Communication method and communication apparatus

Abstract

Provided in the present application are a communication method and a communication apparatus. In the method, a first network element may determine a first server (e.g., a local DNS server or an EAS) providing a corresponding service for a terminal; in addition, it is not necessary for a UE to re-initiate a DNS process, and the first server can be determined directly on the basis of ephemeris information and first position information of the terminal, thereby optimizing an EAS reselection process for UEs, and thus reducing satellite-terrestrial interactions and lowering communication overheads.

Description

A communication method and communication device

[0001] This application claims priority to Chinese Patent Application No. 202410918233.3, filed on July 9, 2024, entitled "A Communication Method and Communication Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a communication method and communication device. Background Technology

[0003] In future network deployments, edge application servers (EAS) may be deployed on low-Earth orbit (LEO) satellites to provide services to ground-based user equipment (UEs). However, LEO satellites move at high speeds relative to the ground, providing limited coverage time for a stationary UE, necessitating frequent EAS replacements. One possible implementation requires the UE to re-initiate the Domain Name System (DNS) process; if the DNS server is deployed on the ground, frequent satellite-to-ground interactions are required, increasing communication overhead. Another possible implementation allows the UE to connect to its previous EAS via inter-satellite links without replacement, but this approach may increase latency and compromise service quality. Summary of the Invention

[0004] This application provides a communication method and a communication device, which reduces satellite-to-ground interaction and helps to reduce communication overhead.

[0005] Firstly, this application provides a communication method, which can be implemented by a first network element. For example, the first network element can be a functional network element such as a session management function (SMF), access and mobility management function (AMF), or policy control function (PCF), or a functional entity capable of implementing these functions. Specifically, the first network element determines information about a first server based on ephemeris information and the terminal's first location information. The information about the first server includes a local domain name system server or one or more application servers corresponding to various services. The first network element sends the information about the first server to the terminal; the information about the first server is related to a first satellite accessed by the terminal.

[0006] In this method, the first network element can be determined as the first server that provides the corresponding service to the terminal. The UE does not need to re-initiate the DNS process. Instead, the first server can be determined based on the ephemeris information and the terminal's first location information. This optimizes the process of the UE reselecting the EAS, thereby reducing satellite-to-ground interaction and lowering communication overhead.

[0007] In one possible implementation, the ephemeris information includes at least the ephemeris information of the first satellite, or the ephemeris information of more satellites, such as the ephemeris information of all satellites in the constellation / orbit to which the first satellite is located, etc., which is not limited in this application.

[0008] In one possible implementation, before the first network element determines the first server based on ephemeris information and the terminal's first location information, the first network element determines that the terminal accesses the network via a non-terrestrial network.

[0009] In one possible implementation, the first network element receives first indication information, which is used to instruct the terminal to access the first satellite.

[0010] In the above embodiments, the first network element can determine that the terminal accesses through a non-terrestrial network. For example, the terminal accessing through a non-terrestrial network can be at least one of the following: the terminal accesses through a satellite, the terminal accesses through a non-geostationary satellite orbit (NGSO) satellite, the terminal accesses through a LEO satellite, the terminal accesses through a drone, etc.

[0011] In one possible implementation, the information of the first server is a first correspondence relationship, which includes one or more of the following:

[0012] The mapping relationship between one or more satellites and local domain name system servers;

[0013] The correspondence between one or more satellites, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0014] The correspondence between time and the local domain name system server;

[0015] The correspondence between time, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0016] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0017] In one possible implementation, the application server corresponding to one or more services may be the application server corresponding to one or more service domain names, or the application server corresponding to one or more service identifiers.

[0018] In the above embodiments, the first correspondence is defined as the correspondence between satellites (such as the first satellite and other satellites) and the local domain name system server / application server corresponding to one or more services, or the correspondence between time (such as the current time and other times) and the local domain name system server / application server corresponding to one or more services.

[0019] In one possible implementation, the information of the first server is a first correspondence relationship, which includes one or more of the following:

[0020] The mapping between one or more satellites, one or more data network names, and local domain name system servers;

[0021] The correspondence between one or more satellites, one or more data network names, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0022] The mapping between time, one or more data network names, and the local domain name system server;

[0023] The correspondence between time, one or more data network names, one or more business domain names and the application servers corresponding to the one or more business domain names;

[0024] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0025] In the above embodiments, when the terminal has not yet established a session, the first correspondence is further defined as the correspondence between satellites (such as the first satellite and other satellites) and one or more data network names and local domain name system servers / application servers corresponding to one or more services, or the correspondence between time (such as the current time and other times) and one or more data network names and local domain name system servers / application servers corresponding to one or more services.

[0026] In one possible implementation, the information of the first server is a first correspondence relationship, which includes one or more of the following:

[0027] The mapping relationship between one or more satellites and local domain name system servers;

[0028] The mapping relationship between one or more satellites, one or more business domain names, and the application servers corresponding to one or more business domain names;

[0029] The correspondence between time and the local domain name system server;

[0030] The mapping relationship between time and application servers corresponding to one or more business domain names;

[0031] In one possible implementation, one or more satellites include a first satellite; time includes the current time; one or more service domains include a first service domain, which is the service domain corresponding to the service requested by the terminal.

[0032] In the above embodiments, when the terminal's service has been determined (such as the first service domain name), the first correspondence is further defined as the correspondence between satellites (such as the first satellite and other satellites) and the application servers corresponding to the local domain name system server / one or more service domain names (including the first service domain name), or the correspondence between time (such as the current time and other times) and the application servers corresponding to the local domain name system server / one or more service domain names (including the first service domain name).

[0033] In one possible implementation, one or more times include a first time, which is the time when the first satellite provides services to the terminal.

[0034] In one possible implementation, the first network element determines the first correspondence based on one or more of the following: first location information, first service information of the terminal, first satellite, and ephemeris information; the first service information includes at least one of the following: data network name, network slice selection auxiliary information, and service domain name.

[0035] In one possible implementation, the information of the first server or the first correspondence is carried in the first message, which is any one of the following: session establishment acceptance message, session modification instruction, registration acceptance message, or UE configuration update instruction.

[0036] In one possible implementation, when the location of the terminal changes, the first network element sends a second correspondence; the location information of the terminal after the change is different from the first location information.

[0037] In one possible implementation, when the location of the terminal changes, the first network element may determine that the terminal's location has changed.

[0038] In this implementation, when the location of the terminal changes, the first network element needs to update the correspondence (from the first correspondence to the second correspondence) and send the updated correspondence to the terminal (e.g., send the second correspondence).

[0039] Secondly, this application provides a communication method, which can be implemented by a terminal, such as a terminal device or chip, or a device capable of implementing the functions of a terminal device. When the terminal initiates a first service, it determines a second server based on a first correspondence. The second server includes an application server to be accessed or a local domain name system server; the application server to be accessed or the local domain name system server is deployed on a satellite. The terminal then accesses the second server.

[0040] In this method, when the terminal initiates the first service, it can determine the second server that provides the corresponding service to the terminal based on the first correspondence. The UE does not need to re-initiate the DNS process. Instead, the second server can be determined based on the first correspondence, which optimizes the process of the UE reselecting the EAS, thereby reducing satellite-to-ground interaction and reducing communication overhead.

[0041] In one possible implementation, when the terminal initiates the first service, it can be replaced by when the application / first service is detected; or when the terminal initiates the first service, it can be replaced by when the traffic / packet / data corresponding to the first service is routed; or when the terminal initiates the first service, it can be replaced by when accessing / is about to access the first service (such as a fully qualified domain name (FQDN)) (try to access to an FQDN / service or try to access EAS corresponding to an FQDN / service).

[0042] In one possible implementation, the application server or local domain name system server to be accessed can be replaced with the target application server or local domain name system server (target EAS / DNS server); or, the application server or local domain name system server to be accessed can be replaced with the application server or local domain name system server to be accessed (trys to access EAS / DNS server).

[0043] In one possible implementation, the terminal accesses a first satellite. The first correspondence includes one or more of the following: a correspondence between the first satellite and a local domain name system server, a correspondence between the first satellite and an application server corresponding to the first service, a correspondence between a first time and the local domain name system server, and a correspondence between a first time and an application server corresponding to the first service. Here, the first time refers to the time during which the first satellite provides services to the terminal.

[0044] In one possible implementation, the first correspondence includes one or more of the following:

[0045] The mapping relationship between one or more satellites and local domain name system servers;

[0046] The correspondence between one or more satellites, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0047] The correspondence between time and the local domain name system server;

[0048] The correspondence between time, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0049] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0050] In the above embodiments, the first correspondence is defined as the correspondence between satellites (such as the first satellite and other satellites) and the local domain name system server / application server corresponding to one or more services, or the correspondence between time (such as the current time and other times) and the local domain name system server / application server corresponding to one or more services.

[0051] In one possible implementation, the first correspondence includes one or more of the following:

[0052] The mapping between one or more satellites, one or more data network names, and local domain name system servers;

[0053] The correspondence between one or more satellites, one or more data network names, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0054] The mapping between time, one or more data network names, and the local domain name system server;

[0055] The correspondence between time, one or more data network names, one or more business domain names and the application servers corresponding to the one or more business domain names;

[0056] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0057] In the above embodiments, when the terminal has not yet established a session, the first correspondence is further defined as the correspondence between satellites (such as the first satellite and other satellites) and one or more data network names and local domain name system servers / application servers corresponding to one or more services, or the correspondence between time (such as the current time and other times) and one or more data network names and local domain name system servers / application servers corresponding to one or more services.

[0058] In one possible implementation, the first correspondence includes one or more of the following:

[0059] The mapping relationship between one or more satellites and local domain name system servers;

[0060] The mapping relationship between one or more satellites, one or more business domain names, and the application servers corresponding to one or more business domain names;

[0061] The correspondence between time and the local domain name system server;

[0062] The mapping relationship between time, one or more business domain names, and the application servers corresponding to one or more business domain names;

[0063] In one possible implementation, one or more satellites include a first satellite; time includes the current time; one or more service domains include a first service domain, which is the service domain corresponding to the service requested by the terminal.

[0064] In the above embodiments, when the terminal's service has been determined (such as the first service domain name), the first correspondence is further defined as the correspondence between satellites (such as the first satellite and other satellites) and the application servers corresponding to the local domain name system server / one or more service domain names (including the first service domain name), or the correspondence between time (such as the current time and other times) and the application servers corresponding to the local domain name system server / one or more service domain names (including the first service domain name).

[0065] In one possible implementation, one or more times include a first time, which is the time when the first satellite provides services to the terminal.

[0066] In one possible implementation, the terminal determines the second server based on a first correspondence and at least one of the following: the first service, service information corresponding to the first service, the first satellite accessed by the terminal, and the current time; the second server is a server deployed on the first satellite or the second satellite. The second satellite is either a satellite with an application server or a local domain name system server deployed thereon and connected to the first satellite; or the second satellite is the satellite with an application server or a local domain name system server deployed thereon and is the closest to the first satellite.

[0067] In one possible implementation, the connection between the second satellite and the first satellite could mean that there is an inter-satellite link between them; or, the second satellite and the first satellite could communicate via one-hop or multi-hop inter-satellite links. For example, assuming that both the second satellite and the first satellite are connected to a certain satellite via an inter-satellite link, then the second satellite and the first satellite can communicate through that satellite.

[0068] In one possible implementation, the second satellite being closest to the first satellite can be defined as having the shortest straight-line distance between the second and first satellites (e.g., shorter than the distance between the second and first satellites in the same constellation); or having the fewest inter-satellite link hops between the second and first satellites (e.g., fewer than the number of inter-satellite link hops between the second and first satellites in the same constellation).

[0069] In one possible implementation, the terminal receives a first message, which includes a first correspondence. The first message can be any of the following: a session establishment acceptance message, a session modification instruction, a registration acceptance message, or a UE configuration update instruction.

[0070] In one possible implementation, when the terminal's location changes, the terminal receives a second correspondence; the changed location information of the terminal is different from the first location information.

[0071] In one possible implementation, when the location of the terminal changes, the first network element may determine that the terminal's location has changed.

[0072] In this embodiment, when the location of the terminal changes, the correspondence will be updated, and the terminal can receive the updated correspondence (such as the second correspondence).

[0073] Thirdly, this application provides a communication method, which can be implemented by a first satellite. For example, the first satellite can be a satellite, a functional entity performing related functions on a satellite, or an access network device deployed on a satellite. Specifically, the first satellite acquires a third correspondence; the third correspondence is the address of a local domain name system server, or the third correspondence includes a correspondence between the local domain name system server and a data network name; the local domain name system server is associated with the first satellite. The first satellite then transmits the third correspondence.

[0074] In this method, the first satellite can determine the third correspondence and send the third correspondence to the terminal, which optimizes the UE reselection of EAS process, thereby reducing satellite-to-ground interaction and reducing communication overhead.

[0075] In one possible implementation, when the third correspondence is the address of the local domain name system server, the first satellite obtains the address of the local domain name system server and sends the address of the local domain name system server.

[0076] In one possible implementation, the local domain name system server is deployed on the first satellite; or, the local domain name system server is deployed on the second satellite, which is a satellite with the local domain name system server deployed and connected to the first satellite; or, the local domain name system server is deployed on the second satellite, which is a satellite with the local domain name system server deployed and is the closest to the first satellite.

[0077] In one possible implementation, the first satellite broadcasts the third correspondence, or the first satellite sends the third correspondence to the terminal via a radio resource control (RRC) message, and the terminal accesses the first satellite.

[0078] In one possible implementation, the first satellite broadcasting the third correspondence may be a master information block (MIB) or system information block (SIB) message sent by the first satellite, which includes the third correspondence.

[0079] In one possible implementation, the first satellite receives a second message requesting the address of a local Domain Name System (DNS) server deployed on the first satellite. The first satellite then sends a third mapping relationship to the terminal via an RRC message.

[0080] In one possible implementation, the third correspondence includes at least one of the following:

[0081] The mapping between one or more satellites, one or more data network names, and local domain name system servers;

[0082] The mapping between time, one or more data network names, and the local domain name system server;

[0083] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0084] In the above embodiments, the first correspondence is defined as the correspondence between satellites (such as the first satellite and other satellites), one or more data network names and the local domain name system server, or the correspondence between time (such as the current time and other times) and one or more data network names and the local domain name system server.

[0085] Fourthly, this application provides a communication method, which can be implemented by a terminal, such as a terminal device or chip, or a device capable of implementing the functions of a terminal device. The terminal receives a third correspondence, which is the address of a local domain name system server, or the third correspondence includes a correspondence between the local domain name system server and a data network name. When the terminal performs a service, it sends a local domain name system query message to the local domain name system server.

[0086] In this method, when a terminal performs a service, it can determine the local domain name system server used to access the service based on the received third-party correspondence, and then obtain the corresponding application server, thereby reducing satellite-to-ground interaction and lowering communication overhead.

[0087] In one possible implementation, the local domain name system server is deployed on the first satellite to which the terminal accesses; or, the local domain name system server is deployed on a second satellite, which is a satellite with the local domain name system server deployed and connected to the first satellite; or, the local domain name system server is deployed on a second satellite, which is a satellite with the local domain name system server deployed and is the closest to the first satellite.

[0088] In one possible implementation, the terminal sends a second message to the first satellite, requesting the address of a local domain name system server deployed on the first satellite. The terminal receives an RRC message from the first satellite, which includes a third mapping.

[0089] In one possible implementation, the third correspondence includes at least one of the following:

[0090] The mapping between one or more satellites, one or more data network names, and local domain name system servers;

[0091] The mapping between time, one or more data network names, and the local domain name system server;

[0092] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0093] In the above embodiments, the first correspondence is defined as the correspondence between satellites (such as the first satellite and other satellites), one or more data network names and the local domain name system server, or the correspondence between time (such as the current time and other times) and one or more data network names and the local domain name system server.

[0094] Fifthly, this application provides a communication device. This communication device may be a functional network element such as SMF / AMF / PCF, or a functional entity capable of implementing session management, access and mobility management, or policy control functions. In one possible implementation, the communication device has the functions described in the first aspect above. For example, the communication device includes modules, units, or means corresponding to the operations involved in the first aspect. These modules, units, or means can be implemented through software, hardware, or a combination of software and hardware.

[0095] In one possible implementation, the communication device includes a communication unit and a processing unit. The processing unit is used to determine a first server based on ephemeris information and the terminal's first location information. The first server includes a local domain name system server or one or more application servers corresponding to various services. The communication unit is used to send information about the first server to the terminal; the first server is associated with a first satellite accessed by the terminal.

