Communication method and apparatus

Abstract

A communication method and apparatus, which are used for optimizing satellite-transmission-based communication between terminal devices. The communication method comprises: a second network element receiving a first request from a first network element, and sending, on the basis of the first request, first indication information to the first network element, wherein the first request is used for requesting whether a first terminal device and a second terminal device communicates by means of satellite transmission; the first terminal device accesses a first satellite, and the second terminal device accesses a second satellite; and the first indication information is used for indicating that the first terminal device and the second terminal device communicate by means of satellite transmission, or the first indication information is used for indicating that the first terminal device and the second terminal device do not communicate by means of satellite transmission. In this way, whether the first terminal device and the second terminal device communicate by means of satellite transmission can be evaluated by the second network element, such that a relatively suitable communication mode between the first terminal device and the second terminal device can be accurately determined in each scenario, and the communication efficiency is improved.

Description

Communication method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on April 3, 2024, with application number 202410408727.7 and application name "A Communication Method and Device", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a communication method and device. Background Art

[0004] The 3rd Generation Partnership Project (3GPP) proposes that when a terminal device is connected to a satellite, service data between two terminals can be transmitted locally on the satellite or between satellites. For example, user-plane traffic, such as voice traffic, between terminals can be transmitted using inter-satellite communication (i.e., terminal 1-satellite 1-satellite 2-terminal 2), without requiring a detour via a terrestrial path.

[0005] However, as medium-, high-, and low-orbit satellites move relative to ground coverage, the access of terminal devices to satellites becomes uncontrollable. There is no guarantee that two terminal devices will always be covered by the same satellite, or that there will be an inter-satellite link or inter-satellite route between any two satellites at any time. These scenarios may affect communications between terminal devices using satellite transmission. Currently, no solutions have been proposed to address the impact of these scenarios, resulting in doubts about communication reliability or reduced communication efficiency.

[0006] Therefore, how to optimize satellite transmission communication between terminal devices in various scenarios is an urgent problem to be solved. Summary of the Invention

[0007] Embodiments of the present application provide a communication method and apparatus for optimizing communication between terminal devices using satellite transmission.

[0008] In a first aspect, the present application provides a communication method, which can be applied to a second network element, a processor, a chip, a chip system, or a functional module in the second network element. Taking application to the second network element as an example, the method may include: the second network element receiving a first request from a first network element, and sending first indication information to the first network element based on the first request, wherein the first request is used to request whether a first terminal device and a second terminal device communicate using a satellite transmission method; the first terminal device accesses a first satellite, and the second terminal device accesses a second satellite; the first indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method, or the first indication information is used to indicate that the first terminal device and the second terminal device do not communicate using a satellite transmission method.

[0009] Based on the above communication method, the second network element can evaluate whether the first terminal device and the second terminal device communicate using satellite transmission, so that the more appropriate communication method between the first terminal device and the second terminal device can be accurately determined in each scenario, thereby improving communication efficiency.

[0010] In one possible design, the first request may include one or more of the following: identification information of the first satellite, identification information of the second satellite, information of the first terminal device, information of the second terminal device, or information requiring communication between the first terminal device and the second terminal device using satellite transmission. This allows the second network element to determine the first indication information based on the information in the first request.

[0011] In one possible design, the identification information of the first satellite may be an identifier of a first user plane function network element, an identifier of a first access network device, an identifier of a first access gateway, an identifier of the first satellite, an identifier of a first sector (i.e., an identifier of a first cell), or an identifier of a first beam deployed on the first satellite. At least one of the first user plane function network element, the first access network device, and the first access gateway is located on the first satellite and provides services to the first terminal device. The first sector (or first cell) is a cell corresponding to the first access network device on the first satellite. The identification information of the second satellite may be an identifier of a second user plane function network element, an identifier of a second access network device, an identifier of a second access gateway, an identifier of the second satellite, an identifier of a second sector (i.e., an identifier of a second cell), or an identifier of a second beam deployed on the second satellite. At least one of the second user plane function network element, the second access network device, and the second access gateway is located on the second satellite and provides services to the second terminal device. The second sector (or second cell) is a cell corresponding to the second access network device on the second satellite. This allows the second network element to accurately determine the first indication information.

[0012] In one possible design, the information of the first terminal device includes one or more of the following: an identifier of the first terminal device, an Internet Protocol (IP) address of the first terminal device, location information of the first terminal device, a motion trajectory of the first terminal device, or identification information of the first satellite; the information of the second terminal device includes one or more of the following: an identifier of the second terminal device, an IP address of the second terminal device, location information of the second terminal device, a motion trajectory of the second terminal device, or identification information of the second satellite. This allows the second network element to accurately determine the first indication information.

[0013] In one possible design, the second network element sends first indication information to the first network element based on the first request. The method may be: the second network element determines the first indication information based on the first request and a first principle, and sends the first indication information to the first network element. In this way, the second network element can accurately determine whether satellite transmission is used for communication between the first terminal device and the second terminal device based on the information in the first request and the first principle.

[0014] In one possible design, the first principle may include one or more of the following: if the delay of communication between the first terminal device and the second terminal device using satellite transmission is less than the delay of communication between the first terminal device and the second terminal device using ground transmission, then the first terminal device and the second terminal device use satellite transmission for communication; or, the number of path nodes of communication between the first terminal device and the second terminal device using satellite transmission is less than the number of path nodes of communication between the first terminal device and the second terminal device using ground transmission, then the first terminal device and the second terminal device use satellite transmission for communication; or, the delay of communication between the first terminal device and the second terminal device using satellite transmission is less than the number of path nodes of communication between the first terminal device and the second terminal device using ground transmission. If the delay of communication using ground transmission mode is greater than or equal to the first delay, and the running directions of the first satellite and the second satellite are consistent, and the delay of communication between the first terminal device and the second terminal device using satellite transmission mode is greater than or equal to the first delay, then the first terminal device and the second terminal device communicate using satellite transmission mode; or, the number of path nodes of communication between the first terminal device and the second terminal device using satellite transmission mode is less than the number of path nodes of communication between the first terminal device and the second terminal device using ground transmission mode, and the running directions of the first satellite and the second satellite are consistent, and the number of path nodes of communication between the first terminal device and the second terminal device using satellite transmission mode is less than or equal to the first node number threshold, then the first terminal device and the second terminal device communicate using satellite transmission mode. Based on the first principle, the same principle can be used in various scenarios to evaluate whether satellite transmission mode is used for communication between the first terminal device and the second terminal device to improve communication efficiency.

[0015] In one possible design, the second network element may further send information about a first transmission path to the first network element, where the first transmission path is used for communication between the first terminal device and the second terminal device using satellite transmission. In this way, the second network element can provide a more optimal path and reduce communication latency.

[0016] In one possible design, the first transmission path is determined when the transmission delay between the first user plane function network element and the second user plane function network element is greater than the transmission delay between the third user plane function network element and the fourth user plane function network element, wherein the first user plane function network element is located on the first satellite, the second user plane function network element is located on the second satellite, the third user plane function network element is located on the third satellite, and the fourth user plane function network element is located on the fourth satellite. Alternatively, the first transmission path is determined when the transmission delay between the first user plane function network element, the first access gateway, the second access gateway, and the second user plane function network element is greater than the transmission delay between the third user plane function network element, the third access gateway, the fourth access gateway, and the fourth user plane function network element, wherein the first user plane function network element and the first access gateway are located on the first satellite, the second user plane function network element and the second access gateway are located on the second satellite, the third user plane function network element and the third access gateway are located on the third satellite, and the fourth user plane function network element and the fourth access gateway are located on the fourth satellite. In this way, the second network element can determine a more optimal path and reduce communication delay.

[0017] In one possible design, the information of the first transmission path includes: an identifier of a third user plane function network element and an identifier of a fourth user plane function network element; wherein the third user plane function network element is located on a third satellite, and the fourth user plane function network element is located on a fourth satellite; or, the information of the first transmission path includes: an identifier of the third user plane function network element and an identifier of the fourth user plane function network element, and an identifier of a third access gateway and an identifier of a fourth access gateway; wherein the third user plane function network element and the third access gateway are located on the third satellite, and the fourth user plane function network element and the fourth access gateway are located on the fourth satellite. In this way, the first network element can obtain information about a more optimal path, thereby accurately establishing a transmission path.

[0018] In one possible design, the first network element is a session management function network element, a policy control function network element, or a proxy call session control function network element. This can flexibly trigger the second network element to determine the communication mode.

[0019] In a second aspect, the present application provides a communication method, which can be applied to a first network element, a processor, a chip, a chip system, or a functional module in the first network element. Taking application to the first network element as an example, the method may include: the first network element sends a first request to a second network element, and receives first indication information from the second network element. The first request is used to request whether a first terminal device and a second terminal device communicate using a satellite transmission method; the first terminal device accesses a first satellite, and the second terminal device accesses a second satellite; the first indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method, or the first indication information is used to indicate that the first terminal device and the second terminal device do not communicate using a satellite transmission method.

[0020] Based on the above communication method, the second network element can evaluate whether the first terminal device and the second terminal device communicate using satellite transmission, so that the more appropriate communication method between the first terminal device and the second terminal device can be accurately determined in each scenario, thereby improving communication efficiency.

[0021] In one possible design, the first network element is a session management function network element. When the first indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission mode, the first network element sends the flow rules for the first terminal device and the second terminal device to the first user plane function network element and the second user plane function network element. The first user plane function network element is located on the first satellite, and the second user plane function network element is located on the second satellite. And / or, when the first indication information is used to indicate that the first terminal device and the second terminal device do not communicate using a satellite transmission mode, the first network element sends the flow rules for the first terminal device and the second terminal device to a user plane function network element located on the ground. In this way, the session management function network element can execute the corresponding data transmission process based on the different communication modes indicated by the second network element.

[0022] In one possible design, the first request may include one or more of the following: identification information of the first satellite, identification information of the second satellite, information of the first terminal device, information of the second terminal device, or information requiring communication between the first terminal device and the second terminal device using satellite transmission. This allows the second network element to determine the first indication information based on the information in the first request.

[0023] In one possible design, the identification information of the first satellite may be an identifier of a first user plane function network element, an identifier of a first access network device, an identifier of a first access gateway, an identifier of the first satellite, an identifier of a first sector (which may also be understood as an identifier of a first cell), or an identifier of a first beam deployed on the first satellite. At least one of the first user plane function network element, the first access network device, and the first access gateway is located on the first satellite and provides services to the first terminal device. The first sector (or first cell) is the cell corresponding to the first access network device on the first satellite. The identification information of the second satellite may be an identifier of a second user plane function network element, an identifier of a second access network device, an identifier of a second access gateway, an identifier of the second satellite, an identifier of a second sector (which may also be understood as an identifier of a second cell), or an identifier of a second beam deployed on the second satellite. At least one of the second user plane function network element, the second access network device, and the second access gateway is located on the second satellite and provides services to the second terminal device. The second sector (or second cell) is the cell corresponding to the second access network device on the second satellite. This allows the second network element to accurately determine the first indication information.

[0024] In one possible design, the information of the first terminal device may include one or more of the following: the identifier of the first terminal device, the IP address of the first terminal device, the location information of the first terminal device, the movement trajectory of the first terminal device, or the identification information of the first satellite; the information of the second terminal device may include one or more of the following: the identifier of the second terminal device, the IP address of the second terminal device, the location information of the second terminal device, the movement trajectory of the second terminal device, or the identification information of the second satellite. This allows the second network element to accurately determine the first indication information.

[0025] In one possible design, the first network element is a session management function network element. When the first indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method, the first network element sends second indication information to the proxy call session control function network element via the policy control function network element. The second indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method. In this way, the proxy call session control function network element is informed of the data transmission method between the first terminal device and the second terminal device.

[0026] In one possible design, the first network element is a session management function network element. When the first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, the first network element establishes a tunnel between the first satellite and the second satellite. Subsequently, the first terminal device and the second terminal device communicate using satellite transmission via the tunnel between the first satellite and the second satellite.

[0027] In one possible design, the tunnel between the first satellite and the second satellite is a tunnel between a first user plane functional network element on the first satellite and a second user plane functional network element on the second satellite.

[0028] In one possible design, the first network element is a session management function network element, and when the first indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method, the first network element sends a flow rule between the first terminal device and the second terminal device to the first access gateway and the second access gateway. In this way, the first terminal device and the second terminal device can subsequently communicate using a satellite transmission method.

[0029] In one possible design, the first network element receives the identifier of the first access gateway and the identifier of the second access gateway from the proxy call session control function network element or the policy control function network element; further, the first network element sends the flow rules between the first terminal device and the second terminal device to the first access gateway and the second access gateway. The method may be: the first network element sends the flow rules between the first terminal device and the second terminal device to the first access gateway based on the identifier of the first access gateway; the first network element sends the flow rules between the first terminal device and the second terminal device to the second access gateway based on the identifier of the second access gateway. In this way, the flow rules between the first terminal device and the second terminal device can be accurately sent to the first access gateway and the second access gateway respectively.

[0030] In one possible design, the first network element receives information about a first transmission path from the second network element, where the first transmission path is used for communication between the first terminal device and the second terminal device using satellite transmission. In this way, the second network element can send information about a more suitable transmission path to the first network element.

[0031] In one possible design, the first network element is a session management function network element, and the information of the first transmission path includes an identifier of a third user plane function network element and an identifier of a fourth user plane function network element, wherein the third user plane function network element is located on a third satellite, and the fourth user plane function network element is located on a fourth satellite. When the first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, the first network element establishes a tunnel between the third satellite and the fourth satellite based on the information of the first transmission path. In this way, the first terminal device and the second terminal device can subsequently communicate using satellite transmission based on the first transmission path.

[0032] In one possible design, the tunnel between the third satellite and the fourth satellite is a tunnel between a third user plane functional network element on the third satellite and a fourth user plane functional network element on the fourth satellite.

[0033] In one possible design, the first network element is a session management function network element, and the information about the first transmission path includes: an identifier of a third user plane function network element, an identifier of a fourth user plane function network element, and an identifier of a third access gateway, and an identifier of a fourth access gateway; wherein the third user plane function network element and the third access gateway are located on the third satellite, and the fourth user plane function network element and the fourth access gateway are located on the fourth satellite; when the first indication information is used to indicate that satellite transmission is used for communication between the first terminal device and the second terminal device, the first network element requests the proxy call session control function network element to adopt the first transmission path based on the information about the first transmission path; the first network element determines whether to adopt the first transmission path based on the proxy call session control function network element's response to the request. Thus, after the second network element updates the transmission path, the session management function network element can confirm through the proxy call session control function network element whether the updated path is adoptable.

[0034] In one possible design, the first network element requests the proxy call session control function (PCSCF) network element to adopt the first transmission path based on information about the first transmission path. This may be done by: the first network element sends the identifier of the third access gateway and the identifier of the fourth access gateway to the PCSCF network element; and accordingly, the first network element determines whether to adopt the first transmission path based on the PCSCF network element's response to the request. This may be done by: if the first network element receives the identifier of the third access gateway and the identifier of the fourth access gateway from the PCSCF network element, then the first network element determines to adopt the first transmission path; and / or if the first network element receives the identifier of an access gateway other than the identifier of the third access gateway and the identifier of the fourth access gateway from the PCSCF network element, then the first network element determines not to adopt the first transmission path. In this way, the first network element can accurately determine whether the first transmission path is adoptable through the PCSCF network element.

[0035] In one possible design, when the first network element determines not to use the first transmission path, the first network element sends a second request to the second network element, where the second request is used to request whether the first terminal device and the second terminal device communicate using satellite transmission. The first network element receives third indication information from the second network element, where the third indication information is used to indicate whether the first terminal device and the second terminal device communicate using satellite transmission, or the third indication information is used to indicate whether the first terminal device and the second terminal device communicate using satellite transmission. In this way, if the transmission path provided by the second network element cannot be used, the first network element can re-request the second network element to determine whether the first terminal device and the second terminal device communicate using satellite transmission.

