Satellite switching method and device, electronic equipment and storage medium

Abstract

The invention relates to the technical field of satellite communication, and provides a satellite switching method and device, electronic equipment and a storage medium, and the method comprises the steps: transmitting the region configuration information of a current region and a region adjacent to the current region to a user terminal based on the global region configuration information transmitted by a ground control center after the user terminal accesses a satellite; receiving a region measurement report reported by the user terminal, wherein the report comprises a current region identifier, a target region identifier and a predicted duration from the current region to the target region; the UE exchanges residual capacity information with a standby satellite in real time through an inter-satellite link, and generates a switching directed graph based on a received area measurement report and own orbit data, and the standby satellite refers to a satellite which can be switched to when the UE is connected to the current satellite; and determining a switching path by using the switching directed graph, and executing a switching process. According to the method, switching is carried out based on the switching directed graph, the overhead of the UE in the switching process can be reduced, and meanwhile the switching performance can be guaranteed.

Description

Technical Field

[0001] The present invention belongs to the field of satellite communication technology, and in particular, relates to a satellite switching method, device, electronic equipment and storage medium. Background Art

[0002] With the development of communication technology, satellite communications play an important role in the development and deployment of 6G networks. Low Earth Orbit satellite communications have received extensive attention and research worldwide. Compared with geostationary orbit satellites, low Earth orbit (LEO) satellites have a lower orbit altitude, lower communication latency, and higher data transmission rate. This makes low-orbit satellite communications very promising in providing global coverage, connecting remote areas, and ensuring emergency communications. However, low-orbit satellites have a small coverage area and move around the earth at a fast speed, requiring frequent switching of ground user equipment (UE). The high-speed movement of UE makes switching more frequent. Such frequent switching brings high switching overhead, which may lead to increased UE power consumption, shortened battery life, and increased signaling traffic, which then reduces the overall user experience. Therefore, how to reduce the overhead during switching becomes a challenge.

[0003] There are two existing solutions for ground equipment to switch between satellites.

[0004] The first one: a threshold-based satellite communication link switching scheme. This scheme first sets one or more signal strength thresholds as a benchmark for judging whether the current satellite connection is stable. In actual operation, ground equipment continuously monitors the signal strength of the currently connected satellite and other available satellites and regularly uploads measurement reports. When the signal strength drops below the preset threshold, the system triggers the switching mechanism. At this time, the source satellite sends a switching request to the control center and maintains the connection during this period. Once a reply message to the switching request is received, the source satellite immediately executes the switching process, transfers the UE's connection to the target satellite, disconnects the UE from the source satellite, and re-establishes a communication link with the new satellite.

[0005] The second type: user-centric switching scheme. This scheme is based on multi-objective optimization and takes into account the high-speed movement of ground users. It is user-centric and aims to optimize the process of user access to satellites by accurately predicting service time and reasonably allocating communication channel resources. First, the spatial relationship coupling model is used to predict the relative motion pattern between the user terminal and the satellite to determine the satellite service time that the user may receive in the future. At the same time, based on the periodic motion law of the satellite itself, the available channel estimation model is used to predict the available communication resources of adjacent satellites at future times, thereby effectively avoiding the problem of switching failure caused by channel congestion. The scheme uses reinforcement learning methods to comprehensively consider multiple switching factors, realize optimization decisions under multiple standards, and select the best access satellite for the user terminal. The user terminal sends a switching request to the selected access satellite, and then performs the necessary data synchronization and access procedures to establish a new communication session. After the session is successfully established, the user terminal will send a switching completion signal to the original service satellite and release the original resources to ensure the smoothness and efficiency of the entire switching process.

[0006] Disadvantages of the first solution: During the threshold-based switching process, the satellite's perception of the channel state depends on the precise measurements performed by the UE. This process requires the UE to continuously and frequently monitor the signal strength sent from different satellites. Subsequently, the UE needs to transmit these measurement data to the satellite securely and reliably via the uplink. Frequent signal detection and data transmission activities require the UE to have sufficient communication bandwidth, consume certain wireless resources, increase the UE's energy consumption, and bring a lot of overhead.

[0007] Disadvantages of the second solution: Frequent switching decisions and resource allocation will increase the signaling overhead of the system, especially in a user-dense or highly dynamically changing network environment. A large amount of prediction and optimization calculations may increase the signaling overhead and affect the performance and efficiency of the network.

[0008] In summary, the prior art has the defect that the UE has a large switching overhead between satellites. Summary of the invention

[0009] To solve the above problems, the present disclosure provides a satellite switching method, system, device, electronic device and storage medium, which adopts a switching solution based on area division and graph, which can reduce the UE overhead during the switching process and ensure the switching performance.

