Access node switching method and device and mobility management controller in MEO satellite

Abstract

The invention relates to the technical field of communication, in particular to an access node switching method and device and a mobility management controller in an MEO satellite. The method comprises the following steps: in response to a switching request initiated by a target LEO satellite, selecting a target access node from candidate LEO satellites and candidate ground base stations according to terminal position information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellites are LEO satellites, except the target LEO satellite, in the LEO satellites managed by the MEO satellites, and the candidate ground base station is a ground base station managed by the MEO satellites; the predicted signal strength between the target access node and the target terminal is greater than a target strength threshold; and controlling the target terminal to disconnect with the target LEO satellite, and accessing the target access node through the target access node.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to an access node switching method and device, and a mobility management controller in a MEO satellite. Background Art

[0002] As the global fifth-generation mobile communication technology (5G) network gradually matures, research on the sixth-generation mobile communication technology (6G) has begun; among them, the global seamless connection demand in 6G network technology is one of the current research hotspots.

[0003] Traditional terrestrial networks rely on infrastructure such as base stations, and have low global communication coverage, making it difficult to provide ubiquitous and seamless communication services to users in remote areas such as oceans, deserts, and valleys. The rapid development of non-terrestrial networks (NTN) has made up for this shortcoming. Satellites serve as access nodes or relay nodes to expand the communication range and integrate with terrestrial networks to create a global coverage, seamlessly connected network system, effectively overcoming geographical limitations and providing users with highly reliable, large-bandwidth seamless communication services anytime, anywhere.

[0004] NTN mainly includes Geosynchronous Earth Orbit (GEO) satellites, Medium Earth Orbit (MEO) satellites and Low Earth Orbit (LEO) satellites. Among them, LEO satellites have outstanding advantages such as low altitude, short transmission delay, and less path loss, and can provide more efficient and ubiquitous communication services for target terminals. By combining GEO, MEO and LEO satellites in NTN with ground networks, a full-range and seamless communication network can be realized, providing users with more reliable and efficient communication services.

[0005] However, due to the fast movement speed of LEO satellites and the dynamic changes in network topology, the target terminal needs to frequently switch to access the satellite. In order to ensure business continuity and uninterrupted service, switching is required during the movement of the satellite and the target terminal. Since the current mobile management functional unit is deployed in the ground network, when performing the switching operation, the access satellite needs to go through multiple hops to complete the transmission of the switching request response, resulting in a large amount of delay and signaling overhead. Summary of the invention

[0006] Based on this, it is necessary to provide an access node switching method and device and a mobility management controller in a MEO satellite that can reduce signaling overhead in order to solve the above technical problems.

[0007] In a first aspect, the present application provides an access node switching method, which is applied to a mobility management controller in a medium earth orbit MEO satellite, where the MEO satellite communicates with a geosynchronous orbit GEO satellite, and the method includes:

[0008] In response to a handover request initiated by a target LEO satellite, a target access node is selected from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellite is a LEO satellite other than the target LEO satellite among LEO satellites managed by a MEO satellite, and the candidate ground base station is a ground base station managed by a MEO satellite; and a predicted signal strength between the target access node and the target terminal is greater than a target strength threshold;

[0009] The target terminal is controlled to disconnect from the target LEO satellite and access the target access node through the target access node.

[0010] In one embodiment, selecting a target access node from candidate LEO satellites and candidate ground base stations includes:

[0011] Acquire satellite communication information of the candidate LEO satellite and base station communication information of the candidate ground base station; wherein the satellite communication information includes satellite position information and satellite communication resource information, and the base station communication information includes base station position information and base station communication resource information;

[0012] A target access node is selected from the candidate LEO satellites and the candidate ground base stations according to the terminal location information of the target terminal, the satellite communication information of the candidate LEO satellites and the base station communication information of the candidate ground base stations.

[0013] In one embodiment, selecting a target access node from the candidate LEO satellite and the candidate ground base station according to the terminal location information of the target terminal, the satellite communication information of the candidate LEO satellite, and the base station communication information of the candidate ground base station includes:

[0014] Determining whether there is a candidate LEO satellite among the candidate LEO satellites according to the terminal position information of the target terminal and the satellite communication information of the candidate LEO satellite; wherein the predicted signal strength between the candidate LEO satellite and the target terminal is greater than the target strength threshold;

[0015] If so, select the target access node from the candidate LEO satellites;

[0016] If not, the target access node is selected from the candidate ground base stations according to the terminal location information of the target terminal and the base station communication information of the ground base station.

[0017] In one embodiment, determining whether there is a candidate LEO satellite among the candidate LEO satellites according to the terminal location information of the target terminal and the satellite communication information of the candidate LEO satellites includes:

[0018] Determine whether a first LEO satellite exists among the candidate LEO satellites according to the terminal position information of the target terminal and the satellite position information of the candidate LEO satellites; wherein a communication distance between the first LEO satellite and the target terminal is less than a distance threshold, and a predicted signal strength between the first LEO satellite and the target terminal is greater than a target strength threshold;

[0019] If yes, determining whether there is a second LEO satellite that meets the communication requirements in the handover request in the first LEO satellite according to the satellite communication resource information of the first LEO satellite;

[0020] If yes, the second LEO satellite is used as a candidate LEO satellite, and it is determined that there is a candidate LEO satellite among the candidate LEO satellites.

[0021] In one embodiment, controlling a target terminal currently communicating with a target LEO satellite to disconnect from the target LEO satellite and access the target access node through the target access node includes:

[0022] In the case where the target access node is determined to be a candidate LEO satellite, a handover control message is sent to the target access node to instruct the target access node to reserve communication resources that meet the communication requirements in the handover request;

[0023] When a reservation completion response is obtained from the target access node, a switching request response is sent to the target terminal through the target LEO satellite to instruct the target terminal to disconnect from the target LEO satellite and access the target access node through the target access node.

[0024] In one of the embodiments, when a reservation completion response fed back by a target access node is obtained, a handover request response is sent to a target terminal through a target LEO satellite, including:

[0025] When a reservation completion response fed back by the target access node is obtained and it is determined that the actual signal strength between the target LEO satellite and the target terminal is less than the actual switching strength threshold, a switching request response is sent to the target terminal via the target LEO satellite.

[0026] In one embodiment, the handover request is generated by the target LEO satellite when it is determined that the actual signal strength between the target LEO satellite and the target terminal reaches a pre-handover strength threshold; the target strength threshold is greater than the pre-handover strength threshold, and the pre-handover strength threshold is greater than the actual handover strength threshold.

[0027] In one embodiment, the method further comprises:

[0028] For each candidate LEO satellite, predict satellite position information of the candidate LEO satellite according to the constellation information and ephemeris information of the candidate LEO satellite;

[0029] Satellite communication resource information of the candidate LEO satellite is determined based on the received signal strength, remaining service time and number of idle channels of the candidate LEO satellite.

