Satellite communication method, communication device and communication system

Abstract

The application provides a satellite communication method, a communication device and a communication system, and relates to the technical field of communication. The satellite communication method can comprise the following steps: an AMF sends a second paging message to a first satellite according to location area information of a terminal device and ephemeris information of a satellite, and then the first satellite sends a first paging message. After the terminal device receives the first paging message sent by the first satellite, the terminal device sends a connection establishment request to the first satellite. In this way, the first satellite used for paging the terminal device can be determined according to the location area information of the terminal device and the ephemeris information of the satellite, and then the first paging message is sent by the first satellite to page the terminal device. Since the location area information of the terminal device is updated along with the change of the location information of the terminal device, the first satellite used for paging the terminal device is not fixed, and therefore the probability of successfully paging the terminal device is improved.

Description

Technical Field

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

[0002] With the development of satellite communication technology, the cost of satellite launch and maintenance has dropped significantly, enabling major companies and institutions to develop and deploy large-scale satellite constellations to provide services worldwide. These satellite constellations can not only improve network access in remote areas and oceans, but also improve aviation and maritime communications.

[0003] In low-Earth orbit (LEO) satellite communication scenarios, fixed ground cells are used. This means that the same geographical area is continuously covered by a fixed beam at all times, and this coverage does not change as the satellite beam moves. However, in a fixed ground cell scenario, terminal devices do not update their location area due to cell changes during high-speed movement, causing the satellite to be unable to quickly page the terminal device. Summary of the Invention

[0004] This application provides a satellite communication method, communication device, and communication system. By determining the first satellite for paging the terminal device based on the location area information of the terminal device and the ephemeris information of the satellite, the first satellite for paging the terminal device may also change when the location area of ​​the terminal device is updated, thereby increasing the probability of successfully paging the terminal device.

[0005] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0006] Firstly, a satellite communication method is provided, applied to a terminal device. The method may include: after receiving a first paging message from a first satellite, the terminal device, in response to the first paging message, sends a connection establishment request to the first satellite. The first satellite is determined based on the location area information of the terminal device and the ephemeris information of the satellite; the first paging message is used to instruct the terminal device to establish a communication connection with the first satellite; the connection establishment request is used by the terminal device to request the establishment of a communication connection with the first satellite. The first satellite may be at least one of several satellites. The location area information of the terminal device is used to indicate the location area of ​​the terminal device.

[0007] In this implementation, the first satellite used for paging terminal equipment is determined based on the location area information of the terminal equipment and the ephemeris information of the satellite. When the location area of ​​the terminal equipment is updated, the first satellite used for paging terminal equipment may also change. Compared with using a fixed location area to paging terminal equipment, this increases the probability of successfully paging terminal equipment.

[0008] In one implementation of the first aspect, before receiving the first paging message from the first satellite, the method may further include: after the terminal device sends a registration request to the second satellite, receiving a registration response from the second satellite. The registration request is used to request the determination of the location area of ​​the terminal device; the second satellite is a satellite that provides services to the terminal device; and the registration response is used to indicate the location area of ​​the terminal device.

[0009] In this implementation, the terminal device can send a registration request to the second satellite to determine its location area. When the satellite pages the terminal device, it only pages within the location area, reducing the signaling overhead of the paging terminal.

[0010] In another implementation of the first aspect, the registration request includes initial position or speed information of the terminal device, which is used to determine the location area of ​​the terminal device.

[0011] In this implementation, the location area of ​​the terminal device can be quickly determined based on the initial position or velocity information of the terminal device, so that when the satellite pages the terminal device, it only pages within the location area, reducing the signaling overhead of the paging terminal.

[0012] In another implementation of the first aspect, before receiving the first paging message from the first satellite, the method may further include: if the terminal device's current location is not within the location area or the first timer has expired, the terminal device sends a registration update request to the second satellite and then receives a registration update response from the second satellite; wherein the registration update request is used to request an update of the terminal device's location area; the first timer is started when the terminal device receives the registration response; and the registration update response is used to indicate the updated location area.

[0013] In this implementation, in scenarios where the location area of ​​the terminal device is fixed in related technologies, if the radius of the location area corresponding to the terminal device's location area is small, the terminal device may frequently update its location area due to high-speed movement, resulting in high signaling overhead. In this embodiment, the terminal device requests an update to its location area only when it moves to the boundary of the location area or when the first timer expires. This avoids the situation where, in scenarios where the terminal device's location area is fixed, the small radius of the location area leads to frequent updates of location information and high signaling overhead.

[0014] In another implementation of the first aspect, the registration update request includes the current location and update time information of the terminal device, which are used to determine the updated location area.

[0015] In this implementation, the access and mobility management function (AMF) can determine the updated location area based on the current location and update time information of the terminal device. With the increase of the radius of the location area corresponding to the updated location area, it avoids the situation where the terminal device frequently updates its location information and causes a large signaling overhead when the location area radius is small in the scenario where the location area of ​​the terminal device is fixed.

[0016] In another implementation of the first aspect, the updated location area includes a circular region with the current location as the center and the radius of the updated location area as the radius; when the time difference is less than or equal to a preset duration, the radius of the updated location area is the product of the radius of the location area determined in the previous request and a first ratio, where the first ratio is the ratio of the preset duration to the time difference; or, when the time difference is greater than the preset duration, the radius of the updated location area is the radius of the location area of ​​the terminal device determined in the previous request.

[0017] The time difference is the time difference between the update time information and the last request on the terminal device to determine the location area, or the time difference is the time difference between the update time information and the first request on the terminal device to determine the location area, where the last request is the request with the shortest time interval from the registration update request.

[0018] In this implementation, when the time difference is less than or equal to the preset duration, the AMF increases the radius of the location area corresponding to the location area of ​​the terminal device. By increasing the radius of the location area, the situation where the location area radius of the terminal device is too small, causing the terminal device to frequently update the location area during movement and resulting in large signaling overhead is avoided.

[0019] In another implementation of the first aspect, the registration update request includes the speed information and update time information of the terminal device, which are used to determine the updated location area.

[0020] In this implementation, when the terminal device's speed is high, the AMF can determine that the radius of the updated location area is large; conversely, when the terminal device's speed is low, the AMF can determine that the radius of the updated location area is small. This avoids the situation where the terminal device's location area radius is small, leading to frequent location area updates during high-speed movement and resulting in high signaling overhead.

[0021] Secondly, a satellite communication method is provided, applied to an Access and Mobility Management Function (AMF) network element. This method may include: after receiving a paging request from a control center, the AMF, in response to the paging request, sends a second paging message to a first satellite based on the location area information of the terminal device and the ephemeris information of the satellite. The location area information of the terminal device is used to indicate the location area of ​​the terminal device.

[0022] In this implementation, the first satellite used for paging terminal equipment is determined by the AMF based on the latest location area of ​​the terminal equipment and the satellite's ephemeris information. The first satellite sends paging messages within the location area of ​​the terminal equipment, which increases the probability of successfully paging the terminal equipment.

[0023] In one implementation of the second aspect, the method may further include: after receiving a registration request from the second satellite, the AMF sends a registration response to the second satellite; wherein the registration request is used to request the determination of the location area of ​​the terminal device; and the registration response is used to indicate the location area of ​​the terminal device.

[0024] In this implementation, the AMF can receive a registration request from the second satellite. After determining the location area of ​​the terminal device, the AMF sends a registration response indicating the location area of ​​the terminal device to the second satellite. The AMF quickly determines the location area of ​​the terminal device. During the paging process, the satellite used for paging the terminal device can be determined based on the location area of ​​the terminal device, which helps to increase the probability of successfully paging the terminal device.

[0025] In another implementation of the second aspect, the registration request includes initial position or speed information of the terminal device, which is used to determine the location area of ​​the terminal device.

[0026] In this implementation, the AMF can quickly determine the location area of ​​the terminal device based on its initial position or velocity information. This way, when the satellite pages the terminal device, it only pages within that location area, reducing the signaling overhead of the paging terminal.

[0027] In another implementation of the second aspect, the method may further include: after receiving a registration update request from the second satellite, the AMF sends a registration update response to the second satellite; wherein the registration update request is used to request an update of the location area of ​​the terminal device; and the registration update response is used to indicate the updated location area.

[0028] In this implementation, after the AMF receives the registration update request relayed by the second satellite, it determines the updated location area. With the radius of the location area corresponding to the updated location area increasing, it avoids the situation where the radius of the location area corresponding to the fixed location area of ​​the terminal device is small, which would cause the terminal device to frequently update the location information and result in a large signaling overhead.

[0029] In another implementation of the second aspect, the registration update request includes the current location and update time information of the terminal device, which are used to determine the updated location area.

[0030] In this implementation, the AMF can determine the updated location area based on the current location and update time information of the terminal device. With the increase of the radius of the location area corresponding to the updated location area, it avoids the situation where the terminal device frequently updates its location and the radius of the location area corresponding to the fixed location area, resulting in a large signaling overhead.