[0010] In a first aspect, a satellite switching method is provided, comprising:

[0011] Receive area configuration information of a current area and an adjacent area of ​​the current area sent by a current satellite, wherein the area configuration information includes: an area center position, an area radius, and an area identifier;

[0012] Generate a regional measurement report based on the received regional configuration information and in combination with the current position and the current speed, wherein the regional measurement report includes: the regional identifier of the current region, the regional identifier of the target region to be entered, and the estimated time required to enter the target region from the current region;

[0013] Report the generated regional measurement report to the current satellite so that the current satellite can make a switching decision;

[0014] Receiving radio resource control connection reconfiguration mobile control information sent by the current satellite, wherein the radio resource control connection reconfiguration mobile control information includes information of a target satellite to be switched to;

[0015] Accessing the target satellite using the target satellite information;

[0016] Send a radio resource control reconfiguration connection completion message to the target satellite.

[0017] Further, based on the received regional configuration information, combined with the current position and current speed, a regional measurement report is generated, including:

[0018] Using the center position of each area, calculate the distance from the current position to the center position of each area, and select the area where the center position of the area with the smallest distance is located as the current area; from the received area configuration information, use the center position of the current area to find the area identifier of the current area;

[0019] Assuming that the current motion is uniform linear motion, calculate the velocity component of the current velocity in the direction of the center position of each area; based on the velocity component, calculate the estimated time to enter the corresponding area respectively; select the area with the shortest estimated time as the target area; if the target area is inconsistent with the current area, and the estimated time is within the set range, it is determined that the target area is about to be entered; from the received area configuration information, use the area center position of the target area to find the area identifier of the target area;

[0020] The found area identifier of the current area, the area identifier of the target area, and the estimated time required to enter the target area from the current area are used as an area measurement report.

[0021] In a second aspect, a satellite switching method is provided, comprising:

[0022] After the user terminal accesses the satellite, based on the global area configuration information sent by the ground control center, the area configuration information of the current area and the adjacent areas of the current area is sent to the user terminal, wherein the area configuration information includes: the area center position, the area radius and the area identifier;

[0023] Receive the area measurement report reported by the user terminal, where the area measurement report includes: the area identifier of the current area, the area identifier of the target area, and the estimated duration required to enter the target area from the current area;

[0024] Through the inter-satellite link, exchange the remaining capacity information with the standby satellite in real time, and generate a handover directed graph based on the received area measurement report and its own orbit data, where the standby satellite refers to the satellite that can be switched to when the UE is connected to the current satellite;

[0025] Use the handover directed graph to determine the handover path;

[0026] Execute the handover process according to the handover path, and initiate a handover request to the target satellite on the handover path;

[0027] Receive the handover request reply returned after the target satellite completes the access authentication;

[0028] Send radio resource control connection reconfiguration mobility control information to the user terminal;

[0029] Send sequence number status transfer information to the target satellite;

[0030] Receive the user terminal context release notification from the target satellite;

[0031] Release the user terminal context.

[0032] Furthermore, the area radius is obtained by the ground control center dividing the earth's surface based on some or all of the access constraint, channel stability constraint, and handover frequency constraint.

[0033] Furthermore, the access constraint is: R a <R s , where R a represents the area radius, and R s represents the satellite coverage radius;

[0034] The channel stability constraint is: σ θ <thθ and σ PL <thPL, where θ is the elevation angle, σ θ is the standard deviation of the elevation angle, thθ is the standard deviation threshold of the elevation angle; PL is the path loss, σ PL is the standard deviation of the path loss, and thPL is the standard deviation threshold of the path loss;

[0035] The handover frequency constraint is: H(Ra) < h, where h is the handover frequency threshold, and H(.) is the functional relationship between the area radius and the handover frequency, which is determined based on simulation experiments.

[0036] Furthermore, the remaining capacity information is exchanged with the backup satellite in real time through the intersatellite link, and a switching directed graph is generated based on the received regional measurement report and its own orbit data, including:

[0037] The satellites that can cover the current area are taken as nodes, and the switching operations that can be performed between two satellites are regarded as edges. The weight of each edge is designed based on the available capacity of the backup satellite, the remaining service time of the current satellite for the current area calculated based on orbital data, and the cost of each switching action to generate a switching directed graph; wherein the switching cost includes the number of switching times, the overlapping time, and the average signal strength of the switching process, and the satellites that can cover the current area include the current satellite and the backup satellite.

[0038] Furthermore, the switching directed graph is used to determine the switching path, including:

[0039] Taking into account the path loss, satellite capacity and switching delay factors, the optimal switching path is calculated using the switching directed graph.

[0040] In a third aspect, a satellite switching device is provided, including: a first receiving unit, a measurement report generating unit, a reporting unit, a second receiving unit, an access unit and a sending unit; wherein:

[0041] A first receiving unit is used to receive area configuration information of a current area and an adjacent area of ​​the current area sent by a current satellite, wherein the area configuration information includes: an area center position, an area radius and an area identifier;

[0042] A measurement report generating unit, configured to generate a regional measurement report according to the received regional configuration information, in combination with the current position and the current speed, wherein the regional measurement report includes: an area identifier of the current area, an area identifier of the target area to be entered, and an estimated time required to enter the target area from the current area;

[0043] A reporting unit, used to report the generated regional measurement report to the current satellite, so that the current satellite can make a switching decision;

[0044] A second receiving unit is used to receive radio resource control connection reconfiguration mobile control information sent by the current satellite, wherein the radio resource control connection reconfiguration mobile control information includes information of a target satellite to be switched to;

[0045] An access unit, used to access the target satellite using the target satellite information;

[0046] The sending unit is used to send a radio resource control reconfiguration connection completion message to the target satellite.