[0030] In a second aspect, the present application further provides an access node switching device, which is applied to a mobility management controller in a medium earth orbit MEO satellite, and the MEO satellite communicates with a geosynchronous orbit GEO satellite, including:

[0031] A response module, configured to respond to a handover request initiated by a target LEO satellite, and select a target access node from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellite is a LEO satellite other than the target LEO satellite among LEO satellites managed by a MEO satellite, and the candidate ground base station is a ground base station managed by a MEO satellite; and a predicted signal strength between the target access node and the target terminal is greater than a target strength threshold;

[0032] The access control module is used to control the target terminal to disconnect from the target LEO satellite and access the target access node through the target access node.

[0033] In a third aspect, the present application further provides a mobility management controller in a MEO satellite, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0034] In response to a handover request initiated by a target LEO satellite, a target access node is selected from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellite is a LEO satellite other than the target LEO satellite among LEO satellites managed by a MEO satellite, and the candidate ground base station is a ground base station managed by a MEO satellite; and a predicted signal strength between the target access node and the target terminal is greater than a target strength threshold;

[0035] The target terminal is controlled to disconnect from the target LEO satellite and access the target access node through the target access node.

[0036] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the following steps are implemented:

[0037] In response to a handover request initiated by a target LEO satellite, a target access node is selected from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellite is a LEO satellite other than the target LEO satellite among LEO satellites managed by a MEO satellite, and the candidate ground base station is a ground base station managed by a MEO satellite; and a predicted signal strength between the target access node and the target terminal is greater than a target strength threshold;

[0038] The target terminal is controlled to disconnect from the target LEO satellite and access the target access node through the target access node.

[0039] In a fifth aspect, the present application further provides a computer program product, including a computer program, which implements the following steps when executed by a processor:

[0040] In response to a handover request initiated by a target LEO satellite, a target access node is selected from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellite is a LEO satellite other than the target LEO satellite among LEO satellites managed by a MEO satellite, and the candidate ground base station is a ground base station managed by a MEO satellite; and a predicted signal strength between the target access node and the target terminal is greater than a target strength threshold;

[0041] The target terminal is controlled to disconnect from the target LEO satellite and access the target access node through the target access node.

[0042] The above-mentioned access node switching method, device and mobility management controller in the MEO satellite, the present application deploys the mobility management functional unit in the MEO satellite, which can respond to the switching request initiated by the LEO satellite more quickly than the traditional ground network deployment. Since the communication distance between the MEO satellite and the LEO satellite is relatively close and is not limited by the multi-hop transmission of the ground network, the transmission delay of the switching request response can be significantly reduced. The mobility management controller in the MEO satellite can directly control the target terminal to disconnect from the target LEO satellite and access the network through the selected target access node, avoiding the additional delay caused by multi-hop transmission in the traditional method. By directly managing the switching process of the LEO satellite and the ground base station through the MEO satellite, the switching process can be simplified and unnecessary signaling interactions can be reduced. In the traditional ground network deployment method, the switching operation needs to be forwarded and processed by multiple network nodes, resulting in a large signaling overhead. The MEO satellite in this scheme can directly communicate with the target LEO satellite and the candidate access node, thereby effectively reducing the signaling overhead.

[0043] According to the terminal location information reported by the GEO satellite, the mobility management controller can intelligently select the optimal target access node from the candidate LEO satellites and ground base stations based on accurate location information. This intelligent selection method can reduce signaling waste and resource consumption caused by frequent switching and incorrect selection of access nodes. When selecting the target access node, the predicted signal strength between the target terminal and the target terminal is taken into account to ensure that the selected access node can provide stable communication services. This selection method based on predicted signal strength can reduce communication interruptions and reconnection caused by unstable signals, further improving business continuity. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 An application environment diagram of an access node switching method in an embodiment;

[0046] Figure 2 A schematic diagram of a flow chart of an access node switching method in an embodiment;

[0047] Figure 3 A schematic diagram of a flow chart of the steps of selecting a target access node from candidate LEO satellites and candidate ground base stations in one embodiment;

[0048] Figure 4 Another is a flow chart of the step of selecting a target access node from candidate LEO satellites and candidate ground base stations in an embodiment;

[0049] Figure 5 A schematic diagram of a flow chart of a step of determining whether there is a candidate LEO satellite among candidate LEO satellites in one embodiment;

[0050] Figure 6 A schematic diagram of a flow chart of steps of accessing a target access node through a target access node in an embodiment;

[0051] Figure 7 It is a schematic diagram of the interaction of inter-satellite handover corresponding to the access node handover method in another embodiment;

[0052] Figure 8 It is a schematic diagram of the interaction of satellite-to-ground switching corresponding to the access node switching method in another embodiment;

[0053] Fig. 9 is a structural block diagram of an access node switching device in an embodiment;

[0054] Fig.10 FIG. 4 is a diagram showing the internal structure of a mobility management controller in a MEO satellite in one embodiment. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0056] Space-ground collaboration refers to the organic combination of ground networks (such as ground base stations, ground core networks, etc.) and space networks (such as satellite networks in different orbits, including LEO satellites, MEO satellites, GEO satellites, etc.) when building and operating communication networks. Space-ground collaboration can give full play to the respective advantages of ground networks and space networks and achieve complementary advantages. The ground network provides stable and high-speed communication services, while the space network has a wide coverage and can make up for the coverage blind spots of the ground network. In remote areas, oceans, deserts and other places where ground networks are difficult to cover, space-ground collaboration technology can provide users with seamless, efficient and reliable communication services.

[0057] Mobility management refers to the use of a series of technologies and strategies in communication networks to ensure that users can maintain communication continuity, stability and efficiency during mobility, based on the mobility characteristics of users or terminal devices. Mobility management technology can track and predict user location information in real time, and when users switch from one access node to another, timely adjust network resources, update data routing, and seamlessly switch connections.

[0058] Identity mapping is a mechanism that establishes a corresponding relationship between the identity of a user or device (such as user ID, device serial number, etc.) and the location identifier in the network (such as IP address, satellite orbit position, etc.) in a network environment, especially in a complex architecture such as a space-ground integrated network. Through this mapping relationship, the network can accurately identify the user's identity and route data to the correct location no matter where the user is. This is crucial for achieving communication and mobility management between users in different network nodes. In a space-ground integrated network, the identity mapping mechanism can ensure smooth communication between ground users and space users (such as satellite users). When a user moves from one network node to another, the identity mapping mechanism can quickly update the user's network location information to ensure the continuity of communication.

