CN118826813A - An inter-satellite switching method based on on-satellite processing - Google Patents

Abstract

The invention relates to an inter-satellite switching method based on-satellite processing, which belongs to the field of low-orbit satellite mobile communication and comprises the following steps: after receiving the information reported by the satellite communication terminal, the source satellite determines a target satellite for inter-satellite switching and updates a security context; the source satellite sends a switching request to the target satellite based on the information reported by the satellite communication terminal; the target satellite executes a switching preparation process based on the switching request and sends a switching request response to the source satellite; the source satellite sends a switching command to the satellite communication terminal based on the switching request response, and the satellite communication terminal performs switching and establishes connection with the target satellite; and after the target satellite and the ground gateway station perform interactive completion path conversion, notifying the source satellite to release terminal resources to complete switching. The method does not depend on the ground station to finish the switching request and the switching confirmation during switching, encrypts and protects the switching security context, improves the efficiency during switching in a satellite system and ensures the security of communication data.

Description

An inter-satellite switching method based on on-satellite processing

Technical Field

The invention belongs to the field of low-orbit satellite mobile communications, and in particular relates to an inter-satellite switching method based on on-satellite processing.

Background Art

Satellite communication systems are developing towards the trend of integrating with ground networks to form an integrated space-ground information network. Satellite access has the advantage of wide-area coverage. Due to the fast movement speed of low-orbit satellites, frequent inter-satellite switching processes will occur. In order to ensure service continuity, it is necessary to solve the problem of secure switching of access satellites and ensure that security context information is securely transmitted during the switching process to prevent it from being stolen by attackers.

Typical inter-satellite handovers for accessing satellites include two methods: active initiation by satellite communication terminals and passive response. Regardless of the method, when a handover occurs, the terminal needs to establish a communication link with the target satellite to complete the handover. Most existing satellite systems rely on ground stations to complete handover requests and handover confirmations, and after authenticating the terminal identity, they establish a new session key and send it to the target satellite to complete the establishment of the communication link. This handover method relying on ground stations increases the link communication delay and has low switching efficiency. In addition, the newly established session key and security context are not protected and are vulnerable to attacks, resulting in the lack of security for the communication data after the handover.

Summary of the invention

In view of the above analysis, the present invention aims to provide an inter-satellite switching method based on on-board processing, which does not rely on the ground station to complete the switching request and switching confirmation during switching, and encrypts and integrity protects the security context during switching, thereby improving the efficiency of inter-satellite switching and ensuring the security of communication data.

The present invention provides an inter-satellite handover method based on on-satellite processing, which specifically comprises the following steps:

After receiving the information reported by the satellite communication terminal, the source satellite determines the target satellite for inter-satellite handover and updates the security context;

The source satellite sends a handover request to the target satellite based on the information reported by the satellite communication terminal;

The target satellite performs a handover preparation process based on the handover request and sends a handover request response to the source satellite;

The source satellite sends a switching command to the satellite communication terminal based on the switching request response, and the satellite communication terminal executes the switching to establish a connection with the target satellite;

After the target satellite interacts with the ground gateway to complete the path conversion, it notifies the source satellite to release terminal resources to complete the switch.

Further, the updating of the security context includes:

After receiving the information reported by the satellite communication terminal, the source satellite derives a new satellite base station key KsNB* horizontally according to the satellite base station key KsNB or vertically according to the next hop key NH;

The source satellite encrypts and integrity protects KsNB* to obtain the encrypted and integrity protected KsNB*, that is, the updated security context.

Furthermore, the handover request includes a target satellite ID, a terminal context, an updated security context, and RRC and UP key derivation algorithms supported by the terminal.

Further, the target satellite performs a handover preparation process based on the handover request, including:

The target satellite performs integrity check and decryption on the updated security context in the handover request to obtain KsNB*, and derives an AS layer security key based on KsNB* to ensure secure communication of the air interface between the satellite communication terminal and the target satellite;

The target satellite reserves air interface RRC radio resources for the satellite communication terminal based on the terminal context and QoS and creates a data radio bearer identifier.

Furthermore, the handover request response includes a target satellite ID, a data radio bearer identifier, an AS security algorithm of the target satellite, and an algorithm ID and parameters used to derive an RRC key and an UP key.

