CN115842578A

CN115842578A - Communication method and device

Info

Publication number: CN115842578A
Application number: CN202111101804.7A
Authority: CN
Inventors: 宗在峰; 张成晨; 吴凤伟; 屈琴
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-09-18
Filing date: 2021-09-18
Publication date: 2023-03-24
Also published as: WO2023040567A1

Abstract

A method and apparatus for communication, the method comprising: a call session control function network element receives first invitation request information of a first terminal, and then acquires first access information of the first terminal and second access information of a second terminal, wherein the first access information indicates that the first terminal is accessed through a satellite, and the second access information indicates that the second terminal is accessed through the satellite; and finally, the call session control function network element sends first request information to the first network element to indicate that the direct communication is established for the first terminal and the second terminal. The method can ensure that the IMS service data transmitted by the first terminal and the second terminal does not pass through the ground, thereby reducing the time length of IMS service between the first terminal and the second terminal and improving the user experience to a greater extent.

Description

Communication method and device

Technical Field

The present application relates to the field of communications technologies, and in particular, to a communication method and apparatus.

Background

Future 5G and its evolution networks need to not only meet multiple service requirements, but also provide wider service coverage. The satellite plays an important role in the field of wireless communication due to the characteristics of long communication distance, wide coverage range, flexible networking, no limitation of geographical environment conditions, no limitation of ground equipment conditions and the like.

Common services of a terminal device include voice communication, and an IP Multimedia Subsystem (IMS) can provide services such as voice, video, and information for a user. In a satellite communication scenario, access network equipment or User Plane Function (UPF) network elements on the ground may be deployed on a satellite, but an IMS system may be located on the ground due to limited loading capability of the satellite. When two terminal devices need to access a network through a satellite to perform voice communication service, voice data of one terminal device needs to be transmitted to an IMS system on the ground through a user plane function network element on the satellite, then transmitted to a user plane function network element on another satellite through the IMS system on the ground, and finally transmitted to another terminal device. However, the time delay of the transmission between the satellite and the ground is large, which causes the time delay of the voice communication between the two terminal devices to be large. Therefore, it is desirable to provide a communication method that can reduce the time delay generated when the terminal device performs the service through the satellite.

Disclosure of Invention

A communication method and device can be applied to satellite communication to reduce time delay generated by service between terminal devices.

In a first aspect, the present application provides a communication method, which may be executed by a call session control function network element, or may be executed by a chip corresponding to the network element, which is not limited to this. The method specifically comprises the following steps: a call session control function network element receives first invitation request information of a first terminal, and the first invitation request information requests to communicate with a second terminal; the call session control function network element acquires first access information and second access information, wherein the first access information indicates that the first terminal accesses a network through a satellite, and the second access information indicates that the second terminal accesses the network through the satellite; the call session control function network element determines to establish direct communication between the first terminal and the second terminal according to the first access information and the second access information; the direct communication means that data of an internet protocol multimedia subsystem (IMS) service between the first terminal and the second terminal is directly transmitted between a first satellite of the first terminal access network and a second satellite of the second terminal access network; the call session control function network element sends first request information to a first network element, wherein the first request information indicates that the first terminal and the second terminal are in direct communication.

The method comprises the steps that after a call session control function network element receives an invitation request of a first terminal, first access information and second access information are obtained, the first access information indicates that the first terminal accesses a network through a satellite, the second access information indicates that the second terminal accesses the network through the satellite, and the call session control function network element can determine that direct communication can be established between the first terminal and the second terminal according to the first access information and the second access information and sends first request information to the first network element to indicate that the first terminal and the second terminal directly communicate. When the direct communication is the IMS service between the first terminal and the second terminal, the IMS service data can be transmitted through the satellite without passing through the ground, so that the time length of the IMS service between the first terminal and the second terminal can be reduced, and the user experience can be improved to a greater extent.

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

Through the embodiment, the first access information acquired by the call session control function network element may be from the first terminal, or may be from a policy control function network element corresponding to a session of the first terminal, so that it can be ensured that the call session control function network element can flexibly receive the first access information of the first terminal.

In a possible implementation manner, the obtaining, by the network element of a call session control function, the second access information includes:

the call session control function network element obtains the second access information from the second terminal or a policy control function network element corresponding to the session of the second terminal or a call session control function network element corresponding to the second terminal, and the session of the second terminal is used for transmitting the data of the IMS service.

Through the embodiment, the second access information acquired by the call session control function network element may be from the second terminal, or may be from a policy control function network element corresponding to a session of the second terminal, so that it can be ensured that the call session control function network element can flexibly receive the second access information of the second terminal.

In a possible implementation manner, before the determining, by the network element of the call session control function, that direct communication is established between the first terminal and the second terminal according to the first access information and the second access information, the method further includes: the call session control function network element acquires first network direct connection capability information, the first network direct connection capability information indicates that the first network supports the direct communication, and the first terminal and the second terminal are accessed through the first network.

By the embodiment, the call session control function network element determines, according to the first access information and the second access information, that the first network direct connection capability information needs to be received before the first terminal and the second terminal establish direct communication, so that it can be determined that the first network to which the first terminal and the second terminal access supports direct communication.

In a possible implementation manner, before the determining, by the network element of the call session control function, that direct communication is established between the first terminal and the second terminal according to the first access information and the second access information, the method further includes: the call session control function network element receives 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 directly communicate, and the second direct communication subscription information indicates that the second terminal is allowed to directly communicate.

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

By the embodiment, before determining that the first terminal and the second terminal establish the direct communication according to the first access information and the second access information, the network element of the call session control function 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, so as to determine that the first terminal and the second terminal can perform the above-mentioned direct communication.

In a possible implementation manner, before the determining, by the network element of the call session control function, that direct communication is established between the first terminal and the second terminal according to the first access information and the second access information, the method further includes: the call session control function network element obtains first media characteristic support information and second media characteristic support information, wherein 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.

Through the embodiment, before determining that the first terminal and the second terminal establish direct communication according to the first access information and the second access information, the call session control function network element further needs to receive first media characteristic support information of the first terminal and second media characteristic support information of the second terminal, so that it can accurately know that the first terminal and the second terminal support the direct communication of the IMS service.

In one possible embodiment, the first invite request message includes a direct communication request indication message indicating that the first terminal desires the direct communication with the second terminal.

By the embodiment, the first invite request message includes direct communication request indication message, so that the call session control function network element can accurately determine the task requested by the first terminal according to the direct communication request indication message, that is, the first terminal desires to perform the above-mentioned direct communication with the second terminal.

In a possible implementation, the first request information includes identification information of the first terminal and identification information of the second terminal.

Through the implementation manner, 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, so that the first network element can accurately allocate corresponding tunnels to the first terminal and the second terminal according to the identification information of the first terminal and the identification information of the second terminal, and further successfully establish a transmission path between the first terminal and the second terminal, so as to ensure that the direct communication between the first terminal and the second terminal can be performed.

In a possible embodiment, the first request information comprises quality of service, qoS, information for the direct communication.

Through the embodiment, the first request information sent by the call session control function network element to the first network element includes the QoS information for the direct communication, so that the first network element side can further establish a good transmission path for the direct communication between the first terminal and the second terminal according to the QoS information, thereby ensuring the end-to-end QoS and further improving the transmission delay.

In one possible embodiment, the method further comprises: and the call session control function network element sends first invitation response information to the first terminal, wherein the first invitation response information indicates that the first terminal is accepted to perform the direct communication with the second terminal.

Through the embodiment, after determining that the first terminal and the second terminal establish direct communication according to the first access information and the second access information, the network element with the call session control function may further send first invite response information to the first terminal, and notify the first terminal that the above-mentioned direct communication with the second terminal is possible.

In a second aspect, the present application provides a communication apparatus, which is applicable to a call session control function network element and has a function of implementing the first aspect or any one of the possible implementations of the first aspect. The hardware or software includes one or more units corresponding to the above functions. For example, the system comprises a receiving unit, a processing unit and a sending unit.

In a third aspect, the present application further provides a communication apparatus, which is applicable to a call session control function network element and has a function of implementing the first aspect or any one of the possible implementation manners of the first aspect. The apparatus may include: the device comprises a receiving module, a processing module and a sending module.

In a fourth aspect, the present application further provides a communication system, where the system includes a call session control function network element for executing the method provided in the first aspect, and may further include a terminal device on the ground, a policy control function network element, a unified data management network element, and a session management function.

A possible system comprises a user plane function network element and an access network device on a satellite.

It should be understood that the terminal device, the policy control function network element, the unified data management network element, and the session management function on the ground, and the user plane function network element and the access network device on the satellite may be used to perform information interaction with the call session control function network element to assist the call session control function network element in determining that the first terminal and the second terminal establish direct communication.

In a fifth aspect, the present application further provides a computer storage medium, where a software program is stored, and the software program can implement the method provided in the first aspect or any one of the possible implementation manners when being read and executed by one or more processors.

In a sixth aspect, embodiments of the present application further provide a computer program product containing instructions, which when run on a computer, cause the method provided in the first aspect or any one of the possible implementations to be performed.

In a seventh aspect, an embodiment of the present application further provides a chip system, where the chip system includes a processor, configured to support a call session control function network element to implement the functions in the foregoing first aspect.

In one possible design, the system-on-chip further includes a memory for storing necessary program instructions and data for execution by the loading device. The chip system may be constituted by a chip, or may include a chip and other discrete devices.

The technical effects that can be achieved by any one of the possible embodiments of the second aspect or the second aspect can be described with reference to the technical effects that can be achieved by any one of the possible embodiments of the first aspect or the first aspect; and will not be repeated here.

Drawings

Fig. 1 is a schematic view of an application scenario to which a communication method provided in an embodiment of the present application is applied;

fig. 2 is a schematic diagram of a communication system architecture to which a communication method provided in the embodiment of the present application is applied;

fig. 3A is a flowchart illustrating a communication method provided in an embodiment of the present application;

fig. 3B is a simplified flowchart of an example of a communication method provided in an embodiment of the present application;

fig. 4A is a schematic flow chart of a communication example of a multi-IM CN scenario provided in the embodiment of the present application;

fig. 4B is a schematic flow chart of a communication example of a single IM CN scenario provided in the embodiment of the present application;

fig. 5 is a schematic flow chart of an example of another communication method provided in the embodiments of the present application;

fig. 6 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

fig. 7 is a schematic structural diagram of a communication device provided in an embodiment of the present application.

Detailed Description

The embodiments of the present application provide a communication method and apparatus, where the method and apparatus are based on the same or similar technical concepts, and because the principles of solving the problems of the method and apparatus are similar, the apparatus and the method may be mutually referred to, and repeated parts are not described again.

