Processing method and system for inter-satellite switching of satellite-borne core network access mobility management function unit

Abstract

The invention discloses an inter-satellite switching processing method and system for accessing a mobility management function unit to a satellite-borne core network, and the method comprises the steps: carrying out the switching prediction based on a satellite orbit parameter, and determining an optimal switching time window in advance; the pre-synchronization of the user state is carried out through the inter-satellite link, and the state consistency in the switching process is ensured; and a staged switching process is adopted, so that rapid reconstruction of user services is realized. According to the method, the service interruption time in the satellite switching process can be remarkably shortened, the reliability of state synchronization is improved, the problems of large time delay, inaccurate prediction and unreliable state synchronization are effectively solved, and more stable and continuous service experience is provided for users in a low-orbit satellite communication network.

Description

Technical Field

[0001] The present invention relates to the field of satellite communication technology, and in particular to a processing method and system for inter-satellite handover of a satellite-borne core network access mobility management function unit. Background Art

[0002] With the rapid development of low-orbit satellite communication technology, mobile communication networks based on LEO (Low Earth Orbit) satellites are becoming an important part of future communication systems. Due to the high-speed movement of satellites, when users need to switch between different satellites, the traditional core network switching solution has the following problems: First, the core network functions in the existing technology are mainly deployed on the ground, resulting in the need to transfer through the ground core network during the satellite switching process, causing a large transmission delay; second, the existing switching solution lacks sufficient consideration of the characteristics of the satellite orbit and cannot accurately predict the best switching time; third, during the switching process, the transmission and synchronization mechanism of the user context state is not perfect, which easily leads to service interruption or inconsistent state. These problems seriously affect the business continuity of users during the satellite switching process.

[0003] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0004] The main purpose of the present invention is to provide a processing method and system for inter-satellite switching of a satellite-borne core network access mobility management functional unit, aiming to solve the problem in the prior art that when a user needs to switch between different satellites, transmission delay, inaccurate prediction of the optimal switching timing, and imperfect transmission and synchronization mechanisms affect the service continuity of the user during the satellite switching process.

[0005] To achieve the above object, the present invention provides a method for processing inter-satellite handover of a satellite-borne core network access mobility management function unit, and the method for processing inter-satellite handover of a satellite-borne core network access mobility management function unit comprises the following steps:

[0006] The source satellite RAN obtains satellite orbit parameters and reports them to the source satellite AMF. The source satellite AMF calculates the service overlap area with the target satellite based on the satellite orbit parameters and evaluates the optimal switching time window of the mobile user UE in the service overlap area.

[0007] The source satellite AMF obtains complete UE context information, sends a handover pre-notification to the target satellite AMF according to the UE context information, and the target satellite AMF reserves a preset storage space and performs resource evaluation;

[0008] The source satellite AMF locks the UE status data and transmits it to the target satellite AMF. The target satellite AMF stores the UE status data and performs data integrity verification;

[0009] When entering the optimal switching time window, the source satellite AMF sends a switching command to the source satellite RAN, the source satellite RAN sends a switching instruction to the mobile user UE, the mobile user UE initiates an access request to the target satellite RAN, and the target satellite RAN notifies the target satellite AMF that the switching event has started;

[0010] The target satellite AMF reads the UE status data, reconstructs the user plane bearer based on the UE status data, and the mobile user UE confirms that the user plane bearer is successfully reconstructed;

[0011] When the handover is completed, the target satellite AMF sends a confirmation notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite, and the source satellite AMF clears the UE status data.

[0012] Optionally, the processing method for inter-satellite handover of the satellite-borne core network access mobility management function unit, wherein the source satellite RAN obtains satellite orbit parameters and reports them to the source satellite AMF, and the source satellite AMF calculates the service overlap area with the target satellite according to the satellite orbit parameters, and evaluates the optimal switching time window of the mobile user UE in the service overlap area, specifically includes:

[0013] The source satellite RAN calculates and obtains satellite orbit parameters in real time, and reports the satellite orbit parameters to the source satellite AMF;

[0014] The source satellite AMF calculates the service overlap area with the target satellite based on the satellite orbit parameters and in combination with the satellite movement speed and coverage range;

[0015] The source satellite AMF evaluates the optimal switching time window for the mobile user UE in the service overlap area to ensure that the switching occurs at the time when the signal quality is optimal.

