A satellite network mobility management method and system based on PMIPv6

Abstract

The present invention discloses a satellite network mobility management method and system based on PMIPv6, belonging to the field of satellite communication. The system includes multiple distributedly deployed location mobile anchor points LMA, ground stations, ground service networks and mobile access satellite MAS. Among them, LMA serves as a key management node for the interaction between the ground service network and the satellite network, responsible for user mobility management, data forwarding and information synchronization between LMAs. MAS serves as a user satellite network access point, allocates a fixed IP address of the same network segment to the user, acts as a router to publish the network segment route, and selects a suitable LMA for user registration. The mobility management method includes mechanisms such as user registration, switching, data forwarding and LMA synchronization. The present invention improves the accessibility and reliability of the ground service network backhaul routing in the low-orbit satellite network, realizes efficient two-way data transmission between users and the ground network, and is suitable for future large-scale LEO satellite communication systems.

Description

Technical Field

[0001] The present invention relates to the field of satellite communication technology, and mainly to a PMIPv6-based satellite network mobility management method and system. Background Art

[0002] With the rapid development of satellite communication systems, LEO satellites have the advantages of low latency, high spectrum efficiency, and flexible networking compared to traditional geostationary orbit satellites. They are very suitable for providing services for wide-area, highly dynamic mobile communications. However, their high dynamics and global coverage have brought new challenges to mobility management. The traditional centralized architecture based on Mobile IPv6 (MIPv6) and Proxy MIPv6 (PMIPv6) has many limitations when facing low-orbit satellite networks.

[0003] In recent years, intersatellite link technology has gradually matured, and the method and system for deploying IP routing on satellites has gradually become the focus of the industry. This method and system requires the deployment of routing forwarding functions on satellites, so that satellites can directly process and forward IP data packets.

[0004] The design of a single Home Agent (HA) or Local Mobility Anchor (LMA) in the traditional architecture is prone to performance bottlenecks. In low-orbit satellite networks, due to the large number of satellites and frequent user switching, a single HA or LMA may not be able to handle a large amount of signaling interaction and data forwarding, resulting in system performance degradation and even single point failure.

[0005] The routing efficiency issue in highly dynamic networks cannot be ignored. The rapid movement of LEO satellites causes frequent changes in network topology. Traditional triangular routing mechanisms may cause serious traffic detours, increase end-to-end latency, and reduce network efficiency.

[0006] Insufficient cross-regional support is also a prominent problem. The global coverage characteristics of low-orbit satellite networks require mobility management methods and systems to support users' seamless switching between different geographical areas, but traditional architectures perform poorly in this regard.

[0007] The data traffic pattern in the low-orbit satellite network also presents unique characteristics, mainly including ground network traffic and inter-satellite terminal traffic. Among them, ground network traffic occupies a dominant position, mainly involving the communication of users accessing the ground service network through the satellite network; while inter-satellite terminal traffic is relatively small, mainly the communication between users directly through the satellite network without passing through the ground service network. This unbalanced traffic distribution may lead to a waste of bandwidth resources and affect the overall performance of the network.

[0008] Therefore, a new mobility management method and system are needed to solve the above problems and improve the performance and efficiency of satellite networks, especially low-orbit satellite networks. The present invention aims to provide a satellite network mobility management method and system based on PMIPv6, which adopts the strategy of deploying IP routing on board to cope with the unique challenges of low-orbit satellite networks. Summary of the invention

[0009] Purpose of the invention: To provide a satellite network mobility management method and system based on PMIPv6 to solve the deficiencies of the existing satellite network centralized mobility management architecture in terms of scalability, reliability, routing efficiency, etc., and to achieve efficient, flexible, and secure global coverage mobile communication services. The present invention achieves efficient and reliable satellite network mobility management by distributing location mobility anchors (LMA) and introducing new functional node definitions and communication mechanisms, taking a low-orbit satellite network as an example.

[0010] To achieve the above objectives, the present invention first provides a satellite network mobility management system based on PMIPv6, which constructs a mobility management architecture including a location mobility anchor (LMA), a ground station, a ground service network and a mobile access satellite (Mobile Access Satellite, MAS). The LMA is responsible for the following functions:

[0011] Maintain global user information and network status;

[0012] Manage user mobility, store user location and service information;

[0013] Use the tunnel mechanism to forward data and select the optimal route;

[0014] Realize information synchronization and coordination between LMAs.