[0036] In one possible design, the first network element is a proxy call session control function network element, and the information of the first transmission path includes an identifier of a third user plane function network element, an identifier of a fourth user plane function network element, and an identifier of a third access gateway and an identifier of a fourth access gateway, wherein the third user plane function network element and the third access gateway are located on a third satellite, and the fourth user plane function network element and the fourth access gateway are located on a fourth satellite; when the first indication information is used to indicate that satellite transmission is used for communication between the first terminal device and the second terminal device, the method may further include: when the load of the third access gateway and the fourth access gateway are both less than or equal to a first load threshold, the first network element sending the identifier of the third access gateway, the identifier of the fourth access gateway, and the first indication information to the session management function network element; or, when the load of at least one of the third access gateway and the fourth access gateway is greater than the first load threshold, the first network element sending a third request to the second network element, the third request being used to request whether satellite transmission is used for communication between the first terminal device and the second terminal device. In this way, the proxy call session control function network element can evaluate whether the first transmission path provided by the second network element is adoptable, and when the first transmission path is adoptable, notify the session management function network element to adopt it; when the first transmission path is not adoptable, re-request the second network element to determine whether the first terminal device and the second terminal device communicate using satellite transmission.

[0037] In one possible design, the first network element is a proxy call session control function network element or a policy control function network element, and the first network element sends the first indication information to the session management function network element, so that the session management function network element can execute subsequent corresponding communication processes based on the first indication information.

[0038] In one possible design, when satellite switching occurs between the first terminal device and / or the second terminal device, the first network element sends a fourth request to the second network element, the fourth request being used to request whether satellite transmission is used for communication between the first terminal device and the second terminal device; the first network element receives fourth indication information from the second network element, the fourth indication information being used to indicate that satellite transmission is used for communication between the first terminal device and the second terminal device, or to indicate that satellite transmission is not used for communication between the first terminal device and the second terminal device. In this way, in a scenario where satellite switching occurs and the current transmission path between the first terminal device and the second terminal device is unusable, the first network element can re-request the second network element to determine whether satellite transmission is used for communication between the first terminal device and the second terminal device.

[0039] In one possible design, the first network element is a session management function network element. When the fourth indication information is used to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission, the first network element deletes the tunnel between the first satellite and the second satellite. In this way, when the first terminal device and the second terminal device previously communicated using satellite transmission, the original tunnel is released to save overhead.

[0040] In one possible design, the first network element is a session management function network element. When the fourth indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, and an access gateway is deployed on the target satellite of the terminal device undergoing satellite handover, the first network element sends a handover indication to the proxy call session control function network element, where the handover indication is used to indicate a path handover between the first terminal device and the second terminal device. This notifies the proxy call session control function network element of the change in the path between the first terminal device and the second terminal device, so that the proxy call session control function network element can re-trigger the voice call process.

[0041] In a third aspect, the present application provides a communication method that can be applied to a proxy call session control function network element, a processor, chip, chip system, or functional module in the proxy call session control function network element. The method may include: determining a first target access gateway and a second target access gateway, and sending an identifier of the first target access gateway and an identifier of the second target access gateway to a session management function network element. The first target access gateway and the second target access gateway are used for communication between a first terminal device and a second terminal device using satellite transmission; the first terminal device accesses a first satellite, and the second terminal device accesses a second satellite.

[0042] Through the above method, in a scenario where an access gateway is deployed on a satellite, a target access gateway that can be used for communication between a first terminal device and a second terminal device using satellite transmission can be decided, and an identifier of the target access gateway can be sent to a session management function network element so that the session management function network element determines whether to use the target access gateway to realize subsequent data transmission between the first terminal device and the second terminal device.

[0043] In one possible design, the method for determining the first target access gateway and the second target access gateway may include: determining the first target access gateway and the second target access gateway based on ephemeris information and information about the first terminal device and the second terminal device; or obtaining an identifier of the first target access gateway and an identifier of the second target access gateway from an evaluation network element. In this way, the first target access gateway and the second target access gateway can be accurately determined.

[0044] In one possible design, second indication information is received from the session management function network element, where the second indication information is used to indicate that satellite transmission is used for communication between the first terminal device and the second terminal device. Furthermore, the method for determining the first target access gateway and the second target access gateway may be: if the loads of the first access gateway and the second access gateway are both less than or equal to a first load threshold, then determining the first target access gateway as the first access gateway and the second target access gateway as the second access gateway based on the second indication information; wherein the first access gateway is located on the first satellite and the second access gateway is located on the second satellite. In this way, the first target access gateway and the second target access gateway can be accurately determined.

[0045] In one possible design, an identifier of a third access gateway and an identifier of a fourth access gateway are received from the session management function network element, where the third access gateway is located on a third satellite and the fourth access gateway is located on a fourth satellite. Furthermore, the method for determining the first target access gateway and the second target access gateway may be: if the loads of the third access gateway and the fourth access gateway are both less than or equal to a first load threshold, then determining the first target access gateway as the third access gateway and the second target access gateway as the fourth access gateway. In this way, the first target access gateway and the second target access gateway can be accurately determined.

[0046] In one possible design, a switching indication is received from the session management function network element, the switching indication being used to instruct a path switch between the first terminal device and the second terminal device; and first information is sent to the first terminal device or the second terminal device based on the switching indication, the first information being used to initiate a voice call process. This ensures service continuity after the satellite handover.

[0047] In a fourth aspect, the present application further provides a communication device, which may be a second network element, a processor, a chip, a chip system, a circuit, or a functional module in the second network element. The communication device has the function of implementing the method in the first aspect or each possible design example of the first aspect. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions.

[0048] In one possible design, the structure of the communication device may include a processing unit and, optionally, a transceiver unit. These units may perform the functions of the method in the above-mentioned first aspect or various possible design examples of the first aspect, which are not elaborated here.

[0049] In one possible design, the communication device includes one or more processors and, optionally, a memory and / or a transceiver. The transceiver is used to transmit and receive data, messages, or information, and to communicate and interact with other devices in the system. The processor is configured to support the communication device in performing the corresponding functions described in the first aspect or various possible design examples of the first aspect. The memory is coupled to the processor and stores program instructions and data necessary for the communication device.

[0050] In a fifth aspect, the present application further provides a communication device, which may be a first network element, a processor, a chip, a chip system, a circuit, or a functional module in the first network element. The communication device has the function of implementing the method in the second aspect or each possible design example of the second aspect. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions.

[0051] In one possible design, the structure of the communication device may include a processing unit and, optionally, a transceiver unit. These units may perform the functions of the method in the above-mentioned second aspect or various possible design examples of the second aspect, which are not elaborated here.

[0052] In one possible design, the communication device includes one or more processors and, optionally, a memory and / or a transceiver. The transceiver is used to transmit and receive data, messages, or information, and to communicate and interact with other devices in the system. The processor is configured to support the communication device in performing the corresponding functions described in the second aspect or various possible design examples of the second aspect. The memory is coupled to the processor and stores program instructions and data necessary for the communication device.

[0053] In a sixth aspect, the present application further provides a communications device, which may be a proxy call session control function network element, a processor, a chip, a chip system, a circuit, or a functional module in the proxy call session control function network element. The communications device has the function of implementing the method described in the third aspect or various possible design examples of the third aspect. The functions may be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

[0054] In one possible design, the structure of the communication device may include a processing unit and, optionally, a transceiver unit. These units may perform the functions of the methods in the above-mentioned third aspect or various possible design examples of the third aspect, which are not elaborated here.

[0055] In one possible design, the communication device includes one or more processors and, optionally, a memory and / or a transceiver. The transceiver is used to transmit and receive data, messages, or information, and to communicate and interact with other devices in the system. The processor is configured to support the communication device in performing the corresponding functions described in the third aspect or various possible design examples of the third aspect. The memory is coupled to the processor and stores program instructions and data necessary for the communication device.

[0056] In a seventh aspect, an embodiment of the present application provides a communications system, which may include a first network element and a second network element. The second network element may be used to implement the method of the first aspect or each possible design example of the first aspect. The first network element may be used to implement the method of the second aspect or each possible design example of the second aspect.

[0057] In an eighth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores program instructions. When the program instructions are run on a computer, the computer executes the method described in the first aspect of the embodiment of the present application and any possible design thereof, or the second aspect and any possible design thereof, or the third aspect and any possible design thereof. Exemplarily, the computer-readable storage medium can be any available medium that can be accessed by a computer. Taking this as an example but not limited to: the computer-readable medium can include non-transitory computer-readable media, random-access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), CD-ROM or other optical disk storage, magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer.

[0058] In the ninth aspect, an embodiment of the present application provides a computer program product, including a computer program or instructions. When the computer program or instructions are run on a computer, the method described in the above-mentioned first aspect or any possible design of the first aspect, or the above-mentioned second aspect or any possible design of the second aspect, or the above-mentioned third aspect or any possible design of the third aspect is executed.

[0059] In the tenth aspect, the present application also provides a chip or chip system, comprising one or more processors, which are coupled to at least one memory and are used to read and execute program instructions stored in the memory, so that the chip or chip system implements the method described in the above-mentioned first aspect or any possible design of the first aspect, or the above-mentioned second aspect or any possible design of the second aspect, or the above-mentioned third aspect or any possible design of the third aspect.

[0060] For each of the above-mentioned aspects 4 to 10 and the technical effects that may be achieved by each of the aspects, please refer to the above-mentioned description of the technical effects that can be achieved by the first aspect or the various possible solutions in the first aspect, or the above-mentioned second aspect or the various possible solutions in the second aspect, or the above-mentioned third aspect or the various possible solutions in the third aspect, and no further details will be given here. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIG1 is a schematic diagram of the architecture of a communication system;

[0062] FIG2 is a flow chart of a communication method provided by the present application;

[0063] FIG3 is a flow chart of an example of a communication method provided by the present application;

[0064] FIG4 is a flow chart of an example of another communication method provided by the present application;

[0065] FIG5 is a flowchart of an example of another communication method provided by the present application;

[0066] FIG6 is a flowchart of an example of another communication method provided by the present application;

[0067] FIG7 is a schematic structural diagram of a communication device provided by the present application;

[0068] FIG8 is a structural diagram of a communication device provided in this application. DETAILED DESCRIPTION

[0069] The present invention provides a communication method and apparatus for optimizing satellite-based communication between terminal devices. The method and apparatus described herein are based on the same technical concept. Since the method and apparatus solve similar problems, the implementation of the apparatus and method can refer to each other, and any repetitions will not be repeated.

[0070] In the description of this application, words such as "first" and "second" are only used for the purpose of distinguishing the description and cannot be understood as indicating or implying relative importance or order.

[0071] In the description of this application, "at least one" means one or more, and "more" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c can be single or plural.

[0072] In the description of this application, "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. " / " means "or", for example, a / b means a or b.

[0073] In order to more clearly describe the technical solutions of the embodiments of the present application, the communication method and device provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0074] The technical solutions in the embodiments of the present application can be applied to various communication systems, such as universal mobile telecommunications system (UMTS), fourth generation (4G) mobile communication system (such as long term evolution (LTE) system), fifth generation (5G) mobile communication system (such as new radio (NR) system), and future evolved communication systems (such as sixth generation (6G) mobile communication system).

[0075] For example, Figure 1 shows a schematic diagram of the architecture of a possible communication system applicable to embodiments of the present application. As shown in Figure 1, the communication system may include at least two terminal devices, at least one satellite (STA) (Figure 1 uses three satellites STA1, STA2, and STA3 as an example), a gateway, an evaluation network element, a 5G core network (5GC), and a multimedia subsystem (intelligent manufacturing system, IMS).

[0076] Among them, terminal devices, which can also be referred to as user equipment (UE), mobile stations (MS), mobile terminals (MT), etc., are devices that provide voice and / or data connectivity to users. In Figure 1, two terminal devices, UE1 and UE2, are used as an example. For example, terminal devices can include handheld devices with wireless connection capabilities, vehicle-mounted devices, etc. Currently, terminal devices can be: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, XR devices, MR devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, etc.

[0077] The terminal device may also be a device-to-device communication (D2D) terminal device, a vehicle-to-everything (V2X) communication terminal device, an intelligent vehicle, a vehicle-to-machine system (or a telematics box, TBOX), a machine-to-machine / machine-type communication (M2M / MTC) terminal device, or an Internet of Things (IoT) terminal device. For example, the terminal device may be a vehicle, ship, or aircraft, or a terminal-type roadside unit, or a communication module or chip built into a vehicle or roadside unit. For example, the terminal device may be a vehicle-mounted module. The terminal device may also be a roadside unit (RSU).

[0078] In this application, the terminal device may also be a functional module, a chip or a chip system. Optionally, the functional module, the chip or the chip system may be provided in the terminal device.

[0079] A gateway, also known as a satellite gateway (also called a transmitter or hub), is a ground station that transmits data from a satellite to a local area network. A gateway can house antennas and equipment that convert radio frequency (RF) signals into Internet protocol (IP) signals for terrestrial connectivity.

[0080] The evaluation network element can also be called the on-board communication evaluation network element, the UE-SAT-UE function evaluation network element, or the UE-SAT-UE function confirmation network element. In short, this network element can determine whether satellite transmission is used for communication between terminal devices, and send the judgment result to the network element in the 5GC or IMS network.

[0081] 5GC can include multiple core network elements. For example, as shown in Figure 1, 5GC can include access and mobility management function (AMF) network element, session management function (SMF) network element, policy control function (PCF) network element, unified data management function (UDM) network element, etc. It should be understood that the core network elements shown in Figure 1 are only examples, and 5GC can also include other core network elements, which are not listed here one by one.

[0082] The AMF is primarily used for mobility and access management. For example, the AMF can perform mobility management, access authentication, or authorization. Furthermore, the AMF is responsible for delivering user policies between terminal devices and PCF network elements.

[0083] SMF is used to implement session management, including providing session management for UE sessions (such as session establishment, modification, and release), execution of control policies issued by PCF, selection and control of UPF, and UE IP address allocation.

[0084] PCF is responsible for policy control functions, including billing at the session and service flow levels, QoS bandwidth guarantee, mobility policy management, terminal device access policy, and other policy control functions.

[0085] UDM is responsible for unified data management functions, including user contract management, access authorization, and authentication information generation.

[0086] It should be understood that Figure 1 only illustrates the 5G core network. In future communications, core network elements may also have other names, and this application does not limit this.

[0087] The IMS can include network elements such as the proxy-call session control function (P-CSCF), the interrogating-CSCF (I-CSCF), and the serving-CSCF (S-CSCF). The P-CSCF is the user's first point of contact in their home or visited network. The I-CSCF is the user's first entry point into their home network and is responsible for assigning an S-CSCF, performing routing queries, and hiding inter-domain topology. The S-CSCF is the core of the IMS, responsible for terminal device registration and authentication, session control, and service triggering.

[0088] In some embodiments, access network equipment and user plane function (UPF) network elements may be deployed on a satellite, or access network equipment, UPF, and access gateway (AGW) may be deployed on a satellite. When the access network equipment and UPF are deployed on a satellite, there may be no communication connection between the evaluation network element and the IMS (i.e., the dotted line between the evaluation network element and the IMS in FIG1 does not exist). When the access network equipment, UPF, and AGW are deployed on a satellite, there may or may not be a communication connection between the evaluation network element and the IMS (i.e., the dotted line between the evaluation network element and the IMS in FIG1 may or may not exist).

[0089] Access network equipment is a device used to provide access for terminal devices. Access network equipment may include radio access network (RAN) equipment, such as base stations. Access network equipment may be a base station, an evolved Node B in a long term evolution (LTE) system or long term evolution-advanced (LTE-A), which may be referred to as eNB or e-NodeB for short), a transmission reception point (TRP), a next generation NodeB (gNB) in a fifth generation (5G) mobile communication system, a next generation base station in a sixth generation (6G) mobile communication system, a base station in a future mobile communication system, or an access node in a wireless local area network (WiFi) system, etc. It may also be an access network device in an open access network (ORAN) system, etc. Optionally, the access network device may also be a module or unit that performs some of the functions of the base station. For example, the access network device may be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU here performs the functions of the radio resource control protocol and the packet data convergence protocol (PDCP) of the base station, and may also perform the functions of the service data adaptation protocol (SDAP); the DU performs the functions of the radio link control layer and the medium access control (MAC) layer of the base station, and may also perform the functions of part of the physical layer or all of the physical layer. In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU can also be called O-CU, DU can also be called open (open, O)-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CUP-UP, and RU can also be called O-RU.