[0016] Optionally, the processing method for inter-satellite handover of the satellite-borne core network access mobility management function unit, wherein the source satellite AMF obtains complete UE context information, sends a handover pre-notification to the target satellite AMF according to the UE context information, and the target satellite AMF reserves a preset storage space and performs resource evaluation, specifically including:

[0017] After determining the optimal switching time window, the source satellite AMF obtains complete UE context information from the local source state database;

[0018] The source satellite AMF sends a handover pre-notification to the target satellite AMF, where the handover pre-notification includes an estimated handover time and context data size;

[0019] After receiving the switching pre-notification, the target satellite AMF reserves a preset storage space in the local target state database and performs resource evaluation to ensure support for the upcoming user session.

[0020] Optionally, in the method for processing inter-satellite switching of the satellite core network access mobility management functional unit, the UE context information includes authentication status, QoS configuration and session information.

[0021] Optionally, the processing method for inter-satellite handover of the satellite-borne core network access mobility management function unit, wherein the source satellite AMF locks the UE status data and transmits it to the target satellite AMF, the target satellite AMF stores the UE status data, and performs data integrity verification, specifically comprising:

[0022] The source satellite AMF locks the UE status data in the local source status database;

[0023] The source satellite AMF transmits the complete UE status data to the target satellite AMF via the inter-satellite link;

[0024] After receiving the complete UE status data, the target satellite AMF stores it in the local target status database and performs data integrity verification.

[0025] Optionally, the processing method for inter-satellite handover of the satellite-borne core network access mobility management function unit, wherein when entering the optimal handover time window, the source satellite AMF sends a handover command to the source satellite RAN, the source satellite RAN sends a handover instruction to the mobile user UE, the mobile user UE initiates an access request to the target satellite RAN, and the target satellite RAN notifies the target satellite AMF that the handover event has started, specifically includes:

[0026] When the predetermined optimal switching time window is reached, the source satellite AMF sends a switching command to the source satellite RAN, triggering the air interface switching process;

[0027] The source satellite RAN sends a handover instruction to the mobile user UE, wherein the handover instruction includes access parameters of the target satellite;

[0028] The mobile user UE initiates an access request to the target satellite RAN according to the access parameters of the target satellite;

[0029] After receiving the access request from the mobile user UE, the target satellite RAN notifies the target satellite AMF that the switching event has started.

[0030] Optionally, the processing method for inter-satellite handover of the satellite-borne core network access mobility management function unit, wherein the target satellite AMF reads UE status data, reconstructs the user plane bearer based on the UE status data, and the mobile user UE confirms that the user plane bearer reconstruction is successful, specifically includes:

[0031] The target satellite AMF reads the synchronized UE status data from the local target status database and rebuilds the user plane bearer based on the UE status data;

[0032] The mobile user UE confirms that the user plane bearer is reestablished successfully to ensure normal service.

[0033] Optionally, in the method for processing inter-satellite switching of the satellite core network access mobility management function unit, the process of reconstructing the user plane bearer includes restoring QoS configuration, reconstructing PDU session and allocating network resources.

[0034] Optionally, the processing method for inter-satellite handover of the satellite-borne core network access mobility management function unit, wherein, after the handover is completed, the target satellite AMF sends a confirmation notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite, and the source satellite AMF clears the UE status data, specifically including:

[0035] When the handover is completed, the target satellite AMF sends a confirmation handover completion notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite;

[0036] The source satellite AMF cleans up the UE status data in the local source status database and releases related resources;

[0037] When the local source status database confirms to the source satellite AMF after completing the cleanup, the source satellite AMF notifies the target satellite AMF that the entire switching process has ended.

