A communication method and apparatus

Abstract

A communication method and device, the method comprising: a call session control function network element receiving first invitation request information of a first terminal, then obtaining first access information of the first terminal and second access information of a second terminal, the first access information indicating that the first terminal accesses through a satellite, and the second access information indicating that the second terminal accesses through the satellite; secondly, the call session control function network element determining, according to the first access information and the second access information, to establish direct communication for the first terminal and the second terminal; and finally, the call session control function network element sending first request information to a first network element to instruct to establish direct communication for the first terminal and the second terminal. The method can make the first terminal and the second terminal transmit IMS service data without passing through the ground, thereby reducing the time length of the IMS service between the first terminal and the second terminal, and greatly improving user experience.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0002] Future 5G and its evolved networks will not only need to meet diverse service requirements but also provide broader service coverage. Satellites, with their advantages of long communication distances, wide coverage, flexible networking, and independence from geographical and terrestrial equipment limitations, occupy an important position in the field of wireless communication.

[0003] Common services provided by terminal devices include voice communication. The IP Multimedia Subsystem (IMS) can provide users with voice, video, and information services. In satellite communication scenarios, terrestrial access network equipment or User Plane Function (UPF) network elements can be deployed on the satellite. However, due to the limited payload capacity of satellites, the IMS system may be located on the ground. When two terminal devices need to conduct voice communication services via a satellite access network, the voice data from one terminal device needs to pass through a UPF network element on one satellite, be transmitted to the terrestrial IMS system, then be transmitted from the terrestrial IMS system to a UPF network element on another satellite, and finally be transmitted to the other terminal device. However, due to the significant transmission delay between satellite and the ground, the voice communication between the two terminal devices will also experience substantial latency. Therefore, there is an urgent need to propose a communication method that can reduce the latency incurred when terminal devices conduct services via satellite. Summary of the Invention

[0004] A communication method and apparatus, which can be applied to satellite communication to reduce latency caused by services between terminal devices.

[0005] Firstly, this application provides a communication method, which can be executed by a call session control function network element or by the chip corresponding to that network element, without limitation. Specifically, it includes the following steps: the call session control function network element receives a first invitation request from a first terminal, the first invitation request request requesting communication with a second terminal; the call session control function network element obtains first access information and second access information, the first access information indicating that the first terminal accesses the network via satellite, and the second access information indicating that the second terminal accesses the network via satellite; the call session control function network element determines, based on the first access information and the second access information, that direct communication be established between the first terminal and the second terminal; the direct communication refers to the direct transmission of Internet Protocol Multimedia Subsystem (IMS) service data between the first terminal and the second terminal between a first satellite in the network accessed by the first terminal and a second satellite in the network accessed by the second terminal; the call session control function network element sends a first request information to the first network element, the first request information indicating direct communication between the first terminal and the second terminal.

[0006] After receiving an invitation request from the first terminal, the call session control function network element obtains first access information and second access information. The first access information indicates that the first terminal accesses the network via satellite, and the second access information indicates that the second terminal accesses the network via satellite. Based on the first and second access information, the call session control function network element determines that direct communication can be established between the first and second terminals, and sends a first request message to the first network element to instruct the first terminal and the second terminal to communicate directly. Since this direct communication is for IMS services between the first and second terminals, the IMS service data can be transmitted via satellite without going through the ground, thereby reducing the duration of IMS services between the first and second terminals and significantly improving the user experience.

[0007] In one possible implementation, the call session control function network element obtains the first access information by: the call session control function network element obtaining the first access information from the first terminal or the policy control function network element corresponding to the session of the first terminal, wherein the session of the first terminal is used to transmit data of the IMS service.

[0008] Through this implementation, the first access information obtained by the call session control function network element can come from the first terminal, or it can come from the policy control function network element corresponding to the session of the first terminal, thereby ensuring that the call session control function network element can flexibly receive the first access information of the first terminal.

[0009] In one possible implementation, the call session control function network element obtains the second access information, including:

[0010] The call session control function network element obtains the second access information from the second terminal or the policy control function network element corresponding to the session of the second terminal or the call session control function network element corresponding to the second terminal. The session of the second terminal is used to transmit the data of the IMS service.

[0011] Through this implementation, the second access information obtained by the call session control function network element can come from the second terminal, or it can come from the policy control function network element corresponding to the session of the second terminal, thereby ensuring that the call session control function network element can flexibly receive the second access information of the second terminal.

[0012] In one possible implementation, before the call session control function network element determines, based on the first access information and the second access information, that the first terminal and the second terminal should establish direct communication, the call session control function network element further includes: obtaining first network pass-through capability information, the first network pass-through capability information indicating that the first network supports the direct communication, and the first terminal and the second terminal accessing the network through the first network.

[0013] Through this implementation, the call session control function network element determines, based on the first access information and the second access information, that before the first terminal and the second terminal establish direct communication, it also needs to receive the first network pass-through capability information, thereby determining that the first network accessed by the first terminal and the second terminal supports direct communication.

[0014] In one possible implementation, before the call session control function network element determines, based on the first access information and the second access information, that direct communication between the first terminal and the second terminal is established, the method further includes: the call session control function network element receiving first direct communication subscription information and second direct communication subscription information, wherein the first direct communication subscription information indicates that direct communication between the first terminal is permitted, and the second direct communication subscription information indicates that direct communication between the second terminal is permitted.

[0015] Specifically, the call session control function network element can receive the first direct communication subscription information and the second direct communication subscription information from the unified data management network element.

[0016] In this implementation, the call session control function network element determines, based on the first access information and the second access information, that before the first terminal and the second terminal establish direct communication, it also needs to receive the first direct communication subscription information of the first terminal and the second direct communication subscription information of the second terminal to request the subscription data of the first terminal and the subscription data of the second terminal, thereby determining that the first terminal and the second terminal can perform the above-mentioned direct communication.

[0017] In one possible implementation, before the call session control function network element determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal, the method further includes: the call session control function network element obtaining first media feature support information and second media feature support information, wherein the first media feature support information indicates the media features of the first terminal for the IMS service, and the second media feature support information indicates the media features of the second terminal for the IMS service.

[0018] In this implementation, before determining that the first terminal and the second terminal establish direct communication based on the first access information and the second access information, the call session control function network element also needs to receive the first media feature support information of the first terminal and the second media feature support information of the second terminal, so as to accurately know that the first terminal and the second terminal support direct communication of the IMS service.

[0019] In one possible implementation, the first invitation request information includes direct communication request indication information, which indicates that the first terminal expects to conduct the direct communication with the second terminal.

[0020] In this implementation, the first invitation request information includes direct communication request indication information, so that the call session control function network element can accurately determine the task requested by the first terminal based on the direct communication request indication information, that is, the first terminal expects to conduct the above-mentioned direct communication with the second terminal.

[0021] In one possible implementation, the first request information includes the identification information of the first terminal and the identification information of the second terminal.

[0022] In this implementation, the first request information sent by the call session control function network element to the first network element includes the identification information of the first terminal and the identification information of the second terminal. Thus, the first network element can accurately allocate corresponding tunnels for the first terminal and the second terminal based on the identification information of the first terminal and the second terminal, thereby successfully establishing a transmission path between the first terminal and the second terminal to ensure that the first terminal and the second terminal can perform the above-mentioned direct communication.

[0023] In one possible implementation, the first request information includes Quality of Service (QoS) information for the direct communication.

[0024] In this implementation, the first request information sent by the call session control function network element to the first network element includes the Quality of Service (QoS) information for the direct communication. Therefore, the first network element can further establish a good transmission path for the direct communication between the first terminal and the second terminal based on the QoS information, thereby ensuring end-to-end service quality and further improving transmission latency.

[0025] In one possible implementation, the method further includes: the call session control function network element sending a first invitation response information to the first terminal, the first invitation response information indicating acceptance of the direct communication between the first terminal and the second terminal.

[0026] In this implementation method, after the call session control function network element determines that the first terminal and the second terminal have established direct communication based on the first access information and the second access information, it can also send a first invitation response information to the first terminal to inform the first terminal that it can conduct the above-mentioned direct communication with the second terminal.

[0027] Secondly, this application provides a communication device that can be applied to a call session control function network element and has the function of implementing the first aspect or any possible implementation of the first aspect. The hardware or software includes one or more units corresponding to the above functions, such as a receiving unit, a processing unit, and a transmitting unit.

[0028] Thirdly, this application also provides a communication device that can be applied to a call session control function network element and has the function of implementing the first aspect or any possible implementation of the first aspect. The device may include: a receiving module, a processing module, and a transmitting module.

[0029] Fourthly, this application also provides a communication system, which includes a call session control function network element for performing the method provided in the first aspect above, and may also include a ground terminal device, a policy control function network element, a unified data management network element, and a session management function.

[0030] One possible system includes user plane function network elements and access network equipment on a satellite.

[0031] It should be understood that ground-based terminal equipment, policy control function network elements, unified data management network elements, and session management functions, as well as satellite-based user plane function network elements and access network equipment, can be used to interact with the call session control function network element to assist the call session control function network element in determining whether the first terminal and the second terminal establish direct communication.

[0032] Fifthly, embodiments of this application also provide a computer storage medium storing a software program that, when read and executed by one or more processors, can implement the methods provided in the first aspect or any of the possible implementations described above.

[0033] Sixthly, embodiments of this application also provide a computer program product containing instructions that, when run on a computer, cause the method provided in the first aspect or any of the possible implementations therein to be executed.

[0034] In a seventh aspect, embodiments of this application also provide a chip system, which includes a processor for supporting call session control function network elements to implement the functions involved in the first aspect above.

[0035] In one possible design, the chip system also includes a memory for storing necessary program instructions and data for execution by the loading device. The chip system can be composed of chips or may include chips and other discrete components.

[0036] The technical effects that can be achieved by the second aspect or any possible implementation of the second aspect can be described with reference to the technical effects that can be achieved by the first aspect or any possible implementation of the first aspect; they will not be repeated here. Attached Figure Description

[0037] Figure 1 This is a schematic diagram illustrating an application scenario to which a communication method provided in this embodiment of the application is applicable;

[0038] Figure 2 This is a schematic diagram of the communication system architecture to which the communication method provided in the embodiments of this application is applicable;

[0039] Figure 3A This is a flowchart illustrating a communication method provided in an embodiment of this application;

[0040] Figure 3B This is a simplified flowchart illustrating an example of a communication method provided in this application.

[0041] Figure 4A This is a schematic diagram of a communication example process in a multi-IM CN scenario provided in this application embodiment;

[0042] Figure 4B This is a schematic diagram of a communication example process in a single IM CN scenario provided in the embodiments of this application;

[0043] Figure 5 This is a schematic flowchart illustrating an example of another communication method provided in the embodiments of this application;

[0044] Figure 6 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0045] Figure 7 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application. Detailed Implementation

[0046] This application provides a communication method and apparatus, wherein the method and apparatus are based on the same or similar technical concepts. Since the methods and apparatus solve problems in similar principles, the implementation of the apparatus and the method can refer to each other, and repeated parts will not be described again.