[0031] In another implementation of the second aspect, the updated location area includes a circular region with the current location as the center and the radius of the updated location area as the radius; when the time difference is less than or equal to a preset duration, the radius of the updated location area is the product of the radius of the location area determined in the previous request and a first ratio, where the first ratio is the ratio of the preset duration to the time difference; or, when the time difference is greater than the preset duration, the radius of the updated location area is the radius of the location area of ​​the terminal device determined in the previous request.

[0032] The time difference is the time difference between the update time information and the last request on the terminal device to determine the location area, or the time difference is the time difference between the update time information and the first request on the terminal device to determine the location area, where the last request is the request with the shortest time interval from the registration update request.

[0033] In this implementation, when the time difference is less than or equal to the preset duration, the AMF increases the radius of the location area corresponding to the location area of ​​the terminal device. By increasing the radius of the location area, the terminal device avoids having too small a radius of location area, which would cause the terminal device to frequently update the location area during movement, resulting in a large signaling overhead.

[0034] In another implementation of the second aspect, the registration update request includes the speed information and update time information of the terminal device, which are used to determine the updated location area.

[0035] In this implementation, when the terminal device's speed is high, the AMF can determine that the radius of the updated location area is large; conversely, when the terminal device's speed is low, the AMF can determine that the radius of the updated location area is small. This avoids the situation where the terminal device's location area radius is small, leading to frequent location area updates during high-speed movement and resulting in high signaling overhead.

[0036] Thirdly, a satellite communication method is provided, applied to a first satellite. The method may include: the first satellite receiving a second paging message from an AMF (Advanced Message Support Unit); the first satellite sending a first paging message; wherein the first paging message is used to instruct a terminal device to establish a communication connection with the first satellite; and receiving a connection establishment request sent by the terminal device; wherein the connection establishment request is used to request the establishment of a communication connection with the first satellite.

[0037] In this implementation, the first satellite is determined by the AMF based on the latest location area of ​​the terminal device. Using the first satellite to send the first paging message can increase the probability of successfully paging the terminal device.

[0038] In one implementation of the third aspect, sending the first paging message may include: starting a second timer; and sending the first paging message during the operation of the second timer.

[0039] In this implementation, the first satellite sends a first paging message during the second timer's operation until it receives a connection establishment request from the terminal device. This avoids the situation where the first satellite spends a long time sending the first paging message, resulting in high signaling overhead.

[0040] In another implementation of the third aspect, the method may further include: if no connection establishment request is received from the terminal device after the second timer expires, then the first paging message is sent again.

[0041] In this implementation, the first satellite pages the terminal device multiple times, and each time it pages the terminal device during the second timer operation. This not only avoids the situation of large paging signaling overhead, but also increases the probability of successfully paging the terminal device.

[0042] In another implementation of the third aspect, the first satellite corresponds to multiple target beams, and the first satellite sends a first paging message, including: according to the order of the coverage range of the multiple target beams from large to small and / or the order of the number of terminal devices covered by the multiple beams from large to small, the first paging message is sent sequentially using multiple target beams.

[0043] In this implementation, the first satellite uses multiple target beams to sequentially send the first paging message to the terminal device. Once the terminal device is successfully paged, the subsequent paging process can be stopped, thus reducing paging overhead.

[0044] Fourthly, a satellite communication method is provided, applied to a second satellite. This method may include: after receiving a registration request from a terminal device, the second satellite sends a registration request to the AMF; then, after receiving a registration response from the AMF, the second satellite sends a registration response to the terminal device. The registration request is used to request the determination of the location area of ​​the terminal device; the registration response is used to indicate the location area of ​​the terminal device.

[0045] In one implementation of the fourth aspect, the method further includes: after receiving a registration update request from the terminal device, the second satellite sends a registration update request to the AMF. Then, after receiving a registration update response from the AMF, the second satellite sends a registration update response to the terminal device. The registration update request is used to request an update of the terminal device's location area; the registration update response is used to indicate the updated location area.

[0046] Fifthly, this application provides a communication device including one or more processors, a memory, and a computer program stored in the memory, wherein the processor executes the computer program to implement at least one method described in the embodiments of the first to fourth aspects above.

[0047] In a sixth aspect, this application provides a communication system comprising a terminal device, a ground station, a first satellite, and a second satellite. The terminal device is configured to perform the method described in the first aspect embodiment, the ground station is configured to perform the method described in the second aspect embodiment, the first satellite is configured to perform the method described in the third aspect embodiment, and the second satellite is configured to perform the method described in the fourth aspect embodiment.

[0048] In a seventh aspect, this application provides a computer-readable storage medium having a computer program / instructions stored thereon, which, when executed by a processor, implements the method described in the first aspect embodiment, or implements the method described in the second aspect embodiment, or implements the method described in the third aspect embodiment, or implements the method described in the fourth aspect embodiment.

[0049] Eighthly, this application provides a chip system including a memory and a processor, wherein a program / instruction stored in the memory is executed by the processor to implement the method described in the first aspect embodiment, or to implement the method described in the second aspect embodiment, or to implement the method described in the third aspect embodiment, or to implement the method described in the fourth aspect embodiment.

[0050] Ninthly, this application provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the method described in the first aspect embodiment, or implement the method described in the second aspect embodiment, or implement the method described in the third aspect embodiment, or implement the method described in the fourth aspect embodiment.

[0051] It is understood that the communication device described in the fifth aspect, the communication system described in the sixth aspect, the computer-readable storage medium described in the seventh aspect, the chip system described in the eighth aspect, and the computer program product described in the ninth aspect are all used to execute the corresponding methods provided above. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods provided above, and will not be repeated here. Attached Figure Description

[0052] Figure 1 Example diagram showing the coverage of a fixed ground cell by the same satellite at different times;

[0053] Figure 2 A schematic diagram illustrating the paging process for terminal devices provided by existing technology;

[0054] Figure 3 Example diagram comparing ground location areas and non-ground network location areas;

[0055] Figure 4 This is a schematic diagram of tracking area list management provided in an embodiment of this application;

[0056] Figure 5 This application provides a location area update scenario diagram for its embodiments.

[0057] Figure 6 A scene diagram illustrating the updated tracking area list provided in this application embodiment;

[0058] Figure 7 An application scenario diagram of a satellite communication system provided in this application embodiment;

[0059] Figure 8 A diagram illustrating the satellite communication method provided in the embodiments of this application;

[0060] Figure 9 A schematic flowchart illustrating a satellite communication method provided in an embodiment of this application;

[0061] Figure 10 An example diagram of the elevation angle of a satellite provided in an embodiment of this application;

[0062] Figure 11 This application provides a schematic diagram of a signaling interaction process for determining the location area of ​​a terminal device.

[0063] Figure 12 Example diagram of the location area of ​​the terminal device provided in the embodiments of this application;

[0064] Figure 13 This application provides a schematic diagram of a signaling interaction process for updating the location area of ​​a terminal device.

[0065] Figure 14 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0066] Figure 15 This is a schematic diagram of the structure of a communication system provided in an embodiment of this application. Detailed Implementation

[0067] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B; the term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone.

[0068] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0069] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0070] First, to facilitate understanding of the methods provided in this application, the technical terms involved in this application will be explained.

[0071] 1. Non-terrestrial networks (NTNs) are a general term for networks involving flying objects. They achieve wireless communication through satellite or drone platforms, providing ubiquitous coverage for terminal devices regardless of terrain. In particular, NTNs can be used to improve network coverage in areas where terrestrial network equipment is not readily available, such as deserts, oceans, and high-altitude regions. NTNs can include satellite communication systems, high-altitude platform systems (HAPS), and air-to-ground networks. Satellite communication systems rely on onboard platforms, primarily including low-Earth orbit (LEO), medium-Earth orbit (MEO), and geostationary earth orbit (GEO) satellites.

[0072] 2. Low Earth Orbit (LEO) satellites: These are satellites that operate in orbits relatively close to the Earth's surface. Because the coverage area of ​​a single LEO satellite is relatively small, there may be scenarios where a LEO satellite cannot simultaneously connect to terminal equipment and ground stations.

[0073] In the NTN scenario, satellite communication systems have two typical architectures: transparent payload and regenerative payload.

[0074] In a transparent transmission architecture, the satellite is responsible for data forwarding but has no data processing capabilities. In an NTN scenario, the access network equipment is located on the ground, and the satellite connects to the access network equipment through a ground station (or gateway station). Data sent from the terminal equipment to the satellite is forwarded by the satellite to the access network equipment, where it is processed. The link between the satellite and the terminal equipment is a service link, and the link between the satellite and the ground station is a feeder link.

[0075] In a regenerative architecture, the satellite possesses all or some of the functions of a base station, meaning it can perform data processing. Data sent from terminal devices to the satellite is processed by the satellite. The link between the satellite and the terminal device is a service link.

[0076] For example, Table 1 below shows the classification of NTN scenarios based on satellite type and network characteristics.