[0047] In a fourth aspect, a satellite switching device is provided, comprising: a first sending unit, a first receiving unit, a directed graph generating unit, a switching unit, a second sending unit, a second receiving unit and a releasing unit; wherein:

[0048] The first sending unit is used to send the area configuration information of the current area and the adjacent area of ​​the current area to the user terminal based on the area configuration information of the current area and the adjacent area of ​​the current area sent by the ground control center after the user terminal accesses the satellite, and send the radio resource control connection reconfiguration mobile control information to the user terminal after receiving the handover request reply returned after the target satellite completes the access authentication; wherein the area configuration information includes: the area center position, the area radius and the area identifier;

[0049] A first receiving unit, configured to receive an area measurement report reported by a user terminal, wherein the area measurement report includes: an area identifier of a current area, an area identifier of a target area, and an estimated time required to enter the target area from the current area;

[0050] A directed graph generating unit is used to exchange remaining capacity information with a backup satellite in real time through an intersatellite link, and generate a switching directed graph based on a received regional measurement report and its own orbit data, wherein the backup satellite refers to a satellite that can be switched to when the UE is connected to the current satellite;

[0051] A switching unit, used to determine a switching path using a switching directed graph;

[0052] A second sending unit is used to execute the handover process according to the handover path, initiate a handover request to the target satellite on the handover path, and send sequence number state transfer information to the target satellite after the first sending unit sends the radio resource control connection reconfiguration mobility control information to the user terminal;

[0053] A second receiving unit is used to receive a handover request reply returned by the target satellite after completing access authentication, and receive a user terminal context release notification from the target satellite;

[0054] The releasing unit is used to release the user terminal context when the second receiving unit receives the user terminal context release notification from the target satellite.

[0055] In a fifth aspect, an electronic device is provided, comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;

[0056] Memory, used to store computer programs;

[0057] The processor is used to implement the steps of the above method when executing the program stored in the memory.

[0058] According to a sixth aspect, a computer storage medium is provided, wherein a computer program is stored in the computer storage medium, and the computer program implements the steps of the above method when executed by a processor.

[0059] Compared with the prior art, the present invention has the following advantages:

[0060] 1) This disclosure first proposes an Area-division and Graph based Handover (AGH) solution, which divides the earth's surface into multiple areas and simplifies the spatial relationship between the mobile UE and the mobile satellite through the areas: the UE moves within or between areas; the satellite calculates the handover sequence in the handover directed graph for different areas. This method can reduce the UE overhead during the handover process while ensuring the handover performance.

[0061] 2) The present invention designs a multi-constrained ground area division mechanism, calculates the distribution of path loss and elevation angle in each area, predicts the probability of UE crossing areas, ensures the consistency of the link between UE and satellite in a single area, and provides a basis for calculating the switching sequence.

[0062] 3) The present disclosure uses a directed graph-based method to make handover decisions based on satellite trajectories and UE regional measurement reports. The shortest path algorithm is used to consider the joint optimization of multiple performances during the handover process, and the subsequent handover sequence is calculated, further reducing the handover overhead.

[0063] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or be understood by implementing the present disclosure. The purpose and other advantages of the present disclosure can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0065] Figure 1 A schematic diagram of a satellite system switching interaction process according to an embodiment of the present disclosure is shown;

[0066] Figure 2 A flow chart of a satellite system switching method according to an embodiment of the present disclosure is shown;

[0067] Figure 3A schematic diagram of a single satellite covering a single area according to an embodiment of the present disclosure is shown;

[0068] Figure 4 A directed graph schematic diagram according to an embodiment of the present disclosure is shown;

[0069] Figure 5 A schematic structural diagram of an electronic device according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0070] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0071] Figure 1 A schematic diagram of a satellite system switching interaction process according to an embodiment of the present disclosure is shown. Figure 1 As shown, it includes UE, currently accessed satellite and multiple candidate satellites, one of which is the target satellite. UE is the subject of communication, and the satellite provides network services for UE. The satellite system switching method of the embodiment of the present disclosure is as follows Figure 2 As shown, the following steps are included:

[0072] Step 101: The ground control center of the satellite communication system divides the earth's surface into regions based on known satellite orbits and coverage areas, generates global regional configuration information, and sends the global regional configuration information to all satellites.

[0073] Since LEO satellites are constantly orbiting the Earth, the ground control center needs to send global regional configuration information to each satellite.

[0074] Specifically, the ground control center can perform regional division through a multi-constraint ground regional division mechanism.

[0075] The above multi-constraint ground area division mechanism aims to ensure that the status of the UE in a single area is consistent with the inter-satellite channel, and the number of inter-domain switching is controlled within a certain range so as not to affect the switching overhead.