[0090] Exemplarily, the access network device can be a macro base station, a micro base station (also known as a small station) or an indoor station, or a relay node or a donor node, etc. The access network device can also be a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (for example, a home evolved NodeB, or a home Node B, HNB), a base band unit (BBU) or a remote radio unit (RRU), or a wireless fidelity (Wifi) access point (AP), or a baseband pool (BBU pool) and RRU in a cloud radio access network (CRAN), etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the access network device.

[0091] In this application, the access network device may also be a functional module, a chip or a chip system. Optionally, the functional module, the chip or the chip system may be provided in the access network device.

[0092] The UPF is responsible for the user plane functions of the core network, including forwarding and processing user messages, connection to the data network (DN), session anchoring, and quality of service (QoS) policy enforcement.

[0093] The AGW is the access gateway of the IMS, also called the IMS-AGW. It can accept the control of the P-CSCF to implement gateway control of media flows, local network address translation (NAT), IP domain indication, remote NAT traversal, message filtering, traffic policy, QoS marking, etc., to ensure the normal operation and security of the IMS network.

[0094] It should be understood that the communication system shown in Figure 1 is not limited to including only the network elements shown in the figure, but may also include other devices not shown in the figure, which are not listed here. In addition, the layout of the devices or network elements shown in Figure 1 is only exemplary and is not limited in this application.

[0095] For ease of explanation, in this application, the XX network element may be referred to as XX. For example, the SMF network element may be referred to as SMF. It should be understood that all network element names in this application are merely examples and may be referred to by other names in future communications. Alternatively, the network elements involved in this application may be replaced by other entities or devices with the same functions in future communications. This application does not limit this. This is a unified description here and will not be repeated later.

[0096] As satellites move, the access situation of terminal devices to satellites is uncontrollable. There is no guarantee that terminal devices can always be covered by the same satellite, or that there is an inter-satellite link or inter-satellite route between any two satellites at any time. These situations may affect whether satellite transmission is used for communication between terminal devices. Therefore, whether satellite transmission is used for communication between terminal devices in various scenarios needs to be accurately determined. Based on this, an embodiment of the present application provides a communication method to optimize the use of satellite transmission for communication between terminal devices, so that a more appropriate communication method can be determined in various scenarios.

[0097] In the embodiments of the present application, the operation performed by a certain device or network element may be performed by the device or network element, or by a processor, chip, chip system, circuit, or functional module in the device or network element. In the following description of the embodiments, only the execution of a certain device or network element is used as an example.

[0098] In the embodiment of the present application, a certain device or network element sends information to another device or network element, which may be sent directly or indirectly through one or more other devices, and the present application does not limit this.

[0099] Based on the above description, an embodiment of the present application provides a communication method, as shown in FIG2 . The process of the method may include:

[0100] Step 201: A first network element sends a first request to a second network element.

[0101] The first request may be used to request whether to communicate between the first terminal device and the second terminal device using satellite transmission. Specifically, the first request may be a service request message transmitted via an interface between the first network element and the second network element, or the first request may be included in a service request message transmitted via an interface between the first network element and the second network element.

[0102] Optionally, the interface between the first network element and the second network element includes but is not limited to a service-oriented interface, a hypertext transfer protocol (HTTP) interface, an N4 interface, an IP interface, etc.

[0103] Correspondingly, the second network element receives the first request from the first network element.

[0104] The first network element may be a session management function network element, a policy control function network element, or a proxy call session control function network element. The second network element may be the evaluation network element described above.

[0105] A first terminal device accesses a first satellite, and a second terminal device accesses a second satellite. The first satellite and the second satellite may be the same satellite, in which case the first terminal device and the second terminal device access the same satellite. Alternatively, the first satellite and the second satellite may be different satellites, in which case the first terminal device and the second terminal device access different satellites.

[0106] In the present application, accessing the first satellite may also be described as accessing from the first satellite, being located at the first satellite, or being covered by the signal of the first satellite. The same applies to accessing the second satellite.

[0107] In the present application, whether the first terminal device and the second terminal device communicate using satellite transmission can be understood as whether the first terminal device and the second terminal device communicate using an inter-satellite link transmission method, or whether the first terminal device and the second terminal device use core network elements and / or IMS network elements on the satellite for transmission, or whether the first terminal device and the second terminal device communicate using a UE-SAT-UE method, or whether the first terminal device and the second terminal device enable the UE-STA-UE function, without limitation.

[0108] In this application, satellite transmission communication may also be referred to as UE-SAT-UE communication or on-satellite communication. Specifically, satellite transmission communication may refer to the local exchange or forwarding of service data between two terminal devices via the same satellite, or the inter-satellite exchange or forwarding between multiple satellites, without the need for ground network element exchange or forwarding via the feeder link between the satellite access network equipment and the ground gateway.

[0109] It can also be understood that satellite transmission communication can be local exchange on the satellite, or it can be direct exchange between network elements between satellites (between user plane functional network elements on the satellite and / or between access gateways on the satellite), without the need to communicate through the gateway station and the ground path. It can also be understood that communication does not need to be carried out through the ground network element after the feeder link is landed.

[0110] In an optional embodiment, the first request may include identification information of the first satellite, identification information of the second satellite, information of the first terminal device, and information of the second terminal device. It should be understood that the identification information of the first satellite may also be described as identification information of the first satellite, and the identification information of the second satellite may also be described as identification information of the second satellite, etc.

[0111] Optionally, the first request may further include demand information or demand indication information for communication between the first terminal device and the second terminal device using satellite transmission, wherein the demand information or demand indication information for communication using satellite transmission may also be referred to as UE-SAT-UE service indication.

[0112] In scenario a1, access network equipment and user plane function network elements can be deployed on the satellite. In scenario a2, access network equipment, user plane function network elements, and an access gateway can be deployed on the satellite. The information in the first request or the operations of the first and second network elements may vary in different scenarios. The following describes each scenario separately.

[0113] In scenario a1, the identification information of the first satellite can be the identifier of the first satellite, the identifier of the first user plane function network element, the identifier of the first access network device, the identifier of the first sector (which can also be understood as the identifier of the first cell), or the identifier of the first beam deployed on the first satellite. The first user plane function network element and the first access network device are located on the first satellite; the first sector (or the first cell) is the cell corresponding to the first access network device on the first satellite. The first beam identified by the identifier of the first beam is deployed on the first satellite. Therefore, based on the first beam identified by the identifier of the first beam, it can be determined that the first satellite covers the first terminal device, and the first beam can be used for the first terminal device to access the network.

[0114] Optionally, when the first network element stores a mapping relationship between the identifier of the first user plane function network element and the identifier of the first access network device, the identification information of the first satellite may be the identifier of the first user plane function network element. When the first network element does not store a mapping relationship between the identifier of the first user plane function network element and the identifier of the first access network device, the identification information of the first satellite may be the identifier of the first access network device. In this case, the second network element may store a mapping relationship between the identifier of the first access network device, the identifier of the first user plane function network element, and the identifier of the first satellite.

[0115] The identification information of the second satellite may be an identifier of the second satellite, an identifier of a second user plane function network element, an identifier of a second access network device, an identifier of a second satellite, an identifier of a second sector (which may also be understood as an identifier of a second cell), or an identifier of a second beam deployed on the second satellite, wherein the second user plane function network element and the second access network device are located on the second satellite; the second sector (or second cell) is the cell corresponding to the second access network device on the second satellite. Since the second beam identified by the identifier of the second beam is deployed on the second satellite, the second beam identified based on the identifier of the second beam may indicate that the second satellite covers the second terminal device, and the second beam may be used for the second terminal device to access the network.

[0116] Optionally, when the first network element stores a mapping relationship between the identifier of the second user plane function network element and the identifier of the second access network device, the identification information of the second satellite may be the identifier of the second user plane function network element. When the first network element does not store a mapping relationship between the identifier of the second user plane function network element and the identifier of the second access network device, the identification information of the second satellite may be the identifier of the second access network device. In this case, the second network element may store a mapping relationship between the identifier of the second access network device, the identifier of the second user plane function network element, and the identifier of the second satellite.

[0117] In scenario a2, the identification information of the first satellite and the identification information of the second satellite may be the same as in scenario a1. Alternatively, in scenario a2, the identification information of the first satellite may be the identifier of the first access gateway, and the identification information of the second satellite may be the identifier of the second access gateway. The first access gateway is located on the first satellite, and the second access gateway is located on the second satellite.

[0118] Optionally, in scenario a2, the identification information of the first satellite may also be the identification information of the first satellite in scenario a1 and the identifier of the first access gateway. For example, in scenario a2, the identification information of the first satellite may be the identifier of the first satellite, the identifier of the first user plane function network element, the identifier of the first sector (which may also be understood as the identifier of the first cell), or the identifier of the first beam deployed on the first satellite, and the identifier of the first access gateway. Similarly, the identification information of the second satellite may also be the identification information of the second satellite in scenario a1 and the identifier of the second access gateway. For example, in scenario a2, the identification information of the second satellite may be the identifier of the second satellite, the identifier of the second user plane function network element, the identifier of the second sector (which may also be understood as the identifier of the second cell), or the identifier of the second beam deployed on the second satellite, and the identifier of the second access gateway. This application does not limit this.

[0119] In scenario a1, the information of the first terminal device may include one or more of the following: the identification of the first terminal device, the IP address of the first terminal device, the location information of the first terminal device, the movement trajectory of the first terminal device, or the identification information of the first satellite; the information of the second terminal device includes one or more of the following: the identification of the second terminal device, the IP address of the second terminal device, the location information of the second terminal device, the movement trajectory of the second terminal device, or the identification information of the second satellite.

[0120] In scenario a2, the information of the first terminal device and the second terminal device can be the same as in scenario a1. Optionally, when the information of the first terminal device is the identification information of the first satellite, in scenario a2, the identification information of the first satellite can be represented by the identifier of the first access gateway. Similarly, when the information of the second terminal device is the identification information of the second satellite, in scenario a2, the identification information of the second satellite can be represented by the identifier of the second access gateway.

[0121] In some embodiments, before the first network element sends a first request to the second network element, the first terminal device and the second terminal device may, in a registration process or in a protocol data unit (PDU) session establishment process or in a service request process, respectively send their respective location information or movement trajectories to the access and mobility management function network element based on their respective device capabilities or subscription information. Further, the access and mobility management function network element may send the location information or movement trajectory of the first terminal device or information of the first satellite, and the location information or movement trajectory or information of the second satellite of the second terminal device to the session management function network element.

[0122] Optionally, the information about the first satellite sent by the access and mobility management function network element to the session management network element may be an identifier of the first access network device, an identifier of the first user plane function network element, or an identifier of the first satellite. When the access and mobility management function network element stores a mapping relationship between the identifier of the first access network device and the identifier of the first satellite, the information about the first satellite may be the identifier of the first satellite.

[0123] Similarly, the information about the second satellite sent by the access and mobility management function network element to the session management network element may be an identifier of the second access network device, an identifier of the second user plane function network element, or an identifier of the second satellite. Specifically, when the access and mobility management function network element stores a mapping relationship between the identifier of the second access network device and the identifier of the second satellite, the information about the second satellite may be the identifier of the second satellite.

[0124] Afterwards, the first terminal device or the second terminal device may initiate a voice call process (eg, an Invite process). Optionally, in this process, the terminal device initiating the voice call process may send a UE-SAT-UE service indication to the proxy call session control function network element.

[0125] Furthermore, the proxy call session control function network element may initiate a voice quality of service flow (QoS flow) establishment process. In this process, the proxy call session control function network element may send information about the first terminal device and information about the second terminal device to the policy control function network element. Optionally, the proxy call session control function network element may also send a UE-SAT-UE service indication to the policy control function network element. The UE-SAT-UE service indication may be received by the proxy call session control function network element from the terminal device that initiates the voice call process, or may be obtained by the proxy call session control function network element from the subscription data of the UDM, or may be obtained based on the stored terminal device identifier and the configuration information of the UE-SAT-UE service indication.

[0126] Optionally, in scenario a2, during the QoS flow establishment process, the proxy call session control function network element may further send, to the policy control function network element, indication information indicating that the access gateway is deployed on a satellite. The proxy call session control function network element may further send, to the policy control function network element, an identifier of the first access gateway and an identifier of the second access gateway.

[0127] When the first network element is a proxy call session control function network element, the proxy call session control function network element may send the first request to the second network element. It should be understood that the order in which the proxy call session control function network element initiates the QoS flow establishment process and sends the first request to the second network element is not limited in this application.

[0128] The policy control function network element may send information about the first terminal device and information about the second terminal device to the session management function network element. Optionally, the policy control function network element may send a UE-SAT-UE service indication to the session management function network element. For example, the policy control function network element may send the above information to the session management function network element through the SMF policy association revision process.

[0129] Optionally, in scenario a2, the policy control function network element may further send indication information indicating that the access gateway is deployed on a satellite to the session management function network element. The policy control function network element may further send an identifier of the first access gateway and an identifier of the second access gateway to the session management function network element.

[0130] When the first network element is a policy control function network element, the policy control function network element may send the first request to the second network element. It should be understood that the order in which the policy control function network element sends the above information to the session management function network element and sends the first request to the second network element is not limited in this application.

[0131] When the first network element is a session management function network element, the session management function network element sends the first request to the second network element after receiving the above information from the policy control function network element.

[0132] Step 202: The second network element sends first indication information to the first network element based on the first request. The first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, or the first indication information is used to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission. Accordingly, the first network element receives the first indication information from the second network element.

[0133] In an optional implementation, the second network element sends the first indication information to the first network element according to the first request. The method may be: the second network element determines the first indication information according to the first request and the first principle, and sends the first indication information to the first network element.

[0134] Among them, the second network element stores at least one of the following information: topological information of nodes and links between the satellite and the ground and between satellites, ephemeris information, load information on nodes or links, etc. The second network element can determine whether the first terminal device and the second terminal device communicate using satellite transmission based on the information in the first request and the stored information and the first principle, that is, determine the first indication information.

[0135] Optionally, the load information on the node or link may be sent by the network elements on the ground and the satellite to the session management function network element or the proxy call session control function network element, and then sent by the session management function network element or the proxy call session control function network element to the second network element for storage.

[0136] It should be understood that when the load of a node or link exceeds a load threshold, the corresponding node or load should be bypassed.

[0137] For example, the first principle may include one or more of the following:

[0138] If the delay of communication between the first terminal device and the second terminal device using satellite transmission is less than the delay of communication between the first terminal device and the second terminal device using terrestrial transmission, the first terminal device and the second terminal device communicate with each other using satellite transmission; or

[0139] If the number of nodes in a path between the first terminal device and the second terminal device using satellite transmission is less than the number of nodes in a path between the first terminal device and the second terminal device using terrestrial transmission, the first terminal device and the second terminal device communicate with each other using satellite transmission; or

[0140] If the time delay for communication between the first terminal device and the second terminal device using satellite transmission is less than the time delay for communication between the first terminal device and the second terminal device using terrestrial transmission, and the movement directions of the first satellite and the second satellite are consistent, and the time delay for communication between the first terminal device and the second terminal device using satellite transmission is greater than or equal to the first time delay, then the first terminal device and the second terminal device communicate with each other using satellite transmission; or

[0141] The number of path nodes for communication between the first terminal device and the second terminal device using satellite transmission is less than the number of path nodes for communication between the first terminal device and the second terminal device using ground transmission, and the movement directions of the first satellite and the second satellite are consistent, and the number of path nodes for communication between the first terminal device and the second terminal device using satellite transmission is less than or equal to the first node number threshold, then the first terminal device and the second terminal device communicate using satellite transmission.

[0142] In some embodiments, when the first network element is a session management function network element, after the session management function network element receives the first indication information, when the first indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method, the session management function network element may send a second indication information to the proxy call session control function network element through the policy control function network element, and the second indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method.

[0143] Optionally, in some scenarios, the session management function network element and the proxy call session control function network element may communicate directly, and the session management function network element may directly send the second indication information to the proxy call session control function network element.

[0144] In the aforementioned scenario a1, after the proxy call session control function network element receives the second indication information, if there are subsequent requests such as data detection or traffic billing, the proxy call session control function network element negotiates with the 5GC regarding data detection or traffic billing.