[0059] For example, assume that there is an integrated space-ground network, which includes a ground network and a satellite network. Ground users access the network through ground base stations, while satellite users access the network through satellites. The situation of ground users: Identity identification: User A, user ID is 12345. Location identification: User A is currently connected to ground base station B, and the IP address of base station B is 192.168.1.1. Identification mapping: The network will establish a mapping relationship between user ID 12345 and IP address 192.168.1.1. When other users want to communicate with user A, the network will find user A's IP address through identification mapping based on user A's user ID, and thus route the data to the location of user A.

[0060] Satellite user situation: Identity: User C, device serial number is XYZ123. Location: User C currently accesses the network through satellite D, and the orbital position of satellite D is a specific position in LEO (low earth orbit). Identity mapping: The network will establish a mapping relationship between the device serial number XYZ123 and the orbital position of satellite D. When other users want to communicate with user C, the network will find the orbital position of satellite D where user C is located based on user C's device serial number through identity mapping, and then route the data to the location of user C.

[0061] User movement: Assume that user A moves from ground base station B to ground base station E. The network will quickly update the location identifier of user A and establish a mapping relationship between user ID 12345 and the new IP address (IP address of base station E). In this way, even if user A moves, other users can still communicate with user A smoothly because the network will find the new location of user A based on the identifier mapping.

[0062] The above-mentioned identity mapping can be realized through the identity management server (Infinite Development Magic Server, IDMS). In traditional technology, the IDMS is deployed on the ground network. When the low-orbit satellite (LEO) moves frequently, the mobile node (MN) needs to register and update the mapping relationship with the ground IDMS when switching from one access satellite node to another.

[0063] However, due to the long signal transmission distance and large propagation delay, the switching delay increases, affecting the continuity and real-time performance of communication services. In addition, each mobile switching of the MN involves frequent signaling interactions with the ground IDMS, such as registration, updating mapping relationships, etc. A large amount of signaling is transmitted between the satellite and the ground, occupying precious communication bandwidth resources, increasing signaling overhead, and reducing network efficiency.

[0064] In order to solve the above technical problems, the access node switching method provided in the embodiment of the present application can be applied to Figure 1 The application environment diagram shown in FIG. 1 shows a system architecture of a space-ground collaborative mobility management mechanism based on identity mapping, which aims to solve the problem of discontinuous user services, large switching handover delay and signaling loss caused by the fast movement of LEO satellites in space-based networks and the binding of user identities and locations. The system architecture of the space-ground collaborative mobility management mechanism based on identity mapping includes a ground segment and a satellite segment, wherein the ground segment includes multiple access target terminals and a ground network, and the satellite segment includes a LEO satellite layer, a MEO layer and a GEO layer. Space-ground collaborative mobility management based on identity mapping can be divided into inter-satellite switching and satellite-ground switching. When the switching is triggered, based on the terminal status of the target terminal and the state perception data of the candidate LEO satellites in the LEO satellite layer, the optimal satellite / ground base station is selected for switching, and the mobility management server in the MEO satellite layer and the ground network is used to complete the unbinding and binding of the identity mapping, and finally the mobility management of multiple access target terminals is completed to ensure the continuity of user services. LEO satellites and base stations serve as access nodes for target terminals, allowing target terminals to adopt multiple access methods to select the optimal access node for communication services. In addition, the LEO satellite network also undertakes data storage and forwarding functions. Each MEO satellite is deployed with the same mobility management controller as the ground network, which is responsible for the identification binding and switching management of LEO satellites and multiple access target terminals within its coverage area. Similarly, the ground network mobility management server is responsible for the identification binding and switching management of base stations and multiple access target terminals. When a satellite-to-ground switch occurs, the MEO satellite exchanges signaling with the ground network mobility management controller through the satellite ground station to complete the switching execution process.

[0065] In an exemplary embodiment, Figure 2As shown, a method for switching access nodes is provided, and the method is applied to Figure 1 Taking any MEO satellite in the MEO layer as an example, the MEO satellite communicates with a geosynchronous orbit GEO satellite, and the access node switching method includes:

[0066] S201, in response to a handover request initiated by a target LEO satellite, selecting a target access node from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite.

[0067] Optional, Figure 1 All network entities in the space-ground collaborative mobility management system architecture have identities that identify identity information, including the target terminal's identity UID, the LEO satellite's identity LID, the MEO satellite's identity MID, the GEO satellite's identity GID, the ground base station's identity BID, and the ground network mobility management controller's identity GMID.

[0068] It can be understood that each MEO satellite in the MEO layer is used to manage the LEO satellites and ground base stations within its own coverage area. It is assumed that the LEO satellites managed by the MEO satellite in this embodiment include target LEO satellites and candidate LEO satellites. The candidate LEO satellites are LEO satellites other than the target LEO satellites among the LEO satellites managed by the MEO satellite; the candidate ground base stations are ground base stations managed by the MEO satellite.

[0069] Assume that in the initial stage, the user terminal currently communicating with the target LEO satellite is the target terminal, and the target LEO satellite provides access services for multiple access target terminals. At this time, the user UID is bound one-to-one with the target LEO satellite LID and stored in the MEO satellite identification mapping management module. As the target LEO satellite moves rapidly and gradually moves away from the target terminal, the communication signal between the target terminal and the target LEO satellite will gradually weaken. When the signal strength drops to a certain threshold, a switching request is triggered. In order to ensure user service continuity, the next suitable access node needs to be allocated to the target terminal for connection.

[0070] In this case, the mobility management controller on the MEO satellite selects a target access node from candidate LEO satellites and candidate ground base stations based on the location information of the target terminal collected by the GEO satellite.

[0071] It is understandable that due to the geosynchronous nature and wide coverage of GEO satellites, they are able to provide relatively accurate location information. Accurate terminal location information provides accuracy guarantee for the selection of subsequent target access nodes.

[0072] Optionally, the mobility management controller on the MEO satellite first collects the location information of the target terminal provided by the GEO satellite, as well as the status information of the candidate LEO satellite and the status information of the candidate ground base station (such as capacity, load, signal quality, etc.). Determine which access node can provide the best communication quality and user experience. This may require consideration of multiple factors, such as the distance of the access node, signal strength, capacity limitation, load conditions, etc. Based on the comprehensive analysis, the mobility management controller makes a decision to select the most suitable access node from the candidate LEO satellite and the candidate ground base station as the target access node.

[0073] Specifically, the predicted signal strength between the target access node and the target terminal is greater than a target strength threshold.

[0074] It is understandable that signal strength is one of the important indicators for measuring communication quality. When a terminal moves from one access node to another, in order to ensure the continuity and quality of communication, it is necessary to select an access node with sufficiently strong signal strength as the target access node. In this way, the terminal can maintain a stable communication connection after switching or reconnecting. Due to the variability and complexity of the communication environment, there may be certain challenges in directly measuring the signal strength between the target access node and the target terminal. Signal strength prediction can be based on a variety of factors, including but not limited to: Distance factor: predict the attenuation of signal strength based on the physical distance between the target access node and the target terminal. Environmental factors: consider the impact of obstacles, buildings, terrain and other factors in the communication environment on signal strength.