[0077] Table 1

[0078] Transmitted satellite Regenerated Satellite GEO-based non-terrestrial access network Scenario A Scene B Non-terrestrial access networks based on movable beam LEO Scene C1 Scene D1 LEO-based non-terrestrial access networks: Beams move with satellites Scene C2 Scene D2

[0079] In NTN scenarios, satellites are in high-speed motion relative to terminal devices, resulting in a high rate of change in the relative position and velocity between the terminal devices and satellites. Terminal devices need to calculate the satellite's position and / or velocity in real time based on satellite ephemeris information, and calculate relevant parameters such as Doppler frequency offset, timing advance (TA), and propagation delay. Based on these parameters, the terminal devices' receiving and transmitting parameters are calibrated to ensure normal uplink and downlink access. Ground stations also need to determine the satellites and beam information covering the terminal devices based on their location information and satellite ephemeris information.

[0080] Satellite ephemeris information, also known as ephemeris tables, almanacs, or almanacs, is used to provide terminal equipment or ground stations with the instantaneous status of satellites and / or satellites. In other words, ephemeris information is used to determine the satellite's position at any given moment. Ephemeris information refers to information related to satellite constellations, which can be broadly categorized as the satellite's three-dimensional spatial position, velocity state vector information, and orbital information. Specifically, this information can be divided into satellite position and velocity state vectors, orbital plane parameters, and satellite layer parameters.

[0081] 3. Fixed ground cell: This refers to a cell or area covered by a satellite beam that remains fixed on the ground and does not change as the satellite beam moves. In other words, the same geographical area is continuously covered by a fixed beam at all times.

[0082] For example, Figure 1 This is an example diagram showing the coverage of a fixed ground cell by the same satellite at different times. (Example:) Figure 1 As shown, at time t0, the satellite's current coverage area is a circle containing cells numbered 1, 2, and 3. These cells are located within a smaller circular area, representing the satellite's current coverage. At time t0+t1, the satellite's position changes, causing its coverage area to shift accordingly. The area containing cells numbered 1, 2, and 3 remains within the satellite's coverage. At time t0+2*t1, the satellite's coverage continues to shift, but cells numbered 1, 2, and 3 remain within the smaller circle. It is evident that as the coverage area of ​​the serving satellite changes, the fixed ground cells are continuously covered by a fixed beam and do not change with the movement of the serving satellite's beam.

[0083] 4. Location area of ​​the terminal device: This is the location area where the terminal device is currently located. The location area of ​​the terminal device is indicated by location area information.

[0084] In this embodiment, the shape of the location area of ​​the terminal device is not limited; the location area can be circular, elliptical, or regular hexagonal, etc. For example, the location area of ​​the terminal device can be a circular region with the location of the terminal device as the center and the radius of the location area as the radius. The radius of the location area refers to the radius of the location area of ​​the terminal device. The location area information of the terminal device may include a location area code used to uniquely identify the location area. The location area code is an identifier used to uniquely define a location area in a communication system.

[0085] When a satellite establishes a communication connection with a terminal device, the satellite can broadcast paging messages within the terminal device's location area to page the terminal device. When the terminal device moves from one location area to another, it can request an update of its location area to ensure that the satellite can page the terminal device.

[0086] 5. Mobility Management: This is one of the core functions of mobile communication networks, including location management and handover management. Location management in NTN scenarios is of great significance for improving user experience and service continuity.

[0087] According to the 3rd Generation Partnership Project (3GPP), mobility management for fixed terrestrial cells typically employs a location-triggered handover mechanism. This requires terminal equipment to have a certain degree of self-positioning capability. As specified in 3GPP Rel-17, NTN users need to have Global Navigation Satellite System (GNSS) capability; therefore, terminal equipment must know its own location information, and reporting this location information can better assist the network in mobility management.

[0088] In low-Earth orbit (LEO) satellite communication scenarios, terminal devices frequently trigger location information updates due to fixed location area division strategies. Fixed location area division refers to dividing each location area into boundaries based on a pre-defined area size. When a terminal device crosses a location area boundary, it triggers a location information update. When a satellite pages a terminal device, it can send a paging message based on the terminal device's location. When the radius of a terminal device's fixed location area is small, the terminal device at the location area boundary may move back and forth between two or more location areas, causing a "ping-pong effect." Furthermore, high-speed movement of the terminal device increases the overhead of location update signaling.

[0089] For example, Figure 2 A schematic diagram illustrating the paging process for terminal devices, provided for reference in existing technologies. For example... Figure 2As shown, the terminal device sends its location information to satellite 1. Here, the terminal device's location information refers to the latitude and longitude information corresponding to its current location. When the feeder link between satellite 1 and the ground station is connected, satellite 1 can directly send the terminal device's location information to the access and mobility management function (AMF). When satellite 1 cannot simultaneously connect the terminal device and the ground station, the terminal device's location information can be sent to the AMF via multi-satellite relay. For example, satellite 1 sends the received terminal device's location information to satellite 2, and satellite 2 sends the terminal device's location information to the AMF. After receiving the terminal device's location information, the AMF stores it. Then, the AMF determines the satellite to page the terminal based on the stored location information. That is, the AMF determines which satellite to page the terminal device on. For example, if the AMF determines to page the terminal device on satellite 2, the AMF sends a paging message to satellite 2 to initiate paging through satellite 2. If the AMF determines that a paging request will be made to the terminal device on satellite 3, the AMF will send a paging message to satellite 3 to initiate paging through satellite 3.

[0090] The high mobility of terminal devices and the large coverage area of ​​satellite beams both impact mobility management. In fixed terrestrial cells, excessively fast movement of terminal devices leads to frequent location area updates. However, current satellite paging systems do not account for changes in the terminal's location area, resulting in inefficient paging by the satellite, increased signaling overhead between the terminal and the satellite, and consequently, disruption of service transmission and a poor user experience.

[0091] Currently, drawing on the issue of frequent location area updates for terminal devices in 5G terrestrial mobile communication technology scenarios, technicians have adopted a location area partitioning and update scheme based on a tracking area list (TAL). For example, in a 5G scenario, during registration, a terminal device obtains one or more tracking areas (TAs) allocated by the core network as its location area list. When the terminal device moves out of the location area list, a location update is triggered. After receiving the TAL contained in the system information block (SIB1) broadcast by the network device, the terminal device compares the received TAL information with its own stored TAL information. When the terminal device determines that the received TAL information differs from its stored TAL information, it updates the TAL information.

[0092] However, unlike the cell and TA planning in terrestrial cellular communications, the coverage area of ​​a single cell in satellite communications may encompass multiple TAs; that is, the coverage area of ​​a cell in an NTN scenario is larger than that of a cell in a terrestrial scenario. For example, Figure 3 Example diagram comparing the location areas of ground-based and non-ground-based networks. Figure 3 (a) is an example diagram showing the ratio of TA to cell in the ground location area. Figure 3 (b) is an example diagram showing the ratio of TA to cell in the NTN location area. Figure 3 It is known that simply increasing the TA in NTN to the ratio of TA to cell size in a ground-based scenario may lead to a larger paging range for satellite paging terminals, ultimately resulting in a significant increase in paging overhead. Furthermore, many current satellite communication systems are multi-layered, with varying cell sizes within each layer. Simply increasing the TA cannot solve the problem of large satellite coverage areas causing terminal devices to be unable to accurately determine their location and resulting in uncertain paging ranges. For example, due to the large coverage areas of cells in NTN scenarios, in overlapping coverage areas of multiple cells, a terminal device may receive different TA identifiers from two cells. Figure 4 The cross-coverage range shown may result in terminal devices receiving TAL identification information from both TA list 1 and TA list 2, making it impossible for the terminal devices to determine which TAL to use for network registration and location updates.

[0093] In addition, in the related technologies, for the NTN scenario of regenerative satellites, there is a situation where the switching of the satellite's power supply link causes changes in the management function entity, which in turn leads to the update of the location area.

[0094] It should be understood that in the 4G scenario, the management function entity can be the access and mobility management entity (MME), while in the 5G scenario, the management function entity can be the AMF.

[0095] For example, such as Figure 5 As shown, assuming that at time T0, the satellite connects to the source MME of the ground station via feed link 1, and at time T1, the satellite's position changes, and the satellite connects to the target MME of the ground station via feed link 2. It is evident that the change transmitted by the MME of the ground station connected to the satellite triggers a position area update.

[0096] When LEO satellites move in orbits relatively close to the Earth's surface, the radio access network (RAN) calculates the satellite's coverage area using ephemeris information to avoid sending paging requests when terminal devices are not covered by the satellite. Furthermore, the RAN can periodically update the TA list based on the satellite's orbit and coverage area without frequently reporting to the ground station, reducing unnecessary message interactions. For example, ... Figure 6 As shown, at time T1 or T2, the feed link between the satellite and ground station 1 is connected; at time T3 or T4, the feed link between the satellite and ground station 2 is connected; and at time T5 or T6, the feed link between the satellite and ground station 3 is connected. When the RAN determines that the satellite's coverage area has been updated, it triggers an update to the satellite's TA list. Therefore, when the satellite moves to different locations at different times, the RAN periodically updates the satellite's TA list to reduce signaling interaction between the satellite and the ground station.

