Communication method and apparatus

Abstract

A communication method and apparatus, which belong to the technical field of communications. When there is no connection between a first satellite where a first application server is located and a satellite (i.e., a second satellite) accessed by a first terminal, a first network element can determine a second application server deployed on the ground, such that the first terminal can fall back to accessing the application server on the ground, thereby enabling the first terminal to access a service. Alternatively, the first network element can determine a third satellite connected to the first satellite, such that the first terminal can access the third satellite and access the first application server on board by means of the third satellite, thereby enabling the first terminal to access a service.

Description

Communication methods and devices

[0001] This application claims priority to Chinese Patent Application No. 202411554677.X, filed on October 31, 2024, entitled "Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and more specifically, to a communication method and apparatus. Background Technology

[0003] In non-terrestrial network (NTN) scenarios, aircraft (e.g., airplanes or drones) or satellites are incorporated into the communication system. Terminals can access services deployed on NTN devices or the ground via satellites or other NTN equipment. Because satellites are constantly moving, their coverage areas and inter-satellite links are constantly changing, resulting in a continuous shift in the satellites used to provide services to terminal devices.

[0004] Therefore, in NTN scenarios, how to enable terminals to access services is an urgent problem to be solved. Summary of the Invention

[0005] This application provides a communication method and apparatus that enables terminals to access services in NTN scenarios.

[0006] Firstly, a communication method is provided. The implementing entity of the method provided in the first aspect can be a first network element. Unless otherwise specified, the first network element in this application can be the device itself capable of implementing session management functions, a component within that device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the session management functions. For ease of description, the following description uses a first network element as an example.

[0007] For example, the first network element can be used for session management and / or connection management. For instance, the first network element can be called a session management function (SMF) or other names; this application does not limit the specific name of the first network element. The first network element can be a network element (or a function within a network element) used for session management and / or connection management in a 5G communication system or a future communication system.

[0008] The method includes: receiving first information from a second network element, wherein the first information is used to indicate a first application server, the first application server being deployed on a first satellite, the first application server being used to provide a first service to a first terminal, a second satellite being used to provide access services to the first terminal, and there is no connection between the first satellite and the second satellite; sending second information, wherein the second information is used to determine a second application server, the second application server being deployed on the ground, the second application server being used to provide the first service to the first terminal; or, the second information is used to determine a third satellite, the third satellite being used to replace the second satellite in providing access services to the first terminal, and there is a connection between the third satellite and the first satellite.

[0009] Unless otherwise specified, the first terminal in this application can be the terminal device itself, a component within the terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the terminal device's functions. For ease of description, the following description uses the first terminal as an example.

[0010] Unless otherwise specified, the second network element in this application can be the device itself capable of discovering or selecting EAS, a component within that device (e.g., a processor, chip, or chip system), or a logical module or software capable of implementing all or part of the EAS discovery function. Examples include edge application server discovery function (EASDF), user plane function (UPF), domain name system (DNS) server, or other devices capable of collaboratively or independently performing EAS discovery; no limitation is made. For ease of description, the second network element will be used as an example below.

[0011] The phrase "the first information is used to indicate the first application server" can also be understood as: the SMF can determine the first application server based on the first information, or the first information is information about the first application server, or the first information corresponds to the first application server.

[0012] For example, the first information may include the identifier of the first application server, address information, or other information capable of identifying the first application server. For example, the identifier of the first application server may include: an identifier field, a domain name pointing to the first application server, etc., which are not limited in this application. For example, the address information may include: an IP address (e.g., an IPv4 address or an IPv6 address), a MAC address, or other information capable of indicating an address, which are not limited in this application.

[0013] For example, the first information can be carried in a DNS context notification message, such as a Neasdf_DNSContext_Notify message. The first information can also be carried in other messages, which are not limited in this application.

[0014] The first application server can be a server device, a component within the server device, a virtual machine, an instance, a container, or a logical module or software that provides all or part of the application service functions. For example, the first application server can be an Edge Application Server (EAS).

[0015] The first application server can be used to provide a first service to the first terminal; or it can be understood as the first application server being used to provide the first service to the first terminal; or it can be understood as the first terminal being able to obtain the first service by accessing the first application server; or it can be understood as the first application server being used to enable the first terminal to access the first service; or it can be understood as the first application server being used for the first terminal to access the first service; or it can be understood as the first terminal being able to access the first application server to receive the first service; or it can be understood as the first terminal being able to access the first service through the first application server; or it can be understood as the first service being deployed / configured on the first application server; or it can be understood as the first terminal accessing (or accessing) the first service through the first application server; or it can be understood as the first application server being used for the first terminal to access (or access) the first service.

[0016] It is understandable that the fact that the first application server can be used to provide the first service to the first terminal does not mean that the first application server will necessarily successfully provide the first service to the first terminal. In other words, the first terminal may not be able to successfully access the first application server, or access the first service through the first application server. For example, the first application server may not be able to communicate with the satellite currently connected to the first terminal (for example, there may be no inter-satellite link between the satellite deployed by the first application server and the satellite connected to the first terminal during a certain period of time), thus failing to provide the first service to the first terminal. However, those skilled in the art will understand that the first application server has the capability to provide the first service to the first terminal, but may not necessarily successfully provide the first service.

[0017] This application does not limit the type of the first service. For example, the first service can be any service type defined in 3GPP standards (e.g., those defined in 3GPP TS23.401 and 23.501, or those defined by protocols of future communication technologies), such as Short Message Service (SMS), IP Multimedia Subsystem (IMS), or any data network name (DNN) and / or network slice. For example, the first service can also be any service type understood by those skilled in the art, such as voice call service, video playback service, audio playback service, video conferencing service, online game service, electronic transaction service, or other data transmission-related services; this application does not specifically limit this.

[0018] For example, the second satellite provides access services to the first terminal, which may be that the first terminal accesses the second satellite, or the first terminal accesses an access network device deployed on the second satellite, or the access network device deployed on the second satellite is used to provide access services to the first terminal, or the first terminal accesses the network through the second satellite, or the second satellite is the satellite that the first terminal accesses.

[0019] For example, there is no connection between the first satellite and the second satellite, which could mean that there is no inter-satellite link between the first satellite and the second satellite.

[0020] The second application server can be a server device, a component within the server device, a virtual machine, an instance, a container, or a logical module or software that can provide all or part of the application service functions. For example, the second application server can be an AS (Application Server) or other server.

[0021] The second application server can be deployed on the ground. The second satellite can connect to the ground, for example, directly to a ground-based gateway station, which in turn connects to the second application server via IP. Alternatively, the second satellite can connect to other satellites via inter-satellite links, and these other satellites can then directly connect to the ground-based gateway station, which in turn connects to the second application server via IP. In this way, the first terminal can access the second application server through the second satellite.

[0022] The second application server can be used to provide the same services to the first terminal as the first application server. For example, the second application server can be used to provide the first terminal with services that correspond to the same fully qualified domain name (FQDN) as the first application server.

[0023] For example, the second application server can be used to provide a first service to the first terminal; or it can be understood that the second application server can be used to provide the service of the first service to the first terminal; or it can be understood that the first terminal can obtain the service of the first service by accessing the second application server; or it can be understood that the second application server can be used to enable the first terminal to access the first service; or it can be understood that the second application server can be used for the first terminal to access the first service; or it can be understood that the first terminal can access the second application server to receive the first service; or it can be understood that the first terminal can access the first service through the second application server; or it can be understood that the first service is deployed / configured on the second application server; or it can be understood that the first terminal accesses (or accesses) the first service through the second application server; or it can be understood that the second application server is used for the first terminal to access (or access) the first service.

[0024] Alternatively, the above scheme can be understood as follows: the second application server can be used to provide the first service to the first terminal via the second satellite; or the second application server can be used to provide the first service to the first terminal via the second satellite; or the second application server can be used to enable the first terminal to access the first service via the second satellite; or the second application server can be used for the first terminal to access the first service via the second satellite; or the first terminal can access the second application server via the second satellite to receive the first service; or the first terminal can access the first service via the second application server and the second satellite.

[0025] Alternatively, the above scheme can be understood as follows: the second application server can be used to provide the first service to the first terminal through the access network equipment on the second satellite; or it can be understood as the second application server can be used to provide the first service to the first terminal through the access network equipment on the second satellite; or it can be understood as the second application server can be used to enable the first terminal to access the first service through the access network equipment on the second satellite; or it can be understood as the first terminal can access the second application server through the access network equipment on the second satellite to receive the first service; or it can be understood as the first terminal can access the first service through the second application server and the access network equipment on the second satellite.

[0026] The third satellite may be equipped with access network equipment. This access network equipment can be the target access network equipment for the first terminal. The first terminal can be redirected to the target access network equipment.

[0027] There can be a connection between the third satellite and the first satellite. In other words, the third satellite and the first satellite can communicate with each other (for example, there is an inter-satellite link between the third satellite and the first satellite, or the third satellite and the first satellite are the same satellite, that is, the target access network device of the first terminal and the first application server are deployed on the same satellite). In this way, the access network device on the third satellite can communicate with the first application server on the first satellite.

[0028] The third satellite can be used to replace the second satellite in providing access services to the first terminal; in other words, the third satellite can be the satellite that provides access services to the first terminal after the first terminal is redirected; in other words, the third satellite can be the satellite deployed by the access network equipment serving the first terminal after the first terminal is redirected; in other words, the third satellite can be the satellite that provides access services to the first terminal after the first terminal is switched; in other words, the third satellite can be the satellite deployed by the access network equipment serving the first terminal after the first terminal is switched; in other words, the third satellite can be the satellite deployed by the target access network equipment of the first terminal.

[0029] Based on the above scheme, if there is no connection between the first satellite where the first application server is located and the satellite accessed by the first terminal (i.e., the second satellite), the first network element can determine the second application server deployed on the ground, thereby enabling the first terminal to fall back to access the application server on the ground and access the service. Alternatively, the first network element can determine the third satellite connected to the first satellite, thereby enabling the first terminal to access the third satellite and access the first application server on the satellite, thus enabling the first terminal to access the service.

[0030] In some implementations, sending the second information includes sending the second information to the second network element, the second information including first address information used to determine the second application server deployed on the ground.

[0031] In some implementations, the first address information is the address information of a network element deployed on the ground.

[0032] In some implementations, the method also includes obtaining the address of the second application server.

[0033] In some implementations, the method further includes sending information A, which instructs the second network element to send a Domain Name System (DNS) response message to the first terminal. The DNS response message may include the address of the second application server.

[0034] In some implementations, the method further includes: sending third information to the second network element, the third information being used to instruct the second network element not to send information about the server deployed on the ground to the first network element, and / or, the third information being used to instruct the second network element not to send information about the first service to the first network element.

[0035] Based on the above scheme, the edge application server discovery function (EASDF) can avoid sending traffic splitting point configuration information to the SMF, saving transmission overhead. Furthermore, the SMF does not need to configure traffic splitting points. On the one hand, this avoids the signaling overhead associated with configuring traffic splitting points; on the other hand, the first terminal accesses the second application server through the anchor user plane network element, without needing to go through additional user plane network elements, thereby reducing the latency of the first terminal accessing the second application server in NTN scenarios.

[0036] In some implementations, the method further includes: configuring the first terminal to access the second application server through an anchor user plane network element.

[0037] Among them, the anchor point user plane network element can be deployed on the ground or connected to the ground.

[0038] In this context, the anchor user plane network element can be referred to as a Protocol Data Unit (PDU) session anchor (PSA), PSA UPF, central-PSA (C-PSA), or C-PSA UPF. In other words, the SMF may not configure a split-point UPF (e.g., an uplink classifier (UL-CL or ULCL)) and / or a branching point (BP) and / or a local PDU session anchor (L-PSA). Alternatively, the SMF may not perform the actions of selecting and / or configuring the split-point UPF and / or L-PSA.

[0039] In this way, the first terminal can access the second application server deployed on the ground through only one anchor user plane network element (e.g., PSA) configured by the SMF, without going through other UPFs.

[0040] Based on the above scheme, SMF can configure the first terminal to access the second application server through the anchor user plane network element without going through an additional user plane network element, thereby reducing the latency of the first terminal accessing the second application server in the NTN scenario.

[0041] In some implementations, sending the second information includes sending the second information to a third network element, the second information including information about the first satellite, the information about the first satellite being used to determine the third satellite with which there is a connection.

[0042] The third network element can be used to provide the first network element with one or more of the following: the location information of the first terminal, the access type, and the accessed satellites. Its name is not limited. The third network element can be the device itself capable of performing the above functions, a component within that device (e.g., a processor, chip, or chip system), or a logic module or software capable of performing all or part of the above functions.

[0043] For example, a third network element can be the device itself capable of implementing access and / or mobility management functions, a component within that device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the access and / or mobility management functions. For ease of description, the following description uses a third network element as an example.

[0044] In some implementations, the second information also includes first indication information, which is used to indicate that the first terminal should be redirected.

[0045] In some implementations, the method further includes receiving fourth information from a fourth network element, the fourth information indicating that there is no connection between the first satellite and the second satellite.

[0046] Based on the above scheme, the SMF can determine that there is no connection between the first satellite and the second satellite based on indications from other network elements. In this scheme, the processing overhead of the SMF in determining that there is no connection between the first and second satellites is relatively small. For example, compared to the SMF's calculation based on ephemeris information, the above scheme only needs to identify the indication of the fourth information, resulting in lower processing overhead.

[0047] In some implementations, the method further includes sending fifth information to a fourth network element, the fifth information being used to query whether there is a connection between the first satellite and the second satellite.

[0048] Based on the above scheme, SMF can send information to the fourth network element to query whether there is a connection between the first satellite and the second satellite, thereby reducing the processing overhead caused by the absence of a connection between the first satellite and the second satellite.

[0049] In some implementations, the fifth information includes at least one of the information of the first application server, the information of the first satellite, or the information of the second satellite.

[0050] In some implementations, the fifth information includes information about the first satellite and / or the second satellite. Before sending the fifth information to the fourth network element, the method further includes receiving information about the first satellite from the fifth network element.

[0051] In some implementations, before sending the fifth information to the fourth network element, the method further includes sending information B to the fifth network element, which is used to query the information of the first satellite.

[0052] In some implementations, information B includes information about the first application server.

[0053] In some implementations, the method further includes: obtaining ephemeris information; and determining, based on the ephemeris information, that there is no connection between the first satellite and the second satellite.

[0054] In some implementations, before receiving the first information from the second network element, the method further includes sending second address information to the second network element, the second address information being used to determine the first application server deployed on the satellite.

[0055] For example, the second address information could be the address information of a network element (e.g., a UPF) deployed on the satellite.

[0056] Based on the above scheme, SMF can send a second address information to EASDF to help discover application servers deployed on satellites.

[0057] In some implementations, the method further includes: obtaining information about the first service; wherein sending the second address information to the second network element includes: sending the second address information to the second network element when the server corresponding to the first service is deployed on a satellite.

[0058] Based on the above scheme, SMF can use the second address information to help discover the application server deployed on the satellite when the server corresponding to the first service is deployed on the satellite, thus avoiding the discovery of the application server deployed on the satellite when there is no service deployed on the satellite, thereby enhancing the availability of UE#1 accessing the service.

[0059] Secondly, a communication method is provided. The implementing entity of the method provided in this application can be a third network element. Unless otherwise specified, the third network element in this application can be the device itself capable of providing access management functions, a component within that device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the access management functions. For ease of description, the following description uses a third network element as an example.

[0060] For example, the third network element can be an access management network element.

[0061] The method includes: receiving second information from a first network element, the second information being used to identify a third satellite; sending sixth information to a second satellite, the second satellite being used to access a first terminal, the sixth information being used to instruct the first terminal to be redirected to the third satellite, the third satellite being connected to the first satellite, the first satellite being deployed with a first application server, the first application server being used to provide a first service to the first terminal.

[0062] In some implementations, the method further includes: determining the third satellite based on the second information, wherein the third satellite is connected to the first satellite and the third satellite is equipped with access network equipment.

[0063] In some implementations, the method further includes: acquiring ephemeris information; wherein determining the third satellite based on the second information includes: determining the third satellite based on the second information and the ephemeris information.

[0064] The beneficial effects of the second aspect and any implementation thereof can be found in the first aspect and any implementation thereof, and will not be repeated here.

[0065] Thirdly, a communication method is provided. The implementing entity of the method provided in this application can be a first network element. Unless otherwise specified, the first network element in this application can be the device itself capable of implementing session management functions, a component within that device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the session management functions. For ease of description, the following description uses the first network element as an example.

[0066] For example, the first network element can be used for session management and / or connection management. For instance, the first network element can be called a session management function (SMF) or other names; this application does not limit the specific name of the first network element. The first network element can be a network element (or a function within a network element) used for session management and / or connection management in a 5G communication system or a future communication system.

[0067] The method includes: receiving seventh information, wherein the seventh information is used to indicate information of a second service; and, in the case that the second service is deployed on a satellite, sending information of a first DNS server to a second network element, wherein the first DNS server is used to determine a third application server that has a connection with a fourth satellite, the third application server is used to provide the second service to the second terminal, and the fourth satellite is used to provide access service to the second terminal.

[0068] Unless otherwise specified, the second terminal in this application can be the terminal device itself, a component within the terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the terminal device's functions. For ease of description, the following description uses the second terminal as an example.

[0069] Unless otherwise specified, the second network element in this application can be the device itself capable of discovering or selecting EAS, a component within that device (e.g., a processor, chip, or chip system), or a logical module or software capable of implementing all or part of the EAS discovery function. Examples include EASDF, UPF, DNS servers, or other devices capable of collaboratively or independently performing EAS discovery; no limitation is made. For ease of description, the following description uses the second network element as an example.

[0070] For example, the seventh piece of information can be carried in a DNS context notification message, such as a Neasdf_DNSContext_Notify message. The seventh piece of information can also be carried in other messages, which are not limited herein.

[0071] Unless otherwise specified, the first DNS server (also referred to as the first DNS resolver) in this application can be a server device, a component within a server device (e.g., a processor, chip, or chip system), a virtual machine, a container, or an instance, or a logical module or software capable of providing all or part of the DNS service functions. For ease of description, the following description uses the first DNS server as an example.

[0072] The fourth satellite provides access services to the second terminal, which can be that the second terminal accesses the fourth satellite, or the second terminal accesses the access network equipment deployed on the fourth satellite, or the access network equipment deployed on the fourth satellite is used to provide access services to the second terminal, or the second terminal accesses the network through the fourth satellite, or the fourth satellite is the satellite that the second terminal accesses.

[0073] Specifically, the third application server can be used to provide a second service to the second terminal; or it can be understood as the third application server being used to provide the second service to the second terminal; or it can be understood as the second terminal being able to obtain the second service by accessing the third application server; or it can be understood as the third application server being used to enable the second terminal to access the second service; or it can be understood as the third application server being used for the second terminal to access the second service; or it can be understood as the second terminal being able to access the third application server to receive the second service; or it can be understood as the second terminal being able to access the second service through the third application server; or it can be understood as the second service being deployed / configured on the third application server; or it can be understood as the second terminal accessing (or accessing) the second service through the third application server; or it can be understood as the third application server being used for the second terminal to access (or access) the second service.

[0074] It is understandable that while a third application server can be used to provide a second service to a second terminal, this does not mean that the third application server will necessarily successfully provide the second service to the second terminal. In other words, the second terminal may not be able to successfully access the third application server, or access the second service through the third application server. For example, the third application server may not be able to communicate with the satellite currently connected to the second terminal (e.g., there is no inter-satellite link between the satellite deployed by the third application server and the satellite connected to the second terminal during a certain period), thus failing to provide the second service to the second terminal. However, those skilled in the art will understand that the third application server has the capability to provide the second service to the second terminal, but may not necessarily successfully provide the second service.

[0075] For example, the information of the first DNS server may be address information, identification information, or other information corresponding to the first DNS server.

[0076] The aforementioned first DNS server may also be referred to as a specific DNS server, a local DNS server, a server, or other names, which are not limited in this application.

[0077] Based on the above scheme, SMF can provide information about a first DNS server. This first DNS server can be used to determine the application server that has a connection with the satellite accessed by the terminal, thereby enabling the first terminal to access services.

[0078] In some implementations, the third application server is deployed on the fifth satellite, which is connected to the fourth satellite.