[0096] In this embodiment, the communication device can determine the first server that provides the corresponding service to the terminal without the UE having to re-initiate the DNS process. Instead, the first server can be determined based on ephemeris information and the terminal's first location information, thus optimizing the UE's EAS reselection process, reducing satellite-to-ground interaction, and lowering communication overhead.

[0097] Optionally, other possible implementations of the fifth aspect can be referred to the descriptions of other possible implementations of the first aspect, which will not be repeated here.

[0098] Sixthly, this application provides a communication device. This communication device may be a terminal, or a device applied to a terminal (e.g., one or more processors, chips, or chip systems), or a device compatible with a terminal. In one possible implementation, the communication device has the functions described in the second aspect above. For example, the communication device includes modules, units, or means corresponding to the operations involved in the second aspect above. These modules, units, or means can be implemented through software, hardware, or a combination of software and hardware.

[0099] In one possible implementation, the communication device includes a communication unit and a processing unit. The processing unit, when the terminal initiates a first service, determines a second server based on a first correspondence. The second server includes an application server or a local domain name system server to be accessed; the application server or local domain name system server to be accessed is deployed on a satellite. The communication unit is used to access the second server.

[0100] In this embodiment, when initiating the first service, the communication device can determine the second server that provides the corresponding service to the terminal based on the first correspondence relationship. The UE does not need to re-initiate the DNS process, but can determine the second server based on the first correspondence relationship. This optimizes the process of the UE reselecting the EAS, thereby reducing satellite-to-ground interaction and reducing communication overhead.

[0101] Optionally, other possible implementations of the sixth aspect can be referred to the descriptions of other possible implementations of the second aspect, which will not be repeated here.

[0102] Seventhly, this application provides a communication device. The communication device may be a satellite, a functional entity performing related functions on a satellite, or an access network device deployed on a satellite. In one possible implementation, the communication device has the functions described in the third aspect above. For example, the communication device includes modules, units, or means corresponding to the operations involved in the third aspect. These modules, units, or means can be implemented through software, hardware, or a combination of both.

[0103] In one possible implementation, the communication device includes a communication unit and a processing unit. The processing unit is used to obtain a third correspondence; the third correspondence is the address of a local domain name system server, or the third correspondence includes a correspondence between the local domain name system server and a data network name; the local domain name system server is associated with a first satellite. The communication unit is used to transmit the third correspondence.

[0104] In this embodiment, the communication device can determine the third correspondence and send the third correspondence to the terminal, thereby optimizing the UE reselection EAS process, reducing satellite-to-ground interaction, and lowering communication overhead.

[0105] Optionally, other possible implementations of the seventh aspect can be referred to the descriptions of other possible implementations of the third aspect, which will not be repeated here.

[0106] Eighthly, this application provides a communication device. This communication device may be a terminal, or a device applied to a terminal (e.g., one or more processors, chips, or chip systems), or a device compatible with a terminal. In one possible implementation, the communication device has the functions described in the fourth aspect above. For example, the communication device includes modules, units, or means corresponding to the operations involved in the fourth aspect. These modules, units, or means can be implemented through software, hardware, or a combination of software and hardware.

[0107] In one possible implementation, the communication device includes a communication unit and a processing unit. The communication unit is used to receive a third mapping relationship, which is either the address of a local domain name system server or a mapping relationship between a local domain name system server and a data network name. The processing unit is used to send a local domain name system query message to the local domain name system server when performing business.

[0108] In this embodiment, when the communication device performs a service, it can determine the local domain name system server used to access the service based on the received third correspondence, and then obtain the corresponding application server, thereby reducing satellite-to-ground interaction and reducing communication overhead.

[0109] Optionally, other possible implementations of the eighth aspect can be found in the descriptions of other possible implementations of the fourth aspect, which will not be repeated here.

[0110] Ninthly, this application provides a communication device including a memory and one or more processors. The memory stores part or all of a computer program or instructions necessary for implementing the functions involved in at least one of the first to fourth aspects described above. The one or more processors are executable to carry out the computer program or instructions, which, when executed, cause the communication device to perform at least one of the following: the method of the first aspect and any possible implementation of the first aspect; the method of the second aspect and any possible implementation of the second aspect; the method of the third aspect and any possible implementation of the third aspect; and the method of the fourth aspect and any possible implementation of the fourth aspect. Optionally, the memory and the processor may be decoupled.

[0111] In one possible design, the communication device may also include interface circuitry, wherein the processor is used to communicate with other devices or components via the interface circuitry.

[0112] In one possible design, the communication device can be a terminal, or a communication module in the terminal, or a chip in the terminal that is responsible for communication functions, such as a modem chip or a SoC or SIP chip containing a modem module.

[0113] In a tenth aspect, this application provides a communication device, comprising: one or more processors and interface circuitry, wherein the interface circuitry is configured to receive signals from other communication devices and transmit them to the processor, or to send signals from the processor to other communication devices, and the processor, through logic circuitry or execution code instructions, is configured to implement at least one of the following: the method of the first aspect and any possible implementation thereof, the method of the second aspect and any possible implementation thereof, the method of the third aspect and any possible implementation thereof, and the method of the fourth aspect and any possible implementation thereof. Optionally, the communication device may be located on the network side.

[0114] In one aspect, this application provides a communication system comprising at least one of the means or apparatuses of the fourth to eighth aspects, such that the at least one means or apparatus performs at least one of the following: the method of the first aspect and any possible implementation of the first aspect, the method of the second aspect and any possible implementation of the second aspect, the method of the third aspect and any possible implementation of the third aspect, and the method of the fourth aspect and any possible implementation of the fourth aspect.

[0115] In a twelfth aspect, this application provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform at least one of the following: the method of the first aspect and any possible implementation of the first aspect, the method of the second aspect and any possible implementation of the second aspect, the method of the third aspect and any possible implementation of the third aspect, and the method of the fourth aspect and any possible implementation of the fourth aspect.

[0116] In a thirteenth aspect, this application provides a computer program product including instructions that, when executed on a computer, cause the computer to perform at least one of the following: the method of the first aspect and any possible implementation of the first aspect, the method of the second aspect and any possible implementation of the second aspect, the method of the third aspect and any possible implementation of the third aspect, and the method of the fourth aspect and any possible implementation of the fourth aspect.

[0117] In a fourteenth aspect, this application provides a chip including one or more processors (or logic circuits). Optionally, the chip may further include one or more communication interfaces (or interfaces) for implementing at least one of the following: the method of the first aspect and any possible implementation of the first aspect, the method of the second aspect and any possible implementation of the second aspect, the method of the third aspect and any possible implementation of the third aspect, and the method of the fourth aspect and any possible implementation of the fourth aspect. In one possible implementation, if the chip is the smallest processing unit in a complete machine, the chip may be one or more processors, or may include one or more processors and one or more memories, or may include one or more processors, one or more memories, and one or more transceivers for implementing at least one of the following: the method of the first aspect and any possible implementation of the first aspect, the method of the second aspect and any possible implementation of the second aspect, the method of the third aspect and any possible implementation of the third aspect, and the method of the fourth aspect and any possible implementation of the fourth aspect.

[0118] In a fifteenth aspect, this application provides a chip system. The chip system includes one or more processors and one or more interfaces. Optionally, it may also include memory for implementing at least one of the following: the methods of the first aspect and any possible implementation of the first aspect, the methods of the second aspect and any possible implementation of the second aspect, the methods of the third aspect and any possible implementation of the third aspect, and the methods of the fourth aspect and any possible implementation of the fourth aspect. The chip system may be composed of chips or may include chips and other discrete devices. Attached Figure Description

[0119] Figure 1 is a schematic diagram of a system architecture;

[0120] Figure 2 is a flowchart illustrating the first communication method provided in this application;

[0121] Figure 3 is a flowchart illustrating the second communication method provided in this application;

[0122] Figure 4 is a flowchart of Example 1 provided in this application;

[0123] Figure 5 is a flowchart of Example 2 provided in this application;

[0124] Figure 6 is a flowchart of Example 3 provided in this application;

[0125] Figure 7 is a flowchart illustrating the third communication method provided in this application;

[0126] Figure 8 is a flowchart of Example 4 provided in this application;

[0127] Figure 9 is a flowchart of Example 5 provided in this application;

[0128] Figure 10 is a schematic diagram of a communication device provided in this application;

[0129] Figure 11 is a schematic diagram of another communication device provided in this application. Detailed Implementation

[0130] For ease of understanding, the definitions of relevant terms used in this application are provided below:

[0131] Communication System: The communication method provided in this application can be applied to the system architecture shown in Figure 1. For example, this system architecture is based on EAS deployed on LEO satellites, which can enable rapid movement of LEO satellites covering the UE. As shown in Figure 1, the system architecture includes satellites (such as satellite 1 and satellite 2), terminals, and ground stations; for ease of description, it can be assumed that the radio access network (RAN), user plane function (UPF), and EAS are deployed on satellites, while network elements such as AMF, SMF, and DNS server are deployed on the ground. Optionally, this application does not limit the deployment method of each device and network element; for example, in addition to the deployment method shown in Figure 1, the RAN, UPF, and EAS may be deployed on LEO satellites, and the AMF, SMF, and DNS server may be deployed on medium Earth orbit (MEO) or geosynchronous orbit (GEO) satellites; there may also be multiple LEO satellites, which may be close or far apart, in which case the AMF, SMF, and DNS server may be deployed on one of the LEO satellites, and the AMF, SMF, and DNS server may be deployed on other LEO satellites that may be far apart. This application does not impose any limitations. Optionally, only access network equipment, only core network elements, or only EAS may be deployed on the satellite. This application does not impose any limitations.

[0132] In one possible implementation, the network architecture involved in this application can be a combination of mobile communication networks and satellites, such as a combination of a non-terrestrial network (NTN) and a satellite overall architecture (SAT_ARCH). For example, NTN includes two main scenarios: transparent forwarding and regenerative forwarding. This application mainly relates to the regenerative forwarding scenario. The regenerative payload is an effective payload that converts and amplifies the uplink radio frequency signal before it is transmitted on the downlink, including demodulation / decoding, encoding / modulation, etc., equivalent to having at least all or part of the base station functions on the satellite. The satellite with the regenerative payload can also have the functions of core network elements; for example, the satellite may have base stations and core network elements (such as RAN and UPF) deployed on it.

[0133] The communication system described in this application can include, but is not limited to, various radio access technologies (RATs), such as: Internet of Things (IoT) systems, narrowband IoT (NB-IoT) systems, reduced capability (RedCap) systems, IoT non-terrestrial networks (IoT NTN), 5G (or new radio, NR) communication systems, and transitional systems between LTE and 5G communication systems (also known as 4.5G systems). It can also be future communication systems, such as sixth-generation (6G) or even seventh-generation (7G) systems. The network architecture and business scenarios described in this application are for the purpose of more clearly illustrating the technical solutions of this application and do not constitute a limitation on the technical solutions provided in this application. Those skilled in the art will understand that with the evolution of communication network architectures and the emergence of new business scenarios, the technical solutions provided in this application are equally applicable to similar technical problems.

[0134] The terminal involved in this application can be referred to as a terminal device, which can be a device with wireless transceiver capabilities. It can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; it can also be deployed on water (such as ships); and it can be deployed in the air (such as airplanes, balloons, and satellites). The terminal device can be user equipment (UE), where UE includes handheld devices, vehicle-mounted devices, wearable devices, or computing devices with wireless communication capabilities. For example, the UE can be a mobile phone, tablet computer, or computer with wireless transceiver capabilities. The terminal device can also be a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in autonomous driving, a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in a smart city, a wireless terminal in a smart home, and so on. In this application, the device used to implement the terminal's functions can be the terminal itself; it can also be a device capable of supporting the terminal in implementing these functions, such as a chip system, which can be installed in the terminal. In this application, the chip system may be composed of chips or may include chips and other discrete devices. In the technical solution provided in this application, the device used to implement the functions of the terminal is a terminal, and the terminal is a UE (User Equipment) as an example to describe the technical solution provided in this application.

[0135] The network equipment involved in this application can be referred to as access network equipment, such as a base station (BS). A BS can be a device deployed in a wireless access network that can wirelessly communicate with terminals. Base stations may take various forms, such as macro base stations, micro base stations, relay stations, and access points. For example, the base station involved in this application can be a 5G base station or an evolved Node B (eNB) in LTE. The 5G base station can also be referred to as a transmission reception point (TRP) or a 5G base station (next-generation node B, gNB). In this application, the means for implementing the functions of the network equipment can be the network equipment itself; it can also be a means that supports the network equipment in implementing these functions, such as a chip system, which can be installed within the network equipment. In the technical solutions provided in this application, the means for implementing the functions of the network equipment is a network equipment, and the network equipment is a base station, as an example, to describe the technical solutions provided in this application.

[0136] The core network elements involved in this application may include, but are not limited to, devices or network elements such as AMF, SMF, UPF, PCF, edge application server discovery function (EASDF), EAS, and local DNS server. Among them, AMF is mainly responsible for access and mobility management in the mobile network, such as user registration management, connection management, and reachability management. Specific functions include non-access stratum signaling termination, registration area management, and access authentication. SMF is mainly responsible for session management in the mobile network, such as session establishment, modification, and release. Specific functions include assigning IP addresses to users and selecting UPFs to provide packet forwarding functions. PCF is used to support unified policy management of network behavior; provide policy rules to control plane functions for execution; and obtain subscription-related information from the unified data repository (UDR) function for policy decisions. UPF is mainly responsible for processing user packets, such as forwarding and billing statistics. In a session, the UPF directly connected to the data network (DN) via N6 is called the Protocol Data Unit (PDU) session anchor (PSA), and the UPF used for local traffic splitting is called the local PDU session anchor (L-PSA). The UPF acting as a splitting point is called a branching point (BP) or uplink classifier (ULCL). The EASDF is used to process DNS messages according to the instructions of the SMF; for example, the EASDF reports DNS messages to the SMF, adds ECS options and EDNS client-subnet options (where EDNS = extended mechanisms for DNS) to the DNS query, forwards the DNS query to the DNS server, and forwards the DNS response to the UE, etc. The local DNS server will prioritize returning the EAS IP address closest to it. For example, in this application, the local DNS server can be deployed on a satellite. When the local DNS server receives a DNS request message, it will prioritize replying with the address of the EAS deployed on the same satellite.

[0137] The process of discovering EAS using EASDF (see standard protocol 3GPP TS23.548 for details): In edge computing (EC) deployment scenarios, certain services may be provided by multiple EAS deployed at the network edge. These EAS provide the same services and content but have different IP addresses. When a UE needs to access this service, EC scenarios require it to access the nearest available EAS. Therefore, the UE needs to initiate a DNS procedure to obtain the appropriate EAS's IP address.

[0138] In future network deployments, the EAS (Electronic Access Controller) may be deployed on LEO satellites and provide services to UEs (User Equipment) on the ground. However, LEO satellites move at high speeds relative to the ground, and the coverage time for a stationary UE is only about 3-5 minutes. This necessitates frequent EAS replacements for UEs. In one possible implementation, replacing the EAS requires the UE to re-initiate the DNS process. If the DNS server is deployed on the ground, frequent satellite-to-ground interactions are required, increasing communication overhead. Another possible implementation is that if the UE does not replace the EAS, it can connect to the previous EAS via inter-satellite links. However, this approach may lead to increased latency and compromise service quality.

[0139] Therefore, this application provides a communication method that can optimize the UE's EAS reselection process in scenarios where the EAS is deployed on LEO and the UE frequently switches EAS, thereby reducing satellite-to-ground interaction.

[0140] For example, Figure 2 is a flowchart of the first communication method provided in this application. This method is implemented through the interaction between a first network element and a terminal. For example, the first network element is located on the network side and may be a functional network element such as SMF, AMF, or PCF, or a functional entity capable of implementing session management functions, access and mobility management functions, or policy control functions. The terminal may be a terminal device or its components, or a chip or circuit applied to the terminal. The method includes the following steps:

[0141] S101, the first network element determines the information of the first server based on the ephemeris information and the first location information of the terminal.

[0142] In one possible implementation, ephemeris information is used to indicate the satellite's position or coverage status. For example, this ephemeris information can be information about the satellite's motion patterns, such as orbital parameters, angular velocity, and speed. Based on this information, communication equipment can calculate the satellite's position in its orbit at each moment. Ephemeris information can be represented as a simple correspondence, such as the satellite's position information corresponding to each moment / time period. Ephemeris information can also be represented as a satellite coverage map, such as satellite coverage availability information. A satellite coverage map divides the Earth's surface into multiple grid points and shows 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.