[0097] As can be seen from the above, the existing technology does not consider the problem of frequent updates to the location area of ​​the terminal device caused by the movement of the terminal device in the NTN scenario. Even if the location update method and paging method in the existing terrestrial cellular communication are adopted in the NTN scenario, it cannot effectively solve the problem of frequent updates to the location area of ​​the terminal device in the NTN scenario. Furthermore, if the location area of ​​the terminal device is not updated in the NTN scenario, and the satellite is paging the terminal device in a fixed location area, it will lead to a low success rate of paging the terminal device. Based on this, the embodiments of this application provide a satellite communication method. The method is applied to a satellite communication system. The method may include, when it is necessary to paging the terminal device, the AMF determines the first satellite for paging the terminal device based on the latest location area information of the terminal device and the ephemeris information of the satellite, and the first satellite sends a paging message. When the first satellite receives the connection establishment request sent by the terminal device, it determines that the terminal device has been successfully paged. Since the location information of the terminal device changes during the movement of the terminal device, the location area information of the terminal device is updated. Consequently, the first satellite determined by the AMF for paging the terminal device based on the location area information of the terminal device and the ephemeris information of the satellite will also change. In this way, the AMF determines the first satellite to page the terminal device based on the latest location area of ​​the terminal device and the ephemeris information of the satellite. The first satellite then sends a paging message to page the terminal device, which increases the probability of successfully paging the terminal device and reduces paging overhead to a certain extent.

[0098] The satellite communication method provided in the embodiments of this application will be described below with reference to the accompanying drawings.

[0099] The technical methods of this application embodiment can be used in various communication systems in satellite communication scenarios. These communication systems can be third-generation partnership project (3GPP) communication systems, such as long-term evolution (LTE) systems, fifth-generation (5G) mobile communication systems, new radio (NR) systems, vehicle-to-everything (NRV2X) systems, and can also be applied to LTE and 5G hybrid networking systems, or wireless fidelity (WiFi) systems, device-to-device (D2D) communication systems, machine-to-machine (M2M) communication systems, integrated access and backhaul (IBA) communication systems, Internet of Things (IoT), etc.

[0100] The technical solutions provided in this application can also be applied to future communication systems, such as the sixth-generation mobile communication system, or to non-3GPP communication systems. This application does not limit the application in this regard.

[0101] The technical solutions of this application can be applied to various communication scenarios, such as one or more of the following communication scenarios: enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), machine type communication (MTC), massive machine type communications (mMTC), D2D, V2X, and IoT communication scenarios.

[0102] For example, Figure 7 This is an application scenario diagram of a satellite communication system provided in an embodiment of this application. The satellite communication method provided in this embodiment can be applied to... Figure 7 The satellite communication system in the middle may include terminal equipment 710, multiple satellites (e.g., Figure 7 (including satellites 1 and 2, etc.) and ground station 720.

[0103] The satellites in this application embodiment can be devices with signal transceiver capabilities on various satellites controlled from outer space. Examples include Global Positioning System satellites, BeiDou satellites, and communication satellites from various operators. These multiple satellites can communicate with each other via inter-satellite links, and any one of these satellites can communicate with terminal device 710 and / or ground station 720. Figure 7 As shown, it is assumed that the service link between satellite 1 and terminal equipment 710 is in a connected state, satellite 1 and satellite 2 communicate through an inter-satellite link, and the power supply link between satellite 2 and ground station 720 is in a connected state.

[0104] In this embodiment, when the power supply link between satellite 1 and ground station 720 is interrupted, the communication mode between satellite 1 and terminal device 710 will switch from non-store-and-forward mode to store-and-forward mode. In store-and-forward mode, communication data sent by the input end is stored in the satellite network until a communication connection is established between the satellite network and the output end, at which point the communication data is sent to the output end. The input end is either terminal device 710 or ground station 720, and the output end is the other of terminal device 710 and ground station 720. Non-store-and-forward mode refers to communication modes other than store-and-forward mode, such as instant messaging, simplex communication, half-duplex communication, and full-duplex communication, etc., which are not specifically limited here.

[0105] Assuming the power supply link between satellite 1 and ground station 720 is connected, terminal device 710 can directly transmit data with ground station 720 through satellite 1.

[0106] The terminal equipment involved in this application may be a device with wireless transceiver capabilities or a chip or chip system that can be installed in the device, which allows users to access the network and is a device used to provide voice and / or data connectivity to users. The terminal equipment may also be referred to as terminal equipment, user equipment (UE), user unit (subscriber unit), terminal, mobile station (MS), or mobile terminal (MT), etc.

[0107] For example, the terminal device 710 may be a mobile phone, a tablet computer, or a computer with wireless transceiver capabilities. Terminal equipment can also be user stations, mobile stations, remote stations, remote terminal equipment, mobile terminal equipment, user terminal equipment, wireless communication equipment, user agents, user devices, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices, processing devices connected to wireless modems, in-vehicle equipment, wearable devices, terminal equipment in the Internet of Things (IoT), home appliances, virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals in industrial control, wireless terminals in autonomous driving, wireless terminals in telemedicine, wireless terminals in smart grids, wireless terminals in smart cities, wireless terminals in smart homes, vehicles with vehicle-to-vehicle (V2V) communication capabilities, intelligent connected vehicles, and unmanned aerial vehicles (UAVs). Unrestricted access is allowed for drones with U2U (to-UAV, U2U) communication capabilities, terminal devices in future networks, terminal devices in future evolved public land mobile networks (PLMNs), Wi-Fi stations (STAs), or terminal nodes (T-nodes) in satellite navigation systems. It is understood that the terminal device and the mobile user can be completely independent. All user-related information can be stored in a subscriber identity module (SIM) card, which can be used on the terminal device. The terminal device can interact with network-side devices by transmitting and / or receiving signals over the air interface.

[0108] In this embodiment, the ground station 720 is a ground-based communication device. The ground station 720 can be used to communicate with the satellite network. The ground station 720 can be a base station, server, or other network communication device capable of communicating with satellite relay equipment. The ground station 720 in this embodiment can include various forms of macro base stations, micro base stations (also called small stations), relay stations, access points, etc.

[0109] The satellite communication method of this application embodiment will be described in detail below with reference to the accompanying drawings. For example, as shown... Figure 8 As shown, the above-mentioned satellite communication method can be described from three aspects in this application embodiment.

[0110] Content 1: Paging process based on the location area information of the terminal device and the ephemeris information of the satellite.

[0111] For example, Figure 9 This is a flowchart illustrating a satellite communication method provided in an embodiment of this application, as shown below. Figure 9 As shown, the method may include the following steps:

[0112] S901, the control center sends a paging request to the AMF. Correspondingly, the AMF receives the paging request from the control center.

[0113] The control center is located at the ground station. The AMF can belong to the ground station or be a network element independent of the ground station; no restrictions are made here.

[0114] In this embodiment, when the control center needs to page a terminal device, it can send the paging request to the AMF after generating the paging request. For example, the control center can generate a paging request in cases of emergency calls (such as natural disasters, medical emergencies, etc.), service notifications (such as insufficient account balance, service expiration, etc.), and normal communication (such as telephone calls, sending text messages, data transmission, etc.).

[0115] Optionally, the paging request generated by the control center may include the identification information of the paged terminal device. For example, the paging request may include any one of the following: International Mobile Equipment Identification Number (IMEI), International Mobile Subscriber Identification Number (IMSI), Global Unique Temporary Identifier (GUTI), or Mobile Equipment Identifier (MEID) of the paged terminal device.

[0116] S902, AMF obtains the location area information of the terminal device.

[0117] Among them, the location area information of the terminal device is used to indicate the location area of ​​the terminal device. The location area of ​​the terminal device is the location area of ​​the terminal device that is latest stored in AMF. It can be the location area determined when the terminal device first requests it, or it can be the updated location area. There is no limitation here.

[0118] Optionally, after determining the location area of ​​the terminal device, the AMF stores the location area of ​​the terminal device. The AMF can retrieve the pre-stored location area of ​​the terminal device. The process of the AMF determining the location area of ​​the terminal device is described below and will not be detailed here.

[0119] S903, the control center sends the satellite's ephemeris information to the AMF.

[0120] In this embodiment, S902 and S903 can be executed sequentially, or S903 can be executed first and then S902, or S902 and S903 can be executed simultaneously. In this embodiment, the execution order of S902 and S903 is not limited.

[0121] Optionally, S904,AMF determines the first satellite based on the location area information of the terminal device and the ephemeris information of the satellite.

[0122] The first satellite refers to the satellite whose beam covers the terminal equipment. There can be one or more first satellites.

[0123] In this embodiment of the application, the AMF can determine the first satellite covering the terminal device and the target beam covering the terminal device in the beam corresponding to the first satellite based on the location area information of the terminal device and the ephemeris information of the satellite.