[0015] The ground station is a key node for the intercommunication between the satellite network and the ground service network, responsible for the signaling interaction and data transfer between the satellite and the ground. In each ground station management area, only one ground station is set up, and LMA is deployed in the area; the ground service network is responsible for serving users' ground data services; the MAS is a user access satellite of the satellite network, responsible for terminal access authentication, configuring the network segment accessed by the terminal user as a router, and publishing the network segment route to the network. At the same time, the MAS assigns a home address (HoA) to the user terminal, manages the terminal location information and session connection information within the coverage area, provides the necessary data forwarding function when the terminal moves and switches, and interacts with the LMA for mobility-related signaling. The MAS that the user initially registers to access serves as the user's proxy location mobile satellite (PLMS), responsible for the user's tunnel establishment and cache establishment when forwarding inter-satellite terminal traffic.

[0016] The present invention provides a satellite network distributed mobility management method based on the above satellite network mobility management system, comprising the following main steps:

[0017] 1. LMA deployment:

[0018] a) Deploy multiple LMAs, and deploy LMAs in the areas where ground stations are located as boundary nodes that interact with the ground service network. Ground station management areas are delineated based on user density, communication needs, and network load. For example, areas with low population density and low communication needs such as ocean deserts can be delineated into larger management areas to achieve global coverage. Each ground station management area has only one ground station and at least one LMA deployed. In the future, multiple LMAs can be deployed based on communication needs and traffic loads to improve reliability. This method takes the deployment of one LMA as an example.

[0019] b) Establish secure communication links between LMAs;

[0020] c) Initialize the LMA user information database.

[0021] 2. User registration:

[0022] The user equipment initially attaches to a MAS, which is the PLMS of the user, and the user sends a registration request to the PLMS;

[0023] PLMS assigns a Home Address (HoA) to the user and replies with a registration confirmation message, which contains the IP address assigned to the user;

[0024] PLMS selects the most suitable LMA as the master LMA according to the predetermined rules and sends a ProxyBinding Update (PBU) message to it;

[0025] The primary LMA processes the PBU message and creates a user binding cache entry (BCE).

[0026] The master LMA sends a Proxy Binding Acknowledgement (PBA) message to the PLMS;

[0027] The master LMA synchronizes the user's registration message with other LMAs.

[0028] 3. User switching:

[0029] The user switches from the previously accessed MAS (pMAS) to the new MAS (nMAS);

[0030] nMAS sends PBU message to user equipment PLMS and pMAS;

[0031] The user PLMS updates the BCE, and the user pMAS releases the binding with the user, and both reply the PBA message to the nMAS;

[0032] nMAS updates BCE and selects the master LMA based on the ephemeris data, and sends a PBU message to the master LMA;

[0033] The current master LMA updates the BCE and sends a PBA message to the nMAS;

[0034] The current master LMA sends a user information synchronization message to other LMAs.

[0035] 4. LMA synchronization mechanism:

[0036] The current master LMA generates a synchronization message when the user's BCE changes, including user registration, switching, deregistration and BCE regular update, which will cause the user's BCE to change. The synchronization message contains the user ID, IP address, access MAS, and location information;

[0037] The master LMA sends synchronization messages to all other LMAs;

[0038] After receiving the synchronization message, other LMAs update their local BCEs.

[0039] 5. Data forwarding is divided into two categories: ground network traffic forwarding and intersatellite terminal traffic forwarding. The former is the data that users access the ground server through the satellite network, and the latter is the data that users communicate directly through satellites:

[0040] (1) Ground network traffic forwarding:

[0041] The ground service network selects the optimal distributed LMA to send data packets based on the estimated routing path and load conditions;

[0042] LMA processes data packets using tunnel encapsulation technology based on cache information;

[0043] The LMA forwards the encapsulated data packet to the MAS to which the target user is connected;

[0044] MAS decapsulates the data packet and forwards it to the target user.