Further, the source satellite sends a switching command to the satellite communication terminal based on the switching request response, and the satellite communication terminal executes the switching to establish a connection with the target satellite, including:

The source satellite sends a handover command message to the satellite communication terminal, wherein the handover command message includes an algorithm ID and parameters used by the derived RRC key and UP key obtained based on the handover request response and an AS security algorithm of the target satellite;

After receiving the switching command, the satellite communication terminal enters the switching interruption time;

After the source satellite sends a state transition message to the target satellite, the source satellite forwards the data packet to the target satellite, and the target satellite caches the data packet;

The satellite communication terminal sends a switching confirmation message to the target satellite and establishes a connection with the target satellite after detecting the synchronization signal of the target satellite.

Further, the satellite communication terminal enters the switching interruption time after receiving the switching command, including:

The satellite communication terminal detaches from the source satellite and derives KsNB* synchronized with the target satellite;

The satellite communication terminal derives an AS layer security key synchronized with the target satellite based on KsNB* using the AS security algorithm of the target satellite.

Further, the target satellite interacts with the ground gateway to complete the path conversion, including:

The target satellite sends a path switching request message to the ground gateway;

The ground gateway forwards the path switching request message to the AMF of the core network;

The AMF of the core network generates a new {NH, NCC} pair and encrypts and integrity protects the NH;

The AMF sends a path switching response message to the ground gateway, where the path switching response message includes the encrypted and integrity protected new {NH, NCC} pair;

The ground gateway forwards the path switching response message to the target satellite.

Further, the notifying the source satellite to release terminal resources to complete the handover includes:

The target satellite sends a context release message to the source satellite;

The source satellite releases the resources of the satellite communication terminal based on the context release message, completing the handover.

Furthermore, the information reported by the satellite communication terminal includes:

Switching application message of satellite communication terminal;

Or, measurement reports reported by satellite communication terminals.

The present invention can achieve at least one of the following beneficial effects:

By proposing a solution for satellite-borne secure switching control plane from the perspective of full life cycle maintenance of security context, the inter-satellite switching method is adjusted from relying on ground stations to complete switching requests and switching confirmations to on-board processing. Single-hop signaling message interaction between satellite terminals and satellites is achieved through on-board RRC message processing, without the need for processing by ground signal gateways, which greatly reduces the propagation delay of the switching process transmission path and improves the efficiency of inter-satellite switching.

By updating the security context based on on-satellite switching and protecting the confidentiality and integrity of the security context key information through a public key encryption mechanism, the security of the security context during switching is improved, thereby improving the security of subsequent air interface signaling and service data transmission.

Other features and advantages of the present invention will be described in the following description, and some advantages may become apparent from the description, or may be understood by practicing the present invention. The purpose and other advantages of the present invention may be realized and obtained through the contents particularly pointed out in the description, claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

FIG1 is a flow chart of an inter-satellite handover method according to the present invention;

FIG2 is a schematic diagram of the inter-satellite handover process;

FIG3 is a flow chart showing the update process of the security context KsNB during the handover process;

Figure 4 shows the confidentiality and integrity protection of KsNB* by satellite switching;

Figure 5 shows the confidentiality and integrity protection of NH by satellite switching;

Figure 6 shows the onboard safety process.

DETAILED DESCRIPTION

The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

Embodiment 1

A specific embodiment of the present invention discloses an inter-satellite handover method based on on-satellite processing, which specifically includes:

Step S01: After receiving information reported by a satellite communication terminal, the source satellite determines the target satellite for inter-satellite handover and updates the security context.

Specifically, the information reported by the satellite communication terminal includes a handover application message of the satellite communication terminal or a measurement report reported by the satellite communication terminal, which respectively corresponds to two modes of active initiation or passive response by the satellite communication terminal.

Specifically, the satellite communication terminal actively initiates the following scenario:

When the satellite communication terminal UE moves from the coverage area of the source satellite to the coverage area of the target satellite, when the satellite signal strength (Satellite Signal Received Power, SSRP) of the UE in the coverage area of the source satellite is lower than the threshold value ss-Measure, the UE starts to measure the satellite signal strength of the neighboring area (the coverage area of the target satellite); the UE finds through measurement that the SSRP of the neighboring area is getting higher and higher, and the signal is gradually getting stronger. When SSRP _B > SSRP _A and SSRP _B > ss-Measure within the duration timeToTrigger (time parameter), the UE determines that the target satellite signal is more stable and stronger than the source satellite signal, and generates a handover application message Handover Application to send to the source satellite. Among them, SSRP _B represents the satellite signal strength in the coverage area of the target satellite, and SSRP _A represents the satellite signal strength in the coverage area of the source satellite.