[0079] In some implementations, the method further includes: sending third address information to the second network element, the third address information being used to indicate the fourth satellite, or the third address information being used to indicate a satellite connected to the fourth satellite.

[0080] In some implementations, the first DNS server is used to determine, based on the third address information, the third application server that has a connection with the fourth satellite.

[0081] In some implementations, the third address information is the address information of the fourth network element, which is deployed on the fourth satellite, or the satellite on which the fourth network element is deployed is connected to the fourth satellite.

[0082] In some implementations, the method further includes: obtaining eighth information, the eighth information being used to indicate at least one service deployed on the satellite; and determining, based on the eighth information, that the second service is deployed on the satellite and that the second service belongs to the at least one service.

[0083] In some implementations, the method further includes: obtaining ninth information, the ninth information including a correspondence between at least one network access point and at least one DNS server, and / or a correspondence between at least one service and at least one DNS server, wherein the second terminal corresponds to the first network access point among the at least one network access point; determining the first DNS server based on the ninth information, wherein the first DNS server corresponds to the first network access point, and / or the first DNS server corresponds to the second service.

[0084] Based on the above scheme, the SMF can select a DNS server according to the mapping between services and DNS servers, and / or the mapping between network access points and DNS servers. This first DNS server can be a specific DNS server corresponding to the network access point of the first service and / or the first terminal, thereby enabling better discovery of application servers for the first terminal. For example, compared to all services and / or network access points sharing a single DNS server, the above scheme can provide application server discovery services for the remaining services and / or network access points even if some DNS servers fail. Furthermore, the first DNS server can discover application servers connected to the satellite accessed by the first terminal without requiring address information (e.g., third-party address information).

[0085] In some implementations, the method further includes: when the second terminal does not access the network via satellite, and / or when the second service is not deployed via satellite, sending fourth address information to the second network element, the fourth address information being used to determine a fourth application server deployed on the ground, the fourth application server being used to provide the second service to the second terminal.

[0086] Fourthly, a communication method is provided. The executing entity of the method provided in this fourth aspect can be a first DNS server (also referred to as a first DNS resolver). Unless otherwise specified, the first DNS server in this application can be the server device itself, or a component within the server device (e.g., a processor, chip, or chip system), virtual machine, container, or instance, or it can be a logical module or software capable of implementing all or part of the functions of the server device. For ease of description, the following description uses a first DNS server as an example.

[0087] The method includes: receiving a query message, the query message including third address information and second service information; determining a third application server based on the third address information and the second service information, the third application server having a connection with a fourth satellite, the third application server being used to provide the second service to a second terminal, the fourth satellite being used to provide access service to the second terminal, the third address information being used to indicate the fourth satellite, or the third address information being used to indicate a satellite having a connection with the fourth satellite.

[0088] In some implementations, determining the third application server based on the third address information and the second service information includes: determining the third application server based on the third address information, the second service information, and ephemeris information.

[0089] In some implementations, the third address information is the address information of the fourth network element, which is deployed on the fourth satellite, or the satellite on which the fourth network element is deployed is connected to the fourth satellite.

[0090] In some implementations, the method further includes sending a response message to the query message, the response message including the address of the third application server.

[0091] The beneficial effects of the fourth aspect and any implementation thereof can be found in the third aspect and any implementation thereof, and will not be repeated here.

[0092] Fifthly, a communication device is provided, including processing circuitry (or a processor) and an input / output interface (also referred to as an interface circuit), the input / output interface being used for inputting and / or outputting signals, the processing circuitry being used to perform the first aspect and any possible method of the first aspect, or the processing circuitry being used to perform the second aspect and any possible method of the second aspect, or the processing circuitry being used to perform the third aspect and any possible method of the third aspect, or the processing circuitry being used to perform the fourth aspect and any possible method of the fourth aspect.

[0093] In some implementations, the processing circuit is used to communicate with other devices through the interface circuit and to perform the first aspect and any possible method of the first aspect, or to perform the second aspect and any possible method of the second aspect, or to perform the third aspect and any possible method of the third aspect, or to perform the fourth aspect and any possible method of the fourth aspect.

[0094] Sixthly, a communication device is provided. This communication device may include units, modules, or means for performing the functions of the communication device.

[0095] In some implementations, the communication device may include modules, units, or means for performing the methods / operations / steps / actions described in the first aspect and any possible implementation of the first aspect. These modules, units, or means may be hardware circuits, software, or a combination of hardware circuits and software.

[0096] In some implementations, the communication device includes a transceiver unit. The transceiver unit is used to receive first information from a second network element, wherein the first information indicates a first application server deployed on a first satellite, the first application server providing a first service to a first terminal, and a second satellite providing access service to the first terminal; there is no connection between the first satellite and the second satellite. The transceiver unit is also used to send second information, wherein the second information identifies a second application server deployed on the ground, the second application server providing the first service to the first terminal; or, the second information identifies a third satellite, the third satellite providing access service to the first terminal in place of the second satellite, and there is a connection between the third satellite and the first satellite.

[0097] In some implementations, the transceiver unit is specifically used to send the second information to the second network element. The second information includes first address information, which is used to determine the second application server deployed on the ground.

[0098] In some implementations, the first address information is the address information of a network element deployed on the ground.

[0099] In some implementations, the transceiver unit is also used to obtain the address of the second application server.

[0100] In some implementations, the transceiver unit is also used to: send information A, which instructs the second network element to send a Domain Name System (DNS) response message to the first terminal. The DNS response message may include the address of the second application server.

[0101] In some implementations, the transceiver unit is further configured to: send third information to the second network element, the third information being used to instruct the second network element not to send information about the server deployed on the ground to the first network element, and / or, the third information being used to instruct the second network element not to send information about the first service to the first network element.

[0102] In some implementations, the device further includes a processing unit. This processing unit is used to configure the first terminal to access the second application server via an anchor user plane network element.

[0103] In some implementations, the transceiver unit is specifically used to: send the second information to a third network element, the second information including information about the first satellite, the information about the first satellite being used to determine the third satellite with which there is a connection.

[0104] In some implementations, the second information also includes first indication information, which is used to indicate that the first terminal should be redirected.

[0105] In some implementations, the transceiver unit is also used to: receive fourth information from a fourth network element, the fourth information being used to indicate that there is no connection between the first satellite and the second satellite.

[0106] In some implementations, the transceiver unit is also used to: send fifth information to the fourth network element, the fifth information being used to query whether there is a connection between the first satellite and the second satellite.

[0107] In some implementations, the fifth information includes at least one of the information of the first application server, the information of the first satellite, or the information of the second satellite.

[0108] In some implementations, the fifth information includes information about the first satellite and / or the second satellite, and the transceiver unit is further configured to: receive information about the first satellite from the fifth network element.

[0109] In some implementations, the transceiver unit is also used to send information B to the fifth network element, which is used to query information about the first satellite.

[0110] In some implementations, information B includes information about the first application server.

[0111] In some implementations, the processing unit is also used to: acquire ephemeris information; and determine, based on the ephemeris information, that there is no connection between the first satellite and the second satellite.

[0112] In some implementations, the transceiver unit is also used to: send second address information to the second network element, the second address information being used to determine the first application server deployed on the satellite.

[0113] In some implementations, the transceiver unit is also used to: acquire information about the first service. Specifically, if the server corresponding to the first service is deployed on a satellite, the transceiver unit is used to: send the second address information to the second network element.

[0114] In some implementations, the communication device may include modules, units, or means for performing the methods / operations / steps / actions described in the second aspect and any possible implementation of the second aspect, which may be hardware circuits, software, or a combination of hardware circuits and software.

[0115] In some implementations, the communication device includes a transceiver unit. The transceiver unit is used to receive second information from a first network element, the second information being used to identify a third satellite; the transceiver unit is also used to send sixth information to a second satellite, the second satellite being used to access a first terminal, the sixth information being used to instruct the first terminal to be redirected to the third satellite, the third satellite being connected to the first satellite, and the first satellite being deployed with a first application server, the first application server being used to provide a first service to the first terminal.

[0116] In some implementations, the device further includes a processing unit. This processing unit is used to: determine the third satellite based on the second information, wherein the third satellite has a connection with the first satellite and is equipped with access network equipment.

[0117] In some implementations, the processing unit is also used to: acquire ephemeris information. Specifically, the processing unit is used to: determine the third satellite based on the second information and the ephemeris information.

[0118] In some implementations, the communication device may include modules, units, or means for performing the methods / operations / steps / actions described in the third aspect and any possible implementation of the third aspect, which may be hardware circuits, software, or a combination of hardware circuits and software.

[0119] In some implementations, the communication device includes a transceiver unit. The transceiver unit is used to receive seventh information, wherein the seventh information is used to indicate information about a second service; and when the second terminal accesses the network via a satellite, and / or, where the second service is provided by a satellite, the transceiver unit is also used to send information about a first DNS server to a second network element. The first DNS server is used to determine a third application server that has a connection with a fourth satellite. The third application server is used to provide the second service to the second terminal, and the fourth satellite is used to provide access services to the second terminal.

[0120] In some implementations, the third application server is deployed on the fifth satellite, which is connected to the fourth satellite.

[0121] In some implementations, the transceiver unit is also used to: send third address information to the second network element, the third address information being used to indicate the fourth satellite, or the third address information being used to indicate a satellite connected to the fourth satellite.

[0122] In some implementations, the first DNS server is used to determine, based on the third address information, the third application server that has a connection with the fourth satellite.

[0123] In some implementations, the third address information is the address information of the fourth network element, which is deployed on the fourth satellite, or the satellite on which the fourth network element is deployed is connected to the fourth satellite.

[0124] In some implementations, the transceiver unit is further configured to: acquire eighth information, which indicates at least one service deployed on the satellite. The apparatus also includes a processing unit configured to determine, based on the eighth information, that the second service is deployed on the satellite and that the second service belongs to the at least one service.

[0125] In some implementations, the transceiver unit is further configured to: obtain ninth information, the ninth information including a correspondence between at least one network access point and at least one DNS server, and / or a correspondence between at least one service and at least one DNS server, wherein the second terminal corresponds to the first network access point among the at least one network access point; the processing unit is further configured to determine the first DNS server based on the ninth information, wherein the first DNS server corresponds to the first network access point, and / or the first DNS server corresponds to the second service.

[0126] In some implementations, when the second terminal does not access the network via satellite, and / or when the second service is not deployed via satellite, the transceiver unit is also used to send fourth address information to the second network element. The fourth address information is used to determine a fourth application server deployed on the ground, and the fourth application server is used to provide the second service to the second terminal.

[0127] In some implementations, the communication device may include modules, units, or means for performing the methods / operations / steps / actions described in the fourth aspect and any possible implementation of the fourth aspect, which may be hardware circuits, software, or a combination of hardware circuits and software.

[0128] In some implementations, the communication device includes a processing unit and a transceiver unit. The transceiver unit is used to receive a query message, which includes third address information and second service information; the processing unit is used to determine a third application server based on the third address information and the second service information, wherein the third application server has a connection with a fourth satellite, the third application server is used to provide the second service to a second terminal, the fourth satellite is used to provide access service to the second terminal, and the third address information is used to indicate the fourth satellite, or the third address information is used to indicate a satellite connected to the fourth satellite.

[0129] In some implementations, the processing unit is specifically used to: determine the third application server based on the third address information, the second service information, and the ephemeris information.

[0130] In some implementations, the third address information is the address information of the fourth network element, which is deployed on the fourth satellite, or the satellite on which the fourth network element is deployed is connected to the fourth satellite.

[0131] In some implementations, the transceiver unit is also used to: send a response message to the query message, the response message including the address of the third application server.

[0132] In a seventh aspect, a computer-readable storage medium is provided, on which a computer program or instructions are stored, which, when executed, cause the first aspect and any possible method of the first aspect to be performed (or implemented), or cause the second aspect and any possible method of the second aspect to be performed (or implemented), or cause the third aspect and any possible method of the third aspect to be performed (or implemented), or cause the fourth aspect and any possible method of the fourth aspect to be performed (or implemented).

[0133] Eighthly, a computer program product is provided, comprising a computer program or instructions that, when executed, cause the first aspect and any possible method of the first aspect to be performed (or implemented), or cause the second aspect and any possible method of the second aspect to be performed (or implemented), or cause the third aspect and any possible method of the third aspect to be performed (or implemented), or cause the fourth aspect and any possible method of the fourth aspect to be performed (or implemented).

[0134] A ninth aspect provides a communication device comprising at least one processor configured to execute (or implement) any of the possible methods of the first aspect, or any of the possible methods of the second aspect, or any of the possible methods of the third aspect, or any of the possible methods of the fourth aspect, by executing a computer program (or computer-executable instructions) stored in a memory, and / or by logic circuitry.

[0135] In one possible implementation, the device further includes a memory. In another possible implementation, at least one of the aforementioned processors and the memory are integrated together. In yet another possible implementation, the memory is located outside the communication device. The processor can be one or more.

[0136] In some possible implementations, the memory may be used to store part or all of the computer programs or instructions necessary for implementing the functions involved in the first aspect above. In some possible implementations, the memory may be used to store part or all of the computer programs or instructions necessary for implementing the functions involved in the second aspect above. In some possible implementations, the memory may be used to store part or all of the computer programs or instructions necessary for implementing the functions involved in the third aspect above. In some possible implementations, the memory may be used to store part or all of the computer programs or instructions necessary for implementing the functions involved in the fourth aspect above.

[0137] In one possible implementation, the communication device further includes a communication interface for communicating with other devices, such as transmitting or receiving data and / or signals. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, input / output interface, or other types of communication interface.

[0138] In one implementation, the communication device of the fifth, sixth or ninth aspect mentioned above can be a communication module in the device, or a chip or chip system in the terminal device.

[0139] In a tenth aspect, a chip is provided, including a processor for calling a computer program or computer instructions in a memory to cause the processor to execute or implement any of the implementations of the first aspect, or to cause the processor to execute or implement any of the implementations of the second aspect, or to cause the processor to execute or implement any of the implementations of the third aspect, or to cause the processor to execute or implement any of the implementations of the fourth aspect.

[0140] In some implementations, the processor is coupled to the memory via an interface.

[0141] Eleventhly, a communication system is provided. In some implementations, the communication system includes a first network element and a third network element, wherein the first network element is used to execute the first aspect and any possible implementation thereof, and the third network element is used to execute the second aspect and any possible implementation thereof. In other implementations, the communication system includes a first network element and a first DNS server, wherein the first network element is used to execute the third aspect and any possible implementation thereof, and the first DNS server is used to execute the fourth aspect and any possible implementation thereof.

[0142] The description of the beneficial effects of any of the fifth to eleventh aspects can be made by referring to the description of the beneficial effects of any implementation of the first or third aspect. Attached Figure Description

[0143] Figure 1 is a schematic diagram of a communication system.

[0144] Figure 2 is a schematic diagram of another communication system.

[0145] Figure 3 is a schematic flowchart of an edge application server (EAS) discovery method.

[0146] Figure 4 is a schematic diagram of an NTN scenario provided by an embodiment of this application.

[0147] Figure 5 is a schematic flowchart of a communication method provided in an embodiment of this application.

[0148] Figure 6 is a schematic flowchart of another communication method provided in an embodiment of this application.

[0149] Figure 7 is a schematic flowchart of another communication method provided in an embodiment of this application.

[0150] Figure 8 is a schematic flowchart of another communication method provided in an embodiment of this application.

[0151] Figure 9 is a schematic flowchart of another communication method provided in an embodiment of this application.

[0152] Figure 10 is a schematic block diagram of a communication device provided in an embodiment of this application.

[0153] Figure 11 is a schematic diagram of another communication device provided in an embodiment of this application.

[0154] Figure 12 is a schematic diagram of a chip system provided in an embodiment of this application.

[0155] Figure 13 is a schematic diagram of another chip system provided in an embodiment of this application. Detailed Implementation

[0156] In this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0157] I. In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can mean: a, or, b, or, c, or, a and b, or, a and c, or, b and c, or, a, b, and c. Here, a, b, and c can each be single or multiple.

[0158] II. In this application, the terms "first," "second," and various numerical designations (e.g., #1, #2, etc.) indicate distinctions made for ease of description and are not intended to limit the scope of the embodiments of this application. For example, they may distinguish different messages, rather than describing a specific order or sequence. It should be understood that such descriptions can be interchanged where appropriate to describe solutions other than those in the embodiments of this application.

[0159] Third, in this application, descriptions such as "when," "under the circumstances," and "if" all refer to the device making corresponding processing under certain objective circumstances, and are not time-limited, nor do they require the device to make a judgment action when implementing it, nor do they imply any other limitations.

[0160] IV. In this application, "instruction" or "for instruction" can include both direct (or explicit) and indirect (or implicit) instruction. When describing instruction information as indicating A, it can include whether the instruction information directly or indirectly indicates A, but does not necessarily mean that the instruction information carries A. For example, in the case of indirect (or implicit) instruction, the receiving end of the instruction information can obtain A based on the parameters indicated by the instruction information, combined with other rules or parameters, or through deduction.

[0161] V. The indication methods involved in the embodiments of this application should be understood to cover various methods that enable the party to be indicated to obtain the information to be indicated. The information to be indicated can be sent as a whole or divided into multiple sub-information and sent separately. Moreover, the sending period and / or sending time of these sub-information can be the same or different. This application does not limit the sending method, for example.

[0162] VI. In this application, "protocol" can refer to standard protocols in the field of communications, such as 5G protocols, new radio (NR) protocols, and related protocols applied to future communication systems; this application does not limit this term. "Predefined" can include predefined terms, such as protocol definitions. "Preconfiguration" can be implemented by pre-storing corresponding codes, tables, or other means that can be used to indicate relevant information in the device; this application does not limit the implementation method.

[0163] VII. In this application, "communication" can also be described as "data transmission," "information transmission," "data processing," etc. "Transmission" includes "sending" and "receiving." For example, transmission can be uplink transmission, such as a terminal device sending a signal to a network device; transmission can also be downlink transmission, such as a network device sending a signal to a terminal device; transmission can also be sidelink transmission, such as a terminal device sending a signal to another terminal device. For example, "transmission" can be air interface level transmission, or it can be signal transmission from a chip input (I) / output (O) port, rather than air interface level transmission.

[0164] 8. In this application, terms such as “message”, “information”, “signal” or “information element (IE)” can be used interchangeably. There are no restrictions on the name of the message or information, as long as it can achieve the corresponding function.

[0165] 9. "Sending information to XX (device)" can be understood as the destination of the information being that device. This can include sending information directly or indirectly to that device. "Receiving information from XX (device), or receiving information from XX (device)" can be understood as the source of the information being that device. This can include receiving information directly or indirectly from that device. Information may undergo necessary processing between the source and destination, such as format changes, but the destination can understand the valid information from the source. Similar expressions in this application can be understood in a similar way, and will not be repeated here. Furthermore, "sending" can also be understood as the "output" of the chip interface, and "receiving" can also be understood as the "input" of the chip interface. In other words, "sending" or "receiving" can occur between devices, for example, between network devices and terminal devices via an air interface. "Sending" or "receiving" can also occur within a device, for example, between components, modules, chips, software modules, or hardware modules within the device via a bus, wiring, or interface.

[0166] 10. In this application, terms such as "exemplarily" and "for example" are used to indicate examples, illustrations, or descriptions to present concepts in a specific manner. Any embodiment or design described as an "example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. In the embodiments of this application, the terms "of," "corresponding (relevant)," "corresponding," and "associate" may sometimes be used interchangeably, and it should be noted that their intended meanings are consistent unless their distinctions are emphasized.

[0167] XI. In this application, configuration can be signaling configuration or can be described as configuring signaling. For example, signaling configuration includes configuration using signaling sent by network devices, which can be radio resource control (RRC) messages, downlink control information (DCI) messages, or system information blocks (SIBs). Another example is signaling configuration between network devices. These network devices can include access network devices, core network devices, or management plane devices, etc. Optionally, signaling configuration can also be configured to terminal devices or network devices using pre-configured signaling, or configured to terminal devices or network devices through pre-configuration. Here, pre-configuration means defining or configuring the values ​​of corresponding parameters in advance using a protocol, and storing them in the terminal device or network device during communication. Pre-configured messages can be modified or updated when the terminal device or network device is connected to the network.