[0045] (2) Inter-satellite terminal traffic forwarding:

[0046] When inter-satellite terminal traffic is forwarded between user terminals, the MAS initially registered by both users acts as a proxy position mobile satellite (PLMS) and is responsible for tunnel establishment and cache establishment when users switch:

[0047] The communication user sends a data packet to the target user PLMS;

[0048] The target user's PLMS queries the target user's location information;

[0049] The target user's PLMS forwards the data packet to the target user's currently accessed MAS through an intersatellite link using a tunneling method;

[0050] The MAS currently accessed by the target user decapsulates the data packet and forwards the data packet to the target user;

[0051] At the same time, the target user also uses the same forwarding process to send data packets to the communication user, and tunnel forwarding is performed through the communication user's PLMS.

[0052] Therefore, when a user requests a ground network service, the ground network service backhaul can obtain the best end-to-end delay by calculating which LMA to forward through; further, when the user switches, it is also necessary to perform binding updates to the user's PLMS to cope with inter-satellite terminal traffic forwarding.

[0053] Beneficial effects:

[0054] The present invention proposes a satellite network mobility management method and system based on PMIPv6. By deploying multiple LMAs, the method and system effectively solve the single point failure and scalability problems faced by the traditional centralized architecture, and improve the reliability and flexibility of the satellite network system, especially the low-orbit satellite network. The collaboration between LMAs and the optimized routing mechanism reduce data transmission delays and improve network performance. At the same time, the architecture better supports users' seamless roaming around the world, especially meeting the special needs of low-orbit satellite networks.

[0055] The design of the present invention based on the PMIPv6 protocol ensures the stability of the user's IP address. As long as the user remains connected, his IP address can remain unchanged even if the MAS is frequently switched. This mechanism greatly reduces the risk of communication interruption, improves user experience, and provides reliable support for applications and services that require IP address stability.

[0056] The optimized synchronization strategy and localized processing of the present invention reduce signaling overhead and enhance the scalability of the system. In addition, the distributed architecture and secure communication mechanism ensure the security of user data and network resources. The design based on the PMIPv6 protocol makes the method and system have good compatibility and is easy to deploy and integrate on the existing network infrastructure. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The figure is a schematic diagram of the architecture of a satellite network mobility management method and system based on PMIPv6 in an embodiment of the present invention.

[0058] Figure 2 Schematic diagram of distributed deployment of LMA in an embodiment of the present invention.

[0059] Figure 3 Schematic diagram of user registration process in an embodiment of the present invention.

[0060] Figure 4 The figure is a schematic diagram of a user switching process in an embodiment of the present invention.

[0061] Figure 5 Schematic diagram of the ground network traffic data forwarding process in an embodiment of the present invention.

[0062] Figure 6 The figure is a schematic diagram of the inter-satellite terminal traffic data forwarding process in an embodiment of the present invention. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the embodiments of the present invention are described in detail below in conjunction with the accompanying drawings: This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given. It should be understood that the specific examples described here are only used to explain the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0064] Embodiment 1: This embodiment provides a satellite network mobility management system based on PMIPv6, such as Figure 1 As shown, the PMIPv6-based satellite network mobility management system of this embodiment includes distributedly deployed LMA, ground stations, ground service networks and MAS.

[0065] LMA is the core component of this system. It is responsible for maintaining global user information and network status, managing user mobility, storing user location and service information, forwarding data using the tunnel mechanism, selecting the optimal route, and achieving information synchronization and coordination between LMAs. Specifically, it includes:

[0066] Maintain and manage the user's binding cache entry BCE, record user ID, user IP address, user access MAS, user location, and user service parameters;

[0067] Use tunneling mechanism to forward data packets from ground service network or other users to the access MAS of target users;

[0068] Synchronize user BCE information with other LMAs through dedicated links.

[0069] The ground station is a key node for communication between the satellite network and the ground service network, and is responsible for signaling interaction and data transfer between the satellite and the ground. At the same time, the location of the ground station is an important basis for dividing the PMIPv6 management domain.

[0070] The ground service network is responsible for serving user ground data services and processing various data requests from ground users (UE). These ground service networks maintain close communication with LMA to ensure fast transmission of user data.