[0143] Optionally, the ephemeris information involved in this application includes, but is not limited to, traditional ephemeris information, satellite map information, and gateway station deployment information. 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, velocity, and other states. 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, perigee distance, etc.). 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 definitions of ephemeris information in existing protocols. For example, in this application, ephemeris information can also be referred to as satellite coverage availability information.

[0144] In one possible implementation, the terminal's first location information is used to indicate the terminal's current geographical location; for example, the terminal's first location information includes the terminal's current latitude and longitude information, thereby indicating the terminal's current geographical location.

[0145] In one possible implementation, the first network element determines the information of the first server based on ephemeris information and the terminal's first location information. Specifically, the first network element determines the grid points covered and uncovered by satellites on the Earth's surface in each time period based on the satellite coverage map in the ephemeris information; then, based on the terminal's first location information, it determines which satellites among the grid points covering the terminal in each time period can provide services to the terminal, thereby determining the information of the first server or the first correspondence. For ease of description, this application refers to the satellite that can provide services to the terminal as the first satellite, or the satellite that provides services to the terminal as the satellite accessed by the terminal, i.e., the satellite accessed by the terminal is referred to as the first satellite. Optionally, the satellite accessed by the terminal can be the satellite on which the RAN accessed by the terminal is deployed; for example, the first satellite can be the satellite on which the RAN accessed by the terminal is deployed (i.e., the RAN is deployed on a satellite). Optionally, the information of the first server and the first correspondence can be interchangeable. For example, S101 can also be described as: the first network element determines the first correspondence based on ephemeris information and the terminal's first location information.

[0146] In one possible implementation, the first server includes a local domain name system server (such as a local DNS server) or one or more application servers corresponding to the service (such as EAS). The first server is associated with the first satellite accessed by the terminal. Optionally, the local DNS server can be replaced with DNS server, or other names, whose function is to return the address of a server located near it; this application does not limit the name of the server with this function. Specifically, the association between the first server and the first satellite accessed by the terminal can include, but is not limited to, the following relationships:

[0147] (1) The first server is deployed on the first satellite. For example, a local DNS server or one or more service-related EASs are deployed on the first satellite. If a terminal accesses the first satellite, the local DNS server or one or more service-related EASs on the first satellite can provide the corresponding services to the terminal. Optionally, providing corresponding services to the terminal may involve the local DNS server providing DNS query services to the terminal so that the terminal can obtain the EAS address (EAS IP), or one or more service-related EASs providing service and content services to the terminal.

[0148] (2) The first server is deployed on the second satellite, which is a satellite that has deployed an application server or a local domain name system server and is connected to the first satellite. For example, suppose a terminal connects to the first satellite, but the first satellite does not deploy a local DNS server or one or more service-related EASs; then, in order to provide the corresponding service to the terminal, the first satellite can obtain information from a satellite connected to the first satellite that has deployed a local DNS server or one or more service-related EASs (i.e., the second satellite), and provide the corresponding service to the terminal through the local DNS server or one or more service-related EASs on the second satellite. Here, "connected to the first satellite" can mean that there is an inter-satellite link between the second satellite and the first satellite; or, the second satellite and the first satellite can communicate through one-hop or multi-hop inter-satellite links. For example, suppose both the second satellite and the first satellite are connected to a certain satellite through an inter-satellite link, then the second satellite and the first satellite can communicate through that satellite.

[0149] (3) The first server is deployed on the second satellite, which is the satellite that has deployed the application server or the local domain name system server and is closest to the first satellite. For example, suppose the terminal connects to the first satellite, but the first satellite has not deployed a local DNS server or one or more service-related EASs; then in order to provide the corresponding service to the terminal, the first satellite can obtain the satellite that has deployed a local DNS server or one or more service-related EASs among the satellites closest to the first satellite (that is, the second satellite), and provide the corresponding service to the terminal through the second satellite. Optionally, the second satellite being closest to the first satellite may mean that the second satellite has deployed a local DNS server or one or more service-related EASs, and the second satellite and the first satellite meet one or more of the following conditions: minimum number of inter-satellite link hops, shortest physical distance, lowest transmission latency, located in the same orbit, located in the same constellation, etc.; for example, the second satellite has the minimum number of inter-satellite link hops with the first satellite, or the second satellite has the lowest transmission latency with the first satellite, etc., which are not limited in this application. The closest distance between the second satellite and the first satellite can be the shortest straight-line distance between them (e.g., shorter than the distance between the second satellite and the first satellite and all other satellites in the same constellation); or the fewest inter-satellite link hops between the second satellite and the first satellite (e.g., fewer than the number of inter-satellite link hops between the second satellite and the first satellite and all other satellites in the same constellation).

[0150] It is understood that the aforementioned first or second satellite may be a LEO satellite, MEO satellite, GEO satellite, or NGSO satellite, etc., and this application does not limit it.

[0151] In one possible implementation, before the first network element determines the information of the first server based on ephemeris information and the terminal's first location information, the first network element can determine that the terminal accesses via a non-terrestrial network. For example, non-terrestrial network access can be at least one of the following: satellite access, regenerable satellite access, NGSO satellite access, LEO satellite access, or UAV access, etc., which are not limited in this application. Optionally, the first network element determines that the terminal accesses via a non-terrestrial network by determining that the RAN node ID accessed by the UE corresponds to non-terrestrial network access based on the RAN node ID accessed by the UE and the correspondence between different RAN node IDs and access types configured locally by the first network element. Optionally, the first network element determines that the terminal accesses via a non-terrestrial network by receiving first indication information, which is used to indicate that the terminal accesses the first satellite; specifically, the first indication information is used to indicate the RAN node ID and / or satellite ID corresponding to the first satellite. If the first network element receives the satellite ID, or if the first webpage can determine the corresponding satellite ID based on the RAN node ID accessed by the UE, then it is determined that the RAN node ID accessed by the UE corresponds to non-terrestrial network access. For example, assuming the first network element is an AMF, when a terminal initiates a session establishment procedure, the AMF receives a session establishment request message and can determine the first satellite the terminal is accessing based on its local configuration or the RAN node ID accessed by the terminal (e.g., determining the satellite ID of the first satellite). In this case, the first indication information could be the session establishment request message. As another example, assuming the first network element is an SMF, when a terminal initiates a session establishment procedure, the AMF receives a session establishment request message and can determine the first satellite the terminal is accessing based on its local configuration or the RAN node ID accessed by the terminal (e.g., determining the satellite ID of the first satellite). Then, the AMF sends a session context establishment request message to the SMF. This session context establishment request message can include the satellite ID of the first satellite, and in this case, the first indication information could be the session context establishment request message.

[0152] In one possible implementation, the first network element determines a first correspondence based on ephemeris information and the terminal's first location information. For example, the first network element can determine the first correspondence based on one or more of the following: the first location information, the terminal's first service information, the first satellite, and the ephemeris information. In this implementation, the first correspondence may include information about the first server. That is, the first network element determining the first correspondence based on ephemeris information and the terminal's first location information can replace the operation of the first network element determining the first server based on ephemeris information and the terminal's first location information; determining the first correspondence is equivalent to determining the information about the first server.

[0153] In one possible implementation, the first correspondence may include one or more of the following:

[0154] (1) The correspondence between one or more satellites and local domain name system servers, wherein one or more satellites include the first satellite. For example, suppose the first satellite is represented as satellite #1, and satellite #1 can be associated with a local DNS server, and suppose the local DNS server IP is represented as 192.aaa; optionally, one or more satellites may also include other satellites (such as satellite #2, and satellite #2 can be associated with a local DNS server, and suppose the local DNS server IP is represented as 192.bbb), then the first correspondence includes the correspondence between one or more satellites and local domain name system servers, as shown in Table 1.

[0155] Table 1: The correspondence between one or more satellites and local domain name system servers.

[0156] It is understood that Table 1 is only one example and may include more satellites and associate more local DNS servers, which is not limited in this application.

[0157] (2) The correspondence between one or more satellites, one or more data network names, and local domain name system servers, wherein one or more satellites include the first satellite. For example, assume the first satellite is represented as satellite #1, and assume satellite #1 can be associated with one or more local DNS servers, and assume the IP of the one or more local DNS servers is represented as 192.mmm, 192.nnn, etc. It should be noted that one satellite is associated with multiple local domain name system servers because multiple local domain name system servers have different characteristics, such as corresponding to different DNNs; and assume that different DNNs are represented as DNN#1, DNN#2, etc. Optionally, one or more satellites may also include other satellites (such as satellite #2, and satellite #2 can be associated with one or more local DNS servers, and assume the IP of the one or more local DNS servers is represented as 192.aaa, 192.bbb, etc.). Then the first correspondence includes the correspondence between one or more satellites, one or more data network names, and local domain name system servers, as shown in Table 2.

[0158] Table 2: Correspondence between one or more satellites, one or more data network names and local domain name system servers.

[0159] It is understood that Table 2 is only one example and may include more satellites, associated with more local DNS servers and DNNs, which is not limited in this application.

[0160] (3) The correspondence between one or more satellites, one or more service domain names, and the application servers corresponding to the one or more service domain names, wherein the one or more satellites include the first satellite, and the one or more service domain names include the service domain name of the first service (also called the first service domain name). Different services (assuming they include the first service, the second service, etc.) can be distinguished by different FQDNs; for example, the first service can be represented by the FQDN www.xxx.com, and the second service can be represented by the FQDN www.yyy.com. For example, the first satellite is represented as satellite #1, and satellite #1 can be associated with one or more EASs, assuming that the IP of the one or more EASs is represented as 192.mmm, 192.nnn, etc. It should be noted that one satellite is associated with multiple servers because the multiple servers have different characteristics, such as corresponding to different FQDNs, DNNs, etc. Optionally, one or more satellites may also include other satellites (such as satellite #2, and satellite #2 can be associated with one or more EASs, assuming that the IP of the one or more EASs is represented as 192.aaa, 192.bbb, etc.). Assuming that one or more business domain names include a first business domain name and a second business domain name, and different satellites can be associated with the same business domain name, then the first correspondence includes the correspondence between one or more satellites, one or more business domain names and the application servers corresponding to the one or more business domain names, as shown in Table 3.

[0161] Table 3: The correspondence between one or more satellites, one or more business domain names and the application servers corresponding to the one or more business domain names.

[0162] It is understood that Table 3 is only one example, and satellite #1 can be associated with more EAS servers, which are not shown in Table 3. According to Table 3, the correspondence between the first satellite and the application server corresponding to the first service can be that satellite #1 corresponds to the FQDN (www.xxx.com) of the first service, thus corresponding to the EAS IP (192.mmm). A satellite can be associated with one or more EAS servers, and the multiple servers associated with a satellite can have different characteristics, such as corresponding to different FQDNs, DNNs, etc. Therefore, Table 3 can also include more satellites, as well as the service domain names and application servers associated with the satellites; this application does not impose any limitations on this.

[0163] (4) The correspondence between one or more satellites, one or more data network names, one or more service domain names, and the application servers corresponding to the one or more service domain names, wherein one or more satellites include the first satellite, and one or more service domain names include the service domain name of the first service. For example, assume that the first satellite is represented as satellite #1, and satellite #1 can be associated with one or more EAS, and assume that the one or more EAS IPs are represented as 192.mmm, 192.nnn, etc.; wherein, different services (assuming that they include the first service, the second service, etc.) can be distinguished by different FQDNs; for example, the first service can be represented by the FQDN www.xxx.com, and the second service can be represented by the FQDN www.yyy.com. And assume that the first service information includes one or more DNNs, and the one or more DNNs are represented as DNN#1, DNN#2, etc., then the first correspondence includes the correspondence between one or more satellites, one or more data network names, one or more service domain names, and the application servers corresponding to the one or more service domain names, as shown in Table 4.

[0164] Table 4: The correspondence between one or more satellites, one or more data network names, one or more business domain names and the application servers corresponding to the one or more business domain names.

[0165] It is understood that Table 4 is only one example, and satellite #1 or satellite #2 can be associated with more EAS servers and DNNs, which is not limited in this application.

[0166] (5) The correspondence between time and local domain name system servers, where time includes the current moment. Optionally, time also includes the first time, which is the time when the first satellite provides services to the terminal, for example, the current moment. For example, suppose the time includes time #1 (which can be any time period in 24 hours, such as 9:00 to 9:10) and time #2 (such as 9:10 to 9:20), and time #1 can be associated with a local DNS server, assuming the local DNS server IP is represented as 192.aaa; time #2 can be associated with a local DNS server, assuming the local DNS server IP is represented as 192.bbb; then the first correspondence includes the correspondence between time and local domain name system servers, as shown in Table 5.

[0167] Table 5: Correspondence between time and local domain name system server.

[0168] It is understood that Table 5 is only one example, and Table 5 may include other times, with different times associated with different local domain name system servers, which is not limited in this application.

[0169] (6) The correspondence between time, one or more data network names, and local domain name system servers. For example, suppose the time includes time #1 (e.g., 9:00~9:10) and time #2 (e.g., 9:10~9:20), and suppose time #1 can be associated with one or more local DNS servers, and suppose the IP of these one or more local DNS servers is represented as 192.mmm, 192.nnn, etc. It should be noted that one time is associated with multiple local domain name system servers because multiple local domain name system servers have different characteristics, such as corresponding to different DNNs. Optionally, suppose time #2 can be associated with one or more local DNS servers, and suppose the IP of these one or more local DNS servers is represented as 192.aaa, 192.bbb, etc. Then the first correspondence includes the correspondence between time, one or more data network names, and local domain name system servers, as shown in Table 6.

[0170] Table 6: The correspondence between a time, one or more data network names, and the local domain name system server.

[0171] It is understood that Table 6 is only one example and may include more time periods, more local DNS servers and DNNs associated, which is not limited in this application.

[0172] (7) The correspondence between time, one or more business domain names, and the application servers corresponding to one or more business domain names. For example, the first business can be represented by FQDN www.xxx.com, and the second business can be represented by FQDN www.yyy.com. For example, assuming that time includes time #1 (e.g., 9:00~9:10) and time #2 (e.g., 9:10~9:20), and assuming that time #1 can be associated with one or more EAS, and assuming that the IP of one or more EAS is represented as 192.mmm, 192.nnn, etc., it should be noted that one time is associated with multiple application servers because multiple application servers have different characteristics, such as corresponding to different FQDNs. Optionally, assuming that time #2 can be associated with one or more EAS, and assuming that the IP of one or more EAS is represented as 192.aaa, 192.bbb, etc., then the first correspondence includes the correspondence between time, one or more business domain names, and the application servers corresponding to one or more business domain names, as shown in Table 7.

[0173] Table 7: Correspondence between time, one or more business domain names, and the application servers corresponding to one or more business domain names.

[0174] It is understood that Table 7 is only one example, and time #1 or time #2 can be associated with more EAS servers, which is not limited in this application. According to Table 7 above, the correspondence between the first time and the application server corresponding to the first service can be that time #1 (9:00~9:10) corresponds to the FQDN (www.xxx.com) of the first service, and thus corresponds to the EAS IP (192.mmm).

[0175] (8) The correspondence between time, one or more data network names, one or more service domain names, and the application servers corresponding to the one or more service domain names. For example, assume that time includes time #1 (e.g., 9:00~9:10) and time #2 (e.g., 9:10~9:20), and assume that time #1 can be associated with one or more EAS, and assume that the IP of the one or more EAS is represented as 192.mmm, 192.nnn; and assume that time #1 can be associated with one or more EAS, and assume that the IP of the one or more EAS is represented as 192.aaa, 192.bbb. Assuming that the first service information includes one or more DNNs, and the one or more DNNs are represented as DNN#1, DNN#2, etc., then the first correspondence includes the correspondence between time, one or more data network names, one or more service domain names, and the application servers corresponding to the one or more service domain names, as shown in Table 8.

[0176] Table 8: Correspondence between time, one or more data network names, one or more business domain names and the application servers corresponding to the one or more business domain names.

[0177] It is understood that Table 8 is only one example, and more time periods (such as time #3, time #4, etc.) can be included to associate more EAS and DNN, which is not limited in this application.

[0178] S102, the first network element sends information from the first server to the terminal; correspondingly, the terminal receives information from the first server.