Specifically, the satellite communication terminal passively responds to the scenario;

The source satellite performs measurement configuration on the UE in the coverage area through RRC Connection Reconfiguration, and the UE monitors the wireless channel according to the relevant configuration. Based on the measurement configuration items sent by the source satellite, the UE performs measurement. When the signal quality received from the target satellite is higher than the threshold value and stronger than the signal of the source satellite within the continuous timeToTrigger time, a handover event is triggered, and a measurement report is generated and reported to the source satellite.

Specifically, step S01 includes the following steps:

S011. After receiving the information reported by the satellite communication terminal, the source satellite performs a target switching decision and determines the target satellite. Specifically, the reported information includes the target satellite ID.

S012. After receiving the information reported by the satellite communication terminal, the source satellite derives a new satellite base station key KsNB* horizontally according to the satellite base station key KsNB or vertically according to the next hop key NH.

Specifically, after the first access is successful or the last handover is completed, the source satellite base station sNB (Satellite Node B) stores KsNB (satellite base station key) or NH (next hop key). The source satellite derives a new KsNB* horizontally or vertically based on KsNB. Figure 3 shows the update process of the security context KsNB during the handover process, that is, deriving a new KsNB* horizontally or vertically based on KsNB.

S013. The source satellite encrypts and integrity protects KsNB* to obtain the encrypted and integrity protected KsNB*, that is, the updated security context.

Specifically, the protection mechanism for KsNB* is based on the public key cryptography system. The source satellite uses the preset key protection key PK of the target satellite to encrypt and protect the integrity of KsNB*. Specifically, each satellite in inter-satellite switching stores the correspondence table between other satellites and public key information in advance. When switching, the public key information of the target satellite is found based on the correspondence table and the target satellite ID. Figure 4 shows the confidentiality and integrity protection process of KsNB* by the source satellite.

Step S02: The source satellite sends a switching request to the target satellite based on the information reported by the satellite communication terminal.

Specifically, the handover request Handover Request includes the target satellite ID, the terminal context UEContext info, the updated security context (i.e., the encrypted and integrity protected KsNB*), and the RRC and UP key derivation algorithms supported by the terminal. Specifically, after the source satellite and the satellite communication terminal establish a connection, the source satellite receives the RRC and UP key derivation algorithms supported by the terminal from the terminal.

Step S03: The target satellite performs a handover preparation process based on the handover request and sends a handover request response to the source satellite.

Specifically, the handover preparation process includes:

The target satellite performs integrity check and decryption on the updated security context in the handover request to obtain KsNB*, and uses supported RRC-enc-alg, RRC-int-alg, UP-int-al and UP-enc-alg algorithms to derive AS layer security keys (including KRRCint, KRRCenc, KUPint, KUPenc) based on KsNB* to ensure secure communication of the air interface between the satellite communication terminal and the target satellite;

The target satellite reserves air interface RRC radio resources for the satellite communication terminal based on the terminal context and QoS and creates a data radio bearer identifier DRB ID (UL/DL).

Specifically, the handover request response includes the target satellite ID, the data radio bearer identifier, the AS security algorithm of the target satellite, and the algorithm ID and parameters used to derive the RRC key and the UP key.

Specifically, when the target satellite decrypts the updated security context in the handover request, it uses the private key corresponding to the encryption public key used by the source satellite for encryption to decrypt and obtain KsNB*.

Step S04: The source satellite sends a switching command to the satellite communication terminal based on the switching request response, and the satellite communication terminal executes the switching to establish a connection with the target satellite.

Step S04 includes the following steps:

S041. The source satellite sends a switching command message to the satellite communication terminal, where the switching command message includes the AS security algorithm of the target satellite and the algorithm ID and parameters used by the derived RRC key and UP key obtained based on the switching request response.

S042. After receiving the switching command, the satellite communication terminal enters the switching interruption time.