[0071] Mobile Access Satellite (MAS), as the user access satellite of the satellite network, is responsible for terminal access authentication, configures the network segment for terminal user access as a router, and publishes the network segment route to the network. At the same time, MAS assigns a unique IP address to the terminal, manages the terminal location information and session connection information within the coverage area, provides necessary data forwarding functions when the terminal moves and switches, and interacts with LMA for mobility-related signaling. When the user initially registers, it can act as a proxy position mobile satellite (PLMS), responsible for tunnel establishment and cache establishment when the user forwards inter-satellite terminal traffic.

[0072] Embodiment 2:

[0073] The difference between this embodiment and embodiment 1 is that the LMA is distributedly deployed in the PMIPv6-based satellite network mobility management system in this embodiment, such as Figure 2 As shown, this embodiment adopts the LMA distributed deployment strategy. Figure 2 In the figure, LMA1, LMA2, LMA3, LMA4, LMA5, and LMA6 represent an LMA deployed in each ground station management area; MAS5, MAS6, MAS7, and MAS8 represent satellites in a PMIPv6 domain. The deployment location of LMA takes into account the following factors:

[0074] Geographic distribution: Ground station management areas are delineated based on user density, communication needs, and network load. For example, areas with low population density and small communication needs, such as ocean deserts, can be delineated into larger management areas, and only one LMA is deployed in each ground station management area to achieve global coverage.

[0075] Network topology: LMA is deployed on network backbone nodes to optimize network connectivity and data transmission efficiency.

[0076] Redundant design: Backup LMAs can be deployed at key locations to improve system reliability.

[0077] LMAs can transmit and synchronize messages through the ground network, and can transmit and synchronize messages through the satellite network if the distance is far. Each LMA is responsible for user management within a certain range. This design ensures the efficiency of local processing and achieves the consistency of global information.

[0078] Embodiment 3:

[0079] This embodiment is a method for satellite network mobility management using the above-mentioned PMIPv6-based satellite network mobility management system. The PMIPv6-based satellite network mobility management system dynamically divides PMIPv6 domains according to the LMA in the ground station management area. A PMIPv6 domain consists of a main LMA and all MASs managed by it in the current time slice; according to the satellite ephemeris and orbital period, the time is divided into several equal time slices. Each MAS that accesses the satellite as a satellite network user terminal can infer the ground station management area and the LMA in the domain in the current time slice according to its ephemeris information. The LMA that manages the MAS is designated as the main LMA of the MAS. In each time slice, each MAS is located in a specific ground management area, and the LMA in the area is the main LMA of the MAS. In different time slices, the area to which the MAS belongs and the corresponding main LMA can change dynamically. A PMIPv6 domain consists of a main LMA and all MASs managed by it in the current time slice. This dynamic division method can adapt to the high dynamic characteristics of the low-orbit satellite network and ensure efficient utilization and flexible management of network resources. The distributed PMIPv6 protocol deployment supports users to keep the same IP address when switching between different access MASs, and the information synchronization mechanism between LMAs ensures accurate data routing and continuous communication when users move at high speed and frequently switch satellites, thereby realizing the mobility management process including user registration, user switching, LMA synchronization mechanism, ground network traffic forwarding and inter-satellite terminal traffic forwarding. Specifically:

[0080] User registration process:

[0081] like Figure 3 As shown, the user registration process of the present invention includes the following detailed steps:

[0082] S301: The user equipment sends a registration request to the connected MAS, i.e., PLMS. The request message contains information such as user ID, equipment type, service requirements, access technology type, and timestamp;

[0083] S302: After receiving the request, the PLMS allocates an IP prefix address to the user, sends a Router Advertisement (RA) message to inform the user of the IP prefix and the MAS information to which the user is connected, and dynamically selects the most suitable LMA for registration based on the LMA list predicted by the ephemeris information;

[0084] S303: PLMS sends a Proxy Binding Update (PBU) message to the selected master LMA. The message content includes user information, user IP, satellite ID, satellite IP, timestamp, etc.

[0085] S304: After receiving the PBU message, the master LMA performs the following operations:

[0086] a) Verify user identity and request legitimacy;

[0087] b) Create a user BCE and record information such as user ID, user IP address, IP address of the user connecting to MAS, current location, service parameters, etc.

[0088] S305: The master LMA sends a Proxy Binding Acknowledgement (PBA) message to the PLMS. The message contains the network parameters assigned to the user;

[0089] The user equipment completes the network configuration and is ready to start data communication.