[0168] 12. This application will present various aspects, embodiments, or features relating to systems that may include multiple devices, components, modules, etc. Each system may include devices, components, modules, etc., other than those illustrated, and / or may not include all and all of the devices, components, modules, etc. discussed in conjunction with the accompanying drawings.

[0169] Thirteen, the business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0170] XIV. In the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The terms "comprising," "including," "having," and their variations all mean "including but not limited to," unless otherwise specifically emphasized.

[0171] The technical solutions of this application embodiment can be applied to various communication systems, including but not limited to: Long Term Evolution (LTE) systems, NR systems, and other fifth-generation (5G) communication systems. thThis includes various mobile communication systems such as 5G, narrowband Internet of Things (NB-IoT), enhanced machine-type communication (eMTC), enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), satellite communication systems, LTE-machine-to-machine (LTE-M) systems, and other systems that evolve after 5G, such as future mobile communication systems.

[0172] For example, satellite communication systems can include high altitude platform station (HAPS) communication or NTN systems such as unmanned aerial vehicles (UAVs). As another example, satellite communication systems can include integrated communication and navigation (ICAN) systems, global navigation satellite systems (GNSS), or ultra-dense low-Earth orbit (LEO) satellite communication systems.

[0173] The embodiments of this application are described below with reference to the accompanying drawings.

[0174] Figure 1 is a schematic diagram of a communication system 100. As shown in Figure 1, the communication system 100 includes a wireless access network 110 and a core network 120. Optionally, the communication system 100 may also include an Internet 130. The wireless access network 110 may include at least one access network device (111a and 111b in Figure 1) and at least one terminal device (112a-112j in Figure 1). The terminal device is connected to the access network device wirelessly. The access network device is connected to the core network 120 wirelessly or via a wired connection. The core network 120 may include one or more core network devices. The core network device and the access network device may be independent physical devices, or the functions of the core network device and the logical functions of the access network device may be integrated on the same physical device, or a single physical device may integrate some of the functions of the core network device and some of the functions of the access network device. Terminal devices and access network devices may be interconnected via wired or wireless connections. Wireless communication can occur between terminal devices, between access network devices, and between terminal devices and access network devices via air interface resources. For example, air interface resources may include at least one of time-domain resources, frequency-domain resources, code resources, and spatial resources. It should be noted that Figure 1 is a schematic diagram; the communication system 100 may also include other access network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in Figure 1.

[0175] Access network equipment can be any device with wireless transceiver capabilities. For example, access network equipment can be a base station used to connect terminal devices to a radio access network (RAN). Access network equipment is sometimes also referred to as an access network node, RAN device, AN device, RAN, or AN. It is understood that the names of devices with access network equipment functions may differ in systems employing different wireless access technologies. For ease of description, the apparatus providing wireless communication access functionality to terminal devices in this application embodiment is collectively referred to as RAN. In this application embodiment, access network equipment includes, but is not limited to: various forms of macro base stations (as shown in Figure 1, 111a), micro base stations or indoor stations (as shown in Figure 1, 111b), pico base stations, small stations, balloon stations, relay stations, access points, etc. Access network equipment can include evolved node Bs (eNBs or eNodeBs) in LTE, access points (APs), wireless relay nodes, wireless backhaul nodes, transmission points (TPs), or transmission reception points (TRPs) in Wi-Fi systems. It can also include next-generation NodeBs (gNBs) or transmission points (TRPs or TPs) in 5G systems, one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, and network nodes constituting a gNB or transmission point, such as baseband units (BBUs) or distributed units (DUs). Furthermore, it can include access network equipment, servers, or vehicle-mounted equipment in networks evolving after 5G. Access network equipment can also be modules or units that perform some of the functions of a base station; for example, it can be a central unit (CU) or a DU.

[0176] For example, access network equipment can be deployed on satellites. For instance, the satellites can be low Earth orbit (LEO) satellites, medium Earth orbit (MEO) satellites, geostationary Earth orbit (GEO) satellites, or non-geostationary Earth orbit (NGEO) satellites, and so on.

[0177] In this embodiment, the apparatus for implementing the functions of the access network device can be the access network device itself, or it can be an apparatus capable of supporting the access network device in implementing the functions, such as a chip system, which can be installed in the access network device. The chip system can be composed of chips, or it can include chips and other discrete components.

[0178] In another possible scenario, multiple access network devices collaborate to assist the terminal in achieving wireless access, with each device performing a portion of the base station's functions. For example, the access network devices could be a CU, DU, CU (control plane, CP), CU (user plane, UP), or a radio unit (RU). The CU and DU can be separate entities or included in the same network element, such as a BBU. The RU can be included in radio equipment or radio units, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0179] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an open radio access network (O-RAN) system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software modules and hardware modules. The embodiments of this application do not limit the specific technology or specific device form used in the access network equipment.

[0180] Terminal equipment can be a device that provides voice and / or data connectivity to users; it can also be a device with wireless connectivity. Terminal equipment can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; it can also be deployed on water (such as on ships); and it can also be deployed in the air (such as on airplanes, balloons, and satellites). Terminal equipment can also be referred to as user equipment (UE), access terminal, terminal, subscriber unit, user station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, wireless network equipment, user agent, or user device. In this application embodiment, terminal devices include, but are not limited to: cellular phones, mobile phones, wireless data cards, wireless modems, tablets, laptop computers, notebook computers, handheld computers, mobile internet devices (MIDs), computers with wireless transceiver capabilities, cordless phones, session initiation protocol (SIP) phones, smartphones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handsets with wireless communication capabilities, computing devices or other devices connected to wireless modems, in-vehicle devices (e.g., cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), wearable devices (e.g., smartwatches, smart bracelets, pedometers, smart glasses, etc.), satellite terminals, terminal devices in the Internet of Things or the Internet of Vehicles, as well as any form of terminal in future networks, relay user equipment, or terminals in future evolved public land mobile networks (PLMNs), etc.Terminal devices can also be virtual reality (VR) devices, augmented reality (AR) devices, smart point-of-sale (POS) machines, customer-premises equipment (CPE), light UE, reduced capability UE (REDCAP UE), machine-type communication (MTC) terminals, terminal devices in industrial control, terminal devices in self-driving, terminal devices in telemedicine, terminal devices in smart grids, wireless terminals in transportation safety, terminal devices in smart cities, terminal devices in smart homes, tactile terminal devices, smart home devices (e.g., refrigerators, televisions, air conditioners, electricity meters, etc.), smart robots, robotic arms, workshop equipment, wireless terminals in self-driving, or flying devices (e.g., smart robots, hot air balloons, drones, airplanes), etc. The terminal device can also be a vehicle device, such as a complete vehicle device, an in-vehicle module, an in-vehicle chip, an on-board unit (OBU), or a telematics box (T-BOX). The terminal device can also be other devices with terminal functions; for example, it can be a device that functions as a terminal in device-to-device (D2D) communication. This application does not limit the scope of the embodiments in this regard.

[0181] In this application embodiment, the device for implementing the functions of the terminal device can be the terminal device itself, or it can be any device capable of supporting the terminal device in implementing the functions, such as a chip or chip system. This device can be installed in the terminal device. The chip system can consist of chips or include chips and other discrete components. In the technical solution of this application embodiment, the device for implementing the functions of the terminal device is referred to as the terminal device, which can also be called a terminal. The following description may use a UE (User Equipment) as an example to illustrate the technical solution provided in this application embodiment.

[0182] The roles of base stations and terminals can be relative. For example, the helicopter or drone 112i in Figure 1 can be configured as a mobile base station. For terminals 112j that access the wireless access network 110 via 112i, terminal 112i is a base station; however, for base station 111a, 112i is a terminal, meaning that 111a and 112i communicate via a wireless air interface protocol. Of course, 111a and 112i can also communicate via a base station-to-base station interface protocol. In this case, relative to 111a, 112i is also a base station. Therefore, both base stations and terminals can be collectively referred to as communication devices. 111a and 111b in Figure 1 can be called communication devices with base station functions, and 112a-112j in Figure 1 can be called communication devices with terminal functions.

[0183] Access network devices and terminal devices can communicate via wireless links. The transmission link from the access network device to the terminal device can be called a downlink (DL) or downlink channel, used for transmitting downlink signals. The transmission link from the terminal device to the access network device can be called an uplink (UL) or uplink channel, used for transmitting uplink signals. The transmission link from one terminal device to another can be called a sidelink (SL) or sidelink channel, used for transmitting sidelink signals.

[0184] Figure 2 is a schematic diagram of another communication system. Figure 2 shows multiple nodes that can communicate with each other. The solid line connecting two nodes in Figure 2 indicates that communication is possible between those two nodes. Figure 2 is only an example; the communication system in this embodiment may include more nodes, and there may be other communication paths between the nodes. This application does not impose any limitations.

[0185] The communication system shown in Figure 2 may include access network equipment (represented by RAN(AN) in Figure 2), terminal equipment (represented by UE in Figure 2), data network (DN), local DN, and at least one network function (NF). For example, at least one NF may include at least one of the following: network exposure function (NEF), application function (AF), access and mobility management function (AMF), session management function (SMF), or edge application server discovery function (EASDF).

[0186] The Network Front-End (NEF) can expose certain network functionalities to applications in a controlled manner. For example, the NEF can reside between the 5G core network and external third-party application functionalities (and possibly partly within the Application Front-End), managing external applications that expose network data. For instance, other devices accessing data within the 5G core network can do so through the NEF. The NEF can provide appropriate security safeguards to ensure that external applications can access the 3G Partnership Program (3GPP). rd This application addresses the security of Generation Partnership Project (3GPP) networks, providing functions such as open access to external application quality of service (QoS) customization capabilities, mobility state event subscription, and AF request distribution. In future communication systems, the network capability opening function may still be called NEF, or it may have other names; this application is not limited to these.

[0187] Application Function (AF) can refer to various application-layer services. AF can be used to convey application-side requests to the network side. For example, requests may include QoS requirements or user state event subscriptions. AF can provide various application service data to the control plane network elements of the operator's communication network, or obtain network data and control information from the control plane network elements of the communication network. AF can be deployed on the operator's network (e.g., an application within the operator's network) or deployed by a third party. For example, an AF can be a Voice Over Long-Term Evolution (Volte) AF, or a third-party AF (such as a video server or game server). In 5G communication systems, application function network elements can be application functions (AFs). In future communication systems, application function network elements may still be AF network elements, or they may have other names; this application is not limited to these. For example, application function network elements can also be called application servers or service servers.

[0188] The Access and Mobility Management (AMF) can be responsible for access and mobility management in mobile communication networks. For example, the AMF can implement terminal attachment, tracking area update procedures, or other functions in the mobile network. Furthermore, the AMF can provide non-access stratum (NAS) message termination, registration management, registration area management, connection management, reachability management, allocation of tracking area lists (TA lists), access authorization, authentication, and mobility management. The AMF can transparently route session management (SM) messages to session management network elements. The AMF can provide a session management message transmission channel for the UE and the session management function (SMF), providing authentication and authorization functions for user access, and serving as the core network control plane access point for the terminal and radio. In 5G communication systems, the access and mobility management network element can be the AMF. In future communication systems, the access and mobility management function can still be the AMF, or it can have other names; this application is not limited to this.

[0189] Session Management Functions (SMFs) can be used for session and bearer management in mobile networks, such as session establishment, modification, and release. Specific functions include allocating and managing Internet Protocol (IP) addresses for the UE and selecting user plane function network elements (MPFs) that provide packet forwarding capabilities. For example, a session management network element can select a suitable MPF for the UE based on the UE's request and the policy control information of the policy control network element, establish a session with that MPF, and generate QoS and charging rules. The session management network element can control the data forwarding and processing behavior of MPFs. In 5G communication systems, the session management network element can be a session management function (SMF). In future communication systems, the session management network element may still be an SMF element, or it may have other names; this application is not limited to these.

[0190] A Data Network (DN) can be used to provide data transmission services for terminal devices. A DN can be a private network, such as a Local Area Network (LAN), a public data network (PDN), such as the Internet, a dedicated network jointly deployed by operators, such as a configured IP Multimedia Core Network Subsystem (IMS) service, or a local DN. A DN can also originate from a third party.

[0191] At least one edge application server (EAS) can be deployed in the local DN. The EAS provides services to the terminals at the edge of the network.

[0192] User plane functional elements (UPFs) can be used to process user packets, such as forwarding or accounting. They can perform functions like routing, forwarding, QoS flow processing, threshold control, traffic monitoring, authentication, and packet detection or reporting. UPFs can also be used for UE IP address management or core network (CN) tunnel information management. UPFs can reside in the user plane of the core network, providing UEs with high-speed, efficient, and flexible data transmission services. Furthermore, UPFs can perform packet filtering, traffic shaping, or accounting based on control plane instructions, enabling fine-grained management and control of user data flows. UPFs can connect to access network equipment via the N3 interface and to the data network via the N6 interface, thus enabling data transmission between the UE and the external data network. UPFs can also be referred to as Protocol Data Unit (PDU) session anchors (PSAs). In 5G communication systems, user plane function network elements can be user plane functions (UPF). In future communication systems, user plane function network elements can still be UPF network elements, or they can have other names. This application does not limit this.

[0193] EASDF can be used to assist in EAS discovery. For example, EASDF can process DNS messages according to instructions from the SMF. For instance, EASDF can report DNS messages to the SMF, add address information to DNS query messages, forward DNS query messages to a DNS server, forward DNS response messages to the UE, or perform other operations. The functionality of EASDF can be found in 3GPP technical specification (TS) 23.548.

[0194] The multi-anchor PDU session architecture is described below with reference to Figure 2.

[0195] To support selective traffic routing to the DN or to support session continuity mode, the SMF can insert multiple UPFs into the user plane of a PDU session to control the user plane path of the PDU session, allowing a PDU session to access the DN simultaneously through multiple N6 interfaces. Each UPF accessing the DN can support the PDU Session Anchor (PSA) function, meaning a PDU session can access the same DN through multiple anchors.

[0196] In a PDU session, the UPF directly connected to the DN via N6 can be called a PSA. The anchor UPF used for local branching can be called a local PDU session anchor point (local PSA, L-PSA). The L-PSA can be connected to the local DN via N6. The anchor UPF used for central aggregation can be called a central PDU session anchor point (central-PSA, C-PSA). The C-PSA can be connected to other DNs via N6. A UPF acting as a branching point can be called a branching point (BP) or an uplink classifier (UL-CL or ULCL).

[0197] In some examples, in a multi-anchor PDU session architecture, the PDU session has a splitting point UPF (e.g., called UL-CL / BP). This splitting point UPF can perform traffic splitting of user plane packets based on the source / destination IP address of the user plane packets. For example, the UL-CL UPF can split traffic based on the destination IP address of the uplink packets. Specifically, the UL-CL UPF can forward user plane packets to C-PSA or L-PSA through different tunnels (e.g., a tunnel between UL-CL and C-PSA, or a tunnel between UL-CL and L-PSA) based on the destination IP address. As another example, the BP UPF can split traffic based on the source IP address of the uplink packets.

[0198] The routing rules of the UPF (User-defined load balancer) can be configured by the SMF (Small and Medium Filtering Unit). For example, the SMF can control the insertion, modification, and removal of the UPF, or the configuration or modification of its routing rules, etc., through the N4 interface between the SMF and the UPF.

[0199] In the architecture shown in Figure 2, the interface names and functions between the various network elements are as follows:

[0200] 1. N1: The interface between AMF and UE, which can be used to transmit QoS control rules to UE, etc.

[0201] 2. N2: The interface between AMF and (R)AN, which can be used to transmit radio bearer control information from the core network side to the RAN.

[0202] 3. N3: The interface between RAN and UPF, used to transmit uplink or downlink user plane data between RAN and UPF.

[0203] 4. N4: The interface between SMF and UPF, which can be used to transmit information between the control plane and the user plane, including the distribution of forwarding rules, QoS control rules, traffic statistics rules, etc. from the control plane to the user plane, as well as the reporting of information from the user plane.

[0204] 5. N6: The interface between UPF and DN, used to transmit uplink or downlink user data streams between UPF and DN.

[0205] 6. N9: The interface between two UPFs, used to transmit uplink or downlink user data streams.

[0206] The communication system in this application embodiment may include some or all of the nodes shown in Figure 1 and / or Figure 2, and may also include other nodes. For example, the communication system in this application embodiment may include a network slice selection function (NSSF), an authentication server function (AUSF), a network function repository function (NRF), a policy control function (PCF), unified data management (UDM), or other nodes. Further details will not be elaborated further.

[0207] The aforementioned network elements or functions can be network components in hardware devices, software functions running on dedicated hardware, or virtualization functions instantiated on a platform (e.g., a cloud platform). These network elements or functions can be implemented by a single device, by multiple devices working together, or as a functional module within a single device; this application does not specifically limit their implementation in this regard.

[0208] The naming conventions described above are defined solely for the purpose of distinguishing different functions and do not constitute a limitation on this application. This application does not preclude the possibility of using other naming conventions in 5G networks and other future networks. For example, in future communication networks, some or all of the aforementioned network terminology may be retained from 5G, or other names may be used.

[0209] The term "network element" can also be referred to as an entity, device, apparatus, or module, etc., and is not specifically limited in this application. Furthermore, in this application, for ease of understanding and explanation, the description of "network element" is omitted in some descriptions. For example, the AMF network element is abbreviated as AMF. In this case, "AMF" can be understood as an AMF network element or an AMF entity. The following omits descriptions of the same or similar cases.

[0210] In edge computing (EC) deployment scenarios, certain services may be provided by multiple Application Servers (EASs) deployed at the network edge (e.g., local DN). The services and content provided by these EASs can be the same as those provided by application servers (ASs) deployed in other network locations (e.g., network center). EASs and ASs can share the same address. When a UE needs to access these services, the UE needs to obtain the appropriate EAS address information.

[0211] Figure 3 is a schematic flowchart of an EAS discovery method 300. Optional operations in method 300 are shown in Figure 3 with dashed lines. Method 300 is described below with reference to Figure 3.

[0212] S310, SMF configures DNS processing rules for EASDF.

[0213] For example, during the session establishment process, after the SMF selects EASDF, the SMF can configure DNS processing rules on EASDF. For instance, there can be multiple DNS processing rules, each corresponding to a PDU session.

[0214] In some possible implementations, after configuring EASDF, SMF can send the EASDF address information to the UE, instructing the UE to use the EASDF address as the address of the UE's default DNS server, that is, the default address for the UE to send DNS request messages.

[0215] S320, the UE sends a DNS request message to the EASDF. Correspondingly, the EASDF receives the DNS request message from the UE.

[0216] In some possible implementations, the S320 can be executed after the PDU session establishment process.

[0217] DNS request messages can be used to request address information for EAS.

[0218] For example, a DNS request message may include information about the service. For instance, the service information could be a fully qualified domain name (FQDN).

[0219] For example, address information may include: IP address (e.g., IP version 4 (IPv4) address or IP version 6 (IPv6) address), media access control (MAC) address, or other information that can indicate an address, which is not limited in this application.

[0220] DNS request messages can also be called DNS query messages, DNS messages, or other names.

[0221] S330, EASDF matches DNS processing rules based on DNS request messages.

[0222] For example, EASDF can match the source address of a DNS request message with the source address in at least one DNS processing rule.

[0223] EASDF can serve multiple PDU sessions, each of which can correspond to different DNS processing rules. Therefore, after EASDF receives a DNS request message, it can determine the PDU session corresponding to the DSN request message and the DNS processing rule corresponding to that PDU session (denoted as DNS processing rule 1) based on the source address.

[0224] Furthermore, EASDF can match the FQDN in the DNS request message with the FQDN range in DNS processing rule 1. If the FQDN in the DNS request message is within the range, EASDF can execute S340. If the FQDN in the DNS request message is not within the range, EASDF can send the DNS request message to the central DNS (C-DNS) server.

[0225] The DNS processing rule can also be called the DNS message handling rule or other names, which are not limited in this application.

[0226] S340, EASDF sends an indication of the FQDN to SMF. Correspondingly, SMF receives the FQDN indication from EASDF. This indication may specify the FQDN included in the DNS request message.

[0227] S345, the SMF sends address information to the EASDF. Correspondingly, the EASDF receives address information from the SMF.

[0228] This address information can represent the location information of the UE. For example, this address information could be the address information of a network element that is close to the UE.