[0047] The following section will first explain some of the terms used in the embodiments of this application so that those skilled in the art can understand them.

[0048] 1) The call session control function network element involved in the embodiments of this application can be the call session control function (CSCF) network element in the IMS system architecture, which is responsible for session control.

[0049] The execution entity in this application embodiment can be a call session control function network element or a chip corresponding to the call session control function network element. The call session control function network element in this application embodiment can be a physical entity network element or a virtual network element. This application does not limit the specific form of the call session control function network element.

[0050] 2) The access network equipment involved in this application embodiment can be a device that provides access for terminal devices, including Radio Access Network (RAN) equipment and AN equipment. RAN equipment is mainly 3GPP network radio network equipment, while AN can be a non-3GPP defined access network device. RAN equipment is responsible for functions such as radio resource management, quality of service (QoS) management, data compression, and encryption on the air interface side. This RAN equipment can include various forms of base stations, such as macro base stations, micro base stations (also known as small stations), relay stations, access points, etc. In systems using different radio access technologies, the name of the equipment with base station functions may differ. For example, in 5th generation (5G) systems, it is called RAN or gNB (5G NodeB); in LTE systems, it is called evolved NodeB (eNB or eNodeB); in 3rd generation (3G) systems, it is called Node B, etc. This application does not limit the specific form of the access network equipment.

[0051] 3) The policy control function network element involved in this application embodiment can be a PCF network element in the communication system architecture, used to provide policy rules for network entities to implement, and can support a unified policy framework to manage network behavior and access subscription information of unified data storage. For example, in this application embodiment, the policy control network element is used to issue rules to the session management network element, and is also used to manage service flows, that is, to modify or delete the service quality parameters of service flows.

[0052] The execution entity of the embodiments of this application can be a policy control function network element or a chip corresponding to the policy control function network element. The policy control function network element in this application can be a physical entity network element or a virtual network element. This application does not limit the specific form of the policy control function network element.

[0053] 4) The Internet Protocol Multimedia Subsystem (IMS) involved in this application embodiment, namely the IP-based multimedia system, can also be called the IP Multimedia Subsystem. The IMS system provides a multimedia service and platform for next-generation IP-based mobile networks, oriented towards packet data exchange. It can meet the increasingly novel and diverse multimedia service needs of current end customers. Currently, IMS is considered a core technology of next-generation networks and an important way to solve the convergence of mobile and fixed networks, and to introduce differentiated services such as voice, data, and video triple convergence.

[0054] It should be noted that the IMS system mentioned in this application refers to all or part of the network elements in the IMS system, such as network elements related to call session control functions that handle session control, network elements related to media data, etc., which may correspond to different network elements in different contexts, and this application does not limit them.

[0055] 5) The access information involved in the embodiments of this application can be the access type indication information of the terminal. The access type indication information can indicate that the terminal accesses the network through satellite or indicates that the terminal accesses the network through other means. The access type indication information can also be access type information or access technology type information. This application does not make specific limitations on this.

[0056] 6) The Quality of Service (QoS) involved in the embodiments of this application can generally represent the sum of the characteristics and features of a service that can meet the specified and potential requirements, that is, the degree to which the service can meet the needs of the service recipient.

[0057] In this application, Quality of Service (QoS) can be represented as a technology for effectively managing network resources, providing end-to-end QoS guarantees for various services with different needs. Specifically, a network can utilize various underlying technologies to provide better service capabilities for specified network communications, thereby avoiding problems such as network latency and congestion. Moreover, for networks with limited capacity, especially for streaming multimedia applications such as Voice over Internet Protocol (VoIP) and Interactive Personality TV (IPTV), ensuring QoS is crucial because these media applications require fixed transmission rates and are sensitive to latency.

[0058] In summary, QoS can be used to measure the overall performance of services experienced by network users. For example, it can be measured by measuring relevant aspects of services such as packet loss rate, bit rate, throughput, transmission latency, availability, and jitter to measure the quality of network services.

[0059] 7) The media characteristics involved in the embodiments of this application can refer to the usage functions supported by the terminal. For example, the terminal device can be used for media features such as voice communication, video communication, or taking pictures. In addition, media characteristics can also be attributes of the terminal. This application does not specifically limit the specific attributes. In the embodiments of this application, the media characteristics involved are the voice communication media characteristics of the terminal device.

[0060] 8) The direct communication subscription information involved in the embodiments of this application can indicate that the terminal has subscribed to a preset function and can communicate directly via satellite to realize the preset function. This application does not specifically limit the content of the subscription.

[0061] 9) In the embodiments of this application, "multiple" refers to two or more.

[0062] In addition, it should be understood that in the description of this application, the words "first" and "second" are used only for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance or order.

[0063] Please refer to Figure 1 This is a schematic diagram illustrating a satellite mobile communication scenario to which the embodiments of this application can be applied. Figure 1As shown, in this satellite mobile communication system, satellite 1 carries base station 1 and user plane function network element 1, while satellite 2 carries base station 2 and user plane function network element 2. Terminal device 1 can access base station 1 on satellite 1 via wireless communication to communicate with satellite 1. Base station 1 on satellite 1 can establish a communication connection with base station 2 on satellite 2, and terminal device 2 can also access base station 2 on satellite 2 via wireless communication to communicate with satellite 2. When terminal device 1 transmits voice data to terminal device 2, the transmission follows path 1: terminal device 1's voice data is transmitted to satellite 1, then satellite 1 transmits the voice data to the ground-based IP multimedia subsystem (IMS) system, further transmitting the voice data from the IMS system to satellite 2, and finally from satellite 2 to terminal device 2. However, due to the large distance between the ground and the satellite, the voice communication latency between terminal device 1 and terminal device 2 is significant, resulting in a poor user experience. It should be noted that in this scenario, UPF may also be deployed on the ground. In this case, after the media data reaches the ground via the user plane network element on the satellite, it may first pass through the ground-deployed UPF and then through the IMS system. Alternatively, the media data may directly reach the IMS system after reaching the ground via the user plane network element on the satellite. This application does not limit this.

[0064] Therefore, this application provides a communication method that supports direct communication between terminal device 1 and terminal device 2 via satellite, thereby reducing the latency caused by IMS services between terminal device 1 and terminal device 2 and significantly improving the user experience. It should be noted that when mentioning IMS services in this application, voice communication is frequently used as an example.

[0065] It should be noted that the communication method provided in this application embodiment is not only applicable to the 5G system architecture described above, but also applicable to, but not limited to, long term evolution (LTE) communication systems, as well as various future wireless communication systems.

[0066] The following section provides a detailed introduction to the specific network elements / modules in the 5G system architecture.

[0067] refer to Figure 2As shown, the 5G system mainly includes: Network Slice Selection Function (NSSF) network elements, Network Exposure Function (NEF) network elements, Network Repository Function (NRF) network elements, Policy Control Function (PCF) network elements, Unified Data Management (UDM) network elements, Application Function (AF) network elements, Authentication Server Function (AUSF) network elements, Access and Mobility Management Function (AMF) network elements, Session Management Function (SMF) network elements, User Equipment (UE), (Radio) Access Network ((R)AN) equipment, User Plane Function (UPF) network elements, and Data Network (DN). For ease of description, the Policy Control Function network element can be simply referred to as the PCF network element, and the other network elements are similarly described and will not be elaborated further.

[0068] refer to Figure 2 As shown, Nnnsf, Nnef, Nausf, Nnrf, Namf, Npcf, Nsmf, Nudm, and Naf represent the service-based interfaces exhibited by NSSF, NEF, AUSF, NRF, SMF, PCF, SMF, UDM, and AF, respectively; (See reference) Figure 2 As shown, N1 is the reference point between the UE and the AMF, N2 is the reference point between the (R)AN and the AMF, N3 is the reference point between the (R)AN and the UPF, N4 is the reference point between the SMF and the UPF, and N6 is the reference point between the UPF and the DN.

[0069] PCF network elements: used to provide policy rules for network entities to implement, and can support a unified policy framework to manage network behavior and access subscription information of the Unified Data Store (UDR).

[0070] UDM network elements are used for unified management of user data, storage of authentication certificates / authentication parameters, and storage and management of permanent user IDs (or UE permanent identifiers (SUbscription Permanent Identifier, SUPI)) of the 5G system, as well as the registration and management of user service network elements (such as AMF, SMF, etc., which currently provide services to terminals).

[0071] SMF network elements are responsible for tunnel maintenance, IP address allocation and management, UP function selection, policy implementation and QoS control, billing data collection, roaming, etc.

[0072] UE: This refers to a handheld terminal, laptop computer, subscriber unit, cellular phone, smartphone, wireless data card, personal digital assistant (PDA) computer, tablet computer, wireless modem, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, machine type communication (MTC) terminal, or other device capable of accessing the network. The terminal device communicates with the access network equipment using some form of air interface technology.

[0073] (R)AN equipment: Equipment that provides access for terminal devices, including RAN equipment and AN equipment. RAN equipment is mainly 3GPP network wireless network equipment, while AN can be access network equipment defined outside of 3GPP. Radio Access Network (RAN) equipment: Primarily responsible for functions such as air interface-side radio resource management, quality of service (QoS) management, data compression, and encryption. The RAN equipment can include various forms of base stations, such as macro base stations, micro base stations (also known as small stations), relay stations, access points, etc. In systems employing different radio access technologies, the names of equipment with base station functions may differ. For example, in 5th generation (5G) systems, it is called RAN or gNB (5G NodeB); in LTE systems, it is called evolved NodeB (eNB or eNodeB); and in 3rd generation (3G) systems, it is called Node B, etc.

[0074] UPF (User Packet Protection) elements are used for routing and forwarding user data packets, data interaction with external data networks (DNs), QoS processing in the user plane, and implementation of flow control rules (e.g., gating, redirection, traffic redirection). Data networks (DNs) refer to the service network that provides data transmission services to users, such as IMS (IP Multimedia Service), the Internet, etc. Examples include carrier services, Internet services, or third-party services. The UE accesses the data network (DN) through a PDU (Packet Data Unit) session established between the UE and the DN.

[0075] In the core network, each network element can also be called a functional entity or device. It can be a network element implemented on dedicated hardware, a software instance running on dedicated hardware, or an instance of virtualized function on an appropriate platform. For example, the virtualization platform mentioned above can be a cloud platform.

[0076] It should be noted that, Figure 2 The architecture of the communication system shown is not limited to the network elements shown in the figure, but may also include other devices not shown in the figure. These will not be listed here.

[0077] It should be noted that the embodiments of this application do not limit the distribution form of each network element. Figure 2 The distribution shown is merely exemplary and is not intended to limit the scope of this application.

