Access node handover method, apparatus, and mobility management controller in MEO satellite

Abstract

The application relates to the technical field of communication, in particular to an access node switching method, an access node switching device and a mobility management controller in a 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 satellite, and the candidate ground base stations are ground base stations managed by the MEO satellite; the predicted signal strength between the target access node and the target terminal is greater than a target strength threshold; and the target terminal is controlled to disconnect the connection with the target LEO satellite and access the target access node through the target access node.

Description

TECHNICAL FIELD

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

[0002] With the gradual maturity of the global 5th Generation Mobile Communication Technology (5G) network, research on the 6th Generation Mobile Communication Technology (6G) has begun; among them, the global seamless connection demand in 6G network technology is one of the research hotspots.

[0003] Traditional ground networks rely on basic settings such as base stations, and have low global communication coverage, making it difficult to provide ubiquitous and seamless communication services for users in remote areas such as oceans, deserts and valleys. The rapid development of Non-Terrestrial Network (NTN) has well compensated for this deficiency. Satellites, as access nodes or relay nodes, expand the communication range and integrate with ground networks to create a global coverage, seamless connection network system, effectively overcoming geographical limitations and providing users with anytime, anywhere high-reliability, large-bandwidth seamless communication services.

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

[0005] However, due to the high speed of LEO satellites, the network topology changes dynamically, and the target terminal needs to frequently switch access satellites. In order to ensure business continuity and ensure uninterrupted service, switching needs to be performed during satellite and target terminal movement. Since the current mobile management function unit is deployed in the ground network, when switching operations are performed, 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

[0006] Therefore, it is necessary to provide an access node switching method, device and mobility management controller in a MEO satellite to reduce signaling overhead.

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

[0008] In response to a switching request initiated by a target low earth orbit (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 the GEO satellite, wherein the candidate LEO satellites are LEO satellites managed by the MEO satellite except the target LEO satellite, the candidate ground base stations are ground base stations 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;

[0009] Controlling the target terminal to disconnect a connection with the target LEO satellite and access the target access node through the target access node.

[0010] In one of the embodiments, the selecting of the target access node from the candidate LEO satellites and the candidate ground base stations comprises:

[0011] Obtaining satellite communication information of the candidate LEO satellites and base station communication information of the candidate ground base stations, wherein the satellite communication information comprises satellite location information and satellite communication resource information, and the base station communication information comprises base station location information and base station communication resource information;

[0012] Selecting the 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.

[0013] In one of the embodiments, the selecting of the 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 comprises:

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

[0015] If there is, selecting the target access node from the candidate LEO satellite;

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

[0017] In one of the embodiments, according to the terminal location information of the target terminal and the satellite communication information of the candidate LEO satellite, it is determined whether there is an alternative LEO satellite in the candidate LEO satellite, comprising:

[0018] According to the terminal location information of the target terminal and the satellite location information of the candidate LEO satellite, it is determined whether there is a first LEO satellite in the candidate LEO satellite; wherein the communication distance between the first LEO satellite and the target terminal is less than the distance threshold, and the predicted signal strength between the first LEO satellite and the target terminal is greater than the target strength threshold;

[0019] If so, according to the satellite communication resource information of the first LEO satellite, it is determined whether there is a second LEO satellite in the first LEO satellite that meets the communication requirement in the handover request;

[0020] If so, the second LEO satellite is taken as the alternative LEO satellite, and it is determined that there is an alternative LEO satellite in the candidate LEO satellite.

[0021] In one of the embodiments, the target terminal currently communicating with the target LEO satellite is controlled to disconnect the connection between the target terminal and the target LEO satellite, and access the target access node through the target access node, comprising:

[0022] In the case of determining that the target access node is the candidate LEO satellite, a handover control message is sent to the target access node to instruct the target access node to reserve the communication resource meeting the communication requirement in the handover request;

[0023] In the case of obtaining the reservation completion response fed back by the target access node, a handover request response is sent to the target terminal through the target LEO satellite to instruct the target terminal to disconnect the connection between the target terminal and the target LEO satellite, and access the target access node through the target access node.

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

[0025] In the case of obtaining the 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 the actual handover strength threshold, a handover request response is sent to the target terminal through the target LEO satellite.

[0026] In one of the embodiments, the handover request is generated by the target LEO satellite in a case 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 of the embodiments, the method further comprises:

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

[0029] Determining satellite communication resource information of the candidate LEO satellite according to the received signal strength, the remaining service time and the number of idle channels of the candidate LEO satellite.

