving satellite;

[0329] A first receiving module 1420 is configured to receive the access network information of the terminal sent by the second network function entity, where the access network information includes a serving satellite identifier, and the serving satellite identifier is an identifier of the replaced serving satellite;

[0330] The first determining module 1430 is configured to determine a first IMS AGW serving the terminal according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite; the first IMS AGW is configured to support the on-satellite IMS call of the terminal.

[0331] In some embodiments, the first determining module 1430 is configured to:

[0332] In a case where the deployment mode is that an IMS AGW is deployed on each satellite, determining the serving satellite of the terminal according to the serving satellite identifier;

[0333] Determine the IMS AGW deployed on the service satellite of the terminal as the first IMS AGW; or

[0334] In a case where the deployment mode is to deploy a public IMS AGW, determining the public IMS AGW corresponding to the serving satellite identifier according to a mapping relationship between the satellite identifier and the public IMS AGW;

[0335] The public IMS AGW corresponding to the serving satellite identifier is determined as the first IMS AGW.

[0336] In some embodiments, the apparatus further comprises:

[0337] The adjustment module is used to adjust the mapping relationship according to the ephemeris information of each satellite.

[0338] In some embodiments, the apparatus further comprises:

[0339] The first sending module is configured to send second indication information to the second network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on a satellite.

[0340] In some embodiments, the apparatus further comprises:

[0341] a second sending module, configured to send information about media resources allocated on the first IMS AGW to the terminal and a corresponding communication peer terminal of the terminal when the first IMS AGW and the second IMS AGW are different;

[0342] The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed.

[0343] In some embodiments, the apparatus further comprises:

[0344] The third sending module is configured to send a release request message to the second IMS AGW; the release request message is used to request the second IMS AGW to release the allocated media resources.

[0345] In some embodiments, the apparatus further comprises:

[0346] The fourth sending module is configured to send, to the terminal, indication information indicating that the IMS AGW serving the terminal has not changed, when the first IMS AGW and the second IMS AGW are the same.

[0347] It should be noted that the device for determining the IMS AGW provided in the embodiment of the present disclosure can implement all the method steps implemented in the method embodiment in which the execution subject is the first network function entity, and can achieve the same technical effect. The parts and beneficial effects of this embodiment that are the same as those of the method embodiment will not be described in detail here.

[0348] FIG15 is a second structural diagram of an apparatus for determining an IMS AGW provided in an embodiment of the present disclosure. As shown in FIG15 , an embodiment of the present disclosure provides an apparatus for determining an IMS AGW, including a feedback module 1510;

[0349] Feedback module 1510 is configured to, when a first network function entity subscribes to the access network information of the terminal, feedback the access network information of the terminal to the first network function entity, where the access network information includes a serving satellite identifier, where the serving satellite identifier is an identifier of a replaced serving satellite, and where the serving satellite identifier is used to determine a first IMS AGW serving the terminal, where the first IMS AGW is used to support on-board IMS calls for the terminal.

[0350] In some embodiments, the apparatus further comprises:

[0351] A second receiving module is configured to receive second indication information sent by the first network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on a satellite;

[0352] The second determination module is used to determine the UPF serving the terminal based on the second indication information.

[0353] It should be noted that the device for determining the IMS AGW provided in the embodiment of the present disclosure can implement all the method steps implemented in the method embodiment in which the execution subject is the second network function entity, and can achieve the same technical effect. The parts and beneficial effects of this embodiment that are the same as those of the method embodiment will not be described in detail here.

[0354] FIG16 is a third structural diagram of an apparatus for determining an IMS AGW according to an embodiment of the present disclosure. As shown in FIG16 , an apparatus for determining an IMS AGW according to an embodiment of the present disclosure includes a fifth sending module 1610;

[0355] The fifth sending module 1610 is used to send first indication information to the first network function entity, where the first indication information is used to indicate that the service satellite has been replaced and trigger the first network function entity to request access network information from the second network function entity. The access network information includes a service satellite identifier, which is an identifier of the replaced service satellite. The service satellite identifier is used to determine the first IMS AGW of the service, and the first IMS AGW is used to support on-board IMS calls.

[0356] In some embodiments, the apparatus further comprises:

[0357] a third receiving module, configured to receive, when the first IMS AGW is different from the second IMS AGW, information about media resources allocated on the first IMS AGW sent by the first network function entity;

[0358] The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed.

[0359] In some embodiments, the apparatus further comprises:

[0360] The fourth receiving module is configured to receive, when the first IMS AGW is the same as the second IMS AGW, indication information sent by the first network function entity indicating that the serving IMS AGW has not changed.