[0179] For example, assuming the first network element is an SMF, the SMF can send information about the first server (such as the local DNS server IP or EAS IP) to the terminal via the AMF or the first satellite (assuming the RAN is deployed on the first satellite). Alternatively, assuming the first network element is an AMF, the AMF can send information about the first server (such as the local DNS server IP or EAS IP) to the terminal via the first satellite (assuming the RAN is deployed on the first satellite). Optionally, the specific message carrying the information about the first server will be described in detail in the following embodiments.

[0180] In one possible implementation, if the first network element determines a first correspondence, then in S102, the first network element sends the first correspondence to the terminal. For example, assuming the first network element is an SMF, the SMF can send the first correspondence to the terminal through the AMF or the first satellite (assuming the RAN is deployed on the first satellite).

[0181] Optionally, in addition to the examples and extended descriptions in Tables 1 to 8 above, the first correspondence can also involve one satellite or one time point corresponding to the addresses of multiple servers. For example, suppose the first correspondence shown in Table 1 can be extended as shown in Table 9:

[0182] Table 9: The correspondence between one or more satellites and local domain name system servers.

[0183] In this application, it is assumed that satellite #1 can be associated with two local DNS server IPs, and satellite #2 can also be associated with two local DNS server IPs. Correspondingly, the terminal receives this first correspondence. Assuming the terminal is connected to satellite #1, based on this first correspondence, the terminal can determine the two local DNS server IPs corresponding to satellite #1, and then determine, based on its own logic, which local DNS server IP to transmit services to. This application does not limit the specific determination method.

[0184] In this embodiment, the first network element can be determined as the first server (e.g., local DNS server or EAS) or the first correspondence that provides the corresponding service to the terminal, and the first server can be determined without the UE re-initiating the DNS process. This optimizes the process of the UE reselecting the EAS, thereby reducing satellite-to-ground interaction and lowering communication overhead.

[0185] For example, Figure 3 is a flowchart illustrating the second communication method provided in this application. This method is executed by a terminal, which may be a terminal device or its components, or a chip or circuit applied to the terminal. The method includes the following steps:

[0186] S201, When the terminal initiates the first service, the terminal determines the second server based on the first correspondence.

[0187] In one possible implementation, the first service includes, but is not limited to, DNS query service and EAS discovery service. For example, a terminal can initiate a DNS query service through a DNS request to request and obtain the corresponding local DNS server. As another example, a terminal can use EASDF to assist in discovering the EAS IP address, thereby obtaining the corresponding EAS.

[0188] In one possible implementation, the second server includes the application server to be accessed or the local domain name system server; the application server to be accessed or the local domain name system server is deployed on a satellite. For example, when the terminal initiates the first service, it indicates that it needs to access the EAS corresponding to the first service, so the second server includes the EAS to be accessed or the local DNS server (the EAS corresponding to the first service is queried through the local DNS server).

[0189] In one possible implementation, the first correspondence can refer to the corresponding description in S101, such as the corresponding description in Tables 1 to 8, which will not be repeated here.

[0190] In one possible implementation, the terminal determines the second server based on the first correspondence. Specifically, the terminal determines the second server based on the first correspondence, the first service, the terminal's first location information, and ephemeris information. For example, assuming the first correspondence is as shown in Table 1, and the terminal determines access satellite #1 based on the first location information and ephemeris information, then based on the first correspondence, the second server can be determined to include local DNS server IPs 192.aaa and 192.aaa. It is understood that the terminal ultimately needs to determine which EAS can provide the first service to the terminal (refer to the process and example of EAS discovery using EASDF in the standard protocol 3GPP TS23.548). Therefore, the terminal can send a DNS query message to the aforementioned local DNS server IP, which can carry the FQDN of the first service. Correspondingly, the local DNS server can carry the EAS IP corresponding to the FQDN of the first service in its DNS response message (here, the responding local DNS server refers to the local DNS server that can find the EAS IP corresponding to the FQDN of the first service). Optionally, when the first correspondence is as shown in Tables 2 to 4, the process by which the terminal determines the second server based on the first correspondence, the first service, the terminal's first location information, and ephemeris information is similar to the example above. For example, assuming the first correspondence is as shown in Table 2, the terminal determines the access satellite #1 based on the first location information and ephemeris information, and can determine the FQDN of the first service (such as www.xxx.com), then the terminal can determine the corresponding EAS IP as 192.mmm. Other examples related to Tables 3 or 4 are similar and will not be elaborated here.

[0191] In one possible implementation, the second server is a server deployed on either the first or second satellite. The second satellite is one that deploys an application server or a local domain name system server and is connected to the first satellite; or, the second satellite is one that deploys an application server or a local domain name system server and is closest to the first satellite. Examples of the second satellite can be found in the description of the second satellite in S101, and will not be repeated here. It is understood that the second server in this embodiment and the first server in the embodiment of Figure 2 may be the same server. For example, the first server determined by the first network element ephemeris information and the terminal's first location information and the second server determined by the terminal based on the first correspondence may be the same server. Alternatively, the second server and the first server may not be the same server. For example, the first server determined by the first network element ephemeris information and the terminal's first location information may correspond to a first time (e.g., 9:00–9:10), and the second server may correspond to a second time (e.g., 9:10–9:20). After receiving the correspondence (e.g., at 9:00), the terminal may not immediately access the service. Instead, if the service is accessed after a certain period of time (e.g., access is determined at 9:15), then the second server determined by the terminal is the server corresponding to the second time (e.g., 9:10 to 9:20), which is different from the first server. This application does not limit this.

[0192] S202, the terminal accesses the second server.

[0193] Access can occur through the terminal sending data packets to the EAS or sending a DNS query message to a DNS server. For example, if the second server is the EAS, when the UE determines to access a service (e.g., the user clicks on an app, and the app corresponds to an FQDN), the UE does not need to initiate a DNS query process but directly accesses the second server, for example, by sending a service data packet to the EAS IP address of that second server. Alternatively, if the second server is a local DNS server, when the UE determines to access a service, the UE sends a DNS query message (including the accessed FQDN) to the local DNS server IP address. The local DNS server will carry the EAS IP address deployed on the satellite currently accessed by the UE in its DNS response message. After receiving this DNS response message, the UE can access the second server, for example, by sending a service data packet to that EAS IP address.

[0194] In this embodiment, when the terminal initiates the first service, it can determine the second server (e.g., local DNS server or EAS) that provides the corresponding service to the terminal based on the first correspondence. The UE does not need to re-initiate the DNS process, but can determine the second server based on the first correspondence. This optimizes the process of the UE reselecting the EAS, thereby reducing satellite-to-ground interaction and reducing communication overhead.

[0195] The following will detail the specific implementation methods for extending the embodiments shown in Figures 2 and 3 and applying them to optimize the UE reselection of EAS process through several specific examples.

[0196] Example 1: In the session establishment / modification process, the first network element sends the first correspondence to the UE; the UE accesses the network based on the first correspondence and optimizes the UE reselection EAS process to reduce satellite-to-ground interaction. For example, Figure 4 is a schematic diagram of the process of Example 1 provided in this application. This process can be implemented by the interaction between the UE, AMF, SMF (in this embodiment, the SMF can implement the functions of the first network element in the embodiments of Figures 2 and 3), and a second server (such as EAS or local DNS server), including the following steps:

[0197] S301, the terminal sends a session establishment request message to the AMF; correspondingly, the AMF receives the session establishment request message.

[0198] In one possible implementation, the session establishment request message includes information about the first satellite the terminal is accessing. For example, the terminal could directly send information about the first satellite it is accessing (such as the satellite ID) to the AMF.

[0199] In one possible implementation, the AMF can determine the satellite ID based on local configuration or the RAN accessed by the UE. For example, the session establishment request message includes information about the RAN accessed by the terminal (such as the RAN node ID). Based on this RAN node ID, the AMF can determine that the RAN is deployed on the first satellite, thereby obtaining the satellite ID of the first satellite.

[0200] In one possible implementation, the terminal sends a session establishment request message to the AMF, specifically, the terminal can send the session establishment request message to the AMF via the RAN. Optionally, the session establishment request message can be a PDU session establish request.

[0201] S302, AMF sends a session context establishment request message to SMF; correspondingly, SMF receives the session context establishment request message.

[0202] In one possible implementation, the session context establishment request message includes information about the first satellite. For example, the session context establishment request message may include the satellite ID of the first satellite.

[0203] S303, SMF determines the first correspondence based on one or more of the terminal's first location information, the terminal's first service information, the first satellite, and ephemeris information.

[0204] In one possible implementation, the first service information includes at least one of the following: data network name (DNN), network slice selection assistance information (NSSAI), and service domain name. Here, DNN refers to different networks; for example, the internet is one DNN, and a company's intranet is another. Each UE session can only correspond to one DNN. If the UE establishes multiple sessions, sessions corresponding to different DNNs access different services. Specifically, NSSAI can be single network slice selection assistance information (S-NSSAI), which connects the terminal to the corresponding network slice based on the service requirements. The service domain name (FQDN) can be referred to the description in the previous embodiments and will not be repeated here.

[0205] Specifically, S303 includes, but is not limited to, the following specific implementation methods:

[0206] Implementation Method 1: Based on the first location information, the first satellite, and the first service information, the SMF determines the first correspondence, including: the correspondence between one or more satellites and the local domain name system server, and the correspondence between one or more satellites, one or more service domain names, and the application servers corresponding to one or more service domain names. The one or more satellites include the first satellite.

[0207] For example, suppose the first satellite is represented as satellite #1, and satellite #1 can be associated with a local DNS server. Suppose the IP of this local DNS server is represented as 192.aaa, etc., then the first correspondence is shown in Table 1, which will not be elaborated here.

[0208] For example, one or more service domain names may include the FQDN of the first service, the FQDN of the second service, etc., where the FQDN of the first service is represented as www.xxx.com, and the FQDN of the second service is represented as www.yyy.com. For instance, one or more satellites include satellite #1 and satellite #2, and satellite #1 can be associated with one or more EASs (different EASs correspond to different FQDNs), assuming the IPs of these one or more EASs are represented as 192.mmm, 192.nnn, etc., and satellite #2 can be associated with one or more EASs (different EASs correspond to different FQDNs), assuming the IPs of these one or more EASs are represented as 192.aaa, 192.bbb, etc., then the first correspondence is shown in Table 3, and will not be elaborated further here. Optionally, one or more service domain names may include all FQDNs of EAS deployments located near the UE; wherein, all FQDNs near the UE can be determined based on EAS deployment information and the first location information.

[0209] Implementation Method 2: Based on the first location information, the first satellite, ephemeris information, and the first service information, SMF determines the first correspondence, including: the correspondence between time and the local domain name system server, or the correspondence between time, one or more service domain names, and the application server corresponding to one or more service domain names.

[0210] For example, suppose the time includes time #1 (e.g., 9:00~9:10) and time #2 (e.g., 9:10~9:20), and time #1 can be associated with a local DNS server, assuming the local DNS server IP is represented as 192.aaa; time #2 can be associated with a local DNS server, assuming the local DNS server IP is represented as 192.bbb; then the first correspondence is shown in Table 5, which will not be elaborated here.

[0211] For example, one or more business domain names may include the FQDN of the first business, the FQDN of the second business, etc., where the FQDN of the first business is represented as www.xxx.com, and the FQDN of the second business is represented as www.yyy.com. For instance, suppose the time includes time #1 (e.g., 9:00~9:10) and time #2 (e.g., 9:10~9:20), and time #1 can be associated with a local DNS server, assuming the IP address of this local DNS server is 192.aaa; time #2 can be associated with a local DNS server, assuming the IP address of this local DNS server is 192.bbb; then the first correspondence is shown in Table 7, and will not be elaborated further here.

[0212] Optionally, the first correspondence determined by the SMF in S303 may include different tables from those in Embodiment 1 and Embodiment 2, for example, corresponding to different FQDNs. This application does not limit the specific form of the first correspondence; for example, other table forms may be used to represent the first correspondence, as long as they can reflect the above-mentioned first correspondence.

[0213] S304, SMF sends the first correspondence to the terminal; correspondingly, the terminal receives the first correspondence.

[0214] In one possible implementation, when the first correspondence determined by the SMF includes different information, the first correspondence sent by the SMF to the terminal will also be different. For example, when the first correspondence determined by the SMF is as shown in Table 1, the first correspondence sent by the SMF to the terminal can be Table 1. As another example, when the first correspondence determined by the SMF is as shown in Table 3, the first correspondence sent by the SMF to the terminal can be Table 3.

[0215] Optionally, the SMF sends the first correspondence to the terminal. Specifically, the SMF may send the first correspondence to the terminal through the AMF and / or RAN.

[0216] In one possible implementation, the first correspondence is carried in a first message, which can be any of the following: a session establishment acceptance message or a session modification instruction. For example, when the SMF sends the first correspondence to the terminal, it can be that the SMF sends a first message to the terminal. This first message can be a session establishment acceptance message (also known as a session context creation message (such as Nsmf_PDUSession_CreateSMContext Request)) or a session modification instruction, and the first message includes the first correspondence.

[0217] S305, when the terminal initiates the first service, the terminal determines the second server based on the first correspondence.

[0218] In one possible implementation, the terminal determines the second server based on the first correspondence. Specifically, the terminal determines the second server based on the first correspondence, the first service, the terminal's first location information, and ephemeris information. For example, assuming the first correspondence is as shown in Table 1, and the terminal determines the access satellite #1 based on the first location information and ephemeris information, then based on the first correspondence, the second server can be determined to be the local DNS server with the local DNS server IP address 192.aaa. It is understood that the terminal ultimately needs to determine which EAS can provide the first service to the terminal. Therefore, the terminal can send a DNS query message to the aforementioned local DNS server IP address, which can carry the FQDN of the first service. Correspondingly, the local DNS server can carry the EAS IP address corresponding to the FQDN of the first service in its DNS response message (here, the responding local DNS server refers to the local DNS server that can find the EAS IP address corresponding to the FQDN of the first service). Optionally, when the first correspondence is as shown in Tables 2 to 8, the process by which the terminal determines the second server based on the first correspondence is similar to the example above. For example, assuming the first correspondence is as shown in Table 3, the terminal determines the access satellite #1 based on the first location information and ephemeris information, and can determine the FQDN of the first service (such as www.xxx.com), then the terminal can determine the corresponding EAS IP as 192.mmm. Other examples of the aforementioned first correspondence are similar and will not be repeated here.

[0219] S306, the terminal accesses the second server.

[0220] For example, if the second server is an EAS (Electronic Access System), when the UE determines to access a service (e.g., the user clicks on an app, and the app corresponds to an FQDN), the UE does not need to initiate a DNS query process. Instead, it directly accesses the second server, for example, by sending service data packets to the EAS IP address of that second server. Alternatively, if the second server is a local DNS server, when the UE determines to access a service, the UE sends a DNS query message (including the accessed FQDN) to that local DNS server IP address. The local DNS server will carry the EAS IP address deployed on the satellite currently accessing the UE in its DNS response message. After receiving this DNS response message, the UE can access the second server, for example, by sending service data packets to that EAS IP address.

[0221] Optionally, following S306, the following steps are also included:

[0222] S307, when the terminal switches to the third satellite, the terminal determines the third server based on the first correspondence.

[0223] In one possible implementation, even if the UE is not moving, the terminal may switch to a third satellite that is different from the first satellite due to the high speed of the satellite relative to the ground.

[0224] In one possible implementation, the terminal determines the third server based on the first correspondence. Specifically, the terminal determines the third server based on the first correspondence, the first service, the terminal's first location information, and ephemeris information. A specific example can be found in the description of determining the second server in S305. The difference is that the terminal is currently connected to a third satellite (e.g., satellite #2). In this case, the terminal can determine the third server based on the first correspondence (e.g., Tables 1 to 8). For example, based on Table 3, the terminal switches to satellite #2 and can determine the FQDN of the first service (e.g., www.xxx.com). Therefore, the terminal can determine the corresponding EAS IP as 192.aaa.

[0225] In one possible implementation, the third server includes a local domain name system server or an application server corresponding to one or more services, and the third server is associated with the third satellite after the terminal switches. For example, after the terminal switches to the third satellite, if the terminal initiates the first service again, the terminal needs to re-determine the third server based on the first correspondence. Specifically, the association between the third server and the third satellite after the terminal switches can include, but is not limited to, the following types of associations:

[0226] (1) The third server is deployed on the third satellite. For example, the local DNS server or one or more services corresponding to the EAS are deployed on the third satellite. If the terminal switches to the third satellite, the local DNS server or one or more services corresponding to the EAS on the third satellite can provide the corresponding services to the terminal.