[0030] In a second aspect, the application further provides an access node handover device applied to a mobility management controller in a medium earth orbit (MEO) satellite, the MEO satellite being in communication with a geosynchronous earth orbit (GEO) satellite, and the device comprising:

[0031] A response module configured to, in response to a handover request initiated by a target LEO satellite, select a target access node from candidate LEO satellites and candidate ground base stations according to terminal position information of a target terminal currently in communication with the target LEO satellite reported by the GEO satellite; wherein the candidate LEO satellites are LEO satellites managed by the MEO satellite except for the target LEO satellite, and the candidate ground base stations are ground base stations 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.

[0032] An access control module configured to control the target terminal to disconnect a connection between the target terminal and the target LEO satellite, and access the target access node through the target access node.

[0033] In a third aspect, the application further provides a mobility management controller in a MEO satellite, comprising a memory and a processor, the memory storing a computer program, and the processor implementing the following steps when executing the computer program:

[0034] 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 position information of a target terminal currently in communication with the target LEO satellite reported by a GEO satellite; wherein the candidate LEO satellites are LEO satellites managed by the MEO satellite except for the target LEO satellite, and the candidate ground base stations are ground base stations 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.

[0035] controlling the target terminal 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 provides a computer readable storage medium, having stored thereon a computer program, which when executed by a processor, implements the following steps:

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

[0038] controlling the target terminal 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 also provides a computer program product, comprising a computer program, which when executed by a processor, implements the following steps:

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

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

[0042] The access node switching method, device and mobility management controller in the MEO satellite of the present application deploy the mobility management function unit in the MEO satellite, which can respond to the switching request initiated by the LEO satellite more quickly compared with the traditional ground network deployment. Since the communication distance between the MEO satellite and the LEO satellite is relatively short 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 the connection with 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 way. 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 interaction can be reduced. In the traditional ground network deployment, the switching operation needs to be forwarded and processed by multiple network nodes, resulting in large signaling overhead. The MEO satellite in the present application can directly communicate with the target LEO satellite and the candidate access node, thereby effectively reducing the signaling overhead.

[0043] According to the terminal position information reported by the GEO satellite, based on accurate position information, the mobility management controller can intelligently select the optimal target access node from the candidate LEO satellite and the ground base station. This intelligent selection method can reduce the waste of signaling 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 is considered to ensure that the selected access node can provide stable communication services. This selection method based on predicted signal strength can reduce the communication interruption and reconnection phenomenon caused by unstable signals, further improving the service continuity. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments of the present application or the related art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other related drawings can also be obtained without creative labor.

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

[0046] Figure 2 A flowchart of the access node switching method in one embodiment;

[0047] Figure 3 A flowchart of the step of selecting the target access node from the candidate LEO satellite and the candidate ground base station in one embodiment;

[0048] Figure 4 Another embodiment is a flowchart of a method for selecting a target access node from candidate LEO satellites and candidate ground base stations;

[0049] Figure 5 Another embodiment is a flowchart of a method for determining whether there is an alternative LEO satellite in the candidate LEO satellites;

[0050] Figure 6 Another embodiment is a flowchart of a method for accessing a target access node through the target access node;

[0051] Figure 7 Another embodiment is an interaction diagram of an inter-satellite handover corresponding to the access node handover method;

[0052] Figure 8 Another embodiment is an interaction diagram of an inter-satellite handover corresponding to the access node handover method;

[0053] Figure 9 Another embodiment is a structural block diagram of an access node handover device;

[0054] Figure 10 Another embodiment is an internal structure diagram of a mobility management controller in a MEO satellite. DETAILED DESCRIPTION

[0055] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0056] Space-ground cooperation refers to the 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.) in the construction and operation of communication networks. Space-ground cooperation can fully utilize the advantages of ground networks and space networks, and achieve complementary advantages. Ground networks provide stable and high-speed communication services, while space networks have extensive coverage and can compensate for the coverage blind spots of ground networks. In remote areas, oceans, deserts and other places where ground networks are difficult to cover, space-ground cooperation technology can provide seamless, efficient and reliable communication services for users.

[0057] Mobility management refers to a series of techniques and strategies adopted in communication networks to ensure the continuity, stability and efficiency of communication for users or terminal devices during movement. Mobility management technology can track and predict the location information of users in real time, and timely adjust network resources, update data routing and perform seamless switching of connections when users switch from one access node to another.

[0058] Identity mapping is a mechanism that establishes a correspondence between the identity of a user or device (such as a user ID, device serial number, etc.) and the location in the network (such as an IP address, satellite orbital position, etc.) in a network environment, especially in a complex architecture like the integrated space-ground 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 located. This is crucial for implementing communication and mobility management between different network nodes. In the integrated space-ground 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 communication continuity.