[0361] It should be noted that the apparatus for determining the IMS AGW provided in the embodiment of the present disclosure can implement all the method steps implemented in the above-mentioned method embodiment in which the execution subject is a terminal, and can achieve the same technical effects. The parts and beneficial effects of this embodiment that are the same as those of the method embodiment will not be described in detail here.

[0362] It should be noted that the division of units / modules in the embodiments of the present disclosure is schematic and is merely a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional units in the various embodiments of the present disclosure may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0363] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a processor-readable storage medium. Based on this understanding, the technical solution of the present disclosure is essentially or the part that contributes to the relevant technology or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present disclosure. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0364] In some embodiments, a non-transitory readable storage medium is further provided. The non-transitory readable storage medium stores a computer program. The computer program is used to enable a processor to execute the method for determining the IMS AGW provided in the above-mentioned method embodiments.

[0365] Specifically, the above-mentioned non-transitory readable storage medium provided by the embodiment of the present disclosure can implement all the method steps implemented by the above-mentioned method embodiments, and can achieve the same technical effects. The parts and beneficial effects of this embodiment that are the same as the method embodiment will not be described in detail here.

[0366] It should be noted that the non-transitory readable storage medium can be any available medium or data storage device that can be accessed by the processor, including but not limited to magnetic storage (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO), etc.), optical storage (such as CDs, DVDs, BDs, HVDs, etc.), and semiconductor storage (such as ROMs, EPROMs, EEPROMs, non-volatile memories (NAND FLASH), solid-state drives (SSDs)), etc.

[0367] In some embodiments, a processor-readable storage medium is further provided. The processor-readable storage medium stores a computer program. The computer program is used to enable a processor to execute the method for determining the IMS AGW provided in the above method embodiments.

[0368] Specifically, the processor-readable storage medium provided in the embodiment of the present disclosure can implement all the method steps implemented in the above-mentioned method embodiments and can achieve the same technical effects. The parts and beneficial effects of this embodiment that are the same as those of the method embodiment will not be described in detail here.

[0369] In some embodiments, a computer-readable storage medium is further provided. The computer-readable storage medium stores a computer program. The computer program is used to enable a computer to execute the method for determining the IMS AGW provided in the above method embodiments.

[0370] Specifically, the above-mentioned computer-readable storage medium provided by the embodiment of the present disclosure can implement all the method steps implemented by the above-mentioned method embodiments, and can achieve the same technical effects. The parts and beneficial effects of this embodiment that are the same as the method embodiment will not be described in detail here.

[0371] In some embodiments, a communication device is further provided, wherein a computer program is stored in the communication device, and the computer program is used to enable the communication device to execute the method for determining the IMS AGW provided in the above-mentioned method embodiments.

[0372] Specifically, the above-mentioned communication device provided by the embodiment of the present disclosure can implement all the method steps implemented by the above-mentioned method embodiments, and can achieve the same technical effects. The parts and beneficial effects of this embodiment that are the same as the method embodiment will not be described in detail here.

[0373] In some embodiments, a chip product is further provided. The chip product stores a computer program, and the computer program is used to enable the chip product to execute the method for determining the IMS AGW provided in the above-mentioned method embodiments.

[0374] It should also be noted that the terms "first," "second," and the like in the embodiments of the present disclosure are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present disclosure can be implemented in an order other than that illustrated or described herein. Furthermore, the terms "first" and "second" generally distinguish objects of the same type, and do not limit the number of objects. For example, the first object can be one or more.

[0375] In the embodiments of the present disclosure, the term "and / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0376] In the embodiments of the present disclosure, the term "plurality" refers to two or more than two, and other quantifiers are similar thereto.

[0377] In the present disclosure, "determine B based on A" means that factor A must be considered when determining B. It is not limited to "determine B based on A alone", and should also include: "determine B based on A and C", "determine B based on A, C and E", "determine C based on A, and further determine B based on C", etc. It can also include using A as a condition for determining B, for example, "when A meets the first condition, use the first method to determine B"; for example, "when A meets the second condition, determine B"; for example, "when A meets the third condition, determine B based on the first parameter", etc. Of course, it can also be a condition that uses A as a factor in determining B, for example, "when A meets the first condition, use the first method to determine C, and further determine B based on C", etc.