[0090] S306: The master LMA synchronizes user information data with other LMAs.

[0091] During the entire registration process, the system uses a secure encryption mechanism to protect user privacy and data security.

[0092] User switching process:

[0093] like Figure 4 As shown, the user switching process of the present invention includes the following detailed steps:

[0094] S401: The user equipment triggers a handover process according to a handover strategy and attaches to a new satellite;

[0095] S402: The user equipment sends a handover request to the new MAS (nMAS). The request message contains information such as user ID, user IP, and current serving satellite IP;

[0096] S403: nMAS sends an RA message to the user equipment. The message contains updated network configuration information, such as new routing parameters, etc.

[0097] S404: nMAS sends a PBU message to the user PLMS, the previous MAS (pMAS), and the LMA in the current PMIPv6 domain. The message content includes the user ID, user IP, nMAS ID and IP address, timestamp, etc.

[0098] S405: After receiving the PBU message, the PLMS performs the following operations:

[0099] a) Update user BCE;

[0100] b) Send a PBA message to nMAS.

[0101] S406: After receiving the PBU message, the pMAS performs the following operations:

[0102] a) Unbinding from the user;

[0103] b) Send a PBA message to nMAS.

[0104] S407: After receiving the PBU message, the current master LMA performs the following operations:

[0105] a) Update BCE and record new service satellite information; satellites move according to the predetermined orbit, and the spatial position of the satellite at any time and the topological relationship between satellites can be known based on the ephemeris;

[0106] b) Send a PBA message to nMAS, including the user's latest network parameters.

[0107] S408: The current LMA sends a user information synchronization message to other LMAs. This ensures that during the user's movement, the relevant LMAs can obtain the latest status of the user in a timely manner;

[0108] S409: The user completes network reconfiguration.

[0109] LMA synchronization mechanism:

[0110] To ensure consistency between distributed LMAs, when the user status changes (such as registration, satellite switching, etc.), information synchronization is required between LMAs. The LMA synchronization mechanism of the present invention includes the following detailed steps:

[0111] S501: Synchronous triggering conditions:

[0112] New user registration;

[0113] Users switch satellites;

[0114] User logout;

[0115] BCE is updated regularly;

[0116] S502: When the user switches to nMAS, nMAS sends a PBU message to the LMA in the current PMIPv6 domain.

[0117] S503: After receiving the PBU message, the current LMA performs the following operations:

[0118] a) Update the local user BCE;

[0119] b) Generate a synchronization message containing the following information:

[0120] User ID, user IP;

[0121] The user's current IP address for accessing the satellite (new CoA);

[0122] The user's geographical location (which can be the satellite's coverage area or the estimated user location);

[0123] S504: The current LMA sends a synchronization message to other LMAs;

[0124] S505: After receiving the synchronization message, the other LMAs perform the following operations:

[0125] a) Verify the authenticity and timeliness of the message;

[0126] b) Update user information in the local cache;

[0127] c) If it is predicted that the user may move to the service area of ​​this LMA, necessary resources are reserved.

[0128] Data forwarding process:

[0129] This embodiment includes two parts: ground network traffic forwarding and inter-satellite terminal traffic forwarding.

[0130] like Figure 5 As shown, the ground network traffic data forwarding process of the present invention includes the following detailed steps:

[0131] S601: When target user 1 in the area where LMA1 is located accesses the ground service network in the area where LMA4 is located by accessing MAS1, the ground service network generates a data packet:

[0132] Source address: server IP address;

[0133] Destination address: IP address of target user 1;

[0134] S602: The data packet arrives at the associated LMA4 through routing;

[0135] S603: After receiving the data packet, LMA4 performs the following operations:

[0136] Query the local user BCE to obtain the latest location information of the target user 1, including the IP address of the access MAS.

[0137] S604: LMA4 uses tunnel encapsulation technology to process data packets:

[0138] a) Outer IP header:

[0139] Source IP address: IP address of source LMA4;

[0140] Target IP address: IP address connected to MAS1;

[0141] b) Inner IP header (original data packet):

[0142] Source IP address: the sender's IP address;

[0143] Target IP address: IP address of target user 1;

[0144] S605: LMA4 sends the encapsulated data packet using the data tunnel between the target user 1 and MAS1;

[0145] S606: MAS1 accessed by target user 1 receives the data packet, decapsulates the outer IP header, checks the destination address of the inner IP header, and then transmits the original data packet to target user 1;

[0146] S607: Target user 1 receives the data packet. From the perspective of target user 1, what it receives is the original data packet directly sent to its IP address, and the whole process is transparent to the user device.