[0059] For example, assume there is an integrated space-ground network that 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. Ground user case: Identity: User A, user ID is 12345. Location: User A is currently connected to ground base station B, and the IP address of base station B is 192.168.1.1. Identity mapping: The network establishes 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 based on user A's user ID through identity mapping, and then route data to the location where user A is located.

[0060] Satellite user case: Identity: User C, device serial number is XYZ123. Location: User C is currently accessing the network through satellite D, and the orbital position of satellite D is a specific location in LEO (Low Earth Orbit). Identity mapping: The network establishes a mapping relationship between 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 data to the location where user C is located.

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

[0062] The aforementioned identifier mapping can be implemented using an Infinite Development Magic Server (IDMS). In traditional technology, the IDMS is deployed on a terrestrial network. When low-Earth orbit (LEO) satellites move frequently, mobile nodes (MNs) need to register with the terrestrial IDMS and update mapping relationships when switching from one access satellite node to another.

[0063] However, due to the long signal transmission distance and significant propagation delay, handover latency increases, affecting the continuity and real-time performance of communication services. Furthermore, each MN move handover involves frequent signaling interactions with the ground-based IDMS, such as registration and updating mapping relationships. The large amount of signaling transmitted between the satellite and the ground consumes valuable communication bandwidth resources, increases signaling overhead, and reduces network efficiency.

[0064] To address the aforementioned technical problems, the access node switching method provided in this application embodiment can be applied to, for example... Figure 1 The illustrated application environment diagram demonstrates a system architecture for a space-ground collaborative mobility management mechanism based on identifier mapping. This mechanism aims to address the issues of high-speed LEO satellite movement, user identity and location binding leading to service discontinuity, handover latency, and signaling loss in space-based networks. The system architecture includes a ground segment and a satellite segment. The ground segment comprises multiple access target terminals and the terrestrial network, while the satellite segment includes the LEO satellite layer, MEO layer, and GEO layer. Identifier-based space-ground collaborative mobility management can be divided into inter-satellite handover and satellite-to-ground handover. Upon handover triggering, based on the terminal status of the target terminal and the status awareness data of candidate LEO satellites in the LEO satellite layer, the optimal satellite / ground base station is selected for handover. The mobility management servers in the MEO satellite layer and the terrestrial network complete the unbinding and binding of identifier mappings, ultimately achieving mobility management for multiple access target terminals and ensuring user service continuity. LEO satellites and base stations serve as access nodes for target terminals, enabling them to select the optimal access node for communication services using various access methods. Furthermore, the LEO satellite network also handles data storage and forwarding. Each MEO satellite is equipped with the same mobility management controller as the terrestrial network, responsible for the identification binding and handover management between LEO satellites and multiple access target terminals within its coverage area. Similarly, the terrestrial network mobility management server is responsible for the identification binding and handover management between base stations and multiple access target terminals. When a satellite-to-ground handover occurs, the MEO satellite exchanges signaling with the terrestrial network mobility management controller through the satellite ground station to complete the handover process.

[0065] In one exemplary embodiment, such as Figure 2As shown, an access node switching method is provided, and the method is applied to Figure 1 The access node switching method is described by 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 comprises the following steps of:

[0066] S201, 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 the GEO satellite.

[0067] Optionally, Figure 1 All network entities in the space-ground cooperative mobility management system architecture have identity information of an identity identifier, including an identity identifier UID of a target terminal, an identity identifier LID of a LEO satellite, an identity identifier MID of a MEO satellite, an identity identifier GID of a GEO satellite, an identity identifier BID of a ground base station, and an identity identifier GMID of a ground network mobility management controller.

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

[0069] It is assumed that in the initial stage, a user terminal currently communicating with the target LEO satellite is a target terminal, and the target LEO satellite provides access services for the multi-access target terminal, at this time, the user UID is bound to the target LEO satellite LID one-to-one, and is stored in the MEO satellite identity mapping management module, with the rapid movement of the target LEO satellite, gradually away from the target terminal, the communication signal between the target terminal and the target LEO satellite will gradually weaken, when the signal strength decreases to a certain threshold, a switching request is triggered, in order to ensure the user service continuity, the target terminal needs to be allocated to the next suitable access node for connection.

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

[0071] It can be understood that, due to the geosynchronous nature and wide coverage range of the GEO satellite, it can provide relatively accurate position information, and the accurate terminal position information provides accuracy guarantee for the subsequent selection of the target access node.

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

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

[0074] It can be understood that signal strength is one of the important indicators to measure communication quality. When the terminal moves from one access node to another access node, in order to ensure the continuity and quality of communication, it is necessary to select an access node with sufficient signal strength as the target access node. In this way, the terminal can maintain stable communication connection after switching or reconnecting. Due to the variability and complexity of the communication environment, direct measurement of the signal strength between the target access node and the target terminal may present certain challenges. Signal strength prediction can be based on a variety of factors, including but not limited to: distance factor: predicting the attenuation of signal strength according to the physical distance between the target access node and the target terminal. Environmental factors: considering the influence of obstacles, buildings, terrain, etc. in the communication environment on signal strength.