[0075] Optionally, the handover request is generated by the target LEO satellite when it is determined that the actual signal strength between the target LEO satellite and the target terminal reaches a pre-handover strength threshold.

[0076] It is understandable that the signal strength and quality between the target terminal and the currently connected LEO satellite is continuously monitored. When the signal strength drops below the pre-switching strength threshold, the LEO satellite and the target terminal can still communicate, but the signal quality will quickly deteriorate due to the movement of the LEO satellite.

[0077] Optionally, the target intensity threshold is greater than the pre-switching intensity threshold.

[0078] It is understandable that the pre-switching strength threshold is a lower signal strength threshold used to trigger the handover preparation process. When the target LEO satellite detects that the actual signal strength between the target terminal and the target terminal reaches or falls below this threshold, a handover request is generated and the search and selection of a new access node begins. This threshold is set to respond in advance to the impending deterioration of signal quality and avoid switching after the signal is completely interrupted, thereby reducing the risk of communication interruption.

[0079] The target strength threshold is a higher signal strength threshold used to select the optimal target access node. When selecting a target access node, it is necessary to ensure that the predicted signal strength between the node and the target terminal is greater than this threshold. This threshold is set to ensure that the target terminal can obtain better communication quality after switching and avoid communication problems caused by insufficient signal strength.

[0080] Exemplarily, the pre-handover strength threshold is set to -110dBm. This means that when the target LEO satellite detects that the actual signal strength between it and the target terminal reaches or falls below -110dBm, a handover request is generated. The target strength threshold is set to -105dBm. This means that when selecting a target access node, it is necessary to ensure that the predicted signal strength between the node and the target terminal is greater than -105dBm. The actual handover threshold is set to -115dBm. This value is lower than the pre-handover strength threshold, indicating that the actual handover process will be triggered when the signal strength further deteriorates to this level.

[0081] S202, controlling the target terminal to disconnect from the target LEO satellite, and accessing the target access node through the target access node.

[0082] It is understandable that the signal strength between the LEO satellite and the target terminal continues to deteriorate as the LEO satellite moves, dropping from the pre-switching strength threshold to the actual switching threshold. At this time, the switching process is triggered, i.e., a switching request response is sent to the target terminal. After receiving the instruction, the target terminal will disconnect the communication link with the currently connected LEO satellite in accordance with the prescribed protocol and process.

[0083] After disconnecting from the current LEO satellite, the target terminal immediately attempts to establish a new communication link with the target access node (which may be another LEO satellite, a MEO satellite, or a ground base station). After the new connection is established, the mobility management system verifies whether the signal strength and quality between the target terminal and the target access node meet the communication requirements. If the signal strength and quality are good, the system confirms that the handover is successful and updates the network connection status of the target terminal.

[0084] In the above-mentioned access node switching method, the present application deploys the mobility management functional unit in the MEO satellite, which can respond to the switching request initiated by the LEO satellite more quickly than the traditional ground network deployment. Since the communication distance between the MEO satellite and the LEO satellite is relatively close and is not limited by the multi-hop transmission of the ground network, the transmission delay of the switching request response can be significantly reduced. The mobility management controller in the MEO satellite can directly control the target terminal to disconnect from the target LEO satellite and access the network through the selected target access node, avoiding the additional delay caused by multi-hop transmission in the traditional method. By directly managing the switching process of the LEO satellite and the ground base station through the MEO satellite, the switching process can be simplified and unnecessary signaling interactions can be reduced. In the traditional ground network deployment method, the switching operation needs to be forwarded and processed by multiple network nodes, resulting in a large signaling overhead. The MEO satellite in this scheme can directly communicate with the target LEO satellite and the candidate access node, thereby effectively reducing the signaling overhead.

[0085] According to the terminal location information reported by the GEO satellite, the mobility management controller can intelligently select the optimal target access node from the candidate LEO satellites and ground base stations based on accurate location information. This intelligent selection method can reduce signaling waste and resource consumption caused by frequent switching and incorrect selection of access nodes. When selecting the target access node, the predicted signal strength between the target terminal and the target terminal is taken into account to ensure that the selected access node can provide stable communication services. This selection method based on predicted signal strength can reduce communication interruptions and reconnection caused by unstable signals, further improving business continuity.

[0086] In an exemplary embodiment, Figure 3 As shown, selecting a target access node from candidate LEO satellites and candidate ground base stations includes:

[0087] S301, obtaining satellite communication information of a candidate LEO satellite and base station communication information of a candidate ground base station.

[0088] Among them, the satellite communication information includes satellite position information and satellite communication resource information, and the base station communication information includes base station position information and base station communication resource information.

[0089] Optionally, for each candidate LEO satellite, a method of obtaining satellite communication information of the candidate LEO satellite includes:

[0090] The satellite position information of the candidate LEO satellite is predicted according to the constellation information and ephemeris information of the candidate LEO satellite.

[0091] It is understandable that constellation information usually describes the overall layout and characteristics of a satellite network consisting of multiple satellites, including the satellite's orbit type (such as circular, elliptical), orbit altitude, orbit inclination, number of satellites, etc. For LEO satellites, constellation information may also include orbital parameters such as the satellite's ascending node right ascension and perigee angular distance, which together determine the satellite's trajectory in space.

[0092] Ephemeris information provides precise position information about a specific satellite at a specific point in time. For LEO satellites, ephemeris information usually includes six orbital parameters of the satellite (such as semi-major axis, eccentricity, orbital inclination, right ascension of ascending node, angular distance of perigee, and mean anomaly) and time parameters, through which the position and speed of the satellite at any time can be calculated.

[0093] Optionally, based on the constellation information, a preliminary estimate of the satellite's approximate position and trajectory can be made. This helps to narrow the prediction range and improve prediction efficiency. Using orbital mechanics models (such as SGP4, SDP4, etc.) and acquired ephemeris information, the satellite's position and velocity at any time can be calculated. These models take into account the effects of multiple factors on satellite orbits, such as the earth's gravity, atmospheric drag, and solar radiation pressure, and can provide highly accurate prediction results.

[0094] Satellite communication resource information of the candidate LEO satellite is determined based on the received signal strength, remaining service time and number of idle channels of the candidate LEO satellite. It can be understood that the received signal strength of the candidate LEO satellite refers to the signal strength received by the candidate LEO satellite from the mobility management controller in the MEO satellite.