[0076] The reasonable setting of the area size is crucial to the performance of the satellite communication system. It not only affects the number of satellites and the distribution of channels in the area, but also directly affects the frequency of UE crossing the area, which in turn has a significant impact on the switching performance. In order to ensure the quality of communication and service continuity, the first task is to scientifically determine the setting of the area size. In this process, multiple constraints need to be considered comprehensively, including access constraints, channel stability constraints, and some or all of the switching frequency constraints.

[0077] (1) Access constraints. To ensure the effective implementation of the communication solution, each satellite must ensure that it can fully cover the designated area, such as Figure 3 As shown in the figure, to deal with possible edge effects. If the area radius is too large, a single satellite cannot fully cover the entire area, which may result in users in the area being able to access different satellites, making the subsequent switching decision mechanism based on the directed graph ineffective. Therefore, the size of the area cannot be expanded indefinitely, and must be maintained within the effective coverage capacity of the satellite to ensure that all users in the area can stably access satellite signals. That is, R a <R s , where R a Represents the area radius, R s Indicates the satellite coverage radius.

[0078] (2) Channel stability constraint. It is mainly reflected by the standard deviation of channel conditions in the region. In this scenario, channel conditions are mainly measured by two key parameters: elevation angle and path loss. Path loss is not only directly affected by the communication distance, but also closely related to the elevation angle, which depends on the straight-line distance dis between the terminal and the satellite sub-satellite point. The distribution characteristics of dis in the region are determined by the region radius R a , and the distance d from the center of the region to the subsatellite point. Through theoretical analysis, the cumulative distribution function F of dis dis As shown in formula (1):

[0079]

[0080] in:

[0081]

[0082] Indicates the area of ​​the sector where dis is less than x during the calculation process.

[0083] Assume that the elevation angle θ = f(dis) and the path loss PL = g(dis), then the cumulative distribution functions of θ and PL are:

[0084]

[0085] According to Formula (1) and Formula (3), the cumulative probability distributions of the dis, θ, and PL parameters can be calculated, and thus their standard deviations σ can be calculated. dis , σ θ and σ PL .

[0086] To ensure the stability of the channel conditions within the region, the present disclosure sets thresholds for the elevation angle and the path loss variance, and requires that their standard deviations must be lower than this threshold, thereby indirectly restricting the upper limit of the region size. If the threshold is too large, it will lead to too large a difference in the channel states between different positions within the region, affecting the accuracy of subsequent handover decisions and reducing the user experience during the handover process. If the threshold is too small, it will lead to too small a region radius, increasing the frequency of inter-region handovers and reducing the handover performance. Therefore, the region radius needs to be restricted within a certain range.

[0087] In this solution, the standard deviation threshold for the elevation angle is set to thθ, and the standard deviation threshold for the path loss is set to thPL. Then the constraint conditions are σθ < thθ, σ PL < thPL. Here, the value range of thθ is 3 to 5°; the value range of thPL is 0.2 to 0.4 dB, and it can be 0.3 dB.

[0088] (3) Handover frequency constraint. It focuses on reducing system overhead and interruptions to the UE experience. When the UE exhibits cross-region behavior, handover decisions need to be made and the handover process needs to be executed, which will increase the number of handovers and may lead to a decline in communication performance. The probability of the UE crossing different regions is closely related to its moving speed and the size of the region. Theoretically, the larger the region radius, the lower the probability of the UE crossing regions, because a larger region reduces the possibility of the UE entering a new region. However, too large a region may also lead to an increase in the non-uniformity of the channel conditions, affecting the communication quality. Therefore, the region size cannot be too small to avoid frequent handovers, but it cannot be too large to maintain the relative stability of the channel conditions. The present disclosure determines the corresponding relationship H(R a ) between the handover frequency and the region radius size through multiple simulation experiments. The specific function can be:

[0089]

[0090] where p1, p2, p3, p4, q1, q2, q3, q4 are the fitting coefficients of the simulation experiment data.

[0091] Set a handover frequency threshold h, and require that the handover frequency H(Ra) < h, so as to obtain the value range of Ra. Among them, the value range of h is related to the moving speed of the UE, and the specific value range can be between 0.05 and 0.25.

[0092] Based on the above three constraints, the embodiment of the present disclosure can determine a reasonable area radius range. Within this range, the channel stability and switching frequency are comprehensively considered to select a radius value. Then the earth's surface is evenly divided into multiple areas of the same size, and the areas are arranged in a honeycomb manner. There is a certain overlap between the areas to ensure the performance during the cross-area switching process.

[0093] It should be noted that in actual situations, the above constraints are not static, but can be dynamically adjusted according to specific environmental conditions, such as weather conditions, geographical location, electromagnetic interference, etc., as well as communication requirements, such as data transmission rate, delay requirements, coverage, etc. This flexibility ensures that the switching directed graph generated using the divided areas can adapt to a variety of application scenarios and always maintain its efficiency and practicality.

[0094] The area division process comprehensively considers access constraints, channel stability constraints, and switching frequency constraints, providing an accurate data basis for subsequent cross-area detection and switching path optimization, effectively improving the efficiency and stability of switching.