[0229] In some possible implementations, after the SMF receives the indication information of the FQDN, the SMF can determine the address information based on the FQDN, EAS deployment information, or UE location information.

[0230] S350, EASDF sends a DNS request message to the C-DNS server. Correspondingly, the C-DNS server receives the DNS request message from EASDF.

[0231] In particular, the DNS request message in S350 can carry an EDNS client subnet (ECS) option field, the value of which can be the address information provided by SMF to EASDF in S345.

[0232] In some possible implementations, EASDF can generate an ECS option based on the address information received from the SMF and add the ECS option to the DNS request message received from the UE.

[0233] The ECS option can be an extension item in the DNS message, used to represent the UE's location information. For example, the address information carried by the ECS option can be the address information of a network element that is close to the UE.

[0234] The above S345 can also be understood as SMF instructing EASDF to use this address information as an ECS option. After receiving the DNS request message including the ECS option, the C-DNS server can return the address of the server that is closer to the address in the ECS option (or has high IP affinity).

[0235] S355, the C-DNS server sends a DNS response message to EASDF. Correspondingly, EASDF receives the DNS response message from the C-DNS server.

[0236] The DNS response message may include the FQDN and the address information of the EAS. This FQDN may be the same as the FQDN in the DNS request message.

[0237] In S330, if the FQDN in the DNS request message is not within the range of FQDNs indicated by the DNS processing rules, EASDF can directly forward the DNS request message to the default DNS server without going through S340 to S345 (i.e., without adding the ECS option). In this case, the server queried is generally the address of a remote server, such as a central cloud server.

[0238] S360, EASDF matches DNS processing rules based on DNS response messages.

[0239] For example, EASDF can match the FQDN of the DNS response message with the FQDN in the DNS processing rule. If the match is successful, EASDF can execute S370. If the match fails, that is, the FQDN of the DNS response message is not within the range of FQDNs in the DNS processing rule, EASDF can directly forward the DNS response message to the UE.

[0240] For example, the above matching can also be based on the EAS address information. For instance, EASDF can match the EAS address information of the DNS response message with the address information in the DNS processing rules. If the match is successful, EASDF can execute S370. If the match fails, that is, if the address information of the DNS response message is not within the range of the address information in the DNS processing rules, EASDF can directly forward the DNS response message to the UE.

[0241] For example, the above matching can also be based on the combination of FQDN and EAS address information. That is, EASDF can execute S370 only if the address information of FQDN and EAS are matched successfully at the same time. Otherwise, EASDF can directly forward the DNS response message to the UE.

[0242] The above matching can also be based on other information, which is not limited in this application.

[0243] S370, EASDF sends the EAS address information to SMF. Correspondingly, SMF receives the EAS address information from EASDF.

[0244] In some possible implementations, EASDF may store the DNS response message locally.

[0245] In some possible implementations, EASDF may also indicate the FQDN to SMF.

[0246] S374, SMF configuration shunt point.

[0247] For example, SMF can insert offloading points (e.g., UL-CL and / or BP) and local anchors (e.g., L-PSA) based on EAS address information or EAS deployment information. SMF can configure offloading rules on offloading points and local anchors.

[0248] S376, the SMF sends an indication message to the EASDF, instructing the EASDF to forward the DNS response message to the UE. Correspondingly, the EASDF receives this indication message from the SFM.

[0249] After the SMF configures the routing point, the SMF can instruct the EASDF to send cached DNS response messages to the UE.

[0250] Figure 4 is a schematic diagram of an NTN scenario provided by an embodiment of this application. The following describes some examples of EAS deployment on satellites in an NTN scenario, with reference to Figure 4.

[0251] In NTN scenarios, the RAN, UPF, and EAS can all be deployed on satellites (e.g., LEO satellites). This allows UEs accessing the network via satellite to access the onboard EAS. Compared to UEs accessing the ground-based EAS via satellite, this approach reduces service latency and minimizes satellite-to-ground interactions.

[0252] Because satellites have limited payloads, the RAN, UPF, and EAS may not be deployed on the same satellite. For example, referring to Figure 4, the UEP and EAS1 can be deployed on satellite 1; the RAN and UPF can be deployed on satellite 2; EAS 3 can be deployed on satellite 3; and EAS 4 can be deployed on satellite 4. The UE can access the network through the RAN deployed on satellite 2, thereby accessing EAS1 on satellite 1 and obtaining the edge application services provided by EAS 1.

[0253] Those skilled in the art will understand that with a large number of satellites moving at high speeds, different satellites may not always be able to communicate. For example, referring to Figure 4, at a certain moment, satellite 1 and satellite 2 are connected and can communicate. Satellite 3 and satellite 4 are also connected and can communicate. However, satellite 1 and satellite 3 are not connected and cannot communicate.

[0254] In some examples, SMF, EASDF, DNS servers, or other network elements can be deployed on the ground. SMF, EASDF, DNS servers, and UEs can be used to perform the EAS discovery process.

[0255] If method 300 is directly applied for EAS discovery, it is difficult to guarantee that the satellites deployed by the EAS can communicate with the satellites deployed by the RAN, thus preventing the UE from accessing the EAS. For example, in method 300, the C-DNS server returns the address information of EASs that are close to the address or have high IP affinity based on the address in the ECS option field; alternatively, the C-DNS server considers the load of the EAS and returns the address information of EASs that can provide services. However, the C-DNS server in method 300 cannot consider whether the EAS is deployed on a satellite, nor can it consider whether there is a connection between the satellites deployed by the EAS and the satellites accessed by the UE.

[0256] For example, in method 300, the DNS might return the address information of EAS 3. Since there is no connection between satellite 2 and satellite 3, the UE cannot access EAS 3 on satellite 3 via the RAN on satellite 2. In other words, the UE cannot access this EAS and therefore cannot access services.

[0257] Therefore, in NTN scenarios, how to enable terminals (e.g., UEs) to access services is an urgent problem to be solved.

[0258] Figure 5 is a schematic flowchart of a communication method 500 provided in an embodiment of this application. Method 500 improves communication availability by allowing the terminal to access services normally through either an EAS fallback to a terrestrial AS or a terminal redirection. Optional operations in method 500 are shown in dashed lines in Figure 5. Exemplarily, method 500 can be applied to a satellite communication system (e.g., a regenerative satellite communication system). The various nodes involved in method 500 are described below.

[0259] Unless otherwise specified, the first terminal in this application can be the terminal device itself, a component within the terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the terminal device's functions. For ease of description, UE#1 will be used as an example below.

[0260] Unless otherwise specified, the first network element in this application can be the device itself capable of implementing session management functions, a component within that device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the session management functions. For ease of description, the first network element will be used as an example below.

[0261] The first network element can be used for session management and / or connection management. For example, the first network element can be called SMF or other names, and this application does not limit the specific name of the first network element. The first network element can be a network element (or a function within a network element) used for session management and / or connection management in a communication system such as a 5G communication system or a future communication system.

[0262] For ease of description and understanding, the following description will take SMF as the first network element.

[0263] Unless otherwise specified, the second network element in this application can be the device itself capable of discovering or selecting EAS, a component within that device (e.g., a processor, chip, or chip system), or a logical module or software capable of implementing all or part of the EAS discovery function. Examples include EASDF, UPF, DNS server, or other devices capable of collaboratively or independently performing EAS discovery; no limitation is made. For ease of description, EASDF will be used as an example below.

[0264] The third network element can be used to provide the first network element with one or more of the following: the location information of the first terminal, the access type, and the accessed satellites. There is no limitation on its name. The third network element can be the device itself that can perform the above functions, or a component in the device (e.g., a processor, chip, or chip system), or a logic module or software that can perform all or part of the above functions.

[0265] For example, the third network element can be the device itself capable of implementing access and / or mobility management functions, a component within that device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the access and / or mobility management functions. For ease of description, the following description uses AMF as an example.

[0266] The following section describes each operation in method 500 with reference to Figure 5.

[0267] S530, the SMF receives first information from the EASDF, wherein the first information is used to instruct the first application server. Correspondingly, the EASDF sends the first information to the SMF.

[0268] The phrase "the first information is used to indicate the first application server" can also be understood as: the SMF can determine the first application server based on the first information, or the first information is information about the first application server, or the first information corresponds to the first application server.

[0269] For example, the first information may include the identifier of the first application server, address information, or other information capable of identifying the first application server. For example, the identifier of the first application server may include: an identifier field, a domain name pointing to the first application server, etc., which are not limited in this application.

[0270] For example, address information may include: IP address (e.g., IPv4 address or IPv6 address), MAC address or other information that can indicate an address, which is not limited in this application.

[0271] For ease of description, the following description will use IP addresses (or simply "IP") as the address information. However, those skilled in the art will understand that "IP address" can be replaced with other address information.

[0272] For example, the first information can be carried in a DNS context notification message, such as a Neasdf_DNSContext_Notify message. The first information can also be carried in other messages, which are not limited in this application.

[0273] The first application server can be a server device, a component within the server device, a virtual machine, an instance, a container, or a logical module or software that provides all or part of the application service functions. For example, the first application server can be an Edge Application Server (EAS).

[0274] For ease of description, the following description will take EAS as the first application server, and we will refer to the first application server as EAS#1.

[0275] EAS#1 can be deployed on the first satellite (denoted as EAS#1 satellite). Thus, EAS#1 can also be referred to as an onboard EAS. The EAS#1 satellite can deploy only EAS#1, or it can deploy EAS#1 and other servers (and / or other access network, core network equipment), which is not limited in this application.

[0276] Specifically, EAS#1 can be used to provide the first service to UE#1; or it can be understood as EAS#1 being used to provide the first service to UE#1; or it can be understood as UE#1 being able to obtain the first service by accessing (or) EAS#1; or it can be understood as EAS#1 being used to enable UE#1 to access the first service; or it can be understood as EAS#1 being used for UE#1 to access the first service; or it can be understood as UE#1 being able to access EAS#1 to receive the first service; or it can be understood as UE#1 being able to access the first service through EAS#1; or it can be understood as the first service being deployed / configured on EAS#1; or it can be understood as UE#1 accessing (or accessing) the first service through EAS#1; or it can be understood as EAS#1 being used for UE#1 to access (or access) the first service.

[0277] It is understandable that while EAS#1 can be used to provide the first service to UE#1, this does not mean that EAS#1 will necessarily successfully provide the first service to UE#1. In other words, UE#1 may not be able to successfully access EAS#1, or access the first service through EAS#1. For example, EAS#1 may not be able to communicate with the satellite currently accessed by UE#1 (e.g., there is no inter-satellite link between the satellite deployed by EAS#1 and the satellite accessed by UE#1 during a certain period of time), thus failing to provide the first service to UE#1. However, those skilled in the art will understand that EAS#1 has the capability to provide the first service to UE#1, but may not necessarily successfully provide the first service.

[0278] The type of the first service is not limited. For example, the first service can be any service type defined in 3GPP standards (e.g., those defined in 3GPP TS23.401 and 23.501, or those defined by future communication technology protocols), such as Short Message Service (SMS), IP Multimedia Subsystem (IMS), or any data network name (DNN) and / or network slice. For example, the first service can also be any service type understood by those skilled in the art, such as voice call service, video playback service, audio playback service, video conferencing service, online game service, electronic transaction service, or other data transmission-related services; this application does not impose specific limitations.

[0279] Optionally, the first information carries information about the first service. For example, the first information and the information about the first service may be carried in the same message, or the first information and the information about the first service may be sent simultaneously.

[0280] The information for the first service can indicate the first service. For example, the information for the first service can be its identification information or address information. For example, the identification information for the first service can be the FQDN corresponding to the first service.

[0281] UE#1 can access the network through the second satellite; in other words, UE#1 accesses the second satellite; in other words, UE#1 accesses the access network equipment deployed on the second satellite; in other words, the second satellite can be used to provide access services for UE#1; in other words, the access network equipment deployed on the second satellite is used to provide access services for UE#1; the second satellite can be the satellite that UE#1 accesses.

[0282] As an example, the second satellite can be deployed with a RAN (denoted as RAN#1). Thus, RAN#1 can also be referred to as the on-board RAN.

[0283] RAN#1 can be an access network device, a component within the access network device (e.g., a processor, chip, or chip system), or a logic module or software that can implement all or part of the access functions.

[0284] UE#1 accesses the network through the second satellite, which can be understood as UE#1 accessing the network through RAN#1 on the second satellite; in other words, UE#1 accesses RAN#1 on the second satellite; in other words, RAN#1 on the second satellite can be used to provide access services for UE#1; in other words, RAN#1 on the second satellite can be the RAN that UE#1 accesses.

[0285] The second satellite can be a satellite deployed in RAN#1. For ease of understanding and description, the second satellite can be referred to as RAN#1 satellite. RAN#1 satellite can be deployed solely in RAN#1, or it can be deployed in conjunction with RAN#1 and other network elements (or other servers). This application does not impose any limitations on this.

[0286] RAN#1 and EAS#1 satellites can be different satellites.

[0287] There may be no connection between the second satellite (e.g., RAN#1 satellite) and the first satellite (e.g., EAS#1 satellite); for example, RAN#1 satellite and EAS#1 satellite cannot communicate via an inter-satellite link.

[0288] The term "connection" can include inter-satellite links. That is, there may be no inter-satellite link between RAN#1 and EAS#1 satellites. The term "connection" can also be replaced with "link" or other names; this application does not limit the choice.

[0289] In some possible implementations, after S530, method 500 further includes: the SMF determining that there is no connection between the RAN#1 satellite and the EAS#1 satellite.

[0290] In some examples, the SMF can determine that there is no connection between the RAN#1 satellite and the EAS#1 satellite based on ephemeris information. The ephemeris information can be configured within the SMF or obtained by the SMF from other network elements (e.g., the AMF); this application does not limit the source of the ephemeris information.

[0291] In other examples, the SMF can determine, based on other information, that there is no connection between the RAN#1 satellite and the EAS#1 satellite. See the examples below for details; they will not be elaborated upon here.

[0292] S560, SMF sends the second message.

[0293] The following are examples of the second information, referred to as Information Example 1 and Information Example 2, respectively.

[0294] Example 1: This second piece of information is used to identify the second application server.

[0295] The second application server can be a server device, a component within the server device, a virtual machine, an instance, a container, or a logical module or software that can provide all or part of the application service functions. For example, the second application server can be an AS (Application Server) or other server.

[0296] For ease of description, the following description will take AS as the second application server as an example, and we will refer to the second application server as AS#2.

[0297] AS#2 can be deployed on the ground. RAN#1 satellite can connect to the ground; for example, RAN#1 satellite can directly connect to a ground-based gateway station, and the gateway station can communicate with AS#2 via IP. Alternatively, RAN#1 satellite can connect to other satellites via inter-satellite links, and these other satellites can then directly connect to the ground-based gateway station, which in turn can communicate with AS#2 via IP. In this way, UE#1 can access AS#2 through RAN#1 satellite.

[0298] For ease of description, the following description uses the FQDN as the information for the first service as an example, denoted as FQDN#1. However, those skilled in the art will understand that the information for the first service is not limited to the FQDN format and can take other forms.

[0299] For example, the first service can also be understood as the service corresponding to the information of the first service (e.g., FQDN#1).

[0300] AS#2 can be used to provide the same services to UE#1 as EAS#1. For example, AS#2 can be used to provide the same FQDN (e.g., FQDN#1) to UE#1 as EAS#1.

[0301] For example, AS#2 can be used to provide the first service to UE#1; or it can be understood that AS#2 can be used to provide the service of the first service to UE#1; or it can be understood that UE#1 can obtain the service of the first service by accessing AS#2; or it can be understood that AS#2 can be used to enable UE#1 to access the first service; or it can be understood that AS#2 can be used for UE#1 to access the first service; or it can be understood that UE#1 can access AS#2 to receive the first service; or it can be understood that UE#1 can access the first service through AS#2; or it can be understood that the first service is deployed / configured on AS#2; or it can be understood that UE#1 accesses (or accesses) the first service through AS#2; or it can be understood that AS#2 is used for UE#1 to access (or access) the first service.

[0302] Alternatively, the above scheme can be understood as follows: AS#2 can be used to provide the first service to UE#1 via a second satellite (e.g., RAN#1 satellite); or AS#2 can be used to provide the first service to UE#1 via RAN#1 satellite; or AS#2 can be used to enable UE#1 to access the first service via RAN#1 satellite; or AS#2 can be used for UE#1 to access the first service via RAN#1 satellite; or UE#1 can access AS#2 via RAN#1 satellite to receive the first service; or UE#1 can access the first service via both AS#2 and RAN#1 satellites.

[0303] Alternatively, the above scheme can be understood as follows: AS#2 can be used to provide the first service to UE#1 through RAN#1 on the second satellite; or AS#2 can be used to provide the first service to UE#1 through RAN#1 on the second satellite; or AS#2 can be used to enable UE#1 to access the first service through RAN#1 on the second satellite; or AS#2 can be used for UE#1 to access the first service through RAN#1 on the second satellite; or UE#1 can access AS#2 through RAN#1 on the second satellite to receive the first service; or UE#1 can access the first service through AS#2 and RAN#1 on the second satellite.

[0304] The second information is used to determine AS#2, and may include: the second information is used to discover AS#2.

[0305] In some possible implementations, S560 includes: S562, where the SMF sends a second message to the EASDF.

[0306] Optionally, the second information includes the first address information. This first address information can be used to identify AS#2 deployed on the ground.

[0307] For example, in some possible implementations, EASDF can generate an ECS option based on the first address information, and the value of the ECS option can be the first address information.

[0308] Optionally, the first address information is the address information of a network element deployed on the ground. For example, the first address information could be the address information of a ground-based UPF. In this way, EASDF can discover (or determine) ASs that are close to the UPF (or have good IP affinity with the UPF). For example, EASDF uses the address information of the ground-based UPF as an ECS option in a DNS query message and sends this DNS query message to a DNS server (or DNS resolver). The DNS server, based on the ECS option, replies to EASDF in a DNS reply message with the address of the AS closest to the UPF. Through this mechanism, EASDF can discover (or determine) the ground-based AS#2. Those skilled in the art will understand that EASDF can send the address information of AS#2 to UE#1 via a DNS reply message, thereby enabling UE#1 to access the ground-based AS#2 when accessing via satellite (e.g., RAN#1 satellite).

[0309] Based on the above scheme, if there is no connection between the first satellite where the first application server (e.g., EAS#1) is located and the satellite (i.e., the second satellite) accessed by the first terminal (e.g., UE#1), the SMF can determine the second application server (e.g., AS#2) deployed on the ground, thereby enabling the first terminal to fall back to access the application server on the ground, so that the first terminal can access the service.

[0310] Information Example 2: This second piece of information is used to identify the third satellite.

[0311] The third satellite can be equipped with a RAN (denoted as RAN#2). Thus, RAN#2 can also be referred to as an on-board RAN.

[0312] RAN#2 can be an access network device, a component within the access network device (e.g., a processor, chip, or chip system), or a logic module or software that can implement all or part of the access functions.

[0313] The third satellite can be a satellite deployed in RAN#2. For ease of understanding and description, the third satellite can also be referred to as the RAN#2 satellite. The RAN#2 satellite can be deployed solely in RAN#2, or it can be deployed in conjunction with RAN#2 and other network elements (or other servers). This application does not impose any limitations on this.

[0314] The third satellite (e.g., RAN#2) can be connected to the first satellite (e.g., EAS#1). In other words, RAN#2 and EAS#1 can communicate with each other (e.g., an inter-satellite link exists between them, or RAN#2 and EAS#1 are the same satellite, meaning they are deployed on the same satellite). Thus, RAN#2 can communicate with EAS#1.

[0315] The third satellite (e.g., RAN#2 satellite) can be used to replace the second satellite (e.g., RAN#1 satellite) to provide access services for UE#1; in other words, the third satellite can be the satellite that provides access services for UE (e.g., UE#1) after UE (e.g., UE#1) is redirected; in other words, the third satellite can be the satellite deployed by the RAN (e.g., RAN#2) that serves UE (e.g., UE#1) after UE (e.g., UE#1) is redirected; in other words, the third satellite can be the satellite that provides access services for UE (e.g., UE#1) after UE (e.g., UE#1) is switched over; in other words, the third satellite can be the satellite deployed by the RAN (e.g., RAN#2) that serves UE (e.g., UE#1) after UE (e.g., UE#1) is switched over; in other words, the third satellite can be the satellite deployed by the target RAN (e.g., RAN#2) of UE (e.g., UE#1).