[0075] Optionally, the handover request is generated by the target LEO satellite in the case where the actual signal strength between the target LEO satellite and the target terminal reaches the pre-handover strength threshold,

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

[0077] Optionally, the target strength threshold is greater than the pre-handover strength threshold.

[0078] It can be understood that the pre-handover strength threshold is a lower signal strength threshold used to trigger the handover preparation process. When the target LEO satellite monitors that the actual signal strength between the target LEO satellite and the target terminal reaches or is lower than this threshold, a handover request will be generated and the search and selection of a new access node will be started. This threshold is set to anticipate the deteriorating signal quality in advance, so as to avoid switching only 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 the target access node, it is necessary to ensure that the predicted signal strength between the target access 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 handover, avoiding communication problems caused by insufficient signal strength.

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

[0081] S202, control the target terminal to disconnect the connection between the target LEO satellite and the target access node through the target access node.

[0082] It can be understood that the signal strength between the LEO satellite and the target terminal continues to deteriorate as the LEO satellite moves, from the pre-handover strength threshold to the actual handover threshold, at which point the handover process is triggered, i.e. a handover 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 according to the specified protocol and process.

[0083] After disconnecting with the current LEO satellite, the target terminal will immediately attempt to establish a new communication link with the target access node (which can be another LEO satellite, MEO satellite or ground base station). After the new connection is established, the mobility management system will verify 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 will confirm that the handover is successful and update the network connection state of the target terminal.

[0084] In the access node switching method, the mobility management function unit is deployed in the MEO satellite, which can respond to the switching request initiated by the LEO satellite more quickly compared with the traditional ground network deployment. Since the communication distance between the MEO satellite and the LEO satellite is relatively short and is not limited by 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 the connection with 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 way. 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 interaction can be reduced. In the traditional ground network deployment, the switching operation needs to be forwarded and processed by multiple network nodes, resulting in large signaling overhead. The MEO satellite in the present solution can directly communicate with the target LEO satellite and the candidate access node, thereby effectively reducing the signaling overhead.

[0085] According to the terminal position information reported by the GEO satellite, based on accurate position information, the mobility management controller can intelligently select the optimal target access node from the candidate LEO satellite and the ground base station. This intelligent selection method can reduce the 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 is considered to ensure that the selected access node can provide stable communication services. This selection method based on predicted signal strength can reduce the communication interruption and reconnection phenomenon caused by unstable signals, further improving the service continuity.

[0086] In an exemplary embodiment, as shown in FIG. 1, the target access node is selected from the candidate LEO satellite and the candidate ground base station, including: Figure 3

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

[0088] 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, the satellite communication information of the candidate LEO satellite is obtained in the following manner:

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

[0091] ​It can be understood that the constellation information generally describes the overall layout and characteristics of a satellite network composed of multiple satellites, including the orbit type of the satellite (such as circular, elliptical), the orbit height, the orbit inclination, the number of satellites, etc. For LEO satellites, the constellation information can also include the orbital parameters of the satellite, such as the right ascension of the ascending node and the argument of perigee, which together determine the satellite's orbit in space.

[0092] The ephemeris information provides accurate position information about a specific satellite at a specific time point. For LEO satellites, the ephemeris information generally includes the orbital six elements of the satellite (such as semi-major axis, eccentricity, orbit inclination, right ascension of the ascending node, argument of perigee, and mean anomaly) and time parameters, from which the position and velocity of the satellite at any time can be calculated.

[0093] Optionally, according to the constellation information, the approximate position and orbit of the satellite can be preliminarily estimated. This helps to narrow the prediction range and improve the prediction efficiency. Using the orbital mechanics model (such as SGP4, SDP4, etc.) and the obtained ephemeris information, the position and velocity of the satellite at any time can be calculated. These models take into account the effects of factors such as Earth's gravity, atmospheric drag, solar radiation pressure, etc. on the satellite's orbit, and can provide high-precision prediction results.

[0094] According to the received signal strength, the remaining service time, and the number of idle channels of the candidate LEO satellite, the satellite communication resource information of the candidate LEO satellite is determined. 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 for the ground terminal at the current orbit position. According to the orbital parameters of the satellite (such as orbit height, speed, inclination, etc.) and the current position, the orbit of the satellite in the future can be calculated. Combined with factors such as the energy reserve of the satellite, the mission planning, etc., the remaining service time of the satellite can be estimated.