[0145] Exemplarily, the negotiation between the proxy call session control function network element and the 5GC may include the following content: Since the access gateway is bypassed by the IMS network element during the voice media stream transmission in scenario a1, when there is a demand for data detection or traffic billing statistics, the proxy call session control function network element notifies the received data detection or traffic billing statistics information to the policy control function network element of the 5GC, which is then sent to the session management function network element. The session management function network element executes the corresponding data detection or traffic billing statistics business process to notify the corresponding user plane function network element to perform corresponding data detection or traffic billing.

[0146] This can also be understood as the proxy call session control function network element negotiating with the 5GC on which network element to initiate data detection or traffic billing functions. For example, in scenario a1, since there is no access gateway deployed on the satellite, data detection or traffic billing functions need to be executed on the user plane function network element. The request information for data detection or traffic billing functions is sent to the IMS network domain. Therefore, the IMS network domain needs to notify the 5GC to implement data detection or traffic billing functions in the 5GC domain.

[0147] In the aforementioned scenario a2, after the proxy call session control function network element receives the second indication information, if the loads of the first access gateway and the second access gateway are both less than or equal to the first load threshold, the proxy call session control function network element determines, based on the second indication information, that the first target access gateway is the first access gateway and the second target access gateway is the second access gateway, and sends the identifier of the first target access gateway and the identifier of the second target access gateway to the session management function network element.

[0148] In some embodiments, when the first network element is a session management function network element, after the session management function network element receives the first indication information, when the first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, the first network element sends the flow rules of the first terminal device and the second terminal device to the first user plane function network element and the second user plane function network element; the first user plane function network element is located on the first satellite, and the second user plane function network element is located on the second satellite; and / or, when the first indication information is used to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission, the first network element sends the flow rules of the first terminal device and the second terminal device to the user plane function network element located on the ground. It can also be understood that when the first indication information is used to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission, the data transmission between the first terminal device and the second terminal device is not transmitted via the satellite, but is transmitted via the network element on the ground.

[0149] Optionally, the first network element sends the flow rules of the first terminal device and the second terminal device to the user plane function network element located on the ground. The first network element may send the flow rules of the first terminal device and the second terminal device to the proxy call session control function network element. Further, the proxy call session control function network element selects a ground access gateway and sends the flow rules of the first terminal device and the second terminal device to the selected ground access gateway.

[0150] Flow rules can also be described as user service flow rules or service message rules. Flow rules can include one or more of the following: uplink or downlink message detection rules, message matching rules, QoS enforcement rules, traffic diversion rules, usage reporting rules, forwarding action rules, etc.

[0151] In one example, when the first network element is a session management function network element, in the aforementioned scenario a1, when the first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, the first network element can also establish a tunnel between the first satellite and the second satellite.

[0152] The tunnel between the first satellite and the second satellite may be understood as a tunnel between a first user plane function network element on the first satellite and a second user plane function network element on the second satellite.

[0153] Optionally, the first network element may also establish a tunnel between the first access network device and the first user plane function network element, and a tunnel between the second user plane function network element and the second access network.

[0154] In this example, the transmission path between the first terminal device and the second terminal device can be first terminal device-first access network device-first user plane function network element-second user plane function network element-second access network device-second terminal device.

[0155] It should be understood that if the first satellite and the second satellite are the same satellite, the first user plane function network element and the second user plane function network element can be the same user plane function network element. Optionally, the transmission path between the first terminal device and the second terminal device can be the first terminal device-first access network device-first user plane function network element (that is, the second user plane function network element)-second access network device-second terminal device.

[0156] It should be understood that the transmission path between the second terminal device and the first terminal device can be a reverse path of the aforementioned path, or a path in other order other than the reverse order, which is not limited in this application.

[0157] In another example, when the first network element is a session management function network element and the first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, in the aforementioned scenario a2, the first network element can send the flow rules between the first terminal device and the second terminal device to the first access gateway and the second access gateway.

[0158] Optionally, the first network element may send the flow rules between the first terminal device and the second terminal device to the first access gateway and the second access gateway. This may be the case where the first network element sends the flow rules between the first terminal device and the second terminal device to the first access gateway and the second access gateway via a proxy call session control function network element. For example, a specific method may be: the first network element sends traffic-related rule information between the first terminal device and the second terminal device to the proxy call session control function network element via a policy control function network element. Further, the proxy call session control function network element sends corresponding session description protocol (SDP) information and / or forwarded user plane function network element IP routing information to the first access gateway and the second gateway via IMS-related processes and signaling.

[0159] In this example, the transmission path between the first terminal device and the second terminal device can be the first terminal device-first access network device-first user plane function network element-first access gateway-second access gateway-second user plane function network element-second access network device-second terminal device.

[0160] It should be understood that if the first satellite and the second satellite are the same satellite, the first user plane function network element and the second user plane function network element can be the same user plane function network element, the first access gateway and the second access gateway can be the same access gateway. Optionally, the transmission path between the first terminal device and the second terminal device can be the first terminal device-first access network device-first user plane function network element (that is, the second user plane function network element)-first access gateway (that is, the second access gateway)-second access network device-second terminal device.

[0161] In an optional embodiment, the session management function network element may receive an identifier of the first access gateway and an identifier of the second access gateway from the proxy call session control function network element or from the policy control function network element; further, the first network element sends the flow rules between the first terminal device and the second terminal device to the first access gateway and the second access gateway, and the method may be: the first network element sends the flow rules between the first terminal device and the second terminal device to the first access gateway according to the identifier of the first access gateway; and the first network element sends the flow rules between the first terminal device and the second terminal device to the second access gateway according to the identifier of the second access gateway.

[0162] The session management function network element receives the identifier of the first access gateway and the identifier of the second access gateway from the proxy call session control function network element or the policy control function network element, which may be received through the QoS flow establishment process and SMF policy association revision process described above, or may be sent to the session management function network element after the proxy call session control function network element receives the second indication information from the session management function network element.

[0163] In an optional implementation, when the first network element is a proxy call session control function network element or a policy control function network element, after receiving the first indication information, the proxy call session control function network element or the policy control function network element sends the first indication information to the session management function network element.

[0164] Furthermore, after receiving the first indication information, the session management function network element can still perform the corresponding operations of the session management function network element described above according to the different indications of the first indication information. For example, when the first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, the first network element sends the flow rules of the first terminal device and the second terminal device to the first user plane function network element and the second user plane function network element, and other operations. Please refer to the above description and will not repeat them here.

[0165] In some embodiments, the second network element may further send information about a first transmission path to the first network element, where the first transmission path is used for communication between the first terminal device and the second terminal device using satellite transmission. Correspondingly, the first network element may receive information about the first transmission path from the second network element.

[0166] Exemplarily, when the second network element determines the first indication information, and the first indication information indicates that the first terminal device and the second terminal device communicate using satellite transmission, if the second network element determines that the paths based on the first satellite and the second satellite transmission are worse than the paths based on other satellite transmissions, the second network element can determine the first transmission path and send information about the first transmission path to the first network element.

[0167] In scenario a1, when the transmission delay between the first user plane function network element and the second user plane function network element is greater than the transmission delay between the third user plane function network element and the fourth user plane function network element, the second network element may determine the first transmission path; and / or when the number of path nodes between the first user plane function network element and the second user plane function network element is greater than the number of path nodes between the third user plane function network element and the fourth user plane function network element, the second network element may determine the first transmission path. The first user plane function network element is located on a first satellite, the second user plane function network element is located on a second satellite, the third user plane function network element is located on a third satellite, and the fourth user plane function network element is located on a fourth satellite.

[0168] The transmission delay between the first user plane function network element and the second user plane function network element is greater than the transmission delay between the third user plane function network element and the fourth user plane function network element. It can be understood that after the first terminal device and the second terminal device are respectively connected to the corresponding access network devices, the transmission delay through the first access network device, the first user plane function network element, the second user plane function network element and the second access network device is greater than the transmission delay between the first access network device, the third user plane function network element, the fourth user plane function network element and the second access network device.

[0169] Similarly, the number of path nodes between the first user plane functional network element and the second user plane functional network element is greater than the number of path nodes between the third user plane functional network element and the fourth user plane functional network element. It can be understood that after the first terminal device and the second terminal device are respectively connected to the corresponding access network devices, the number of path nodes between the first access network device, the first user plane functional network element, the second user plane functional network element and the second access network device through the first access network device, the first user plane functional network element, the second user plane functional network element and the second access network device is greater than the number of path nodes between the first access network device, the third user plane functional network element, the fourth user plane functional network element and the second access network device.

[0170] It should be understood that the transmission path described above is the path sequence for transmission from the first terminal device to the second terminal device. The path sequence for transmission from the second terminal device to the first terminal device can be reverse or can be information of other non-reverse transmission paths. This application does not limit this.

[0171] Accordingly, the information of the first transmission path may include an identifier of the third user plane function network element (or an identifier of the third satellite) and an identifier of the fourth user plane function network element (or an identifier of the fourth satellite).

[0172] Optionally, the information of the first transmission path may further include an identifier of the first access network device and an identifier of the second access network device.

[0173] In one example, the first network element is a session management function network element, and the information of the first transmission path includes an identifier of a third user plane function network element and an identifier of a fourth user plane function network element. When the first indication information is used to indicate that satellite transmission is used to communicate between the first terminal device and the second terminal device, the session management function network element can establish a tunnel between the third satellite and the fourth satellite based on the information of the first transmission path.

[0174] The tunnel between the third satellite and the fourth satellite may be understood as a tunnel between a third user plane function network element on the third satellite and a fourth user plane function network element on the fourth satellite.

[0175] Optionally, the session management function network element may also create a tunnel between the first access network device and the third satellite, and a tunnel between the fourth satellite and the second access network device.

[0176] Among them, the tunnel between the first access network device and the third satellite can be understood as the tunnel between the first access network device and the third user plane functional network element, and the tunnel between the fourth satellite and the second access network device can be understood as the tunnel between the fourth user plane functional network element and the second access network device.

[0177] In scenario a2, when the transmission delay between the first user plane function network element, the first access gateway, the second access gateway, and the second user plane function network element is greater than the transmission delay between the third user plane function network element, the third access gateway, the fourth access gateway, and the fourth user plane function network element, the second network element may determine the first transmission path; and / or when the number of path nodes between the first user plane function network element, the first access gateway, the second access gateway, and the second user plane function network element is greater than the number of path nodes between the third user plane function network element, the third access gateway, the fourth access gateway, and the fourth user plane function network element, the second network element may determine the first transmission path. The first user plane function network element and the first access gateway are located on a first satellite, the second user plane function network element and the second access gateway are located on a second satellite, the third user plane function network element and the third access gateway are located on a third satellite, and the fourth user plane function network element and the fourth access gateway are located on a fourth satellite.

[0178] Among them, this application only takes the example that the third user plane function network element and the third access gateway are located on the same satellite, and the fourth user plane function network element and the fourth access gateway are located on the same satellite. Optionally, the third user plane function network element and the third access gateway can be located on different satellites, and the fourth user plane function network element and the fourth access gateway can be located on different satellites. This application does not limit this.

[0179] The transmission delay between the first user plane function network element, the first access gateway, the second access gateway and the second user plane function network element is greater than the transmission delay between the third user plane function network element, the third access gateway, the fourth access gateway and the fourth user plane function network element. It can be understood that after the first terminal device and the second terminal device respectively access the corresponding access network devices, the transmission delay between the first access network device, the first user plane function network element, the first access gateway, the second access gateway, the second user plane function network element and the second access network device through the first access network device, the first user plane function network element, the first access gateway, the second access gateway, the second user plane function network element and the second access network device is greater than the transmission delay between the first access network device, the third user plane function network element, the third access gateway, the fourth access gateway, the fourth user plane function network element and the second access network device.

[0180] Similarly, the number of path nodes between the first user plane functional network element and the second user plane functional network element is greater than the number of path nodes between the third user plane functional network element and the fourth user plane functional network element. It can be understood that after the first terminal device and the second terminal device are respectively connected to the corresponding access network devices, the number of path nodes between the first access network device, the first user plane functional network element, the first access gateway, the second access gateway, the second user plane functional network element and the second access network device is greater than the number of path nodes between the first access network device, the third user plane functional network element, the third access gateway, the fourth access gateway, the fourth user plane functional network element and the second access network device.

[0181] It should be understood that the transmission path described above is the path sequence for transmission from the first terminal device to the second terminal device. The path sequence for transmission from the second terminal device to the first terminal device can be reverse, or it can be information on other non-reverse transmission paths, such as the second access network device, the second user plane function network element, the second access gateway, the third access gateway, the third user plane function, the first access network device, etc. This application does not limit this.

[0182] Accordingly, the information of the first transmission path may include the identifier of the third user plane function network element (or the identifier of the third satellite) and the identifier of the fourth user plane function network element (or the identifier of the fourth satellite) as well as the identifier of the third access gateway and the identifier of the fourth access gateway.

[0183] Optionally, the information of the first transmission path may further include an identifier of the first access network device and an identifier of the second access network device.

[0184] Optionally, the information of the first transmission path may include the aforementioned information in the order of the network elements of the transmission path. For example, if the transmission is from the first terminal device to the second terminal device, the information of the first transmission path may include the identifier of the third user plane function network element, the identifier of the third access gateway, the identifier of the fourth access gateway, and the identifier of the fourth user plane function network element. If the transmission is from the second terminal device to the first terminal device, the information of the first transmission path may include the identifier of the fourth user plane function network element, the identifier of the fourth access gateway, the identifier of the third access gateway, and the identifier of the third user plane function network element.

[0185] It should be understood that the order of the identifiers included in the information of the aforementioned first transmission path is only an example, and there may be other orders, which is not limited in this application.

[0186] In one possible manner, when the first network element is a session management function network element, and the information of the first transmission path includes an identifier of a third user plane function network element, an identifier of a fourth user plane function network element, and an identifier of a third access gateway, and an identifier of a fourth access gateway, when the first indication information is used to indicate that communication between the first terminal device and the second terminal device adopts a satellite transmission mode, the session management function network element may request the proxy call session control function network element to adopt the first transmission path based on the information of the first transmission path; and further, the session management function network element determines whether to adopt the first transmission path based on a response of the proxy call session control function network element to the request.

[0187] Optionally, the session management function network element requests the proxy call session control function network element to adopt the first transmission path based on the information of the first transmission path. This can be achieved by the following method: the session management function network element sends the identifier of the third access gateway and the identifier of the fourth access gateway to the proxy call session control function network element.

[0188] The session management function network element determines whether to adopt the first transmission path based on the proxy call session control function network element's response to the request. This can be achieved by: if the session management function network element receives an identifier of the third access gateway and an identifier of the fourth access gateway from the proxy call session control function network element, the session management function network element determines to adopt the first transmission path; and / or if the session management function network element receives an identifier of an access gateway other than the identifier of the third access gateway and the identifier of the fourth access gateway from the proxy call session control function network element, the session management function network element determines not to adopt the first transmission path.

[0189] Accordingly, after the proxy call session control function network element receives the identifier of the third access gateway and the identifier of the fourth access gateway from the session management function network element, if the load of the third access gateway and the fourth access gateway are both less than or equal to the first load threshold, the proxy call session control function network element sends the identifier of the third access gateway and the identifier of the fourth access gateway to the session management function network element. If the load of at least one of the third access gateway and the fourth access gateway is greater than the first load threshold, the proxy call session control function network element sends the identifiers of access gateways other than the identifier of the third access gateway and the identifier of the fourth access gateway to the session management function network element.

[0190] When the session management function network element determines not to use the first transmission path, the session management function network element may send a second request to the second network element, the second request being used to request whether satellite transmission should be used for communication between the first terminal device and the second terminal device. Furthermore, the session management function network element receives third indication information from the second network element, the third indication information being used to indicate whether satellite transmission should be used for communication between the first terminal device and the second terminal device, or the third indication information being used to indicate whether satellite transmission should not be used for communication between the first terminal device and the second terminal device. In other words, when the session management function network element determines not to use the first transmission path, it may again request the second network element whether satellite transmission should be used for communication between the first terminal device and the second terminal device.