[0378] The technical solution provided by the embodiments of the present disclosure can be applicable to a variety of systems, especially 5G systems. For example, the applicable system can be a global system of mobile communication (GSM) system, a code division multiple access (CDMA) system, a wideband code division multiple access (WCDMA) general packet radio service (GPRS) system, a long term evolution (LTE) system, a LTE frequency division duplex (FDD) system, a LTE time division duplex (TDD) system, an advanced long term evolution (LTE-A) system, a universal mobile telecommunication system (UMTS), a world-wide interoperability for microwave access (WiMAX) system, a 5G new air interface (NR) system, etc. These various systems include terminal equipment and network equipment. The system may also include a core network part, such as an evolved packet system (EPS), a 5G system (5GS), etc.

[0379] The terminal device involved in the embodiments of the present disclosure may be a device that provides voice and / or data connectivity to a user, a handheld device with wireless connection function, or other processing device connected to a wireless modem. In different systems, the name of the terminal device may also be different. For example, in a 5G system, the terminal device may be called User Equipment (UE). A wireless terminal device can communicate with one or more core networks (CN) via a radio access network (RAN). The wireless terminal device may be a mobile terminal device, such as a mobile phone (or "cellular" phone) and a computer with a mobile terminal device. For example, it may be a portable, pocket-sized, handheld, computer-built-in or vehicle-mounted mobile device that exchanges voice and / or data with a radio access network. For example, Personal Communication Service (PCS) phones, cordless phones, Session Initiated Protocol (SIP) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistants (PDAs), and other devices. The wireless terminal device may also be referred to as a system, a subscriber unit, a subscriber station, a mobile station, a mobile station, a remote station, an access point, a remote terminal device, an access terminal device, a user terminal device, a user agent, or a user device, but is not limited in the embodiments of the present disclosure.

[0380] The network device involved in the embodiments of the present disclosure may be a base station, which may include multiple cells providing services to terminals. Depending on the specific application scenario, the base station may also be called an access point, or may be a device in an access network that communicates with a wireless terminal device through one or more sectors on an air interface, or may be called another name. The network device may be used to interchange received air frames with Internet Protocol (IP) packets, acting as a router between the wireless terminal device and the rest of the access network, wherein the rest of the access network may include an Internet Protocol (IP) communication network. The network device may also coordinate the attribute management of the air interface. For example, the network device involved in the embodiments of the present disclosure may be a base transceiver station (BTS) in the Global System for Mobile communications (GSM) or code division multiple access (CDMA), a network device (NodeB) in wide-band code division multiple access (WCDMA), an evolutionary Node B (eNB or e-NodeB) in the long term evolution (LTE) system, a 5G base station (gNB) in the 5G network architecture (next generation system), a home evolved Node B (HeNB), a relay node, a femto, a pico, etc., and is not limited in the embodiments of the present disclosure. In some network structures, the network device may include a centralized unit (CU) node and a distributed unit (DU) node, and the centralized unit and the distributed unit may also be geographically separated.

[0381] Network devices and terminal devices can each use one or more antennas for Multiple Input Multiple Output (MIMO) transmission. MIMO transmission can be single-user MIMO (SU-MIMO) or multi-user MIMO (MU-MIMO). Depending on the form and number of antenna combinations, MIMO transmission can be 2D-MIMO, 3D-MIMO, FD-MIMO, or massive-MIMO. It can also use diversity transmission, precoding transmission, or beamforming transmission.

[0382] Those skilled in the art will appreciate that the embodiments of the present disclosure may be provided as methods, systems, or computer program products. Therefore, the present disclosure may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present disclosure may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage and optical storage, etc.) containing computer-usable program code.

[0383] The present disclosure is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present disclosure. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer-executable instructions. These computer-executable instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0384] These processor-executable instructions may also be stored in a processor-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the processor-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0385] These processor-executable instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0386] Obviously, those skilled in the art may make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is intended to include these modifications and variations.

Claims

1. A method for determining an IMS AGW, applied to a first network function entity, comprising: Subscribing to the second network function entity for the access network information of the terminal; Alternatively, receiving first indication information sent by the terminal, and triggering, based on the first indication information, requesting the second network function entity for the access network information of the terminal, where the first indication information is used to indicate that a serving satellite has been changed; receiving access network information of the terminal sent by the second network function entity, where the access network information includes a serving satellite identifier, and the serving satellite identifier is an identifier of the replaced serving satellite; A first IMS AGW serving the terminal is determined according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite, where the first IMS AGW is used to support an on-satellite IMS call of the terminal.