[0147] The inter-satellite terminal traffic data forwarding process of the present invention is exemplified as follows: a communication user 2 located in the area where LMA5 is located initiates communication with a target user 1 located in the area where LMA1 is located. Figure 6 As shown, it is assumed that the PLMS of communication user 2 is MAS3, and its current access satellite is MAS4; the PLMS of target user 1 is MAS0, and its current access satellite is MAS1; during the communication process, the access satellite of target user 1 is switched from MAS1 to MAS2, including the following detailed steps:

[0148] S608: Communication user 2 sends a data packet to the PLMS of target user 1, namely MAS0, according to the IP address of target user 1. PLMS first finds out the current access location MAS1 of target user 1, then establishes a tunnel and forwards it to the current MAS1 of target user 1 through the tunnel:

[0149] Outer IP header:

[0150] Source IP address: IP address of MAS0;

[0151] Target IP address: IP address of MAS1;

[0152] Inner IP header (original data packet):

[0153] Source IP address: IP address of communication user 2;

[0154] Target IP address: IP address of target user 1;

[0155] S609: MAS1 currently accessed by target user 1 receives the data packet, decapsulates the outer IP header, checks the destination address of the inner IP header, and then transmits the original data packet to target user 1;

[0156] S610: During the communication process between target user 1 and communication user 2, user 1 switches from currently accessing MAS1 to MAS2;

[0157] S611: MAS2 detects the access of target user 1 and sends a location update message to MAS0 where target user 1 initially registered, including:

[0158] User ID, user IP;

[0159] The IP address of the new MAS;

[0160] S612: MAS0 receives the location update message and updates its user BCE;

[0161] S613: A bidirectional tunnel is established between MAS0 and MAS2;

[0162] S614: If MAS0 is currently receiving a data packet destined for the user, it will forward the data packet to MAS2 through the newly established tunnel:

[0163] Outer IP header:

[0164] Source IP address: IP address of MAS0;

[0165] Target IP address: IP address of MAS2;

[0166] Inner IP header (original data packet):

[0167] Source IP address: IP address of communication user 2;

[0168] Target IP address: IP address of target user 1;

[0169] S615: MAS2 receives the data packet forwarded through the tunnel, decapsulates it and delivers it to the target user 1;

[0170] Target user 1 initiates communication with communication user 2. The inter-satellite data packet forwarding process is similar:

[0171] S616: Target user 1 sends a data packet to the PLMS of communication user 2, which is MAS3 in this example. MAS3 finds out the access location MAS4 of communication user 2 at this time, establishes a tunnel and forwards it to communication user 2 to access MAS4.

[0172] S617: MAS4 currently accessed by communication user 2 receives the data packet, decapsulates the outer IP header, checks the destination address of the inner IP header, and transmits the original data packet to communication user 2.

[0173] A key feature of the present invention is to use the PMIPv6 protocol to maintain the stability of the user's IP address. In traditional mobile IP methods and systems, when a user (User Equipment, UE) switches to access a satellite, its IP address usually needs to be changed, which may cause communication interruption and performance degradation. In this regard, the present invention supports users to maintain the same IP address when switching between different access MASs through distributed PMIPv6 protocol deployment. The user registers with the MAS to allocate a home address (HoA) to the user terminal. When the user switches the MAS, the switched MAS sends a proxy binding update message (ProxyBinding Update, PBU) to the LMA. The LMA maintains and manages the user's location information, maintains the continuity of the user's IP address, and only updates the MAS address bound to the user. The data packet is sent to the user's current location through tunnel technology. For the user, his IP address remains unchanged. This mechanism ensures that when the user switches access points in a high-speed low-orbit satellite network, the IP address can be kept stable, thereby achieving seamless communication and reducing switching delays and data loss.