[0124] For example, after receiving the satellite ephemeris information from the control center, the AMF determines the satellite's latitude and longitude coordinates based on the ephemeris information. Then, the AMF stores the satellite's latitude and longitude coordinates. Subsequently, the AMF can retrieve the pre-stored satellite latitude and longitude coordinates. The AMF can determine the satellite's elevation angle based on the satellite's latitude and longitude coordinates and the latitude and longitude coordinates corresponding to the center point of the location area (e.g., the latitude and longitude coordinates of the terminal device). After calculating the satellite's elevation angle, the AMF identifies satellites with elevation angles greater than an elevation angle threshold as the first satellite.

[0125] For example, if the location area of ​​the terminal device is circular, the center point of the location area is the center of the circle. If the location area of ​​the terminal device is elliptical, the center point of the location area is the center of symmetry of the ellipse. If the location area of ​​the terminal device is a regular hexagon, the center point of the location area is the point inside the regular hexagon that is equidistant from all vertices of the regular hexagon and equidistant from all sides.

[0126] The satellite's elevation angle refers to the angle between the line of sight from the terminal device to the satellite and the horizon where the terminal device is located. The satellite's elevation angle describes its position above the terminal device at a given moment; for example, an elevation angle of 90 degrees indicates that the satellite is directly above the terminal device. For instance, Figure 10 An example diagram illustrating the elevation angle of a satellite provided in an embodiment of this application. For example... Figure 10 As shown, at a given moment, the angle between the line of sight from the terminal device at point A on Earth to the satellite and the horizon at point A is the elevation angle of the satellite.

[0127] Optionally, the AMF can determine the satellite's elevation angle based on the satellite's latitude and longitude coordinates and the terminal device's latitude and longitude coordinates. The AMF can first convert the satellite's latitude and longitude coordinates and the terminal device's latitude and longitude coordinates into radians. Then, the AMF can calculate the satellite's elevation angle using the following formulas (1) and (2).

[0128] cos(θ)=sin(φ SAT )·cos(φ GND )·cos(h SAT )+cos(φ SAT )·sin(φ GND ) formula (1);

[0129] θ=arccos(cos(θ)) formula (2);

[0130] Where θ represents the satellite's elevation angle, φ STA Indicates the latitude of the satellite, φ GND h represents the latitude of the terminal device. SAT This indicates the satellite's altitude relative to the Earth's surface.

[0131] It should be understood that the above-described method for determining the elevation angle of a satellite using AMF is only an example. The elevation angle can also be calculated from angle information such as the subtended angle and / or central angle of the satellite. The method for determining the elevation angle of a satellite using AMF in this application embodiment is not limited.

[0132] Furthermore, the AMF acquires the beam coverage map of the first satellite and determines the beams covering the location area of ​​the terminal equipment based on the beam coverage map. The beam coverage map is a graphical representation of the coverage area formed by the satellite beams on the Earth's surface. The beam coverage map includes the geographical area covered by the beams.

[0133] It should be understood that the ephemeris information obtained by the AMF can be from multiple satellites. After calculating the ephemeris information of multiple satellites, the AMF can determine that the first satellite with an elevation angle greater than the elevation angle threshold can be one or more. Furthermore, as the terminal device moves, its current location changes, causing its location area to be updated. Consequently, the first satellite and beam information determined by the AMF based on the terminal device's location area information and the satellite ephemeris information are not fixed, which helps increase the probability that the first satellite successfully pagees the terminal device.

[0134] S905, the AMF sends a second paging message to the first satellite. Correspondingly, the first satellite receives the second paging message sent by the AMF.

[0135] The second paging message is used to instruct the terminal equipment to establish a communication connection with the first satellite. This second paging message carries the identification information of the first satellite and the identification information of the beam covering the location area of ​​the terminal equipment. The identification information of the first satellite is used to uniquely identify the first satellite. This identification information can be an international satellite identifier, satellite name, or orbital parameters, etc. The beam identification information is used to uniquely identify and control a specific beam on the satellite. This beam identification information can be a beam identification code (ID), beam number, or beam name, etc.

[0136] S906, the first satellite sends the first paging message.

[0137] In this embodiment, after receiving the first paging message from the AMF, the first satellite transmits a second paging message within the location area using a beam covering the location area of ​​the terminal device. The first paging message carries the identification information of the terminal device.

[0138] Optionally, when the first satellite sends the first paging message, a second timer can be started. During the operation of the second timer, the first satellite continuously sends the first paging message within the location area of ​​the terminal device until the first satellite receives a connection establishment request from the terminal device and stops sending the first paging message. This avoids the situation where the first satellite sends the first paging message for a long time, resulting in large signaling overhead.

[0139] If the first satellite does not receive a connection establishment request from the terminal device when the second timer expires, it restarts the second timer and sends the first paging message again during its operation. Thus, the first satellite paging the terminal device multiple times, each time during the second timer's operation, not only avoids excessive paging signaling overhead but also increases the probability of successfully paging the terminal device.

[0140] In the case of multiple first satellites, the location area of ​​the terminal device may be within the coverage area of ​​the beams of multiple first satellites, and the multiple first satellites can use multiple beams to send the first paging message respectively.

[0141] In the case of a single first satellite, the location area of ​​the terminal device may be within the coverage area of ​​multiple beams of that first satellite, and the first satellite may use multiple beams to send the first paging message respectively.

[0142] In one implementation, the first satellite can simultaneously transmit the first paging message using multiple target beams. Each paging message transmitted by the first satellite through a target beam carries the identification information of the terminal device. For example, if there are five target beams covering the location area of ​​the terminal device, the first satellite can simultaneously transmit paging messages carrying the terminal device's identification information through these five target beams. Therefore, by using multiple target beams to transmit the first paging message in parallel, the efficiency of paging terminal devices is improved.

[0143] In another implementation, the first satellite can sequentially send first paging messages using different target beams in a preset order until it receives a connection establishment request from the terminal device or multiple target beams have sent first paging messages. Thus, the first satellite uses multiple target beams to sequentially send first paging messages to page the terminal device, and the subsequent paging process can be stopped once the terminal device is successfully paged, reducing paging overhead.

[0144] Optionally, when the first satellite transmits the first paging message using the first-ordered target beam, it starts a second timer. During the operation of the second timer, the first satellite continuously transmits the first paging message using the first-ordered target beam until the first satellite receives a connection establishment request from the terminal device or the second timer expires. If the first satellite does not receive the connection establishment request from the terminal device when the second timer expires, it may transmit the first paging message using the second-ordered target beam. When the first satellite transmits the first paging message using the second-ordered target beam, it also starts a second timer. During the operation of the second timer, the first satellite continuously transmits the first paging message using the second-ordered target beam until the first satellite receives a connection establishment request from the terminal device or the second timer expires. Similarly, if the first satellite transmits the first paging message sequentially using multiple target beams covering the location area of ​​the terminal device and does not receive a connection establishment request from the terminal device, the first satellite stops transmitting the first paging message.

[0145] For example, the first satellite can sequentially send the first paging message according to the coverage range of multiple target beams within the location area, from largest to smallest. For instance, if the target beams covering the location area of ​​the terminal device are beam 1, beam 2, and beam 3, and their coverage ranges within the location area are, from largest to smallest, beam 2, beam 1, and beam 3, the first satellite can send the first paging message in the order of beam 2, beam 1, and beam 3. It should be understood that if the first satellite sends the first paging message using beam 1, and then receives a connection establishment request from the terminal device, the first satellite determines that it has successfully paged the terminal device, and the first satellite does not need to send the first paging message using beams 1 and 3. Therefore, by prioritizing the use of target beams with the largest coverage range within the location area to send the first paging message, the first satellite increases the probability of successfully paged the terminal device and reduces the satellite's paging overhead.

[0146] For another example, the first satellite can send the first paging message in descending order of the number of terminal devices covered by the target beam in the location area. For instance, if the target beams are beam 1, beam 2, and beam 3, and the number of terminal devices covered by these three beams in the location area, in descending order, is beam 3, beam 1, and beam 2, the first satellite can send the first paging message in the order of beam 3, beam 1, and beam 2. It should be understood that if the first satellite sends the first paging message using beam 3 and then receives a connection establishment request from a terminal device, the first satellite has successfully paged the terminal device, and does not need to use beams 1 and 2 to send the first paging message. Therefore, by prioritizing the target beam with the largest number of terminal devices within its coverage area, the first satellite increases the probability of successfully paged the terminal device and reduces the satellite's paging overhead.

[0147] S907, the terminal device sends a connection establishment request to the first satellite.

[0148] In this embodiment, the terminal device listens for a paging channel within the location area. Once the terminal device receives a first paging message, it sends a connection establishment request to the first satellite. For example, this connection establishment request can be a radio resource control (RRC) connection establishment request. After receiving the RRC connection establishment request from the terminal device, the first satellite responds by sending an RRC connection establishment message to the terminal device. The RRC connection establishment message includes RRC connection configuration information, such as system information, security configuration, and cell configuration. After successfully establishing an RRC connection with the first satellite, the terminal device can communicate with the first satellite.