[0038] In addition, to achieve the above-mentioned purpose, the present invention also provides a processing system for inter-satellite handover of a satellite-borne core network access mobility management function unit, wherein the processing system for inter-satellite handover of a satellite-borne core network access mobility management function unit comprises: a source satellite RAN, a source satellite AMF, a local source state database, a mobile user UE, a target satellite AMF, a local target state database and a target satellite RAN;

[0039] The source satellite RAN obtains satellite orbit parameters and reports them to the source satellite AMF. The source satellite AMF calculates the service overlap area with the target satellite based on the satellite orbit parameters and evaluates the optimal switching time window of the mobile user UE in the service overlap area.

[0040] The source satellite AMF obtains complete UE context information, sends a handover pre-notification to the target satellite AMF according to the UE context information, and the target satellite AMF reserves a preset storage space and performs resource evaluation;

[0041] The source satellite AMF locks the UE status data and transmits it to the target satellite AMF. The target satellite AMF stores the UE status data and performs data integrity verification;

[0042] When entering the optimal switching time window, the source satellite AMF sends a switching command to the source satellite RAN, the source satellite RAN sends a switching instruction to the mobile user UE, the mobile user UE initiates an access request to the target satellite RAN, and the target satellite RAN notifies the target satellite AMF that the switching event has started;

[0043] The target satellite AMF reads the UE status data, reconstructs the user plane bearer based on the UE status data, and the mobile user UE confirms that the user plane bearer is successfully reconstructed;

[0044] When the handover is completed, the target satellite AMF sends a confirmation notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite, and the source satellite AMF clears the UE status data.

[0045] In the present invention, the source satellite RAN obtains satellite orbit parameters and reports them to the source satellite AMF. The source satellite AMF calculates the service overlap area with the target satellite according to the satellite orbit parameters, and evaluates the optimal switching time window of the mobile user UE in the service overlap area; the source satellite AMF obtains complete UE context information, sends a switching pre-notification to the target satellite AMF according to the UE context information, the target satellite AMF reserves a preset storage space, and performs resource evaluation; the source satellite AMF locks the UE status data and transmits it to the target satellite AMF, the target satellite AMF stores the UE status data, and performs data integrity verification; when entering the optimal switching time window, the source satellite AMF sends a switching command to the source satellite RAN, the source satellite RAN sends a switching instruction to the mobile user UE, the mobile user UE initiates an access request to the target satellite RAN, and the target satellite RAN notifies the target satellite AMF that the switching event has started; the target satellite AMF reads the UE status data, rebuilds the user plane bearer based on the UE status data, and the mobile user UE confirms that the user plane bearer is successfully rebuilt; when the switching is completed, the target satellite AMF sends a confirmation notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite, and the source satellite AMF clears the UE status data. The present invention can significantly reduce the service interruption time during satellite switching, improve the reliability of state synchronization, effectively solve the problems of large delay, inaccurate prediction, and unreliable state synchronization, and provide users in low-orbit satellite communication networks with a more stable and continuous service experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the system architecture of the present invention for the switching scenario of the AMF network element of the low-orbit satellite onboard core network;

[0047] Figure 2It is a preferred embodiment of the method for processing inter-satellite handover of a satellite-borne core network access mobility management function unit of the present invention;

[0048] Figure 3 It is a schematic diagram of the entire principle process of the satellite-borne AMF switching implementation flow in a preferred embodiment of the processing method for inter-satellite switching of the satellite-borne core network access mobility management function unit of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] like Figure 1 As shown in the figure, the handover scenario of the AMF network element for the low-orbit satellite onboard core network consists of three main parts: the LEO satellite group, the ground facilities and the mobile user terminal UE (User Equipment). In the LEO satellite group, there are source satellites (Satellite 1) and target satellites (Satellite 2). Each satellite is equipped with a complete 5G core network functional unit, including AMF (Access and Mobility Management Function), SMF (Session Management Function), UPF (User Plane Function) and state database (i.e., Satellite 1-State Database 1 of the onboard core network and Satellite 2-State Database 2 of the onboard core network), where the state database is specifically used to store and manage UE context information. The two satellites are connected through the inter-satellite link to achieve state synchronization and control signaling interaction between AMFs. The ground facilities include ground stations, operation and maintenance management systems and ground core networks. The ground station is connected to the satellite through a backhaul link and is responsible for the transmission of signaling and data; the operation and maintenance management system manages and controls the satellite; and the ground core network serves as the central control node of the entire system. For mobile users (UE), the architecture shows the process of accessing the source satellite at time t1 and switching to the target satellite at time t2, indicating the AMF migration path of the UE during the satellite coverage switching process. The core of the entire architecture is to achieve business continuity guarantee for UE during satellite switching through a distributed satellite core network and an efficient state synchronization mechanism.