Hereinafter, some terms in the embodiments of the present application will be explained first to facilitate understanding by those skilled in the art.

1) The Call Session Control Function network element related in the embodiment of the present application may be a Call Session Control Function (CSCF) network element in an IMS system architecture, and is responsible for Session Control.

The execution subject in the embodiment of the present application may be a call session control function network element or a chip corresponding to the call session control function network element, and the call session control function network element in the embodiment of the present application may be a physical entity network element or a virtual network element.

2) The Access Network device related in the embodiment of the present application may provide a device for accessing a terminal device, and includes a Radio Access Network (RAN) device and AN device. The RAN device is primarily a 3GPP network wireless network device and the AN may be AN access network device as defined by non-3 GPP. The RAN device is responsible for functions of radio resource management, quality of service (QoS) management, data compression and encryption, etc. on the air interface side. The RAN equipment may include various forms of base stations, such as: macro base stations, micro base stations (also referred to as small stations), relay stations, access points, etc. In systems using different radio access technologies, the names of devices having a base station function may be different, for example, in the fifth generation (5G) system, referred to as RAN or gNB (5G NodeB); in an LTE system, referred to as an evolved node B (eNB or eNodeB); in third generation (3 rd generation, 3G) systems, they are referred to as Node Bs, etc. The present application does not limit the specific form of the access network device.

3) The policy control function network element related in the embodiment of the present application may be a PCF network element in a communication system architecture, and is configured to provide policy rules for a network entity to implement, and may support a unified policy framework to manage network behaviors and access subscription information stored in unified data. For example, the policy control network element in the embodiment of the present application is configured to issue a rule to the session management network element, and is further configured to manage a traffic flow, that is, modify or delete a quality of service parameter of the traffic flow.

The execution main body in the embodiment of the present application may be a policy control function network element or a chip corresponding to the policy control function network element, and the policy control function network element in the present application may be a physical entity network element or a virtual network element, and the present application does not limit the specific form of the policy control function network element.

4) The internet protocol multimedia subsystem IMS, i.e. the IP-based multimedia system, referred to in the embodiments of the present application may also be referred to as an IP multimedia subsystem. The IMS system provides packet data packet-switched oriented multimedia services and platforms for next generation IP-based mobile networks. The method can meet the requirements of the current terminal client on more novelty and diversification of multimedia services. At present, IMS is considered as a core technology of a next-generation network, and is also an important way to solve the problem of convergence between mobile and fixed networks and to introduce triple-convergence of voice, data, and video, and other differentiated services.

It should be noted that, the IMS system mentioned in this application refers to all or part of network elements in the IMS system, for example, network elements related to a call session control function for processing session control, network elements related to processing media data, and the like, and may correspond to different network elements in different contexts, which is not limited in this application.

5) The access information related in the embodiment of the present application may be access type indication information of the terminal, where the access type indication information may indicate that the terminal accesses the network through a satellite or indicate that the terminal accesses the network through another method, and the access type indication information may also be access type information or access technology type information, which is not specifically limited in this application.

6) The Quality of Service (QoS) referred to in the embodiments of the present application may generally represent the sum of features and characteristics of a Service that can satisfy a specification and a potential requirement, that is, the degree to which a Service job can satisfy the requirement of a served person.

In the solution of the present application, the qos can be expressed as a technology for effectively managing network resources, and for different requirements of various services, end-to-end qos assurance can be provided. Specifically, a network may utilize various basic technologies to provide better service capability for a specific network communication, so as to avoid problems such as network delay and congestion, and for a network with limited capacity, especially for streaming multimedia applications such as Voice over Internet Protocol (VoIP) and Interactive television over Internet Protocol (IPTV), since such media applications need a fixed transmission rate and are sensitive to delay, it is very important to ensure service quality.

In summary, qoS may refer to an overall performance measure of a service experienced by a network user, for example, qoS may be measured by measuring QoS packet loss rate, bit rate, throughput, transmission delay, availability, jitter, and other relevant aspects of the service.

7) The media characteristics related in the embodiment of the present application may be expressed as a usage function that can be supported by the terminal, for example, the terminal device may be used for media features such as voice communication, video communication, or photographing, and in addition, the media characteristics may also be attributes of the terminal, and the present application does not specifically limit the specific attributes. The media characteristics referred to in the embodiments of the present application are media characteristics of voice communication of the terminal device.

8) The direct communication subscription information related in the embodiment of the present application may indicate that the terminal subscribes to a preset function, and may perform direct communication through a satellite to implement the preset function. The content of the specific subscription is not specifically limited in the present application.

9) The plurality referred to in the embodiments of the present application means two or more.

In addition, it is to be understood that the terms first, second, etc. in the description of the present application are used for distinguishing between the descriptions and not necessarily for describing a sequential or chronological order.

Please refer to fig. 1, which is a schematic diagram of a satellite mobile communication scenario applicable to the embodiment of the present application. As shown in fig. 1, in the satellite mobile communication system, a satellite 1 is loaded with a base station 1 and a user plane function network element 1, and a satellite 2 is loaded with a base station 2 and a user function network element 2. The terminal device 1 can access the base station 1 on the satellite 1 through a wireless communication mode to realize communication with the satellite 1, the base station 1 on the satellite 1 can establish communication connection with the base station 2 on the satellite 2, and the terminal device 2 can also access the base station 2 on the satellite 2 through a wireless communication mode to realize communication with the satellite 2. When the terminal device 1 transmits voice data to the terminal device 2, the voice data is transmitted according to the path of the line 1, that is, the voice data of the terminal device 1 is transmitted to the satellite 1, then the satellite 1 transmits the voice data to a terrestrial IP Multimedia Subsystem (IMS) system, and further the voice data is transmitted from the IMS system to the satellite 2, and finally the satellite 2 transmits the voice data to the terminal device 2. However, when transmitting through this path, the distance between the ground and the satellite is long, which results in a long time delay for voice communication between the terminal device 1 and the terminal device 2, and thus the user experience is poor. It should be noted that, in this scenario, the ground may also deploy the UPF, and at this time, the media data may first pass through the UPF deployed on the ground after reaching the ground through the user plane network element on the satellite, and then pass through the IMS system, or may directly reach the IMS system after reaching the ground through the user plane network element on the satellite, which is not limited in this application.

Therefore, the present application provides a communication method, which can support the terminal device 1 and the terminal device 2 to perform direct communication through a satellite, thereby reducing the time delay generated when the terminal device 1 and the terminal device 2 perform the IMS service, and greatly improving the user experience. It should be noted that, when IMS services are mentioned in the present application, voice communication is often taken as an example.

It should be noted that the communication method provided in the embodiment of the present application may be applied not only to the above-mentioned 5G system architecture, but also to, but not limited to, a Long Term Evolution (LTE) communication system and various wireless communication systems that evolve in the future.

The following describes specific network elements/modules in the 5G system architecture in detail.

Referring to fig. 2, the 5G system mainly includes: network Slice Selection Function (NSSF) Network elements, network open Function (NEF) Network elements, network storage Function (NF) Network elements, policy Control Function (PCF) Network elements, unified Data Management (UDM) Network elements, application Function (AF) Network elements, authentication service Function (AUSF) Network elements, access and Mobility Management Function (AMF) Network elements, session Management Function (Session Management Function, SMF) Network elements, terminal (User Equipment, UE), access Network ((Radio) Network, (R) AN) device, user plane Function (User Function, network Function (SMF) Network elements, network Data (upnp) Network elements, network distribution Network (NEF) Data. For convenience of description, taking the policy control function as an example, the policy control function network element may be referred to as a PCF network element for short, and other network elements are the same and will not be described again.

Referring to fig. 2, nnnsf, nnef, nausf, nrrf, namf, npcf, nsmf, numm, naf are service-based interfaces exposed by NSSF, NEF, AUSF, NRF, SMF, PCF, SMF, UDM, AF, respectively; referring to fig. 2, N1 is a reference point between the UE and the AMF, N2 is a reference point between the (R) AN and the AMF, N3 is a reference point between the (R) AN and the UPF, N4 is a reference point between the SMF and the UPF, and N6 is a reference point between the UPF and the DN.

PCF network element: the method is used for providing policy rules for network entity enforcement, and can support a unified policy framework to manage network behaviors and access subscription information of a unified data storage (UDR).

UDM network element: for uniformly managing user data, storing authentication certificates/parameters, and storing and managing a Permanent user ID (or a Permanent Identifier (SUPI) of the UE) of the 5G system, and a service network element registration management (such as an AMF, an SMF, etc. currently providing services for the terminal) of the user.

The SMF network element: the method is used for tunnel maintenance, IP address allocation and management, UP function selection, policy implementation, control in QoS, charging data acquisition, roaming and the like.

UE: a handheld terminal, a notebook computer, a subscriber unit (subscriber unit), a cellular phone (cellular phone), a smart phone (smart phone), a wireless data card, a Personal Digital Assistant (PDA) computer, a tablet computer, a wireless modem (modem), a handheld device (hand held), a laptop computer (laptop computer), a cordless phone (cordless phone) or a Wireless Local Loop (WLL) station, a Machine Type Communication (MTC) terminal or other network accessible devices. The terminal equipment and the access network equipment adopt a certain air interface technology to communicate with each other.

(R) AN device: the equipment for providing access for the terminal equipment comprises RAN equipment and AN equipment. The RAN device is primarily a 3GPP network wireless network device and the AN may be AN access network device as defined by non-3 GPP. A Radio Access Network (RAN) device: the wireless network controller is mainly responsible for functions of wireless resource management, quality of service (QoS) management, data compression, encryption and the like on the air interface side. The RAN equipment may include various forms of base stations, such as: macro base stations, micro base stations (also referred to as small stations), relay stations, access points, etc. In systems using different radio access technologies, the names of devices having a base station function may be different, for example, in the fifth generation (5G) system, referred to as RAN or gNB (5G NodeB); in an LTE system, referred to as an evolved node B (eNB or eNodeB); in third generation (3 rd generation, 3G) systems, they are referred to as Node Bs, etc.

UPF network element: for routing and forwarding of user data packets, data interaction with an external data network DN, qoS processing of the user plane, flow control rule enforcement (e.g., gating, redirection, traffic steering), etc.; data network DN: refers to a Service network providing data transmission Service for users, such as IMS (IP multimedia Service), internet, etc. Such as operator services, internet or third party services, etc.; the UE accesses a Data Network (DN) through a PDU (Packet Data Unit) session established between the UE and the DN.