[0149] The satellite communication method provided in this application involves the AMF (Advanced Position Controller) determining the first satellite and its beam information for paging the terminal device based on the latest location area of ​​the terminal device and the satellite's ephemeris information. After the AMF sends a second paging message to the first satellite, the first satellite transmits the first paging message through the target beam covering the terminal device. Because the terminal device's location changes during movement, its location area is updated. Consequently, the AMF's determination of the first satellite and target beam for paging the terminal device also changes based on the latest location area of ​​the terminal device and the satellite's ephemeris information. This method, by determining the first satellite and target beam for paging the terminal device based on the latest location area of ​​the terminal device and the satellite's ephemeris information, and then having the first satellite transmit the first paging message through the target beam, increases the probability of successfully paging the terminal device and reduces paging overhead to some extent.

[0150] Content 2: Procedure for determining the location area of ​​terminal equipment.

[0151] The following is about Figure 9 The process by which the AMF determines the location area of ​​the terminal device in the method shown will be described in detail. The location area of ​​the terminal device can be the initial location area corresponding to the location when the terminal device is powered on, or the updated location area corresponding to the location update. The following section will combine... Figures 11 to 13 The process of determining the initial location area and the updated location area of ​​the terminal device is described in detail.

[0152] For example, Figure 11 This application provides a schematic diagram of a signaling interaction process for determining the location area of ​​a terminal device, as illustrated in an embodiment of the present application. Figure 11 As shown, the method may include the following steps:

[0153] S1101, the terminal device sends a registration request to the second satellite. Correspondingly, the second satellite receives the registration request from the terminal device.

[0154] The registration request is used to request the determination of the location area of ​​the terminal device. The registration request can be a RegistrationRequest signaling message.

[0155] Optionally, the registration request may include initial position or speed information of the terminal device, which is used to determine the location area of ​​the terminal device. Furthermore, the registration request may also carry time information indicating when the terminal device sent the registration request.

[0156] For details on how to determine the location area of ​​the terminal device based on the initial position or velocity information, please refer to the following detailed introduction, which will not be described in detail here.

[0157] After the terminal device is powered on and a communication link is established between the terminal device and the second satellite, the terminal device can send a registration request to the second satellite via the wireless access network. It should be understood that this second satellite is the one currently providing services to the terminal device. That is, after the terminal device sends the registration request, the second satellite receives the request and verifies its validity. Once the second satellite authenticates the device, it authorizes the terminal device to access the network and allocates necessary resources. The second satellite then sends a registration confirmation message to the terminal device. After receiving the registration confirmation message and configuring it, the terminal device can use the services provided by the second satellite. The second satellite and the aforementioned first satellite can be the same satellite or different satellites; this is not limited here.

[0158] S1102, the second satellite sends a registration request to the AMF. Correspondingly, the AMF receives the registration request sent by the second satellite.

[0159] In this embodiment, after receiving the registration request, the second satellite forwards the registration request to the AMF. Here, the second satellite only forwards the registration request and does not perform any substantive data processing on it.

[0160] Optionally, after receiving the registration request, the second satellite forwards the initial position or velocity information and time information of the terminal device to the AMF, and stores the time information carried in the registration request for use when updating the location area of ​​the terminal device later. This will not be elaborated here.

[0161] The second satellite can use the timestamp of the registration request sent by the terminal device as the time information for sending the registration request. Considering the latency in information propagation on the satellite (e.g., tens of milliseconds), and given the significant difference between the time the terminal device sends the registration request and the time the second satellite receives it, the on-board transmission latency is generally considered negligible. Therefore, using the timestamp of the registration request sent by the terminal device as the time information for sending the registration request eliminates the need for the terminal device to send additional time information. Similarly, in subsequent embodiments, the timestamp of the registration update request sent by the terminal device will be used as the update time information for the terminal device.

[0162] S1103, AMF determines the location area of ​​the terminal device based on the initial position and / or velocity information.

[0163] Optionally, the registration request received by the AMF includes a request type identifier, which indicates the type of request message. For example, the request type identifier indicates whether the registration request received by the AMF is an initial request, a periodic update request, or another type of request. For instance, the "Registration Request" includes a "registrationType" field, which can indicate whether it is an initial request, a periodic update request, or another type of request.

[0164] The AMF determines that the registration request received is the first request message sent by the terminal device. The AMF can determine the location area of ​​the terminal device based on the initial position and / or speed information of the terminal device.

[0165] For example, suppose the location area of ​​the terminal device is circular, and the location area includes a circular region with the initial position of the terminal device as the center and the radius of the location area as the radius. For example, such as Figure 12 As shown, assume that the AMF determines that the terminal device is initially located at point A, and the radius of the location area is R1. The location area of ​​the terminal device is a circular area with A as the center and the radius of the location area R1 as the radius.

[0166] Taking the location area of ​​a terminal device as a circular region as an example, this section introduces how AMF determines the location area of ​​a terminal device.

[0167] In one implementation, the AMF (Advanced Location Function) can determine the location area radius based on the beam size of the coverage terminal equipment corresponding to the second satellite. When the AMF determines that the beam is wide and the coverage area of ​​a single cell is large, the AMF can set a larger location area radius. When the AMF determines that the beam is narrow and the coverage area of ​​a single cell is small, the AMF can set a smaller location area radius. That is, the location area of ​​the terminal equipment is a circular area centered on the initial position and with the set location area radius as the radius.

[0168] In another implementation, the registration request received by the AMF includes the speed information of the terminal device. In this case, the AMF can determine the location area radius based on the terminal device's speed information. When the AMF determines that the terminal device's moving speed is high, the AMF can set a larger location area radius. When the AMF determines that the terminal device's moving speed is low, the AMF can set a smaller location area radius. It should be understood that a larger location area radius corresponding to the terminal device can avoid the terminal device frequently crossing the location area boundary, reducing the number of times the terminal device's location information is updated and the signaling overhead.

[0169] It should be understood that the method described above for the AMF to determine the location radius of the terminal device based on beam size or terminal device speed information is merely an example. The AMF can also determine the location radius of the terminal device using other methods, and the comparison in this application embodiment is not limited. For example, the AMF can also determine the location radius of the terminal device based on geography and user density.

[0170] S1104, the AMF sends a registration response to the second satellite. Correspondingly, the second satellite receives the registration response from the AMF.

[0171] The registration response is used to indicate the location area of ​​the terminal device. Optionally, the registration response may include the location area of ​​the terminal device, such as a location region code corresponding to the location area.

[0172] Furthermore, the AMF can store the location area of ​​the terminal device, for example, the AMF stores the location area of ​​the terminal device in the UE context of the terminal device.

[0173] S1105, the second satellite sends a registration response to the terminal device. Correspondingly, the terminal device receives the registration response sent by the second satellite.

[0174] In this embodiment, after the AMF determines the location area of ​​the terminal device, it sends a registration response indicating the location area of ​​the terminal device to the second satellite. The second satellite then forwards the registration response to the terminal device, allowing the terminal device to determine its location area based on the information carried in the registration response. Furthermore, the terminal device can store the received location area.

[0175] Content 3: Location area update process for terminal devices.

[0176] In this embodiment, during communication between the terminal device and the satellite, the terminal device can detect its current location in real time or periodically to determine whether it is within a location area. If the terminal device's current location is not within a location area, the terminal device requests an update to its location area. Alternatively, after receiving a registration response from the second satellite, the terminal device starts a first timer. When the first timer expires, the terminal device requests an update to its location area. The duration of the first timer is the mandatory update time for the location area.

[0177] The following is combined with Figure 13 The process of a terminal device requesting an update to its location area is described in detail.

[0178] Figure 13 This application provides a schematic diagram of a signaling interaction process for updating the location area of ​​a terminal device, as illustrated in an embodiment of the present application. Figure 13 As shown, the method may include the following steps:

[0179] S1301, the terminal device sends a registration update request to the second satellite. Correspondingly, the second satellite receives the registration update request from the terminal device.

[0180] The registration update request is used to request an update to the location area of ​​the terminal device.

[0181] S1302, the second satellite sends a registration update request to the AMF. Correspondingly, the AMF receives the registration update request from the second satellite.

[0182] Optionally, the registration update request may include the terminal device's current location and update time information. The current location information and update time information are used by the AMF to determine the updated location area. The update time information refers to the timestamp at which the terminal device sent the registration update request.

[0183] Optionally, if the terminal device has the ability to detect its own speed, the registration update request may also include the terminal device's speed information and update time information, which are used to determine the updated location area. This embodiment does not provide a detailed description of the specific process by which the AMF determines the updated location area based on the terminal device's speed information and update time information.

[0184] S1303, AMF determines the updated location area based on the current location and update time information.

[0185] Optionally, the AMF receives the registration update request from the second satellite, which includes the terminal device's current location and update time information. If the AMF determines that the received registration update request is the terminal device's first request to update its location area, the AMF determines the time difference between the update time information and the time when the terminal device first requested to determine its location area (i.e., the time information for sending the registration request). For example, assuming the terminal device first requests to determine its location area at time T1, and the terminal device sends the registration update request at time T2 (i.e., the update time information is T2), the AMF determines the time difference to be T2-T1.

[0186] If the AMF determines that the received registration update request is not the first message sent by the terminal device requesting a location area update, then the AMF determines the time difference between the update time information and the time when the terminal device last requested a location area update. For example, assuming the terminal device sends a registration update request at time T3 and then sends another registration update request at time T4, the AMF determines the time difference to be T4-T3.