[0051] The processing method for inter-satellite handover of a satellite-borne core network access mobility management function unit described in a preferred embodiment of the present invention is as follows: Figure 2 and Figure 3 As shown, the processing method for inter-satellite handover of the satellite core network access mobility management function unit includes the following steps:

[0052] Step S10: The source satellite RAN obtains satellite orbit parameters and reports them to the source satellite AMF. The source satellite AMF calculates the service overlap area with the target satellite based on the satellite orbit parameters and evaluates the optimal switching time window of the mobile user UE within the service overlap area.

[0053] Specifically, in the orbit prediction and switching triggering phase: the source satellite RAN (Radio Access Network) calculates and obtains satellite orbit parameters in real time, and reports the satellite orbit parameters to the source satellite AMF (i.e. Figure 1 AMF1 in the source satellite); the source satellite AMF calculates the service overlap area with the target satellite based on the satellite orbit parameters and combined with the satellite movement speed and coverage range; at the same time, the source satellite AMF evaluates the optimal switching time window of the mobile user UE in the service overlap area to ensure that the switching occurs at the time of optimal signal quality.

[0054] The key to this stage is to accurately predict the switching timing and avoid signal blind spots.

[0055] Step S20: The source satellite AMF obtains complete UE context information, and sends a switching pre-notification to the target satellite AMF according to the UE context information. The target satellite AMF reserves a preset storage space and performs resource evaluation.

[0056] Specifically, in the pre-switching preparation phase: after determining the optimal switching time window, the source satellite AMF obtains complete UE context information from the local source state database; the UE context information includes authentication status, QoS configuration and session information, etc.; then the source satellite AMF sends a request to the target satellite AMF (i.e. Figure 1 The target satellite AMF receives the handover pre-notification and sends a handover pre-notification to the local target state database (DB2, i.e. Figure 1 A preset storage space is reserved in the state database 2) in the process and a resource assessment is performed to ensure support for the upcoming user session.

[0057] The focus of this stage is to prepare in advance and reduce the delay during switching.

[0058] Step S30: The source satellite AMF locks the UE status data and transmits it to the target satellite AMF. The target satellite AMF stores the UE status data and performs a data integrity check.

[0059] Specifically, in the state synchronization phase: to ensure state consistency, the source satellite AMF will store the local source state database (DB1, i.e. Figure 1The UE status data in the status database 1) is locked to prevent the data from changing during transmission; then, the source satellite AMF transmits the complete UE status data to the target satellite AMF through the inter-satellite link; after receiving the complete UE status data, the target satellite AMF stores it in the local target status database and performs data integrity verification.

[0060] After storage is completed, the reliability of state synchronization is ensured through a two-way confirmation mechanism. The core of this stage is to ensure the consistency and integrity of state data.

[0061] Step S40: When entering the optimal switching time window, the source satellite AMF sends a switching command to the source satellite RAN, the source satellite RAN sends a switching instruction to the mobile user UE, the mobile user UE initiates an access request to the target satellite RAN, and the target satellite RAN notifies the target satellite AMF that the switching event has started.

[0062] Specifically, in the switching execution phase: when entering the predetermined optimal switching time window, the source satellite AMF sends a switching command to the source satellite RAN, triggering the air interface switching process; the source satellite RAN sends a switching instruction to the mobile user UE, and the switching instruction includes the access parameters of the target satellite; the mobile user UE initiates an access request to the target satellite RAN according to the access parameters of the target satellite; after receiving the access request from the mobile user UE, the target satellite RAN notifies the target satellite AMF that the switching event has started.

[0063] At this stage, air interface switching needs to be completed quickly and accurately to minimize service interruption time.

[0064] Step S50: The target satellite AMF reads the UE status data, reconstructs the user plane bearer based on the UE status data, and the mobile user UE confirms that the user plane bearer is reconstructed successfully.