[0078] For ease of explanation, all subsequent references to this application will be made to it. Figure 2 The network element shown is used as an example for illustration, and network element XX is directly abbreviated as XX. For example, SMF network element is abbreviated as SMF. It should be understood that all network element names in this application are merely examples and may be referred to by other names in future communications, or the network element involved in this application may be replaced by other entities or devices with the same function in future communications. This application does not limit these possibilities. This is a unified explanation here and will not be repeated later.

[0079] It should be noted that all names of messages and information in this application are merely examples and may be other names; this application does not limit them. It should be understood that a message or information from network element 1 to network element 2 can be a message sent directly from network element 1 to network element 2, or it can be sent indirectly. For example, network element 1 first sends a message to network element 3, and then network element 3 sends a message to network element 2. Ultimately, the message or information is sent to network element 2 through one or more network elements.

[0080] The IMS system architecture in the embodiments of this application will be described in detail below.

[0081] An IMS system includes one or more call session control functions (CSCF), media gateway control functions (MGCF) network elements, an IMS media gateway, a multimedia resource function processor, a subscription locator function (SLF), an interrupt gateway control function, and an application server.

[0082] The main components typically used in an IMS system include: Home Subscriber Service, Call Session Control Function (CSCF) network element, security gateway, IP media server, and application server.

[0083] The Home User Service (HSS) primarily stores user and service-related data, such as user identity, registration information, access parameters, and service trigger information. HSS also provides user location and authentication capabilities.

[0084] The call session control function network element consists of multiple sub-components, specifically including: Proxy-Call Session Control Function (P-CSCF) network element, Interrogation-Call Session Control Function (I-CSCF) network element, and Serving-Call Session Control Function (S-CSCF) network element.

[0085] The P-CSCF network element is the first point of contact for users accessing the IMS network during service applications. It is responsible for proxying all SIP signaling and completing call routing control; providing QoS resource reservation; supporting SIP signaling compression to improve bandwidth utilization efficiency of the air interface; providing NAT control to support NAT traversal for enterprise networks; and maintaining a security association with the UE to protect the privacy and integrity of signaling between the UE and the UE. It may manifest as an AF (Automatic AF) and interact with network elements such as the PCF (Programmable Component Filter).

[0086] I-CSCF element: The unified entry point for the user's home network, responsible for the allocation of S-CSCF and the query of the called party's S-CSCF. It also performs IMS inter-domain topology hiding function.

[0087] S-CSCF network element: The service switching center of the IMS network, mainly responsible for receiving and processing UE registration requests, user management, session control, service switching, service control, SIP information processing, billing, etc., and can trigger SIP requests to the corresponding AS according to the application's triggering principles. It can interact with UDM network elements.

[0088] It should be noted that the CSCF network elements corresponding to terminal device 1 and terminal device 2 can be the same or different, and this application does not limit this. The multiple IM CN (IP multi-media core network) mentioned in the specification refers to different CSCF network elements corresponding to terminal device 1 and terminal device 2, while single IM CN refers to the same CSCF network element corresponding to terminal device 1 and terminal device 2.

[0089] A security gateway serves as a communication channel between telecommunications networks, and between an enterprise and a telecommunications network. It primarily controls the entry and exit of messages through NAT (Network Address Translation) servers and firewalls, and may also perform other security functions, such as packet filtering. In addition, a security gateway also has the following functions: strengthening security policies between IMS domains, protecting control plane messages entering and leaving IMS domains, and setting and maintaining IPsec Security Associations (SAs).

[0090] An IP media server possesses all the necessary streaming media capabilities, providing rich multimedia messages such as text. It manages the related encoder (encoder / decoder) and streaming media transcoding, as well as echo cancellation, sound detection, and sound generation. The IP media server can also provide stream multiplication and streaming broadcasting to meet the needs of conferencing applications and can connect to circuit-switched networks.

[0091] The application server provides multimedia services to the IMS network, primarily offering access to all other IMS components such as SIPServlet. The application server can also be used to deploy new services; due to IMS's modular architecture, new service deployments can be completed simply by replacing or upgrading the application server. This strategy is entirely different from the previous vertical model, where services were always deployed as a single point of solution, with each service using its own proprietary set of equipment. Application servers can reside on the home network or a third-party network; if located on a third-party network, they cannot interface with the HSS. Because the application servers are OSA (Open Services Architecture) application servers, they can securely access IMS from external networks and connect to the GSM CAMEL (Mobile Enhanced Logic Custom Application) server.

[0092] This application provides a communication method that can be applied to... Figure 1Satellite communication scenarios, and applicable to, but not limited to, other satellite communication scenarios. Figure 2 The 5G system architecture shown is illustrated, and the method can be executed by the network element involved in this application, or by the chip corresponding to the network element involved. The network element in this application can be a physical entity network element or a virtual network element. This application does not specifically limit the form of the network element involved.

[0093] See Figure 3A As shown in the figure, this is a flowchart illustrating a communication method provided in an embodiment of this application. The method may include the following steps:

[0094] S301A: The call session control function network element receives the first invitation request information from the first terminal.

[0095] For example, step S301A can be referred to as follows: Figure 3B The simplified process shown in the example is S301B, where the CSCF network element receives the first invitation request information from UE1.

[0096] In one implementation, the call session control function network element receives a first invitation request information from a first terminal, including: the first invitation request information includes direct communication request indication information, which indicates that the first terminal expects to communicate directly with the second terminal.

[0097] It should be understood that the first invitation request information is the invitation party initiating a session request to the invitee. For example, if the first terminal is the inviter and the second terminal is the invitee, and the first terminal invites the second terminal to join a session, and the first terminal needs to request a voice communication session with the second terminal, then the first invitation request information sent by the first terminal is used to request direct communication with the second terminal.

[0098] In addition, the direct communication involved in this application refers to the direct transmission of Internet Protocol Multimedia Subsystem (IMS) service data between the first terminal and the second terminal via a first satellite in the first terminal access network and a second satellite in the second terminal access network.

[0099] Optionally, the first invitation request information may also include the identity information of the first terminal and the identity information of the second terminal.

[0100] It should be noted that the first invitation request information may also include access type indication information for the first terminal and / or media feature support information for the first terminal. The access type indication information for the first terminal indicates that the first terminal accesses the network via satellite; the media feature support information for the first terminal can be used to indicate that the first terminal supports the media features of IMS services for direct voice communication.

[0101] The media features supported by the UE1 may include the voice data encoding and decoding methods supported by the first terminal for the aforementioned direct voice communication, and this application does not specifically limit them.

[0102] In one implementation, the first invitation request information includes access network information (P-Access-Network-Info, PANI). If the PANI includes access type information, then the access type indication information is the access type information, which indicates satellite access, such as low-Earth orbit (LEO), medium-Earth orbit (MEO), or high-Earth orbit (HEO) satellite access. This application does not specifically limit the access type. If the PANI includes access technology type information, then the access type indication information is the access technology type information, which indicates the satellite access technology, such as LEO, MEO, or HEO satellite access technology. This application does not specifically limit the access technology type.

[0103] S302A: The call session control function network element obtains the first access information and the second access information.

[0104] In one implementation, the call session control function (CSC) network element acquires first access information and second access information, including: the CSC network element can acquire first access information received from a first terminal or a policy control function network element corresponding to a session of the first terminal, wherein the session of the first terminal is used to transmit data for the IMS service; the CSC network element acquires second access information from a second terminal or a policy control function network element corresponding to a session of the second terminal or a call session control function network element corresponding to the second terminal, wherein the session of the second terminal is used to transmit data for the IMS service. The first access information indicates that the first terminal accesses the network via satellite, and the second access information indicates that the second terminal accesses the network via satellite.

[0105] It should be noted that the first access information and the second access information can also be used as access type indication information to indicate that the first terminal and the second terminal access via satellite. For details, please refer to step S301 above, which will not be elaborated here.

[0106] S303A: The call session control function network element determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal.

[0107] In one implementation, before the call session control function network element determines, based on the first access information and the second access information, that the first terminal and the second terminal establish direct communication, the method further includes: the call session control function network element obtaining first network pass-through capability information, which indicates that the first network supports the direct communication, and the first terminal and the second terminal access each other through the first network.

[0108] Specifically, the call session control function network element can obtain the first network pass-through capability information from the policy control function network element. It can also receive the first network pass-through capability information from other network elements; this application does not specifically limit this.

[0109] When the call session control function network element obtains the first network pass-through capability information from the policy control function network element, it may specifically include: the call session control function network element sending authentication and authorization request information to the policy control function network element. Optionally, the authentication and authorization request information includes network direct communication capability request information, which requests information on whether the network supports direct communication. Further, the call session control function network element receives authentication and authorization response information from the policy control function network element, which may carry the first network pass-through capability information.

[0110] In one embodiment, before the call session control function network element determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal, the method further includes: the call session control function network element receiving the first direct communication subscription information and the second direct communication subscription information, wherein the first direct communication subscription information indicates that the first terminal is allowed to communicate directly, and the second direct communication subscription information indicates that the second terminal is allowed to communicate directly.

[0111] Specifically, the call session control function network element can obtain first and second direct communication subscription information from the unified data management network element. Before receiving the first and second direct communication subscription information from the unified data management network element, the call session control function network element needs to send a subscription data request message from the first terminal to the unified data management network element to request the subscription data of the first terminal. This subscription data request message may include subscription data type information, which may indicate whether the subscription data type is satellite communication subscription data or direct communication subscription data. This application can limit the indication function of the subscription data type information according to the actual situation.

[0112] It should be understood that the aforementioned first direct communication subscription information and second direct communication subscription information may indicate whether direct communication between the first terminal and the second terminal is permitted or not permitted, depending on the actual situation.

[0113] In one embodiment, before the call session control function network element determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal, the method further includes: the call session control function network element acquiring first media characteristic support information of the first terminal and second media characteristic support information of the second terminal; the first media characteristic support information indicates the media characteristics of the first terminal for the IMS service, and the second media characteristic support information indicates the media characteristics of the second terminal for the IMS service.

[0114] Specifically, the call session control function network element can obtain first media feature support information from the first terminal and second media feature support information from the second terminal. The media feature support information can be used to indicate whether the terminal supports media features for direct voice communication or not; this application does not specifically limit this. Furthermore, the media features supported by the terminal can include the voice data encoding / decoding methods supported by the first terminal for the aforementioned direct voice communication; this application does not specifically limit this either.

[0115] In one implementation, the first media feature support information and the second media feature support information of the second terminal need to match, that is, all or part of the media support information of the first terminal must be consistent with all or part of the second media feature support information.

[0116] It should be noted that the call session control function network element can only determine that the first terminal and the second terminal can establish direct communication if the information obtained in the above embodiments all indicate that the first terminal, the second terminal, and the network support direct communication. If any one of them does not support direct communication, then it is determined that the first terminal and the second terminal cannot establish direct communication.