[0095] After the regional division is completed, the satellite system can make switching decisions for each area, reducing system overhead while ensuring switching performance.

[0096] Step 102: After the UE accesses the current satellite, the current satellite sends the area configuration information of the current area and the areas adjacent to the current area to the UE based on the received area configuration information.

[0097] The current area here refers to the area where the UE is currently located.

[0098] The above area configuration information is used to guide the UE to detect whether it is about to cross the area.

[0099] Step 103: The UE generates an area measurement report according to the received area configuration information and its own current location and current speed information.

[0100] The regional measurement report includes: the regional identifier of the current region, the regional identifier of the target region to be entered, and the estimated time required to enter the target region from the current region; the estimated time reflects how long it is expected to enter the target region.

[0101] The process of generating a regional measurement report is as follows:

[0102] Using the center position of each area, calculate the distance from the current position to the center position of each area, and select the area where the center position of the area with the smallest distance is located as the current area; from the received area configuration information, use the center position of the current area to find the area identifier of the current area;

[0103] Assuming that the current motion is uniform linear motion, calculate the velocity component of the current velocity in the direction of the center position of each area; based on the velocity component, calculate the estimated time to enter the corresponding area respectively; select the area with the shortest estimated time as the target area; if the target area is inconsistent with the current area, and the estimated time is within the set range, it is determined that the target area is about to be entered; from the received area configuration information, use the area center position of the target area to find the area identifier of the target area;

[0104] The found area identifier of the current area, the area identifier of the target area, and the estimated time required to enter the target area from the current area are used as an area measurement report.

[0105] Specifically, when determining the current area identifier, the center Pa and the area radius Ra of the known area are used. u Calculate the distance d(a, u) from the UE to the center of these areas, select the area with the smallest distance as the current area, and store its area identifier. When calculating the target area identifier, the UE is considered to be moving in a uniform straight line at the moment of calculation, so the UE's speed v is calculated separately u The component v in the direction from UE to multiple area centers ua :

[0106]

[0107] Then according to this velocity component v ua Calculate the estimated time t for UE to enter the area ua :

[0108]

[0109] The area with the shortest estimated duration is selected as the target area. If the target area is not consistent with the current area, and the estimated duration is within a specific range (such as 0 to 3 seconds), it can be considered that the UE is about to cross the area and enter the target area.

[0110] This step 103 means that the UE can determine in real time whether a cross-region situation will occur, that is, a handover state, according to its own moving speed and location information combined with the region boundary.

[0111] In this step 103, when the UE senses the risk of cross-area handover, it reports the regional measurement report, which reduces the number of measurement report reports and saves signaling overhead compared to the existing measurement report reporting.

[0112] Step 104: The UE reports the generated regional measurement report to the current satellite, so that the current satellite can make a handover decision.

[0113] Compared with the traditional passive switching method, judging the switching status enables the UE to perceive the risk of cross-regional switching in advance and report the regional measurement report. The satellite that receives the measurement report will make switching decisions and switching preparations, providing more sufficient preparation time for the switching process, improving the efficiency of switching preparation, avoiding communication interruption caused by switching delays, significantly improving the timeliness of switching and user experience, and laying the foundation for subsequent switching path selection and decision execution.

[0114] Step 105: The current satellite exchanges remaining capacity information with the backup satellite in real time through the inter-satellite link, and generates a switching directed graph in combination with the UE's regional measurement report and its own orbit data.

[0115] The backup satellite refers to a satellite to which the UE can switch when it is connected to the current satellite.

[0116] Specifically, the satellite that can cover the current area is taken as a node, the switching operation that can be performed between two satellites is regarded as an edge, and the weight of each edge is designed based on the available capacity of the spare satellite, the remaining service time of the current satellite for the current area calculated based on its own orbital data, and the cost of each switching action to generate a switching directed graph, where the cost of each switching action includes the number of switching times, the overlapping time, and the average signal strength of the switching process. The satellites that can cover the current area include the current satellite and the spare satellite.

[0117] Specifically, the weight of each edge is obtained by weighted summing the number of handovers, normalized satellite capacity, normalized overlap time, and normalized average signal strength during the handover process. For example, assuming that the UE is currently connected to satellite S21, the satellites that can be switched to are S22, S11, and S32; after the UE is connected to S22, it can be connected to S23, S12, and S33. Based on the relationship between satellite visibility, the following can be generated: Figure 4 The directed graph shown.

[0118] The weight of the edge S21-S22 is obtained by weighted summing the number of switching times, the normalized capacity of satellite S22, the normalized overlap length of the visible time of S21 and S22, and the normalized average signal strength of S22.

[0119] Step 106: The current satellite uses the switching directed graph to determine the switching path;

[0120] Specifically, the current satellite calculates the optimal switching path by using a switching directed graph by comprehensively considering factors such as path loss, satellite capacity and switching delay.

[0121] The optimal switching path includes multiple switching target satellites and switching times within a period of time.