[0065] Specifically, in the service reconstruction phase: the target satellite AMF reads the synchronized UE status data from the local target status database, and rebuilds the user plane bearer based on the UE status data; the process of rebuilding the user plane bearer includes restoring QoS configuration, rebuilding PDU session and allocating network resources, etc.; the mobile user UE confirms that the user plane bearer reconstruction is successful to ensure the normal operation of the service.

[0066] The focus of this phase is to quickly restore business connections and ensure service quality.

[0067] Step S60: When the handover is completed, the target satellite AMF sends a confirmation notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite, and the source satellite AMF clears the UE status data.

[0068] Specifically, completion and cleanup phase: when the handover is completed, the target satellite AMF sends a confirmation handover completion notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite; the source satellite AMF cleans up the UE status data in the local source status database and releases related resources; when the local source status database confirms to the source satellite AMF after the cleanup is completed, the source satellite AMF notifies the target satellite AMF that the entire handover process has ended.

[0069] At this stage, it is necessary to ensure that resources are released in a timely manner to avoid residual status.

[0070] The present invention realizes the on-board distributed deployment of core network functions by deploying complete 5G core network functional units on LEO satellites, including AMF, SMF, UPF and a special state database. The method first predicts switching based on satellite orbit parameters to determine the optimal switching time window in advance; then pre-synchronizes the user status through the inter-satellite link to ensure the state consistency during the switching process; finally, a phased switching process is adopted to achieve rapid reconstruction of user services. The technical solution of the present invention can significantly reduce the service interruption time during satellite switching, improve the reliability of state synchronization, and effectively solve the problems of large delay, inaccurate prediction, unreliable state synchronization, etc. in the prior art, providing users in low-orbit satellite communication networks with a more stable and continuous service experience.

[0071] Furthermore, if Figure 3 As shown, based on the above-mentioned processing method for inter-satellite switching of satellite core network access mobility management functional unit, the present invention also provides a processing system for inter-satellite switching of satellite core network access mobility management functional unit, wherein the processing system for inter-satellite switching of satellite core network access mobility management functional unit includes: source satellite RAN, source satellite AMF, local source status database, mobile user UE, target satellite AMF, local target status database and target satellite RAN.

[0072] Specifically, the source satellite RAN obtains satellite orbit parameters and reports them to the source satellite AMF. The source satellite AMF calculates the service overlap area with the target satellite according to the satellite orbit parameters, and evaluates the optimal switching time window of the mobile user UE in the service overlap area; the source satellite AMF obtains complete UE context information, sends a switching pre-notification to the target satellite AMF according to the UE context information, the target satellite AMF reserves a preset storage space, and performs resource evaluation; the source satellite AMF locks the UE status data and transmits it to the target satellite AMF, the target satellite AMF stores the UE status data, and performs data integrity verification; when entering the optimal switching time window, the source satellite AMF sends a switching command to the source satellite RAN, the source satellite RAN sends a switching instruction to the mobile user UE, the mobile user UE initiates an access request to the target satellite RAN, and the target satellite RAN notifies the target satellite AMF that the switching event has started; the target satellite AMF reads the UE status data, rebuilds the user plane bearer based on the UE status data, and the mobile user UE confirms that the user plane bearer reconstruction is successful; when the switching is completed, the target satellite AMF sends a confirmation notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite, and the source satellite AMF clears the UE status data.