[0117] For example, in steps S302A-S303A, the call session control function network element determines the information exchanged before the first terminal and the second terminal establish direct communication, which can be referred to as follows: Figure 3B The S302B shown indicates the satellite access type, direct access capability information, and direct access support information between CSCF and PCF / UDM.

[0118] The step S302A-S303A, where the call session control function network element determines the establishment of direct communication between the first terminal and the second terminal, can be referenced. Figure 3B The simplified process illustrated in the example includes S305B, where the CSCF determines acceptance of direct voice communication. Additionally, before the call session control function element determines that the first and second terminals have established direct communication, it also includes sending a second invitation request to the second terminal and receiving a second invitation response from the second terminal to ensure that the second terminal agrees to accept the establishment of direct communication with the first terminal. (See reference...) Figure 3BThe example shown simplifies the process from S303B to S304B.

[0119] S304A: The call session control function network element sends a first request message to the first network element, which indicates that the first terminal and the second terminal can communicate directly.

[0120] For example, in step S304A, the call session control function network element sending the first request information to the first network element can be referred to... Figure 3B The example shown simplifies the process by stepping into S306B, which involves establishing direct communication information.

[0121] Furthermore, step S307B can be used to instruct the SMF network element to allocate a tunnel for the S-UPF1 corresponding to the session of the first terminal and to allocate a tunnel for the S-UPF2 corresponding to the session of the second terminal, thereby establishing a tunnel for direct communication between the first terminal and the second terminal. This step can be referred to... Figure 3B The simplified process shown in the example, specifically S307B-S309B, does not specifically limit how to establish a communication tunnel (transmission path).

[0122] Optionally, the first request information may include the address information of the first terminal and the address information of the second terminal, or may include other identification information of the first terminal and the second terminal. Furthermore, the first request information may also include Quality of Service (QoS) information used for direct communication between the first terminal and the second terminal.

[0123] In one implementation, after determining that direct communication has been established between the first terminal and the second terminal, the call session control function network element can further send a first invitation response message to the first terminal, which indicates acceptance of the direct communication between the first terminal and the second terminal. This step can be referred to... Figure 3B The example shown simplifies the process using S310B.

[0124] It should be noted that if the call session control function network element determines that the first terminal and the second terminal cannot establish direct communication, the call session control function network element sending a first invitation response message to the first terminal can be used to indicate that the first terminal and the second terminal are refused direct communication. Furthermore, in this application, the first network element may include a policy control function network element and a unified data management network element, or it may include other network elements; this application does not impose specific limitations on this.

[0125] It should be noted that in the communication method provided in this application, the first terminal and the second terminal can perform the above steps through the same call session control function network element, which is a single IM CN scenario; the first terminal and the second terminal can also perform the above steps through different call session control function network elements, which is a multi-IM CN scenario.

[0126] In summary, Figure 3A The present application provides a communication method in which a call session control function (CSC) network element receives a first invitation request from a first terminal, then acquires first access information of the first terminal and second access information of a second terminal. The first access information indicates that the first terminal accesses via satellite, and the second access information indicates that the second terminal accesses via satellite. Next, based on the first and second access information, the CSC network element determines that direct communication should be established between the first and second terminals. Finally, the CSC network element sends a first request to the first network element to indicate that direct communication should be established between the first and second terminals. This method allows the transmission of IMS service data between the first and second terminals to bypass the terrestrial route, thereby reducing the duration of IMS service communication between the first and second terminals and significantly improving the user experience.

[0127] Based on the communication method provided in the above embodiments, the following detailed description of the method of this application is based on a specific embodiment. This embodiment mainly enables direct voice communication between terminals via satellite in a multi-IM CN scenario. In this embodiment, UE1 and UE2 can access the network through a corresponding satellite, that is, UE1 can access the network through a first satellite, and UE2 can access the network through a second satellite. Each satellite includes an access device (e.g., base station gNB1, gNB2) and a UPF network element, and UE1 and UE2 are respectively provided by a corresponding CSCF network element. That is, a call session control function corresponding to UE1 can be represented by a CSCF#1 network element, and a call session control function corresponding to UE2 can be represented by a CSCF#2 network element. The call control function CSCF#1 network element includes one or more of P-CSCF#1 network elements, I-CSCF#1 network elements, and S-CSCF#1 network elements, and the call control function CSCF#2 network element includes one or more of P-CSCF#2 network elements, I-CSCF#2 network elements, and S-CSCF#2 network elements.

[0128] refer to Figure 4A As shown, the network-side execution object involved in this embodiment is a network element, and the CSCF network element in this embodiment is the aforementioned Figure 3A The call session control function network element in this embodiment, specifically the UDM network element described above. Figure 3A In the unified data management, the PCF network element in this embodiment is as described above. Figure 3A The policy control function network element in this embodiment, the UPM network element is as described above. Figure 3A The specific implementation process of the user plane function network element in this embodiment is as follows:

[0129] S401: Terminal UE1 sends a first invitation request to the P-CSCF#1 network element, which requests communication with the second terminal UE2.

[0130] Correspondingly, the P-CSCF#1 network element receives the first invitation request information.

[0131] Optionally, the first invitation request message can be an INVITE request message.

[0132] Specifically, the first invitation request information includes the identity information of UE1 and UE2. For example, the identification information of UE1 and the identification information of UE2.

[0133] Optionally, the first invitation request information includes first access type indication information, which indicates that UE1 accesses the network via satellite. It should be noted that the first access type indication information may also indicate other access types. Unless otherwise specified, this first access type indication information indicates that UE1 accesses the network via satellite.

[0134] In the first implementation, the first invitation request information includes access network information (P-Access-Network-Info, PANI), and the PANI contains first access type information. That is, the aforementioned first access type indication information is access type information, which indicates that UE1 accesses the network via satellite. This application does not limit how the first access type information specifically instructs UE1 to access the network via satellite. For example, UE1 can access the network via low-Earth orbit satellite, UE1 can access the network via medium-Earth orbit satellite, UE1 can access the network via high-Earth orbit satellite, etc.

[0135] In the second implementation, the first invitation request information includes a PANI (P-Access-Network-Info). When the PANI contains first access technology type (RAT Type) information, the first access type indication information is the first access technology type information, which indicates the satellite access technology type. This application does not limit how the first access technology type information indicates the satellite access technology type; for example, it can be low-Earth orbit satellite access technology, medium-Earth orbit satellite access technology, high-Earth orbit satellite access technology, etc.

[0136] Optionally, the first invitation request information may further include first direct communication request indication information and first media feature support information; wherein, the first direct communication request indication information indicates that UE1 requests direct voice communication with another terminal UE2 via satellite, and the first direct voice communication means that the voice communication data between UE1 and UE2 only passes through UE1, the satellite, and UE2. The first media feature support information indicates that UE1 supports media features for direct voice communication. It should be noted that the first media feature support information may also indicate that UE1 does not support media features for direct voice communication. Unless otherwise specified, the first media feature support information indicates that UE1 supports media features for direct voice communication, and the media features supported by UE1 may include the voice data encoding and decoding methods supported by UE1 for the aforementioned direct voice communication. It should be understood that direct voice communication is the same as the aforementioned direct communication.

[0137] S402: P-CSCF#1 network element initiates the first authentication and authorization request to PCF network element.

[0138] Accordingly, the PCF network element receives the first authentication and authorization request information.

[0139] Optionally, the first authentication authorization request information can be an Authentication Authorization Request Message, also known as AA-Request information or AAR information.

[0140] The first authentication and authorization request requests authentication and authorization for whether UE1's voice communication complies with Policy and Charging Control supervision.

[0141] In one implementation, if the first invitation request information received by the P-CSCF#1 network element includes one or more of the first access type indication information and the first direct communication request indication information in S401 above, then the first authentication and authorization request information sent by the P-CSCF#1 network element to the PCF network element includes the first network direct communication capability request information, which requests information on whether the network supports direct communication between satellites.

[0142] It should be understood that direct communication between satellites can establish links between them for transmitting voice data. Furthermore, the aforementioned network is composed of satellites and ground-based network elements.

[0143] In the second implementation, if the first invitation request information received by the P-CSCF#1 network element includes one or more of the first access type indication information and the first direct communication request indication information mentioned in S401 above, then the first authentication and authorization request information sent by the P-CSCF#1 network element to the PCF network element includes the first direct communication indication information, which indicates that UE1 needs to communicate directly. If the first authorization request information includes the first direct communication indication information, then the first authentication and authorization request information requests authentication and authorization of whether UE1's direct voice communication complies with policy and charging control supervision.

[0144] S403: The PCF network element sends the first authentication and authorization response information to the P-CSCF#1 network element.

[0145] Correspondingly, the P-CSCF#1 network element receives the first authentication and authorization response information.

[0146] Optionally, the first authentication and authorization response information can be an Authentication Authorization Answer Message, also known as an AA-Answer message or AAA message.

[0147] Optionally, the first authentication and authorization response information includes access type indication information, which indicates that the first terminal accesses the network via satellite.

[0148] In the first implementation, the first invitation request information in step S401 does not include access type indication information, while the first authentication and authorization response information in step S403 includes first access type indication information. This first access type indication information is the same as the first access type indication in step S401, and will not be described again here.

[0149] In the second implementation, the first invitation request information in step S401 includes first access type indication information, and the first access type indication information in step S401 is the first access type information. The first authentication and authorization response information in step S403 includes first access type indication information, which is the first access technology type information in step S401. This first access technology type information is the same as the first access technology type information in step S401, and will not be described again here.

[0150] In the third implementation, if the first authentication and authorization request information includes one or more of the first network direct communication capability request information and the first direct communication indication information, then the first authentication and authorization response information includes the first network direct communication capability information and the first direct communication authorization result information.

[0151] It should be understood that the first direct communication authorization result information indicates whether UE1 is allowed or not allowed to perform the aforementioned direct voice communication. The first network direct communication capability information indicates whether the network accessed by UE1 supports or does not support inter-satellite direct communication, which is the same as described in step 2.

[0152] In the fourth implementation, if the first authentication and authorization request information contains first direct communication indication information, then the first authentication and authorization response information contains first direct communication authorization result information.

[0153] It should be noted that steps S402 and S403 above are optional steps.

[0154] S404: P-CSCF#1 network element sends a second invitation request to S-CSCF#1 network element.

[0155] Correspondingly, the S-CSCF#1 network element receives the second invitation request information.

[0156] It should be understood that the P-CSCF#1 network element, S-CSCF#1 network element, and I-CSCF#1 network element are all network elements serving UE1, that is, they belong to the originating network.

[0157] In one implementation, the second invitation request information includes one or more of first access type indication information and first network direct communication capability information. This first access type indication information and first network direct communication capability information are the same as those in step S403 described above.