[0316] In some possible implementations, S560, including S564, involves the SMF sending second information to the AMF. This allows the AMF to determine the third satellite based on the second information.

[0317] Optionally, the second information includes information about the first satellite (e.g., EAS#1 satellite). This information about the first satellite can be used to identify satellites connected to the first satellite (e.g., a third satellite, such as RAN#2 satellite).

[0318] In this way, the AMF can determine the third satellite based on the information from the first satellite, and there is a connection between the third satellite and the first satellite.

[0319] Furthermore, in some possible implementations, the AMF can redirect UE#1, instructing UE#1 to switch to a third satellite; in other words, instructing UE#1 to access a third satellite. Specific examples can be found later, and will not be elaborated here.

[0320] Based on the above scheme, if there is no connection between the first satellite where the first application server (e.g., EAS#1) is located and the satellite (i.e., the second satellite) that the first terminal (e.g., UE#1) accesses, the SMF can determine a third satellite that is connected to the first satellite, thereby enabling the first terminal to access the third satellite and access the first application server on the satellite through the third satellite, so that the first terminal can access services.

[0321] The following section, referring to Figure 5, continues with Information Example 1. In Information Example 1, the second information can be used to determine AS#2, thereby enabling UE#1 to access the network through RAN#1 on the satellite and access AS#2.

[0322] In some possible implementations, the method 500 also includes: SMF configuring the UE#1 to access AS#2 through the anchor user plane network element.

[0323] Optionally, the SMF obtains the address information of the second application server (e.g., AS#2). In this way, the SMF can configure UE#1 to access AS#2 through the anchor user plane network element based on the address information of AS#2.

[0324] Among them, the anchor point user plane network element can be deployed on the ground or connected to the ground.

[0325] The anchor point user plane network element can be referred to as PSA, PSA UPF, C-PSA, or C-PSA UPF. In other words, the SMF may not configure a shunt point UPF (e.g., UL-CL and / or BP) and / or L-PSA. Alternatively, the SMF may not perform the actions of selecting and / or configuring the shunt point UPF and / or L-PSA.

[0326] In this way, UE#1 can access AS#2 deployed on the ground through only one anchor user plane network element (e.g., PSA) configured by SMF, without going through other UPFs.

[0327] Based on the above scheme, SMF can configure the first terminal to access the second application server through the anchor user plane network element without going through an additional user plane network element, thereby reducing the latency of the first terminal accessing the second application server in the NTN scenario.

[0328] When the above scheme is applied to the traditional EAS discovery process, after receiving the DNS response message, EASDF can indicate the address information of the EAS to SMF (for example, see S370 in Figure 3).

[0329] The DNS response message may also be called a response message, reply message, DNS reply message, notification message, DNS notification message, or other names, and this application does not limit it.

[0330] In some possible implementations, the EASDF still indicates the aforementioned address information (e.g., the address information of AS#2) to the SMF. However, the SMF may not configure the routing point based on this address information (e.g., not execute S374 in Figure 3), or the SMF may configure the UE#1 to access AS#2 through the anchor user plane network element.

[0331] In some other possible implementations, the method also includes: S570.

[0332] S570, the SMF sends third information to the EASDF. This third information can be used to instruct the EASDF not to send distribution point configuration information to the SMF. Correspondingly, the EASDF receives the third information from the SMF.

[0333] The routing point configuration information may include information about the servers deployed on the ground (e.g., address information), and / or information about the first service (e.g., FQDN#1).

[0334] Alternatively, when S570 is implemented, SMF does not need to be configured with a separate branch point, and UE#1 can access AS#2 through the default UPF (or PSA).

[0335] Based on the above scheme, EASDF can avoid sending traffic splitting point configuration information to SMF, saving transmission overhead. Furthermore, SMF does not need to configure traffic splitting points. On the one hand, this avoids the signaling overhead associated with configuring traffic splitting points; on the other hand, the first terminal accesses the second application server through the anchor user plane network element, without needing to go through additional user plane network elements, thereby reducing the latency of the first terminal accessing the second application server in NTN scenarios.

[0336] In some possible implementation scenarios, the SMF has not previously configured UE#1 to access AS#2 through the anchor user plane network element. The SMF may not execute S570. In this case, the EASDF can send the address information of AS#2 to the SMF based on the traditional EAS discovery procedure (or, the SMF can obtain the address information of AS#2), thereby configuring UE#1 to access AS#2 through the anchor user plane network element.

[0337] In some other possible implementation scenarios, the SMF has previously configured UE#1 to access AS#2 through the anchor user plane network element. The SMF can execute S570, that is, instruct the EASDF not to return information related to the offloading point configuration. The SMF does not need to configure the offloading point separately.

[0338] In some possible implementations, method 500 further includes: the SMF sending information A to the EASDF, information A being used to instruct the second network element to send a DNS response message to UE#1. Correspondingly, the EASDF receives information A from the SMF.

[0339] In some possible implementations, EASDF can respond to information A by sending a DNS response message to UE#1, which may include information about AS#2 (e.g., address information). In this way, UE#1 can access AS#2 through the newly configured anchor user plane network element of the SMF or the default anchor user plane network element.

[0340] In some other possible implementations, if the SMF sends third information to the EASDF, the EASDF can directly send the DNS response message to UE#1 without sending the relevant information indicated by the third information to the SMF.

[0341] The following is an example of determining that there is no connection between the first satellite (e.g., EAS#1 satellite) and the second satellite (e.g., RAN#1 satellite).

[0342] In some examples, the SMF can determine, based on ephemeris information, that there is no connection between the first and second satellites.

[0343] The following are examples of ephemeris information.

[0344] For example, ephemeris information can be used to indicate the position and / or coverage of a satellite. For instance, this ephemeris information can be information about the satellite's motion patterns, such as orbital parameters, angular velocity, and speed. Communication equipment, components, or functions (e.g., SMF) can use this information to calculate the satellite's position in orbit at each moment. Ephemeris information can be represented as a simple correspondence, such as satellite position information corresponding to each moment and / or time period. Ephemeris information can also be represented as a satellite coverage map, such as satellite coverage availability information. A satellite coverage map can divide the Earth's surface into multiple grid points and show the grid points covered and uncovered by the satellite at each moment. For example, a satellite's orbital period around the Earth is one hour, with an accuracy of minutes. Each minute, the satellite corresponds to a satellite coverage map, where some grid points are lit and some are dark. The lit grid points represent the grid points that the satellite will cover at that corresponding moment in each orbital period.

[0345] The ephemeris information involved in this application includes, but is not limited to, traditional ephemeris information, satellite map information, and gateway deployment information. For example, traditional ephemeris information includes, but is not limited to, orbital parameters, or parameters such as the satellite's azimuth calculated based on orbital parameters. It is understood that traditional ephemeris information can be used to calculate, predict, depict, or track the satellite's flight time, position, or velocity. For example, traditional ephemeris information can be 17 bytes of information to represent position (78 bits) and velocity (54 bits), or traditional ephemeris information can be 18 bytes of information to represent orbital parameters (e.g., semi-major axis, range, eccentricity, or perigee distance). Satellite map information can be the area covered by the satellite on a map at each moment. This application does not limit the specific form, content, and name of the ephemeris information; reference can be made to the definition of ephemeris information in the relevant protocol. For example, in this application, ephemeris information can also be referred to as satellite coverage availability information.

[0346] Optionally, the ephemeris information of this application may also include equipment information deployed on the satellite, such as whether an application server (e.g., EAS), access network equipment (e.g., next-generation RAN (NG-RAN)), or core network function (e.g., UPF) is deployed on the satellite. Optionally, the ephemeris information of this application may also include service information corresponding to the equipment deployed on the satellite, such as the services provided by the application server deployed on the satellite (e.g., one or more FQDNs corresponding to EAS, one or more DNNs corresponding to EAS), or the services that the access network equipment and core network equipment on the satellite can provide (e.g., one or more network slices corresponding to RAN and UPF, one or more DNNs corresponding to UPF). The network slice may correspond to single network slice selection assistance information (S-NSSAI) or other information.

[0347] Ephemeris information can be used to determine the movement trajectory of satellites, or the connectivity between satellites, etc. For example, ephemeris information may include the inter-satellite link connectivity between the satellites deployed by EAS#1 (e.g., the first satellite) and other satellites at each moment.

[0348] For example, ephemeris information can be stored locally by the SMF or obtained by the SMF from other network elements; this application does not limit this. For instance, it can be obtained from a core network element used to maintain ephemeris information or from equipment outside the core network, or from other core network elements, such as the AMF, in which case the AMF stores the ephemeris information. When the SMF obtains ephemeris information, it can do so directly or indirectly through one or more intermediate devices; this application does not limit this. The other network elements from which the SMF obtains ephemeris information can be referred to as fourth network elements.

[0349] Unless otherwise specified, the fourth network element in this application can be the device itself capable of implementing ephemeris maintenance functions, a component within that device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the ephemeris maintenance functions. For ease of description, the following description uses ephemeris maintenance function #1 as an example. This name is for descriptive convenience only and does not limit the name of this network element.

[0350] In other examples, the SMF can determine, based on indications from other network elements, that there is no connection between the first and second satellites. These "other network elements" can be core network elements or not.

[0351] In some possible implementations, prior to S560, the method 500 also includes S550.

[0352] S550, the SMF receives a fourth message from ephemeris maintenance function #1, indicating that there is no connection between the first satellite and the second satellite. Correspondingly, ephemeris maintenance function #1 sends the fourth message to the SMF.

[0353] This application does not limit the form of the fourth information. For example, the fourth information can be a 1-bit indication, where a value of 0 indicates that there is no connection between the first satellite and the second satellite, and a value of 1 indicates that there is a connection between the first satellite and the second satellite; or, a value of 1 indicates that there is no connection between the first satellite and the second satellite, and a value of 0 indicates that there is a connection between the first satellite and the second satellite. As another example, the fourth information may include information about the first satellite indicating that there is no connection between the first satellite and the second satellite.

[0354] Based on the above scheme, the SMF can determine that there is no connection between the first satellite and the second satellite based on indications from other network elements. In this scheme, the processing overhead of the SMF in determining that there is no connection between the first and second satellites is relatively small. For example, compared to the SMF's calculation based on ephemeris information, the above scheme only needs to identify the indication of the fourth information, resulting in lower processing overhead.

[0355] In some possible implementations, prior to S560, the method 500 also includes S540.

[0356] S540, the SMF sends a fifth message to the ephemeris maintenance function #1, which is used to query whether a connection exists between the first satellite and the second satellite. Correspondingly, the ephemeris maintenance function #1 receives the fifth message from the SMF.

[0357] As an example, in response to the fifth message, the ephemeris maintenance function #1 can determine whether there is a connection between the first satellite and the second satellite, and if there is a connection, send the aforementioned fourth message to the SMF.

[0358] The function of the fifth information can also be described as: requesting an indication of whether there is a connection between the first satellite and the second satellite, or subscribing to an indication of whether there is a connection between the first satellite and the second satellite, or other similar descriptions, which are not limited in this application.

[0359] Based on the above scheme, SMF can send information to the fourth network element to query whether there is a connection between the first satellite and the second satellite, thereby reducing the processing overhead caused by the absence of a connection between the first satellite and the second satellite.

[0360] Optionally, the fifth information includes at least one of the information of the first application server (e.g., EAS#1), the information of the first satellite (e.g., EAS#1 satellite), or the information of the second satellite (e.g., RAN#1 satellite).

[0361] For example, the above information may be an identifier, address information, or other information that can represent the first application server, the first satellite, or the second satellite.

[0362] For example, the SMF determines that the first application server is deployed on the first satellite based on the locally stored mapping between application servers and satellites, and the AMF instructs the SMF to allow the first terminal to access the second satellite. The mapping between application servers and satellites stored locally by the SMF can be EAS deployment information and / or DNAI mapping between satellites.

[0363] Optionally, when the fifth information includes information about the first application server, before the ephemeris maintenance function sends the fourth information to the SMF, it also includes: the ephemeris maintenance function determining that the first application server is deployed on the first satellite.

[0364] For example, the ephemeris maintenance function determines the deployment of the first application server on the first satellite based on the correspondence between the application server and the satellite stored locally.

[0365] In some examples, the fifth piece of information may include information about the first satellite (e.g., EAS#1 satellite) and / or information about the second satellite (e.g., RAN#1 satellite).

[0366] Further, optionally, prior to S540, method 500 further includes: the SMF determining that EAS#1 is deployed on the first satellite (e.g., EAS#1 satellite); and the SMF determining that UE#1 accesses the second satellite (e.g., RAN#1 satellite).

[0367] For example, the SMF can determine that EAS#1 is deployed on the first satellite based on the locally stored mapping between application servers and satellites. The mapping between application servers and satellites stored locally by the SMF can be EAS deployment information and / or the mapping between data network access identifiers (DNAIs) and satellites. The AMF can instruct the SMF to allow UE#1 to access the second satellite.

[0368] The information in the information of the first satellite or the second satellite that is not carried in the fifth information may be information known to the ephemeris maintenance function #1. For example, when the ephemeris maintenance function #1 is an AMF, the ephemeris maintenance function #1 knows the information of the second satellite, and the fifth information may only include the information of the first satellite.

[0369] In this way, the ephemeris maintenance function #1 can determine whether there is a connection between the first satellite and the second satellite based on the information of the first satellite and the information of the second satellite, combined with the ephemeris information stored in the ephemeris maintenance function #1.

[0370] In some possible implementations, prior to S540 above, method 500 further includes: the SMF receiving information about the first satellite from ephemeris maintenance function #2. Correspondingly, ephemeris maintenance function #2 sends information about the first satellite to the SMF.

[0371] In this way, SMF can obtain information about the first satellite and thus carry that information in the fifth message.

[0372] Among them, the ephemeris maintenance function #2 can be the device itself that can implement the ephemeris maintenance function, or a component in the device (e.g., a processor, chip, or chip system), or a logic module or software that can implement all or part of the ephemeris maintenance function.

[0373] In some possible implementations, before the SMF sends the fifth information to the ephemeris maintenance function #2, the method 500 further includes: the SMF sending information B to the ephemeris maintenance function #2, which is used to query information about the first satellite. Correspondingly, the ephemeris maintenance function #2 receives information B from the SMF.

[0374] Information B can be used to query information about the first satellite; in other words, information B is used to request information about the first satellite; in other words, information B is used to request ephemeris maintenance function #2 to provide (or send) information about the first satellite; in other words, information B can be used to subscribe to information about the first satellite.

[0375] Optionally, the information B includes information about the first application server (e.g., EAS#1).

[0376] The ephemeris maintenance function #2 and the ephemeris maintenance function #1 may be the same or different; this application does not impose any restrictions.

[0377] When ephemeris maintenance function #2 is the same as ephemeris maintenance function #1, the descriptions of ephemeris maintenance function #2 and ephemeris maintenance function #1 in this application embodiment are interchangeable and not distinguished.

[0378] When ephemeris maintenance function #2 differs from ephemeris maintenance function #1, ephemeris maintenance function #2 and ephemeris maintenance function #1 can respectively provide the SMF with information about the first satellite and fourth information (indicating that there is no connection between the first satellite and the second satellite). For example, ephemeris maintenance function #2 can maintain information about each satellite and the servers or network elements deployed on it, while ephemeris maintenance function #1 can maintain information about whether there is a connection between satellites. Thus, ephemeris maintenance function #2 can provide the SMF with satellite information, and ephemeris maintenance function #1 can indicate to the SMF whether there is a connection between satellites.

[0379] In other examples, the fifth piece of information may include information about the first application server (e.g., EAS#1 satellite) and / or information about the second satellite (e.g., RAN#1 satellite).

[0380] Among these, the information in the information of the first application server or the information of the second satellite that is not carried by the fifth information can be information known to the ephemeris maintenance function #1. For example, if the ephemeris maintenance function #1 knows the information of the first application server, the fifth information may only include the information in the second information.

[0381] As an example, ephemeris maintenance function #1 can determine, based on information from the first application server, that the first application server is deployed on the first satellite. Furthermore, ephemeris maintenance function #1 can combine ephemeris information to determine whether a connection exists between the first satellite and the second satellite.

[0382] As another example, ephemeris maintenance function #1 can determine whether there is a connection between the satellite deployed by the first application server (i.e., the first satellite) and the second satellite based on the mapping relationship between the first application server and the second satellite.

[0383] The following is an example of SMF-assisted discovery of EAS#1.

[0384] In S530 above, EASDF sends information (i.e., first information) to SMF indicating the first application server (e.g., EAS#1) deployed on the satellite. An example of SMF assisting EASDF in discovering the application server deployed on the satellite is described below.

[0385] In some possible implementations, prior to S530, the method 500 also includes S520.

[0386] S520, the SMF sends a second address information to the EASDF, which is used to identify the application server (e.g., EAS#1) deployed on the satellite.

[0387] For example, the second address information could be the address information of a network element deployed on the satellite (e.g., a UPF). In this way, EASDF can generate an ECS option based on the second address information, and the content of the ECS option field can be the second address information. EASDF can then send a DNS request message with the added ECS option to a DNS server, which can determine the application server (e.g., EAS#1 deployed on the satellite) with a high IP affinity to the second address information included in the ECS option.

[0388] The DNS request message may also be called a request message, query message, DNS query message, subscription message, DNS subscription message, or other names, which are not limited in this application.

[0389] Based on the above scheme, SMF can send a second address information to EASDF to help discover application servers deployed on satellites.

[0390] Optionally, the second address information is used to determine the application server that has a connection with the satellite accessed by UE#1. For example, the second address information may be the address information of a UPF deployed on the satellite accessed by UE#1 (e.g., a second satellite or other satellites). As another example, the second address information may be the address information of a UPF deployed on a satellite connected to the satellite accessed by UE#1.

[0391] The second address information can also be the address information of other network elements, not limited to UPF.

[0392] According to the above scheme, the application server discovered by EASDF through the DNS server can have a connection with the satellite accessed by UE#1, thereby enabling UE#1 to access the application server.

[0393] It is understandable that during the execution of S520 by the SMF, or for a period of time before or after that moment, the satellite accessed by UE#1 and the application server determined by the second address information may be connected. However, as the satellites move, the satellites accessed by UE#1 may change, and the connection status between the satellites accessed by UE#1 and the application server determined by the second address information may also change. Therefore, the above scheme can enable UE#1 to access the application server determined by the second address information (e.g., EAS#1) for a certain period of time, but after the aforementioned period of time, UE#1 may not be able to access the application server determined by the second address information. Alternatively, because the local logic of the DNS server does not consider the connection status of the inter-satellite links between satellites, the inter-satellite link between the satellite deployed by the application server replied by the DNS server and the satellite accessed by UE#1 is disconnected when the UE or EASDF receives the DNS reply message, thus executing S560 and related schemes.

[0394] In some possible implementations, method 500 also includes: S510.

[0395] S510, SMF obtains information about the first service.

[0396] As an example, SMF can obtain information about the first service (e.g., FQDN#1) from EASDF.

[0397] For example, if the EASDF obtains a DNS query message from the UE, which includes information about the first service, then the EASDF sends the information about the first service to the SMF.

[0398] In some possible implementations, S520 includes: if the server corresponding to the first service is deployed on a satellite, the SMF sends the second address information to the EASDF.

[0399] In the case where the first service corresponds to multiple servers, the servers corresponding to the first service are deployed on satellites. This can be understood as some of the servers corresponding to the first service being deployed on satellites (while other servers may not be deployed on satellites).

[0400] In some other possible implementations, where the server corresponding to the first service is deployed on the ground, the SMF does not send the second address information to the EASDF.

[0401] In the case where the first service corresponds to multiple servers, the servers corresponding to the first service are deployed on the ground. This can be understood as all servers corresponding to the first service being deployed on the ground.

[0402] As an example, the SMF can determine whether a first service is deployed on a satellite. For instance, the SMF can pre-obtain information about services deployed on the satellite (e.g., in the form of an FQDN list, or in the form of EAS deployment information). The SMF can then determine whether the information for the first service falls within the scope of the aforementioned service information.

[0403] If the information of the first service is within the scope of the aforementioned service information, then the SMF can send the second address information to the EASDF.