[0073] In summary, the present invention provides a method and system for processing inter-satellite handover of a satellite-borne core network access mobility management function unit, the method comprising: a source satellite RAN acquires satellite orbit parameters and reports them to a source satellite AMF, the source satellite AMF calculates a service overlap area with a target satellite according to the satellite orbit parameters, and evaluates an optimal handover time window of a mobile user UE in the service overlap area; the source satellite AMF acquires complete UE context information, sends a handover pre-notification to a target satellite AMF according to the UE context information, the target satellite AMF reserves a preset storage space, and performs resource evaluation; the source satellite AMF locks UE status data and transmits it to the target satellite AMF, the target The satellite AMF stores UE status data and performs data integrity verification; when entering the optimal switching time window, the source satellite AMF sends a switching command to the source satellite RAN, the source satellite RAN sends a switching instruction to the mobile user UE, the mobile user UE initiates an access request to the target satellite RAN, and the target satellite RAN notifies the target satellite AMF that the switching event has started; the target satellite AMF reads the UE status data, rebuilds the user plane bearer based on the UE status data, and the mobile user UE confirms that the user plane bearer reconstruction is successful; when the switching is completed, the target satellite AMF sends a confirmation notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite, and the source satellite AMF clears the UE status data. The present invention can significantly reduce the service interruption time during satellite switching, improve the reliability of state synchronization, effectively solve the problems of large delay, inaccurate prediction, and unreliable state synchronization, and provide users in low-orbit satellite communication networks with a more stable and continuous service experience.

[0074] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or terminal including the element.

[0075] Of course, those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing related hardware (such as a processor, a controller, etc.) through a computer program, and the program can be stored in a computer-readable storage medium that can be read by a computer, and the program can include the processes of the above-mentioned method embodiments when executed. The computer-readable storage medium can be a memory, a disk, an optical disk, etc.

[0076] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for processing inter-satellite handover of a satellite core network access mobility management function unit, characterized in that: The processing method for inter-satellite handover of the satellite-borne core network access mobility management function unit includes: The source satellite RAN obtains satellite orbit parameters and reports them to the source satellite AMF. The source satellite AMF calculates the service overlap area with the target satellite based on the satellite orbit parameters and evaluates the optimal switching time window of the mobile user UE in the service overlap area. The source satellite AMF obtains complete UE context information, sends a handover pre-notification to the target satellite AMF according to the UE context information, and the target satellite AMF reserves a preset storage space and performs resource evaluation; The source satellite AMF locks the UE status data and transmits it to the target satellite AMF. The target satellite AMF stores the UE status data and performs data integrity verification; When entering the optimal switching time window, the source satellite AMF sends a switching command to the source satellite RAN, the source satellite RAN sends a switching instruction to the mobile user UE, the mobile user UE initiates an access request to the target satellite RAN, and the target satellite RAN notifies the target satellite AMF that the switching event has started; The target satellite AMF reads the UE status data, reconstructs the user plane bearer based on the UE status data, and the mobile user UE confirms that the user plane bearer is successfully reconstructed; When the handover is completed, the target satellite AMF sends a confirmation notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite, and the source satellite AMF clears the UE status data.

2. The method for processing inter-satellite handover of a satellite core network access mobility management function unit according to claim 1, characterized in that: The source satellite RAN obtains satellite orbit parameters and reports them to the source satellite AMF. The source satellite AMF calculates the service overlap area with the target satellite according to the satellite orbit parameters and evaluates the optimal switching time window of the mobile user UE in the service overlap area. Specifically, it includes: The source satellite RAN calculates and obtains satellite orbit parameters in real time, and reports the satellite orbit parameters to the source satellite AMF; The source satellite AMF calculates the service overlap area with the target satellite based on the satellite orbit parameters and in combination with the satellite movement speed and coverage range; The source satellite AMF evaluates the optimal switching time window for the mobile user UE in the service overlap area to ensure that the switching occurs at the time when the signal quality is optimal.

3. The method for processing inter-satellite handover of a satellite core network access mobility management function unit according to claim 1, characterized in that: The source satellite AMF obtains complete UE context information, sends a handover pre-notification to the target satellite AMF according to the UE context information, and the target satellite AMF reserves a preset storage space and performs resource evaluation, specifically including: After determining the optimal switching time window, the source satellite AMF obtains complete UE context information from the local source state database; The source satellite AMF sends a handover pre-notification to the target satellite AMF, where the handover pre-notification includes an estimated handover time and context data size; After receiving the switching pre-notification, the target satellite AMF reserves a preset storage space in the local target state database and performs resource evaluation to ensure support for the upcoming user session.

4. The method for processing inter-satellite handover of a satellite core network access mobility management function unit according to claim 3, characterized in that: The UE context information includes authentication status, QoS configuration and session information.