[0158] In the second implementation, the second invitation request information includes first direct communication indication information, which is the same as the first direct communication indication information in the first authentication and authorization request information in step S402 above.

[0159] The second implementation method can specifically include the following situations:

[0160] In the first case, if at least one of the first invitation request information in step S401 and the first authentication and authorization response information in step S403 contains the first access type indication information, then the second invitation request information contains the first direct communication indication information.

[0161] In the second scenario, if at least one of the first invitation request information in step S401 and the first authentication and authorization response information in step S403 contains the first access type indication information, and the first network direct communication capability information indicates that the network supports direct communication between satellites, then the second invitation request information contains the first direct communication indication information.

[0162] In the third scenario, if at least one of the first invitation request information in step S401 and the first authentication and authorization response information in step S403 contains the access type indication information, and the first direct communication authorization result information included in the first authentication and authorization response information indicates that UE1 is allowed to conduct direct voice communication, then the second invitation request information includes the first direct communication indication information.

[0163] It should be noted that if at least one of the first invitation request information in step S401 and the first authentication and authorization response information in step S403 contains the first access type indication information, and the first network direct communication capability information in the first authentication and authorization response information indicates that the network accessed by UE1 does not support direct inter-satellite communication, or the first direct communication authorization result information indicates that UE1 is not allowed to conduct direct voice communication, then the second invitation request information does not contain the first direct communication indication information.

[0164] Furthermore, if at least one of the first invitation request information in step S401 and the first authentication authorization response information in step S403 contains the first access type indication information, and the first network direct communication capability information in the first authentication authorization response information indicates that the network accessed by UE1 does not support inter-satellite direct communication, or the first direct communication authorization result information indicates that UE1 is not allowed to perform the aforementioned direct voice communication, then steps S404-S429 will not be executed, and step S430 will be executed directly, that is, the P-CSCF#1 network element sends the first invitation response information to UE1, which indicates rejection of direct voice communication. At this time, the first invitation response information contains the first direct communication result indication information, which indicates rejection of direct voice communication, or the information itself indicates rejection of direct voice communication.

[0165] It should be noted that, in this embodiment, the preferred solution is that the second invitation request information includes one or more of the first access type indication information and the first network direct communication capability information, but does not include the first direct communication indication information.

[0166] An optional scheme in this embodiment is: the second invitation request information includes the first direct communication indication information, but does not include the first access type indication information and the first network direct communication capability information.

[0167] In addition, if the first invitation request information in step S401 above includes the first media feature support information, the second invitation request information may also include the first media feature support information. The first media feature support information is the same as the first media feature support information in step S401 above, and will not be described in detail here.

[0168] S405: The S-CSCF#1 network element sends the first contract data request information to the UDM network element.

[0169] Accordingly, the UDM network element receives the first subscription data request information. The first subscription data request information requests subscription data from UE1.

[0170] In the first implementation, the first subscription data request information includes first subscription data type information, which indicates that the type of UE1's subscription data is satellite communication subscription data.

[0171] Therefore, the first contract data type information can indicate that the type of contract data is direct communication contract data. Alternatively, if the second invitation request information contains one or more of the first access type indication information, the first network direct communication capability information, and the first direct communication indication information, then the first contract data request information contains the aforementioned first contract data type information.

[0172] It should be noted that when the S-CSCF#1 network element requests the subscription data of UE1 from the UDM network element, it can also request the subscription data of UE2 at the same time. Therefore, the first subscription data request information can include the subscription data type information of UE1 and the subscription data type information of UE2, as described above. In this case, steps S409 and S410 below will not be executed.

[0173] S406: The UDM network element sends the first contract data response information to the S-CSCF#1 network element.

[0174] Correspondingly, the S-CSCF#1 network element receives the first signed data response information.

[0175] In one implementation, the first subscription data request information in step S405 above includes first data type information, and this first data type information indicates that the type of subscription data for UE1 is satellite communication subscription data. Therefore, the first subscription data response information includes first direct communication support information. This first direct communication support information indicates whether UE1 supports or does not support direct voice communication, i.e., allows the first terminal to communicate directly.

[0176] In another implementation, in step S405 above, S-CSCF#1 can also request the subscription data of UE2. Then the first direct communication support information indicates that the first terminal is allowed to communicate directly and the second terminal is allowed to communicate directly, that is, UE1 and UE2 support direct communication.

[0177] It should be noted that steps S405 and S406 are optional.

[0178] S407: S-CSCF#1 network element sends a third invitation request to I-CSCF#2 network element.

[0179] Correspondingly, the I-CSCF#2 network element receives the third invitation request information.

[0180] It should be understood that the P-CSCF#2, S-CSCF#2, and I-CSCF#2 network elements are network elements serving UE2, that is, they belong to the called party network (Terminating Network).

[0181] In one implementation, if the second invitation request information received by S-CSCF#1 in step S404 includes one or more of the first access type indication information, the first network direct communication capability information, the first media feature support information, and the first direct communication indication information, then the third invitation request information sent by S-CSCF#1 network element to I-CSCF#2 network element in step S407 includes the aforementioned first direct communication indication information.

[0182] In the second implementation, if the first direct communication support information in the first contract data response information indicates that UE1 supports direct voice communication in step S406, then the third invitation request information includes the aforementioned first direct communication indication information.

[0183] In the third implementation, if the first direct communication support information in the first contract data response information indicates that UE1 does not support direct voice communication in step S406, then the third invitation request information does not include the aforementioned first direct communication indication information.

[0184] It should be noted that if, in step S406 above, the first direct communication support information in the first subscription data response information indicates that UE1 does not support direct voice communication, then step S407 can be skipped. The S-CSCF#1 network element sends a third invitation response information to the P-CSCF#1 network element, which indicates rejection of direct voice communication. Then, step S429 is executed directly, the same as step S404 above, and will not be described in detail here.

[0185] S408: The I-CSCF#2 network element sends a fourth invitation request to the S-CSCF#2 network element.

[0186] Correspondingly, the S-CSCF#2 network element receives the fourth invitation request information.

[0187] Specifically, the fourth invitation request information includes one or more of the following: first direct communication indication information, first access type indication information, first direct communication support information, first network direct communication capability information, and first media feature support information.

[0188] It should be noted that, in the preferred embodiment, the third invitation request information in step S407 and the fourth invitation request information in step S408 may only contain the first direct communication indication information. In the optional embodiment, the invitation request information in steps S407 and S408 does not contain the first direct communication indication information, but contains one or more of the following: first access type indication information, first direct communication support information, first network direct communication capability information, and first media characteristic support information.

[0189] In the optional scheme of this embodiment, the third invitation request information in step S407 and the fourth invitation request information in step S408 must include the first access type indication information.

[0190] S409: The S-CSCF#2 network element sends a second contract data request message to the UDM network element.

[0191] Correspondingly, the UDM network element receives the second subscription data request information, which requests the subscription data of UE2.

[0192] Optionally, the second subscription data request information includes second subscription data type information, which indicates that the type of UE2 subscription data is satellite communication subscription data.

[0193] In one implementation, the second subscription data type information indicates that the type of UE2 subscription data is second direct communication subscription data.

[0194] In the second implementation, if step S408 includes one or more of the first direct communication indication information, the first access type indication information, the first network direct communication capability information, and the first direct communication indication information, then the second contract data request information includes the aforementioned second contract data type information.

[0195] If UE2's subscription data is queried in step S405, then steps S409 and S410 are not executed.

[0196] S410: The UDM network element sends the second contract data response information to the S-CSCF#1 network element.

[0197] Correspondingly, the S-CSCF#1 network element receives the second contract data response information.

[0198] Optionally, the second contract data response information includes second direct communication support information, which indicates whether UE2 supports or does not support direct voice communication, that is, whether UE2 supports or does not support direct voice communication with another terminal via satellite, i.e., allowing UE2 to communicate directly.

[0199] In the first implementation, if the second subscription data request information contains second subscription data type information, and the second subscription data type information indicates that the type of UE2 subscription data is satellite communication subscription data, then the second subscription data response information contains second direct communication support information.

[0200] It should be noted that steps S409-S410 above are optional steps.

[0201] S411: The S-CSCF#2 network element sends the fifth invitation request information to the P-CSCF#2 network element.

[0202] Correspondingly, the P-CSCF#2 network element receives the fifth invitation request information.

[0203] Optionally, the fifth invitation request information includes second direct communication indication information, which has the same function as the first direct communication indication information in step S402.

[0204] In one implementation, if the fourth invitation request information in step S408 includes one or more of the first access type indication information, the first direct communication support indication information, the first network direct communication capability information, and the first direct communication indication information, then the fifth invitation request information includes the aforementioned second direct communication indication information.

[0205] In the second implementation, if the second direct communication support information in step S410 indicates that UE2 supports direct voice communication, then the fifth invitation request information includes the second direct communication indication information.

[0206] It should be noted that in the second implementation, if the second direct communication support information in step S410 indicates that UE2 does not support direct voice communication, then the fifth invitation request information does not include the second direct communication indication information. Alternatively, step S411 can be skipped. The S-CSCF#2 network element sends a fourth invitation response information to the I-CSCF#2 network element, which indicates rejection of direct voice communication. The I-CSCF#2 network element sends a third invitation response information to the S-CSCF#1 network element, which indicates rejection of direct voice communication. The S-CSCF#1 network element sends a second invitation response information to the P-CSCF#1 network element, which indicates rejection of direct voice communication. After this step, step S429 is executed directly. For details, please refer to step S404 above, which will not be elaborated here.

[0207] S412: The P-CSCF#2 network element sends a second authentication and authorization request to the PCF network element.

[0208] Accordingly, the PCF network element receives the second authentication and authorization request information.

[0209] Optionally, the second authentication and authorization request information may include the aforementioned second direct communication instruction information.

[0210] In the first implementation, if the fifth invitation request information in step S411 contains the second direct communication indication information, then the second authentication and authorization request information contains the aforementioned second direct communication indication information.

[0211] It should be noted that if the first network direct communication capability information is not involved in the above steps S402-S403, then the second authentication and authorization request information includes the second network direct communication capability request information. Since the networks accessed by UE1 and UE2 during direct voice communication can belong to the same network, the first network direct communication capability information is the same as the second network direct communication capability information.

[0212] It should be noted that the PCF in steps S402-S403 and the PCF in steps S412-S413 may not be the same PCF. The PCF in steps S402-S403 is the PCF corresponding to the session of UE1 used to transmit the data of the IMS service, and the PCF in steps S412-S413 is the PCF corresponding to the session of UE2 used to transmit the data of the IMS service.

[0213] S413: The PCF network element sends a second authentication and authorization response to the P-CSCF#2 network element.

[0214] Correspondingly, the P-CSCF#2 network element receives the second authentication and authorization response information.

[0215] Optionally, the second authentication authorization response information includes second access type indication information. Since UE1 accesses the network via satellite and UE2 accesses the network via satellite, the types of satellite access for UE1 and UE2 can be the same. That is, the second access type indication information has the same function as the first access type indication information in step S401 above, which will not be repeated here.