[0122] Within the region, based on the above constraints, it can be assumed that all UEs have similar availability to satellites, so only one handover directed graph needs to be used to calculate the handover sequence.

[0123] According to the weight of the edge, the shortest path algorithm is used to calculate the shortest path in the switching directed graph, that is, the switching sequence of UEs in the area. The UE can then perform the switching process in sequence according to the switching sequence. The area is designed to be circular, with overlapping distances between adjacent areas to ensure seamless coverage. When the UE enters one of the overlapping areas and its current direction of movement is towards a new area, it triggers a cross-area situation. It is worth noting that even if the UE moves to a new area, the satellite it is currently connected to may still provide service for a limited time. During this period, the satellite can complete the switching decision while ensuring that the service is not immediately interrupted.

[0124] Using the directed graph generated in step 105, with the satellite S21 where the UE is currently located as the starting point and all the satellites that the UE may access at the end of the session as the end points, an optimal switching path is found according to the weight of each edge using the shortest path algorithm to minimize the switching overhead while ensuring that the communication efficiency is not reduced during the switching process. For example, the calculated optimal switching path may be S21-S22-S23-S13.

[0125] The switching mechanism based on the directed graph described in step 106 intuitively displays and manages the switching relationship between each satellite by constructing a directed graph model with clear logic and structure. On this basis, the shortest path algorithm is used to efficiently calculate the optimal switching path from the current state to the target state, thereby greatly reducing the resource consumption and time cost in the switching decision process. The design of this solution is not limited to the use of a specific shortest path algorithm, but focuses on how to optimize the switching logic and reduce the overall overhead by using the characteristics of the directed graph. Therefore, under the premise of ensuring that the switching performance is maintained at an efficient and stable level, other similar algorithms can be flexibly adopted, or the existing algorithms can be improved and innovated to realize the function of switching decision.

[0126] This step 106 significantly improves the rationality and efficiency of the switching path through multi-factor optimization, ensures the service quality of the target satellite and the overall stability of the system. At the same time, a switching path includes multiple switching decisions, which is conducive to reducing the signaling overhead and computing overhead in the switching decision process.

[0127] Step 107: The current satellite executes the switching process according to the calculated switching path and initiates a switching request to the target satellite on the switching path.

[0128] Following the optimal handover path generated in step 106, the current satellite S21 initiates a handover request to the target satellite S22 after the UE accesses S21.

[0129] Step 108: After completing the access authentication, the target satellite returns a handover request reply to the current satellite.

[0130] The switching request reply here is information that switching to the target satellite can be performed.

[0131] Step 109: The current satellite sends Radio Resource Control (RRC) connection reconfiguration mobility control information to the UE.

[0132] The above RRC connection reconfiguration mobile control information includes information of the target satellite to be switched to.

[0133] Step 110: The current satellite sends a serial number (SN) state transfer message to the target satellite.

[0134] Step 111: The UE accesses the target satellite using the target satellite information to be switched to.

[0135] Step 112: The UE performs RRC reconfiguration and the connection is completed.

[0136] Step 113: The target satellite notifies the Access and Mobility Management Function (AMF).

[0137] Step 114: The target satellite notifies the current satellite to release the UE context.

[0138] At this point, the entire switching process is finally completed.

[0139] The above steps 107 to 114 avoid the risk of interruption during the switching process and reduce the switching delay through advance planning and rapid context transfer, thereby ensuring the efficiency and reliability of the switching and further improving the user experience and communication service quality.

[0140] The present disclosure proposes an inter-satellite switching method based on region division and directed graph. Compared with the existing switching methods, the present disclosure has the following advantages: In the traditional method, the switching decision needs to be calculated based on the frequently sent measurement reports, and the link status between the UE and the satellite also needs to be predicted by the UE. This process increases the UE overhead. In the AGH, the concept of region is introduced, and the spatial relationship between the UE and the region is convenient for measurement, and the link status between the region and the satellite is also convenient for the satellite to predict. This mechanism reduces the signaling interaction between the UE and the satellite, and directly reduces the overhead in the switching process. The multi-constraint ground region division mechanism designed by the present disclosure can ensure that the status of the UE and the satellite channel in a single area is consistent, and the number of inter-domain switching is controlled within a certain range, so that it will not affect the switching overhead. In addition, the AGH adopts a switching decision mechanism based on a directed graph, which directly calculates a complete switching sequence for the UE, reduces the signaling interaction required for subsequent decisions, and further reduces the overhead.

[0141] Based on the same inventive concept as the above disclosed content, the present disclosure also provides a satellite switching device, including: a first receiving unit, a measurement report generating unit, a reporting unit, a second receiving unit, an access unit and a sending unit; wherein:

[0142] A first receiving unit is used to receive area configuration information of a current area and an adjacent area of ​​the current area sent by a current satellite, wherein the area configuration information includes: an area center position, an area radius and an area identifier;

[0143] A measurement report generating unit, configured to generate a regional measurement report according to the received regional configuration information, in combination with the current position and the current speed, wherein the regional measurement report includes: an area identifier of the current area, an area identifier of the target area to be entered, and an estimated time required to enter the target area from the current area;

[0144] A reporting unit, used to report the generated regional measurement report to the current satellite, so that the current satellite can make a switching decision;

[0145] A second receiving unit is used to receive radio resource control connection reconfiguration mobile control information sent by the current satellite, wherein the radio resource control connection reconfiguration mobile control information includes information of a target satellite to be switched to;

[0146] An access unit, used to access the target satellite using the target satellite information;

[0147] The sending unit is used to send a radio resource control reconfiguration connection completion message to the target satellite.