[0404] If the information for the first service falls within the scope of the aforementioned service information, the SMF may choose not to send any address information to the EASDF (or instruct the EASDF not to add the ECS option), or it may send the address information of the terrestrial network element (e.g., UPF) to the EASDF. In this way, the EASDF can discover the application server deployed on the terrestrial surface.

[0405] Based on the above scheme, SMF can use the second address information to help discover the application server deployed on the satellite when the server corresponding to the first service is deployed on the satellite, thus avoiding the discovery of the application server deployed on the satellite when there is no service deployed on the satellite, thereby enhancing the availability of UE#1 accessing the service.

[0406] Figure 6 is a schematic flowchart of another communication method 600 provided in an embodiment of this application. Method 600 can be used as a specific example of information example 1 of method 500. In the absence of a connection between the first satellite where the first application server (e.g., EAS#1) is located and the satellite accessed by the first terminal (e.g., UE#1) (i.e., the second satellite), method 600 can cause UE#1 to fall back to accessing the application server on the ground (e.g., AS#2), thereby enabling UE#1 to access services normally. Optional operations in method 600 are shown in dashed lines in Figure 6. The various operations of method 600 are described below with reference to Figure 6.

[0407] S602, the AMF sends the identifier of the satellite (e.g., RAN#1 satellite) accessed by UE#1 to the SMF. Correspondingly, the SMF receives the identifier of the satellite accessed by UE from the AMF.

[0408] The execution order of S602 described above can be after other operations in method 600, and this application does not impose any restrictions.

[0409] For example, S602 can be executed after the PDU session is established or during the PDU session establishment process.

[0410] Optionally, the identifier of the satellite accessed by UE#1 (e.g., RAN#1 satellite) is carried in the request message, for example, in the message Nsmf_PDUSession_CreateSMContext_Request(Nsmf_PDU session_createSM context_request). Here, Nsmf can be the service interface of SMF.

[0411] In some possible implementations, the SMF can determine whether UE#1 accesses via a satellite based on the identifier of the satellite accessed by UE#1 (e.g., RAN#1 satellite), and / or whether there is a connection between the satellite accessed by UE#1 and the satellite where the subsequently discovered EAS is located.

[0412] S604, SMF acquires service information deployed on the satellite. S604 is an optional operation.

[0413] For example, the above business information can be in the form of an FQDN list.

[0414] Optionally, the aforementioned business information is carried in a deployment notification message, for example, in the message Nnef_EASDeployment_Notify(Nnef_EAS deployment_notification). Here, Nnef can be a NEF service interface.

[0415] In some possible implementations, SMF can use the traditional EAS deployment information acquisition process to obtain the aforementioned business information from NEF.

[0416] S610, UE#1 sends a DNS request message to EASDF. Correspondingly, EASDF receives the DNS request message from UE#1.

[0417] For details, please refer to the description in S320, which will not be repeated here.

[0418] S620, EASDF sends an indication of the FQDN to SMF. Correspondingly, SMF receives the indication of the FQDN from EASDF. This indication may specify the FQDN (e.g., FQDN#1) included in the DNS request message.

[0419] Optionally, the aforementioned indication information is carried in a notification message, for example, in the message Neasdf_DNSContext_Notify(Neasdf_DNSContext_Notification). Here, Neasdf can be an EASDF service interface.

[0420] In some possible implementations prior to S620, EASDF could match DNS processing rules, as described in method 300, and will not be repeated here.

[0421] In S630, the SMF determines whether the service corresponding to the FQDN is deployed on the satellite. S630 is an optional operation.

[0422] As an example, after receiving the indication information for FQDN#1, the SMF can determine whether the service corresponding to FQDN#1 is deployed on the satellite. For instance, based on the service information obtained in S604, it can be determined whether the service corresponding to FQDN#1 is deployed on the satellite.

[0423] If the service corresponding to FQDN#1 is deployed on a satellite, the SMF can determine the address information in the ECS option based on the satellite accessed by UE#1. For example, this address information can indicate the UPF address deployed on the satellite accessed by UE#1, or the address of the UPF deployed on a satellite that has an inter-satellite link with the satellite accessed by UE#1.

[0424] If the service corresponding to FQDN#1 is not deployed on the satellite, the SMF may either not specify the address information (or not instruct the EASDF to add the ECS option), or specify the address information in the ECS option as a UPF address on the ground.

[0425] In some possible implementations, method 600 also includes S510 before S630, as detailed above, and will not be repeated here.

[0426] S632, the SMF sends the second address information to the EASDF. Correspondingly, the EASDF receives the address information from the SMF.

[0427] Optionally, the aforementioned second address information is carried in an update message, for example, in the message Neasdf_DNSContext_Update(Neasdf_DNSContext_Update). Here, Neasdf can be an EASDF service interface.

[0428] For a detailed description of the second address information, please refer to the aforementioned S520, which will not be repeated here.

[0429] Other descriptions of S632 above can be found in the example of S345, and will not be repeated here.

[0430] S634, EASDF sends a DNS request message to the DNS server. Correspondingly, the DNS server receives the DNS request message from EASDF.

[0431] Optionally, the ECS option field in S634 may contain address information (e.g., second address information) provided by the SMF to the EASDF in S345.

[0432] Other descriptions of S634 above can be found in the example of S350, and will not be repeated here.

[0433] S636, the DNS server sends a DNS response message to EASDF. Correspondingly, EASDF receives the DNS response message from the DNS server.

[0434] The DNS response message may include FQDN#1 and the address information of EAS (e.g., EAS#1).

[0435] For further descriptions of S636 above, please refer to the example in S355, which will not be repeated here.

[0436] S638, EASDF sends the first message to SMF. Correspondingly, SMF receives the first message from EASDF.

[0437] The first piece of information can be used to indicate the first application server (e.g., EAS#1).

[0438] Optionally, the aforementioned first information is carried in a notification message, for example, in the message Neasdf_DNSContext_Notify(Neasdf_DNSContext_Notification). Here, Neasdf can be an EASDF service interface.

[0439] Other descriptions of S638 above can be found in the relevant examples of S370 and S530, which will not be repeated here.

[0440] In some possible implementations, prior to S638, EASDF can match DNS processing rules, as described in method 300, which will not be repeated here.

[0441] S640, SMF determined that there is no connection between EAS#1 satellite and RAN#1 satellite.

[0442] For example, the SMF can determine, based on ephemeris information, that there is no connection between the EAS#1 satellite and the RAN#1 satellite.

[0443] For example, SMF can execute the aforementioned S540 and S550 to determine that there is no connection between EAS#1 satellite and RAN#1 satellite. See S540 and S550 for details, which will not be repeated here.

[0444] S650, the SMF sends second information to the EASDF. This second information can be used to identify a second application server (e.g., AS#2). Correspondingly, the EASDF receives the second information from the SMF. For example, the second information may include first address information.

[0445] The S650 above can also be understood as the SMF instructing the EASDF to re-initiate the DNS query and to indicate a new ECS option. This ECS option can be used to indicate the address of the application server for discovering the ground (for example, the address information in the ECS option indicates the address of a ground UPF).

[0446] Optionally, the aforementioned second information is carried in an update message, for example, in the message Neasdf_DNSContext_Update(Neasdf_DNSContext_Update). Here, Neasdf can be an EASDF service interface.

[0447] For further descriptions of the second information, please refer to the examples above, such as the example in S562, which will not be repeated here.

[0448] In some possible implementations, the SMF can also send third information to the EASDF to instruct the EASDF not to send information related to the distribution point configuration. Alternatively, the third information can be understood as instructing the DNS response message corresponding to this FQDN#1 not to be reported to the SMF.

[0449] The third message can be carried in the same message as the second message. In other words, the SMF can send both the second and third messages to the EASDF from the S650. Further descriptions of the third message can be found in the examples above, such as the S570 example, and will not be repeated here.

[0450] S652, EASDF sends a new DNS request message to the DNS server. Correspondingly, the DNS server receives the new DNS request message from EASDF.

[0451] The difference between the new DNS request message mentioned above and the DNS request message in S634 is at least that the ECS option of the new DNS request message in S652 is the first address information sent by the SMF in S650.

[0452] The naming of the new DNS request message is solely for the purpose of distinguishing it from other DNS request messages in the embodiments of this application. The new DNS request message may also have other names, which are not limited in this application.

[0453] Other descriptions of S652 above can be found in the example of S350, and will not be repeated here.

[0454] S654, The DNS server sends a DNS response message to EASDF. Correspondingly, EASDF receives a DNS response message from the DNS server.

[0455] The DNS response message may include the address information of FQDN#1 and AS (e.g., AS#2).

[0456] For further details on S654 above, please refer to the example in S355; further details will not be repeated here.

[0457] S656, EASDF sends the address information of the second application server (e.g., AS#2) to SMF. Correspondingly, SMF receives the address information of the second application server from EASDF.

[0458] For example, the aforementioned address information can be carried in a notification message, such as the Neasdf_DNSContext_Notify(Neasdf_DNSContext_Notification) message. Here, Neasdf can be an EASDF service interface.

[0459] Other descriptions of S656 above can be found in the relevant examples of S370, and will not be repeated here.

[0460] In some possible implementations prior to S656, EASDF could match DNS processing rules, as described in method 300, and will not be repeated here.

[0461] S660, SMF configures the user plane to access the second application server (e.g., AS#2) via PSA.

[0462] For example, the SMF can be configured for UE#1 to access the first service on AS#2 (e.g., the service corresponding to FQDN#1) via PSA. As an example, the SMF may not configure a splitter point UPF. In this way, UE#1 can directly access the first service on AS#2 via PSA, without going through other UPFs.

[0463] S670, the SMF sends information A to the EASDF. Information A instructs the EASDF to send a DNS response message to UE#1. Correspondingly, the EASDF receives information A from the SMF.

[0464] Optionally, the aforementioned information A is carried in an update message, for example, in the message Neasdf_DNSContext_Update(Neasdf_DNSContext_Update). Here, Neasdf can be an EASDF service interface.

[0465] The above-mentioned operations S656, S660, and S670 are optional. For example, if the SMF sends third information to the EASDF (i.e., performs S570), the above-mentioned operations S656, S660, and S670 may not be performed.

[0466] S680, EASDF sends a DNS response message to UE#1. Correspondingly, UE#1 receives a DNS response message from EASDF.

[0467] The DNS response message may include the address information of the second application server (e.g., AS#2).

[0468] Based on the above scheme, SMF can determine that there is no inter-satellite link between EAS#1 in the DNS response message and the satellite accessed by UE#1, and configure UE#1 to fall back to AS#2 to access the ground, thereby ensuring that UE#1 can access services normally.

[0469] Next, referring to Figure 5, we will continue to introduce information example 2.

[0470] In information example 2, this second information can be used to determine a third satellite. The third satellite (e.g., RAN#2 satellite) can be used to provide access service to UE#1 in place of the second satellite (e.g., RAN#1 satellite). Thus, by redirecting UE#1 to RAN#2 satellite, UE#1 can access EAS#1 satellite and obtain the first service.

[0471] Referring to Figure 5, in S560, the SMF can send second information to the AMF, which can be used to identify the RAN#2 satellite. Optionally, the second information includes information about the first satellite (e.g., the EAS#1 satellite), enabling the AMF to identify a satellite (e.g., the RAN#2 satellite) that has a connection with the first satellite, thereby providing access services to UE#1.

[0472] Optionally, the second information may also include first indication information, which is used to indicate that the UE#1 should be redirected.

[0473] The first indication information can indicate that UE#1 should be redirected. Thus, the AMF can determine, based on the first indication information, that UE#1 should be redirected, and based on the information of the first satellite, determine the satellite with which a connection exists and which can provide access services to UE#1 (e.g., RAN#2 satellite).

[0474] In some possible implementations, method 500 further includes: the AMF sending a sixth message to a second satellite (e.g., RAN#1 satellite). This sixth message can be used to instruct the UE#1 to be redirected to the third satellite (e.g., RAN#2 satellite).

[0475] For example, the sixth information may include the radio access technology (RAT) or frequency selection priority (RFSP) index of the access network equipment (e.g., RAN#2) on the third satellite. Thus, the second satellite (e.g., RAN#1) can redirect UE#1 to RAN#2 based on the aforementioned RFSP index of RAN#2.

[0476] There is a connection between the third satellite (e.g., RAN#2 satellite) and the first satellite (e.g., EAS#1 satellite). The first satellite is equipped with a first application server (e.g., EAS#1), which is used to provide a first service (e.g., the service corresponding to FQDN#1) for the UE#1.

[0477] In some possible implementations, the method 500 further includes: the AMF determining the third satellite based on the second information, the third satellite having a connection with the first satellite, and the third satellite having access network equipment (e.g., RAN#2) deployed on it.

[0478] RAN#2 can be a RAN device, a component within a RAN device, or a functional module capable of enabling access; this application does not impose any limitations on this.

[0479] In some possible implementations, the method 500 further includes: the AMF acquiring ephemeris information; and the AMF determining the third satellite based on the second information and the ephemeris information.

[0480] For example, the AMF can configure ephemeris information locally. This ephemeris information can include the mapping between satellite identifiers (UD) and access network equipment (e.g., RAN) information. The RAN information can be the RAN identifier, or the cell, TA, or other information corresponding to the RAN.

[0481] In some other possible implementations, the AMF can obtain information (e.g., identification) of at least one satellite that has a connection with the first satellite (e.g., EAS#1 satellite) from the ephemeris maintenance function #1. Further, the AMF can identify, from the information of the at least one satellite, a satellite capable of providing access services to UE#1 as a third satellite (e.g., RAN#2 satellite).

[0482] In Information Example 2, an example of determining that there is no connection between the first satellite (e.g., EAS#1 satellite) and the second satellite (e.g., RAN#1 satellite) can be found in the preceding text (e.g., the relevant content in Information Example 1), and will not be repeated here.

[0483] In Message Example 2, an example of SMF-assisted discovery of EAS#1 can be found in the preceding text (e.g., the relevant content in Message Example 1), and will not be repeated here.

[0484] Figure 7 is a schematic flowchart of another communication method 700 provided in this application embodiment. Method 700 can be used as a specific example of information example 2 of method 500. When there is no connection between the first satellite where the first application server (e.g., EAS#1) is located and the satellite accessed by the first terminal (e.g., UE#1) (i.e., the second satellite, e.g., RAN#1 satellite), method 600 can enable UE#1 to switch to a satellite connected to the satellite where EAS#1 is located (e.g., RAN#2 satellite), thereby enabling UE#1 to access services normally. Optional operations in method 700 are shown in dashed lines in Figure 7. The various operations of method 700 are described below with reference to Figure 7.

[0485] Method 700 may include any one of S602, S604, S610, S620, S630, S632, S634, S636, or S638. In other words, method 700 may include any operation of method 600 before S640, which will not be described in detail here.

[0486] Method 700 may include S640.

[0487] S640, SMF determined that there is no connection between EAS#1 satellite and RAN#1 satellite.

[0488] For details of S640 above, please refer to the previous text, such as the relevant description in method 600, which will not be repeated here.

[0489] S710, the SMF sends a second message to the AMF. This second message is used to identify a third satellite (e.g., RAN#2 satellite). Correspondingly, the AMF receives the second message from the SMF.

[0490] For example, the second information may include information about the first satellite (e.g., EAS#1 satellite). This allows the AMF to determine which satellite (e.g., a third satellite) has a connection with the first satellite. Optionally, the second information may also include first indication information. The first indication information may indicate to the AMF to redirect UE#1.

[0491] Optionally, the aforementioned second information is carried in a transmission message, for example, in the message Namf_Communication_N1N2MessageTransfer. Here, Namf can be the service interface of the AMF. N1 can be the interface between the AMF and the UE. N2 can be the interface between the AMF and the access network equipment.

[0492] For further descriptions of the second information, please refer to the examples above, such as the example in S564, which will not be repeated here.

[0493] S720, AMF identifies a third satellite (e.g., RAN#2) that has a connection to EAS#1 satellite.

[0494] For example, the AMF can determine a third satellite with a connection to the EAS#1 satellite based on the second information sent by the SMF.

[0495] Other examples of S720 mentioned above can be found in the preceding text, such as the relevant content in Information Example 2, which will not be repeated here.

[0496] S730, the AMF sends a sixth message to the second satellite (e.g., RAN#1 satellite). This sixth message can be used to instruct the UE#1 to be redirected to the third satellite (e.g., RAN#2 satellite).

[0497] For example, the sixth information can be carried in the N2 message.

[0498] Other examples of S730 mentioned above can be found in the preceding text, such as the relevant content in Information Example 2, which will not be repeated here.

[0499] S740, the second satellite (e.g., RAN#1 satellite) redirects UE#1 to the third satellite (e.g., RAN#2 satellite).

[0500] The second satellite can also be referred to as the source satellite; the third satellite can also be referred to as the target satellite. RAN#1 can also be referred to as the source RAN, and RAN#2 can also be referred to as the target RAN; this application does not impose any restrictions.

[0501] After S740, UE#1 can connect to EAS#1 via a third satellite (e.g., RAN#2 satellite).

[0502] Based on the above scheme, SMF can determine that there is no inter-satellite link between EAS#1 in the DNS response message and the satellite accessed by UE#1 (e.g., RAN#1 satellite), and trigger the UE to switch to a satellite with an inter-satellite link to the satellite where EAS#1 is located (e.g., RAN#2 satellite), thereby ensuring that the UE can access services normally.

[0503] Figure 8 is a schematic flowchart of another communication method 800 provided in an embodiment of this application. Method 800 ensures a connection between the satellite where the application server is located (as resolved) and the satellite accessed by the terminal by selecting a dedicated DNS server, enabling the terminal to access services normally and improving communication availability. Optional operations in method 800 are shown in dashed lines in Figure 8. Exemplarily, method 800 can be applied to a satellite communication system (e.g., a regenerative satellite communication system). The various nodes involved in method 800 are described below.

[0504] Unless otherwise specified, the second terminal in this application may be the terminal device itself, a component within the terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the terminal device's functions. For ease of description, UE#2 will be used as an example below.

[0505] Unless otherwise specified, the first network element in this application can be the device itself capable of implementing session management functions, a component within that device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the session management functions. For ease of description, the first network element will be used as an example below.

[0506] For example, the first network element can be used for session management and / or connection management. For instance, the first network element can be called a session management function (SMF) or other names; this application does not limit the specific name of the first network element. The first network element can be a network element (or a function within a network element) used for session management and / or connection management in a 5G communication system or a future communication system.

[0507] For ease of description and understanding, the following description will use SMF as an example.

[0508] Unless otherwise specified, the second network element in this application can be the device itself capable of discovering or selecting EAS, a component within that device (e.g., a processor, chip, or chip system), or a logical module or software capable of implementing all or part of the EAS discovery function. Examples include EASDF, UPF, DNS server, or other devices capable of collaboratively or independently performing EAS discovery; no limitation is made. For ease of description, EASDF will be used as an example below.

[0509] Unless otherwise specified, the first DNS server (also referred to as the first DNS resolver) in this application can be a server device, a component within a server device (e.g., a processor, chip, or chip system), a virtual machine, a container, or an instance, or a logical module or software capable of providing all or part of the DNS service functions. For ease of description, the following description uses the first DNS server as an example.

[0510] The following section, with reference to Figure 8, describes each operation in method 800.

[0511] S810, the SMF receives the seventh message from the EASDF, wherein the seventh message is used to indicate information about the second service. Correspondingly, the EASDF sends the seventh message to the SMF.

[0512] The seventh information in S810 described above can also come from other functions, such as UPF, DNS server, or other devices capable of cooperating or performing EAS discovery independently, and is not limited to EASDF. In other words, S810 described above can be replaced by SMF receiving the seventh information from other functions.

[0513] The second service is similar in meaning to the first service mentioned above, and will not be repeated here. The following description uses FQDN#2 as an example of the information for the second service.

[0514] The seventh piece of information can be direct indication information, such as FQDN#2. It can also be indirect indication information, such as the identifier corresponding to FQDN#2, like the application ID. In this way, the SMF can determine the FQDN#2 corresponding to the identifier based on the pre-stored correspondence between identifiers and FQDNs.

[0515] For example, the seventh piece of information can be carried in a DNS context notification message, such as a Neasdf_DNSContext_Notify message. The seventh piece of information can also be carried in other messages, which are not limited herein.

[0516] S820, the SMF sends the first DNS server information to the EASDF. Correspondingly, the EASDF receives the first DNS server information from the SMF.