[0096] The number of idle channels refers to the number of communication channels on the candidate LEO satellite that are currently not occupied. It is one of the important indicators for measuring the availability of satellite communication resources, and directly affects the communication capacity and service ability of the satellite. The occupation status of each channel on the satellite can be queried through the network management system or communication controller of the satellite. The number of idle channels is the total number of channels minus the number of occupied channels.

[0097] S302, according to the terminal position 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, selecting a target access node from the candidate LEO satellite and the candidate ground base station.

[0098] Optionally, as shown in Figure 4 The selecting of the 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 comprises:

[0099] S401, determining whether there is an alternative LEO satellite in 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] Wherein, the predicted signal strength between the alternative LEO satellite and the target terminal is greater than the target strength threshold.

[0101] Optionally, the signal strength between the satellite and the target terminal is predicted by using a signal strength prediction model or data, in combination with the location information of the target terminal and the orbit parameters and the current position 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 regarded as an alternative LEO satellite,

[0103] S402, if there is, selecting the target access node from the alternative LEO satellites.

[0104] In this embodiment, when the access node is selected, the selection is preferentially performed in the LEO satellite layer to preferentially realize inter-satellite switching.

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

[0106] For example, it is ensured that the data transmission requirements of the target terminal are met. The satellite with longer remaining service time is selected to reduce the risk of communication interruption. The satellite with lighter load is selected to ensure the communication quality and stability.

[0107] S403, if not, selecting the 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 stations.

[0108] In this embodiment, if the inter-satellite switching is not realized through S402, the satellite-ground switching is performed.

[0109] Optionally, no candidate LEO satellite is screened out. According to the terminal location information of the target terminal, candidate ground base stations in the region where the target terminal is located are determined. The base station communication information of the candidate ground base stations, such as signal strength, bandwidth, data transmission rate, current load, etc., is obtained. These parameters are comprehensively compared, and the ground base station that best meets the communication requirements of the target terminal is selected as the target access node.

[0110] Further, as shown in Figure 5 According to the terminal location information of the target terminal and the satellite communication information of the candidate LEO satellites, it is determined whether there is a candidate LEO satellite in the candidate LEO satellites, including:

[0111] S501, according to the terminal location information of the target terminal and the satellite location information of the candidate LEO satellites, it is determined whether there is a first LEO satellite in the candidate LEO satellites.

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

[0113] It can be 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 for determining 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, and the parameters of the communication environment. The target strength threshold is the minimum signal strength requirement for the communication system to work normally. 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 decrease in path loss.

[0115] Optionally, there is a close relationship 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 can become the first LEO satellite. Only on the basis of meeting this condition, it will be further considered whether the predicted signal strength is greater than the target strength threshold.

[0116] S502, if there is, according to the satellite communication resource information of the first LEO satellite, it is determined whether there is a second LEO satellite in the first LEO satellite that meets the communication requirements in the switching request.

[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 considered as a second LEO satellite that meets the conditions.

[0118] S503, if there is, the second LEO satellite is selected as the candidate LEO satellite, and it is determined that there is a candidate LEO satellite in the candidate LEO satellite.

[0119] Optionally, in the case where there are multiple second LEO satellites, the second LEO satellites can be further screened 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 the target terminal can obtain the best communication experience.

[0121] (2) Evaluate the service stability of each second LEO satellite, including the running state, 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 range and expected communication duration of each second LEO satellite. Select the satellite that can provide the longest duration and the widest coverage for the target terminal to ensure the continuity and reliability of communication.

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

[0124] If there are multiple second LEO satellites that meet the conditions, and they are not much different in terms of communication resource quality, service stability, etc., the cost-effectiveness factor can be considered. Select the satellite with the highest cost-effectiveness to optimize the overall communication cost and resource utilization efficiency.

[0125] A weight can be assigned to each factor, and then the satellites are scored or ranked according to the weight. Based on the results 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 second LEO satellite selected as the optimal choice is selected as the candidate LEO satellite, and it is determined that there is a candidate LEO satellite in the candidate LEO satellite.

[0127] In the embodiment, the LEO satellite is selected as the target access node in the presence of an alternative LEO satellite, so as to take advantage of its wide coverage and long communication distance. In the absence of an alternative LEO satellite, the ground base station is switched to, and the target access node that best meets the communication requirement is selected as the target access node. Through the two steps, the target terminal can find the most suitable access node in any case and meet its communication requirement.

[0128] In one exemplary embodiment, as shown in Figure 6 the target terminal currently in communication with the target LEO satellite is disconnected from the target LEO satellite, and the target terminal accesses the target access node through the target access node, including:

[0129] S601, in the case where 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 requirement in the handover request.

[0130] Optionally, the handover control message contains the type and quantity of communication resources required by the target terminal, and information such as the length of time reserved. 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, confirming that the resources have been reserved.