Each network element in the core network may also be referred to as a functional entity or a device, and may be a network element implemented on dedicated hardware, a software instance running on dedicated hardware, or an instance of a virtualized function on an appropriate platform, for example, the virtualized platform may be a cloud platform.

It should be noted that the architecture of the communication system shown in fig. 2 is not limited to include only the network elements shown in the figure, and may also include other devices not shown in the figure, which are not specifically listed here.

It should be noted that the embodiment of the present application does not limit the distribution form of each network element, and the distribution form shown in fig. 2 is only an example, and the present application is not limited.

For convenience of description, in the following description, the network element shown in fig. 2 is taken as an example, and the XX network element is directly abbreviated as XX, for example, an SMF network element is abbreviated as SMF. It should be understood that the names of all network elements in the present application are only used as examples, and may also be referred to as other names in future communications, or network elements referred to in the present application may also be replaced by other entities or devices with the same functions in future communications, and the present application does not limit the present application. The unified description is made here, and the description is not repeated.

It should be noted that the names of all messages and information in this application are only examples, and may be other names, which are not limited in this application. It should be understood that the messages or information from the network element 1 to the network element 2 may be messages sent directly from the network element 1 to the network element 2, or may be sent indirectly, for example, the network element 1 sends a message to the network element 3 first, the network element 3 then sends a message to the network element 2, and finally the messages or information are sent to the network element 2 through one or more network elements.

The IMS system architecture in the embodiment of the present application is described in detail below.

An IMS system includes one or more Call Session Control Function (CSCF), media Gateway Control Function (MGCF) network elements, an IMS Media Gateway, a multimedia resource Function processor, a Subscription Location Function (SLF), an interrupt Gateway Control Function, and an application server.

Components that are mainly used in IMS systems in general include: home subscriber service, call Session Control Function (CSCF) network elements, a security gateway, an IP media server and an application server.

The home subscriber service mainly stores subscriber and service related data such as subscriber identity, registration information, access parameters, service trigger information, etc. The HSS also has a user positioning function and an identity authentication function.

The call session control function network element is composed of a plurality of subcomponents, specifically, the subcomponents include: a Proxy-Call Session Control Function (P-CSCF) network element, an interrogating-Call Session Control Function (I-CSCF) network element, and a Serving-Call Session Control Function (S-CSCF) network element.

P-CSCF network element: the user accesses the first contact point of the IMS network during the service application process. It is responsible for acting on all SIP signaling and completing the route control of the call; providing QoS resource reservation; supporting SIP signaling compression to improve the bandwidth utilization efficiency of an air interface; providing NAT control to support NAT traversal of an enterprise network; meanwhile, a security association with the UE can be maintained to protect the privacy and integrity of signaling with the UE. Possibly represented as AF, interacting with network elements such as PCF.

I-CSCF network element: the unified entry point of the user home network is responsible for the allocation of the S-CSCF and the query of the S-CSCF where the called party is located. And simultaneously, the function of topology hiding between IMS domains is also completed.

S-CSCF network element: the service switching center of the IMS network is mainly responsible for receiving and processing registration requests of UE, user management, session control, service switching, service control, SIP information processing, charging and the like, and can trigger SIP requests to corresponding AS according to an application triggering principle. May interact with UDM network elements.

It should be noted that the CSCF network elements corresponding to the terminal device 1 and the terminal device 2 may be the same or different, and this is not limited in this application. The multi-IM CN (IP multi-media Core Network, internet protocol multimedia Core Network) mentioned in the description means that CSCF Network elements corresponding to the terminal device 1 and the terminal device 2 are different, and the single IM CN means that the CSCF Network elements corresponding to the terminal device 1 and the terminal device 2 are the same.

The gateways are communication channels between telecommunication networks and between enterprises and telecommunication networks. It mainly controls the access of messages to and from NAT (network address translation) servers and firewalls, and may also assume some other security functions, such as packet filtering, etc. In addition, the security gateway also has the functions of enforcing security policies between IMS domains, securing control plane messages to and from IMS domains, and setting and maintaining IPsec Security Associations (SAs).

The IP media server has all the streaming media functions and can provide rich multimedia messages, such as texts. It is responsible for managing the associated transcoding tasks of the encoder (encoding/decoding) and streaming media, as well as echo cancellation, voice detection, and voice generation. The IP media server can also provide stream multiplication and stream broadcasting to meet the needs of the conferencing application, and can also be connected to a circuit switched network.

The application server provides multimedia services for the IMS network, and it has to provide access rights for all other IMS components, such as SIP servlets. The application server can also be used for deploying new services, and the IMS adopts a modular architecture, so that new service deployment can be completed only by replacing or upgrading the application server. Such a strategy is completely different from the previous vertical model, where services are always deployed as a single point solution, each using its own set of proprietary devices. The application servers may be located in the home network or in a third party network, and if located in the third party network, they cannot interface with the HSS. Since the application servers belong to OSA (open service architecture) application servers, they can securely access the IMS from the external network and connect to GSM CAMEL (customized applications for mobile enhanced logic) servers.

The embodiment of the present application provides a communication method, which is applicable to the scenario of satellite communication in fig. 1, and is applicable to, but not limited to, a 5G system architecture shown in fig. 2, and the method may be executed by a network element related to the present application, or executed by a chip corresponding to the related network element, where the network element in the present application may be a physical entity network element or a virtual network element, and the form of the related network element is not specifically limited in the present application.

Referring to fig. 3A, a specific flowchart of a communication method provided in the embodiment of the present application is shown, where the method may specifically include the following steps:

S301A: and the call session control function network element receives the first invitation request information of the first terminal.

This step S301A may refer to S301B in the example simplified flow as shown in fig. 3B, i.e. the CSCF network element receives the first invite request information from the UE 1.

In one embodiment, the receiving, by a call session control function network element, first invite request information of a first terminal includes: the first invite request information includes direct communication request indication information indicating that the first terminal desires to perform direct communication with the second terminal.

It should be understood that the first invite request message is for initiating a session request to an invitee, for example, the first terminal is an inviter, the second terminal is an invitee, the first terminal invites the second terminal to join a session, and when the first terminal needs to request a session for voice communication with the second terminal, the first invite request message sent by the first terminal is used for requesting direct communication with the second terminal.

In addition, direct communication as referred to in this application refers to data of an internet protocol multimedia subsystem, IMS, service between a first terminal and a second terminal being transmitted directly between a first satellite of the first terminal access network and a second satellite of the second terminal access network.

Optionally, the first invitation request information may further include identity information of the first terminal and identity information of the second terminal.

It should be noted that the first invite request message may further include access type indication information of the first terminal and/or media characteristic support information of the first terminal. The access type indication information of the first terminal indicates that the first terminal accesses the network through the satellite; the media characteristic support information of the first terminal may be used to indicate that the first terminal supports media characteristics of an IMS service for direct voice communication.

The media characteristics supported by the UE1 may include a voice data coding and decoding manner supported by the first terminal and used for the direct voice communication, which is not specifically limited in this application.

In one embodiment, the first invite request message includes Access Network information (P-Access-Network-Info, PANI). If the PANI includes the access type information, the access type indication information is the access type information, and the access type information indicates satellite access, such as low-orbit satellite access, medium-orbit satellite access, and high-orbit satellite access. If the PANI includes the access technology type information, the access type indication information is the access technology type information, and the access technology type information indicates a satellite access technology, such as a low-orbit satellite access technology, a medium-orbit satellite access technology, and a high-orbit satellite access technology.

S302A: and the call session control function network element acquires the first access information and the second access information.

In one embodiment, the obtaining, by a call session control function network element, first access information and second access information includes: the call session control function network element may obtain a first access information received by the policy control function network element corresponding to a session from the first terminal or the first terminal, where the session of the first terminal is used to transmit data of the IMS service; and the call session control function network element acquires the second access information from the second terminal or a policy control function network element corresponding to the 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 for transmitting the data of the IMS service. The first access information indicates that the first terminal accesses the network through the satellite, and the second access information indicates that the second terminal accesses the network through the satellite.

It should be noted that the first access information and the second access information may also be used as access type indication information to indicate that the first terminal and the second terminal access through a satellite, which may be specifically referred to in step S301 above, and details are not described here again.

S303A: and the call session control function network element determines to establish direct communication for the first terminal and the second terminal according to the first access information and the second access information.

In one embodiment, before the determining, by the network element of the call session control function, that the first terminal and the second terminal establish the direct communication according to the first access information and the second access information, the method further includes: the call session control function network element obtains first network direct connection capability information, the first network direct connection capability information indicates that a first network supports the direct communication, and the first terminal and the second terminal are accessed through the first network.

Specifically, the call session control function network element may obtain the first network direct connection capability information from the policy control function network element. The first network straight-through capability information may also be received from other network elements, which is not specifically limited in this application.

When the call session control function network element acquires the first network direct connection capability information from the policy control function network element, the method may specifically include: the call session control function network element sends authentication authorization request information to the policy control function network element, optionally, the authentication authorization request information includes network direct communication capability request information, the network direct communication capability request information requests to obtain information on whether the network supports direct communication, further, the call session control function network element receives authentication authorization response information from the policy control function network element, and the authentication authorization response information may carry the first network direct communication capability information.

In one embodiment, before the determining, by the network element of the call session control function, that direct communication is established between the first terminal and the second terminal according to the first access information and the second access information, the method further includes: and the call session control function network element receives first direct communication signature information and second direct communication subscription information, wherein the first direct communication signature information indicates that the first terminal is allowed to directly communicate, and the second direct communication subscription information indicates that the second terminal is allowed to directly communicate.

Specifically, the call session control function network element may obtain the first direct communication subscription information and the second direct communication subscription information from the unified data management network element. Before receiving the first direct communication subscription information and the second direct communication subscription information from the unified data management network element, the call session control function network element needs to send subscription data request information of the first terminal to the unified data management network element, where the subscription data request information is used to request subscription data of the first terminal. The subscription data request information may include subscription data type information, and the subscription data type information may also indicate that the type of the subscription data is satellite communication subscription data or direct communication subscription data.

It should be understood that the above-mentioned first direct communication subscription information and second direct communication subscription information may indicate that direct communication between the first terminal and the second terminal is allowed, or may indicate that direct communication between the first terminal and the second terminal is not allowed, which may be indicated according to actual situations.

In one embodiment, before the determining, by the network element of the call session control function, that the direct communication is established between the first terminal and the second terminal according to the first access information and the second access information, the method further includes: a call session control function network element acquires first media characteristic support information of a first terminal and second media characteristic support information of a second terminal; the first media characteristic support information indicates a media characteristic used by the first terminal for the IMS service, and the second media characteristic support information indicates a media characteristic used by the second terminal for the IMS service.