[0095] The remaining service time refers to the time that the candidate LEO satellite can continue to provide services to ground terminals in its current orbital position. Based on the satellite's orbital parameters (such as orbital altitude, speed, inclination, etc.) and current position, the satellite's trajectory in the future can be calculated. Combined with the satellite's energy reserves, mission planning and other factors, the satellite's remaining service time can be estimated.

[0096] The number of idle channels refers to the number of unoccupied communication channels on the candidate LEO satellite. It is one of the important indicators to measure the availability of satellite communication resources, and directly affects the communication capacity and service capabilities of the satellite. The occupancy of each channel on the current satellite can be queried through the satellite's network management system or communication controller. The number of idle channels is the total number of channels minus the number of occupied channels.

[0097] S302: Select a target access node from the candidate LEO satellites and the candidate ground base stations according to the terminal location information of the target terminal, the satellite communication information of the candidate LEO satellites and the base station communication information of the candidate ground base stations.

[0098] Optional, such as Figure 4 As shown, according to the terminal location information of the target terminal, the satellite communication information of the candidate LEO satellite and the base station communication information of the candidate ground base station, the target access node is selected from the candidate LEO satellite and the candidate ground base station, including:

[0099] S401, determining whether there is a candidate LEO satellite among the candidate LEO satellites according to the terminal location information of the target terminal and the satellite communication information of the candidate LEO satellites.

[0100] Among them, the predicted signal strength between the candidate LEO satellite and the target terminal is greater than the target strength threshold.

[0101] Optionally, a signal strength prediction model or data is used to predict the signal strength between the satellite and the target terminal in combination with the location information of the target terminal and the orbital parameters and current location of the candidate LEO satellite.

[0102] Then, the predicted signal strength is compared with the target strength threshold. If the predicted signal strength is greater than the target strength threshold, the LEO satellite is considered as a candidate LEO satellite.

[0103] S402: If yes, select a target access node from the candidate LEO satellites.

[0104] In this embodiment, when selecting an access node, the LEO satellite layer is selected first, so as to preferentially implement inter-satellite handover.

[0105] Optionally, if other communication parameters are further considered from the candidate LEO satellites, such as bandwidth, data transmission rate, remaining service time, satellite load, etc., these parameters are comprehensively compared according to the communication requirements and priorities of the target terminal. The LEO satellite that best meets the communication requirements of the target terminal is selected as the target access node.

[0106] For example, ensure that the data transmission needs of the target terminal are met. Select satellites with longer remaining service time to reduce the risk of communication interruption. Select satellites with lighter loads to ensure communication quality and stability.

[0107] S403: If it does not exist, select a target access node from the candidate ground base stations according to the terminal location information of the target terminal and the base station communication information of the ground base station.

[0108] In this embodiment, if the inter-satellite handover cannot be achieved after S402, a satellite-to-ground handover is performed.

[0109] Optionally, no candidate LEO satellite is selected. According to the terminal location information of the target terminal, determine the candidate ground base stations in its area. Obtain the base station communication information of the candidate ground base stations, such as signal strength, bandwidth, data transmission rate, current load, etc. Make a comprehensive comparison of these parameters and select the ground base station that best meets the communication requirements of the target terminal as the target access node.

[0110] Further, such as Figure 5 As shown, according to the terminal position information of the target terminal and the satellite communication information of the candidate LEO satellite, determining whether there is a candidate LEO satellite among the candidate LEO satellites includes:

[0111] S501: Determine whether a first LEO satellite exists among the candidate LEO satellites according to the terminal position information of the target terminal and the satellite position information of the candidate LEO satellites.

[0112] The communication distance between the first LEO satellite and the target terminal is less than a distance threshold, and the predicted signal strength between the first LEO satellite and the target terminal is greater than a target strength threshold.

[0113] It is understood that the communication distance is the actual or predicted distance between the target terminal and the LEO satellite, which determines the path loss and delay of signal transmission. The distance threshold is a preset limit used to determine whether the LEO satellite is close enough to the target terminal to ensure the feasibility and quality of communication.

[0114] The predicted signal strength is estimated based on the location information of the target terminal and the LEO satellite, as well as the parameters of the communication environment. The target strength threshold is the minimum signal strength requirement for the communication system to work properly. When the communication distance is less than the distance threshold, the predicted signal strength is more likely to be greater than the target strength threshold due to the reduced path loss.

[0115] Optionally, there is a close correlation between the distance threshold and the target strength threshold. The setting of the distance threshold affects the prediction result of the signal strength, because the distance is one of the main factors affecting the signal strength. First, it is determined whether the communication distance is less than the distance threshold, which is a preliminary screening condition for determining whether the LEO satellite may become the first LEO satellite. Only on the basis of meeting this condition, will it be further considered whether the predicted signal strength is greater than the target strength threshold.

[0116] S502: If yes, determine whether there is a second LEO satellite in the first LEO satellite that meets the communication requirements in the switching request according to the satellite communication resource information of the first LEO satellite.

[0117] Optionally, the satellite communication resource information of the first LEO satellite is matched with the communication requirements in the handover request to determine whether the first LEO satellite has sufficient communication resources to meet the communication requirements of the target terminal. If the communication resources of the first LEO satellite can meet or exceed the requirements in the handover request, it can be regarded as a qualified second LEO satellite.

[0118] S503: If yes, use the second LEO satellite as a candidate LEO satellite, and determine whether there is a candidate LEO satellite among the candidate LEO satellites.

[0119] Optionally, when there are multiple second LEO satellites, the second LEO can be screened again from the following dimensions, including the following factors:

[0120] (1) Compare the communication resource quality provided by each second LEO satellite, such as bandwidth, data transmission rate, delay, packet loss rate, etc. Select the satellite with the best communication resource quality to ensure that the target terminal can obtain the best communication experience.

[0121] (2) Evaluate the service stability of each second LEO satellite, including the satellite's operating status, failure rate, maintenance history, etc. Select the satellite with the highest service stability to reduce the risk of communication interruption and failure.

[0122] (3) Consider the coverage of each second LEO satellite and the expected communication duration. Select the satellite that can provide the longest duration and widest coverage to the target terminal to ensure the continuity and reliability of communication.

[0123] (4) Analyze the current load of each second LEO satellite, including the number of connected terminals, the amount of ongoing communications, etc. Select satellites with lighter loads to avoid degradation of communication quality or service interruption due to overload.

[0124] If there are multiple second LEO satellites that meet the conditions and they are similar in terms of communication resource quality, service stability, etc., cost-effectiveness factors can be considered. The most cost-effective satellite is selected to optimize the overall communication cost and resource utilization efficiency.

[0125] A weight may be assigned to each factor, and then the satellites may be scored or ranked according to the weight. Based on the result of the comprehensive evaluation, the second LEO satellite with the highest score or the highest ranking is selected as the optimal choice.