[0216] Optionally, if steps S402-S403 do not involve the first network direct communication capability information, then the second authentication and authorization response information includes the second network direct communication capability information. See step S403 above for details. It should be understood that since UE1 and UE2 can access the same network when they conduct direct voice communication, the second network direct communication capability information is the same as the first network direct communication capability information.

[0217] S414: P-CSCF#2 network element sends the sixth invitation request information to UE#2 network element.

[0218] Correspondingly, UE#2 network element receives the sixth invitation request information.

[0219] In one implementation, if the fifth invitation request information in step S411 contains the second direct communication indication information, and the second access type indication information in the second authentication and authorization response information in step S413 indicates that UE2 does not access via satellite, then step S414 is no longer executed. The P-CSCF#2 network element sends the fifth invitation response information to the S-CSCF#2 network element, which indicates rejection of direct voice communication. Subsequently, the S-CSCF#2 network element executes the rejection process similar to the one in step S411 where the S-CSCF#2 network element returns the invitation response information. This will not be elaborated further here.

[0220] S415: UE2 sends the sixth invitation response information to the P-CSCF#2 network element.

[0221] Correspondingly, the P-CSCF#2 network element receives the sixth invitation response information.

[0222] Optionally, the sixth invitation response information may include second access type indication information, which indicates that UE2 accesses the network via satellite, specifically the same as the first access type indication information in step S401. It should be noted that the second access type indication information may also indicate other access types, such as indicating that UE2 does not access the network via satellite.

[0223] This application does not limit the other access types specifically indicated. Unless otherwise specified, the second access type indication information indicates that UE2 accesses the network via satellite.

[0224] Optionally, the sixth invitation response information may also include second media feature support information, which indicates that UE2 supports media features for direct voice communication. It should be noted that the second media feature support information may also indicate that UE2 does not support media features for direct voice communication; unless otherwise specified, the second media feature support information indicates that UE2 supports media features for direct voice communication. The media features supported by UE2 may include voice data encoding / decoding methods supported by UE2 for the aforementioned direct voice communication.

[0225] It should be noted that the second direct communication support information in step S410, the second access type indication information in step S413, the second access type indication information in step S415, and the second media characteristic support information in step S415 are all for UE2. Since UE1 and UE2 access the same network when conducting direct voice communication, the first network direct communication capability information and the second network direct communication capability information are the same.

[0226] S416: P-CSCF#2 network element sends the fifth invitation response information to S-CSCF#2 network element.

[0227] Correspondingly, the S-CSCF#2 network element receives the fifth invitation response information.

[0228] Optionally, the fifth invitation response information may include second access type information. This second access type information refers to the type of satellite accessed by UE2.

[0229] In the first implementation, if at least one of the second authentication and authorization response information in step S413 and the sixth invitation response information in step S415 contains the aforementioned second access type indication information, then the fifth invitation response information contains the second access type information.

[0230] Optionally, the fifth invitation response information may include information supporting the second media feature.

[0231] In the second implementation, if at least one of the second authentication authorization response information in step S413 and the sixth invitation response information in step S415 contains the aforementioned second access type indication information, and the second access type indication information indicates that UE2 does not access via satellite, then the fifth invitation response information indicates rejection of direct voice communication.

[0232] S417: The S-CSCF#2 network element sends the fourth invitation response information to the I-CSCF#2 network element.

[0233] Correspondingly, the I-CSCF#2 network element receives the fourth invitation response information.

[0234] Optionally, the fourth invitation response information may include one or more of the following: second access type information, second media feature support information, second direct communication support information, and second network direct communication capability information (first network direct communication capability information).

[0235] In the first implementation, if step S408 includes first direct communication indication information, which corresponds to the preferred scheme described in step S408, then the fourth invitation response information includes one or more of the second access type information, second media feature support information, second direct communication support information, and second network direct communication capability information (first network direct communication capability information). In this scheme, the second access type information is mandatory.

[0236] In the second implementation, the fourth invitation response information includes a second direct communication result indication information, which instructs UE2 to accept or reject direct voice communication. Therefore, the fourth invitation response information indicates whether to accept or reject direct voice communication. Alternatively, the fourth invitation response information itself may indicate whether to accept or reject direct voice communication.

[0237] In the third implementation, if step S408 includes one or more of the following: first access type indication information, first direct communication support information, first network direct communication capability information, and first media characteristic support information, corresponding to the optional scheme described in step S408, then the fourth invitation response information includes second direct communication result indication information. If the following conditions are simultaneously met, the S-CSCF#2 network element determines that UE1 and UE2 will establish direct communication. Specifically, the conditions can be:

[0238] 1) The first access type indication information of UE1 indicates that UE1 accesses the network via satellite, and the second access type information of UE2 indicates that UE2 accesses the network via satellite;

[0239] 2) If the first media feature support information of UE1 and the second media feature support information of UE2 are received, and the media features supported by UE1 and the media features supported by UE2 both support media features for direct voice communication, in one implementation, the media features supported by UE1 and the media features supported by UE2 need to match.

[0240] 3) If the first network direct communication capability information and the second network direct communication capability information (the first network direct communication capability information is the same as the second network direct communication capability information) are received, it indicates that the network accessed by UE1 and UE2 supports direct inter-satellite communication;

[0241] 4) If the first direct communication support information of UE1 and the second direct communication support information of UE2 are received, and the first direct communication support information of UE1 and the second direct communication support information of UE2 indicate that both UE1 and UE2 support direct voice communication, that is, UE1 is allowed to communicate directly and UE2 is allowed to communicate directly.

[0242] If any of the above conditions are not met, the S-CSCF#2 network element will refuse direct voice communication.

[0243] It should be noted that there is a possible scenario where only partial information is obtained, and not all conditions need to be met. In this case, the S-CSCF#2 network element determines that UE1 and UE2 should establish direct communication. If only the first access type indication information of UE1 and the second access type information of UE2 are available, then only condition 1 needs to be met.

[0244] S418: The I-CSCF#2 network element sends a third invitation response message to the S-CSCF#1 network element.

[0245] Correspondingly, the S-CSCF#1 network element receives the third invitation response information.

[0246] Specifically, the content of the third invitation response information is the same as that in step S417, and will not be described in detail here.

[0247] S419: The S-CSCF#1 network element determines to accept direct voice communication, that is, to establish direct communication between UE1 and UE2.

[0248] In the first implementation, the S-CSCF#1 network element receives the first network direct communication capability information (the second network direct communication capability information), as well as any one or more of the access type indication information, direct communication support information, and media characteristic support information of UE1 and UE2; if the four conditions described in step S417 are met simultaneously, the S-CSCF#1 network element determines to accept direct voice communication; otherwise, the S-CSCF#1 network element determines to reject direct voice communication.

[0249] It should be understood that the access type indication information for UE1 and UE2 is the first access type indication information and the second access type indication information; the direct communication support information for UE1 and UE2 is the first direct communication support information and the second direct communication support information; and the media characteristic support information for UE1 and UE2 is the first media characteristic support information and the second media characteristic support information.

[0250] The method for determining S-CSCF#1 is the same as step S417, and will not be repeated here.

[0251] In the second implementation, the third invitation response information received by the S-CSCF#1 network element indicates whether to accept or reject direct voice communication.

[0252] It should be noted that the above can be referred to in cases where direct voice communication is refused, and will not be elaborated on here.

[0253] In this embodiment, Figure 4A and Figure 4BThe processes belonging to the same embodiment, the above steps S401-S409 refer to Figure 4A The following steps are referenced in S420-S430. Figure 4B .

[0254] S420: S-CSCF#1 network element sends a second invitation response message to P-CSCF#1 network element.

[0255] Correspondingly, the P-CSCF#1 network element receives the second invitation response information.

[0256] In the first implementation, the second invitation response information includes QoS requirement information for direct voice communication, wherein the QoS requirement information refers to information such as QoS identifiers or parameters.

[0257] In the second implementation, the second invitation response information indicates acceptance of direct voice communication, and the specific indication method is the same as in step S417.

[0258] S421: P-CSCF#1 network element sends direct communication establishment information to PCF network element.

[0259] Correspondingly, the PCF network element receives the direct communication establishment information.

[0260] Optionally, the direct communication establishment information includes information about UE1 and UE2. Specifically, the direct communication establishment information includes the IP address information of UE1 and UE2, or it includes the identification information of UE1 and UE2, where the identification information can be a Generic Public Subscription Identifier (GPSI). It should be noted that, in some places mentioned in this application, the identification information may also indicate address information.

[0261] Optionally, the direct communication establishment information includes direct communication establishment indication information, which indicates that direct voice communication is established between UE1 and UE2.

[0262] Optionally, the direct communication establishment information may also include QoS requirement information for direct voice communication.

[0263] It should be noted that after step S421, the PCF network element also needs to send a response message to the P-CSCF#2 network element to confirm receipt. To simplify this step, Figure 4B The process of the PCF network element sending response information to the P-CSCF#2 network element is not shown separately. Instead, double arrows are used to represent the interaction between the PCF network element and the P-CSCF#2 network element. Step S422 is the same and will not be described again.

[0264] S422: The PCF network element sends a direct communication establishment message to the SMF network element.

[0265] Correspondingly, the SMF network element receives the direct communication establishment information.

[0266] Optionally, the direct communication establishment information includes information about UE1 and UE2. This is the same as step S421 above, and can be referred to step S421 above.

[0267] The PCF network element receives information from UE1 and UE2. Based on the information from UE1 and UE2, the PCF network element determines the PDU session identifier of UE1 and the PDU session identifier of UE2, and includes the identifier information in the direct communication establishment information.

[0268] Optionally, the direct communication establishment information may include the aforementioned direct communication establishment instruction information.

[0269] Optionally, the direct communication establishment information may include QoS information for direct voice communication. This QoS information is the same as the QoS requirement information in step S421, or the PCF network element determines the QoS information based on the QoS requirement information in step S421, for example, it may be a change in form.

[0270] It should be noted that the direct communication establishment information in steps S421 and S422 can be the same or different information, and no specific limitation is made here.

[0271] S423: SMF network element allocates tunnel information for direct voice communication in S-UPF1 and S-UPF2 network elements.

[0272] The S-UPF1 network element is the user plane network element used by UE1 for direct voice communication PDU sessions, and the S-UPF2 network element is the user plane network element used by UE2 for direct voice communication PDU sessions.

[0273] It should be understood that in this application, the S-UPF1 network element and the S-UPF2 network element can be located on two different satellites. The tunnel refers to the tunnel between the S-UPF1 network element and the S-UPF2 network element, and the tunnel is used to transmit voice data.