Specifically, the network element with a call session control function may obtain first media characteristic support information of the first terminal from the first terminal, and obtain second media characteristic support information of the second terminal from the second terminal. The media characteristic support information may be used to indicate a media characteristic that the terminal supports direct voice communication, and may also be used to indicate a media characteristic that the terminal does not support direct voice communication, which is not specifically limited in this application. The media characteristics supported by the terminal may include a voice data encoding and decoding manner supported by the first terminal and used for the direct voice communication, which is not specifically limited in this application.

In one embodiment, the first media characteristics support information and the second media characteristics support information of the second terminal need to be matched, i.e. all or part of the media support information of the first terminal and all or part of the second media characteristics support information have to be identical.

It should be noted that, in the case that the network element of the call session control function determines that the information obtained in the foregoing embodiment both indicates that the first terminal and the second terminal and the network support direct communication, it may be determined that the first terminal and the second terminal establish direct communication. And if any one of the first terminal and the second terminal does not support the direct communication, determining that the first terminal and the second terminal cannot establish the direct communication.

For example, the step S302A-S303A, where the call session control function network element determines the information interacted before the first terminal and the second terminal establish the direct communication, may refer to S302B shown in fig. 3B, that is, the CSCF interacts with the PCF/UDM for the satellite access type, the direct communication capability information, and the direct communication support information.

The step S302A-S303A in which the call session control function network element determines that the first terminal and the second terminal establish the direct communication may refer to S305B in the example simplified flow shown in fig. 3B, that is, the CSCF determines to accept the direct voice communication. In addition, the determining, by the network element of the call session control function, before the first terminal and the second terminal establish the direct communication, further includes sending second invitation request information to the second terminal, and receiving second invitation response information from the second terminal, so as to ensure that the second terminal agrees to accept establishment of the direct communication with the first terminal, which may refer to S303B-S304B in the example simplified flow shown in fig. 3B.

S304A: and the call session control function network element sends first request information to a first network element, wherein the first request information indicates that the first terminal and the second terminal are in direct communication.

For example, the step S304A of sending the first request message to the first network element by the call session control function network element may refer to S306B in the example simplified flow shown in fig. 3B, that is, establishing the direct communication message.

Further, the step S307B may refer to S307B-S309B in the example simplified flow shown in fig. 3B, and how to establish the communication tunnel (transmission path) is not specifically limited in this application.

Optionally, the first request message includes address information of the first terminal and address information of the second terminal, or includes other identification information of the first terminal and the second terminal. And the first request information may further include quality of service QoS information for direct communication between the first terminal and the second terminal.

In one embodiment, after determining that the direct communication between the first terminal and the second terminal is established, the call session control function network element may further send, to the first terminal, first invite response information indicating that the direct communication between the first terminal and the second terminal is accepted. This step may be referred to as S310B in the example simplified flow shown in fig. 3B.

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 sends the first invite response message to the first terminal, where the first invite response message may be used to indicate that the first terminal is rejected from performing direct communication with the second terminal. In addition, the first network element in this application may include a policy control function network element and a unified data management network element, and may also include other network elements, which is not specifically limited in this application.

It should be noted that, in the communication method provided in the present application, the first terminal and the second terminal may execute the above steps through the same call session control function network element, that is, a single IM CN scenario; the first terminal and the second terminal can also execute the steps through different call session control function network elements, namely, the scene of the multi-IM CN is obtained.

To sum up, in the communication method provided by the present application shown in fig. 3A, in the method, a network element with a call session control function receives first invite request information of a first terminal, and then obtains first access information of the first terminal and second access information of a second terminal, where the first access information indicates that the first terminal accesses through a satellite, and the second access information indicates that the second terminal accesses through the satellite; and finally, the call session control function network element sends first request information to the first network element to indicate direct communication between the first terminal and the second terminal. The method can ensure that the IMS service data transmitted by the first terminal and the second terminal do not pass through the ground, thereby reducing the time length of IMS service between the first terminal and the second terminal and greatly improving the user experience.

Based on the communication method provided by the above embodiment, the method of the present application will be described in detail below with reference to a specific embodiment. The embodiment mainly realizes the direct voice communication of the terminal through the satellite in a multi-IM CN scene. In this embodiment, the UE1 and the UE2 may respectively access the network through a corresponding satellite, that is, the UE1 may access the network through the first satellite, the UE2 may access the network through the second satellite, each satellite includes an access device (e.g., a base station gNB1, a gNB 2) and a UPF network element, and the UE1 and the UE2 are respectively served by a corresponding CSCF network element, that is, one call session control function corresponding to the UE1 may be represented by a CSCF #1 network element, and one call session control function corresponding to the UE2 may be represented by a CSCF #2 network element, where the call session control function CSCF #1 network element includes one or more of a P-CSCF #1 network element, an I-CSCF #1 network element, and an S-CSCF #1 network element, and the call control function CSCF #2 network element includes one or more of a P-CSCF #2 network element, an I-CSCF #2 network element, and an S-CSCF #2 network element.

Referring to fig. 4A, an execution object of the network side involved in this embodiment is a network element, a CSCF network element in this embodiment is a call session control function network element in fig. 3A, a UDM network element in this embodiment is unified data management in fig. 3A, a PCF network element in this embodiment is a policy control function network element in fig. 3A, a UPM network element in this embodiment is a user plane function network element in fig. 3A, and a specific implementation flow of this embodiment is as follows:

s401: the terminal UE1 sends first invite request information to the P-CSCF #1 network element, the first invite request information requesting communication with the second terminal UE2.

Correspondingly, the P-CSCF #1 network element receives the first invitation request information,

Alternatively, the first INVITE request message may be an INVITE request message.

Specifically, the first invite request message includes identity information of UE1 and identity information of UE2. Such as identification information of UE1 and identification information of UE2.

Optionally, the first invite request message includes first access type indication information, where the first access type indication information indicates that the UE1 accesses the network through the satellite. It is to be noted that the first access type indication information may also indicate other access types. Without being particularly illustrated, the first access type indication information indicates that the UE1 accesses the network through a satellite.

In a first implementation manner, the first invite request information includes Access Network information (P-Access-Network-Info, PANI), where the PANI includes first Access Type (Access Type) information, that is, the first Access Type indication information is Access Type information, and the first Access Type information indicates that the UE1 accesses the Network through a satellite. The first access type information is not limited to how to indicate the UE1 to access the network through the satellite, for example, the UE1 accesses the network through the low-orbit satellite, the UE1 accesses the network through the medium-orbit satellite, and the UE1 accesses the network through the high-orbit satellite.

In a second implementation manner, the first invite request information includes PANI (P-Access-Network-Info, access Network information), and when the PANI includes first Access technology Type (RAT Type) information, the first Access technology Type indication information is first Access technology Type information, and the first Access technology Type information indicates a satellite Access technology Type.

Optionally, the first invite request information may further include first direct communication request indication information and first media characteristic support information; wherein the first direct voice communication request indication information indicates that the UE1 requests direct voice communication with another terminal UE2 through a satellite, and the first direct voice communication indicates that data of the voice communication between the UE1 and the UE2 only passes through the UE1, the satellite and the UE2. The first media characteristic support information indicates that the UE1 supports the media characteristic for the direct voice communication. It should be noted that the first media characteristic support information may also indicate that the UE1 does not support the media characteristic for direct voice communication, and in a case that no special description is made, the first media characteristic support information indicates that the UE1 supports the media characteristic for direct voice communication, and the media characteristic supported by the UE1 may include a voice data codec mode supported by the UE1 for the direct voice communication. It should be understood that direct voice communication is direct communication as described above.

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

Correspondingly, the PCF network element receives the first authentication authorization request message.

Optionally, the first Authentication Authorization Request Message may be an Authentication Authorization Request Message, which is abbreviated as AA-Request Message or AAR Message.

The first authentication and authorization request message requests whether the voice communication of the UE1 conforms to Policy and Charging Control supervision permission for authentication and authorization.

In an implementation manner, if the first invite request message received by the P-CSCF #1 network element includes one or more of the first access type indication message and the first direct communication request indication message in S401, the first authentication authorization request message sent by the P-CSCF #1 network element to the PCF network element includes a first network direct communication capability request message, and the first network direct communication capability request message requests to obtain information whether the network supports direct communication between satellites.

It should be appreciated that the direct communication between the satellites may establish a link between the satellites to transmit voice data. And the network is formed by satellite and network elements on the ground.

In a second implementation manner, if the first invite request message received by the P-CSCF #1 network element includes one or more of the first access type indication message and the first direct communication request indication message in S401, the first authentication authorization request message sent by the P-CSCF #1 network element to the PCF network element includes the first direct communication indication message, and the first direct communication indication message indicates that the UE1 needs to directly communicate. If the first authorization request information contains the first direct communication indication information, the first authentication authorization request information requests to authenticate and authorize whether the direct voice communication of the UE1 accords with the policy and the charging control supervision.

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

Correspondingly, the P-CSCF #1 network element receives the first authentication authorization response message.

Optionally, the first Authentication Authorization response Message may be an Authentication Authorization Answer Message, which is AA-Answer information or AAA information for short.

Optionally, the first authentication authorization response message includes access type indication information, where the access type indication information indicates that the first terminal accesses the network through the satellite.

In a first implementation manner, the first invite request message in step S401 does not include the access type indication message, and the first authentication authorization response message in step S403 includes the first access type indication message. The first access type indication information is the same as the first access type indication in step S401, and is not described herein again.

In a second implementation manner, the first invite request message in step S401 includes first access type indication information, the first access type indication information in step S401 is first access type information, and the first authentication and authorization response message in step S403 includes first access type indication information which is the first access technology type information in step S401. The first access technology type information is synchronized with the first access technology type information in step S401, which is not described herein again.

In a third implementation manner, 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, the first authentication and authorization response information includes the first network direct communication capability information and the first direct communication authorization result information.

It should be understood that the first direct communication authorization result information indicates that the UE1 is allowed or not allowed to perform the above direct voice communication. The first network direct communication capability information indicates that the network to which the UE1 is connected supports or does not support direct communication between satellites, and the direct communication between satellites is as described in step 2.

In a fourth implementation manner, if the first authentication and authorization request information includes the first direct communication indication information, the first authentication and authorization response information includes the first direct communication authorization result information.

It should be noted that the above steps S402 and S403 are optional steps.

S404: and the P-CSCF #1 network element sends second invitation request information to the S-CSCF #1 network element.