[0191] Optionally, the second request message may include identifiers of access gateways sent by the proxy call session control function network element to the session management function network element except for the identifier of the third access gateway and the identifier of the fourth access gateway.

[0192] In another possible manner, the first network element is a proxy call session control function network element, and the information of the first transmission path includes an identifier of a third user plane function network element, an identifier of a fourth user plane function network element, and an identifier of a third access gateway and an identifier of a fourth access gateway. When the first indication information is used to indicate that satellite transmission is used for communication between the first terminal device and the second terminal device, if loads of the third access gateway and the fourth access gateway are both less than or equal to a first load threshold, the proxy call session control function network element may send the identifier of the third access gateway, the identifier of the fourth access gateway, and the first indication information to the session management function network element. Alternatively, if the load of at least one of the third access gateway and the fourth access gateway is greater than the first load threshold, the proxy call session control function network element may send a third request to the second network element, where the third request is used to request whether satellite transmission is used for communication between the first terminal device and the second terminal device.

[0193] Optionally, the proxy call session control function network element may also send the first load threshold to a second network element. The second network element may use the first load threshold to determine the load status of the access gateway, and then determine a transmission path that ultimately meets the load requirements. For example, the first transmission path determined by the second network element may be the transmission path that can ultimately be adopted.

[0194] In some embodiments, as the satellite moves, the first terminal device and / or the second terminal device may undergo satellite switching. When the first terminal device and / or the second terminal device undergoes satellite switching, the first network element may send a fourth request to the second network element, the fourth request being used to request whether the first terminal device and the second terminal device communicate using satellite transmission; the first network element may receive fourth indication information from the second network element, the fourth indication information being used to indicate whether the first terminal device and the second terminal device communicate using satellite transmission, or to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission. That is, when the first terminal device and / or the second terminal device undergoes satellite switching, the first network element may again request the second network element whether the first terminal device and the second terminal device communicate using satellite transmission.

[0195] Optionally, in the aforementioned scenario a1, when the first network element is a session management function network element, when the fourth indication information is used to indicate that communication between the first terminal device and the second terminal device is not to be conducted via satellite transmission, the first network element deletes the tunnel between the first satellite and the second satellite. That is, the first network element deletes the tunnel between the first user plane function network element on the first satellite and the second user plane function network element on the second satellite. This deletion, also called release, is achieved through a session modification procedure, a session update procedure, or a session release procedure between the first network element and the inter-satellite network element.

[0196] Optionally, the first network element may further delete the tunnel between the first access network device and the first user plane function network element, delete the tunnel between the second user plane function network element and the second access network device, and delete the flow rule between the first terminal device and the second terminal device. The deletion, which may also be called release, is implemented through a session modification process, a session update process, or a session release process between the first network element and the inter-satellite network element.

[0197] Optionally, in the aforementioned scenario a2, when the first network element is a session management function network element, when the fourth indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, and an access gateway is deployed on the target satellite of the terminal device where satellite switching occurs, the session management function network element can send a switching indication to the proxy call session control function network element, and the switching indication is used to indicate the path switching between the first terminal device and the second terminal device.

[0198] Furthermore, the proxy call session control function network element may send first information to the first terminal device or the second terminal device according to the switching indication, where the first information is used to initiate a voice call process.

[0199] Based on the above communication method, the second network element can evaluate whether the first terminal device and the second terminal device communicate using satellite transmission, so that the more appropriate communication method between the first terminal device and the second terminal device can be accurately determined in each scenario, thereby improving communication efficiency.

[0200] Based on the above embodiments, the communication method provided by the embodiments of the present application is described in detail below through the examples shown in Figures 3 to 6. In the following examples, the first network element is an SMF and the second network element is an evaluation network element.

[0201] FIG3 shows an example of a communication method. In this example, UE1 accesses SAT 1, UE2 accesses SAT 2, SAT 1 deploys RAN 1 and UPF 1, and SAT 2 deploys RAN 2 and UPF 2. For example, the process of this example may include the following steps:

[0202] Step 300: The UE (including UE1 and UE2) executes a registration process, or a PDU session establishment process, or a service request process.

[0203] Optionally, based on device capabilities or contract information, when UE1 has a satellite switching service requirement in a satellite access scenario, it may send its own location information or motion trajectory information to the AMF during the execution of step 300, and the AMF may send the location information or motion trajectory information of UE1 or information of SAT 1 to the SMF. The location information may be positioning-related information such as longitude and latitude or global positioning system (GPS); the motion trajectory information may be a description of the speed and / or direction of movement, etc.

[0204] The information of SAT 1 may be the identification (ID) of RAN 1, the ID of UPF 1, or the ID of SAT 1. Typically, the ID of SAT 1 sent by the AMF to the SMF may be the ID of RAN 1. Optionally, if there is a mapping relationship between the ID of RAN 1 and the ID of SAT 1 in the AMF, the AMF may also send the ID of SAT 1 to the SMF.

[0205] The same is true for UE 2. You can refer to the content of UE 1, which will not be described in detail here.

[0206] If it is a PDU session establishment process or a service request process, SMF can obtain the UE-SAT-UE service indication from UDM or obtain the indication from the UE side or receive the indication from AMF.

[0207] Step 301: UE 1 initiates a voice call process (such as an Invite process) to UE 2.

[0208] Optionally, in the voice call process, UE 1 may send a UE-SAT-UE service indication to the P-CSCF. The UE-SAT-UE service is a service supported by the satellite transmission mode.

[0209] It should be understood that the voice call process may also be initiated by UE2 to UE1. This application only takes UE1 initiating as an example for explanation.

[0210] Step 302: The P-CSCF initiates a voice QoS flow establishment process.

[0211] In this process, the P-CSCF may send information of UE1 and UE2 to the PCF.

[0212] Optionally, the P-CSCF may also send a UE-SAT-UE service indication to the PCF. The UE-SAT-UE service indication may be based on the information received in step 301, or may be obtained by the P-CSCF from the UDM subscription data, or may be obtained based on the stored UE ID and the configuration information of the UE-SAT-UE service indication.

[0213] Step 303: The PCF sends the information of UE1 and UE2 to the SMF.

[0214] The information of UE1 and UE2 includes but is not limited to the identification of UE1 and UE2, calling and called conditions, AGW corresponding information, IP addresses of UE1 and UE2, etc.

[0215] Optionally, the PCF may also send a UE-SAT-UE service indication to the SMF.

[0216] Exemplarily, the PCF may send the above information to the SMF through the SMF policy association revision process.

[0217] Step 304: The SMF sends a first request to the evaluation network element based on the acquired UE-SAT-UE service indication information. The first request is used to request whether UE1 and UE2 communicate using satellite transmission.

[0218] The SMF may send a first request to the evaluation network element based on the information received from the PCF and the information obtained in step 300 .

[0219] For example, the first request may include identification information of SAT 1, identification information of SAT 2, information of UE1, and information of UE2.

[0220] Optionally, the first request may further include a UE-SAT-UE service indication.

[0221] The identification information of SAT 1 may be the ID of UPF 1 or the ID of RAN 1.

[0222] Optionally, when the SMF stores a mapping relationship between the UPF 1 ID and the RAN 1 ID, the identification information of SAT 1 may be the ID of UPF 1. When the SMF does not store a mapping relationship between the UPF 1 ID and the RAN 1 ID, the identification information of SAT 1 may be the ID of RAN 1. In this case, the evaluation network element may store a mapping relationship among the RAN 1 ID, the UPF 1 ID, and the SAT 1 ID.

[0223] Similarly, the identification information of SAT 2 may be the ID of UPF 2 or the ID of RAN 2.

[0224] Optionally, when the SMF stores a mapping relationship between the ID of UPF 2 and the ID of RAN 2, the identification information of SAT 2 may be the ID of UPF 2. When the SMF does not store a mapping relationship between the ID of UPF 2 and the ID of RAN 2, the identification information of SAT 2 may be the ID of RAN 2. In this case, the evaluation network element may store a mapping relationship among the ID of RAN 2, the ID of UPF 2, and the ID of SAT 2.

[0225] Optionally, when the interface with the evaluation network element is on a P-CSCF or PCF network element, the first request may be sent by the P-CSCF or PCF network element to the evaluation network element.

[0226] Step 305: The evaluation network element determines first indication information according to the first request and the first principle, where the first indication information is used to indicate that UE1 and UE2 communicate using satellite transmission, or the first indication information is used to indicate that UE1 and UE2 do not communicate using satellite transmission.

[0227] For a detailed description of the first principle, please refer to the relevant description in the embodiment shown in FIG2 , which will not be repeated here.

[0228] Step 306: The evaluation network element sends first indication information to the SMF.

[0229] Optionally, the evaluation network element stores the mapping relationship of all network nodes (RAN\UPF\SAT, etc.) and the topology distance relationship (RAN\UPF\SAT routing\GW, etc.).

[0230] When there is no mapping relationship between RAN 1's ID, UPF 1's ID and SAT 1's ID, and no mapping relationship between RAN 2's ID, UPF 2's ID and SAT 2's ID on the SMF, the evaluation network element may also send UPF 1's ID and UPF 2's ID to the SMF in step 306.

[0231] Optionally, when the evaluation network element determines that the paths based on SAT 1 and SAT 2 transmission are worse than the paths based on other satellite transmissions, the evaluation network element may determine a first transmission path and send information of the first transmission path (based on other satellite transmissions) to the SMF.

[0232] For example, when the transmission delay between UPF 1 and UPF 2 is greater than the transmission delay between UPF 3 and UPF 4, the evaluation network element may determine the first transmission path; and / or when the number of path nodes between UPF 1 and UPF 2 is greater than the number of path nodes between UPF 3 and UPF 4, the evaluation network element may determine the first transmission path. UPF 3 is located in SAT 3, and UPF 4 is located in SAT 4.

[0233] Accordingly, the information of the first transmission path may include the ID of UPF 3 and the ID of UPF 4.

[0234] Optionally, when the interface with the evaluation network element is on a P-CSCF or PCF network element, the first indication information is sent by the evaluation network element to the P-CSCF or PCF network element.

[0235] Step 307: When the first indication information is used to indicate that UE1 and UE2 communicate using satellite transmission, the SMF sends second indication information to the P-CSCF through the PCF. The second indication information is used to notify the P-CSCF that UE1 and UE2 communicate using satellite transmission.

[0236] That is, the P-CSCF is notified that in this case, the AGW network element is bypassed or detoured during satellite transmission communication, and the corresponding flow rule information of UE1 and UE2 sent to the AGW in step 301 can be updated.

[0237] Optionally, when the interface with the evaluation network element is on a P-CSCF or PCF network element, the second indication information is sent by the P-CSCF or PCF network element to the SMF network element.

[0238] Here, step 307 is optional.

[0239] Step 308: After the P-CSCF receives the second indication information, if there are subsequent requests for data detection or traffic billing, the P-CSCF negotiates with the 5GC regarding data detection or traffic billing.

[0240] Optionally, the specific content of the negotiation between the P-CSCF and the 5GC can be found in the aforementioned related descriptions and will not be described in detail here.

[0241] Step 309: When the first indication information is used to indicate that UE1 and UE2 communicate using satellite transmission, the SMF establishes a tunnel between SAT 1 and SAT 2, and sends the flow rules between UE1 and UE2 to UPF 1 and UPF 2; and / or, when the first indication information is used to indicate that UE1 and UE2 do not communicate using satellite transmission, the SMF sends the flow rules between UE1 and UE2 to the UPF on the ground.

[0242] The SMF can send messages through the satellite interface to trigger the establishment of a tunnel between SAT 1 and SAT 2. The tunnel between SAT 1 and SAT 2 is also the tunnel between UPF 1 and UPF 2. The SMF can also create tunnels between UPF 1 and RAN 1, and between UPF 2 and RAN 2.

[0243] For example, the flow rule may indicate that when the traffic of UE1-UE2 is sent to RAN1, it is forwarded to UPF1 and then forwarded to UPF2 through the tunnel between UPF1 and UPF2, and then sent to RAN2.

[0244] Optionally, if in step 306, the SMF also receives information about the first transmission path, then in step 309, when the first indication information is used to indicate that UE1 and UE2 communicate using satellite transmission, the SMF sends a message through the interface between the satellite to trigger the establishment of a tunnel between SAT 1 and SAT 2, that is, a tunnel between UPF1 and UPF2, and a tunnel between UPF and RAN, and sends the flow rules between UE1 and UE2 to UPF 3 and UPF 4.

[0245] Step 310: When the first indication information is used to instruct UE1 and UE2 to communicate using satellite transmission, UE1 and UE2 communicate using satellite transmission.

[0246] The communication path between UE1 and UE2 using satellite transmission may be UE1-(RAN1)SAT1(UPF1)-(UPF2)SAT2(RAN2)-UE2.

[0247] Optionally, if SMF establishes a tunnel between SAT 3 and SAT 4 in step 309, the communication path between UE1 and UE2 using satellite transmission can be UE1-(RAN 1)SAT 3(UPF 3)-(UPF 4)SAT 4(RAN 2)-UE2.

[0248] Based on the above example, the evaluation network element evaluates whether UE1 and UE2 communicate using satellite transmission, thereby accurately determining a more appropriate communication mode between UE1 and UE2 and improving communication efficiency.

[0249] If, during the data transmission process (e.g., a call process) between UE1 and UE2 based on the example shown in FIG3 , the satellite access situation of UE1 and / or UE2 changes, that is, the UE access has a satellite handover situation, the SMF needs to re-request from the evaluation network element whether UE1 and UE2 communicate using satellite transmission. Based on this, FIG4 shows an example of another communication method. In this example, UE1 initially accesses SAT 1, UE2 accesses SAT 2, SAT 1 deploys RAN 1 and UPF 1, SAT 2 deploys RAN 2 and UPF 2, and UE2 switches to SAT 3. Exemplarily, the process of this example may include the following steps:

[0250] Step 400: When UE1 and UE2 are in a call, UE2 perceives that the access satellite of UE2 will be switched from SAT 2 where RAN2 is located to SAT 3 where RAN3 is located based on the signal strength of RAN2 and RAN3, and notifies RAN2 of the information of RAN3, entering the switching preparation phase. In the switching preparation phase, RAN2 on SAT2 sends a switching request to AMF. The switching request is used to request switching from SAT2 to SAT3. After receiving the switching request, AMF sends a PDU session context update request to SMF. The PDU session context update request contains the information of RAN 3 on SAT3. SMF selects UPF3 corresponding to RAN3 based on the PDU session context update request, and then SMF obtains the information of SAT 3 that UE2 is about to access.

[0251] Among them, UE2 perceives that the access satellite of UE2 will be switched from SAT 2 to SAT 3 based on the signal strength of RAN2 and RAN3. Specifically, UE2 perceives that the signal strength between UE2 and RAN3 on SAT3 is greater than the signal strength between UE2 and RAN2 on SAT2. UE2 can perceive that the access satellite of UE2 will be switched from SAT 2 to SAT 3.

[0252] In the handover accuracy phase, before RAN2 on SAT2 sends a handover request to AMF, RAN2 obtains information about RNA3 from UE2. Furthermore, the handover request may include information about RAN3.

[0253] The first indication information obtained by the SMF from the evaluation network element before indicates that the communication between UE2 and UE1 is carried out by satellite transmission, or the SMF obtains from the UDM or UE side during the initial PDU session establishment process or service request process that UE1 and UE2 have a UE-SAT-UE service indication or service contract. Then, when the SMF receives the PDU session context update request and obtains the SAT3 information, and thus determines that a satellite switching occurs, the SMF will execute step 401.

[0254] Step 401: The SMF sends a fourth request to the evaluation network element. The fourth request is used to request whether UE1 and UE2 communicate using satellite transmission.

[0255] Step 401 is similar to step 304 and can be referred to each other, so it will not be described in detail here. It should be understood that step 401 is different from step 304 in that the fourth request no longer contains the identification information of SAT 2, but the identification information of SAT 3.

[0256] Step 402: The evaluation network element determines fourth indication information based on the fourth request and the first principle, where the fourth indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, or to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission.

[0257] Among them, step 402 is similar to step 305, and they can refer to each other, and will not be described in detail here.

[0258] Step 403: The evaluation network element sends fourth indication information to the SMF.

[0259] Among them, step 403 is similar to step 306, and they can refer to each other, and will not be described in detail here.