[0274] In the first implementation, the SMF network element receives information from UE1 and UE2. Based on the information from UE1 and UE2, the SMF network element determines the identifier of the PDU session of UE1 and the identifier of the PDU session of UE2 used for direct voice communication. The SMF network element allocates tunnel information for the PDU sessions of UE1 and UE2, which are the tunnel information for direct voice communication in S-UPF1 and S-UPF2, respectively.

[0275] In the second implementation, the SMF network element receives the identifiers of the PDU sessions of UE1 and UE2 for direct voice communication, and the SMF network element allocates tunnel information for the PDU sessions of UE1 and UE2.

[0276] In the third implementation, when the SMF network element receives the direct communication establishment indication information, it allocates tunnel information for the PDU session of UE1 and UE2.

[0277] S424: The SMF network element sends an N4 session request message to the S-UPF1 network element.

[0278] Correspondingly, the S-UPF1 network element receives the N4 session request information.

[0279] Specifically, the N4 session request information requests the configuration of tunnel information for the PDU session used for direct voice communication. The N4 session request information includes QoS information for direct voice communication and tunnel information for direct voice communication in S-UPF1 and S-UPF2.

[0280] S425: Establish an internal tunnel between gNB1 and S-UPF1 network elements.

[0281] Specifically, after the S-UPF1 network element updates the tunnel information, gNB1 needs to update the corresponding tunnel information in order to establish a tunnel between gNB1 and the S-UPF1 network element.

[0282] It should be noted that this application does not limit how the tunnel is established between gNB1 and S-UPF1 network elements. For example, the tunnel can be established through interaction between SMF network elements and gNB1, or through interaction between gNB1 and S-UPF1 network elements. Step S425 can also be performed after step S426.

[0283] S426: The S-UPF1 network element sends an N4 session response message to the SMF network element. This N4 session response message is used to confirm that the tunnel has been configured.

[0284] S427: The SMF network element sends an N4 session request message to the S-UPF2 network element.

[0285] S428: Establish an internal tunnel between gNB2 and S-UPF2 network elements.

[0286] S429: The S-UPF2 network element sends an N4 session response message to the SMF network element. This N4 session response message is used to confirm that the tunnel has been configured.

[0287] It should be noted that steps S427-S429 are similar to steps S424-S426, the difference being that in steps S427-S429, the S-UPF1 network element is changed to the S-UPF2 network element, and gNB1 is changed to gNB2. This application does not specify the order in which steps S424-S426 and steps S427-S429 are performed.

[0288] S430: P-CSCF network element #1 sends the first invitation response information to UE1.

[0289] Accordingly, the UE1 receives the first invitation response information, which indicates acceptance of direct voice communication.

[0290] It should be noted that the first invitation response message can also indicate the rejection of direct voice communication.

[0291] In summary, Figures 4A-4B The illustrated embodiment describes a scenario with multiple IM CNs where the CSCF serving UE1 and the CSCF serving UE2 are different. The first terminal can be determined by the corresponding CSCF based on the access type information, subscription information, network support capability information, and media characteristic information supported by the first and second terminals. Then, the SMF network element establishes a transmission path for the direct voice communication between the first and second terminals, allowing them to communicate directly through the established transmission path. This avoids the transmission of voice data between the first and second terminals via the ground, thus preventing a longer voice communication duration.

[0292] Based on the communication method provided in the above embodiments, the following detailed description of the method of this application is provided in conjunction with a specific embodiment. This embodiment mainly enables direct voice communication between terminals via satellite in a single IM CN scenario. In this embodiment, UE1 and UE2 can access the network through a corresponding satellite, that is, UE1 can access the network through a first satellite, and UE2 can access the network through a second satellite. Each satellite includes a base station and a UPF network element, and UE1 and UE2 are served by the same Call Control Function (CSCF) network element, which includes P-CSCF, I-CSCF, and S-CSCF network elements. (Reference) Figure 5 As shown, the specific implementation process of this embodiment is as follows:

[0293] S501: Terminal UE1 sends a first invitation request to the P-CSCF#1 network element, which requests communication with the second terminal UE2.

[0294] Step S501 can be referred to step S401 above, and will not be described in detail here.

[0295] S502: P-CSCF#1 network element initiates the first authentication and authorization request to PCF network element.

[0296] Step S502 can be referred to step S402 above, and will not be described in detail here.

[0297] S503: The PCF network element sends the first authentication and authorization response information to the P-CSCF#1 network element.

[0298] Step S503 can be referred to step S403 above, and will not be described in detail here.

[0299] S504: P-CSCF#1 network element sends a second invitation request to S-CSCF#1 network element.

[0300] Step S504 can be referred to step S404 above, and will not be described in detail here.

[0301] S505: The S-CSCF#1 network element sends a subscription data request message to the UDM network element.

[0302] Step S505 can be referred to step S405 above, and will not be described in detail here.

[0303] S506: The UDM network element sends a subscription data response message to the S-CSCF#1 network element.

[0304] Step S506 can be referred to step S406 above, and will not be described in detail here.

[0305] It should be noted that steps S501-S506 above are largely the same as steps S401-S406 above, with the main differences including: in Figures 4A-4B In the multi-IM CN scenario, the direct communication support information for UE1 becomes the direct communication support information between UE1 and UE2 in the single-IM CN scenario. That is, in step S505, the subscription data request information requests subscription data from UE1 and UE2.

[0306] S507: S-CSCF#1 network element sends a third invitation request to UE#2 network element.

[0307] It should be noted that if the access type indication information in step S501 or step S503 indicates that UE1 accesses the network via satellite, and the network direct communication capability information indicates that the network does not support direct communication between satellites, then steps S507-S519 will not be executed, and step S520 will be executed directly below. Alternatively,

[0308] If the access type indication information in step S501 or step S503 indicates that UE1 accesses the network via satellite, and the direct communication support information of UE1 indicates that UE1 does not support direct voice communication or the direct communication support information of UE2 indicates that UE2 does not support direct voice communication, then steps S507-S519 will not be executed, and step S520 will be executed directly.

[0309] S508: UE2 sends a third invitation response message to the S-CSCF#1 network element.

[0310] Step S508 can be referred to step S415 above, and will not be described in detail here.

[0311] S509: The S-CSCF#1 network element is confirmed to accept direct voice communication.

[0312] Step S509 can be referred to step S419 above, and will not be described in detail here.

[0313] S510: The S-CSCF#1 network element sends a second invitation response message to the P-CSCF#1 network element.

[0314] Step S509 can be referred to step S420 above, and will not be described in detail here.

[0315] S511: P-CSCF#1 network element sends direct communication establishment information to PCF network element.

[0316] Step S511 can be referred to step S421 above, and will not be described in detail here.

[0317] S512: The PCF network element sends a direct communication establishment message to the SMF network element.

[0318] Step S512 can be referred to step S422 above, and will not be described in detail here.

[0319] S513: SMF network element allocates tunnel information for direct voice communication in S-UPF1 and S-UPF2 network elements.

[0320] Step S513 can be referred to step S423 above, and will not be described in detail here.

[0321] S514: The SMF network element sends an N4 session request message to the S-UPF1 network element.

[0322] Step S514 can be referred to step S424 above, and will not be described in detail here.

[0323] S515: Establish an internal tunnel between gNB1 and S-UPF1 network elements.

[0324] Step S515 can be referred to step S425 above, and will not be described in detail here.

[0325] S516: The S-UPF1 network element sends an N4 session response message to the SMF network element. This N4 session response message is used to confirm that the tunnel has been configured.

[0326] Step S516 can be referred to step S426 above, and will not be described in detail here.

[0327] S517: The SMF network element sends an N4 session request message to the S-UPF2 network element.

[0328] Step S517 can be referred to step S427 above, and will not be described in detail here.

[0329] S518: Establish an internal tunnel between gNB2 and S-UPF2 network elements.

[0330] Step S518 can be referred to step S428 above, and will not be described in detail here.

[0331] S519: The S-UPF2 network element sends an N4 session response message to the SMF network element. This N4 session response message is used to confirm that the tunnel has been configured.

[0332] Step S519 can be referred to step S429 above, and will not be described in detail here.

[0333] S520: P-CSCF network element #1 sends the first invitation response information to UE1.

[0334] Step S520 can be referred to step S430 above, and will not be described in detail here.

[0335] It should be noted that the above steps S509-S520 are roughly the same as steps S419-S430 in the multi-IM CN scenario process. The main difference is that in step S519, the S-CSCF#1 network element does not receive an invitation response message indicating whether to accept or reject direct voice communication.

[0336] In summary, Figure 5The illustrated embodiment describes a scenario with a single IM CN. The CSCF serving UE1 is the same as that serving UE2. The first terminal can determine whether to establish direct voice communication between the first terminal and the second terminal based on the access type information, subscription information, network support capability information, and supported media characteristics information of the first terminal and the second terminal. Then, the SMF network element establishes a transmission path for direct voice communication between the first terminal and the second terminal, so that the first terminal and the second terminal can conduct direct voice communication through the established transmission path. This avoids the transmission of voice data between the first terminal and the second terminal through the ground, thereby reducing the duration of voice communication between the first terminal and the second terminal and greatly improving the user experience.

[0337] Based on the same technical concept, embodiments of this application provide a communication device. This device may include modules or units corresponding to the methods / operations / steps / actions described by the call session control function network element in the first method embodiment described above. These modules or units may be hardware circuits, software, or a combination of hardware circuits and software. The device may have the following characteristics: Figure 6 The structure shown.

[0338] like Figure 6 As shown, the communication device 600 may include a receiving unit 601, a processing unit 602, and a transmitting unit 603. The following is a detailed description of each unit.

[0339] The receiving unit 601 receives a first invitation request from a first terminal, the first invitation request requesting communication with a second terminal; the receiving unit 601 is also configured to acquire first access information and second access information, the first access information indicating that the first terminal accesses the network via satellite, and the second access information indicating that the second terminal accesses the network via satellite; the processing unit 602 is configured to determine, based on the first access information and the second access information, that direct communication be established between the first terminal and the second terminal; the direct communication refers to the direct transmission of Internet Protocol Multimedia Subsystem (IMS) service data between the first terminal and the second terminal between a first satellite in the network accessed by the first terminal and a second satellite in the network accessed by the second terminal; the sending unit 603 sends a first request to a first network element, the first request indicating direct communication between the first terminal and the second terminal.

[0340] In one possible implementation, when the receiving unit 601 acquires the first access information, it may specifically be used to: acquire the first access information from the first terminal or the policy control function network element corresponding to the session of the first terminal, wherein the session of the first terminal is used to transmit the data of the IMS service.

[0341] In one possible implementation, the receiving unit, when acquiring the second access information, may specifically be used to: acquire the second access information from the second terminal or the policy control function network element corresponding to the session of the second terminal or the call session control function network element corresponding to the second terminal, wherein the session of the second terminal is used to transmit the data of the IMS service.