Specifically, during the handover interruption time period, the satellite communication terminal detaches from the source satellite and derives KsNB* synchronized with the target satellite based on the satellite base station key KsNB or the next hop key that has been synchronized with the source satellite;

The satellite communication terminal derives AS layer security keys (including KRRCint, KRRCenc, KUPint, KUPenc) based on the derived KsNB* synchronized with the target satellite using the AS security algorithm of the target satellite, and synchronizes with the AS layer security keys of the target satellite in step S03.

S043: After sending a state transfer message to the target satellite, the source satellite forwards the data packet to the target satellite, and the target satellite buffers the data packet.

Specifically, the target satellite knows which data packet to start sending or receiving through the status transfer message SN Status Transfer. After sending SN Status Transfer, the source satellite starts forwarding downlink data packets sent from the core network through the ground gateway, and the target satellite caches these data packets and waits for the satellite communication terminal to complete access.

S044. The satellite communication terminal sends a switching confirmation message to the target satellite, and establishes a connection with the target satellite after detecting the synchronization signal of the target satellite.

Specifically, the satellite communication terminal UE sends a handover confirmation message Handover Confirm to the target satellite, and accesses the target satellite after the UE detects the synchronization signal of the target satellite. Once the synchronization is completed, the UE initiates a non-competitive random access. An RRC connection, SRB signaling radio bearer and DRB data radio bearer are established between the UE and the target satellite. The successful access of the UE to the target satellite indicates that the UE can send or receive data packets from the cache of the target satellite, and the handover interruption time period ends.

At this point, all RRC signaling messages and user data packets on the wireless link between the UE and the target satellite are securely transmitted using the AS layer security key.

Step S05: After the target satellite interacts with the ground gateway to complete the path switching, it notifies the source satellite to release the terminal resources to complete the switching.

Step S05 specifically includes the following steps:

S051. The target satellite sends a path switch request message Path Switch Request to the ground gateway.

S052. The ground gateway forwards the path switching request message to the AMF of the core network.

S053. The AMF of the core network generates a new {NH, NCC} pair based on the path switching request message, and calls the ground cryptographic machine to encrypt and integrity protect the NH using the key protection key (PK).

Specifically, the core network ground cipher machine pre-sets and saves the ID and PK public key correspondence table of each satellite in advance, and calls the public key information PK of the target satellite found based on the correspondence table for encryption when encrypting the NH.

S054. AMF sends a path switch response message Path Switch Request Ack to the ground gateway, where the path switch response message includes the encrypted and integrity protected new {NH, NCC} pair.

S055. The ground gateway forwards the Path Switch Request Ack of the path switch response message to the target satellite.

At this point, uplink and downlink transmission channels and bearers have been established between the satellite communication terminal and the target satellite, and between the target satellite and the ground gateway.

S056. After receiving the path switching response message, the target satellite sends a context release message to the source satellite.

Specifically, after receiving the path switching response message, the target satellite verifies the integrity of the encrypted and integrity protected new {NH, NCC} pair, and then decrypts it with the private key corresponding to the public key during encryption to obtain the new NH information of the response. The public key during encryption is the public key information of the target satellite in step S053. FIG5 shows the process of satellite switching NH confidentiality and integrity protection.

S057. The source satellite releases the resources of the satellite communication terminal based on the context release message, thereby completing the handover.

Figure 2 is a schematic diagram of the above intersatellite handover process. During implementation, the satellite must support secure handover processing related RRC, PDCP, RLC, MAC and other air interface protocols, as well as satellite intersatellite control plane transmission protocol and user plane transmission protocol, so that the satellite has the high-level processing capability of the on-board protocol stack and can actively respond to and process handover signaling messages; and the satellite has on-board security processing functions: encryption and decryption and integrity protection of satellite base station air interface signaling/service data, encryption and decryption and integrity protection of satellite intersatellite signaling/service data, and maintenance of security context, etc.

The present embodiment discloses an inter-satellite switching method based on on-board processing. By proposing a solution of a satellite-borne secure switching control plane from the perspective of full life cycle maintenance of the security context, the inter-satellite switching method is adjusted from relying on a ground station to complete the switching request and switching confirmation to on-board processing. Single-hop signaling message interaction between a satellite terminal and a satellite is realized through on-board RRC message processing, without the need for processing by a ground signal gateway, which greatly reduces the propagation delay of the switching process transmission path and improves the efficiency of inter-satellite switching. By updating the security context based on on-board switching and protecting the confidentiality and integrity of the key information of the security context through a public key encryption mechanism, the security of the security context during switching is improved, thereby improving the security of subsequent air interface signaling and service data transmission.