[0260] Step 404: When the fourth indication information indicates that satellite transmission is used for communication between the first terminal device and the second terminal device, the SMF establishes a tunnel between SAT 1 and SAT 3. When the fourth indication information indicates that satellite transmission is not used for communication between the first terminal device and the second terminal device, the SMF deletes the tunnel between SAT 1 and SAT 2. Both tunnel establishment and deletion are performed on the inter-satellite network element after signaling is exchanged between the SMF and the interface between the inter-satellite network element.

[0261] Optionally, in the case where UE1 and UE2 previously communicated using satellite transmission, when the fourth indication information is used to indicate that satellite transmission is not used for communication between the first terminal device and the second terminal device, the SMF element deletes the tunnel between SAT 1 and SAT 2 and selects the UPF on the ground for communication.

[0262] For example, SMF can perform the PDU session creation process with the UPF on the ground for the service between UE1 and UE2, and the UPF on the ground creates corresponding tunnels and flow rules for the corresponding UE; SMF notifies the UPF on SA1 and SAT2 to perform the N4 session release process, and the tunnels and flow rules created by UPF1 and UPF2 for the corresponding UE will be deleted accordingly.

[0263] Based on this example, in a satellite handover scenario, the evaluation network element can re-evaluate whether UE1 and UE2 communicate using satellite transmission, thereby accurately determining a more appropriate communication method between UE1 and UE2 and improving communication efficiency.

[0264] FIG5 shows another example of a communication method. In this example, UE1 accesses SAT 1, UE2 accesses SAT 2, SAT 1 deploys RAN 1, UPF 1, and AGW 1, and SAT 2 deploys RAN 2, UPF 2, and AGW 2. For example, the process of this example may include the following steps:

[0265] Step 500 is similar to step 300 and can refer to each other, so it will not be repeated here.

[0266] Step 501: UE 1 initiates a voice call process (such as an Invite process) to UE 2.

[0267] Optionally, in the voice call process, UE 1 may send a UE-SAT-UE service indication to the P-CSCF.

[0268] It should be understood that the voice call process may also be initiated by UE2 to UE1. This application only takes UE1 initiating as an example for explanation.

[0269] In the voice call process, the P-CSCF may determine that the AGW is deployed on the satellite. Optionally, the P-CSCF may also determine a mapping relationship between the AGW ID and the SAT ID (or the RAN or UPF ID).

[0270] Optionally, when the calling and called P-CSCFs are not the same network element, the AGW is located on the satellite. The calling P-CSCF selects AGW1 for the calling party during INVITE, and the called P-CSCF selects AGW2 for the called party. The called P-CSCF has the UE IP addresses of the calling and called party, and can determine whether both AGWs are on the satellite and whether they can support the preliminary evaluation of UE-SAT-UE.

[0271] Step 502: The P-CSCF initiates a voice QoS flow establishment process.

[0272] In this process, the P-CSCF may send information of UE1 and UE2 to the PCF. The corresponding information is shown in step 303. At this time, the information of UE1 and UE2 should include information of AGW1 and AGW2.

[0273] Optionally, the P-CSCF may also send a UE-SAT-UE service indication to the PCF. The source of the UE-SAT-UE service indication may be found in the description of step 302, and will not be described in detail here.

[0274] Optionally, the P-CSCF may also send information to the PCF indicating that the AGW is deployed on a satellite.

[0275] Optionally, the P-CSCF may also send the ID of AGW 1 and the ID of AGW 2 to the PCF.

[0276] Step 503: The PCF sends the information of UE1 and UE2 to the SMF.

[0277] Optionally, the PCF may also send a UE-SAT-UE service indication to the SMF.

[0278] Optionally, the PCF may also send information to the SMF indicating that the AGW is deployed on the satellite.

[0279] Optionally, the PCF may also send the ID of AGW 1 and the ID of AGW 2 to the SMF.

[0280] Exemplarily, the PCF may send the above information to the SMF through the SMF policy association revision process.

[0281] Step 504: The SMF sends a first request to the evaluation network element. The first request is used to request whether UE1 and UE2 communicate using satellite transmission.

[0282] The SMF may send a first request to the evaluation network element based on the information received from the PCF and the information obtained in step 500 .

[0283] For example, the first request may include identification information of SAT 1, identification information of SAT 2, information of UE1, and information of UE2.

[0284] Optionally, the first request may further include a UE-SAT-UE service indication.

[0285] The identification information of SAT 1 may be the ID of UPF 1 or the ID of RAN 1 or the ID of AGW 1.

[0286] Optionally, when the SMF stores a mapping relationship between the UPF 1 ID and the RAN 1 ID, the identification information of SAT 1 may be the ID of UPF 1. When the SMF does not store a mapping relationship between the UPF 1 ID and the RAN 1 ID, the identification information of SAT 1 may be the ID of RAN 1. In this case, the evaluation network element may store a mapping relationship among the RAN 1 ID, the UPF 1 ID, and the SAT 1 ID.

[0287] Similarly, the identification information of SAT 2 may be the ID of UPF 2 or the ID of RAN 2 or the ID of AGW 2.

[0288] Optionally, when the SMF stores a mapping relationship between the ID of UPF 2 and the ID of RAN 2, the identification information of SAT 2 may be the ID of UPF 2. When the SMF does not store a mapping relationship between the ID of UPF 2 and the ID of RAN 2, the identification information of SAT 2 may be the ID of RAN 2. In this case, the evaluation network element may store a mapping relationship among the ID of RAN 2, the ID of UPF 2, and the ID of SAT 2.

[0289] Optionally, when the interface with the evaluation network element is on a P-CSCF or PCF network element, the first request is sent by the P-CSCF or PCF network element to the evaluation network element.

[0290] Step 505: The evaluation network element determines first indication information according to the first request and the first principle, where the first indication information is used to indicate that UE1 and UE2 communicate using satellite transmission, or the first indication information is used to indicate that UE1 and UE2 do not communicate using satellite transmission.

[0291] For a detailed description of the first principle, please refer to the relevant description in the embodiment shown in FIG2 , which will not be repeated here.

[0292] If the identification information of SAT 1 obtained by the evaluation network element in step 504 is the ID of UPF 1 and / or the ID of AGW 1, and the identification information of SAT 2 is the ID of UPF 2 and / or the ID of AGW 2, when the relationship between AGW and UPF is not one-to-one corresponding, that is, when the evaluation network element determines that the path based on SAT 1 and SAT 2 transmission is worse than the path based on other satellite transmission, the evaluation network element can determine a first transmission path, which is a path based on other satellite transmission.

[0293] Step 506: The evaluation network element sends first indication information to the SMF.

[0294] Optionally, the evaluation network element stores the mapping relationship of all network nodes (RAN\UPF\SAT, etc.) and the topology distance relationship (RAN\UPF\SAT routing\GW, etc.).

[0295] Optionally, in step 506, the evaluation network element may also send the ID of UPF 1, the ID of AGW 1, the ID of AGW 2 and the ID of UPF 2 to the SMF.

[0296] Optionally, when the evaluation network element determines the first transmission path, information about the first transmission path may be sent to the SMF.

[0297] For example, the evaluation network element may determine the first transmission path when the transmission delay between UPF 1, AGW 1, UPF 2, and AGW 2 is greater than the transmission delay between UPF 3, AGW 3, UPF 4, and AGW 4; and / or when the number of path nodes between UPF 1, AGW 1, UPF 2, and AGW 2 is greater than the number of path nodes between UPF 3, AGW 3, UPF 4, and AGW 4, the evaluation network element may determine the first transmission path. UPF 3 and AGW 3 are located in SAT 3, and UPF 4 and AGW 4 are located in SAT 4.

[0298] Accordingly, the information of the first transmission path may include the ID of the UPF 3 , the ID of the AGW 3 , the ID of the UPF 4 , and the ID of the AGW 4 .

[0299] Optionally, when the interface with the evaluation network element is on a P-CSCF or PCF network element, the first indication information is sent by the evaluation network element to the P-CSCF or PCF network element.

[0300] Step 507: When the first indication information is used to indicate that UE1 and UE2 communicate using satellite transmission, the SMF sends second indication information to the P-CSCF through the PCF, where the second indication information is used to indicate that UE1 and UE2 communicate using satellite transmission.

[0301] Optionally, if in step 507, the evaluation network element sends information about the first transmission path to the SMF, the SMF may request the P-CSCF to adopt the first transmission path based on the information about the first transmission path; further, the SMF determines whether to adopt the first transmission path based on the P-CSCF's response to the request.

[0302] When the SMF requests the P-CSCF to adopt the first transmission path according to the information of the first transmission path, the SMF may send the ID of AGW 3 and the ID of AGW 4 to the P-CSCF.

[0303] Optionally, when the interface with the evaluation network element is on a P-CSCF or PCF network element, the second indication information is sent by the P-CSCF or PCF network element to the SMF.

[0304] Step 508: After the P-CSCF receives the second indication information and the ID of AGW 3 and the ID of AGW 4, if the loads of AGW 3 and AGW 4 are both less than or equal to the first load threshold, the P-CSCF confirms that on-satellite or inter-satellite switching can be performed and sends the ID of AGW 3 and the ID of AGW 4 to the SMF; if the load of at least one of AGW 3 and AGW 4 is greater than the first load threshold, the P-CSCF sends the IDs of the AGWs other than the ID of AGW 3 and AGW 4 to the SMF.

[0305] Optionally, when the calling and called parties are not managed by the same P-CSCF, media renegotiation is required during the INVITE process to update the AGW. The called P-CSCF determines whether the calling and called party's AGWs are both on-board and can support UE-SAT-UE communication.

[0306] Optionally, when the P-CSCF sends the aforementioned ID to the SMF, the P-CSCF sends it to the SMF through the PCF.

[0307] Step 509 : When the P-CSCF determines that the loads of AGW 3 and AGW 4 are both less than or equal to the first load threshold, the P-CSCF sends the flow rules of UE1 and UE2 to AGW 3 and AGW 4 .

[0308] Among them, step 508 and step 509 are optional.

[0309] Step 510: When the first indication information is used to indicate that UE1 and UE2 communicate using satellite transmission, the SMF sends the flow rules between UE1 and UE2 to UPF 1 and UPF 2, and the flow rules may indicate that the traffic between UE1 and UE2 is forwarded along the path of the satellite transmission, and sends the flow rules between UE1 and UE2 to AGW 1 and AGW 2 through the PCF to the P-CSCF; and / or, when the first indication information is used to indicate that UE1 and UE2 do not communicate using satellite transmission, the SMF sends the flow rules between UE1 and UE2 to the UPF on the ground.

[0310] Optionally, when the SMF also receives information about the first transmission path and receives the ID of AGW 3 and the ID of AGW 4 from the P-CSCF, that is, when the aforementioned first transmission path is adopted, the SMF sends the flow rules between UE1 and UE2 to UPF 3 and UPF 3, and sends the flow rules between UE1 and UE2 to AGW 3 and AGW 3.

[0311] Optionally, the SMF also receives information about the first transmission path, and when the SMF receives information from the P-CSCF other than the ID of AGW 3 and the ID of AGW 4, the SMF may send a second request to the evaluation network element, where the second request is used to request whether UE1 and UE2 communicate using satellite transmission; further, the SMF receives third indication information from the evaluation network element, where the third indication information is used to indicate that UE1 and UE2 communicate using satellite transmission, or the third indication information is used to indicate that UE1 and UE2 do not communicate using satellite transmission.

[0312] Step 511: When the first indication information is used to instruct UE1 and UE2 to communicate using satellite transmission, UE1 and UE2 communicate using satellite transmission.

[0313] The communication path between UE1 and UE2 using satellite transmission may be UE1-(RAN1)SAT1(UPF1-AGW1)-(AGW2--UPF2)SAT2(RAN2)-UE2.

[0314] Optionally, if in step 510, the SMF sends the flow rules between UE1 and UE2 to UPF 3 and UPF 3, and sends the flow rules between UE1 and UE2 to AGW 3 and AGW 3, the communication path between UE1 and UE2 using satellite transmission can be UE1-(RAN 1)SAT3(UPF 3-AGW 3)-(AGW 4-UPF 4)SAT 4(RAN 2)-UE2.

[0315] Based on the above example, the evaluation network element evaluates whether UE1 and UE2 communicate using satellite transmission, thereby accurately determining a more appropriate communication mode between UE1 and UE2 and improving communication efficiency.

[0316] If, during the data transmission process (e.g., a call process) between UE1 and UE2 based on the example shown in Figure 5, satellite handover occurs to UE1 and / or UE2, the SMF needs to re-request from the evaluation network element whether UE1 and UE2 should communicate using satellite transmission. Based on this, Figure 6 shows an example of another communication method. In this example, UE1 initially accesses SAT 1, UE2 accesses SAT 2, SAT 1 deploys RAN 1, UPF 1, and AGW 1, SAT 2 deploys RAN 2, UPF 2, and AGW 2, and UE2 switches to SAT 3.

[0317] Exemplarily, the process of this example may include the following steps:

[0318] Step 600 is similar to step 400 and can refer to each other, so it will not be repeated here.

[0319] Step 601: The SMF sends a fourth request to the evaluation network element. The fourth request is used to request whether UE1 and UE2 communicate using satellite transmission.

[0320] Optionally, based on the obtained UE-SAT-UE service indication of UE1 and UE2 and the information on the AGW satellite, the SMF may skip steps 601 to 603 and directly send the fourth request or switching indication information to the P-CSCF to trigger the P-CSCF to perform step 605 and notify the UE side to initiate a voice call process.

[0321] Step 601 is similar to step 504 and can be referred to each other, so it will not be described in detail here. It should be understood that the difference between step 601 and step 504 is that the fourth request no longer contains the identification information of SAT 2, but the identification information of SAT 3.

[0322] Step 602: The evaluation network element determines fourth indication information based on the fourth request and the first principle, where the fourth indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, or to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission.

[0323] Among them, step 602 is similar to step 505, and they can refer to each other, and will not be described in detail here.

[0324] Step 603: The evaluation network element sends fourth indication information to the SMF.

[0325] Among them, step 603 is similar to step 506, and they can refer to each other, and will not be described in detail here.

[0326] Step 604: When the fourth indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, and the SMF determines that the AGW is deployed on SAT 3, the SMF sends a switching indication to the P-CSCF, and the switching indication is used to indicate the path switching between UE1 and UE2.

[0327] Optionally, the SMF may also send fourth indication information and / or information of UE1 and UE2 to the P-CSCF.

[0328] Step 605: The P-CSCF sends first information to UE1 or UE2 according to the handover instruction. The first information is used to initiate a voice call process (such as an Invite process).

[0329] Afterwards, the process shown in step 502 to step 511 shown in FIG5 is executed again.

[0330] Based on this example, in a satellite handover scenario, the evaluation network element can re-evaluate whether UE1 and UE2 communicate using satellite transmission, thereby accurately determining a more appropriate communication method between UE1 and UE2 and improving communication efficiency.

[0331] Based on the above embodiments, the present application also provides a communication device. Referring to FIG7 , the communication device 700 may include a transceiver unit 701 and a processing unit 702. The transceiver unit 701 is used for the communication device 700 to communicate, such as receiving information (messages or data) or sending information (messages or data), and the processing unit 702 is used to control and manage the actions of the communication device 700. The processing unit 702 may also control the steps performed by the transceiver unit 701.

[0332] The communication device 700 may be the aforementioned second network element, or a processor, chip, chip system, or functional module in the second network element. Alternatively, the communication device 700 may be the aforementioned first network element, or a processor, chip, chip system, or functional module in the first network element. Alternatively, the communication device 700 may be the aforementioned proxy call session control function network element, or a processor, chip, chip system, or functional module in the proxy call session control function network element.

[0333] In one embodiment, when the communication device 700 functions as the second network element in the aforementioned embodiment, the transceiver unit 701 may be configured to receive a first request from the first network element, the first request being configured to request whether a first terminal device and a second terminal device communicate using a satellite transmission method; the first terminal device accesses a first satellite, and the second terminal device accesses a second satellite; the processing unit 702 may be configured to send first indication information to the first network element based on the first request, the first indication information being configured to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method, or the first indication information being configured to indicate that the first terminal device and the second terminal device do not communicate using a satellite transmission method. The processing unit 702 may also be configured to control the transceiver unit 701's transceiver operations.