2. The method for determining an IMS AGW according to claim 1, wherein: The determining, according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite, a first IMS AGW serving the terminal includes: In a case where the deployment mode is that an IMS AGW is deployed on each satellite, determining the serving satellite of the terminal according to the serving satellite identifier; Determine the IMS AGW deployed on the service satellite of the terminal as the first IMS AGW; or In a case where the deployment mode is to deploy a public IMS AGW, determining the public IMS AGW corresponding to the serving satellite identifier according to a mapping relationship between the satellite identifier and the public IMS AGW; The public IMS AGW corresponding to the serving satellite identifier is determined as the first IMS AGW.

3. The method for determining an IMS AGW according to claim 2, wherein: The method further comprises: The mapping relationship is adjusted according to the ephemeris information of each satellite.

4. The method for determining an IMS AGW according to claim 1, wherein: After determining the first IMS AGW serving the terminal, the method further includes: Sending second indication information to the second network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on the satellite.

5. The method for determining an IMS AGW according to claim 1, wherein: The method further comprises: In a case where the first IMS AGW and the second IMS AGW are different, sending information about media resources allocated on the first IMS AGW to the terminal and a corresponding communication peer terminal of the terminal; The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed.

6. The method for determining an IMS AGW according to claim 5, wherein: The method further comprises: Sending a release request message to the second IMS AGW; the release request message is used to request the second IMS AGW to release the allocated media resources.

7. The method for determining an IMS AGW according to claim 6, wherein: The method further comprises: In a case where the first IMS AGW is the same as the second IMS AGW, indication information for indicating that the IMS AGW serving the terminal has not changed is sent to the terminal.

8. A method for determining an IMS AGW, applied to a second network function entity, comprising: When a first network function entity subscribes to access network information of a terminal, the access network information of the terminal is fed back to the first network function entity, where the access network information includes a serving satellite identifier, where the serving satellite identifier is an identifier of a replaced serving satellite, and where the serving satellite identifier is used to determine a first IMS AGW serving the terminal, where the first IMS AGW is used to support an on-satellite IMS call for the terminal.

9. The method for determining an IMS AGW according to claim 8, wherein: The method further comprises: receiving second indication information sent by the first network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on a satellite; Based on the second indication information, determine the UPF serving the terminal.

10. A method for determining an IMS AGW, applied to a terminal, comprising: First indication information is sent to a first network function entity, where the first indication information is used to indicate that a service satellite has been replaced and trigger the first network function entity to request access network information from a second network function entity, where the access network information includes a service satellite identifier, where the service satellite identifier is an identifier of the replaced service satellite, and where the service satellite identifier is used to determine a first IMS AGW serving the service, where the first IMS AGW is used to support on-board IMS calls.

11. The method for determining an IMS AGW according to claim 10, wherein: The method further comprises: In a case where the first IMS AGW and the second IMS AGW are different, receiving information about media resources allocated on the first IMS AGW sent by the first network function entity; The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed.

12. The method for determining an IMS AGW according to claim 11, wherein: The method further comprises: In a case where the first IMS AGW is the same as the second IMS AGW, indication information sent by the first network function entity and used to indicate that the serving IMS AGW has not been changed is received.

13. A first network function entity, comprising a memory, a transceiver, and a processor: a memory for storing computer programs; a transceiver for transmitting and receiving data under the control of the processor; A processor is configured to read the computer program in the memory and perform the following operations: subscribing to the access network information of the terminal from the second network function entity; or receiving first indication information sent by the terminal, and triggering a request for the access network information of the terminal from the second network function entity based on the first indication information, where the first indication information is used to indicate that a service satellite has been changed; receiving access network information of the terminal sent by the second network function entity, where the access network information includes a serving satellite identifier, and the serving satellite identifier is an identifier of the replaced serving satellite; A first IMS AGW serving the terminal is determined according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite, where the first IMS AGW is used to support an on-satellite IMS call of the terminal.

14. The first network function entity according to claim 13, wherein: The determining, according to the serving satellite identifier and the deployment mode of the IMS AGW on the satellite, a first IMS AGW serving the terminal includes: In a case where the deployment mode is that an IMS AGW is deployed on each satellite, determining the serving satellite of the terminal according to the serving satellite identifier; Determine the IMS AGW deployed on the service satellite of the terminal as the first IMS AGW; or In a case where the deployment mode is to deploy a public IMS AGW, determining the public IMS AGW corresponding to the serving satellite identifier according to a mapping relationship between the satellite identifier and the public IMS AGW; The public IMS AGW corresponding to the serving satellite identifier is determined as the first IMS AGW.

15. The first network function entity according to claim 14, wherein: The operations further include: The mapping relationship is adjusted according to the ephemeris information of each satellite.