[0126] Specifically, the best selected second LEO satellite is used as a candidate LEO satellite, and it is determined that there is a candidate LEO satellite among the candidate LEO satellites.

[0127] In this embodiment, when there are alternative LEO satellites, LEO satellites are preferentially selected as target access nodes to take advantage of their wide coverage and long communication distance. When there are no alternative LEO satellites, the ground base station is turned to select the base station that best meets the communication requirements as the target access node. Through these two steps, it can be ensured that the target terminal can find the most suitable access node in any case to meet its communication needs.

[0128] In an exemplary embodiment, Figure 6 As shown, controlling the target terminal currently communicating with the target LEO satellite to disconnect from the target LEO satellite and access the target access node through the target access node includes:

[0129] S601: When it is determined that the target access node is a candidate LEO satellite, a handover control message is sent to the target access node to instruct the target access node to reserve communication resources that meet the communication requirements in the handover request.

[0130] Optionally, the handover control message includes information such as the type and quantity of communication resources required by the target terminal, as well as the reserved duration. After receiving the handover control message, the target access node reserves the corresponding communication resources according to the requirements in the instruction. After the reservation is successful, the target access node sends a reservation completion response to the mobility management controller in the MEO satellite to confirm that the resources have been reserved.

[0131] The mobility management controller in the MEO satellite sends a handover request response to the target terminal upon receiving the reservation completion response. The handover request response includes the identification information of the target access node, the parameters required for handover, and the guidance information of the handover process.

[0132] After receiving the handover request response, the target terminal parses the instruction content and prepares to perform the handover operation. According to the instructions in the instruction, the target terminal first disconnects the current communication connection with the target LEO satellite. Then, the target terminal attempts to establish a new communication connection with the target access node according to the target access node identification information in the instruction. When the target terminal successfully establishes a communication connection with the target access node, the handover process is completed.

[0133] S602, when a reservation completion response is obtained from the target access node, a switching request response is sent to the target terminal through the target LEO satellite to instruct the target terminal to disconnect from the target LEO satellite and access the target access node through the target access node.

[0134] Optionally, when a reservation completion response is obtained from the target access node, a switching request response is sent to the target terminal via the target LEO satellite, including: when a reservation completion response is obtained from the target access node and it is determined that the actual signal strength between the target LEO satellite and the target terminal is less than the actual switching strength threshold, a switching request response is sent to the target terminal via the target LEO satellite.

[0135] The pre-switching strength threshold is greater than the actual switching strength threshold.

[0136] In an exemplary embodiment, Figure 7 As shown, the specific process of inter-satellite handover of the target terminal v supporting multiple access is as follows, wherein the LEO satellite currently connected by the target terminal v is set to be the LEO satellite n (that is, the above-mentioned target LEO satellite):

[0137] S701, the target terminal v transmits terminal data to the LEO satellite n.

[0138] S702, LEO satellite n receives terminal data and transmits the terminal data to the communication node corresponding to the target terminal v.

[0139] S703, the LEO satellite n moves quickly, and when it is determined that the signal strength between the target terminal v and the LEO satellite n reaches a pre-switching strength threshold, the LEO satellite n sends a switching request to the MEO.

[0140] Specifically, the LEO satellite n sends a switching request to the mobility management controller in the MEO, including the LEO satellite LIDn and the target terminal UIDv that are bound to each other, and sends a switching notification to the target terminal v. At this time, the LEO satellite n and the target terminal v can still communicate.

[0141] S704, LEO satellite n sends a switching notification to the target terminal v.

[0142] The switching notification is used to notify the target terminal v that the LEO satellite n has started the switching process.

[0143] S705, the MEO satellite selects a target access node from candidate LEO satellites and candidate ground base stations according to the handover request initiated by the LEO satellite n and the terminal location information of the target terminal currently communicating with the target LEO satellite reported by the GEO satellite.

[0144] Specifically, the mobility management controller in the MEO satellite queries the identification mapping table to determine the binding information between the LEO satellite n and the target terminal v; then, the MEO satellite selects the optimal LEO satellite m according to the target terminal information and the LEO satellite constellation and ephemeris information in the resource mapping management module, takes the LEO satellite m as the target access node, and replaces the identification information of the LEO satellite n with the information of the LEO satellite m.

[0145] S706, the MEO satellite sends a handover request response to the LEO satellite m.

[0146] S707, LEO satellite n forwards the handover request response to the target terminal v.

[0147] Optionally, the request response is used to instruct the target terminal v to control the target terminal to disconnect from the target LEO satellite and access the LEO satellite m through the LEO satellite m when it is determined that the actual signal strength between the target LEO satellite and the target terminal is less than the actual switching strength threshold.

[0148] S708, the MEO satellite sends a switching control message to the LEO satellite m.

[0149] S709, the LEO satellite m reserves communication resources that meet the communication requirements in the handover request.

[0150] S7010, the MEO satellite sends a routing allocation notification to the communication node corresponding to the target terminal v.

[0151] Optionally, the routing allocation notification is used to instruct the communication node to change the routing path from LEO satellite n to LEO satellite m.

[0152] S7011, LEOm feeds back a completion response to the MEO satellite.

[0153] S7012, the target terminal v responds to the switching request, and triggers an access request when it is determined that the signal strength between the target terminal v and the LEO satellite n reaches an actual switching strength threshold.

[0154] S7013, target terminal v sends an access request to LEO satellite m.

[0155] S7014, LEO satellite m returns an access request response to the target terminal v.

[0156] S7015, the target terminal v responds to the access request and sends the terminal data to the LEO satellite m.

[0157] S7016, LEO satellite m forwards the terminal data to the communication node corresponding to the target terminal v.

[0158] In an exemplary embodiment, Figure 8 As shown, the specific process of satellite-to-ground switching of the target terminal v supporting multiple access is as follows, wherein the LEO satellite currently connected by the target terminal v is set to be the LEO satellite n (that is, the above-mentioned target LEO satellite):

[0159] S801, the target terminal v transmits terminal data to the LEO satellite n.

[0160] S802, LEO satellite n receives terminal data and forwards the terminal data to the communication node corresponding to the target terminal v.

[0161] S803, the LEO satellite n moves quickly, the signal strength between the target terminal v and the LEO satellite n reaches the pre-switching strength threshold, and a switching request is sent to the MEO satellite.

[0162] Specifically, the LEO satellite n sends a switching request to the mobility management controller in the MEO satellite, the switching request including the mutually bound LEO satellite LIDn and the target terminal UIDv, and sends a switching notification to the target terminal v. At this time, the LEO satellite n and the target terminal v can still communicate.

[0163] S804, LEO satellite n sends a switching notification to the target terminal v.

[0164] The switching notification is used to notify the target terminal v that the LEO satellite n has started the switching process.

[0165] S805, the MEO satellite sends the handover request of the LEO satellite n to the mobility management controller on the ground.