Embodiment 2

Another specific embodiment of the present invention discloses an inter-satellite handover method based on on-board processing, including a handover preparation process (steps S21-S23), a handover execution process (step S24) and a handover completion process (step S25).

Specifically, the satellite supporting the method of this embodiment supports the control plane and user plane protocols related to secure switching processing, so that the satellite has the high-level processing capability of the on-board protocol stack, can actively respond to and process the switching signaling message, and maintain the security context. Specifically, the satellite processing signaling data system includes a user-side transceiver, an inter-satellite transceiver, an on-board central processing unit, and an on-board security processing unit. Among them, the on-board security processing unit implements satellite base station air interface signaling/service data encryption and decryption and integrity protection, satellite inter-satellite signaling/service data encryption and decryption and integrity protection, and maintains security context; the central processing unit implements high-level processing of the on-board protocol stack.

Specifically, the method of this embodiment includes:

Step S21: After receiving the information reported by the satellite communication terminal, the source satellite determines the target satellite for inter-satellite handover and updates the security context.

Specifically, for a handover scenario actively initiated by a satellite communication terminal: a source satellite user-side transceiver receives an air interface signaling (handover request message) from the satellite communication terminal and sends it to an onboard central processing unit.

For the switching scenario of the satellite communication terminal passive response:

The source satellite's onboard central processing unit generates an RRC connection reconfiguration message (measurement configuration) and calls the onboard security processing unit to encrypt and integrity protect the RRC signaling. The RRC message is sent to the satellite communication terminal through the user-side transceiver. The satellite communication terminal receiver forwards the signaling to the terminal security module, which performs integrity verification and decryption on the RRC signaling. The terminal performs measurements according to the measurement configuration sent by the satellite, and reports the measurement report to the source satellite after the event is triggered. The source satellite user-side transceiver receives the measurement report from the satellite communication terminal and sends it to the onboard central processing unit.

Specifically, step S21 includes the following steps:

S211. After receiving the information reported by the satellite communication terminal, the central processing unit of the source satellite makes a target switching decision and determines the target satellite.

S212. After receiving the information reported by the satellite communication terminal, the central processing unit of the source satellite horizontally derives a new satellite base station key KsNB* according to the satellite base station key KsNB or vertically derives the next hop key NH.

S213. The onboard security processing unit of the source satellite encrypts and integrity protects KsNB* to obtain the encrypted and integrity protected KsNB*, that is, the updated security context.

Step S22: The source satellite sends a switching request to the target satellite based on the information reported by the satellite communication terminal.

Specifically, the central processing unit of the source satellite extracts KsNB* from the security processing unit and encapsulates it in the switching request. The source satellite sends the switching request to the target satellite through the inter-satellite side transceiver.

Step S23: The target satellite performs a handover preparation process based on the handover request and sends a handover request response to the source satellite.

Specifically, the satellite inter-satellite transceiver of the target satellite receives the switching request of the source satellite and forwards it to the on-board central processing unit of the target satellite; the central processing unit transmits the information to the on-board security processing unit; the on-board security processing unit decrypts with the corresponding private key to obtain KsNB*, and stores KsNB* securely locally. The on-board security processing unit uses the security algorithm parameters to derive the AS layer related security keys.

The target satellite reserves air interface resources for the terminal access and creates a data radio bearer identifier. The on-board central processing unit generates a handover request response message and sends it to the source satellite via the inter-satellite transceiver.

Step S24: The source satellite sends a switching command to the satellite communication terminal based on the switching request response, and the satellite communication terminal executes the switching to establish a connection with the target satellite.

Specifically, the source satellite intersatellite side receiver receives the handover response message; the user side transceiver carries the handover command in the downlink control channel and sends it to the satellite communication terminal. The satellite communication terminal receiver receives the handover command, and the terminal security processing module derives the KsNB* and AS layer security keys synchronized with the target satellite.

Step S25: After the target satellite interacts with the ground gateway to complete the path switching, it notifies the source satellite to release the terminal resources to complete the switching.

FIG6 illustrates the on-board safety processing flow in this embodiment.