[0187] Optionally, after the AMF determines the time difference, the AMF can determine the updated location area radius based on the relationship between the time difference and a preset duration. In one case, if the time difference is less than or equal to the preset duration, the updated location area radius is the product of the previously requested location area radius and a first ratio. The first ratio is the ratio of the preset duration to the time difference. In another case, if the time difference is greater than the preset duration, the updated location area radius is the previously requested location area radius.

[0188] For example, the AMF can use the following formula (3) to determine the updated location area radius.

[0189]

[0190] In the above formula, R i Ri represents the radius of the location region after the i-th request update, R0 represents the radius of the location region determined in the first request, and ΔT represents the radius of the location region determined in the first request. i ΔT0 represents the time difference between the i-th update and the (i-1)-th update, ΔT0 represents the forced update time of the location region, αΔT0 represents the preset duration, α is the system's tolerable update parameter, and α represents the ratio of the minimum update time with the location region radius unchanged to the forced update time.

[0191] From the above formula, it can be seen that when ΔT i ≤αΔT means that when the time difference between the current request for a location area update and the previous request for a location area determination is less than a preset time, it indicates that the terminal device's movement speed is relatively high, while the radius of the current location area is relatively small. In this case, AMF can increase the time the terminal device spends within the location area by increasing the radius of the terminal device's location area. This avoids the terminal device frequently moving at the boundary of the location area, frequently requesting location information updates, and thus avoiding high signaling overhead.

[0192] When ΔT i >αΔT0, meaning the time difference between the current request for location area update and the previous request for location area determination is less than a preset time, indicates that the terminal device's location is within the designated location area in both requests. In this case, the AMF does not need to adjust the terminal device's location area radius. That is, the radius of the location area determined in the i-th request is the same as the radius of the location area determined in the (i-1)-th request.

[0193] For example, such as Figure 12As shown, assuming the initial position of the terminal device corresponds to point A, the radius of the location area determined by the AMF is R1. When the terminal device moves from point A to point B, its current position is not within the location area, and the terminal device requests an update to the location area. Assuming that after receiving the registration update request, the AMF determines that the time difference between the terminal device sending the registration update request and the last time it sent the registration update request is less than a preset duration, then the location area radius determined by the AMF to be R1 is relatively small. The AMF can increase the location area radius, for example, by determining the location area radius to be R2 (R2 > R1). In this case, the terminal device's location area corresponds to a circular region with the terminal device's current position B as the center and R2 as the radius.

[0194] It should be understood that the above process for determining the updated location area is based on the example of a circular location area on the terminal device. Of course, the location area of ​​the terminal device can also be other shapes, and this is not limited here.

[0195] S1304, the AMF sends a registration update response to the second satellite. Correspondingly, the base station of the second satellite receives the registration update response sent by the AMF.

[0196] S1305, the second satellite sends a registration update response to the terminal device. Correspondingly, the terminal device receives the registration update response sent by the base station of the second satellite.

[0197] In this embodiment, after the AMF determines the updated location area, it sends a registration update response indicating the updated location area to the second satellite, and then forwards the registration update response to the terminal device through the second satellite. This allows the terminal device to determine its updated location area based on the information carried in the registration update response after receiving it.

[0198] In this embodiment, the AMF can update the location area of ​​the terminal device based on the current location of the terminal device, thus avoiding the situation where the location area radius is small in the scenario where the location area of ​​the terminal device is fixed, which leads to frequent updates of the location information of the terminal device and a large signaling overhead.

[0199] In scenarios with a large number of terminal devices, designing a separate location area for each terminal device could increase location area management overhead. Therefore, AMF (Approx. Location Function) can cluster the location areas of terminal devices into grouped location areas. Specifically, AMF determines a group of location areas with a large radius, which includes the location areas corresponding to multiple terminal devices. This solves the problem of frequent location area updates by terminal devices and also reduces the overhead of managing the location areas of multiple terminal devices to some extent.

[0200] The foregoing mainly describes the solutions provided by the embodiments of this application from the perspective of interaction between various devices. It is understood that each device, such as a terminal device or a first satellite, includes corresponding hardware structures and / or software modules to perform the aforementioned functions. Those skilled in the art should readily recognize that, based on the algorithm steps of the examples described in conjunction with the embodiments disclosed herein, 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 and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0201] This application embodiment can group terminal devices, first satellites, etc., into functional modules according to the above method example. For example, each functional group can correspond to a functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. The grouping of modules in this application embodiment is illustrative and only represents one logical functional grouping. In actual implementation, there may be other grouping methods.

[0202] Figure 14 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application, such as... Figure 14 As shown, the communication device 1400 may include one or more processors 1401, memory 1402 and communication interface 1403.

[0203] The memory 1402, communication interface 1403, and processor 1401 are coupled together. For example, the memory 1402, communication interface 1403, and processor 1401 can be coupled together via bus 1404.

[0204] Processor 1401 may be the control center of a communication device, and may be a processor or controller. For example, processor 1401 may be a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It may implement or execute various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of embodiments of this application. The processor may also be a combination that implements computing functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0205] The communication interface 1403 is used to communicate with other devices or communication networks, such as Ethernet, RAN, wireless local area networks (WLAN), etc. The communication interface 1403 can also be a transceiver circuit located within the processor 1401, used to implement the processor's signal input and signal output.

[0206] Memory 1402 can be a device with storage function. For example, it can be read-only memory (ROM) or other types of static storage devices capable of storing static information and instructions; random access memory (RAM) or other types of dynamic storage devices capable of storing information and instructions; electrically erasable programmable read-only memory (EEPROM); compact disc read-only memory (CD-ROM) or other optical disc storage; optical disc storage (including compressed optical discs, laser discs, optical discs, digital versatile optical discs, Blu-ray discs, etc.); magnetic disk storage media or other magnetic storage devices; or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto. Memory can exist independently and be connected to the processor via bus 1404. Memory can also be integrated with the processor.

[0207] The memory 1402 is also used to store computer execution instructions for implementing the scheme of this application, and the execution is controlled by the processor 1401. The processor 1401 is used to execute the computer execution instructions stored in the memory 1402, thereby implementing the method provided in the embodiments of this application.

[0208] Alternatively, in this embodiment, the processor 1401 may execute the processing-related functions of the method provided in the following embodiments of this application, and the communication interface 1403 may be responsible for communicating with other devices or communication networks. This embodiment does not specifically limit this.

[0209] The computer execution instructions in the embodiments of this application may also be referred to as application code, and the embodiments of this application do not specifically limit this.

[0210] Bus 1404 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The aforementioned bus 1404 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 14 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0211] In some embodiments, processor 1401 may include one or more CPUs.

[0212] In some embodiments, the communication device 1400 may include multiple processors. Each of these processors may be a single-core processor or a multi-core processor. The processors may include, but are not limited to, at least one of the following: CPU, microprocessor, DSP, microcontroller unit (MCU), or artificial intelligence processor, and other computing devices that run software. Each computing device may include one or more cores for executing software instructions to perform calculations or processing.

[0213] This application provides a communication system. Figure 15 This is a schematic diagram of a communication system provided in an embodiment of this application. Figure 15 As shown, the communication system 1500 may include a terminal device 1501, a first satellite 1502, a second satellite 1503, and an AMF 1504.

[0214] The terminal device 1501 is used to receive a paging message from the first satellite 1502 and, in response to the paging message, send a connection establishment request to the first satellite 1502. The first satellite is determined based on the location area information of the terminal device and the ephemeris information of the satellite, and the first satellite is at least one of the satellites. The connection establishment request is used to request the establishment of a communication connection with the first satellite.

[0215] Terminal device 1501 is also configured to receive a registration response from second satellite 1503 after sending a registration request to second satellite 1503; wherein, the registration request is used to request the determination of the location area of ​​terminal device 1501. Second satellite 1503 may be the same as or different from first satellite 1502; the registration response is used to indicate the location area of ​​terminal device 1501.

[0216] The terminal device 1501 is also used to send a registration update request to the second satellite 1503 when the current location of the terminal device 1501 is not within the location area or when the first timer expires; wherein, the registration update request is used to request an update of the location area of ​​the terminal device; the first timer is started when the terminal device receives a registration response.

[0217] After receiving a paging request from the control center, AMF1504 responds to the paging request by sending a second paging message to the first satellite 1502 based on the location area information of the terminal device 1501 and the ephemeris information of the satellite.

[0218] The first satellite 1502 is used to receive a second paging message from the AMF and then send a first paging message; it also receives a connection establishment request sent by a terminal device; wherein the connection establishment request is used to establish a communication connection with the first satellite.

[0219] The second satellite 1503 receives a registration request from the terminal device 1501 and then sends a registration request to the AMF 1504; the registration request is used to request the determination of the location area of ​​the terminal device; after receiving a registration response from the AMF 1504, it sends a registration response to the terminal device 1501. The registration response is used to indicate the location area of ​​the terminal device.