[0166] Specifically, the ground mobility management controller queries the identification mapping table to determine the binding information between the LEO satellite n and the target terminal v. According to the terminal location information of the target terminal currently communicating with the target LEO satellite reported by the GEO satellite, and the base station location and base station communication information of each ground base station managed by the ground mobility management controller, the optimal ground base station m is selected from each ground base station managed by the ground mobility management controller, the ground base station m is used as the target access node, and the identification information of the LEO satellite n is replaced with the information of the ground base station m.

[0167] S806: The ground mobility management controller sends a handover response to the MEO satellite.

[0168] Specifically, the handover response includes base station information of the ground base station m.

[0169] S807, the MEO satellite sends a switching control instruction to the base station m according to the received switching response.

[0170] The switching control instruction is used to instruct the ground base station m to execute the switching process.

[0171] S808, the MEO satellite sends a routing allocation notification to the communication node corresponding to the target terminal v.

[0172] S809: Base station m sends a handover control response to the ground mobility management controller according to the received handover control instruction.

[0173] The handover control return indicates that the base station m is ready for the subsequent handover process.

[0174] S8010, the MEO satellite forwards the switching request response to the LEO satellite n according to the switching control response returned by the ground base station m.

[0175] The request response is used to instruct the target terminal v to control the target terminal to disconnect from the target LEO satellite and access the base station m through the base station m when it is determined that the actual signal strength between the target LEO satellite and the target terminal is less than the actual switching strength threshold.

[0176] S8011, LEO satellite n forwards the switching request response to the target terminal v.

[0177] S8012, the target terminal v responds to the switching request and triggers an access request when it is determined that the signal strength between the target terminal v and the LEO satellite n reaches an actual switching strength threshold.

[0178] S8013, the target terminal v sends an access request response to the ground base station m.

[0179] S8014, the ground base station m returns an access request response to the target terminal v.

[0180] S8015, the target terminal v responds to the access request and sends the terminal data to the ground base station m.

[0181] S8016, the ground base station m forwards the terminal data to the communication node corresponding to the target terminal v.

[0182] It should be understood that, although the steps in the flowcharts involved in the above embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0183] Based on the same inventive concept, the embodiment of the present application also provides an access node switching device for implementing the access node switching method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more access node switching device embodiments provided below can refer to the limitations on the access node switching method above, and will not be repeated here.

[0184] In an exemplary embodiment, Fig. 9 As shown, an access node switching device is provided, comprising: a response module 11 and an access control module 12, a mobility management controller configured in a medium earth orbit MEO satellite, the MEO satellite communicates with a geosynchronous orbit GEO satellite, wherein:

[0185] A response module 11 is used to respond to a handover request initiated by a target LEO satellite, and select a target access node from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellite is a LEO satellite other than the target LEO satellite among LEO satellites managed by a MEO satellite, and the candidate ground base station is a ground base station managed by a MEO satellite; and the predicted signal strength between the target access node and the target terminal is greater than a target strength threshold;

[0186] The access control module 12 is used to control the target terminal to disconnect from the target LEO satellite and access the target access node through the target access node.

[0187] In one embodiment, the response module 11 is further used to: obtain satellite communication information of the candidate LEO satellite and base station communication information of the candidate ground base station; wherein the satellite communication information includes satellite position information and satellite communication resource information, and the base station communication information includes base station position information and base station communication resource information;

[0188] A target access node is selected from the candidate LEO satellites and the candidate ground base stations according to the terminal location information of the target terminal, the satellite communication information of the candidate LEO satellites and the base station communication information of the candidate ground base stations.

[0189] In one embodiment, the response module 11 is further used to: determine whether there is a candidate LEO satellite among the candidate LEO satellites according to the terminal position information of the target terminal and the satellite communication information of the candidate LEO satellite; wherein the predicted signal strength between the candidate LEO satellite and the target terminal is greater than the target strength threshold;

[0190] If so, select the target access node from the candidate LEO satellites;

[0191] If not, the target access node is selected from the candidate ground base stations according to the terminal location information of the target terminal and the base station communication information of the ground base station.

[0192] In one of the embodiments, the response module 11 is further used to: determine whether there is a first LEO satellite among the candidate LEO satellites according to the terminal position information of the target terminal and the satellite position information of the candidate LEO satellites; wherein the communication distance between the first LEO satellite and the target terminal is less than a distance threshold, and the predicted signal strength between the first LEO satellite and the target terminal is greater than a target strength threshold;

[0193] If yes, determining whether there is a second LEO satellite that meets the communication requirements in the handover request in the first LEO satellite according to the satellite communication resource information of the first LEO satellite;

[0194] If yes, the second LEO satellite is used as a candidate LEO satellite, and it is determined that there is a candidate LEO satellite among the candidate LEO satellites.

[0195] In one of the embodiments, the access control module 12 is further configured to: when determining that the target access node is a candidate LEO satellite, send a handover control message to the target access node to instruct the target access node to reserve communication resources that meet the communication requirements in the handover request;

[0196] When a reservation completion response is obtained from the target access node, a switching request response is sent to the target terminal through the target LEO satellite to instruct the target terminal to disconnect from the target LEO satellite and access the target access node through the target access node.

[0197] In one of the embodiments, the access control module 12 is further used to: upon obtaining a reservation completion response fed back by the target access node and determining that the actual signal strength between the target LEO satellite and the target terminal is less than an actual switching strength threshold, send a switching request response to the target terminal through the target LEO satellite.

[0198] In one embodiment, the handover request is generated by the target LEO satellite when it is determined that the actual signal strength between the target LEO satellite and the target terminal reaches a pre-handover strength threshold; the target strength threshold is greater than the pre-handover strength threshold, and the pre-handover strength threshold is greater than the actual handover strength threshold.

[0199] In one of the embodiments, the apparatus further comprises an information acquisition module for: predicting, for each candidate LEO satellite, satellite position information of the candidate LEO satellite based on the constellation information and ephemeris information of the candidate LEO satellite;

[0200] Satellite communication resource information of the candidate LEO satellite is determined based on the received signal strength, remaining service time and number of idle channels of the candidate LEO satellite.

[0201] Each module in the access node switching device can be implemented in whole or in part by software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a mobility management controller in a MEO satellite in the form of hardware, or can be stored in a memory in a mobility management controller in a MEO satellite in the form of software, so that the processor can call and execute operations corresponding to each module.

[0202] In an exemplary embodiment, a mobility management controller in a MEO satellite is provided. The mobility management controller may be a server, and its internal structure diagram may be as follows: Fig.10 As shown. The mobility management controller in the MEO satellite includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the mobility management controller in the MEO satellite is used to provide computing and control capabilities. The memory of the mobility management controller in the MEO satellite includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the mobility management controller in the MEO satellite is used to store data of the access node switching method. The input / output interface of the mobility management controller in the MEO satellite is used to exchange information between the processor and an external device. The communication interface of the mobility management controller in the MEO satellite is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, an access node switching method is implemented.