Accordingly, the S-CSCF #1 network element receives the second invite request information.

It should be understood that the P-CSCF #1 Network element and the S-CSCF #1 Network element, I-CSCF #1 Network element are all Network elements serving UE1, i.e. belonging to the Originating Network (Originating Network).

In one implementation, the second invite request information includes one or more of first access type indication information and first network direct communication capability information. The first access type indication information and the first network direct communication capability information are the same as the first access type indication information and the first network direct communication capability information in the above step S403.

In a second implementation manner, the second invitation request message includes first direct communication indication message, which is the same as the first direct communication indication message in the first authentication and authorization request message in step S402.

In a second implementation manner, the following situations may be specifically included:

in a first case, if at least one of the first invitation request message in step S401 and the first authentication authorization response message in step S403 includes the first access type indication message, the second invitation request message includes the first direct communication indication message.

In a second case, if at least one of the first invite request message in the step S401 and the first authentication authorization response message in the step S403 includes the first access type indication message, and the first network direct communication capability information indicates that the network supports direct inter-satellite communication, the second invite request message includes the first direct communication indication message.

In a third case, if at least one of the first invite request message in step S401 and the first authentication and authorization response message in step S403 includes the access type indication message, and the first direct communication authorization result message included in the first authentication and authorization response message indicates that the UE1 is allowed to perform direct voice communication, the second invite request message includes the first direct communication indication message.

It should be noted that, if at least one of the first invite request message in the step S401 and the first authentication authorization response message in the step S403 includes the first access type indication message, and the first network direct communication capability information in the first authentication authorization response message indicates that the network to which the UE1 is accessed does not support direct satellite communication, or the first direct communication authorization result message indicates that the UE1 is not allowed to perform direct voice communication, the second invite request message does not include the first direct communication indication message.

In addition, if at least one of the first invite request message in step S401 and the first authentication authorization response message in step S403 includes the first access type indication message, and the first network direct communication capability information in the first authentication authorization response message 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 direct voice communication, step S430 is performed directly, that is, the P-CSCF #1 network element sends the first invite response message to UE1, and the first invite response message indicates that direct voice communication is rejected. In this case, the first invite response message includes first direct communication result indication information indicating that direct voice communication is to be rejected or information itself indicating that direct voice communication is to be rejected.

It should be noted that the preferred scheme in this embodiment is: the second invite request message includes one or more of the first access type indication message and the first network direct communication capability message, but does not include the first direct communication indication message.

The 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.

In addition, if the first invite request information in step S401 includes the first media characteristic support information, the second invite request information may also include the first media characteristic support information, and the first media characteristic support information is the same as the first media characteristic support information in step S401, and is not described herein again in detail.

S405: and the S-CSCF #1 network element sends first subscription data request information to the UDM network element.

Correspondingly, the UDM network element receives the first subscription data request message. The first subscription data request message requests subscription data of the UE 1.

In a first implementation manner, the first subscription data request information includes first subscription data type information, where the first subscription data type information indicates that the type of the UE1 subscription data is satellite communication subscription data.

Accordingly, the first subscription data type information may indicate that the type of the subscription data is the direct communication subscription data. Or if the second invite request message includes one or more of first access type indication message, first network direct communication capability message, and first direct communication indication message, the first subscription data request message includes the first subscription data type message.

It should be noted that, when the S-CSCF #1 network element requests the UDM network element for the subscription data of UE1, the S-CSCF #1 network element may also request the subscription data of UE2, and therefore, the first subscription data request information may include subscription data type information of UE1 and subscription data type information of UE2, which is the same as the above. In this case, the following steps S409 and S410 are not performed.

S406: and the UDM network element sends the first subscription data response information to the S-CSCF #1 network element.

Correspondingly, the S-CSCF #1 network element receives the first subscription data response message.

In an implementation manner, the first subscription data request message in step S405 includes first data type information, and the first data type information indicates that the type of the subscription data of the UE1 is satellite communication subscription data, and then the first subscription data response message includes first direct communication support information. The first direct communication support information indicates that the UE1 supports or does not support direct voice communication, i.e., allows the first terminal to directly communicate.

In another implementation manner, in step S405, the S-CSCF #1 may further request subscription data of the UE2, and the first direct communication support information indicates that the first terminal is allowed to directly communicate and the second terminal is allowed to directly communicate, that is, the UE1 and the UE2 support direct communication.

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

S407: and the S-CSCF #1 network element sends third invitation request information to the I-CSCF #2 network element.

Accordingly, the I-CSCF #2 network element receives the third invite request information.

It should be understood that the P-CSCF #2 Network element, the S-CSCF #2 Network element, and the I-CSCF #2 Network element are Network elements serving the UE2, i.e. belonging to a called party Network (Terminating Network).

In an implementation manner, if the second invite request information received by the S-CSCF #1 in the step S404 includes one or more of first access type indication information, first network direct communication capability information, first media characteristic support information, and first direct communication indication information, the third invite request information sent by the S-CSCF #1 network element to the I-CSCF #2 network element in the step S407 includes the first direct communication indication information.

In a second implementation manner, in the step S406, if the first direct communication support information in the first subscription data response information indicates that the UE1 supports direct voice communication, the third invitation request information includes the first direct communication indication information.

In a third implementation manner, in the step S406, if the first direct communication support information in the first subscription data response information indicates that the UE1 does not support direct voice communication, the third invite request information does not include the first direct communication indication information.

It should be noted that, in the step S406, if the first direct communication support information in the first subscription data response information indicates that the UE1 does not support direct voice communication, the step S407 may not be executed, and the S-CSCF #1 network element sends the third invite response information to the P-CSCF #1 network element, where the third invite response information indicates that the direct voice communication is rejected. Then, the following step S429 is directly performed, which is the same as the step S404 and is not described in detail here.

S408: and the network element of the I-CSCF #2 sends the fourth invitation request information to the network element of the S-CSCF # 2.

Accordingly, the S-CSCF #2 network element receives the fourth invite request information.

Specifically, the fourth invite request message includes one or more of first direct communication indication message, first access type indication message, first direct communication support message, first network direct communication capability message, and first media characteristic support message.

It should be noted that in a preferred embodiment of the present invention, only the first direct communication indication information may be included in the third invitation request information of step S407 and the fourth invitation request information of step S408. In this embodiment, the invitation request information in step S407 and step S408 does not include the first direct communication indication information, but includes one or more of the first access type indication information, the first direct communication support information, the first network direct communication capability information, and the first media characteristic support information.

In this embodiment alternative, the first access type indication information must be included in the third invitation request information of step S407 and the fourth invitation request information of step S408.

S409: and the S-CSCF #2 network element sends second subscription data request information to the UDM network element.

Correspondingly, the UDM network element receives the second subscription data request message, which requests the subscription data of the UE2.

Optionally, the second subscription data request information includes second subscription data type information, where the second subscription data type information indicates that the type of the UE2 subscription data is satellite communication subscription data.

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

In a second implementation manner, if the 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, the second subscription data request information includes the second subscription data type information.

If the subscription data of UE2 is queried in step S405, step S409 and step S410 are not executed.

S410: and the UDM network element sends second subscription data response information to the S-CSCF #1 network element.

Correspondingly, the S-CSCF #1 network element receives the second subscription data response message.

Optionally, the second subscription data response message includes second direct communication support information, where the second direct communication support information indicates that the UE2 supports or does not support direct voice communication, that is, the UE2 supports or does not support direct voice communication with another terminal through a satellite, that is, the UE2 is allowed to directly communicate.

In a first implementation manner, if the second subscription data request information includes second subscription data type information, and the second subscription data type information indicates that the type of the UE2 subscription data is satellite communication subscription data, the second subscription data response information includes second direct communication support information.

It should be noted that the steps S409 to S410 are optional steps.

S411: and the S-CSCF #2 network element sends the fifth invitation request information to the P-CSCF #2 network element.

Accordingly, the P-CSCF #2 network element receives the fifth invite request information.

Optionally, the fifth invite request message includes second direct communication indication message, and the second direct communication indication message synchronizes the first direct communication indication message in step S402.

In one implementation, if the fourth invite 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, the fifth invite request information includes the second direct communication indication information.

In a second implementation manner, if the second subscription direct communication support information in step S410 indicates that the UE2 supports direct voice communication, the fifth invite request information includes the second direct communication indication information.

It should be noted that, in the second implementation manner, if the second subscription direct communication support information in step S410 indicates that the UE2 does not support direct voice communication, the fifth invite request information does not include the second direct communication indication information. Or else, without executing step S411, the S-CSCF #2 network element sends fourth invite response information to the I-CSCF #2 network element, the fifth invite response information indicating that the direct voice communication is rejected, the I-CSCF #2 network element sends third invite response information to the S-CSCF #1 network element, the third invite response information indicating that the direct voice communication is rejected, the S-CSCF #1 network element sends second invite response information to the P-CSCF #1 network element, the second invite response information indicating that the direct voice communication is rejected. After this step, step S429 is directly performed, which specifically refers to step S404, and detailed description is omitted here.

S412: and the P-CSCF #2 network element sends second authentication authorization request information to the PCF network element.

Correspondingly, the PCF network element receives the second authentication authorization request message.

Optionally, the second authentication and authorization request message includes the second direct communication indication message.

In the first implementation manner, if the fifth invite request message in step S411 includes the second direct communication indication message, the second authentication and authorization request message includes the second direct communication indication message.

It should be noted that, if the first network direct communication capability information is not involved in the above steps S402-S403, the second authentication authorization request information includes the second network direct communication capability request information. When the UE1 and the UE2 perform direct voice communication, networks to which the UE1 and the UE2 access may belong to the same network, and therefore, the first network direct communication capability information is the second network direct communication capability information.

It should be noted that the PCF in steps S402-S403 and the PCF in steps S412-S413 may not be one PCF, the PCF in steps S402-S403 is a PCF corresponding to the session of UE1 for transmitting the data of the IMS service, and the PCF in steps S412-S413 is a PCF corresponding to the session of UE2 for transmitting the data of the IMS service.

S413: and the PCF network element sends second authentication authorization response information to the P-CSCF #2 network element.

Correspondingly, the P-CSCF #2 network element receives the second authentication authorization response message.

Optionally, the second authentication authorization response information includes second access type indication information, and since the UE1 accesses the satellite through the satellite access network and the UE2 accesses the satellite through the satellite access network, types of the UE1 and the UE2 accessing the satellite may 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, and details are not repeated here.