[0148] Based on the same inventive concept as the above disclosed content, the present disclosure also provides a satellite switching device, including: a first sending unit, a first receiving unit, a directed graph generating unit, a switching unit, a second sending unit, a second receiving unit and a releasing unit; wherein:

[0149] The first sending unit is used to send the regional configuration information of the current area and the adjacent area of ​​the current area to the user terminal based on the global regional configuration information sent by the ground control center after the user terminal accesses the satellite, and send the radio resource control connection reconfiguration mobile control information to the user terminal after receiving the handover request reply returned after the target satellite completes the access authentication; wherein the regional configuration information includes: the regional center position, the regional radius and the regional identifier;

[0150] A first receiving unit, configured to receive an area measurement report reported by a user terminal, wherein the area measurement report includes: an area identifier of a current area, an area identifier of a target area, and an estimated time required to enter the target area from the current area;

[0151] A directed graph generation unit, used to exchange remaining capacity information with the backup satellite in real time through an intersatellite link, and generate a switching directed graph based on the received regional measurement report and its own orbit data;

[0152] A switching unit, used to determine a switching path using a switching directed graph;

[0153] A second sending unit is used to execute the handover process according to the handover path, initiate a handover request to the target satellite on the handover path, and send sequence number state transfer information to the target satellite after the first sending unit sends the radio resource control connection reconfiguration mobility control information to the user terminal;

[0154] A second receiving unit is used to receive a handover request reply returned by the target satellite after completing access authentication, and receive a user terminal context release notification from the target satellite;

[0155] The releasing unit is used to release the user terminal context when the second receiving unit receives the user terminal context release notification from the target satellite.

[0156] Based on the same inventive concept as the above disclosed content, the present disclosure also provides an electronic device, whose structural schematic diagram is as follows: Figure 5 The electronic device of the embodiment of the present disclosure includes at least one processor and at least one memory electrically connected to each other, wherein the memory is electrically connected to the processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method as described above.

[0157] It should be noted that the electrical connection between the above-mentioned units does not necessarily mean the connection between lines. An indirect connection method can be applied to the embodiments of the present disclosure as long as the purpose of the present disclosure is achieved.

[0158] Based on the same inventive concept, the present disclosure also provides a computer storage medium, in which a computer program is stored. When the computer program is executed by a processor, the steps of the above method are implemented.

[0159] Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A satellite switching method, characterized in that: include: Receive area configuration information of a current area and an adjacent area of ​​the current area sent by a current satellite, wherein the area configuration information includes: an area center position, an area radius, and an area identifier; Generate a regional measurement report based on the received regional configuration information and in combination with the current position and the current speed, wherein the regional measurement report includes: the regional identifier of the current region, the regional identifier of the target region to be entered, and the estimated time required to enter the target region from the current region; Report the generated regional measurement report to the current satellite so that the current satellite can make a switching decision; Receiving radio resource control connection reconfiguration mobile control information sent by a current satellite, wherein the radio resource control connection reconfiguration mobile control information includes information of a target satellite to be switched to; Accessing the target satellite using the target satellite information; Send a radio resource control reconfiguration connection completion message to the target satellite.

2. The method according to claim 1, characterized in that Based on the received regional configuration information, combined with the current position and current speed, a regional measurement report is generated, including: Using the center position of each area, calculate the distance from the current position to the center position of each area, and select the area where the center position of the area with the smallest distance is located as the current area; from the received area configuration information, use the center position of the current area to find the area identifier of the current area; Assuming that the current motion is uniform linear motion, calculate the velocity component of the current velocity in the direction of the center position of each area; based on the velocity component, calculate the estimated time to enter the corresponding area respectively; select the area with the shortest estimated time as the target area; if the target area is inconsistent with the current area, and the estimated time is within the set range, it is determined that the target area is about to be entered; from the received area configuration information, use the area center position of the target area to find the area identifier of the target area; The found area identifier of the current area, the area identifier of the target area, and the estimated time required to enter the target area from the current area are used as an area measurement report.

3. A satellite switching method, characterized in that: include: After the user terminal accesses the satellite, based on the global area configuration information sent by the ground control center, the area configuration information of the current area and the adjacent areas of the current area is sent to the user terminal, wherein the area configuration information includes: the area center position, the area radius and the area identifier; Receiving an area measurement report reported by a user terminal, wherein the area measurement report includes: an area identifier of a current area, an area identifier of a target area, and an estimated time required to enter the target area from the current area; Exchange remaining capacity information with backup satellites in real time through intersatellite links, and generate a switching directed graph based on received regional measurement reports and its own orbital data, where the backup satellite refers to the satellite that can be switched to when the UE is connected to the current satellite; Using the switching directed graph, determine the switching path; According to the switching path, the switching process is executed, and a switching request is initiated to the target satellite on the switching path; Receive a handover request reply returned by the target satellite after completing access authentication; Sending radio resource control connection reconfiguration mobility control information to the user terminal; Sending sequence number status transfer information to the target satellite; Receiving a user terminal context release notification from a target satellite; Release the user terminal context.