[0220] The second satellite 1503 is also used to receive a registration update request from the terminal device 1501 and then send a registration update request to the AMF 1504; wherein the registration update request is used to request an update of the location area of ​​the terminal device. After receiving a registration update response from the AMF 1504, it sends a registration update response to the terminal device 1501; wherein the registration update response is used to indicate the updated location area.

[0221] The terminal device 1501, the first satellite 1502, the second satellite 1503, and the AMF 1504 in this application embodiment can be used to execute the satellite communication method provided in the foregoing embodiment.

[0222] This application also provides a communication device, including one or more processors and one or more memories. The one or more memories are coupled to the one or more processors, and the one or more memories are used to store computer program code, including computer instructions. When the one or more processors execute the computer instructions, the communication device performs the aforementioned method steps to implement the satellite communication method in the above embodiments.

[0223] Embodiments of this application also provide a computer-readable storage medium storing computer instructions that, when executed on a communication device, cause the communication device to perform the aforementioned method steps to implement the satellite communication method in the above embodiments.

[0224] Embodiments of this application also provide a chip system including a memory and a processor, wherein the program / instructions stored in the memory are executed by the processor to implement the satellite communication method described in the above embodiments.

[0225] It is understood that, in order to achieve the above functions, the terminal device, satellite, and ground station include the corresponding hardware structures and / or software modules for performing each function. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein, the embodiments of 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 and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this invention.

[0226] This application embodiment can divide the terminal device, satellite, and ground station into functional modules according to the above method examples. For example, each function can be divided into its own functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. The module division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0227] Through the above description of the embodiments, those skilled in the art will clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0228] In the embodiments of this application, the functional units can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0229] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, essentially, or the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as flash memory, portable hard disk, read-only memory, random access memory, magnetic disk, or optical disk.

[0230] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of protection of this application.

Claims

1. A satellite communication method, characterized in that, Applied to a terminal device, the method includes: Receive a first paging message from a first satellite; wherein the first satellite is determined based on the location area information of the terminal device and the ephemeris information of the satellite, the first satellite is at least one of the satellites, and the location area information of the terminal device is used to indicate the location area of ​​the terminal device; In response to the first paging message, a connection establishment request is sent to the first satellite; wherein the connection establishment request is used to request the establishment of a communication connection with the first satellite.

2. The method according to claim 1, characterized in that, Before receiving the first paging message from the first satellite, the method further includes: A registration request is sent to a second satellite; wherein the registration request is used to request the determination of the location area of ​​the terminal device; the second satellite is a satellite that is to provide services to the terminal device; Receive a registration response from the second satellite; wherein the registration response is used to indicate the location area of ​​the terminal device.

3. The method according to claim 2, characterized in that, The registration request includes the initial position or speed information of the terminal device, and the initial position or speed information is used to determine the location area of ​​the terminal device.

4. The method according to claim 2 or 3, characterized in that, Before receiving the first paging message from the first satellite, the method further includes: If the current location of the terminal device is not within the location area or the first timer expires, a registration update request is sent to the second satellite; wherein, the registration update request is used to request an update of the location area of ​​the terminal device; the first timer is started when the terminal device receives a registration response; Receive a registration update response from the second satellite; wherein the registration update response is used to indicate the updated location area.

5. The method according to claim 4, characterized in that, The registration update request includes the current location and update time information of the terminal device, and the current location and update time information are used to determine the updated location area.

6. The method according to claim 5, characterized in that, The updated location area includes a circular region with the current location as the center and the radius of the updated location area as the radius; If the time difference is less than or equal to a preset duration, the updated location area radius is the product of the previously requested location area radius and a first ratio, where the first ratio is the ratio of the preset duration to the time difference. or, If the time difference is greater than the preset duration, the updated location area radius is the location area radius of the terminal device determined in the previous request; Wherein, the time difference is the time difference between the update time information and the time difference between the last request on the terminal device to determine the location area, or the time difference is the time difference between the update time information and the time difference between the first request on the terminal device to determine the location area, and the last request is the request with the shortest time interval between the registration update request and the previous request.

7. The method according to claim 4, characterized in that, The registration update request includes the speed information and update time information of the terminal device, and the speed information and update time information are used to determine the updated location area.

8. A satellite communication method, characterized in that, The method, applied to the Access and Mobility Management Function (AMF) network element, includes: Received a paging request from the control center; In response to the paging request, a second paging message is sent to the first satellite based on the location area information of the terminal device and the ephemeris information of the satellite, wherein the location area information of the terminal device is used to indicate the location area of ​​the terminal device.

9. The method according to claim 8, characterized in that, The method further includes: Receive a registration request from a second satellite; wherein the registration request is used to request the determination of the location area of ​​the terminal device; Send a registration response to the second satellite; wherein the registration response is used to indicate the location area of ​​the terminal device.

10. The method according to claim 9, characterized in that, The registration request includes the initial position or speed information of the terminal device, and the initial position or speed information is used to determine the location area of ​​the terminal device.

11. The method according to any one of claims 8-10, characterized in that, The method further includes: Receive a registration update request from a second satellite; wherein the registration update request is used to request an update of the location area of ​​the terminal device; Send a registration update response to the second satellite; wherein the registration update response is used to indicate the updated location area.

12. The method according to claim 11, characterized in that, The registration update request includes the current location and update time information of the terminal device, and the current location and update time information are used to determine the updated location area.

13. The method according to claim 12, characterized in that, The updated location area includes a circular region with the current location as the center and the radius of the updated location area as the radius; If the time difference is less than or equal to a preset duration, the updated location area radius is the product of the previously requested location area radius and a first ratio, where the first ratio is the ratio of the preset duration to the time difference. or, If the time difference is greater than the preset duration, the updated location area radius is the location area radius of the terminal device determined in the previous request; Wherein, the time difference is the time difference between the update time information and the time difference between the last request on the terminal device to determine the location area, or the time difference is the time difference between the update time information and the time difference between the first request on the terminal device to determine the location area, and the last request is the request with the shortest time interval between the registration update request and the previous request.

14. The method according to claim 11, characterized in that, The registration update request includes the speed information and update time information of the terminal device, and the speed information and update time information are used to determine the updated location area.

15. A satellite communication method, characterized in that, Applied to a first satellite, the method includes: After receiving the second paging message from the Access and Mobility Management Function (AMF) network element, the first paging message is sent. The terminal device receives a connection establishment request; wherein the connection establishment request is used to request the establishment of a communication connection with the first satellite.

16. The method according to claim 15, characterized in that, Sending the first paging message includes: Start the second timer; During the operation of the second timer, the first paging message is sent.

17. The method according to claim 16, characterized in that, The method further includes: If no connection establishment request is received from the terminal device after the second timer expires, the first paging message is sent again.

18. The method according to any one of claims 15-17, characterized in that, The first satellite corresponds to multiple target beams, and sending the first paging message includes: The first paging message is sent sequentially using the multiple target beams, according to the order of their coverage range from largest to smallest and / or the order of the number of terminal devices covered by the multiple target beams from most to least.

19. A satellite communication method, characterized in that, Applied to a second satellite, the method includes: Receive a registration request sent by a terminal device; wherein the registration request is used to request the determination of the location area of ​​the terminal device; The registration request is sent to the Access and Mobility Management Function (AMF) network element; Receive a registration response from the AMF; wherein the registration response is used to indicate the location area of ​​the terminal device; Send the registration response to the terminal device.

20. The method according to claim 19, characterized in that, The method further includes: Receive a registration update request sent by a terminal device; wherein the registration update request is used to request an update of the location area of ​​the terminal device; Send the registration update request to the AMF; Receive a registration update response from the AMF; wherein the registration update response is used to indicate the updated location area; Send the registration update response to the terminal device.

21. A communication device comprising one or more processors, a memory, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the method of any one of claims 1-7; and / or, to implement the method of any one of claims 8-14; and / or, to implement the method of any one of claims 15-18; and / or, to implement the method of claim 19 or 20.

22. A communication system, characterized in that, The system includes terminal equipment, an access and mobility management function (AMF) network element, a first satellite, and a second satellite; The terminal device is used to perform the method according to any one of claims 1-7; The AMF is used to perform the method according to any one of claims 8-14; The first satellite is used to perform the method described in any one of claims 15-18; The second satellite is used to perform the method of claim 19 or 20.

23. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When executed by a processor, the computer program / instruction implements the method of any one of claims 1-7; and / or, the method of any one of claims 8-14; and / or, the method of any one of claims 15-18; and / or, the method of claim 19 or 20.

24. A chip system comprising a memory and a processor, characterized in that, When the program / instructions stored in the memory are executed by the processor, they implement the method of any one of claims 1-7; and / or, the method of any one of claims 8-14; and / or, the method of any one of claims 15-18; and / or, the method of claim 19 or 20.

25. A computer program product, characterized in that, The computer program product includes: a computer program or instructions that, when executed on a computer, cause the computer to perform the method of any one of claims 1-7; and / or implement the method of any one of claims 8-14; and / or implement the method of any one of claims 15-18; and / or implement the method of claim 19 or 20.

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