Optionally, if the first network direct communication capability information is not involved in steps S402-S403, the second authentication authorization response information includes the second network direct communication capability information. Specifically, refer to step S403. It should be understood that, when UE1 and UE2 perform direct voice communication, the networks to which UE1 and UE2 access may belong to the same network, and therefore, the second network direct communication capability information is the first network direct communication capability information.

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

Accordingly, the UE #2 network element receives the sixth invite request information.

In an implementation manner, if, in the step S411, the fifth invite request message includes the second direct communication indication message, and the second access type indication message included in the second authentication authorization response message in the step S413 indicates that the UE2 does not access through the satellite, then step S414 is not executed again, the P-CSCF #2 network element sends the fifth invite response message to the S-CSCF #2 network element, where the fifth invite response message indicates that the direct voice communication is rejected, and the subsequent S-CSCF #2 network element executes a reject procedure of returning the invite response message to the S-CSCF #2 network element in the step S411, which is not described in detail herein.

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

Accordingly, the P-CSCF #2 network element receives the sixth invite response information.

Optionally, the sixth invitation response message may include second access type indication information, where the second access type indication information indicates that the UE2 accesses the network through the satellite, and specifically, the first access type indication information of step S401 is synchronized. It is noted that the second access type indication information may also indicate other access types, e.g. indicating that the UE2 does not access via satellite.

The other access types specifically indicated in the present application are not limited, and the second access type indication information indicates that the UE2 accesses the network through the satellite without specific description.

Optionally, the sixth invitation response information may further include second media characteristic support information indicating that the UE2 supports the media characteristic for the direct voice communication. It should be noted that the second media characteristic support information may also indicate that the UE2 does not support the media characteristic for direct voice communication, and in a case where no special description is made, the second media characteristic support information indicates that the UE2 supports the media characteristic for direct voice communication. The media characteristics supported by the UE2 may include a voice data codec supported by the UE2 and used for the direct voice communication.

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 the UE2. Since the networks accessed by the UE1 and the UE2 when performing direct voice communication are the same network, the first network direct communication capability information and the second network direct communication capability information are the same.

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

Accordingly, the S-CSCF #2 network element receives the fifth invite response information.

Optionally, the fifth invitation response message includes the second access type information. The second access type information is type information of a satellite accessed by the UE2.

In the first implementation manner, if at least one of the second authentication authorization response information in step S413 and the sixth invitation response information in step S415 includes the second access type indication information, the fifth invitation response information includes the second access type information.

Optionally, the fifth invitation response information includes second media characteristic support information.

In a second implementation manner, if at least one of the second authentication authorization response information in step S413 and the sixth invitation response information in step S415 includes the second access type indication information, and the second access type indication information indicates that the UE2 does not access through the satellite, the fifth invitation response information indicates that the direct voice communication is rejected.

S417: and the S-CSCF #2 network element sends the fourth invitation response information to the I-CSCF #2 network element.

Accordingly, the network element of I-CSCF #2 receives the fourth invite response message.

Optionally, the fourth invitation response information includes one or more of second access type information, second media characteristic support information, second direct communication support information, and second network direct communication capability information (first network direct communication capability information).

In the first implementation manner, if the first direct communication indication information is included in step S408, that is, the preferred scheme described in step S408 is corresponded, the fourth invitation response information includes one or more of the second access type information, the second media characteristic support information, the second direct communication support information, and the second network direct communication capability information (the first network direct communication capability information), and under the scheme, the second access type information is optional.

In the second implementation manner, the fourth invite response information includes second direct communication result indication information indicating that the UE2 accepts or rejects the direct voice communication, and therefore, the fourth invite response information indicates that the direct voice communication is accepted or rejected. Or the acceptance or rejection of the direct voice communication is instructed by the fourth invite response message itself.

In a third implementation manner, if the step S408 includes one or more of the first access type indication information, the first direct communication support information, the first network direct communication capability information, and the first media characteristic support information, that is, if the optional scheme described in the step S408 is included, the fourth invitation response information includes the second direct communication result indication information. If the following conditions are simultaneously satisfied, the S-CSCF #2 network element determines that direct communication is established between UE1 and UE2, and the specific satisfied condition may be:

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

2) If the first media characteristic supporting information of the UE1 and the second media characteristic supporting information of the UE2 are received and both the media characteristics supported by the UE1 and the media characteristics supported by the UE2 support the media characteristics for direct voice communication, in an implementation manner, the media characteristics supported by the UE1 and the media characteristics supported by the UE2 need to be matched;

3) If the first network direct communication capability information and the second network direct communication capability information are received (the first network direct communication capability information is the second network direct communication capability information), indicating that the network accessed by the UE1 and the UE2 supports the direct communication between the satellites;

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

And if any one of the conditions is not met, the S-CSCF #2 network element determines to reject the direct voice communication.

It should be noted that there is a possible scenario that when only partial information is acquired, all conditions are not required to be satisfied, the S-CSCF #2 network element determines to establish direct communication for the UE1 and the UE2, and if only the first access type indication information of the UE1 and the second access type information of the UE2 are present, only 1 needs to be satisfied).

S418: and the network element of the I-CSCF #2 sends third invitation response information to the network element of the S-CSCF # 1.

Correspondingly, the S-CSCF #1 network element receives the third invite response message.

Specifically, the content included in the third invitation response information is the same as that in step S417, and is not described in detail here.

S419: and the S-CSCF #1 network element determines to accept the direct voice communication, namely establishes direct communication between the UE1 and the UE2.

In a first implementation manner, the S-CSCF #1 network element receives the first network direct communication capability information (second network direct communication capability information), and any one or more of access type indication information, direct communication support information, and media characteristic support information of the UE1 and the UE 2; if the 4 conditions in step S417 are simultaneously satisfied, the S-CSCF #1 network element determines to accept the direct voice communication, otherwise, the S-CSCF #1 network element determines to reject the direct voice communication.

It should be understood that the access type indication information of UE1 and UE2 is the first access type indication information and the second access type indication information; the direct communication support information of the UE1 and the UE2 is first direct communication support information and second direct communication support information; the media characteristics support information of UE1 and UE2 is the first media characteristics support information and the second media characteristics support information.

The determination method of S-CSCF #1 synchronizes step S417, which is not described in detail.

In a second implementation, the third invite response message received by the S-CSCF #1 network element indicates acceptance or rejection of direct voice communication.

It should be noted that, reference may be made to the foregoing description for the case of rejecting direct voice communication, and details are not described herein again.

In this embodiment, fig. 4A and fig. 4B belong to the same embodiment flow, the above steps S401 to S409 refer to fig. 4A, and the following steps S420 to S430 refer to fig. 4B.

S420: and the S-CSCF #1 network element sends the second invitation response information to the P-CSCF #1 network element.

Accordingly, the P-CSCF #1 network element receives the second invite response information.

In a first implementation manner, the second invite response message includes QoS requirement information for direct voice communication, where the QoS requirement information refers to information such as QoS identifier or parameter.

In a second implementation manner, the second invite response message indicates that the direct voice communication is accepted, and the specific indication manner is the same as that of step S417.

S421: and the P-CSCF #1 network element sends the direct communication establishment information to the PCF network element.

Accordingly, the PCF network element receives the direct communication setup information.

Optionally, the direct communication setup information includes information of UE1 and information of UE2. Specifically, the direct communication setup information includes IP address information of UE1 and IP address information of UE2, or the direct communication setup information includes identification information of UE1 and identification information of UE2, and the identification information may be general Public user identity (GPSI). It should be noted that in the present application, identification information mentioned in some places may also indicate address information.

Optionally, the direct communication setup information includes direct communication setup indication information indicating that direct voice communication is set up for UE1 and UE2.

Optionally, the direct communication setup information may further include QoS requirement information for direct voice communication.

It should be noted that, after step S421, the PCF network element further needs to send response information to the P-CSCF #2 network element, where the response information is used to confirm receipt, and in order to simplify this step, a flow for the PCF network element to send the response information to the P-CSCF #2 network element is not separately shown in fig. 4B, but a double arrow is used to indicate interaction between the PCF network element and the P-CSCF #2 network element, and step S422 is the same and is not described again.

S422: and the PCF network element sends the direct communication establishment information to the SMF network element.

Accordingly, the SMF network element receives the direct communication setup information.

Optionally, the direct communication setup information includes information of UE1 and information of UE2. Specifically, as in step S421, refer to step S421.

The PCF network element receives the information of the UE1 and the information of the UE2, determines the PDU session identification of the UE1 and the PDU session identification of the UE2 according to the information of the UE1 and the information of the UE2, and includes the identification information in the direct communication establishment information.

Alternatively, the direct communication setup information may include the direct communication setup instruction information described above.

Optionally, the direct communication setup information may include QoS information for direct voice communication. The QoS information synchronization step S421 indicates that the QoS requirement information is the same, or the PCF network element determines the QoS information according to the QoS requirement information of step S421, which may be a change in form, for example.

It should be noted that the direct communication setup information in step S421 and step S422 may be the same information or different information, and is not limited herein.

S423: the SMF network element distributes tunnel information for direct voice communication in the S-UPF1 network element and the S-UPF2 network element.

The S-UPF1 network element is a user plane network element used by the UE1 for the PDU session of the direct voice communication, and the S-UPF2 network element is a user plane network element used by the UE2 for the PDU session of the direct voice communication.

It should be understood that in the present application the S-UPF1 network element and the S-UPF2 network element may be located on two different satellites. The tunnel refers to a tunnel between an S-UPF1 network element and an S-UPF2 network element, and the tunnel is used for transmitting voice data.

In a first implementation manner, the SMF network element receives the information of UE1 and the information of UE2, the SMF network element determines the identifier of the PDU session of UE1 and the identifier of the PDU session of UE2 for direct voice communication according to the information of UE1 and the information of UE2, and the SMF network element allocates tunnel information to the PDU sessions of UE1 and UE2, that is, the tunnel information for direct voice communication in S-UPF1 and S-UPF2, respectively.

In a second implementation manner, the SMF network element receives the PDU session identifier of UE1 and the PDU session identifier of UE2 for direct voice communication, and the SMF network element allocates tunnel information to the PDU sessions of UE1 and UE2.

In a third implementation manner, if the SMF network element receives the direct communication setup instruction information, tunnel information is allocated to the PDU sessions of UE1 and UE2.

S424: and the SMF network element sends the N4 session request information to the S-UPF1 network element.

Accordingly, the S-UPF1 network element receives the N4 session request information.

Specifically, the N4 session request information requests to configure tunnel information for the PDU session for direct voice communication, and the N4 session request information includes QoS information for direct voice communication and tunnel information for direct voice communication in S-UPF1 and S-UPF 2.