5. The method for processing inter-satellite handover of a satellite core network access mobility management function unit according to claim 1, characterized in that: The source satellite AMF locks the UE status data and transmits it to the target satellite AMF. The target satellite AMF stores the UE status data and performs data integrity verification, specifically including: The source satellite AMF locks the UE status data in the local source status database; The source satellite AMF transmits the complete UE status data to the target satellite AMF via the inter-satellite link; After receiving the complete UE status data, the target satellite AMF stores it in the local target status database and performs data integrity verification.

6. The method for processing inter-satellite handover of a satellite core network access mobility management function unit according to claim 1, characterized in that: When entering the optimal switching time window, the source satellite AMF sends a switching command to the source satellite RAN, the source satellite RAN sends a switching instruction to the mobile user UE, the mobile user UE initiates an access request to the target satellite RAN, and the target satellite RAN notifies the target satellite AMF that the switching event has started, specifically including: When the predetermined optimal switching time window is reached, the source satellite AMF sends a switching command to the source satellite RAN, triggering the air interface switching process; The source satellite RAN sends a handover instruction to the mobile user UE, wherein the handover instruction includes access parameters of the target satellite; The mobile user UE initiates an access request to the target satellite RAN according to the access parameters of the target satellite; After receiving the access request from the mobile user UE, the target satellite RAN notifies the target satellite AMF that the switching event has started.

7. The method for processing inter-satellite handover of a satellite core network access mobility management function unit according to claim 5, characterized in that: The target satellite AMF reads the UE status data, reconstructs the user plane bearer based on the UE status data, and the mobile user UE confirms that the user plane bearer reconstruction is successful, specifically including: The target satellite AMF reads the synchronized UE status data from the local target status database and rebuilds the user plane bearer based on the UE status data; The mobile user UE confirms that the user plane bearer is successfully reestablished to ensure normal service.

8. The method for processing inter-satellite handover of a satellite core network access mobility management function unit according to claim 7, characterized in that: The process of reestablishing the user plane bearer includes restoring QoS configuration, reestablishing PDU session and allocating network resources.

9. The method for processing inter-satellite handover of a satellite core network access mobility management function unit according to claim 1, characterized in that: When the handover is completed, the target satellite AMF sends a confirmation notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite, and the source satellite AMF clears the UE status data, specifically including: When the handover is completed, the target satellite AMF sends a confirmation handover completion notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite; The source satellite AMF cleans up the UE status data in the local source status database and releases related resources; When the local source status database confirms to the source satellite AMF after completing the cleanup, the source satellite AMF notifies the target satellite AMF that the entire switching process has ended.

10. A processing system for inter-satellite handover of a satellite core network access mobility management function unit, characterized in that: The processing system for inter-satellite handover of the satellite-borne core network access mobility management function unit includes: a source satellite RAN, a source satellite AMF, a local source state database, a mobile user UE, a target satellite AMF, a local target state database and a target satellite RAN; The source satellite RAN obtains satellite orbit parameters and reports them to the source satellite AMF. The source satellite AMF calculates the service overlap area with the target satellite based on the satellite orbit parameters and evaluates the optimal switching time window of the mobile user UE in the service overlap area. The source satellite AMF obtains complete UE context information, sends a handover pre-notification to the target satellite AMF according to the UE context information, and the target satellite AMF reserves a preset storage space and performs resource evaluation; The source satellite AMF locks the UE status data and transmits it to the target satellite AMF. The target satellite AMF stores the UE status data and performs data integrity verification; When entering the optimal switching time window, the source satellite AMF sends a switching command to the source satellite RAN, the source satellite RAN sends a switching instruction to the mobile user UE, the mobile user UE initiates an access request to the target satellite RAN, and the target satellite RAN notifies the target satellite AMF that the switching event has started; The target satellite AMF reads the UE status data, reconstructs the user plane bearer based on the UE status data, and the mobile user UE confirms that the user plane bearer is successfully reconstructed; When the handover is completed, the target satellite AMF sends a confirmation notification to the source satellite AMF, indicating that the mobile user UE has successfully accessed the new satellite, and the source satellite AMF clears the UE status data.

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