[0227] (2) The third server is deployed on the fourth satellite, which is a satellite that has deployed an application server or a local domain name system server and is connected to the third satellite. For example, suppose the terminal switches to the third satellite, but the third satellite does not have a local DNS server or one or more service-related EAS deployed on it; then, in order to provide the corresponding service to the terminal, the third satellite can obtain information from a satellite connected to it that has deployed a local DNS server or one or more service-related EAS deployed on it (i.e., the fourth satellite), and provide the corresponding service to the terminal through the local DNS server or one or more service-related EAS on the fourth satellite. The connection between the fourth satellite and the third satellite can mean that there is an inter-satellite link between the fourth satellite and the third satellite; or, the fourth satellite and the third satellite can communicate through one-hop or multi-hop inter-satellite links. For example, suppose both the fourth satellite and the third satellite have inter-satellite link connections to a certain satellite, then the fourth satellite and the third satellite can communicate through that satellite.

[0228] (3) The third server is deployed on the fourth satellite, which is the satellite that has deployed the application server or the local domain name system server and is closest to the third satellite. For example, suppose the terminal switches to the third satellite, but the third satellite does not deploy a local DNS server or one or more service-related EASs; then in order to provide the corresponding service to the terminal, the third satellite can obtain the satellite that has deployed a local DNS server or one or more service-related EASs among the satellites closest to the third satellite (that is, the fourth satellite), and provide the corresponding service to the terminal through the local DNS server or one or more service-related EASs on the fourth satellite. Optionally, the fourth satellite being closest to the third satellite can mean that the fourth satellite has deployed a local DNS server or one or more service-related EASs, and the fourth satellite and the third satellite meet one or more of the following conditions: fewest inter-satellite link hops, closest physical distance, lowest transmission latency, located in the same orbit, located in the same constellation, etc.; for example, the fourth satellite and the third satellite are closest in physical distance, or the fourth satellite and the third satellite are in the same orbit, etc., which are not limited in this application. The fourth satellite being closest to the third satellite can be defined as having the shortest straight-line distance between them (e.g., shorter than the distance between the fourth and third satellites in the same constellation); or having the fewest inter-satellite link hops between them (e.g., fewer than the number of inter-satellite link hops between the fourth and third satellites in the same constellation).

[0229] It is understood that the aforementioned third or fourth satellite may be a LEO satellite, MEO satellite, GEO satellite, or non-geostationary satellite orbit (NGSO) satellite, etc., and this application does not limit it.

[0230] S308, terminal accesses third server.

[0231] For example, if the third server is an EAS (Electronic Access System), when the UE determines to access a service (e.g., the user clicks on an app, and the app corresponds to an FQDN), the UE does not need to initiate a DNS query process. Instead, it directly accesses the third server, for example, by sending a service data packet to the EAS IP (e.g., 192.ppp) of that third server. As another example, if the third server is a local DNS server, when the UE determines to access a service, the UE sends a DNS query message (including the accessed FQDN) to that local DNS server IP. The local DNS server will carry the EAS IP (e.g., 192.mmm) deployed on the satellite currently accessed by the UE in the DNS response message. After receiving this DNS response message, the UE can access the third server, for example, by sending a service data packet to that EAS IP.

[0232] Optionally, following S306, the following steps are also included:

[0233] S309, when the location of the terminal changes, the SMF determines the second correspondence based on the changed location information of the terminal.

[0234] In this case, the changed location information of the terminal is different from the first location information. For example, when the terminal moves on the ground, its location changes, and the terminal's location information also changes. Therefore, the first correspondence will also change and become the second correspondence.

[0235] In one possible implementation, when the location of the terminal changes, the first network element may determine that the terminal's location has changed.

[0236] In one possible implementation, the second correspondence is similar to the first correspondence, but includes different specific information. For example, the second correspondence can also be represented in tabular form as shown in Tables 1 to 8, but the information filled in the table is different from the information filled in Tables 1 to 8. For example, similar to Table 1, the second correspondence can be shown in Table 10.

[0237] Table 10: The first type of second correspondence.

[0238] In this context, it is assumed that the SMF, based on the terminal's modified location and ephemeris information, determines that one or more satellites in the second correspondence are different from one or more satellites shown in Table 1 (e.g., one or more satellites in the second correspondence include satellite #3 or satellite #4, and satellite #3 or satellite #4 is different from satellite #1 or satellite #2). It is also assumed that satellite #3 can be associated with a local DNS server, with the IP address 192.eee, and satellite #4 can be associated with a local DNS server, with the IP address 192.fff. Therefore, the second correspondence includes the correspondence between one or more satellites and local domain name system servers, as shown in Table 10. It is understood that Table 10 is only one example, and more satellites corresponding to different local domain name system servers may be included; this application does not limit this.

[0239] Optionally, other forms of the second correspondence can be found in the descriptions in Tables 2 to 8. For example, similar to Table 2, the second correspondence is shown in Table 11.

[0240] Table 11: The second type of second correspondence.

[0241] As can be seen, compared to Table 2, one or more satellites in the second correspondence shown in Table 11 are different from one or more satellites in the first correspondence, and the addresses of the DNN and the local domain name system server may also be different. Table 11 is only an example and is not intended to limit the scope of this application.

[0242] S310, SMF sends the second correspondence to the terminal; correspondingly, the terminal receives the second correspondence.

[0243] In one possible implementation, when the second correspondence determined by the SMF includes different information, the second correspondence sent by the SMF to the terminal will also be different. For example, when the second correspondence determined by the SMF is as shown in Table 10, the second correspondence sent by the SMF to the terminal can be Table 10.

[0244] Optionally, the SMF sends a second mapping relationship to the terminal. Specifically, the SMF may send the second mapping relationship to the terminal through the AMF and / or RAN.

[0245] In one possible implementation, the second mapping relationship is carried in a first message, which can be any of the following: a session establishment acceptance message or a session modification instruction. For example, when the SMF sends the second mapping relationship to the terminal, it can be that the SMF sends a first message to the terminal, which can be a session establishment acceptance message or a session modification instruction, and the first message includes the second mapping relationship.

[0246] It is understood that the execution of S307 and S308 is unrelated to the execution of S309 and S310. For example, only S307 and S308 can be executed, or only S309 and S310 can be executed, or S307 and S308 can be executed simultaneously with S309 and S310, or S307 and S308 can be executed first and then S309 and S310. This application does not impose any restrictions.

[0247] In Example 1, during the session establishment / modification process, the SMF can determine the first correspondence based on one or more of the terminal's first location information, the terminal's first service information, the first satellite, and ephemeris information, and send the first correspondence to the terminal. Correspondingly, the terminal determines the EAS IP / local DNS server IP to use when accessing services based on the received first correspondence, without the terminal needing to re-initiate the EAS selection process, thereby reducing satellite-to-ground interaction and lowering communication overhead.

[0248] Example 2: In the UE registration / UE configuration update process, the first network element sends the first correspondence to the UE; the UE accesses the network based on the first correspondence and optimizes the UE reselection EAS process to reduce satellite-to-ground interaction. For example, Figure 5 is a flowchart of Example 2 provided in this application. This process can be implemented through interaction between the UE, AMF or PCF (in this embodiment, the AMF or PCF can implement the functions of the first network element in the embodiments of Figures 2 and 3), and the first server (such as EAS or local DNS server), including the following steps:

[0249] S401, the terminal sends a registration request message to the AMF; correspondingly, the AMF receives the registration request message.

[0250] For example, when a terminal accesses the first satellite and requests registration, it can send a registration request message (such as a Registration request) to the AMF; specifically, the terminal can send the registration request message to the AMF through the RAN (which can be deployed on the first satellite).

[0251] In an implementation where the first network element is AMF, the following steps are included:

[0252] S402a, AMF determines the first correspondence based on one or more of the terminal's first location information, first satellite, and ephemeris information.

[0253] It should be noted that the main difference between Example 2 and Example 1 is that the UE has not yet established a session, and it is temporarily impossible to determine which DNN the UE will access (for example, the UE may establish multiple sessions at the same time); therefore, the main difference between the first correspondence in Example 2 and the first correspondence in Example 1 is that the first correspondence in Example 2 also includes the DNN.

[0254] Specifically, S402a includes, but is not limited to, the following specific implementation methods:

[0255] Implementation Method 1: Based on the first location information, the first satellite, and the first service information, the AMF determines the first correspondence, which includes: the correspondence between one or more satellites, one or more data network names and the local domain name system server, or the correspondence between one or more satellites, one or more data network names, one or more service domain names and the application servers corresponding to one or more service domain names.

[0256] For example, suppose one or more satellites include satellite #1 and satellite #2, and suppose satellite #1 can be associated with one or more local DNS servers, whose IP addresses are represented as 192.mmm, 192.nnn, etc. It's important to note that one satellite can be associated with multiple local DNS servers because these servers have different characteristics, such as corresponding to different DNNs; and suppose these different DNNs are represented as DNN#1, DNN#2, etc. Suppose satellite #2 can be associated with one or more local DNS servers, whose IP addresses are represented as 192.aaa, 192.bbb, etc. The first correspondence is shown in Table 2, and will not be elaborated further here.

[0257] For example, suppose one or more satellites include satellite #1 and satellite #2, and suppose satellite #1 can be associated with one or more local DNS servers, whose IP addresses are represented as 192.mmm, 192.nnn, etc. It's important to note that one satellite can be associated with multiple local DNS servers because these servers have different characteristics, such as corresponding to different DNNs and FQDNs. Suppose satellite #2 can be associated with one or more local DNS servers, whose IP addresses are represented as 192.aaa, 192.bbb, etc. The first correspondence is shown in Table 4, and will not be elaborated further here.

[0258] Implementation Method 2: Based on the first location information, the first satellite, ephemeris information, and the first service information, the AMF determines the first correspondence, including: the correspondence between time, one or more data network names and the local domain name system server, or the correspondence between time, one or more data network names, one or more service domain names and the application server corresponding to one or more service domain names.

[0259] For example, suppose the time includes time #1 (e.g., 9:00~9:10) and time #2 (e.g., 9:10~9:20), and suppose time #1 can be associated with one or more local DNS servers, assuming the IP addresses of these local DNS servers are represented as 192.mmm, 192.nnn, etc. It's important to note that one time can be associated with multiple local DNS servers because these servers have different characteristics, such as corresponding to different DNNs. Alternatively, suppose time #2 can be associated with one or more local DNS servers, assuming the IP addresses of these local DNS servers are represented as 192.aaa, 192.bbb, etc. The first correspondence is shown in Table 6, and will not be elaborated further here.

[0260] For example, suppose the time includes time #1 (e.g., 9:00~9:10) and time #2 (e.g., 9:10~9:20), and suppose time #1 can be associated with one or more EAS, and suppose the IP of these one or more EAS is represented as 192.mmm, 192.nnn; and suppose time #1 can be associated with one or more EAS, and suppose the IP of these one or more EAS is represented as 192.aaa, 192.bbb. Suppose the first service information includes one or more DNNs, and these one or more DNNs are represented as DNN#1, DNN#2, etc., then the first correspondence is shown in Table 8, which will not be elaborated here.

[0261] Optionally, the first correspondence determined by AMF in S402a may include different tables from those in Embodiment 1 and Embodiment 2, for example, corresponding to different FQDNs. This application does not limit the specific form of the first correspondence; for example, other table forms may be used to represent the first correspondence, as long as they can reflect the above-mentioned first correspondence.

[0262] S403a, AMF sends the first correspondence to the terminal; correspondingly, the terminal receives the first correspondence.

[0263] In one possible implementation, when the first correspondence determined by the AMF includes different information, the first correspondence sent by the AMF to the terminal will also be different. For example, when the first correspondence determined by the AMF is as shown in Table 6, the first correspondence sent by the AMF to the terminal can be Table 6. As another example, when the first correspondence determined by the AMF is as shown in Table 8, the first correspondence sent by the AMF to the terminal can be Table 8.

[0264] Optionally, the AMF sends the first correspondence to the terminal, specifically through the RAN.

[0265] In one possible implementation, the first correspondence is carried in a first message, which is a registration acceptance message. For example, the AMF sends the first correspondence to the terminal by sending a first message, which is either a registration accept message or a UE configuration update command, and this first message includes the first correspondence.

[0266] In an implementation where the first network element is a PCF, the following steps are included:

[0267] S402b, PCF determines the first correspondence based on one or more of the terminal's first location information, first satellite, and ephemeris information.

[0268] Optionally, prior to S402b, the AMF can send a policy association message to the PCF. This policy association information is used to instruct the UE to access the first satellite and to interact with the PCF through the AMF. This policy association message can be an access management (AM) policy association message, a mobility management (MM) policy association message, or a session management (SM) policy association message; this application does not limit the specific type of message.

[0269] Specifically, the specific implementation of S402b is similar to that of S402a, including, but not limited to, implementations one and two described in S402a. Therefore, the first correspondence determined by the PCF is also similar, as shown in Tables 1 to 8, and will not be repeated here.

[0270] S403b, PCF sends the first correspondence to the terminal; correspondingly, the terminal receives the first correspondence.

[0271] In one possible implementation, when the first correspondence determined by the PCF includes different information, the first correspondence sent by the PCF to the terminal will also be different. For example, when the first correspondence determined by the PCF is as shown in Table 2, the first correspondence sent by the PCF to the terminal can be Table 2. As another example, when the first correspondence determined by the PCF is as shown in Table 4, the first correspondence sent by the PCF to the terminal can be Table 4.

[0272] Optionally, the PCF sends the first correspondence to the terminal. Specifically, the PCF can send the first correspondence to the terminal through the AMF and RAN.

[0273] In one possible implementation, the first correspondence is carried in a first message, which is a routing policy. For example, the PCF sends the first correspondence to the terminal by sending a first message, which is a UE route selection policy (URSP), and the first message includes the first correspondence.

[0274] It is understandable that S402a and S403a are parallel schemes with S402b and S403b. For example, if S402a and S403a are executed, then S402b and S403b are not executed, or if S402b and S403b are executed, then S402a and S403a are not executed. These two parallel schemes can achieve the same effect for the terminal, that is, the terminal can obtain the first correspondence.

[0275] S404, When a terminal initiates a first service, the terminal determines the second server based on the first correspondence.

[0276] S405, the terminal accesses the second server.

[0277] The specific implementations of S404 and S405 can be referred to the corresponding descriptions in S305 and S306, respectively. For example, the terminal determines the second server based on the first correspondence relationship. Specifically, the terminal determines the second server based on the first correspondence relationship, the first service, the terminal's first location information and ephemeris information, and the definition of the second server, etc. Specific examples will not be repeated here.

[0278] Optionally, following S405, the following steps are also included:

[0279] S406, when the terminal switches to the third satellite, the third server is determined based on the first correspondence.

[0280] S407, terminal accesses third server.

[0281] The specific implementations of S406 and S407 can be referred to the corresponding descriptions in S307 and S308, respectively. For example, the terminal determines the third server based on the first correspondence relationship. Specifically, the terminal determines the third server based on the first correspondence relationship, the first service, the terminal's first location information and ephemeris information, and the definition of the third server, etc. Specific examples will not be repeated here.

[0282] Optionally, following S405, the following steps are also included:

[0283] S408a, when the location of the terminal changes, the AMF determines the second correspondence based on the changed location information of the terminal.

[0284] S409a, AMF sends the second correspondence to the terminal.

[0285] The specific implementations of S408a and S409a can be referred to the corresponding descriptions in S309 and S310, respectively. For example, when the terminal moves on the ground, the terminal's position changes, and the terminal's position information also changes. The first correspondence relationship will also change and become the second correspondence relationship. The second correspondence relationship is similar to the first correspondence relationship, but the specific information included is different. Specific examples of the second correspondence relationship will not be repeated here.

[0286] Optionally, following S405, the following steps are also included:

[0287] S408b, when the location of the terminal changes, the PCF determines the second correspondence based on the changed location information of the terminal.

[0288] S409b, PCF sends the second correspondence to the terminal.

[0289] The specific implementations of S408b and S409b can be referred to the corresponding descriptions in S309 and S310, respectively. For example, when the terminal moves on the ground, the terminal's position changes, and the terminal's position information also changes. The first correspondence relationship will also change and become the second correspondence relationship. The second correspondence relationship is similar to the first correspondence relationship, but the specific information included is different. Specific examples of the second correspondence relationship will not be elaborated here.