S425: and establishing an internal tunnel between the gNB1 and the S-UPF1 network element.

Specifically, after the S-UPF1 network element updates the tunnel information, the gNB1 needs to update the corresponding tunnel information, so as to establish a tunnel between the gNB1 and the S-UPF1 network element.

It should be noted that, in the present application, how to establish a tunnel between a gNB1 network element and an S-UPF1 network element is not limited, and for example, the SMF network element and the gNB1 network element may interact with each other, or the gNB1 network element and the S-UPF1 network element interact with each other to establish a tunnel. Step S425 may also be performed after step S426.

S426: and the S-UPF1 network element sends N4 session response information to the SMF network element, wherein the N4 session response information is used for confirming that the tunnel is configured completely.

S427: and the SMF network element sends the N4 session request information to the S-UPF2 network element.

S428: and establishing an internal tunnel between the gNB2 and the S-UPF2 network element.

S429: and the S-UPF2 network element sends N4 session response information to the SMF network element, wherein the N4 session response information is used for confirming that the tunnel is configured completely.

It is noted that steps S427-S429 are similar to steps S424-426, with the difference that in steps S427-S429 the S-UPF1 network element is replaced by an S-UPF2 network element, and the gNB1 is changed to gNB2. The sequence of executing steps S424-S426 and steps S427-S429 is not specifically limited in this application.

S430: the P-CSCF network element #1 sends the first invite response information to the UE 1.

Accordingly, the UE1 receives the first invite response message indicating acceptance of the direct voice communication.

It is noted that the first invitation response message may also indicate a rejection of the direct voice communication.

In summary, the embodiments shown in fig. 4A-4B introduce that, in a scenario of multiple IM CNs, a CSCF serving UE1 is different from a CSCF serving UE2, a first terminal may determine, by the corresponding CSCF, whether to establish direct voice communication for the first terminal and a second terminal according to access type information, subscription information, capability information supported by a network, and media characteristic information supported by the first terminal and the second terminal, and then an SMF network element establishes a transmission path for the direct voice communication for the first terminal and the second terminal, so that the first terminal and the second terminal may perform direct voice communication through the established transmission path, and it may be avoided that the first terminal and the second terminal transmit voice data through the ground, thereby causing a long voice communication duration.

Based on the communication method provided by the above embodiment, the method of the present application is described in detail below with reference to a specific embodiment. The embodiment mainly realizes the direct voice communication of the terminal through the satellite in a single IM CN scene. In this embodiment, the UE1 and the UE2 may access the network through a corresponding satellite, that is, the UE1 may access the network through a first satellite, the UE2 may access the network through a second satellite, each satellite includes a base station and a UPF network element, and the UE1 and the UE2 are served by a same call control function CSCF network element, which includes a P-CSCF network element, an I-CSCF network element, and an S-CSCF network element. Referring to fig. 5, a specific implementation flow of this embodiment is as follows:

s501: the terminal UE1 sends first invite request information to the P-CSCF #1 network element, the first invite request information requesting communication with the second terminal UE2.

Step S501 may refer to step S401, which is not described in detail here.

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

Step S502 may refer to step S402, which is not described in detail herein.

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

Step S503 may refer to step S403, which is not described in detail herein.

S504: and the P-CSCF #1 network element sends second invitation request information to the S-CSCF #1 network element.

Step S504 may refer to step S404, which is not described in detail here.

S505: and the S-CSCF #1 network element sends subscription data request information to the UDM network element.

Step S505 may refer to step S405, which is not described in detail herein.

S506: and the UDM network element sends subscription data response information to the S-CSCF #1 network element.

Step S506 may refer to step S406, which is not described in detail herein.

It should be noted that the above steps S501 to S506 are substantially the same as the above steps S401 to S406, and the main differences include: the direct communication support information of UE1 in the multi-IM CN scenario of fig. 4A-4B becomes the direct communication support information of UE1 and UE2 in this single IM CN scenario. That is, the subscription data request information requests subscription data of UE1 and UE2 in step S505.

S507: and the S-CSCF #1 network element sends third invitation request information to the UE #2 network element.

It should be noted that, if the access type indication information in step S501 or step S503 indicates that the UE1 accesses the network through the satellite and the network direct communication capability information indicates that the network does not support the direct communication between satellites, the following step S520 is directly performed without performing steps S507-S519. Alternatively, the first and second electrodes may be,

if the access type indication information in step S501 or step S503 indicates that the UE1 accesses the network through the satellite, and the direct communication support information of the UE1 indicates that the UE1 does not support the direct voice communication or the direct communication support information of the UE2 indicates that the UE2 does not support the direct voice communication, steps S507-S519 are no longer executed, and step S520 described below is directly executed.

S508: and the UE2 sends the third invitation response information to the network element of the S-CSCF #1 network element.

Step S508 may refer to step S415, which is not described in detail herein.

S509: the S-CSCF #1 network element determines to accept the direct voice communication.

Step S509 may refer to step S419, which is not described in detail herein.

S510: and the S-CSCF #1 network element sends the second invitation response information to the P-CSCF #1 network element.

Step S509 may refer to step S420, which is not described in detail herein.

S511: and the P-CSCF #1 network element sends the direct communication establishment information to the PCF network element.

Step S511 can refer to step S421, and is not described in detail here.

S512: and the PCF network element sends the direct communication establishment information to the SMF network element.

Step S512 may refer to step S422, which is not described herein in detail.

S513: the SMF network element distributes tunnel information for direct voice communication in the S-UPF1 network element and the S-UPF2 network element.

Step S513 may refer to step S423 described above, and details are not described herein again.

S514: and the SMF network element sends the N4 session request information to the S-UPF1 network element.

Step S514 may refer to step S424, which is not described herein in detail.

S515: and establishing an internal tunnel between the gNB1 and the S-UPF1 network element.

Step S515 may refer to step S425, which is not described in detail herein.

S516: and the S-UPF1 network element sends N4 session response information to the SMF network element, wherein the N4 session response information is used for confirming that the tunnel is configured completely.

Step S516 may refer to step S426, which is not described in detail herein.

S517: and the SMF network element sends the N4 session request information to the S-UPF2 network element.

Step S517 may refer to step S427 described above, and will not be described in detail here.

S518: and establishing an internal tunnel between the gNB2 and the S-UPF2 network element.

Step S518 may refer to step S428 described above, and will not be described in detail here.

S519: and the S-UPF2 network element sends N4 session response information to the SMF network element, wherein the N4 session response information is used for confirming that the tunnel is configured completely.

Step S519 may refer to step S429, which is not described in detail here.

S520: the P-CSCF network element #1 sends the first invite response information to the UE 1.

Step S520 may refer to step S430, which is not described in detail herein.

It should be noted that the above steps S509-S520 are substantially the same as the steps S419-S430 of the multi-IM CN scenario flow, and the main differences include: in step S519, the S-CSCF #1 network element does not receive the invite response message indicating acceptance or rejection of the direct voice communication.

To sum up, the embodiment shown in fig. 5 introduces that in a single IM CN scenario, the CSCF serving the UE1 is the same as the CSCF serving the UE2, the CSCF of the first terminal may determine whether to establish direct voice communication between the first terminal and the second terminal according to the access type information, the subscription information, the capability information supported by the network, and the media characteristic information supported by the first terminal and the second terminal, and then the SMF network element establishes a transmission path for the direct voice communication between the first terminal and the second terminal, so that the first terminal and the second terminal may perform direct voice communication through the established transmission path, and it may be avoided that the voice data transmitted by the first terminal and the second terminal passes through the ground, thereby reducing the duration of the voice communication between the first terminal and the second terminal, and improving user experience to a greater extent.

Based on the same technical concept, the embodiment of the present application provides a communication apparatus, where the apparatus may include a module or a unit that performs one-to-one correspondence of the method/operation/step/action described in the call session control function network element in the first method embodiment, and the module or the unit may be a hardware circuit, or may also be software, or may be implemented by combining a hardware circuit with software. The device may have a structure as shown in fig. 6.

As shown in fig. 6, the communication device 600 may include a receiving unit 601, a processing unit 602, and a transmitting unit 603, which are described in detail below.

The receiving unit 601 receives first invitation request information of a first terminal, where the first invitation request information requests to communicate with a second terminal; the receiving unit 601 is further configured to obtain first access information and second access information, where the first access information indicates that the first terminal accesses a network through a satellite, and the second access information indicates that the second terminal accesses the network through the satellite; the processing unit 602 is configured to determine, according to 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 data of an internet protocol multimedia subsystem (IMS) service between the first terminal and the second terminal between a first satellite of the first terminal access network and a second satellite of the second terminal access network; the sending unit 603 sends a first request message to a first network element, where the first request message indicates that the first terminal and the second terminal perform direct communication.

In a possible implementation manner, when acquiring the first access information, the receiving unit 601 may specifically be configured to: and acquiring the first access information from the first terminal or a policy control function network element corresponding to the session of the first terminal, wherein the session of the first terminal is used for transmitting the data of the IMS service.

In a possible implementation manner, when acquiring the second access information, the receiving unit may specifically be configured to: and acquiring second access information from the second terminal or a policy control function network element corresponding to the 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 for transmitting the data of the IMS service.

In a possible implementation manner, the receiving unit 601 may further be configured to: before the processing unit 602 determines to establish direct communication for the first terminal and the second terminal according to the first access information and the second access information,

acquiring first network direct connection capability information, wherein the first network direct connection capability information indicates that the first network supports the direct communication, and the first terminal and the second terminal are accessed through the first network.

In a possible implementation manner, the receiving unit 601 may further be configured to: before the processing unit 602 determines to establish direct communication between the first terminal and the second terminal according to the first access information and the second access information, the method further includes: and receiving first direct communication signature information and second direct communication signature information, wherein the first direct communication signature information indicates that the first terminal is allowed to directly communicate, and the second direct communication signature information indicates that the second terminal is allowed to directly communicate.

In a possible implementation manner, the receiving unit 601 may further be configured to: before the processing unit 602 determines to establish direct communication between the first terminal and the second terminal according to the first access information and the second access information, obtain first media characteristic support information and second media characteristic support information, where the first media characteristic support information indicates a media characteristic used by the first terminal for the IMS service, and the second media characteristic support information indicates a media characteristic used by the second terminal for the IMS service.

In a possible implementation, the first invite request information includes direct communication request indication information indicating that the first terminal desires to perform the direct communication with the second terminal.

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

In a possible implementation, the first request information comprises quality of service, qoS, information for the direct communication.