[0334] In an optional embodiment, the first request includes one or more of the following: identification information of the first satellite, identification information of the second satellite, information of the first terminal device, information of the second terminal device, or information on the need for communication between the first terminal device and the second terminal device using satellite transmission.

[0335] Exemplarily, the identification information of the first satellite is an identifier of a first user plane function network element, an identifier of a first access network device, an identifier of a first access gateway, or an identifier of the first satellite, and at least one of the first user plane function network element, the first access network device, and the first access gateway is located on the first satellite and provides services for the first terminal device;

[0336] The identification information of the second satellite is an identifier of a second user plane function network element, an identifier of a second access network device, an identifier of a second access gateway, or an identifier of the second satellite. At least one of the second user plane function network element, the second access network device, and the second access gateway is located on the second satellite and provides services for the second terminal device.

[0337] Optionally, the information of the first terminal device includes one or more of the following: an identifier of the first terminal device, an Internet Protocol IP address of the first terminal device, location information of the first terminal device, a movement trajectory of the first terminal device, or identification information of the first satellite;

[0338] The information of the second terminal device includes one or more of the following: an identifier of the second terminal device, an IP address of the second terminal device, location information of the second terminal device, a movement trajectory of the second terminal device, or identification information of the second satellite.

[0339] In one possible embodiment, when the processing unit 702 sends the first indication information to the first network element according to the first request, it can be used to: determine the first indication information according to the first request and the first principle, and control the transceiver unit 701 to send the first indication information to the first network element.

[0340] In one example, the first principle includes one or more of the following:

[0341] If the delay of communication between the first terminal device and the second terminal device using satellite transmission is less than the delay of communication between the first terminal device and the second terminal device using terrestrial transmission, the first terminal device and the second terminal device communicate with each other using satellite transmission; or

[0342] If the number of path nodes for communication between the first terminal device and the second terminal device using satellite transmission is less than the number of path nodes for communication between the first terminal device and the second terminal device using terrestrial transmission, the first terminal device and the second terminal device communicate using satellite transmission; or

[0343] If the time delay for communication between the first terminal device and the second terminal device using satellite transmission is less than the time delay for communication between the first terminal device and the second terminal device using terrestrial transmission, and the movement directions of the first satellite and the second satellite are consistent, and the time delay for communication between the first terminal device and the second terminal device using satellite transmission is greater than or equal to the first time delay, then the first terminal device and the second terminal device communicate using satellite transmission; or

[0344] The number of path nodes for communication between the first terminal device and the second terminal device using satellite transmission is less than the number of path nodes for communication between the first terminal device and the second terminal device using ground transmission, and the movement directions of the first satellite and the second satellite are consistent, and the number of path nodes for communication between the first terminal device and the second terminal device using satellite transmission is less than or equal to a first node number threshold, then the first terminal device and the second terminal device communicate using satellite transmission.

[0345] In some embodiments, the transceiver unit 701 may also be used to send information about a first transmission path to the first network element, where the first transmission path is used for communication between the first terminal device and the second terminal device using satellite transmission.

[0346] Optionally, the processing unit 702 may further be configured to: determine the first transmission path when the transmission delay between the first user plane function network element and the second user plane function network element is greater than the transmission delay between the third user plane function network element and the fourth user plane function network element; wherein the first user plane function network element is located on the first satellite, the second user plane function network element is located on the second satellite, the third user plane function network element is located on the third satellite, and the fourth user plane function network element is located on the fourth satellite; or

[0347] When the transmission delay between the first user plane function network element, the first access gateway, the second access gateway, and the second user plane function network element is greater than the transmission delay between the third user plane function network element, the third access gateway, the fourth access gateway, and the fourth user plane function network element, determining the first transmission path; wherein the first user plane function network element and the first access gateway are located on the first satellite, the second user plane function network element and the second access gateway are located on the second satellite, the third user plane function network element and the third access gateway are located on the third satellite, and the fourth user plane function network element and the fourth access gateway are located on the fourth satellite.

[0348] The information of the first transmission path may include: an identifier of a third user plane function network element and an identifier of a fourth user plane function network element; wherein the third user plane function network element is located on a third satellite, and the fourth user plane function network element is located on a fourth satellite;

[0349] Alternatively, the information of the first transmission path may include: an identifier of the third user plane function network element and an identifier of the fourth user plane function network element, as well as an identifier of a third access gateway and an identifier of a fourth access gateway; wherein the third user plane function network element and the third access gateway are located on the third satellite, and the fourth user plane function network element and the fourth access gateway are located on the fourth satellite.

[0350] Optionally, the first network element is a session management function network element, a policy control function network element, or a proxy call session control function network element.

[0351] In another embodiment, when the communication device 700 functions as the first network element in the aforementioned embodiment, the transceiver unit 701 may be configured to send a first request to a second network element, the first request being configured to request whether a satellite transmission method is used for communication between a first terminal device and a second terminal device; the first terminal device accessing a first satellite and the second terminal device accessing a second satellite; and receive first indication information from the second network element, the first indication information being configured to indicate that a satellite transmission method is used for communication between the first terminal device and the second terminal device, or the first indication information being configured to indicate that a satellite transmission method is not used for communication between the first terminal device and the second terminal device. The processing unit 702 may be configured to control the operation of the transceiver unit 701.

[0352] In an optional implementation, the first network element is a session management function network element, and the transceiver unit 701 may be further configured to: when the first indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission mode, send the data forwarding rules of the first terminal device and the second terminal device to the first user plane function network element and the second user plane function network element; the first user plane function network element is located on the first satellite, and the second user plane function network element is located on the second satellite; and / or

[0353] When the first indication information is used to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission, the data forwarding rules for the first terminal device and the second terminal device are sent to a user plane functional network element located on the ground.

[0354] Exemplarily, the first request includes one or more of the following: identification information of the first satellite, identification information of the second satellite, information of the first terminal device, information of the second terminal device, or information on the need for communication between the first terminal device and the second terminal device using satellite transmission.

[0355] Optionally, the identification information of the first satellite is an identifier of a first user plane function network element, an identifier of a first access network device, an identifier of a first access gateway, or an identifier of the first satellite, and at least one of the first user plane function network element, the first access network device, and the first access gateway is located on the first satellite and provides services for the first terminal device;

[0356] The identification information of the second satellite is an identifier of a second user plane function network element, an identifier of a second access network device, an identifier of a second access gateway, or an identifier of the second satellite. At least one of the second user plane function network element, the second access network device, and the second access gateway is located on the second satellite and provides services for the second terminal device.

[0357] In one example, the information of the first terminal device includes one or more of the following: an identifier of the first terminal device, an Internet Protocol IP address of the first terminal device, location information of the first terminal device, a movement trajectory of the first terminal device, or identification information of the first satellite;

[0358] The information of the second terminal device includes one or more of the following: an identifier of the second terminal device, an IP address of the second terminal device, location information of the second terminal device, a movement trajectory of the second terminal device, or identification information of the second satellite.

[0359] In some embodiments, the first network element is a session management function network element, and the transceiver unit 701 can also be used to: when the first indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method, send second indication information to the proxy call session control function network element through the policy control function network element, and the second indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method.

[0360] Optionally, the first network element is a session management function network element, and the processing unit 702 can also be used to: when the first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, establish a tunnel between the first satellite and the second satellite.

[0361] In some embodiments, when the first network element is a session management function network element and the first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, the transceiver unit 701 can also be used to: send data forwarding rules between the first terminal device and the second terminal device to the first access gateway and the second access gateway.

[0362] Optionally, the transceiver unit 701 can also be used to receive the identifier of the first access gateway and the identifier of the second access gateway from a proxy call session control function network element or from a policy control function network element; further, when the transceiver unit 701 sends the data forwarding rules between the first terminal device and the second terminal device to the first access gateway and the second access gateway, it can be used to: send the data forwarding rules between the first terminal device and the second terminal device to the first access gateway according to the identifier of the first access gateway; send the data forwarding rules between the first terminal device and the second terminal device to the second access gateway according to the identifier of the second access gateway.

[0363] In some embodiments, the transceiver unit 701 may also be used to: receive information about a first transmission path from the second network element, where the first transmission path is used for communication between the first terminal device and the second terminal device using satellite transmission.

[0364] In one example, the first network element is a session management function network element, and the information of the first transmission path includes an identifier of a third user plane function network element and an identifier of a fourth user plane function network element, wherein the third user plane function network element is located on a third satellite, and the fourth user plane function network element is located on a fourth satellite. The processing unit 702 can also be used to: when the first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, establish a tunnel between the third satellite and the fourth satellite according to the information of the first transmission path.

[0365] In another example, the first network element is a session management function network element, and the information of the first transmission path includes: an identifier of a third user plane function network element, an identifier of a fourth user plane function network element, and an identifier of a third access gateway, and an identifier of a fourth access gateway; wherein the third user plane function network element and the third access gateway are located on the third satellite, and the fourth user plane function network element and the fourth access gateway are located on the fourth satellite. The processing unit 702 may further be configured to: when the first indication information is used to indicate that communication between the first terminal device and the second terminal device is performed using a satellite transmission mode, request, based on the information of the first transmission path, a proxy call session control function network element to adopt the first transmission path; and determine, based on a response of the proxy call session control function network element to the request, whether to adopt the first transmission path.

[0366] Optionally, when the processing unit 702 requests the proxy call session control function network element to adopt the first transmission path according to the information of the first transmission path, it can be used to: control the transceiver unit 701 to send the identifier of the third access gateway and the identifier of the fourth access gateway to the proxy call session control function network element;

[0367] When the processing unit 702 determines whether to adopt the first transmission path according to the response of the proxy call session control function network element to the request, it can be configured to:

[0368] If the first network element receives the identifier of the third access gateway and the identifier of the fourth access gateway from the proxy call session control function network element, determining to use the first transmission path; and / or,

[0369] If the first network element receives access gateway identifiers other than the identifier of the third access gateway and the identifier of the fourth access gateway from the proxy call session control function network element, it is determined not to use the first transmission path.

[0370] In an optional embodiment, the transceiver unit 701 can also be used to: when the processing unit 702 determines not to adopt the first transmission path, send a second request to the second network element, the second request being used to request whether the first terminal device and the second terminal device communicate using satellite transmission; and receive third indication information from the second network element, the third indication information being used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, or the third indication information being used to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission.

[0371] In some embodiments, the first network element is a proxy call session control function network element, and the information of the first transmission path includes an identifier of a third user plane function network element, an identifier of the fourth user plane function network element, and an identifier of a third access gateway and an identifier of a fourth access gateway, wherein the third user plane function network element and the third access gateway are located on a third satellite, and the fourth user plane function network element and the fourth access gateway are located on a fourth satellite. When the first indication information is used to indicate that satellite transmission is used for communication between the first terminal device and the second terminal device, the transceiver unit 701 may further be configured to: when loads of the third access gateway and the fourth access gateway are both less than or equal to a first load threshold, send the identifier of the third access gateway, the identifier of the fourth access gateway, and the first indication information to the session management function network element; or when the load of at least one of the third access gateway and the fourth access gateway is greater than the first load threshold, send a third request to the second network element, the third request being used to request whether satellite transmission is used for communication between the first terminal device and the second terminal device.

[0372] Optionally, the first network element is a proxy call session control function network element or a policy control function network element, and the transceiver unit 701 may also be configured to send the first indication information to a session management function network element.

[0373] In one possible embodiment, when satellite switching occurs in the first terminal device and / or the second terminal device, the transceiver unit 701 can also be used to send a fourth request to the second network element, and the fourth request is used to request whether the first terminal device and the second terminal device communicate using satellite transmission; and receive fourth indication information from the second network element, and the fourth indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, or to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission.

[0374] In some embodiments, the first network element is a session management function network element, and the processing unit 702 can also be used to: when the fourth indication information is used to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission, delete the tunnel between the first satellite and the second satellite.

[0375] Optionally, the first network element is a session management function network element, and the transceiver unit 701 can also be used to: when the fourth indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, and an access gateway is deployed on the target satellite of the terminal device where satellite switching occurs, send a switching indication to the proxy call session control function network element, and the switching indication is used to indicate the path switching between the first terminal device and the second terminal device.

[0376] In another embodiment, when the communication device 700 is used to perform the function of the proxy call session control function network element in the aforementioned embodiment, the processing unit 702 can be used to determine a first target access gateway and a second target access gateway, where the first target access gateway and the second target access gateway are used for communication between a first terminal device and a second terminal device using a satellite transmission method; the first terminal device accesses a first satellite, and the second terminal device accesses a second satellite; the transceiver unit 701 can be used to send an identifier of the first target access gateway and an identifier of the second target access gateway to the session management function network element.

[0377] In one example, when determining the first target access gateway and the second target access gateway, the processing unit 702 can be used to: determine the first target access gateway and the second target access gateway based on the ephemeris information and the information of the first terminal device and the information of the second terminal device; or, control the transceiver unit 701 to obtain the identifier of the first target access gateway and the identifier of the second target access gateway from the evaluation network element.

[0378] In another example, the transceiver unit 701 can also be used to receive second indication information from the session management function network element, where the second indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission; when determining the first target access gateway and the second target access gateway, the processing unit 702 can be used to: if the loads of the first access gateway and the second access gateway are both less than or equal to the first load threshold, determine the first target access gateway as the first access gateway and the second target access gateway as the second access gateway according to the second indication information; wherein, the first access gateway is located on the first satellite and the second access gateway is located on the second satellite.

[0379] In another example, the transceiver unit 701 can also be used to receive the identifier of the third access gateway and the identifier of the fourth access gateway from the session management function network element, where the third access gateway is located on the third satellite and the fourth access gateway is located on the fourth satellite; when determining the first target access gateway and the second target access gateway, the processing unit 702 can be used to: if the loads of the third access gateway and the fourth access gateway are both less than or equal to the first load threshold, determine that the first target access gateway is the third access gateway and the second target access gateway is the fourth access gateway.

[0380] Optionally, the transceiver unit 701 can also be used to receive a switching indication from the session management function network element, and the switching indication is used to indicate the path switching between the first terminal device and the second terminal device; according to the switching indication, send first information to the first terminal device or the second terminal device, and the first information is used to initiate a voice call process.

[0381] It should be noted that the division of units in the embodiments of the present application is schematic and is merely a logical functional division. In actual implementation, other division methods may be used. The functional units in the embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0382] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0383] Based on the above embodiments, embodiments of the present application further provide a communication device. Referring to FIG8 , the communication device 800 may include one or more processors 802. Optionally, the communication device 800 may further include a transceiver 801. Optionally, the communication device 800 may further include at least one memory 803. The memory 803 may be located within or outside the communication device 800. The processor 802 may control the transceiver 801 to receive and send information, messages, or data.

[0384] Specifically, the processor 802 may be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and an NP. The processor 802 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0385] The transceiver 801, the processor 802, and the memory 803 are interconnected. Optionally, the transceiver 801, the processor 802, and the memory 803 are interconnected via a bus 804; the bus 804 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus may be classified as an address bus, a data bus, a control bus, or the like. For ease of illustration, FIG8 shows only one thick line, but this does not imply that there is only one bus or only one type of bus.

[0386] In an optional embodiment, the memory 803 is used to store programs, etc. Specifically, the programs may include program code, which includes computer operating instructions. The memory 803 may include RAM, or may also include non-volatile memory (non-volatile memory), such as one or more disk storage devices. The processor 802 executes the application stored in the memory 803 to implement the above functions, thereby realizing the functions of the communication device 800.

[0387] Exemplarily, the communication device 800 may specifically implement the functions of the first network element, the second network element, or the proxy call session control function network element in the above embodiments.

[0388] In one embodiment, when the communication device 800 implements the functions of the second network element in the aforementioned method embodiment, the transceiver 801 may implement the transceiver operations performed by the second network element in the aforementioned method embodiment; and the processor 802 may implement other operations performed by the second network element in the aforementioned method embodiment in addition to the transceiver operations. For specific related descriptions, please refer to the relevant descriptions in the aforementioned method embodiment and will not be described in detail here.