[0290] It is understandable that S408a and S409a are parallel schemes to S408b and S409b. For example, if S408a and S409a are executed, then S408b and S409b are not executed, or vice versa. These two parallel schemes achieve the same effect for the terminal, namely, the terminal can obtain the second correspondence. It is also understandable that S408a and S409a are related to the schemes of S402a and S403a, both being operations executed by the AMF; S408b and S409b are related to the schemes of S402b and S403b, both being operations executed by the PCF.

[0291] It is understood that the execution of S406 and S407 is unrelated to the execution of S408a and S409a. For example, only S406 and S407 can be executed, or only S408a and S409a can be executed, or S406 and S407 can be executed simultaneously with S408a and S409a, or S406 and S407 can be executed first and then S408a and S409a; this application does not impose any limitations. Similarly, the execution of S406 and S407 is unrelated to the execution of S408b and S409b. For example, only S406 and S407 can be executed, or only S408b and S409b can be executed, or S406 and S407 can be executed simultaneously with S408b and S409b, or S406 and S407 can be executed first and then S408b and S409b; this application does not impose any limitations.

[0292] In Example 2, during the UE registration / UE configuration update process, the AMF / PCF can determine the first correspondence based on one or more of the terminal's first location information, the terminal's first service information, the first satellite, and ephemeris information, and send the first correspondence to the terminal. Correspondingly, the terminal determines the EAS IP / local DNS server IP to use when accessing services based on the received first correspondence, without the terminal needing to re-initiate the EAS selection process, thereby reducing satellite-to-ground interaction and lowering communication overhead.

[0293] Example 3: In the UE DNS query process, the first network element sends the first correspondence to the UE; the UE accesses the network based on the first correspondence and optimizes the UE reselection of EAS process to reduce satellite-to-ground interaction. For example, Figure 6 is a flowchart of Example 3 provided in this application. This process can be implemented through interaction between the UE, EASDF, SMF (in this embodiment, the SMF can implement the functions of the first network element in the embodiments of Figures 2 and 3), and a second server (such as EAS or a local DNS server), including the following steps:

[0294] S501, the terminal sends a DNS request to EASDF; correspondingly, EASDF receives the DNS request.

[0295] For example, after the session is established, the UE sends a DNS query to the EASDF, which includes the FQDN of the first service requested by the terminal.

[0296] S502, EASDF sends a DNS request to SMF; correspondingly, EASDF receives the DNS request.

[0297] For example, if the EASDF determines that the FQDN included in a DNS query from an endpoint is within the scope of a DNS handling rule, it can report the DNS query to the SMF.

[0298] S503, SMF determines the first correspondence based on one or more of the terminal's first location information, the terminal's first service information, the first satellite, and ephemeris information.

[0299] Unlike Example 1, in Example 3, the first service information of the terminal is the first service domain name (i.e., the FQDN of the first service requested by the terminal). In this case, the SMF can determine the first correspondence based on one or more of the first location information, the first service domain name, the first satellite, and the ephemeris information.

[0300] Specifically, S503 includes, but is not limited to, the following specific implementation methods:

[0301] Implementation Method 1: Based on the first location information, the first satellite, and the first service information, the SMF determines that the first correspondence includes one or more of the following: a correspondence between one or more satellites and a local domain name system server; a correspondence between one or more satellites, one or more service domain names, and application servers corresponding to one or more service domain names; or a correspondence between one or more satellites, one or more data network names, one or more service domain names, and application servers corresponding to one or more service domain names. Wherein, the one or more service domain names include the first service domain name, which is the service domain name corresponding to the service requested by the terminal.

[0302] For example, suppose the first satellite is represented as satellite #1, and satellite #1 can be associated with a local DNS server, and suppose the local DNS server IP is represented as 192.aaa. Optionally, one or more satellites may also include other satellites (such as satellite #2, and satellite #2 can be associated with a local DNS server, and suppose the local DNS server IP is represented as 192.bbb). The first correspondence is shown in Table 1, which will not be elaborated here.

[0303] For example, suppose the first business domain name is represented as www.xxx.com, and one or more satellites include satellite #1 and satellite #2. Suppose that satellite #1 can be associated with the first business domain name, and suppose that the EAS IP corresponding to the first business domain name associated with satellite #1 is represented as 192.mmm; suppose that satellite #2 can be associated with the first business domain name, and suppose that the EAS IP corresponding to the first business domain name associated with satellite #2 is represented as 192.nnn. Then the first correspondence is shown in Table 12.

[0304] Table 12: Correspondence between one or more satellites, the first business domain name, and the application server.

[0305] Understandably, Table 12 is only an example, with fewer entries than Table 3, and only includes the correspondence related to the first business domain name, which helps to simplify the first correspondence.

[0306] Implementation Method 2: Based on the first location information, the first satellite, ephemeris information, and the first service information, SMF determines the first correspondence relationship, including: the correspondence relationship between time and the local domain name system server, or the correspondence relationship between time, the first service domain name, and the application server corresponding to the first service domain name.

[0307] For example, suppose the time includes time #1 (e.g., 9:00~9:10) and time #2 (e.g., 9:10~9:20), and time #1 can be associated with a local DNS server, assuming the local DNS server IP is represented as 192.aaa; time #2 can be associated with a local DNS server, assuming the local DNS server IP is represented as 192.bbb; then the first correspondence is shown in Table 5, which will not be elaborated here.

[0308] For example, suppose the first business domain name is represented as www.xxx.com, and the time includes time #1 (e.g., 9:00~9:10) and time #2 (e.g., 9:10~9:20), etc., and time #1 can be associated with a local DNS server, assuming that the local DNS server IP is represented as 192.aaa; time #2 can be associated with a local DNS server, assuming that the local DNS server IP is represented as 192.bbb; then the first correspondence is shown in Table 13.

[0309] Table 13: Correspondence between time, first business domain name and application server corresponding to the first business domain name.

[0310] Understandably, Table 13 is only an example, with fewer entries than Table 7, and only includes the correspondence related to the first business domain name, which helps to simplify the first correspondence.

[0311] S504, SMF sends the first correspondence to the terminal; correspondingly, the terminal receives the first correspondence.

[0312] In one possible implementation, when the first correspondence determined by the SMF includes different information, the first correspondence sent by the SMF to the terminal will also be different. For example, when the first correspondence determined by the SMF is as shown in Table 12, the first correspondence sent by the SMF to the terminal can be Table 12. As another example, when the first correspondence determined by the SMF is as shown in Table 13, the first correspondence sent by the SMF to the terminal can be Table 13.

[0313] Optionally, the SMF sends the first correspondence to the terminal. Specifically, the SMF may send the first correspondence to the terminal through the AMF and / or RAN.

[0314] In one possible implementation, the first correspondence is carried in a first message, which can be any of the following: a session modification command. For example, the SMF sending the first correspondence to the terminal can be done by the SMF sending a first message to the terminal, which can be a session modification command (PDU) including the first correspondence.

[0315] S505: When a terminal initiates a first service, the terminal determines the second server based on the first correspondence.

[0316] The specific implementation of S505 can be referred to the corresponding description in S305. The difference lies in the specific content of the first correspondence, which will not be repeated here.

[0317] S506, the terminal accesses the second server.

[0318] The specific implementation of S505 can be referred to the corresponding description in S305, and will not be repeated here.

[0319] Optionally, following S506, the following steps are also included:

[0320] S507, when the terminal switches to the third satellite, the terminal determines the third server based on the first correspondence.

[0321] S508, terminal accesses third server.

[0322] The specific implementations of S507 and S508 can be found in the corresponding descriptions in S307 and S308, and will not be repeated here.

[0323] Optionally, following S506, the following steps are also included:

[0324] S509, when the location of the terminal changes, the SMF determines the second correspondence based on the changed location information of the terminal.

[0325] S510, SMF sends the second mapping relationship to the terminal; correspondingly, the terminal receives the second mapping relationship.

[0326] The specific implementation methods of S509 and S510 can be referred to the corresponding descriptions in S309 and S310, and will not be repeated here.

[0327] It is understood that the execution of S507 and S508 is unrelated to the execution of S509 and S510. For example, only S507 and S508 can be executed, or only S509 and S510 can be executed, or S507 and S508 can be executed simultaneously with S509 and S510, or S507 and S508 can be executed first and then S509 and S510. This application does not impose any restrictions.

[0328] Optionally, following S506, the following steps are also included:

[0329] S511, when the location of the terminal changes, the SMF sends a fifth message to the terminal, which instructs the terminal to delete the first correspondence.

[0330] For example, when the terminal's location changes, the SMF can instruct the terminal to delete the stored first mapping relationship (the first mapping relationship is only related to the first service domain name). Optionally, when the terminal needs to access a service (such as re-accessing the first service or accessing a new second service), the terminal needs to re-initiate a DNS query and re-obtain the first mapping relationship (such as re-executing S501 to S504).

[0331] In Example 3, during the UE DNS query process, the SMF can determine the first correspondence based on one or more of the terminal's first location information, first service domain name, first satellite, and ephemeris information, and send the first correspondence to the terminal. Correspondingly, the terminal determines the EAS IP / local DNS server IP used when accessing services based on the received first correspondence, without the terminal needing to re-initiate the EAS selection process, thereby reducing satellite-to-ground interaction and lowering communication overhead.

[0332] For example, Figure 7 is a flowchart illustrating the third communication method provided in this application. This method is implemented through interaction between a first satellite and a terminal. For example, the first satellite may be a satellite, a functional entity performing related functions on a satellite, or an access network device deployed on a satellite; the terminal may be a terminal device or its components, or a chip or circuit applied to the terminal, etc.; the method includes the following steps:

[0333] S601, the first satellite obtains the third correspondence.

[0334] In one possible implementation, the first satellite acquires the third correspondence, which may include the following situations:

[0335] (1) The first satellite stores the third correspondence locally; when needed, the first satellite can read the third correspondence stored locally to obtain the third correspondence.

[0336] (2) The first satellite is configured with a third correspondence; for example, the core network element (such as AMF) can determine the third correspondence and configure the third correspondence to the first satellite, so that the first satellite can obtain the third correspondence.

[0337] (3) The first satellite determines the third correspondence based on local logic; for example, assuming that a local domain name system server is deployed on the first satellite, the first satellite can determine that the third correspondence includes the local domain name system server deployed on the first satellite.

[0338] (4) The first satellite obtains the third correspondence from other entities / network elements; for example, the AMF can send the third correspondence to the first satellite, so that the first satellite can obtain the third correspondence.

[0339] In one possible implementation, the third mapping is the address of the local DNS server. For example, assuming a local DNS server is deployed on the first satellite, the third mapping is the address of the local DNS server deployed on the first satellite (local DNS server IP address).

[0340] In one possible implementation, the third correspondence includes the correspondence between the local domain name system server and the data network name. For example, assuming that multiple DNNs are deployed on the first satellite, and different DNNs correspond to different local DNS server IPs, the third correspondence can be described with reference to Table 3. That is, the third correspondence includes the correspondence between one or more satellites, one or more data network names, and the local domain name system server.

[0341] In one possible implementation, the third correspondence further includes at least one of the following:

[0342] (1) The correspondence between one or more satellites, one or more data network names, and local domain name system servers. For example, suppose one or more satellites include satellite #1 and satellite #2, and suppose satellite #1 can be associated with one or more local DNS servers, and suppose the IP of these one or more local DNS servers is represented as 192.mmm, 192.nnn, etc. It should be noted that one satellite is associated with multiple local domain name system servers because multiple local domain name system servers have different characteristics, such as corresponding to different DNNs; and suppose the different DNNs are represented as DNN#1, DNN#2, etc. Suppose satellite #2 can also be associated with one or more local DNS servers, and suppose the IP of these one or more local DNS servers is represented as 192.aaa, 192.bbb, etc., then the third correspondence is shown in Table 2, which will not be elaborated here.

[0343] (2) The correspondence between time, one or more data network names, and local domain name system servers. For example, suppose the time includes time #1 (e.g., 9:00~9:10) and time #2 (e.g., 9:10~9:20), and suppose time #1 can be associated with one or more local DNS servers, and suppose the IP of these one or more local DNS servers is represented as 192.mmm, 192.nnn, etc. It should be noted that one time can be associated with multiple local domain name system servers because multiple local domain name system servers have different characteristics, such as corresponding to different DNNs. Optionally, suppose time #2 can be associated with one or more local DNS servers, and suppose the IP of these one or more local DNS servers is represented as 192.aaa, 192.bbb, etc., then the first correspondence is shown in Table 6, which will not be elaborated here.

[0344] In one possible implementation, the local domain name system server is associated with the first satellite, and this association may include, but is not limited to, the following:

[0345] (1) The local domain name system server is deployed on the first satellite. For example, if a terminal is connected to the first satellite, the local DNS server on the first satellite can provide the corresponding service to the terminal.

[0346] (2) The local DNS server is deployed on the second satellite, which is a satellite that has deployed a local DNS server and is connected to the first satellite. For example, suppose a terminal connects to the first satellite, but the first satellite does not have a local DNS server deployed; then, in order to provide the corresponding service to the terminal, the first satellite can find a satellite connected to the first satellite that has a local DNS server deployed (i.e., the second satellite), and provide the corresponding service to the terminal through the local DNS server on the second satellite. Optionally, the relevant description of the connection between the second satellite and the first satellite can be referred to the corresponding description in S101, and will not be repeated here.

[0347] (3) The local DNS server is deployed on the second satellite, which is the satellite with the local DNS server deployed and the closest to the first satellite. For example, suppose the terminal connects to the first satellite, but the first satellite does not have a local DNS server deployed; then, in order to provide the corresponding service to the terminal, the first satellite can obtain the local DNS server deployed on the satellite closest to the first satellite (i.e., the second satellite), and provide the corresponding service to the terminal through the second satellite. Optionally, the relevant description of the second satellite being closest to the first satellite can be referred to the corresponding description in S101, and will not be repeated here.

[0348] S602, the first satellite sends the third correspondence; correspondingly, the terminal receives the third correspondence.

[0349] In one possible implementation, the first satellite transmits the third correspondence, which can be done by broadcasting the third correspondence. For example, the first satellite can broadcast the third correspondence via MIB or SIB messages. Correspondingly, after receiving the broadcast message, the terminal can store the third correspondence.

[0350] In one possible implementation, the first satellite sends the third correspondence, which can be done by sending the third correspondence to the terminal via an RRC message. For example, the first satellite can send an RRC message to the terminal that includes the third correspondence.

[0351] It should be noted that in this embodiment, the first satellite may refer to a dedicated function network element deployed on the first satellite to perform the relevant functions described in S601 and S602, or the first satellite may refer to an AMF, SMF or part of the functions of the AMF, SMF deployed on the first satellite to realize the relevant functions described in S601 and S602, or the first satellite may refer to a RAN deployed on the first satellite to realize the relevant functions described in S601 and S602. This application does not limit it.

[0352] The following will detail the specific implementation of the embodiment shown in Figure 7 through several concrete examples, and explain how it is applied to optimize the UE reselection of EAS process.

[0353] Example 4: The first satellite broadcasts a third correspondence to the UE; the UE accesses the network based on the third correspondence and optimizes the UE reselection EAS process to reduce satellite-to-ground interaction. For example, Figure 8 is a flowchart of Example 4 provided in this application. This process can be implemented through interaction between the UE, the first satellite, and the local domain name system server, including the following steps:

[0354] S701, the first satellite broadcast and the third corresponding relationship.

[0355] For example, the first satellite can broadcast this third correspondence via MIB or SIB broadcast messages. A detailed description of the third correspondence can be found in the embodiment shown in Figure 7, and will not be repeated here.

[0356] S702, the terminal stores the third correspondence in the broadcast message.

[0357] For example, after receiving a MIB or SIB broadcast message, the terminal can store a third-party mapping in the broadcast message (e.g., storing the local DNS server IP).

[0358] S703, the terminal sends a third message to the first satellite; correspondingly, the first satellite receives the third message.

[0359] In one possible implementation, the third message is an RRC connection establishment message. For example, if a RAN is deployed on a first satellite and a terminal requests access to the RAN deployed on the first satellite, the terminal sends an RRC connection establishment message to the first satellite to establish an RRC connection.

[0360] In one possible implementation, the third message is an RRC connection re-establishment message. For example, if a RAN is deployed on the first satellite and the terminal requests to re-establish a connection with the RAN deployed on the first satellite, the terminal sends an RRC connection re-establishment message to the first satellite, thereby re-establishing the RRC connection.