In a possible implementation manner, the sending unit 603 is further configured to: and sending first invitation response information to the first terminal, wherein the first invitation response information indicates that the first terminal is accepted to carry out the direct communication with the second terminal.

Based on the same inventive concept, an embodiment of the present application further provides a communication device, where the communication device executes the steps executed by the call session control function network element in the methods provided in the embodiments corresponding to fig. 3A, fig. 3B, fig. 4A to fig. 4B, and fig. 5, and may be the same device as the communication apparatus 600 shown in fig. 6. Referring to fig. 7, the communication device 700 includes: a transceiver 701, a processor 702, and a memory 703. Wherein the transceiver 701, the processor 702 and the memory 703 are connected by a bus 704 for enabling data exchange.

It is to be understood that the transceiver 701 in this communication device 700 comprises, among other things, the functions of the transmitting unit 601 and the receiving unit 603 in the communication apparatus 600 described above. The transceiver 701 is configured to support the communication apparatus 700 to receive and transmit information with a network element and a terminal in a core network in the foregoing embodiments, where the network element of the core network may include a policy control network element, a unified data management network element, and the like. The memory 703 is used to store program codes and data for the communication device 700. The processor 702 is configured to invoke the program codes and data stored in the memory 703 and to perform the processing procedures of the methods shown in fig. 3A-3B, 4A-4B, and 5 involving the call session control function network element and/or other procedures for the techniques described herein.

In addition, the communications apparatus 700 can also include other interfaces, such as a fiber link interface, an ethernet interface, a microwave link interface, a copper wire interface, etc., for enabling interaction of the communications apparatus 700 with other devices (e.g., access network equipment and UPF on satellite, core network elements on the ground, etc.).

Alternatively, the processor 702 may be a central processor, ASIC, FPGA, or CPLD.

Fig. 7 shows a communication device 700 that includes only one transceiver 701, one processor 702, and one memory 703. In practical implementation, the number of the transceiver 701, the processor 702 and the memory 703 may be one or more.

Based on the same concept as the method embodiment, the embodiment of the present application further provides a computer-readable storage medium, on which some instructions are stored, and when the instructions are called by a computer and executed, the instructions may cause the computer to perform the method involved in any one of the possible designs of the method embodiment and the method embodiment. In the embodiment of the present application, the computer-readable storage medium is not limited, and may be, for example, a RAM (random-access memory), a ROM (read-only memory), and the like.

Based on the same concept as the above method embodiments, the present application also provides a computer program product, which when called by a computer can perform the method as referred to in the method embodiments and any possible design of the above method embodiments.

Based on the same concept as the above method embodiments, the present application also provides a chip, which may include a processor and an interface circuit, for implementing the method as referred to in any one of the possible implementations of the above method embodiments, wherein "coupled" means that two components are directly or indirectly joined to each other, which may be fixed or movable, which may allow flowing liquid, electric, electrical or other types of signals to be communicated between the two components.

It is to be noted that at least one of the embodiments of the present application includes one or more; wherein a plurality means greater than or equal to two. In addition, it is to be understood that the terms first, second, etc. in the description of the present application are used for distinguishing between the descriptions and not necessarily for describing a sequential or chronological order.

The terminology used in the following examples is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of the present application and the appended claims, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, such as "one or more", unless the context clearly indicates otherwise. It should also be understood that in the embodiments of the present application, "one or more" means one or more than two (including two); "and/or" describes the association relationship of the associated objects, indicating that three relationships may exist; for example, a and/or B, may represent: a exists singly, A and B exist simultaneously, and B exists singly, wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather "one or more but not all embodiments" unless specifically stated otherwise. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless expressly specified otherwise.

The division of the modules in the embodiments of the present application is schematic, and only one logical function division is provided, and in actual implementation, there may be another division manner, and in addition, each functional module in each embodiment of the present application may be integrated in one processor, may also exist alone physically, or may also be integrated in one module by two or more modules. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode.

Through the above description of the embodiments, those skilled in the art will clearly understand that the embodiments of the present application can be implemented by hardware, firmware, or a combination thereof. When implemented in software, the functions described above may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. Taking this as an example but not limiting: the computer-readable medium may include RAM, ROM, an Electrically Erasable Programmable Read Only Memory (EEPROM), a compact disc read-Only memory (CD-ROM) or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Furthermore, the method is simple. Any connection is properly termed a computer-readable medium. For example, if software is transmitted from a website, a server, or other remote source using a coaxial cable, a fiber optic cable, a twisted pair, a Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, the coaxial cable, the fiber optic cable, the twisted pair, the DSL, or the wireless technologies such as infrared, radio, and microwave are included in the fixation of the medium. Disk and disc, as used in the description of the embodiments, includes Compact Disc (CD), laser disc, optical disc, digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

In summary, the above description is only an example of the present application, and is not intended to limit the scope of the present application. Any modifications, equivalents, improvements and the like made in accordance with the disclosure of the present application are intended to be included within the scope of the present application.

Claims

1. A method of communication, comprising:

a call session control function network element receives first invitation request information of a first terminal, wherein the first invitation request information requests to communicate with a second terminal;

the call session control function network element acquires first access information and second access information, wherein the first access information indicates that the first terminal accesses a network through a satellite, and the second access information indicates that the second terminal accesses the network through the satellite;

the call session control function network element determines to establish direct communication for the first terminal and the second terminal according to the first access information and the second access information; the direct communication refers to the direct transmission of data of an internet protocol multimedia subsystem (IMS) service between the first terminal and the second terminal between a first satellite of the first terminal access network and a second satellite of the second terminal access network;

and the call session control function network element sends first request information to a first network element, wherein the first request information indicates that the first terminal and the second terminal are in direct communication.

2. The method of claim 1, wherein the obtaining the first access information by the call session control function network element comprises:

the call session control function network element obtains the first access information from the first terminal or a policy control function network element corresponding to the session of the first terminal, where the session of the first terminal is used to transmit data of the IMS service.

3. The method of claim 1, wherein the obtaining the second access information by the call session control function network element comprises:

4. The method according to any of claims 1-3, wherein the determining, by the call session control function network element, before establishing the direct communication for the first terminal and the second terminal according to the first access information and the second access information, further comprises:

the call session control function network element obtains first network direct connection capability information, the first network direct connection capability information indicates that the first network supports the direct communication, and the first terminal and the second terminal are accessed through the first network.

5. The method according to any of claims 1-3, wherein the determining, by the call session control function network element, before establishing the direct communication for the first terminal and the second terminal according to the first access information and the second access information, further comprises:

the call session control function network element receives first direct communication signature information and second direct communication subscription information, wherein the first direct communication signature information indicates that the first terminal is allowed to directly communicate, and the second direct communication subscription information indicates that the second terminal is allowed to directly communicate.

6. The method according to any of claims 1-3, wherein the determining, by the call session control function network element, before establishing the direct communication for the first terminal and the second terminal according to the first access information and the second access information, further comprises:

the call session control function network element obtains first media characteristic support information and second media characteristic support information, wherein 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.

7. The method of claim 1, wherein the first invite request information comprises direct communication request indication information indicating that the first terminal desires the direct communication with the second terminal.

8. The method according to any of claims 1-6, wherein the first request information comprises identification information of the first terminal and identification information of the second terminal.

9. The method according to any of claims 1-6, wherein the first request information comprises quality of service, qoS, information for the direct communication.

10. The method according to any one of claims 1-9, further comprising:

and the call session control function network element sends first invitation response information to the first terminal, wherein the first invitation response information indicates that the first terminal and the second terminal are accepted to carry out the direct communication.

11. A call session control function network element, comprising: a receiving unit, a processing unit and a sending unit;

the receiving unit is configured to receive first invitation request information of a first terminal, where the first invitation request information requests to communicate with a second terminal;

the receiving unit is further configured to obtain first access information and second access information, where the first access information indicates that the first terminal accesses the network through a satellite, and the second access information indicates that the second terminal accesses the network through the satellite;

the processing unit is configured to determine, according to 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 data of an internet protocol multimedia subsystem (IMS) service between the first terminal and the second terminal between a first satellite of the first terminal access network and a second satellite of the second terminal access network;

the sending unit is configured to send first request information to a first network element, where the first request information indicates that direct communication is performed between the first terminal and the second terminal.

12. The network element of claim 11, wherein, when acquiring the first access information, the receiving unit is specifically configured to: and acquiring the first access information from the first terminal or a policy control function network element corresponding to the session of the first terminal, wherein the session of the first terminal is used for transmitting the data of the IMS service.

13. The network element of claim 11, wherein, when acquiring the second access information, the receiving unit is specifically configured to: and acquiring second access information from the second terminal or a policy control function network element corresponding to the 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 for transmitting the data of the IMS service.

14. The call session control function network element of any of claims 11-13, wherein the receiving unit is further configured to: and before the processing unit determines to establish direct communication between the first terminal and the second terminal according to the first access information and the second access information, acquiring first network direct communication capability information, wherein the first network direct communication capability information indicates that the first network supports the direct communication, and the first terminal and the second terminal are accessed through the first network.

15. The call session control function network element of any of claims 11-13, wherein the receiving unit is further configured to: before the processing unit determines to establish direct communication between the first terminal and the second terminal according to the first access information and the second access information, receiving first direct communication signature information and second direct communication subscription information, wherein the first direct communication signature information indicates that the first terminal is allowed to directly communicate, and the second direct communication subscription information indicates that the second terminal is allowed to directly communicate.

16. The call session control function network element of any of claims 11-13, wherein the receiving unit is further configured to: before the processing unit determines to establish direct communication between the first terminal and the second terminal according to the first access information and the second access information, first media characteristic support information and second media characteristic support information are acquired, wherein the first media characteristic support information indicates a media characteristic used by the first terminal for the IMS service, and the second media characteristic support information indicates a media characteristic used by the second terminal for the IMS service.

17. The call session control function network element of claim 11, wherein the first invite request information comprises direct communication request indication information indicating that the first terminal desires to communicate directly with the second terminal.

18. A call session control function network element according to any of claims 11-16, wherein the first request information comprises identification information of the first terminal and identification information of the second terminal.

19. A call session control function network element according to any of claims 11-16, wherein the first request information comprises quality of service, qoS, information for the direct communication.

20. The call session control function network element according to any of claims 11-19, wherein the sending unit is further configured to: and sending first invitation response information to the first terminal, wherein the first invitation response information indicates that the first terminal is accepted to carry out the direct communication with the second terminal.

21. A non-transitory computer-readable storage medium storing a computer program which is loaded by a processor to perform the method according to any one of claims 1-10.