4. The method according to claim 3, characterized in that The area radius is obtained by the ground control center dividing the earth's surface based on some or all of the access constraint, channel stability constraint, and handover frequency constraint.

5. The method according to claim 4, characterized in that The access constraint is: R a <R s , where R a Represents the area radius, R s Indicates the satellite coverage radius; The channel stability constraint is: σ θ < thθ and σ PL < thPL, where θ is the elevation angle, σ θ is the standard deviation of the elevation angle, thθ is the standard deviation threshold of the elevation angle; PL is the path loss, σ PL is the standard deviation of the path loss, thPL is the standard deviation threshold of the path loss; The handover frequency constraint is: H(Ra) < h, where h is the handover frequency threshold, and H(.) is the functional relationship between the area radius and the handover frequency, determined based on simulation experiments.

6. The method according to any one of claims 3 to 5, characterized in that: Through the inter-satellite link, exchange the remaining capacity information with the standby satellite in real time, and generate a handover directed graph based on the received area measurement report and its own orbital data, including: Use the satellites that can cover the current area as nodes, and the handover operations that can be performed between two satellites are regarded as edges. Design the weight of each edge with the available capacity of the standby satellite, the remaining service time of the current satellite for the current area calculated based on the orbital data, and the cost of each handover action. Generate a handover directed graph; where the handover cost includes the number of handovers, the overlapping time, and the average signal strength during the handover process. The satellites that can cover the current area include the current satellite and the standby satellite.

7. The method according to any one of claims 3 to 5, characterized in that: Use the handover directed graph to determine the handover path, including: Comprehensively consider factors such as path loss, satellite capacity, and handover delay, and use the handover directed graph to calculate the optimal handover path.

8. A satellite switching device, characterized in that: Include: The first receiving unit, measurement report generation unit, reporting unit, second receiving unit, access unit, and sending unit; where: The first receiving unit is used to receive the area configuration information of the current area and the adjacent areas of the current area sent by the current satellite. The area configuration information includes: the area center position, area radius, and area identifier. The measurement report generation unit is used to generate an area measurement report according to the received area configuration information, combined with the current position and current speed. The area measurement report includes: the area identifier of the current area, the area identifier of the target area to be entered, and the estimated time required to enter the target area from the current area. The reporting unit is used to report the generated area measurement report to the current satellite for the current satellite to make a handover decision. The second receiving unit is used to receive the radio resource control connection reconfiguration mobility control information sent by the current satellite. The radio resource control connection reconfiguration mobility control information contains the target satellite information to be handed over to. The access unit is used to access the target satellite using the target satellite information. The sending unit is used to send a radio resource control reconfiguration connection completion message to the target satellite.

9. A satellite switching device, characterized in that: Include: The first sending unit, first receiving unit, directed graph generation unit, handover unit, second sending unit, second receiving unit, and release unit; where: The first sending unit, after the user terminal accesses the satellite, is used to send the area configuration information of the current area and the adjacent areas of the current area to the user terminal based on the global area configuration information sent by the ground control center, and to send the radio resource control connection reconfiguration mobility control information to the user terminal after receiving the handover request reply returned after the target satellite completes the access authentication; where the area configuration information includes: the area center position, area radius, and area identifier. A first receiving unit, configured to receive an area measurement report reported by a user terminal, wherein the area measurement report includes: an area identifier of a current area, an area identifier of a target area, and an estimated time required to enter the target area from the current area; A directed graph generating unit is used to exchange remaining capacity information with a backup satellite in real time through an intersatellite link, and generate a switching directed graph based on a received regional measurement report and its own orbit data, wherein the backup satellite refers to a satellite that can be switched to when the UE is connected to the current satellite; A switching unit, used to determine a switching path using a switching directed graph; A second sending unit is used to execute the handover process according to the handover path, initiate a handover request to the target satellite on the handover path, and send sequence number state transfer information to the target satellite after the first sending unit sends the radio resource control connection reconfiguration mobility control information to the user terminal; A second receiving unit is used to receive a handover request reply returned by the target satellite after completing access authentication, and receive a user terminal context release notification from the target satellite; The releasing unit is used to release the user terminal context when the second receiving unit receives the user terminal context release notification from the target satellite.

10. An electronic device, characterized in that: It includes a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; Memory, used to store computer programs; A processor, for implementing the steps of any method described in claims 1-7 when executing a program stored in a memory.

11. A computer storage medium, characterized in that: The computer storage medium stores a computer program, and when the computer program is executed by a processor, the steps of any method of claims 1-7 are implemented.

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