16. The first network function entity according to claim 13, wherein: After determining the first IMS AGW serving the terminal, the method further includes: Sending second indication information to the second network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on the satellite.

17. The first network function entity according to claim 13, wherein: The operations further include: In a case where the first IMS AGW and the second IMS AGW are different, sending information about media resources allocated on the first IMS AGW to the terminal and a corresponding communication peer terminal of the terminal; The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed.

18. The first network function entity according to claim 17, wherein: The operations further include: Sending a release request message to the second IMS AGW; the release request message is used to request the second IMS AGW to release the allocated media resources.

19. The first network function entity according to claim 17, wherein: The operations further include: In a case where the first IMS AGW is the same as the second IMS AGW, indication information for indicating that the IMS AGW serving the terminal has not changed is sent to the terminal.

20. A second network function entity, comprising a memory, a transceiver, and a processor: A memory for storing a computer program; a transceiver for transmitting and receiving data under the control of the processor; and a processor for reading the computer program in the memory and performing the following operations: When a first network function entity subscribes to access network information of a terminal, the access network information of the terminal is fed back to the first network function entity, where the access network information includes a serving satellite identifier, where the serving satellite identifier is an identifier of a replaced serving satellite, and where the serving satellite identifier is used to determine a first IMS AGW serving the terminal, where the first IMS AGW is used to support an on-satellite IMS call for the terminal.

21. The second network function entity according to claim 20, wherein: The operations further include: receiving second indication information sent by the first network function entity; the second indication information is indication information indicating that the IMS AGW serving the terminal is the first IMS AGW deployed on a satellite; Based on the second indication information, determine the UPF serving the terminal.

22. A terminal comprising a memory, a transceiver, and a processor: A memory for storing a computer program; a transceiver for transmitting and receiving data under the control of the processor; and a processor for reading the computer program in the memory and performing the following operations: First indication information is sent to a first network function entity, where the first indication information is used to indicate that a service satellite has been replaced and trigger the first network function entity to request access network information from a second network function entity, where the access network information includes a service satellite identifier, where the service satellite identifier is an identifier of the replaced service satellite, and where the service satellite identifier is used to determine a first IMS AGW serving the service, where the first IMS AGW is used to support on-board IMS calls.

23. The terminal according to claim 22, wherein: The operations further include: In a case where the first IMS AGW and the second IMS AGW are different, receiving information about media resources allocated on the first IMS AGW sent by the first network function entity; The second IMS AGW is an IMS AGW determined to serve the terminal before the service satellite of the terminal is changed. The terminal according to claim 23 , wherein: The operations further include: In a case where the first IMS AGW is the same as the second IMS AGW, indication information sent by the first network function entity and used to indicate that the serving IMS AGW has not been changed is received.

25. A device for determining an IMS AGW, comprising: A first processing module, configured to subscribe to the access network information of the terminal from the second network function entity; Alternatively, receiving first indication information sent by the terminal, and triggering, based on the first indication information, requesting the second network function entity for the access network information of the terminal, where the first indication information is used to indicate that a serving satellite has been changed; A first receiving module is configured to receive access network information of the terminal sent by the second network function entity, where the access network information includes a serving satellite identifier, and the serving satellite identifier is an identifier of a replaced serving satellite; The first determining module is configured to determine a first IMS AGW serving the terminal according to the serving satellite identifier and a deployment mode of the IMS AGW on the satellite, where the first IMS AGW is configured to support an on-satellite IMS call of the terminal.

26. A device for determining an IMS AGW, comprising: A feedback module is configured to, when a first network function entity subscribes to the access network information of the terminal, feedback the access network information of the terminal to the first network function entity, where the access network information includes a serving satellite identifier, where the serving satellite identifier is an identifier of a replaced serving satellite, and where the serving satellite identifier is used to determine a first IMS AGW serving the terminal, where the first IMS AGW is used to support on-board IMS calls for the terminal.

27. A device for determining an IMS AGW, comprising: The fifth sending module is used to send first indication information to the first network function entity, where the first indication information is used to indicate that the service satellite has been replaced and trigger the first network function entity to request access network information from the second network function entity. The access network information includes a service satellite identifier, which is an identifier of the replaced service satellite. The service satellite identifier is used to determine the first IMS AGW of the service, and the first IMS AGW is used to support on-board IMS calls.

28. A non-transitory readable storage medium storing a computer program, wherein the computer program is configured to cause a processor to execute the method for determining an IMS AGW according to any one of claims 1 to 7, or the method for determining an IMS AGW according to any one of claims 8 to 9, or the method for determining an IMS AGW according to any one of claims 10 to 12.

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