[0361] S704: When a terminal performs a service, it sends a DNS query request to the address of the local Domain Name System server.

[0362] For example, after a terminal connects to the first satellite (such as the RAN deployed on the first satellite), it can send a DNS query to the corresponding local DNS server IP.

[0363] Optionally, after S704, a follow-up process of DNS query can be executed. For details, please refer to the description of the follow-up process of DNS query in the previous embodiment. For example, the local DNS server can return the corresponding EAS IP, so that the terminal can send data packets to the EAS IP, etc., which will not be elaborated here.

[0364] In Example 4, the first satellite determines the third correspondence and broadcasts it. Correspondingly, when the terminal performs a service, it can determine the local DNS server IP used to access the service based on the received third correspondence, and then obtain the EAS IP, thereby reducing satellite-to-ground interaction and reducing communication overhead.

[0365] Example 5: The first satellite sends a third mapping relationship to the UE via an RRC configuration message; the UE accesses the network based on the third mapping relationship and optimizes the UE reselection EAS process to reduce satellite-to-ground interaction. For example, Figure 9 is a flowchart of Example 5 provided in this application. This process can be implemented through interaction between the UE, the first satellite, and the local domain name system server, including the following steps:

[0366] S801, the terminal sends a second message to the first satellite; correspondingly, the first satellite receives the second message.

[0367] The second message is used to request the address of the local domain name system server deployed on the first satellite. For example, the second message could be an RRC reconfiguration complete message, which requests the address of the local domain name system server deployed on the first satellite, thereby enabling the terminal to perform the first service.

[0368] Optionally, prior to S801, the following operation is also included: The fifth satellite sends an RRC reconfiguration message to the terminal, which instructs the terminal to switch to the first satellite. Here, the fifth satellite is the satellite the terminal was connected to before connecting to the first satellite; for example, the terminal was previously connected to the fifth satellite and was receiving services from it; however, due to the high-speed movement of the satellite, the fifth satellite can no longer provide services to the terminal, so it can instruct the terminal to switch to another satellite (such as the first satellite) via the RRC reconfiguration message. Therefore, the terminal can send an RRC reconfiguration complete message to the first satellite to request access to the first satellite and obtain the address of the local domain name system server deployed on the first satellite.

[0369] S802, the first satellite sends an RRC message to the terminal; correspondingly, the terminal receives the RRC message.

[0370] The RRC message includes a third mapping. For example, when the first satellite sends an RRC message to the terminal, this message includes the local DNS server IP or the mapping between the local DNS server IP and the DNN. A detailed description of the third mapping can be found in the embodiment shown in Figure 7, and will not be repeated here.

[0371] S803, the terminal stores the third correspondence in the RRC message.

[0372] For example, after receiving an RRC message, the terminal can use the third mapping in the RRC message (e.g., storing the local DNS server IP).

[0373] S804, the terminal sends a DNS query request to the address of the local Domain Name System server.

[0374] For example, after a terminal connects to the first satellite (such as the RAN deployed on the first satellite), it can send a DNS query to the corresponding local DNS server IP.

[0375] Optionally, after S804, a follow-up process for the DNS query can be executed. For details, please refer to the description of the follow-up process for the DNS query in the previous embodiment. For example, the local DNS server can return the corresponding EAS IP, so that the terminal can send data packets to the EAS IP, etc., which will not be elaborated here.

[0376] In Example 5, the first satellite determines the third correspondence and sends the third correspondence to the terminal via an RRC message. Correspondingly, when the terminal performs services, it can determine the local DNS server IP used to access the services based on the received third correspondence, and then obtain the EAS IP, thereby reducing satellite-to-ground interaction and reducing communication overhead.

[0377] It is understood that, in order to achieve the functions described in the above embodiments of the device, the base station and the terminal include hardware structures and / or software modules corresponding to perform each function. Those skilled in the art should readily recognize that, based on the units and method steps of the various examples described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0378] Figures 10 and 11 are schematic diagrams of the communication devices provided in this application. These communication devices can be used to implement the functions of the first network element, terminal, or first satellite in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments.

[0379] As shown in Figure 10, the communication device 1000 includes a processing unit 1010 and a transceiver unit 1020. The communication device 1000 is used to implement the functions of the first device, the second device, or the first network element in the method embodiments shown in Figures 2 to 9. Optionally, the transceiver unit 1020 includes a sending unit and a receiving unit, and the transceiver unit 1020 can also be referred to as a communication unit.

[0380] When the communication device 1000 is used to implement the function of the first network element in the method embodiments shown in Figures 2 to 6: the processing unit 1010 is used to determine the first server based on ephemeris information and the first location information of the terminal. The first server includes a local domain name system server or one or more application servers corresponding to services. The transceiver unit 1020 is used to send information about the first server to the terminal; the first server is associated with the first satellite accessed by the terminal.

[0381] In one possible implementation, the ephemeris information includes at least the ephemeris information of the first satellite, or the ephemeris information of more satellites, such as the ephemeris information of all satellites in the constellation / orbit to which the first satellite is located.

[0382] In one possible implementation, before the processing unit 1010 determines the first server based on the ephemeris information and the terminal's first location information, the first network element determines that the terminal accesses the network via a non-terrestrial network.

[0383] In one possible implementation, the transceiver unit 1020 is used to receive first indication information, which is used to instruct the terminal to access the first satellite.

[0384] In one possible implementation, the transceiver unit 1020 is used to send a first correspondence to the terminal; the first correspondence includes one or more of the following:

[0385] The mapping relationship between one or more satellites and local domain name system servers;

[0386] The correspondence between one or more satellites, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0387] The correspondence between time and the local domain name system server;

[0388] The correspondence between time, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0389] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0390] In one possible implementation, the transceiver unit 1020 is used to send a first correspondence to the terminal, the first correspondence including one or more of the following:

[0391] The mapping between one or more satellites, one or more data network names, and local domain name system servers;

[0392] The correspondence between one or more satellites, one or more data network names, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0393] The mapping between time, one or more data network names, and the local domain name system server;

[0394] The correspondence between time, one or more data network names, one or more business domain names and the application servers corresponding to the one or more business domain names;

[0395] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0396] In one possible implementation, the transceiver unit 1020 is used to send a first correspondence to the terminal, the first correspondence including one or more of the following:

[0397] The mapping relationship between one or more satellites and local domain name system servers;

[0398] The mapping relationship between one or more satellites, one or more business domain names, and the application servers corresponding to one or more business domain names;

[0399] The correspondence between time and the local domain name system server;

[0400] The mapping relationship between time, one or more business domain names, and the application servers corresponding to one or more business domain names;

[0401] In one possible implementation, one or more satellites include a first satellite; time includes the current time; one or more service domains include a first service domain, which is the service domain corresponding to the service requested by the terminal.

[0402] In one possible implementation, one or more times include a first time, which is the time when the first satellite provides services to the terminal.

[0403] In one possible implementation, the processing unit 1010 is used to determine a first correspondence based on one or more of the following: first location information, first service information of the terminal, first satellite, and ephemeris information; the first service information includes at least one of the following: data network name, network slice selection auxiliary information, and service domain name.

[0404] In one possible implementation, the information of the first server or the first correspondence is carried in the first message, which is any one of the following: session establishment acceptance message, session modification instruction, registration acceptance message, or UE configuration update instruction.

[0405] In one possible implementation, when the location of the terminal changes, the transceiver unit 1020 sends a second correspondence; the location information of the terminal after the change is different from the first location information.

[0406] In one possible implementation, when the location of the terminal changes, the first network element may determine that the terminal's location has changed.

[0407] As can be seen, when the communication device 1000 is used to implement the function of the first network element in the method embodiments shown in Figures 2 to 6, the communication device 1000 can determine the first server that provides the corresponding service to the terminal. The UE does not need to re-initiate the DNS process. Instead, the first server can be determined based on the ephemeris information and the terminal's first location information. This optimizes the process of the UE reselecting the EAS, thereby reducing satellite-to-ground interaction and reducing communication overhead.

[0408] When the communication device 1000 is used to implement the terminal functions in the method embodiments shown in Figures 2 to 6: when the processing unit 1010 initiates the first service, it determines the second server based on the first correspondence relationship. The second server includes an application server to be accessed or a local domain name system server; the application server to be accessed or the local domain name system server is deployed on a satellite. The transceiver unit 1020 is used to access the second server.

[0409] In one possible implementation, the terminal accesses a first satellite. The first correspondence includes one or more of the following: a correspondence between the first satellite and a local domain name system server, a correspondence between the first satellite and an application server corresponding to the first service, a correspondence between a first time and the local domain name system server, and a correspondence between a first time and an application server corresponding to the first service. Here, the first time refers to the time during which the first satellite provides services to the terminal.

[0410] In one possible implementation, the processing unit 1010 is configured to determine a second server based on a first correspondence and at least one of the following: a first service, service information corresponding to the first service, a first satellite accessed by the terminal, and the current time; the second server is a server deployed on either the first or second satellite. The second satellite is either a satellite with an application server or a local domain name system server deployed thereon and connected to the first satellite; or the second satellite is either a satellite with an application server or a local domain name system server deployed thereon and the closest satellite to the first satellite.

[0411] In one possible implementation, the connection between the second satellite and the first satellite could mean that there is an inter-satellite link between them; or, the second satellite and the first satellite could communicate via one-hop or multi-hop inter-satellite links. For example, assuming that both the second satellite and the first satellite are connected to a certain satellite via an inter-satellite link, then the second satellite and the first satellite can communicate through that satellite.

[0412] In one possible implementation, the second satellite being closest to the first satellite can be defined as having the shortest straight-line distance between the second and first satellites (e.g., shorter than the distance between the second and first satellites in the same constellation); or having the fewest inter-satellite link hops between the second and first satellites (e.g., fewer than the number of inter-satellite link hops between the second and first satellites in the same constellation).

[0413] In one possible implementation, the first correspondence includes one or more of the following:

[0414] The mapping relationship between one or more satellites and local domain name system servers;

[0415] The correspondence between one or more satellites, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0416] The correspondence between time and the local domain name system server;

[0417] The correspondence between time, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0418] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0419] In one possible implementation, the first correspondence includes one or more of the following:

[0420] The mapping between one or more satellites, one or more data network names, and local domain name system servers;

[0421] The correspondence between one or more satellites, one or more data network names, one or more business domain names, and the application servers corresponding to the one or more business domain names;

[0422] The mapping between time, one or more data network names, and the local domain name system server;

[0423] The correspondence between time, one or more data network names, one or more business domain names and the application servers corresponding to the one or more business domain names;

[0424] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0425] In one possible implementation, the first correspondence includes one or more of the following:

[0426] The mapping relationship between one or more satellites and local domain name system servers;

[0427] The mapping relationship between one or more satellites, one or more business domain names, and the application servers corresponding to one or more business domain names;

[0428] The correspondence between time and the local domain name system server;

[0429] The mapping relationship between time, one or more business domain names, and the application servers corresponding to one or more business domain names;

[0430] In one possible implementation, one or more satellites include a first satellite; time includes the current time; one or more service domains include a first service domain, which is the service domain corresponding to the service requested by the terminal.

[0431] In one possible implementation, the transceiver unit 1020 is used to receive a first message, which includes a first correspondence. The first message can be any of the following: a session establishment acceptance message, a session modification instruction, a registration acceptance message, or a UE configuration update instruction.

[0432] In one possible implementation, when the location of the terminal changes, the transceiver unit 1020 is used to receive the second correspondence; the location information of the terminal after the change is different from the first location information.

[0433] In one possible implementation, when the location of the terminal changes, the first network element may determine that the terminal's location has changed.

[0434] As can be seen, when the communication device 1000 is used to implement the functions of the terminal in the method embodiments shown in Figures 2 to 6, the communication device 1000 can determine the second server that provides the corresponding service to the terminal based on the first correspondence when initiating the first service. The UE does not need to re-initiate the DNS process, but can determine the second server based on the first correspondence, which optimizes the process of UE reselecting EAS, thereby reducing satellite-to-ground interaction and reducing communication overhead.

[0435] When the communication device 1000 is used to implement the function of the first satellite in the method embodiments shown in Figures 7 to 9: the processing unit 1010 is used to obtain a third correspondence; the third correspondence is the address of the local domain name system server, or the third correspondence includes the correspondence between the local domain name system server and the data network name; the local domain name system server is associated with the first satellite. The transceiver unit 1020 is used to send the third correspondence.

[0436] In one possible implementation, when the third correspondence is the address of the local domain name system server, the processing unit 1010 is used to obtain the address of the local domain name system server and send the address of the local domain name system server.

[0437] In one possible implementation, the local domain name system server is deployed on the first satellite; or, the local domain name system server is deployed on the second satellite, which is a satellite with the local domain name system server deployed and connected to the first satellite; or, the local domain name system server is deployed on the second satellite, which is a satellite with the local domain name system server deployed and is the closest to the first satellite.

[0438] In one possible implementation, the first satellite broadcasts the third correspondence, or the first satellite sends the third correspondence to the terminal via an RRC message, and the terminal accesses the first satellite.

[0439] In one possible implementation, the first satellite broadcasting the third correspondence may be a first satellite sending a MIB or System Message Block (SIB) message, which includes the third correspondence.

[0440] In one possible implementation, the transceiver unit 1020 is used to receive a second message, which requests the address of a local domain name system server deployed on the first satellite. The transceiver unit 1020 is also used to send a third mapping relationship to the terminal via an RRC message.

[0441] In one possible implementation, the third correspondence includes at least one of the following:

[0442] The mapping between one or more satellites, one or more data network names, and local domain name system servers;

[0443] The mapping between time, one or more data network names, and the local domain name system server;

[0444] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0445] As can be seen, when the communication device 1000 is used to implement the function of the first satellite in the method embodiments shown in Figures 7 to 9, the communication device 1000 can determine the third correspondence and send the third correspondence to the terminal, thereby optimizing the UE reselection of EAS process, reducing satellite-to-ground interaction and reducing communication overhead.

[0446] When the communication device 1000 is used to implement the terminal functions in the method embodiments shown in Figures 7 to 9: the transceiver unit 1020 is used to receive a third correspondence, which is the address of the local domain name system server, or the third correspondence includes a correspondence between the local domain name system server and the data network name. The transceiver unit 1020 is also used to send a local domain name system query message to the local domain name system server when performing business.

[0447] In one possible implementation, the local domain name system server is deployed on the first satellite to which the terminal accesses; or, the local domain name system server is deployed on a second satellite, which is a satellite with the local domain name system server deployed and connected to the first satellite; or, the local domain name system server is deployed on a second satellite, which is a satellite with the local domain name system server deployed and is the closest to the first satellite.

[0448] In one possible implementation, the transceiver unit 1020 is configured to send a second message to the first satellite, the second message being a request to obtain the address of a local domain name system server deployed on the first satellite. The transceiver unit 1020 is also configured to receive an RRC message from the first satellite, the RRC message including a third mapping relationship.

[0449] In one possible implementation, the third correspondence includes at least one of the following:

[0450] The mapping between one or more satellites, one or more data network names, and local domain name system servers;

[0451] The mapping between time, one or more data network names, and the local domain name system server;

[0452] In one possible implementation, one or more satellites include a first satellite; time includes the current moment.

[0453] As can be seen, when the communication device 1000 is used to implement the terminal function in the method embodiments shown in Figures 7 to 9, the communication device 1000 can determine the local domain name system server used when accessing services based on the received third correspondence, and then obtain the corresponding application server, thereby reducing satellite-to-ground interaction and reducing communication overhead.

[0454] Optionally, a more detailed description of the above-mentioned processing unit 1010 and transceiver unit 1020 can be found in the relevant descriptions in the method embodiments shown in Figures 2 to 9.

[0455] As shown in Figure 11, the communication device 1100 includes one or more processors 1110 and interface circuitry 1120. The one or more processors 1110 and interface circuitry 1120 are coupled to each other. It is understood that interface circuitry 1120 can be a transceiver or an input / output interface. Optionally, the communication device 1100 may also include a memory 1130 for storing instructions executed by one or more processors 1110, or storing input data required for executing instructions by one or more processors 1110, or storing data generated after one or more processors 1110 execute instructions. Sometimes, interface circuitry 1120 can also be understood as part of one or more processors 1110, in which case the communication device 1100 includes one or more processors 1110. Optionally, the transceiver includes a transmitter and a receiver.