[0517] For example, the information of the first DNS server may be address information, identification information, or other information corresponding to the first DNS server.

[0518] The aforementioned first DNS server may also be referred to as a specific DNS server, a local DNS server, a server, or other names, which are not limited in this application.

[0519] SMF can execute S820 above if certain conditions are met. For example, the conditions include at least one of the following:

[0520] UE#2 accesses the network via satellite.

[0521] This second service is deployed on satellites.

[0522] In some examples, the SMF can obtain information about whether UE#2 accesses the network via satellite. For example, the SMF can obtain the satellite identifier accessed by UE#2, or the SMF can obtain information about UE#2's access type / radio access type as satellite access. For example, the SMF can obtain the above information from the AMF.

[0523] In other examples, the SMF can obtain information about services deployed on the satellite (e.g., a list of FQDNs, EAS deployment information, etc.), for instance, the SMF can obtain this information from the NEF. If the FQDN range in the aforementioned service information includes FQDN#2, it is determined that the second service (i.e., the service corresponding to FQDN#2) is deployed on the satellite.

[0524] The fourth satellite provides access services for UE#2, which could be that UE#2 accesses the fourth satellite, or UE#2 accesses the access network equipment deployed on the fourth satellite, or the access network equipment deployed on the fourth satellite is used to provide access services for UE#2, or UE#2 accesses the network through the fourth satellite, or the fourth satellite is the satellite that UE#2 accesses.

[0525] As an example, the fourth satellite may be deployed with a RAN (denoted as RAN#3). Thus, RAN#3 can also be referred to as an on-board RAN.

[0526] RAN#1 can be an access network device, a component within the access network device (e.g., a processor, chip, or chip system), or a logic module or software that can implement all or part of the access functions.

[0527] UE#2 accesses the network through the fourth satellite, which can be understood as UE#2 accessing the network through RAN#3 on the fourth satellite; in other words, UE#2 accesses RAN#3 on the fourth satellite; in other words, RAN#3 on the fourth satellite can be used to provide access services for UE#2; in other words, RAN#3 on the fourth satellite can be the RAN that UE#2 accesses.

[0528] The fourth satellite can be a satellite deployed in RAN#3. For ease of understanding and description, the fourth satellite can be referred to as the RAN#3 satellite. The RAN#3 satellite can be deployed solely in RAN#3, or it can be deployed in conjunction with RAN#3 and other network elements (or other servers). This application does not impose any restrictions on this.

[0529] A connection can exist between the RAN#3 satellite and the third application server.

[0530] The third application server can be a server device, a component within the server device, a virtual machine, an instance, a container, or a logical module or software that provides all or part of the application service functions. For example, the third application server can be EAS or other servers.

[0531] For ease of description, the following description will use EAS as the third application server as an example, and we will refer to the third application server as EAS#3.

[0532] EAS#3 can be deployed on a satellite (denoted as EAS#3 satellite). Thus, EAS#3 can also be called an onboard EAS. The EAS#3 satellite can be used to deploy only EAS#3, or it can be used to deploy EAS#3 with other servers (or other network elements), which is not limited in this application.

[0533] Specifically, EAS#3 can be used to provide a second service to UE#2; or it can be understood as EAS#3 being used to provide the service of the second service to UE#2; or it can be understood as UE#2 being able to obtain the service of the second service by accessing EAS#3; or it can be understood as EAS#3 being used to enable UE#2 to access the second service; or it can be understood as EAS#3 being used for UE#2 to access the second service; or it can be understood as UE#2 being able to access EAS#3 to receive the second service; or it can be understood as UE#2 being able to access the second service through EAS#3; or it can be understood as the second service being deployed / configured on EAS#3; or it can be understood as UE#2 accessing (or accessing) the second service through EAS#3; or it can be understood as EAS#3 being used for UE#2 to access (or access) the second service.

[0534] It is understandable that while EAS#3 can be used to provide a second service to UE#2, this does not mean that EAS#3 will necessarily successfully provide the second service to UE#2. In other words, UE#2 may not be able to successfully access EAS#3, or access the second service through EAS#3. For example, EAS#3 may not be able to communicate with the satellite currently accessed by UE#2 (e.g., there is no inter-satellite link between the satellite deployed by EAS#3 and the satellite accessed by UE#2 during a certain period), thus failing to provide the second service to UE#2. However, those skilled in the art will understand that EAS#3 has the capability to provide a second service to UE#2, but may not necessarily succeed in providing the second service.

[0535] Optionally, the third application server (e.g., EAS#3) is deployed on the fifth satellite (e.g., EAS#3 satellite), and there is a connection (e.g., inter-satellite link) between the fifth satellite and the fourth satellite.

[0536] In some possible implementations, the SMF can obtain the information about the first DNS server from the NEF. This information may include the first DNS server's identifier, address information, or other information that identifies the first DNS server.

[0537] The first DNS server can be used to determine the third application server (e.g., EAS#3) that has a connection with the fourth satellite (e.g., RAN#3 satellite).

[0538] In some examples, the first DNS server may correspond to the network access point of UE#2. In this way, the first DNS server can determine the application server (e.g., EAS#3) that has a connection with the access satellite (e.g., RAN#3 satellite) corresponding to that network access point.

[0539] The network access point can be indicated by DNAI.

[0540] For example, the first DNS server can ensure that there is a connection between the access satellite of the UE accessing the first DNAI and the application server discovered by the first DNS server.

[0541] In other examples, method 300 also includes: S830.

[0542] S830, the SMF sends third address information to the EASDF. This third address information is used to indicate the fourth satellite, or to indicate a satellite connected to the fourth satellite.

[0543] Correspondingly, EASDF receives third address information from SMF.

[0544] The third address information and the information of the first DNS server can be carried in the same or different messages, and this application does not limit this.

[0545] For example, the third address information is the address information of the fourth network element, which is deployed on the fourth satellite, or there is a connection between the satellite on which the fourth network element is deployed and the fourth satellite.

[0546] For example, the fourth network element can be a UPF.

[0547] For example, EASDF includes the third address information as an ECS option in the DNS query message and sends the DNS query message to the first DNS server.

[0548] Optionally, the third address information is used by the first DNS server to determine a third application server that has a connection with the fourth satellite.

[0549] For example, the first DNS server has the capability to ensure connectivity between the determined application server (e.g., EAS#3) and the third address information. For instance, if the first DNS server is configured with ephemeris information and a mapping between the addresses of the application server and / or UPF (or other network elements) and satellites, then the first DNS server can determine the satellite corresponding to the address in the ECS option. Therefore, when determining the application server (e.g., EAS#3), it can identify a server deployed on a satellite connected to the satellite corresponding to the address in the ECS option. The third address information can be the fourth satellite (e.g., RAN#3) accessed by UE#2, or it can be a satellite connected to the fourth satellite (e.g., RAN#3). Thus, the application server (e.g., EAS#3) determined by the first DNS server can have a direct or indirect connection with the fourth satellite (e.g., RAN#3) accessed by UE#2, thereby ensuring that UE#2 can normally access the application server (e.g., EAS#3) through the fourth satellite.

[0550] Based on the above scheme, SMF can provide information about a first DNS server. This first DNS server can be used to determine the application server that has a connection with the satellite accessed by the terminal, thereby enabling the first terminal to access services.

[0551] In some possible implementations, the method 800 further includes: the SMF acquiring eighth information, which indicates at least one service deployed on the satellite; and the SMF determining, based on the eighth information, that the second service is deployed on the satellite and that the second service belongs to the aforementioned at least one service.

[0552] For example, the SMF can obtain the aforementioned eighth information from the NEF. For instance, the eighth information may be one or more FQDNs, or it may be EAS deployment information, or it may be included in the EAS deployment information.

[0553] In some possible implementations, the method 800 further includes: the SMF obtaining ninth information; the SMF determining the first DNS server based on the ninth information.

[0554] Optionally, in this implementation, since the DNS server corresponds to the service and / or network access point, it can be assumed that the DNS server can locally determine the servers that can be connected to within the range corresponding to the network access point (e.g., corresponding to one or more satellites). Therefore, S830 may not need to be executed.

[0555] The following are two examples of the ninth information, referred to as DNS server example 1 and DNS server example 2, which can be combined.

[0556] DNS server example 1: This ninth piece of information includes a mapping between at least one network access point and at least one DNS server.

[0557] In this context, UE#2 corresponds to the first network access point among the aforementioned at least one network access point (for example, the SMF determines the network access point corresponding to UE#2 based on the satellite accessed by UE#2 or the location of UE#2). This first network access point, in the aforementioned correspondence, corresponds to the first DNS server. Thus, the SMF can determine the aforementioned first DNS server.

[0558] DNS server example 2: This ninth piece of information includes a mapping between at least one service and at least one DNS server.

[0559] In this correspondence, the first DNS server corresponds to the second service. Thus, the SMF can determine the first DNS server based on the seventh piece of information (information indicating the second service) and the aforementioned correspondence.

[0560] In the combination of DNS server example 1 and DNS server example 2 described above, there can be a correspondence between at least one service, at least one network access point, and at least one DNS server. For example, if UE#2 corresponds to the first network access point, and the seventh information received by the SMF indicates the second service, the SMF can determine the first DNS server.

[0561] Based on the above scheme, the SMF can select a DNS server according to the mapping between services and DNS servers, and / or the mapping between network access points and DNS servers. The first DNS server can be a specific DNS server corresponding to the second service and / or the first network access point, thereby enabling better discovery of application servers for the first terminal. For example, compared to all services and / or network access points sharing a single DNS server, the above scheme can provide application server discovery services for the remaining services and / or network access points even if some DNS servers fail. Furthermore, the first DNS server can discover application servers connected to the satellite accessed by the first terminal without requiring address information (e.g., third address information).

[0562] In some possible implementations, method 800 also includes: S825.

[0563] S825, the SMF sends fourth address information to the EASDF. This fourth address information is used to identify the fourth application server deployed on the ground (e.g., AS, denoted as AS#4). Correspondingly, the EASDF receives the fourth address information from the SMF.

[0564] As an example, if the second terminal does not access the network via satellite, and / or if the second service is not deployed via satellite, the SMF can perform the above-mentioned S825.

[0565] The method for determining the above conditions can be found in the description of S820, and will not be repeated here.

[0566] The fourth application server (e.g., AS#4) can be used to provide the second service (i.e., the service corresponding to FQDN#2) for UE#2.

[0567] S840, the first DNS server receives a query message. This query message may include information about the second service.

[0568] The query message may also be called a DNS request message or other names, which are not limited in this application.

[0569] Optionally, the query message may also include third-party address information.

[0570] In some possible implementations, the query message mentioned above may originate from EASDF. For example, S840 can be described as: the first DNS server receives a query message from EASDF. Correspondingly, EASDF may send a query message to the first DNS server.

[0571] However, this application is not limiting; the query message in S840 described above can also come from other functions, such as UPF, DNS server, or other devices capable of cooperating or performing EAS discovery independently, and is not limited to EASDF. In other words, S840 described above can be replaced by the first DNS server receiving query messages from other functions.

[0572] S850, the first DNS server determines the third application server (e.g., EAS#3) based on the information from the second service.

[0573] In cases where the first DNS server is associated with the second service and / or the first network access point, the first DNS server may determine a third application server (e.g., EAS#3) that has a connection with the fourth satellite (e.g., RAN#3 satellite).

[0574] In some possible implementations, S850 includes: a first DNS server determining a third application server (e.g., EAS#3) based on third address information.

[0575] The third address information may be carried in the query message in S840. Other descriptions of the third address information are as described above, such as the relevant description in S830, and will not be repeated here.

[0576] The first DNS server can ensure that the resolved application server (e.g., EAS#3) can communicate with the third address information.

[0577] In some examples, the first DNS server may store ephemeris information. In some possible implementations, S850 includes: the first DNS server determining the third application server (e.g., EAS#3) based on the third address information and the ephemeris information.

[0578] For example, the first DNS server can also store IP ranges on each satellite, thereby enabling the determination of the third application server (e.g., EAS#3) based on the third address information, ephemeris information, and IP ranges on each satellite.

[0579] In some possible implementations, the method also includes S860 after S850.

[0580] S860, the first DNS server sends a response message to EASDF regarding the query message. This response message includes the address of the third application server. Correspondingly, EASDF receives the response message from the first DNS server regarding the query message.

[0581] The response message to this query message may also be called a DNS response message or other names, which are not limited in this application.

[0582] In some possible implementations, method 800 further includes: S870, EASDF sends a response message to the query message to UE#2. This response message may also be called an NDS response message or other names, which are not limited in this application.

[0583] Figure 9 is a schematic flowchart of another communication method 900 provided in an embodiment of this application. Method 900 can be used as a specific example of method 800. Method 900 can provide a dedicated first DNS server. This first DNS server can be used to resolve the application server (e.g., EAS#3) that has an inter-satellite link with the satellite (e.g., RAN#3 satellite) accessed by UE#2, thereby enabling UE#2 to access services normally. Optional operations in method 900 are shown in dashed lines in Figure 9. The various operations of method 900 are described below with reference to Figure 9.

[0584] S902, the AMF sends the identifier of the satellite (e.g., RAN#3 satellite) accessed by UE#2 to the SMF. Correspondingly, the SMF receives the identifier of the satellite accessed by UE#2 from the AMF.

[0585] The execution order of S902 described above can be after other operations in method 900, and this application does not impose any restrictions.

[0586] For example, S902 can be executed after the PDU session is established or during the PDU session establishment process.

[0587] Optionally, the identifier of the satellite accessed by UE#2 (e.g., RAN#3 satellite) is carried in the request message, for example, in the message Nsmf_PDUSession_CreateSMContext_Request(Nsmf_PDU session_createSM context_request). Here, Nsmf can be the service interface of the SMF.

[0588] For example, the identifier of the satellite accessed by the UE#2 (e.g., RAN#3 satellite) can be the value of the field "RAT type", that is, the identifier can be carried in the field "RAT type".

[0589] S904, SMF obtains information about the first DNS server. For example, the address information of the first DNS server.

[0590] Specifically, when resolving DNS request messages, the first DNS server can guarantee connectivity between the resolved EAS and the IP address in the ECS option. For example, the first DNS server can be configured with ephemeris information. Based on this ephemeris information, the first DNS server can ensure connectivity between the resolved EAS and the IP address in the ECS option.

[0591] The ephemeris information can be obtained through EAS deployment information (EDI) or other means, and this application does not impose any restrictions.

[0592] Optionally, the SMF also acquires service information deployed on satellites. S604 described above is an optional operation.

[0593] For example, the above business information can be in the form of an FQDN list.

[0594] Optionally, the aforementioned business information and / or the information of the first DNS server can be carried in a deployment notification message, for example, in the message Nnef_EASDeployment_Notify(Nnef_EAS deployment_notification). Here, Nnef can be a NEF service interface.

[0595] S910, UE#2 sends a DNS request message to EASDF. Correspondingly, EASDF receives the DNS request message from UE#2.

[0596] For details, please refer to the description in S320, which will not be repeated here.

[0597] S920, EASDF sends an indication of the FQDN to SMF. Correspondingly, SMF receives the indication of the FQDN from EASDF. This indication may specify the FQDN included in the DNS request message (e.g., FQDN#2).

[0598] Optionally, the aforementioned indication information is carried in a notification message, for example, in the message Neasdf_DNSContext_Notify(Neasdf_DNSContext_Notification). Here, Neasdf can be an EASDF service interface.

[0599] In some possible implementations prior to S920, EASDF could match DNS processing rules, as described in method 300, and will not be repeated here.

[0600] S930, the SMF sends the first DNS server information to the EASDF. Correspondingly, the EASDF receives the first DNS server information from the SMF.

[0601] Optionally, the information of the first DNS server can be carried in an update message, for example, in the Neasdf_DNSContext_Update message. Here, Neasdf can be an EASDF service interface.

[0602] For specific examples of S930 mentioned above, please refer to the previous text, such as the description of S820, which will not be repeated here.

[0603] Optionally, the update message may also include third address information. A description of the third address information is provided above, for example, in the relevant description of S830, and will not be repeated here.

[0604] In some examples, the first DNS server can be a specific DNS server corresponding to the DNAI (e.g., the first DNAI) to which UE#2 resides. In some exemplary scenarios, there are multiple specific DNS servers, each corresponding to a different DNAI. Thus, the SMF can select a specific DNS server based on the DNAI corresponding to the satellite accessed by UE#2.

[0605] In other examples, the primary DNS server can be a default, specific DNS server. That is, all DNAIs can share a single, specific DNS server.

[0606] The specific DNS servers mentioned above can be used to ensure connectivity between the resolved EAS and the IP address in the ECS option.

[0607] In some other possible implementations, if the SMF determines that the service corresponding to FQDN#2 is not deployed on the satellite, the SMF will not execute S930. In this case, the SMF can indicate fourth address information (e.g., address information of a UPF deployed on the ground) to the EASDF. The EASDF can then forward DNS request messages to a default DNS server (different from the aforementioned specific DNS server).

[0608] The following section continues to describe other operations of method 900 when executing S930.

[0609] S932, EASDF sends a DNS request message to the first DNS server. Correspondingly, the first DNS server receives the DNS request message from EASDF.

[0610] Optionally, the ECS option field in S932 may contain address information (e.g., third address information) provided by the SMF to the EASDF in S930.

[0611] Other descriptions of S932 above can be found in the example of S350, and will not be repeated here.

[0612] S934, the first DNS server sends a DNS response message to EASDF. Correspondingly, EASDF receives the DNS response message from the first DNS server.

[0613] The DNS response message may include FQDN#2 and address information for EAS (e.g., EAS#3).

[0614] In some examples, when resolving the DNS request message, the first DNS server can ensure that the resolved EAS (e.g., EAS#3) is connected to the address information (e.g., third address information) in the ECS option.

[0615] In other examples, the first DNS server is the specific DNS server corresponding to the DNAI (e.g., the first DNAI) where UE#2 resides. Even without third address information, the first DNS server can resolve to the EAS (e.g., EAS#3) that has a connection with the satellite accessed by UE#2.

[0616] Other descriptions of S934 above can be found in the example of S355, and will not be repeated here.

[0617] Method 900 may also include operations similar to S370, S374, S376 and S380, which will not be described in detail here.

[0618] The communication device provided in the embodiments of this application will be described in detail below with reference to Figures 10 to 13. The description of the device embodiments corresponds to the description of the method embodiments. Therefore, for content not described in detail, please refer to the method embodiments above. For the sake of brevity, some content will not be repeated.

[0619] This application embodiment can divide the communication device into functional modules according to the above method example. For example, each function can be divided into its own functional modules, or two or more functions can be integrated into one processing module. The integrated modules can be implemented in hardware, software, or a combination of both. The module division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in actual implementation. The following description uses the division of functional modules according to each function as an example.

[0620] Figure 10 is an exemplary block diagram of a communication device 1000 provided in an embodiment of this application.

[0621] As shown in Figure 10, for example, the communication device 1000 may include a chip system 1010, a memory 1020, a bus 1030, a power management module 1040, or a transceiver 1050, etc.

[0622] The chip system 1010 can be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed through integrated logic circuits in the hardware of the chip system 1010 or through software instructions.

[0623] As an example and not a limitation, the chip system 1010 may include circuitry or chips responsible for signal processing (such as a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip or system-in-package (SIP) chip containing a modem core).

[0624] Optionally, the chip system 1010 may also include a memory (such as a cache) for storing instructions and data. In some embodiments, the memory in the chip system 1010 is a cache memory. This memory can store instructions or data that the chip system 1010 has just used or that are used repeatedly. If the chip system 1010 needs to use the instruction or data again, it can directly retrieve it from the memory. This avoids repeated accesses, reduces the waiting time of the chip system 1010, and thus improves the efficiency of the system.

[0625] In some embodiments, the chip system 1010 may include one or more interfaces. Interfaces may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc.

[0626] The memory 1020 may include random access memory (RAM) and read-only memory (ROM). The memory 1020 may store computer-readable, computer-executable code, including instructions that, when executed, cause the processor to perform the various functions described in this application.