[0203] Those skilled in the art will understand that Fig.10The structure shown in the figure is only a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the mobility management controller in the MEO satellite to which the solution of the present application is applied. The mobility management controller in a specific MEO satellite may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0204] In an exemplary embodiment, a mobility management controller in a MEO satellite is provided, comprising a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0205] In response to a handover request initiated by a target LEO satellite, a target access node is selected from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellite is a LEO satellite other than the target LEO satellite among LEO satellites managed by a MEO satellite, and the candidate ground base station is a ground base station managed by a MEO satellite; and a predicted signal strength between the target access node and the target terminal is greater than a target strength threshold;

[0206] The target terminal is controlled to disconnect from the target LEO satellite and access the target access node through the target access node.

[0207] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0208] In response to a handover request initiated by a target LEO satellite, a target access node is selected from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellite is a LEO satellite other than the target LEO satellite among LEO satellites managed by a MEO satellite, and the candidate ground base station is a ground base station managed by a MEO satellite; and a predicted signal strength between the target access node and the target terminal is greater than a target strength threshold;

[0209] The target terminal is controlled to disconnect from the target LEO satellite and access the target access node through the target access node.

[0210] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the following steps:

[0211] In response to a handover request initiated by a target LEO satellite, a target access node is selected from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellite is a LEO satellite other than the target LEO satellite among LEO satellites managed by a MEO satellite, and the candidate ground base station is a ground base station managed by a MEO satellite; and a predicted signal strength between the target access node and the target terminal is greater than a target strength threshold;

[0212] The target terminal is controlled to disconnect from the target LEO satellite and access the target access node through the target access node.

[0213] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0214] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0215] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0216] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for switching an access node, characterized in that: A mobility management controller applied to a medium earth orbit MEO satellite, the MEO satellite communicating with a geosynchronous orbit GEO satellite, the method comprising: In response to a handover request initiated by a target LEO satellite, a target access node is selected from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellite is a LEO satellite other than the target LEO satellite among LEO satellites managed by a MEO satellite, and the candidate ground base station is a ground base station managed by the MEO satellite; and a predicted signal strength between the target access node and the target terminal is greater than a target strength threshold; The target terminal is controlled to disconnect from the target LEO satellite and access the target access node through the target access node.

2. The method according to claim 1, characterized in that The step of selecting a target access node from candidate LEO satellites and candidate ground base stations comprises: Acquire satellite communication information of a candidate LEO satellite and base station communication information of a candidate ground base station; wherein the satellite communication information includes satellite position information and satellite communication resource information, and the base station communication information includes base station position information and base station communication resource information; A target access node is selected from the candidate LEO satellites and the candidate ground base stations according to the terminal location information of the target terminal, the satellite communication information of the candidate LEO satellites and the base station communication information of the candidate ground base stations.

3. The method according to claim 2, characterized in that The selecting a target access node from the candidate LEO satellite and the candidate ground base station according to the terminal location information of the target terminal, the satellite communication information of the candidate LEO satellite, and the base station communication information of the candidate ground base station comprises: Determining whether there is a candidate LEO satellite among the candidate LEO satellites according to the terminal location information of the target terminal and the satellite communication information of the candidate LEO satellite; wherein the predicted signal strength between the candidate LEO satellite and the target terminal is greater than a target strength threshold; If so, selecting a target access node from the candidate LEO satellite; If not, a target access node is selected from the candidate ground base stations according to the terminal location information of the target terminal and the base station communication information of the ground base station.

4. The method according to claim 3, characterized in that The determining, based on the terminal location information of the target terminal and the satellite communication information of the candidate LEO satellite, whether there is a candidate LEO satellite among the candidate LEO satellites comprises: Determine whether there is a first LEO satellite among the candidate LEO satellites according to the terminal position information of the target terminal and the satellite position information of the candidate LEO satellites; wherein a communication distance between the first LEO satellite and the target terminal is less than a distance threshold, and a predicted signal strength between the first LEO satellite and the target terminal is greater than a target strength threshold; If yes, determining whether there is a second LEO satellite that meets the communication requirements in the switching request in the first LEO satellite according to the satellite communication resource information of the first LEO satellite; If so, the second LEO satellite is used as a candidate LEO satellite, and it is determined that there is a candidate LEO satellite among the candidate LEO satellites.

5. The method according to any one of claims 1 to 4, characterized in that: The controlling the target terminal currently communicating with the target LEO satellite to disconnect from the target LEO satellite and access the target access node through the target access node comprises: In the case where it is determined that the target access node is a candidate LEO satellite, sending a handover control message to the target access node to instruct the target access node to reserve communication resources that meet the communication requirements in the handover request; When a reservation completion response is obtained from the target access node, a switching request response is sent to the target terminal through the target LEO satellite to instruct the target terminal to disconnect from the target LEO satellite and access the target access node through the target access node.

6. The method according to claim 5, characterized in that The step of sending a handover request response to the target terminal through the target LEO satellite when a reservation completion response fed back by the target access node is obtained includes: When a reservation completion response fed back by the target access node is obtained and it is determined that the actual signal strength between the target LEO satellite and the target terminal is less than the actual switching strength threshold, a switching request response is sent to the target terminal through the target LEO satellite.

7. The method according to claim 6, characterized in that The switching request is generated by the target LEO satellite when it is determined that the actual signal strength between the target LEO satellite and the target terminal reaches a pre-switching strength threshold; the target strength threshold is greater than the pre-switching strength threshold, and the pre-switching strength threshold is greater than the actual switching strength threshold.

8. The method according to claim 2, characterized in that: The method further comprises: For each candidate LEO satellite, predict satellite position information of the candidate LEO satellite according to the constellation information and ephemeris information of the candidate LEO satellite; Satellite communication resource information of the candidate LEO satellite is determined according to the received signal strength, remaining service time and number of idle channels of the candidate LEO satellite.

9. An access node switching device, characterized in that: A mobility management controller configured in a medium earth orbit MEO satellite, the MEO satellite communicating with a geosynchronous orbit GEO satellite, the device comprising: A response module, configured to respond to a handover request initiated by a target LEO satellite, and select a target access node from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellite is a LEO satellite other than the target LEO satellite among LEO satellites managed by a MEO satellite, and the candidate ground base station is a ground base station managed by the MEO satellite; and the predicted signal strength between the target access node and the target terminal is greater than a target strength threshold; The access control module is used to control the target terminal to disconnect from the target LEO satellite and access the target access node through the target access node.

10. A mobility management controller in a MEO satellite, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

12. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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