Compared with the prior art, the inter-satellite switching method based on on-satellite processing disclosed in this embodiment has substantially the same beneficial effects as those of the first embodiment, and will not be described in detail herein.

It should be noted that the above embodiments are based on the same inventive concept and parts not described repeatedly can be used as reference for each other.

The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims (10)

1. An inter-satellite switching method based on-satellite processing is characterized by comprising the following steps:

After receiving the information reported by the satellite communication terminal, the source satellite determines a target satellite for inter-satellite switching and updates a security context;

the source satellite sends a switching request to the target satellite based on the information reported by the satellite communication terminal;

the target satellite executes a switching preparation process based on the switching request and sends a switching request response to the source satellite;

the source satellite sends a switching command to the satellite communication terminal based on the switching request response, and the satellite communication terminal performs switching and establishes connection with the target satellite;

And after the target satellite and the ground gateway station perform interactive completion path conversion, notifying the source satellite to release terminal resources to complete switching.

2. The inter-star handoff method of claim 1, wherein updating the security context comprises:

After receiving the information reported by the satellite communication terminal, the source satellite horizontally derives a new satellite base station key KsNB according to the satellite base station key KsNB or vertically derives a new satellite base station key NH according to the next hop key;

The source satellite encrypts and integrity protects KsNB, ksNB of encryption and integrity protection, i.e., updated security context.

3. The inter-satellite handover method of claim 2, wherein the handover request includes a target satellite ID, a terminal context, an updated security context, and RRC and UP key derivation algorithms supported by the terminal.

4. The inter-satellite handover method according to claim 3, wherein the target satellite performing a handover preparation process based on a handover request comprises:

The target satellite carries out integrity check and decryption on the updated security context in the switching request to obtain KsNB, derives an AS layer security key based on KsNB, and is used for ensuring the secure communication of an air interface between the satellite communication terminal and the target satellite;

the target satellite reserves air interface RRC radio resources for the satellite communication terminal based on the terminal context and QoS and creates a data radio bearer identification.

5. The inter-satellite handoff method of claim 4 wherein the handoff request response includes a target satellite ID, a data radio bearer identification, an AS security algorithm for the target satellite, and algorithm IDs and parameters used to derive RRC keys and UP keys.

6. The inter-satellite handoff method according to claim 5, wherein said source satellite transmitting a handoff command to a satellite communication terminal based on a handoff request response, the satellite communication terminal performing handoff to establish a connection with a target satellite comprises:

the source satellite sends a switching command message to the satellite communication terminal, wherein the switching command message comprises an algorithm ID and parameters used by the derived RRC key and the UP key obtained based on a switching request response and an AS security algorithm of the target satellite;

the satellite communication terminal enters the switching interruption time after receiving the switching command;

After the source satellite sends a state conversion message to the target satellite, forwarding a data packet to the target satellite, and caching the data packet by the target satellite;

The satellite communication terminal transmits a switching confirmation message to the target satellite, and establishes connection with the target satellite after detecting the synchronous signal of the target satellite.

7. The inter-satellite handover method according to claim 6, wherein the satellite communication terminal entering a handover interruption time after receiving a handover command comprises:

The satellite communication terminal is detached from the source satellite and derives KsNB which is synchronous with the target satellite;

the satellite communication terminal derives an AS layer security key synchronized with the target satellite according to KsNB x using the AS security algorithm of the target satellite.

8. The inter-satellite handoff method according to claim 6, wherein said interaction completion path switching between said target satellite and a ground gateway station comprises:

the target satellite sends a path conversion request message to the ground gateway station;

The ground gateway station forwards the path conversion request message to the AMF of the core network;

AMF of core network generates new { NH, NCC } pair, and encrypts and integrity protects the NH;

The AMF sends a path switch response message to the ground gateway station, wherein the path switch response message comprises the new { NH, NCC } pair of encryption and integrity protection;

The ground gateway station forwards the path switch response message to the target satellite.

9. The inter-satellite handoff method according to claim 8, wherein said notifying a source satellite of a terminal resource completion handoff comprises:

The target satellite sends a context release message to the source satellite;

the source satellite releases the resources of the satellite communication terminal based on the context release message to complete the switching.

10. The inter-satellite switching method according to claim 1, wherein the information reported by the satellite communication terminal includes:

a switching application message of the satellite communication terminal;

or, the satellite communication terminal reports the measurement report.