[0627] Optionally, the code may include instructions for implementing various aspects of the embodiments of this application, such as instructions for receiving first information. The code may be stored in a non-transitory computer-readable medium such as system memory or other types of memory. In some cases, the code may not be directly executable by the chip system 1010, but may enable a computer (e.g., at compile and execution time) to perform the functions described in this application. In some cases, memory 1020 may contain a basic I / O system that can control basic hardware or software operations, such as interaction with peripheral components or devices.

[0628] For example, the chip system 1010 executes various functional applications and data processing of the communication device 1000 by running instructions stored in the memory 1020. For instance, when the communication device 1000 transfers files with other devices (which may also be terminals or access network devices), the chip system 1010 of the communication device 1000 can call the computer-executable program code stored in the memory 1020 to implement the communication method provided in the embodiments of this application.

[0629] In addition, the memory 1020 can be integrated into the chip system 1010 or independent of the chip system 1010.

[0630] For example, bus 1030 may be USB for supporting communication between various parts of communication device 1000.

[0631] The power management module 1040 is used to receive charging input from the charger. Optionally, the power management module 1040 can also supply power to the communication device 1000 while charging it (e.g., the battery module of the communication device 1000). By way of example and not limitation, the power management module 1040 can also supply power to other devices besides the communication device 1000.

[0632] Transceiver 1050 can communicate bidirectionally via one or more antennas, a wired link, or a wireless link. For example, transceiver 1050 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. Transceiver 1050 may also include a modem for modulating packets and providing the modulated packets to the antenna for transmission, and for demodulating packets received from the antenna. Transceiver 1050 may include a receiver and a transmitter, the receiver performing the function of receiving information and the transmitter performing the function of transmitting information.

[0633] In some cases, a wireless device may include a single antenna. However, in other cases, the device may have more than one antenna, such as antenna 1 and antenna 2 shown in FIG. 10, which may be capable of simultaneously transmitting or receiving multiple wireless transmissions. Exemplarily, antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in the communication device 1000 can be used to cover one or more communication frequency bands. Different antennas can also be multiplexed to improve antenna utilization. For example, antenna 1 can be multiplexed as a diversity antenna for a wireless local area network. In other embodiments, the antennas can be used in conjunction with a tuning switch. The communication device 1000 can transfer files to other devices via wireless communication functions.

[0634] In one design, the communication device 1000 may correspond to the first network element in the above method embodiment.

[0635] The device 1000 can implement the steps or processes corresponding to the first network element in the above method embodiment. The transceiver 1050 can be used to perform the transmission and reception related operations of the first network element in the above method embodiment, such as performing step S530 or S810 in the above method embodiment. The chip system 1010 can be used to perform the processing related operations of the first network element in the above method embodiment.

[0636] In another design, the communication device 1000 may correspond to the third network element in the above method embodiment.

[0637] The device 1000 can implement the steps or processes corresponding to the third network element in the above method embodiment. The transceiver 1050 can be used to perform the transmission and reception related operations of the third network element in the above method embodiment, such as executing step S564 in the above method embodiment. The chip system 1010 can be used to perform the processing related operations of the third network element in the above method embodiment.

[0638] In another design, the communication device 1000 may correspond to the first DNS server in the above method embodiment.

[0639] The device 1000 can implement the steps or processes corresponding to those performed by the first DNS server in the above method embodiments. The transceiver 1050 can be used to perform operations related to the transmission and reception of the first DNS server in the above method embodiments, such as executing step S840. The chip system 1010 can be used to perform processing-related operations of the first DNS server in the above method embodiments, such as S850.

[0640] In the design of the communication device 1000 corresponding to the terminal device, the communication device 1000 may include modules such as the short-range communication module 1064, sensor 1061, display 1062, or camera 1063 as shown in FIG10.

[0641] The short-range communication module 1064 may include modules that support short-range communication, such as Wi-Fi and Bluetooth.

[0642] For example, sensor 1061 may include pressure sensor, gyroscope sensor, barometric pressure sensor, magnetic sensor, accelerometer, distance sensor, proximity sensor, fingerprint sensor, temperature sensor, touch sensor, ambient light sensor, bone conduction sensor, etc.

[0643] For example, the display 1062 is used to display images, videos, etc. The display includes a display panel. The display panel can be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode (AMOLED), a flexible light-emitting diode (FLED), a mini light-emitting diode (LED), a micro LED, a micro OLED, a quantum dot light-emitting diode (QLED), etc. For example, in this embodiment, the display can be used to display the interface required by the communication device 1000. For example, the communication device 1000 implements the display function through a graphics processing unit (GPU), a display, and an application processor. The GPU is a microprocessor for image processing, connected to the display and the application processor. The GPU is used to perform mathematical and geometric calculations and for graphics rendering. The chip system 1010 may include one or more GPUs that execute program instructions to generate or change display information.

[0644] For example, camera 1063 is used to acquire images, videos, etc.

[0645] It is understood that the structure shown in Figure 10 does not constitute a specific limitation on the communication device 1000, and the specific structure of the terminal device and / or access network device can be referred to Figure 10. In some embodiments, the communication device 1000 may also include more or fewer components than shown in Figure 10, or combine some components, or split some components, or have different component arrangements, etc. Alternatively, some components shown in Figure 10 may be implemented in hardware, software, or a combination of software and hardware, and the terminal device and / or access network device may add or reduce components based on the structure given in Figure 10.

[0646] Figure 11 is a schematic block diagram of a communication device 2000 provided in an embodiment of this application.

[0647] As shown in Figure 11, the communication device 2000 may include a baseband unit 2010, which can communicate with external devices via a cellular radio frequency (RF) transceiver 2020 (e.g., if the communication device 2000 is a terminal device, the baseband unit 2010 can communicate with access network devices via the cellular RF transceiver 2020; or, if the communication device 2000 is an access network device, the baseband unit 2010 can communicate with terminal devices and / or core network devices via the cellular RF transceiver 2020).

[0648] By way of example, baseband unit 2010 may include computer-readable medium / memory. Baseband unit 2010 may be responsible for general processing, including the execution of software stored on computer-readable medium / memory. When executed by baseband unit 2010, the software causes baseband unit 2010 to perform the various functions described above. Computer-readable medium / memory may also be used to store data manipulated by baseband unit 2010 when executing the software.

[0649] Optionally, the baseband unit 2010 further includes a receiving unit 2011, a management unit 2012, and a transmitting unit 2013. When the communication device 2000 is applied to the first network element, the management unit 2012 may include one or more sub-units shown in FIG. 11. For example, an address information generation sub-unit, wherein the address information generation sub-unit can be used to perform the operation of generating first address information, second address information, third address information, or fourth address information in the above method embodiments. The units within the management unit 2011 may be stored in a computer-readable medium / memory and / or configured as hardware within the baseband unit 2010. The receiving unit 2011 and the transmitting unit 2013 may be referred to as transceiver units.

[0650] When the communication device 2000 is used to implement the function of the first network element in the above method embodiments, the receiving unit 2011 is used to perform the receiving step of the first network element, the sending unit 2013 is used to perform the sending step of the first network element, and the management unit 2012 is used to perform the processing step of the first network element.

[0651] For example, when the communication device 2000 is used to implement the function of the first network element in the above method embodiments, the receiving unit 2011 is used to receive first information from the second network element, wherein the first information is used to indicate a first application server, the first application server is deployed on a first satellite, the first application server is used to provide a first service to a first terminal, the second satellite is used to provide access service to the first terminal, and there is no connection between the first satellite and the second satellite; the sending unit 2013 is used to send second information, wherein the second information is used to determine a second application server, the second application server is deployed on the ground, the second application server is used to provide the first service to the first terminal; or, the second information is used to determine a third satellite, the third satellite is used to replace the second satellite to provide access service to the first terminal, and there is a connection between the third satellite and the first satellite.

[0652] For example, when the device 2000 is used to perform the methods in Figures 5 to 9, the receiving unit 2011 can be used to perform the step of receiving information in the method; the management unit 2012 can be used to perform the processing step in the method; and the sending unit 2013 can be used to perform the step of sending information in the method.

[0653] When the communication device 2000 is used to implement the function of the third network element in the above method embodiments, the receiving unit 2011 is used to perform the receiving step of the third network element, the sending unit 2013 is used to perform the sending step of the third network element, and the management unit 2012 is used to perform the processing step of the third network element.

[0654] For example, when the communication device 2000 is used to implement the function of the third network element in the above method embodiments, the receiving unit 2011 is used to receive second information from the first network element, the second information being used to determine the third satellite; the sending unit 2013 is used to send sixth information to the second satellite, the second satellite being used to access the first terminal, the sixth information being used to instruct the first terminal to be redirected to the third satellite, the third satellite being connected to the first satellite, the first satellite being deployed with a first application server, the first application server being used to provide a first service to the first terminal.

[0655] For example, when the device 2000 is used to perform the methods in Figures 5 to 9, the receiving unit 2011 can be used to perform the step of receiving information in the method; the management unit 2012 can be used to perform the processing step in the method; and the sending unit 2013 can be used to perform the step of sending information in the method.

[0656] When the communication device 2000 is used to implement the function of the first network element in the above method embodiments, the receiving unit 2011 is used to perform the receiving step of the first network element, the sending unit 2013 is used to perform the sending step of the first network element, and the management unit 2012 is used to perform the processing step of the first network element.

[0657] For example, when the communication device 2000 is used to implement the function of the first network element in the above method embodiments, the receiving unit 2011 is used to receive seventh information, wherein the seventh information is used to indicate information of the second service; when the second terminal accesses the network via satellite, and / or, when the second service is deployed on a satellite, the sending unit 2013 is used to send information of the first DNS server to the second network element, wherein the first DNS server is used to determine a third application server that has a connection with the fourth satellite, wherein the third application server is used to provide the second service to the second terminal, and the fourth satellite is used to provide access service to the second terminal.

[0658] For example, when the device 2000 is used to perform the methods in Figures 5 to 9, the receiving unit 2011 can be used to perform the step of receiving information in the method; the management unit 2012 can be used to perform the processing step in the method; and the sending unit 2013 can be used to perform the step of sending information in the method.

[0659] When the communication device 2000 is used to implement the function of the first DNS server in the above method embodiments, the receiving unit 2011 is used to perform the receiving step of the first DNS server, the sending unit 2013 is used to perform the sending step of the first DNS server, and the management unit 2012 is used to perform the processing step of the first DNS server.

[0660] For example, when the communication device 2000 is used to implement the function of the first DNS server in the above method embodiments, the receiving unit 2011 is used to receive a query message, which includes third address information and second service information; the management unit 2012 is used to determine a third application server based on the third address information and the second service information, the third application server is connected to a fourth satellite, the third application server is used to provide the second service to the second terminal, the fourth satellite is used to provide access service to the second terminal, and the third address information is used to indicate the fourth satellite, or the third address information is used to indicate a satellite connected to the fourth satellite.

[0661] For example, when the device 2000 is used to perform the methods in Figures 5 to 9, the receiving unit 2011 can be used to perform the step of receiving information in the method; the management unit 2012 can be used to perform the processing step in the method; and the sending unit 2013 can be used to perform the step of sending information in the method.

[0662] For a more detailed description of the receiving unit 2011, the management unit 2012, and the sending unit 2013, please refer to the relevant descriptions in the above method embodiments, which will not be repeated here.

[0663] By way of example and not limitation, the chip system in this application is shown in Figure 12, which is a schematic block diagram of the chip system 3000 provided in an embodiment of this application. The chip system includes, but is not limited to, a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip or a system-in-package (SIP) chip containing a modem core.

[0664] As can be seen from Figure 12, the chip system (or processing system) includes a processor 3010, a memory 3020, and an input / output interface 3030.

[0665] The processor 3010 can be a processing circuit in the chip system (including at least one processor, such as processor 1 and processor 2 as shown in FIG. 12). The processor 3010 can be coupled to the memory 3020, and call the instructions in the memory 3020, so that the chip system can implement the methods and functions of the various embodiments of this application. The input / output interface 3030 can be an input / output circuit in the chip system, which outputs the information processed by the chip system, or inputs the data or signaling information to be processed into the chip system for processing.

[0666] As one approach, the chip system is used to implement the operations performed by the first network element, the third network element, or the first DNS server in the various method embodiments described above.

[0667] For example, the processor 3010 is used to implement the processing-related operations performed by the first network element, the third network element, or the first DNS server in the above method embodiments, as described in the foregoing embodiments; the input / output interface 3030 is used to implement the sending and / or receiving-related operations performed by the first network element, the third network element, or the first DNS server in the above method embodiments, as described in the foregoing embodiments.

[0668] As an example and not a limitation, the chip system in this application is shown in Figure 13, which is a schematic block diagram of the chip system 4000 provided in an embodiment of this application.

[0669] As shown in Figure 13, the chip system (or processing system) includes an input / output interface 4010 and logic circuitry 4020. The input / output interface 4010 can be an input / output circuit within the chip system, outputting processed information or inputting data or signaling information to be processed into the chip system for processing. For details, please refer to the descriptions in the preceding embodiments, executing, for example, the embodiments shown in Figures 5 to 9. The logic circuitry 4020 is used to execute the aforementioned communication method, and for details, please refer to the descriptions in the preceding embodiments.

[0670] As one approach, the chip system is used to implement the operations performed by the first network element, the third network element, or the first DNS server in the various method embodiments described above.

[0671] For example, logic circuit 4020 is used to implement processing-related operations performed by the first network element, the third network element, or the first DNS server in the above method embodiments; input / output interface 4010 is used to implement sending and / or receiving-related operations performed by the first network element, the third network element, or the first DNS server in the above method embodiments.

[0672] This application also provides a computer-readable storage medium storing computer instructions for implementing the methods executed by the device in the above-described method embodiments.

[0673] For example, when the computer program is executed by a computer, it enables the computer to implement the methods executed by the first network element, the third network element, or the first DNS server in the various embodiments of the above methods.

[0674] This application also provides a computer program product comprising instructions that, when executed by a computer, implement the methods performed by the first network element, the third network element, or the first DNS server in the above-described method embodiments.

[0675] This application also provides a communication system, including the aforementioned third network element and first network element. Alternatively, the communication system includes the first network element and a first DNS server.

[0676] The explanations and beneficial effects of the relevant contents in any of the devices provided above can be referred to the corresponding method embodiments provided above, and will not be repeated here.

[0677] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0678] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0679] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0680] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0681] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0682] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

A communication method, characterized in that, The method is applied to a first network element, and the method includes: Receive first information from a second network element, wherein the first information is used to instruct a first application server, the first application server is deployed on a first satellite, the first application server is used to provide a first service to a first terminal, the second satellite is used to provide access service to the first terminal, and there is no connection between the first satellite and the second satellite; Send a second message, wherein the second message is used to identify a second application server, the second application server is deployed on the ground, and the second application server is used to provide the first service to the first terminal; Alternatively, the second information may be used to identify a third satellite, which may replace the second satellite in providing access services to the first terminal, and the third satellite may be connected to the first satellite. The method according to claim 1, characterized in that, The sending of the second information includes: The second information is sent to the second network element. The second information includes first address information, which is used to determine the second application server deployed on the ground. The method according to claim 1 or 2, characterized in that, The method further includes: Send a third message to the second network element, the third message being used to instruct the second network element not to send information about the server deployed on the ground to the first network element, and / or, the third message being used to instruct the second network element not to send information about the first service to the first network element. The method according to any one of claims 1 to 3 is characterized in that, The method further includes: Configure the first terminal to access the second application server through the anchor user plane network element. The method according to claim 1, characterized in that, The sending of the second information includes: The second information is sent to a third network element. The second information includes information about the first satellite, which is used to determine the third satellite with which there is a connection. The method according to any one of claims 1 to 5, characterized in that, The method further includes: The system receives fourth information from a fourth network element, which indicates that there is no connection between the first satellite and the second satellite. The method according to any one of claims 1 to 6, characterized in that, The method further includes: The fifth information is sent to the fourth network element, and the fifth information is used to query whether there is a connection between the first satellite and the second satellite. The method according to claim 7, characterized in that, The fifth piece of information includes at least one of the information of the first application server, the information of the first satellite, or the information of the second satellite. The method according to any one of claims 1 to 8, characterized in that, Before receiving the first information from the second network element, the method further includes: Send the second address information to the second network element. The second address information is used to determine the first application server deployed on the satellite. The method according to claim 9, characterized in that, The method further includes: Obtain information about the first service; The step of sending the second address information to the second network element includes: If the server corresponding to the first service is deployed on a satellite, the second address information is sent to the second network element. A communication method, characterized in that, The method is applied to a third network element, and the method includes: Receive second information from the first network element, the second information being used to determine the third satellite; A sixth message is sent to a second satellite, which is used to access the first terminal. The sixth message is used to instruct the first terminal to be redirected to the third satellite. There is a connection between the third satellite and the first satellite. The first satellite is equipped with a first application server, which is used to provide a first service to the first terminal. The method according to claim 11, characterized in that, The method further includes: The third satellite is determined based on the second information. The third satellite is connected to the first satellite and is equipped with access network equipment. The method according to claim 12, characterized in that, The method further includes: Obtain ephemeris information; Determining the third satellite based on the second information includes: The third satellite is determined based on the second information and the ephemeris information. A communication method, characterized in that, The method is applied to a first network element, and the method includes: Receive seventh information, wherein the seventh information is used to indicate information of the second service; When the second terminal accesses the network via satellite, and / or, if the second service is deployed on a satellite, it sends information about a first Domain Name System (DNS) server to the second network element. The first DNS server is used to determine a third application server that has a connection with a fourth satellite. The third application server is used to provide the second service to the second terminal, and the fourth satellite is used to provide access services to the second terminal. The method according to claim 14, characterized in that, The method further includes: Send a third address information to the second network element. The third address information is used to indicate the fourth satellite, or the third address information is used to indicate a satellite connected to the fourth satellite. The method according to claim 15, characterized in that, The first DNS server is used to determine, based on the third address information, the third application server that has a connection with the fourth satellite. The method according to claim 15 or 16 is characterized in that, The third address information is the address information of the fourth network element, which is deployed on the fourth satellite, or there is a connection between the satellite on which the fourth network element is deployed and the fourth satellite. The method according to any one of claims 14 to 17, characterized in that, The method further includes: Obtain eighth information, which is used to indicate at least one service deployed on the satellite; Based on the eighth piece of information, it is determined that the second service is deployed on the satellite, and the second service belongs to the at least one service. The method according to any one of claims 14 to 18, characterized in that, The method further includes: Obtain the ninth information, which includes the correspondence between at least one network access point and at least one DNS server, and / or the correspondence between at least one service and at least one DNS server, wherein the second terminal corresponds to the first network access point among the at least one network access point; Based on the ninth information, the first DNS server is determined, wherein the first DNS server corresponds to the first network access point, and / or the first DNS server corresponds to the second service. The method according to any one of claims 14 to 19, characterized in that, The method further includes: If the second terminal does not access the network via satellite, and / or if the second service is not deployed on satellite, the second terminal sends fourth address information to the second network element. The fourth address information is used to determine a fourth application server deployed on the ground. The fourth application server is used to provide the second service to the second terminal. A communication method, characterized in that, The method is applied to a first domain name system (DNS) server, and the method includes: Receive a query message, the query message including third address information and second service information; Based on the third address information and the information of the second service, a third application server is determined. The third application server is connected to the fourth satellite. The third application server is used to provide the second service to the second terminal. The fourth satellite is used to provide access service to the second terminal. The third address information is used to indicate the fourth satellite, or the third address information is used to indicate a satellite connected to the fourth satellite. The method according to claim 21, characterized in that, The step of determining the third application server based on the third address information and the second service information includes: The third application server is determined based on the third address information, the second service information, and the ephemeris information. The method according to claim 21 or 22 is characterized in that, The third address information is the address information of the fourth network element, which is deployed on the fourth satellite, or the satellite on which the fourth network element is deployed is connected to the fourth satellite. A communication device, characterized in that, include: At least one processor, the at least one processor being configured to execute a computer program or instructions to cause the method of any one of claims 1 to 23 to be performed. The communication device according to claim 24 is characterized in that, The communication device further includes a memory for storing the computer program or the instructions. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instructions that, when executed, cause the method of any one of claims 1 to 23 to be performed. A computer program product, characterized in that, Includes a computer program or instructions, which, when executed, implement the method as described in any one of claims 1 to 23. A chip or chip system, characterized in that, include: At least one processor, the at least one processor being configured to execute a computer program or instructions to cause the method of any one of claims 1 to 23 to be performed.

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