[0131] The mobility management controller in the MEO satellite sends a handover request response to the target terminal in the case where the reservation completion response is received. The handover request response contains 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 guidance 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 identification information of the target access node in the instruction. When the target terminal successfully establishes a communication connection with the target access node, the handover process is completed.

[0133] S602, in the case where the reservation completion response feedback by the target access node is obtained, a handover request response is sent to the target terminal through the target LEO satellite to instruct the target terminal to disconnect the connection with the target LEO satellite and access the target access node through the target access node.

[0134] Optionally, in the case that the reservation completion response fed back by the target access node is acquired, a handover request response is sent to the target terminal through the target LEO satellite, including: in the case that the reservation completion response fed back by the target access node is acquired and the actual signal strength between the target LEO satellite and the target terminal is determined to be less than the actual handover strength threshold, a handover request response is sent to the target terminal through the target LEO satellite.

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

[0136] In one example, as shown in FIG. 7, Figure 7 The target terminal v supporting multiple accesses has the following specific process in the inter-satellite handover, where the LEO satellite currently connected by the target terminal v is LEO satellite n (i.e., the target LEO satellite mentioned above):

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

[0138] S702, the LEO satellite n receives the 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 in the case that the signal strength between the target terminal v and the LEO satellite n reaches the pre-handover strength threshold, the LEO satellite n sends a handover request to the MEO.

[0140] Specifically, the LEO satellite n sends the handover request to the mobility management controller in the MEO, and the handover request includes the LEO satellite LIDn and the target terminal UIDv bound to each other, and sends a handover notification to the target terminal v at the same time, at this time, the LEO satellite n and the target terminal v can still communicate.

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

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

[0143] S705, the MEO satellite selects the target access node from the candidate LEO satellite and the candidate ground base station 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 identity mapping table to determine the binding information of 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 in the resource mapping management module and the LEO satellite constellation and ephemeris information, takes the LEO satellite m as the target access node, and replaces the identity 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, the 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 the connection between the target terminal and the target LEO satellite and access the LEO satellite m through the LEO satellite m in a case where the actual signal strength between the target LEO satellite and the target terminal is determined to be less than the actual handover strength threshold.

[0148] S708, the MEO satellite sends a handover 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 a 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 the LEO satellite n to the LEO satellite m.

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

[0153] S7012, the target terminal v triggers an access request according to the handover request response in a case where the signal strength between the target terminal v and the LEO satellite n is determined to reach the actual handover strength threshold.

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

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

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

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

[0158] In one example,Figure 8 As shown, the target terminal v supporting multiple accesses has the following star-ground switching specific process, wherein the LEO satellite currently connected by the target terminal v is set as LEO satellite n (i.e. the above target LEO satellite):

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

[0160] S802, the LEO satellite n receives the 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 a 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 includes the mutually bound LEO satellite LIDn and the target terminal UIDv, and a switching notification is sent to the target terminal v at the same time, at this time, the LEO satellite n and the target terminal v can still communicate.

[0163] S804, the 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 switching request of the LEO satellite n to the ground mobility management controller.

[0166] Specifically, the ground mobility management controller queries the identification mapping table to determine the binding information of the LEO satellite n and the target terminal v. According to the terminal position information of the target terminal currently communicating with the target LEO satellite reported by the GEO satellite, and the base station position 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 taken as a target access node, and the identification information of the LEO satellite n is replaced by the information of the ground base station m.

[0167] S806, the ground mobility management controller sends a switching response to the MEO satellite.

[0168] Specifically, the switching response includes the 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 handover control instruction is used to instruct the ground base station m to perform the handover procedure.

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

[0172] S809, the 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 response indicates that the base station m is ready for the subsequent handover procedure.

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

[0175] The request response is used to instruct the target terminal v to disconnect the connection between the target terminal and the target LEO satellite and access the base station m through the base station m in the case where the actual signal strength between the target LEO satellite and the target terminal is determined to be less than the actual handover strength threshold.

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

[0177] S8012, the target terminal v triggers an access request in the case where the signal strength between the target terminal v and the LEO satellite n is determined to reach the actual handover strength threshold according to the handover request response.

[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 sends terminal data to the ground base station m according to the access request response.

[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 shown in sequence according to the arrows, the steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, the execution of the steps is not strictly limited in sequence, and the steps can be executed in other orders. Moreover, at least some of the steps in the flowcharts involved in the above embodiments can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of the steps or stages is not necessarily sequential, but can be alternately executed with at least part of other steps or steps or stages in other steps.