[0456] When the communication device 1100 is used to implement the method embodiments shown in Figures 2 to 9, one or more processors 1110 are used to implement the functions of the processing unit 1010, and the interface circuit 1120 is used to implement the functions of the transceiver unit 1020.

[0457] A transceiver provides a communication interface or means for communicating with various other devices via a wireless transmission medium. The transceiver may be coupled to an antenna array, and the transceiver and antenna array may be used together to communicate with a corresponding network type. One or more interfaces (e.g., a network interface and / or a user interface) provide a communication interface or means for communication via an internal bus or via an external transmission medium.

[0458] The processor is responsible for managing the bus and general processing, including executing software stored on a computer-readable medium. When executed by the processor, the software causes the processing system to perform the various functions described below for any particular device. Functions that can be implemented by the processor, memory, and computer-readable medium may include: encoding, decoding, rate matching, rate dematching, scrambling, descrambling, modulation, demodulation, layer mapping, fast Fourier transform (FFT), inverse fast Fourier transform (IFFT), inverse discrete Fourier transform (IDFT), precoding, resource element (RE) mapping, channel equalization, RE demapping, digital beamforming (BF), adding CP, removing CP, and so on.

[0459] In this application, entity A sends information to entity B, either directly or indirectly through other entities. Similarly, entity B receives information from entity A, either directly or indirectly through other entities. Entities A and B can be RAN nodes or terminals, or modules within RAN nodes or terminals. Information transmission and reception can be between RAN nodes and terminals, such as between a base station and a terminal; between two RAN nodes, such as between a CU and a DU; or between different modules within a single device, such as between a terminal chip and other modules of the terminal, or between a base station chip and other modules of the base station.

[0460] In other words, sending and receiving can occur between devices, such as between network devices and terminal devices, or within a device, such as between components, modules, chips, software modules, or hardware modules within the device via buses, wiring, or interfaces.

[0461] It is understandable that information may undergo necessary processing, such as encoding and modulation, between the source and destination, but the destination can understand the valid information from the source. Similar statements in this application can be interpreted in a similar way and will not be elaborated further.

[0462] This application also provides a communication system, which includes one or more of a first device or a second device. A first network element is used to perform all or part of the steps performed by the first network element in the preceding embodiments. A second network element is used to perform all or part of the steps performed by the second network element in the preceding embodiments. A terminal is used to perform all or part of the steps performed by the terminal in the preceding embodiments. An access network device is used to perform all or part of the steps performed by the access network device in the preceding embodiments.

[0463] This application provides a computer-readable storage medium. The computer-readable storage medium stores a program or instructions. When the program or instructions are executed on a computer, the computer performs the communication method shown in the embodiments illustrated in Figures 2 to 9.

[0464] This application provides a computer program product. The computer program product includes instructions. When the instructions are executed on a computer, the computer performs the communication method shown in the embodiments illustrated in Figures 2 to 9.

[0465] This application provides a chip or chip system including one or more processors and one or more interfaces, the one or more interfaces and one or more processors being interconnected via lines, and the one or more processors being used to run computer programs or instructions to perform the communication methods shown in the embodiments of Figures 2 to 9.

[0466] The interfaces in the chip can be input / output interfaces, pins, or circuits, etc.

[0467] The aforementioned chip system can be a System-on-a-Chip (SoC) or a baseband chip, etc. The baseband chip can include a processor, channel encoder, digital signal processor, modem, and interface module, etc.

[0468] In one possible implementation, the chip or chip system described above in this application further includes one or more memories storing instructions. The one or more memories can be internal storage units of the chip, such as registers, caches, etc., or they can be storage units of the chip itself (e.g., read-only memory, random access memory, etc.).

[0469] In one possible implementation, the chip architecture provided in this application includes a CU, a DU, and a RU. The CU performs layer 2 (L2) and layer 3 (L3) functions. Midhaul and backhaul interfaces are used to carry traffic between the CU and DU, as well as between the CU and the core network. The DU performs layer 1 (L1) and some L2 functions, while the RU performs L1 computation and RF digital functions. Fronthaul and backhaul interfaces are used to carry traffic between the RU and DU, as well as between the CU and DU. An integrated DU includes the aforementioned DU and RU functions.

[0470] The CU / DU hardware includes a chassis platform, motherboard, peripherals, and cooling system. The motherboard contains processing units, memory, internal I / O interfaces, and external connection ports. Its hardware accelerator is designed with interfaces, and hardware functional components include: storage for software, hardware, and system debugging interfaces, and a single-board management controller.

[0471] DU systems are typically implemented using multi-core processors and one or more hardware accelerators. Parts of the DU protocol stack can be implemented in software running on the multi-core processor, while computationally intensive L1 and L2 functions can be offloaded to a field-programmable gate array (FPGA) / graphics processing unit (GPU)-based hardware accelerator; alternatively, all L1 functions can be offloaded to an FPGA / GPU-based hardware accelerator, while other protocol stack components are implemented in software running on the processor; or the entire protocol stack can be implemented in software running on the processor. The hardware accelerator supports interconnection with x86 or non-x86 processors. Similarly, the accelerator has a multi-channel PCIe interface pointing to the central processing unit (CPU) and external connections via GbE.

[0472] The RU comprises three parts: the O-RAN processing unit (OPU), which receives eCPRI frames from the O-RAN fronthaul and performs fronthaul interface operations, the lowest level L1 (encoding, scrambling, modulation, layer mapping, precoding), synchronization, beamforming, and resource unit mapping. The OPU can be implemented as a CPU, FPGA, or application-specific integrated circuit (ASIC). The O-RU's digital processing unit (DPU) performs synchronization, digital downconversions (DDC) in the UL, and digital upconversions (DUC) in the DL, improving power amplifier efficiency by reducing the peak-to-average power ratio (PAPR) / adjacent channel leakage ratio (ACLR) of the RF front-end; the DPU can be implemented as an FPGA or ASIC. The O-RU's RF processing unit includes a transceiver module, up / down converters, power amplifiers (PA), low-noise amplifiers (LNA), and transmit / receive (Tx / Rx) filters. All conversions between the analog and digital domains (such as digital-to-analog converters (DACs) and analog-to-digital converters (ADCs)). Note that physical and logical partitions within the RF processing unit do not require specific boundaries.

[0473] The method steps in the embodiments of this application can be implemented in hardware or in software instructions executable by a processor. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. The storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Alternatively, the ASIC can reside in a base station or terminal. The processor and storage medium can also exist as discrete components in a base station or terminal.

[0474] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0475] In the various embodiments of 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. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0476] In this application, "one or more" means one or more, and "more than" 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 represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates an "or" relationship between the preceding and following related objects; in the formulas of this application, the character " / " indicates a "division" relationship between the preceding and following related objects. "Including one or more of A, B, and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B, and C.

[0477] In this application, terms such as "first" and "second" may be used to distinguish technical features that have the same or similar functions. The terms "first" and "second" do not limit the number or execution order, nor do they necessarily imply that they are different.

[0478] In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" should not be construed as being more preferred or advantageous than other embodiments or designs. The use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0479] It is understood that in this application, “when…”, “…when…”, and “if” all refer to the corresponding processing that will be carried out under certain objective circumstances, and are not time-limited, nor do they require a judgment action when implemented, nor do they imply any other limitations.

[0480] It is understood that some optional features in the embodiments of this application can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the apparatus given in the embodiments of this application can also implement these features or functions, which will not be elaborated here.

[0481] In the embodiments of this application, "instruction" can include direct and indirect instructions, as well as explicit and implicit instructions. The information indicated by a certain piece of information (hereinafter referred to as instruction information) is called the information to be instructed. In specific implementation, there are many ways to indicate the information to be instructed, such as, but not limited to, directly indicating the information to be instructed, such as the information to be instructed itself or its index. It can also indirectly indicate the information to be instructed by indicating other information, where there is an association between the other information and the information to be instructed; or it can indicate only a part of the information to be instructed, while the other parts are known or pre-agreed upon. For example, the instruction can be implemented by using a pre-agreed (e.g., protocol predefined) arrangement of various information, thereby reducing the instruction overhead to a certain extent. This application does not limit the specific method of instruction. It is understood that for the sender of the instruction information, the instruction information can be used to indicate the information to be instructed; for the receiver of the instruction information, the instruction information can be used to determine the information to be instructed.

[0482] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

Claims

1. A communication method, characterized in that, The method includes: The first network element determines the information of the first server based on the ephemeris information and the first location information of the terminal. The information of the first server includes a local domain name system server or one or more application servers corresponding to services. The first network element sends information from the first server to the terminal; the information from the first server is related to the first satellite accessed by the terminal.

2. The method according to claim 1, characterized in that, Before the first network element determines the first server based on ephemeris information and the terminal's first location information, the method further includes: The first network element determines that the terminal accesses the network via a non-terrestrial network.

3. The method according to claim 2, characterized in that, The first network element determines that the terminal accesses the network via a non-terrestrial network, including: The first network element receives first indication information, which is used to instruct the terminal to access the first satellite.

4. The method according to any one of claims 1 to 3, characterized in that, The information of the first server constitutes a first correspondence; the first correspondence includes at least one of the following: The mapping relationship between one or more satellites and local domain name system servers; The correspondence between one or more satellites, one or more business domain names, and the application servers corresponding to the one or more business domain names; The correspondence between time and the local domain name system server; The correspondence between time, one or more business domain names, and the application servers corresponding to the one or more business domain names; The mapping between one or more satellites, one or more data network names, and local domain name system servers; The correspondence between one or more satellites, one or more data network names, one or more business domain names, and the application servers corresponding to the one or more business domain names; The mapping between time, one or more data network names, and the local domain name system server; The correspondence between time, one or more data network names, one or more business domain names, and the application servers corresponding to the one or more business domain names.

5. The method according to claim 4, characterized in that, The one or more satellites include the first satellite.

6. The method according to claim 4, characterized in that, The one or more times include a first time, which is the time when the first satellite provides services to the terminal.

7. The method according to any one of claims 4 to 6, characterized in that, The method further includes: The first network element determines the first correspondence based on one or more of the following: the first location information, the first service information of the terminal, the first satellite, and the ephemeris information; The first service information includes at least one of the following: data network name, network slice selection auxiliary information, and service domain name.

8. The method according to any one of claims 1 to 7, characterized in that, The information of the first server or the first correspondence is carried in the first message, which is any one of the following: session establishment acceptance message, session modification instruction, registration acceptance message, UE configuration update instruction.

9. The method according to any one of claims 1 to 8, characterized in that, The method further includes: When the location of the terminal changes, the first network element sends a second correspondence; the location information of the terminal after the change is different from the first location information. The first network element sends the second correspondence.

10. A communication method, characterized in that, The method includes: When a terminal initiates a first service, the terminal determines a second server based on a first correspondence. The second server includes an application server to be accessed or a local domain name system server. The application server to be accessed or the local domain name system server is deployed on a satellite. The terminal accesses the second server.

11. The method according to claim 10, characterized in that, The first correspondence includes one or more of the following: The mapping relationship between one or more satellites and local domain name system servers; The correspondence between one or more satellites, one or more business domain names, and the application servers corresponding to the one or more business domain names; The correspondence between time and the local domain name system server; The correspondence between time, one or more business domain names, and the application servers corresponding to the one or more business domain names; The mapping between one or more satellites, one or more data network names, and local domain name system servers; The correspondence between one or more satellites, one or more data network names, one or more business domain names, and the application servers corresponding to the one or more business domain names; The mapping between time, one or more data network names, and the local domain name system server; The correspondence between time, one or more data network names, one or more business domain names, and the application servers corresponding to the one or more business domain names.

12. The method according to claim 11, characterized in that, The terminal accesses a first satellite; the one or more satellites include the first satellite. The one or more times include a first time, which is the time when the first satellite provides services to the terminal.

13. The method according to claim 10, characterized in that, The terminal determines the second server based on the first correspondence, including: The terminal determines the second server based on the first correspondence and at least one of the following: At least one of the following includes the first service, service information corresponding to the first service, the first satellite accessed by the terminal, and the current time; The second server is a server deployed on the first or second satellite; The second satellite is one that has deployed an application server or a local domain name system server and is connected to the first satellite; or the second satellite is one that has deployed an application server or a local domain name system server and is the closest satellite to the first satellite.

14. The method according to any one of claims 11 to 13, characterized in that, Before the terminal determines the second server based on the first correspondence, the method further includes: The terminal receives a first message, the first message including the first correspondence; The first message is any one of the following: session establishment acceptance message, session modification instruction, registration acceptance message, UE configuration update instruction.

15. The method according to any one of claims 11 to 14, characterized in that, The method further includes: When the location of the terminal changes, the terminal receives a second correspondence; the changed location information of the terminal is different from the first location information.

16. A communication method, characterized in that, The method includes: The first satellite acquires a third correspondence; the third correspondence is the address of a local domain name system server, or the third correspondence includes the correspondence between the local domain name system server and the data network name; the local domain name system server is associated with the first satellite; The first satellite transmits the third correspondence.

17. The method according to claim 16, characterized in that, The local domain name system server is deployed on the first satellite; Alternatively, the local domain name system server may be deployed on a second satellite, which is a satellite with a local domain name system server deployed and connected to the first satellite; Alternatively, the local domain name system server may be deployed on a second satellite, which is the satellite with the local domain name system server deployed and is the closest to the first satellite.

18. The method according to claim 16, characterized in that, The first satellite transmits the third correspondence, including: The first satellite broadcasts the third correspondence, or, The first satellite sends the third correspondence to the terminal via Radio Resource Control (RRC) messages, and the terminal accesses the first satellite.

19. The method according to claim 16, characterized in that, The method further includes: The first satellite receives a second message, which is used to request the address of the local domain name system server deployed on the first satellite; The first satellite transmits the third correspondence, including: The first satellite sends the third correspondence to the terminal via an RRC message.

20. The method according to any one of claims 16 to 19, characterized in that, The third correspondence includes at least one of the following: The mapping between one or more satellites, one or more data network names, and local domain name system servers. The mapping between time, one or more data network names, and the local domain name system server.

21. A communication method, characterized in that, The method includes: The terminal receives a third correspondence, which is the address of the local domain name system server, or the third correspondence includes the correspondence between the local domain name system server and the data network name; When the terminal performs a service, it sends a local domain name system query message to the local domain name system server.

22. The method according to claim 21, characterized in that, The local domain name system server is deployed on the first satellite accessed by the terminal; Alternatively, the local domain name system server may be deployed on a second satellite, which is a satellite with a local domain name system server deployed and connected to the first satellite; Alternatively, the local domain name system server may be deployed on a second satellite, which is the satellite with the local domain name system server deployed and is the closest to the first satellite.

23. The method according to claim 21, characterized in that, The method further includes: The terminal sends a second message to the first satellite, the second message being used to request the address of the local domain name system server deployed on the first satellite; The terminal receives the third correspondence, including: The terminal receives an RRC message from the first satellite, the RRC message including the third correspondence.

24. The method according to any one of claims 21 to 23, characterized in that, The third correspondence includes at least one of the following: The mapping between one or more satellites, one or more data network names, and local domain name system servers. The mapping between time, one or more data network names, and the local domain name system server.

25. A communication device, characterized in that, It includes modules or units for performing the method as described in any one of claims 1 to 9, or modules or units for performing the method as described in any one of claims 10 to 15, or modules or units for performing the method as described in any one of claims 16 to 20, or modules or units for performing the method as described in any one of claims 21 to 24.

26. A communication device, characterized in that, The device includes a memory and one or more processors, the memory being used to store a computer program; the one or more processors being used to execute the computer program in the memory, causing the communication device to perform the method as described in any one of claims 1 to 9, 10 to 15, 16 to 20, or 21 to 24.

27. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instructions that, when executed by a communication device, implement the method as described in any one of claims 1 to 9, 10 to 15, 16 to 20, or 21 to 24.

28. A computer program product, characterized in that, Includes instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1 to 9, 10 to 15, 16 to 20, or 21 to 24.

29. A communication system, characterized in that, The communication system includes one or more of the following: means for performing the method according to any one of claims 1 to 9, means for performing the method according to any one of claims 10 to 15, means for performing the method according to any one of claims 16 to 20, and means for performing the method according to any one of claims 21 to 24.

30. A chip or chip system, characterized in that, Includes a processor for performing the method as described in any one of claims 1 to 9, 10 to 15, 16 to 20, or 21 to 24.

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