[0389] In another embodiment, when the communication device 800 implements the functions of the first network element in the aforementioned method embodiment, the transceiver 801 may implement the transceiver operations performed by the first network element in the aforementioned method embodiment; and the processor 802 may implement other operations performed by the first network element in the aforementioned method embodiment except for the transceiver operations. For specific related descriptions, please refer to the relevant descriptions in the aforementioned method embodiment and will not be described in detail here.

[0390] In another embodiment, when the communication device 800 implements the functions of the proxy call session control function network element in the aforementioned method embodiment, the transceiver 801 may implement the transceiver operations performed by the proxy call session control function network element in the aforementioned method embodiment; and the processor 802 may implement other operations performed by the proxy call session control function network element in the aforementioned method embodiment, except for the transceiver operations. For specific details, please refer to the relevant descriptions in the aforementioned method embodiment and will not be described in detail here.

[0391] Based on the above embodiments, an embodiment of the present application provides a communication system, which may include the first network element and the second network element involved in the above embodiments.

[0392] An embodiment of the present application further provides a computer-readable storage medium, which is used to store a computer program or instruction. When the computer program or instruction is executed by a computer, the computer can implement the communication method provided by the above method embodiment.

[0393] An embodiment of the present application further provides a computer program product, which is used to store a computer program or instructions. When the computer program or instructions are executed by a computer, the computer can implement the communication method provided by the above method embodiment.

[0394] An embodiment of the present application further provides a chip or chip system, including a logic circuit, wherein the logic circuit is used to execute the communication method provided by the above method embodiment.

[0395] An embodiment of the present application also provides a chip or chip system, including one or more processors, which are coupled to at least one memory and are used to call the program in the memory so that the chip or chip system implements the communication method provided by the above method embodiment.

[0396] An embodiment of the present application also provides a chip or a chip system, which is coupled to at least one memory and is used to implement the communication method provided by the above method embodiment.

[0397] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0398] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the present application. It should be understood that each flow and / or box in the flow chart and / or block diagram, as well as the combination of the flow chart and / or box in the flow chart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more flow charts and / or one or more boxes in the block diagram.

[0399] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0400] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0401] Obviously, those skilled in the art may make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include these modifications and variations.

Claims

1. A communication method, characterized in that: include: The second network element receives a first request from the first network element, where the first request is used to request whether the first terminal device and the second terminal device communicate with each other using a satellite transmission method; The first terminal device accesses a first satellite, and the second terminal device accesses a second satellite; The second network element sends a first indication message to the first network element according to the first request, wherein the first indication message is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method, or the first indication message is used to indicate that the first terminal device and the second terminal device do not communicate using a satellite transmission method.

2. The method according to claim 1, wherein The first request includes one or more of the following: identification information of the first satellite, identification information of the second satellite, information of the first terminal device, information of the second terminal device, or information requiring communication between the first terminal device and the second terminal device using satellite transmission.

3. The method according to claim 2, wherein The identification information of the first satellite is an identifier of a first user plane function network element, an identifier of a first access network device, an identifier of a first access gateway, or an identifier of the first satellite, and at least one of the first user plane function network element, the first access network device, and the first access gateway is located on the first satellite and provides services for the first terminal device; The identification information of the second satellite is an identifier of a second user plane function network element, an identifier of a second access network device, an identifier of a second access gateway, or an identifier of the second satellite. At least one of the second user plane function network element, the second access network device, and the second access gateway is located on the second satellite and provides services for the second terminal device.

4. The method according to claim 2 or 3, wherein: The information of the first terminal device includes one or more of the following: an identifier of the first terminal device, an Internet Protocol IP address of the first terminal device, location information of the first terminal device, a movement trajectory of the first terminal device, or identification information of the first satellite; The information of the second terminal device includes one or more of the following: an identifier of the second terminal device, an IP address of the second terminal device, location information of the second terminal device, a movement trajectory of the second terminal device, or identification information of the second satellite.

5. The method according to any one of claims 1 to 4, characterized in that The second network element sending first indication information to the first network element according to the first request includes: The second network element determines the first indication information according to the first request and a first principle, and sends the first indication information to the first network element.

6. The method according to claim 5, wherein The first principle includes one or more of the following: If the delay of communication between the first terminal device and the second terminal device using satellite transmission is less than the delay of communication between the first terminal device and the second terminal device using terrestrial transmission, the first terminal device and the second terminal device communicate with each other using satellite transmission; or If the number of path nodes for communication between the first terminal device and the second terminal device using satellite transmission is less than the number of path nodes for communication between the first terminal device and the second terminal device using terrestrial transmission, the first terminal device and the second terminal device communicate using satellite transmission; or If a time delay for communication between the first terminal device and the second terminal device using a satellite transmission mode is less than a time delay for communication between the first terminal device and the second terminal device using a terrestrial transmission mode, and the first satellite and the second satellite are moving in the same direction, and the time delay for communication between the first terminal device and the second terminal device using a satellite transmission mode is greater than or equal to the first time delay, then communication between the first terminal device and the second terminal device is performed using a satellite transmission mode; or The number of path nodes for communication between the first terminal device and the second terminal device using satellite transmission is less than the number of path nodes for communication between the first terminal device and the second terminal device using ground transmission, and the movement directions of the first satellite and the second satellite are consistent, and the number of path nodes for communication between the first terminal device and the second terminal device using satellite transmission is less than or equal to a first node number threshold, then the first terminal device and the second terminal device communicate using satellite transmission.

7. The method according to any one of claims 1 to 6, wherein: The method further comprises: The second network element sends information of a first transmission path to the first network element, where the first transmission path is used for communication between the first terminal device and the second terminal device using a satellite transmission method.

8. The method according to claim 7, wherein When the transmission delay between the first user plane function network element and the second user plane function network element is greater than the transmission delay between the third user plane function network element and the fourth user plane function network element, determining the first transmission path; wherein the first user plane function network element is located on the first satellite, the second user plane function network element is located on the second satellite, the third user plane function network element is located on the third satellite, and the fourth user plane function network element is located on the fourth satellite; or When the transmission delay between the first user plane function network element, the first access gateway, the second access gateway, and the second user plane function network element is greater than the transmission delay between the third user plane function network element, the third access gateway, the fourth access gateway, and the fourth user plane function network element, determining the first transmission path; wherein the first user plane function network element and the first access gateway are located on the first satellite, the second user plane function network element and the second access gateway are located on the second satellite, the third user plane function network element and the third access gateway are located on the third satellite, and the fourth user plane function network element and the fourth access gateway are located on the fourth satellite.

9. The method according to claim 7 or 8, wherein The information of the first transmission path includes: an identifier of a third user plane function network element and an identifier of a fourth user plane function network element; wherein the third user plane function network element is located on a third satellite, and the fourth user plane function network element is located on a fourth satellite; Alternatively, the information of the first transmission path includes: an identifier of the third user plane function network element and an identifier of the fourth user plane function network element, as well as an identifier of a third access gateway and an identifier of a fourth access gateway; wherein the third user plane function network element and the third access gateway are located on the third satellite, and the fourth user plane function network element and the fourth access gateway are located on the fourth satellite.

10. A communication method, characterized in that: include: The first network element sends a first request to the second network element, where the first request is used to request whether the first terminal device and the second terminal device communicate with each other using a satellite transmission method; The first terminal device accesses a first satellite, and the second terminal device accesses a second satellite; The first network element receives first indication information from the second network element, and the first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, or the first indication information is used to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission.

11. The method according to claim 10, wherein The first network element is a session management function network element, and the method further includes: When the first indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method, the first network element sends the flow rules of the first terminal device and the second terminal device to the first user plane function network element and the second user plane function network element; the first user plane function network element is located on the first satellite, and the second user plane function network element is located on the second satellite; and / or When the first indication information is used to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission, the first network element sends the flow rules of the first terminal device and the second terminal device to the user plane function network element located on the ground.

12. The method according to claim 10 or 11, wherein: The first network element is a session management function network element, and the method further includes: When the first indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method, the first network element sends second indication information to the proxy call session control function network element through the policy control function network element, and the second indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method.

13. The method according to any one of claims 10 to 12, wherein: The first network element is a session management function network element, and the method further includes: When the first indication information is used to indicate that the first terminal device and the second terminal device communicate with each other using satellite transmission, the first network element establishes a tunnel between the first satellite and the second satellite.

14. The method according to any one of claims 10 to 12, wherein: When the first network element is a session management function network element, and the first indication information is used to indicate that the first terminal device and the second terminal device communicate using a satellite transmission method, the method further includes: The first network element sends the flow rules between the first terminal device and the second terminal device to the first access gateway and the second access gateway.

15. The method according to claim 14, wherein The method further comprises: The first network element receives the identifier of the first access gateway and the identifier of the second access gateway from a proxy call session control function network element or a policy control function network element; The first network element sending a flow rule between the first terminal device and the second terminal device to the first access gateway and the second access gateway includes: The first network element sends, to the first access gateway according to the identifier of the first access gateway, a flow rule between the first terminal device and the second terminal device; The first network element sends the flow rules between the first terminal device and the second terminal device to the second access gateway according to the identifier of the second access gateway.

16. The method according to claim 10, wherein The method further comprises: The first network element receives information of a first transmission path from the second network element, where the first transmission path is used for communication between the first terminal device and the second terminal device using a satellite transmission method.

17. The method according to claim 16, wherein The first network element is a session management function network element, and the information of the first transmission path includes an identifier of a third user plane function network element and an identifier of a fourth user plane function network element, wherein the third user plane function network element is located on a third satellite, and the fourth user plane function network element is located on a fourth satellite. The method further includes: When the first indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, the first network element establishes a tunnel between the third satellite and the fourth satellite according to the information of the first transmission path.

18. The method according to claim 16, wherein The first network element is a session management function network element, and the information of the first transmission path includes: an identifier of a third user plane function network element, an identifier of a fourth user plane function network element, and an identifier of a third access gateway, and an identifier of a fourth access gateway; wherein the third user plane function network element and the third access gateway are located on the third satellite, and the fourth user plane function network element and the fourth access gateway are located on the fourth satellite. The method further includes: When the first indication information is used to indicate that the first terminal device and the second terminal device communicate with each other by satellite transmission, the first network element requests the proxy call session control function network element to adopt the first transmission path according to the information of the first transmission path; The first network element determines whether to adopt the first transmission path according to a response of the proxy call session control function network element to the request.

19. The method according to claim 18, wherein The first network element requests a proxy call session control function network element to adopt the first transmission path according to information about the first transmission path, including: The first network element sends the identifier of the third access gateway and the identifier of the fourth access gateway to the proxy call session control function network element; The first network element determines whether to adopt the first transmission path according to a response of the proxy call session control function network element to the request, including: If the first network element receives the identifier of the third access gateway and the identifier of the fourth access gateway from the proxy call session control function network element, the first network element determines to use the first transmission path; and / or, If the first network element receives access gateway identifiers other than the identifier of the third access gateway and the identifier of the fourth access gateway from the proxy call session control function network element, the first network element determines not to use the first transmission path.

20. The method according to claim 19, wherein When the first network element determines not to use the first transmission path, the method further includes: The first network element sends a second request to the second network element, where the second request is used to request whether the first terminal device and the second terminal device communicate with each other using a satellite transmission method; The first network element receives third indication information from the second network element, and the third indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, or the third indication information is used to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission.

21. The method according to claim 16, wherein The first network element is a proxy call session control function network element, and the information of the first transmission path includes an identifier of a third user plane function network element, an identifier of a fourth user plane function network element, and an identifier of a third access gateway and an identifier of a fourth access gateway, wherein the third user plane function network element and the third access gateway are located on a third satellite, and the fourth user plane function network element and the fourth access gateway are located on a fourth satellite; when the first indication information is used to indicate that communication between the first terminal device and the second terminal device is performed using a satellite transmission manner, the method further includes: When the loads of the third access gateway and the fourth access gateway are both less than or equal to a first load threshold, the first network element sends the identifier of the third access gateway and the identifier of the fourth access gateway and the first indication information to the session management function network element; or When the load of at least one of the third access gateway and the fourth access gateway is greater than the first load threshold, the first network element sends a third request to the second network element, and the third request is used to request whether the first terminal device and the second terminal device communicate using satellite transmission.

22. The method according to claim 10, wherein The first network element is a proxy call session control function network element or a policy control function network element, and the method further includes: The first network element sends the first indication information to the session management function network element.

23. The method according to any one of claims 10 to 22, wherein: When satellite switching occurs in the first terminal device and / or the second terminal device, the method further includes: The first network element sends a fourth request to the second network element, where the fourth request is used to request whether the first terminal device and the second terminal device communicate with each other using a satellite transmission method; The first network element receives fourth indication information from the second network element, and the fourth indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, or to indicate that the first terminal device and the second terminal device do not communicate using satellite transmission.

24. The method according to claim 23, wherein The first network element is a session management function network element, and the method further includes: When the fourth indication information is used to indicate that the first terminal device and the second terminal device communicate using satellite transmission, and an access gateway is deployed on the target satellite of the terminal device where satellite switching occurs, the first network element sends a switching indication to the proxy call session control function network element, and the switching indication is used to indicate the path switching between the first terminal device and the second terminal device.

25. A communication method, characterized in that: include: Determining a first target access gateway and a second target access gateway, where the first target access gateway and the second target access gateway are used for communication between the first terminal device and the second terminal device using a satellite transmission manner; The first terminal device accesses a first satellite, and the second terminal device accesses a second satellite; Sending the identifier of the first target access gateway and the identifier of the second target access gateway to a session management function network element.

26. The method of claim 25, wherein: The determining of the first target access gateway and the second target access gateway includes: Determine the first target access gateway and the second target access gateway based on ephemeris information and information of the first terminal device and the second terminal device; or obtain the identifier of the first target access gateway and the identifier of the second target access gateway from an evaluation network element.

27. The method of claim 25, wherein: The method further comprises: receiving second indication information from the session management function network element, where the second indication information is used to instruct the first terminal device and the second terminal device to communicate using a satellite transmission method; The determining of the first target access gateway and the second target access gateway includes: If the loads of the first access gateway and the second access gateway are both less than or equal to the first load threshold, the first target access gateway is determined to be the first access gateway and the second target access gateway is determined to be the second access gateway according to the second indication information; wherein the first access gateway is located at the first satellite and the second access gateway is located at the second satellite.

28. The method of claim 25, wherein: The method further comprises: receiving an identifier of a third access gateway and an identifier of a fourth access gateway from the session management function network element, where the third access gateway is located on a third satellite and the fourth access gateway is located on a fourth satellite; The determining of the first target access gateway and the second target access gateway includes: If the loads of the third access gateway and the fourth access gateway are both less than or equal to a first load threshold, the first target access gateway is determined to be the third access gateway, and the second target access gateway is determined to be the fourth access gateway.

29. The method according to any one of claims 25 to 28, wherein: The method further comprises: receiving a switching instruction from the session management function network element, where the switching instruction is used to instruct a path switch between the first terminal device and the second terminal device; According to the switching indication, first information is sent to the first terminal device or the second terminal device, where the first information is used to initiate a voice call process.

30. A communication device, characterized in that: The method comprises a unit or module for executing the method according to any one of claims 1 to 9, or a unit or module for executing the method according to any one of claims 10 to 24, or a unit or module for executing the method according to any one of claims 25 to 29.

31. A communication device, characterized in that: The method comprises a processor configured to execute a computer program or instructions to implement the method according to any one of claims 1 to 9, or the method according to any one of claims 10 to 24, or the method according to any one of claims 25 to 29.

32. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program or instruction. When the computer program or instruction is executed by the communication device, the method according to any one of claims 1 to 9 is implemented, the method according to any one of claims 10 to 24 is implemented, and the method according to any one of claims 25 to 29 is implemented.

33. A computer program product, characterized in that The computer program product comprises a computer program or instructions, which, when executed by a computer, enables the method according to any one of claims 1 to 9, the method according to any one of claims 10 to 24, or the method according to any one of claims 25 to 29 to be implemented.

34. A chip or a chip system, characterized in that: The chip or chip system includes a logic circuit, which is used to execute the method as described in any one of claims 1 to 9, or to execute the method as described in any one of claims 10 to 24, or to execute the method as described in any one of claims 25 to 29.

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