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

[0184] In one exemplary embodiment, as shown in Figure 9 An access node switching device is provided, comprising: a response module 11 and an access control module 12, configured in a mobility management controller in a medium earth orbit (MEO) satellite, the MEO satellite being in communication with a geosynchronous earth orbit (GEO) satellite, wherein:

[0185] The response module 11 is configured to select a target access node from candidate LEO satellites and candidate ground base stations according to terminal location information of a target terminal currently in communication with the target LEO satellite reported by the GEO satellite, in response to a handover request initiated by the target LEO satellite; wherein the candidate LEO satellites are LEO satellites managed by the MEO satellite except for the target LEO satellite, and the candidate ground base stations are ground base stations 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 value.

[0186] The access control module 12 is configured to control the target terminal to disconnect the connection with 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 configured to obtain satellite communication information of the candidate LEO satellites and base station communication information of the candidate ground base stations; wherein the satellite communication information includes satellite location information and satellite communication resource information, and the base station communication information includes base station location information and base station communication resource information.

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

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

[0190] If there is, the target access node is selected from the candidate LEO satellite.

[0191] If there is 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 stations.

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

[0193] If there is, it is determined whether there is a second LEO satellite satisfying the communication requirement in the handover request according to the satellite communication resource information of the first LEO satellite.

[0194] If there is, the second LEO satellite is taken as the candidate LEO satellite, and it is determined that there is the candidate LEO satellite between the target terminal and the candidate LEO satellites.

[0195] In one of the embodiments, the access control module 12 is further configured to: in the case that the target access node is the candidate LEO satellite, send a handover control message to the target access node to instruct the target access node to reserve the communication resource satisfying the communication requirement in the handover request.

[0196] In the case that the reservation completion response fed back by the target access node is acquired, a handover request response is sent to the target terminal through the target LEO satellite to instruct the target terminal to disconnect the connection between the target terminal and 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 configured to: in the case that the reservation completion response fed back by the target access node is acquired, and the actual signal strength between the target LEO satellite and the target terminal is less than the actual handover strength threshold, a handover request response is sent to the target terminal through the target LEO satellite.

[0198] In one of the embodiments, the handover request is generated by the target LEO satellite in a case that the actual signal strength between the target terminal and the target LEO satellite reaches a target 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 obtaining module configured to: for each candidate LEO satellite, predict satellite position information of the candidate LEO satellite according to constellation information and ephemeris information of the candidate LEO satellite;

[0200] According to the received signal strength, the remaining service time and the number of idle channels of the candidate LEO satellite, determine satellite communication resource information of the candidate LEO satellite.

[0201] The modules in the access node handover apparatus can be all or part realized by software, hardware and combination thereof. The modules can be embedded in or independent of a processor in a mobility management controller in a MEO satellite in hardware form, or stored in a memory in the mobility management controller in a MEO satellite in software form, so as to be called and executed by a processor to perform operations corresponding to the modules.

[0202] In one exemplary embodiment, a mobility management controller in a MEO satellite is provided, which can be a server, and an internal structure diagram thereof can be as shown in Figure 10 The mobility management controller in the MEO satellite includes a processor, a memory, an input / output interface (I / O) and a communication interface. 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. The processor of the mobility management controller in the MEO satellite is configured 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 operating system and the computer program in the non-volatile storage medium to run. The database of the mobility management controller in the MEO satellite is configured to store data of the access node handover method. The input / output interface of the mobility management controller in the MEO satellite is configured to exchange information between the processor and external devices. The communication interface of the mobility management controller in the MEO satellite is configured to communicate with external terminals through network connection. The computer program is executed by the processor to implement an access node handover method.

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

[0204] In one exemplary embodiment, a mobility management controller in a MEO satellite is provided, comprising a memory and a processor, the memory storing a computer program, and the processor implementing the following steps when executing the computer program:

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

[0206] Controlling the target terminal to disconnect the connection between the target terminal and the target LEO satellite, and accessing the target access node through the target access node.

[0207] In one embodiment, a computer readable storage medium is provided, having stored thereon a computer program, the computer program being executed by a processor to implement the following steps:

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

[0209] Controlling the target terminal to disconnect the connection between the target terminal and the target LEO satellite, and accessing the target access node through the target access node.

[0210] In one embodiment, a computer program product is provided, comprising a computer program, the computer program being executed by a processor to implement the following steps:

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

[0212] The target terminal is controlled to disconnect the connection between the target terminal and 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 equipment information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of related data need to comply with relevant regulations.

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

[0215] The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, it should be considered as the scope of the present application.