[0342] In one possible implementation, the receiving unit 601 can also be used to: before the processing unit 602 determines, based on the first access information and the second access information, that direct communication should be established between the first terminal and the second terminal,

[0343] Obtain first network pass-through capability information, which indicates that the first network supports the direct communication, and the first terminal and the second terminal access the network through the first network.

[0344] In one possible implementation, the receiving unit 601 may further be configured to: before the processing unit 602 determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal, further comprising: receiving first direct communication subscription information and second direct communication subscription information, wherein the first direct communication subscription information indicates that the first terminal is allowed to communicate directly, and the second direct communication subscription information indicates that the second terminal is allowed to communicate directly.

[0345] In one possible implementation, the receiving unit 601 may further be used to: before the processing unit 602 determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal, acquire first media feature support information and second media feature support information, wherein the first media feature support information indicates the media features of the first terminal for the IMS service, and the second media feature support information indicates the media features of the second terminal for the IMS service.

[0346] In one possible implementation, the first invitation request information includes direct communication request indication information, which indicates that the first terminal expects to conduct the direct communication with the second terminal.

[0347] In one possible implementation, the first request information includes the identification information of the first terminal and the identification information of the second terminal.

[0348] In one possible implementation, the first request information includes Quality of Service (QoS) information for the direct communication.

[0349] In one possible implementation, the sending unit 603 can also be used to: send a first invitation response information to the first terminal, wherein the first invitation response information indicates acceptance of the direct communication between the first terminal and the second terminal.

[0350] Based on the same inventive concept, embodiments of this application also provide a communication device, which performs... Figure 3A , Figure 3B , Figures 4A-4B as well as Figure 5 The steps executed by the call session control function network element in the method provided in the corresponding embodiment may be the same as those performed by the network element. Figure 6 The communication device 600 shown is the same equipment. See also Figure 7 As shown, the communication device 700 includes a transceiver 701, a processor 702, and a memory 703. The transceiver 701, processor 702, and memory 703 are connected via a bus 704 to enable data exchange.

[0351] It should be understood that the transceiver 701 in the communication device 700 includes the functions of the transmitting unit 601 and the receiving unit 603 in the communication device 600 described above. The transceiver 701 supports the transmission and reception of information between the communication device 700 and network elements in the core network of the above embodiments, as well as terminals. The core network elements may include policy control network elements, unified data management network elements, etc. The memory 703 stores the program code and data of the communication device 700. The processor 702 calls the program code and data stored in the memory 703 to execute... Figures 3A-3B , Figures 4A-4B as well as Figure 5 The method shown involves the processing of call session control function network elements and / or other processes used in the technology described in this application.

[0352] In addition, the communication device 700 may also include other interfaces, such as fiber optic link interfaces, Ethernet interfaces, microwave link interfaces, copper wire interfaces, etc., to enable the communication device 700 to interact with other devices (e.g., access network equipment and UPF on satellites, core network elements on the ground).

[0353] Optionally, the processor 702 can be a central processing unit, ASIC, FPGA, or CPLD.

[0354] It should be noted that, Figure 7 The communication device 700 shown includes only one transceiver 701, one processor 702, and one memory 703. In actual implementation, the number of transceivers 701, processors 702, and memory 703 can be one or more.

[0355] Based on the same concept as the above-described method embodiments, this application also provides a computer-readable storage medium storing some instructions. When these instructions are invoked and executed by a computer, the computer can perform the methods involved in any possible design of the above-described method embodiments. In this application, the computer-readable storage medium is not limited; for example, it can be RAM (random-access memory), ROM (read-only memory), etc.

[0356] Based on the same concept as the above method embodiments, this application also provides a computer program product that, when executed by a computer, can perform the methods involved in the method embodiments and any possible designs of the above method embodiments.

[0357] Based on the same concept as the above method embodiments, this application also provides a chip, which may include a processor and an interface circuit, for performing the methods involved in any possible implementation of the above method embodiments, wherein "coupling" means that two components are directly or indirectly combined with each other, and such combination may be fixed or movable, and such combination may allow fluid, electricity, electrical signals or other types of signals to communicate between the two components.

[0358] It should be noted that the "at least one" in the embodiments of this application includes one or more; wherein, "more" means two or more. Furthermore, it should be understood that in the description of this application, terms such as "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance, nor as indicating or implying order.

[0359] The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “the,” “the,” “the,” and “this” are intended to also include expressions such as “one or more,” unless the context clearly indicates otherwise. It should also be understood that in the embodiments of this application, “one or more” means one or more (including two); “and / or” describes the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character “ / ” generally indicates that the preceding and following related objects are in an “or” relationship.

[0360] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0361] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0362] Through the above description of the embodiments, those skilled in the art will clearly understand that the embodiments of this application can be implemented in hardware, firmware, or a combination thereof. When implemented in software, the above functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium accessible to a computer. For example, but not limited to, computer-readable media can include RAM, ROM, electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, magnetic disk storage media, or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible to a computer. Furthermore, any connection can suitably be a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. As used in embodiments of this application, disks and discs include compact discs (CDs), laser discs, optical discs, digital video discs (DVDs), floppy disks, and Blu-ray discs, wherein disks typically magnetically copy data, while discs optically copy data using lasers. The combinations above should also be included within the scope of protection for computer-readable media.

[0363] In summary, the above descriptions are merely embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made based on the disclosure of this application should be included within the scope of protection of this application.

Claims

1. A communication method, characterized in that, include: The call session control function network element corresponding to the first terminal receives a first invitation request information from the first terminal, and the first invitation request information requests communication with the second terminal. The call session control function network element corresponding to the first terminal obtains the first access information and the second access information from the policy control function network element corresponding to the session of the first terminal and the call session control function network element corresponding to the second terminal, respectively. The session of the first terminal is used to transmit data of Internet Protocol Multimedia Subsystem (IMS) service. The first access information indicates that the first terminal accesses the network via satellite, and the second access information indicates that the second terminal accesses the network via satellite. The call session control function network element corresponding to the first terminal determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal; The direct communication refers to the direct transmission of IMS service data between the first terminal and the second terminal between the first satellite of the first terminal access network and the second satellite of the second terminal access network. The call session control function network element corresponding to the first terminal sends a first request message to the first network element, and the first request message indicates that the first terminal and the second terminal communicate directly.

2. The method according to claim 1, characterized in that, Before the call session control function network element corresponding to the first terminal determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal, it further includes: The call session control function network element corresponding to the first terminal obtains the first network pass-through capability information. The first network pass-through capability information indicates that the first network supports the direct communication, and the first terminal and the second terminal access each other through the first network.

3. The method according to claim 1, characterized in that, Before the call session control function network element corresponding to the first terminal determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal, it further includes: The call session control function network element corresponding to the first terminal receives the first direct communication subscription information and the second direct communication subscription information. The first direct communication subscription information indicates that the first terminal is allowed to communicate directly, and the second direct communication subscription information indicates that the second terminal is allowed to communicate directly.

4. The method according to claim 1, characterized in that, Before the call session control function network element corresponding to the first terminal determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal, it further includes: The call session control function network element corresponding to the first terminal obtains first media feature support information and second media feature support information. The first media feature support information indicates the media features of the first terminal for the IMS service, and the second media feature support information indicates the media features of the second terminal for the IMS service.

5. The method according to claim 1, characterized in that, The first invitation request information includes direct communication request indication information, which indicates that the first terminal expects to conduct the direct communication with the second terminal.

6. The method according to any one of claims 1-4, characterized in that, The first request information includes the identification information of the first terminal and the identification information of the second terminal.

7. The method according to any one of claims 1-4, characterized in that, The first request information includes Quality of Service (QoS) information for the direct communication.

8. The method according to any one of claims 1-7, characterized in that, The method further includes: The call session control function network element corresponding to the first terminal sends a first invitation response information to the first terminal, the first invitation response information indicating acceptance of the direct communication between the first terminal and the second terminal.

9. The method according to any one of claims 1-8, characterized in that, The first network element is the Session Management Function (SMF) network element.

10. A call session control function network element, characterized in that, The call session control function network element corresponds to the first terminal, and the call session control function network element includes: a receiving unit, a processing unit, and a sending unit; The receiving unit is configured to receive a first invitation request information from the first terminal, wherein the first invitation request information requests communication with the second terminal; The receiving unit is further configured to obtain first access information and second access information from the policy control function network element corresponding to the session of the first terminal and the call session control function network element corresponding to the second terminal, respectively. The session of the first terminal is used to transmit data of Internet Protocol Multimedia Subsystem (IMS) service. The first access information indicates that the first terminal accesses the network via satellite, and the second access information indicates that the second terminal accesses the network via satellite. The processing unit is configured to determine, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal; the direct communication refers to the direct transmission of IMS service data between the first terminal and the second terminal between a first satellite in the first terminal access network and a second satellite in the second terminal access network. The sending unit is used to send a first request information to the first network element, wherein the first request information indicates direct communication between the first terminal and the second terminal.

11. The call session control function network element according to claim 10, characterized in that, The receiving unit is further configured to: before the processing unit determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal, obtain first network pass-through capability information, wherein the first network pass-through capability information indicates that the first network supports the direct communication, and the first terminal and the second terminal access the network through the first network.

12. The call session control function network element according to claim 10, characterized in that, The receiving unit is further configured to: receive first direct communication subscription information and second direct communication subscription information before the processing unit determines, based on the first access information and the second access information, that direct communication between the first terminal and the second terminal is established, wherein the first direct communication subscription information indicates that direct communication between the first terminal is permitted and the second direct communication subscription information indicates that direct communication between the second terminal is permitted.

13. The call session control function network element according to claim 10, characterized in that, The receiving unit is further configured to: before the processing unit determines, based on the first access information and the second access information, to establish direct communication between the first terminal and the second terminal, acquire first media feature support information and second media feature support information, wherein the first media feature support information indicates the media features of the first terminal for the IMS service, and the second media feature support information indicates the media features of the second terminal for the IMS service.

14. The call session control function network element according to claim 10, characterized in that, The first invitation request information includes direct communication request indication information, which indicates that the first terminal expects to conduct the direct communication with the second terminal.

15. The call session control function network element according to any one of claims 10-13, characterized in that, The first request information includes the identification information of the first terminal and the identification information of the second terminal.

16. The call session control function network element according to any one of claims 10-13, characterized in that, The first request information includes Quality of Service (QoS) information for the direct communication.

17. The call session control function network element according to any one of claims 10-16, characterized in that, The sending unit is further configured to: send a first invitation response information to the first terminal, wherein the first invitation response information indicates acceptance of the direct communication between the first terminal and the second terminal.

18. The call session control function network element according to any one of claims 10-17, characterized in that, The first network element is the Session Management Function (SMF) network element.

19. A non-volatile computer-readable storage medium, characterized in that, A computer program is stored, which is loaded by a processor to execute the method as described in any one of claims 1-9.

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