[0216] The above-described embodiments are merely illustrative of several embodiments of the present application, and the description is relatively specific and detailed, but should not be understood as a limitation on the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. An access node handover method, characterized by, The application discloses a mobility management controller applied to a medium earth orbit (MEO) satellite, and the MEO satellite communicates with a geosynchronous earth orbit (GEO) satellite. In response to a handover request initiated by a target low earth orbit (LEO) satellite, whether there is a candidate LEO satellite in the candidate LEO satellites is determined according to terminal position information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite and satellite communication information of the candidate LEO satellites; wherein the candidate LEO satellites are LEO satellites managed by the MEO satellite except the target LEO satellite, and candidate ground base stations are ground base stations managed by the MEO satellite; the satellite communication information comprises satellite position information and satellite communication resource information, and the base station communication information comprises base station position information and base station communication resource information; a predicted signal strength between the candidate LEO satellite and the target terminal is greater than a target strength threshold value; If the candidate LEO satellite exists, a target access node is selected from the candidate LEO satellite; if the candidate LEO satellite does not exist, a target access node is selected from the candidate ground base stations according to the terminal position information of the target terminal and the base station communication information of the candidate ground base stations; wherein a predicted signal strength between the target access node and the target terminal is greater than a target strength threshold value; The target terminal is controlled to disconnect the connection between the target terminal and the target LEO satellite, and the target terminal accesses the target access node through the target access node.

2. The method of claim 1, wherein, The determination whether there is a candidate LEO satellite in the candidate LEO satellites according to the terminal position information of the target terminal and the satellite communication information of the candidate LEO satellites comprises: According to the terminal position information of the target terminal and the satellite position information of the candidate LEO satellites, whether there is a first LEO satellite in the candidate LEO satellites is determined; wherein a communication distance between the first LEO satellite and the target terminal is less than a distance threshold value, and a predicted signal strength between the first LEO satellite and the target terminal is greater than a target strength threshold value; If the first LEO satellite exists, whether there is a second LEO satellite satisfying a communication requirement in the handover request in the first LEO satellite is determined according to satellite communication resource information of the first LEO satellite; If the second LEO satellite exists, the second LEO satellite is taken as a candidate LEO satellite, and it is determined that there is a candidate LEO satellite in the candidate LEO satellites.

3. The method according to any of claims 1-2, characterized in that, The control that the target terminal communicating with the target LEO satellite disconnects the connection between the target terminal and the target LEO satellite and accesses the target access node through the target access node comprises: In a case where 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 a communication resource satisfying the communication requirement in the handover request. In a case that the reservation completion response fed back by the target access node is acquired, a handover request response is sent to the target terminal through the target LEO satellite to instruct the target terminal to disconnect the connection between the target terminal and the target LEO satellite and access the target access node through the target access node.

4. The method of claim 3, wherein, The method further comprises: In a case that the reservation completion response fed back by the target access node is acquired and the actual signal strength between the target LEO satellite and the target terminal is determined to be less than the actual handover strength threshold, a handover request response is sent to the target terminal through the target LEO satellite.

5. The method of claim 4, wherein, The handover request is generated by the target LEO satellite in a case that the actual signal strength between the target LEO satellite and the target terminal is determined to reach 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.

6. The method of claim 1, wherein, The method further comprises: For each candidate LEO satellite, satellite position information of the candidate LEO satellite is predicted according to 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, the remaining service time and the number of idle channels of the candidate LEO satellite.

7. An access node handover apparatus, characterized by: A mobility management controller is configured in a medium earth orbit (MEO) satellite, the MEO satellite communicates with a geosynchronous earth orbit (GEO) satellite, and the device comprises: A response module is configured to, in response to a handover request initiated by a target LEO satellite, determine whether there is a candidate LEO satellite in the candidate LEO satellites according to terminal position information of a target terminal currently communicating with the target LEO satellite reported by a GEO satellite and satellite communication information of the candidate LEO satellites; if there is, select a target access node from the candidate LEO satellites; if not, select a target access node from candidate ground base stations according to the terminal position information of the target terminal and base station communication information of the candidate ground base stations. The candidate LEO satellites are LEO satellites managed by the MEO satellite except the target LEO satellite, and the candidate ground base stations are ground base stations managed by the MEO satellite; 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; the predicted signal strength between the candidate LEO satellite and the target terminal is greater than a target strength threshold; the predicted signal strength between the target access node and the target terminal is greater than the target strength threshold; An access control module is configured to control the target terminal to disconnect the connection between the target terminal and the target LEO satellite and access the target access node through the target access node.

8. A mobility management controller in a MEO satellite comprising a memory and a processor, said memory storing a computer program, characterized in that, The processor executes the computer program to implement the steps of the method in any one of claims 1 to 6. The processor executes the computer program to implement the steps of the method in any one of claims 1 to 6.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program, which when executed by a processor, implements the steps of the method of any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that, The computer program, which when executed by a processor, implements the steps of the method of any one of claims 1 to 6.

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