[0174] Through the above detailed implementation, the PMIPv6-based satellite network mobility management method and system of the present invention can effectively support large-scale, highly dynamic satellite communication networks. The method and system ensure the correct routing and forwarding of data packets, and at the same time, through timely LMA information synchronization, ensure that users can still obtain continuous communication services under the conditions of high-speed movement and frequent satellite switching.

[0175] The method and system of the present invention improve the scalability and reliability of the system, and are particularly suitable for future large-scale LEO satellite constellation systems. By sharing the latest location information of users between LMAs, the system can quickly respond to the movement of users, thereby achieving efficient mobility management.

Claims

1. A satellite network mobility management system based on PMIPv6, characterized in that: The system includes a location mobile anchor point LMA, a ground station, a ground service network, and a mobile access satellite MAS; wherein: Each LMA serves as a boundary node for the interaction between the ground service network and the satellite network. It is responsible for maintaining global user information and network status, managing user mobility, storing user location and service information, forwarding data using the tunnel mechanism, selecting the optimal route, and achieving information synchronization and coordination between LMAs. As the key node for the interconnection between the satellite network and the ground service network, the ground station is responsible for the signaling interaction and data transfer between the satellite and the ground. In each ground station management area, only one ground station is set up and LMA is deployed in the area. The ground service network is responsible for processing user ground data services; Each MAS serves as a user access satellite of the satellite network and is responsible for the access authentication of the terminal user. As a router, it configures the network segment for the terminal user to access and publishes the network segment route to the network. It allocates an IP address to the user when the user registers and dynamically selects the optimal LMA for user information management based on the ephemeris information. At the same time, the MAS allocates a home address HoA to the user terminal, manages the terminal location information and session connection information within the coverage area, provides data forwarding function when the terminal moves and switches, and interacts with the LMA for mobility-related signaling. The MAS to which the user initially registers and accesses serves as the user's proxy location mobile satellite PLMS, and is responsible for tunnel establishment and cache establishment when the user forwards inter-satellite terminal traffic.

2. The satellite network mobility management system based on PMIPv6 according to claim 1, characterized in that: Each LMA is a boundary node for the interaction between the ground service network and the satellite network. It is responsible for maintaining global user information and network status, managing user mobility, storing user location and service information, forwarding data using a tunnel mechanism, selecting the optimal route, and achieving information synchronization and coordination between LMAs. Specifically, it includes: Maintain and manage the user's binding cache entry BCE, record user ID, user IP address, user access MAS, user location, and user service parameters; Use tunneling mechanism to forward data packets from ground service network or other users to the access MAS of target users; Synchronize user BCE information with other LMAs through dedicated links.

3. The satellite network mobility management system based on PMIPv6 according to claim 1, characterized in that: Each MAS serves as a user access satellite of the satellite network, is responsible for the access authentication of the terminal user, allocates an IP address to the user when the user registers, and dynamically selects the optimal LMA to manage user information based on the ephemeris information, specifically including: Receive registration requests initiated by users, allocate the same network segment IP address of the MAS to the users, and send routing announcements RA; Predict the user's region based on its own ephemeris, and select the optimal LMA to send a proxy binding update message PBU; Establish a bidirectional tunnel with LMA for user data packets to be forwarded; The MAS where the user initially registers is defined as the user's proxy location mobile satellite PLMS, which is responsible for establishing tunnels and caches when forwarding user inter-satellite terminal traffic.

4. The satellite network mobility management system based on PMIPv6 according to claim 1, characterized in that: The deployment of LMA includes: At least one LMA is deployed in each ground station management area. A distributed database for storing user information is created on the LMA, and a data synchronization mechanism is established between each LMA.

5. A PMIPv6-based satellite network mobility management method, the method running on the PMIPv6-based satellite network mobility management system according to any one of claims 1 to 4, characterized in that: The PMIPv6-based satellite network mobility management system dynamically divides PMIPv6 domains according to LMAs in the ground station management area. A PMIPv6 domain consists of a main LMA and all MASs managed by it in the current time slice. The distributed PMIPv6 protocol deployment is used to support users to maintain the same IP address when switching between different access MASs, and the information synchronization mechanism between LMAs is used to ensure accurate data routing and continuous communication when users move at high speed and frequently switch satellites, thereby realizing the mobility management process including user registration, user switching, LMA synchronization mechanism, ground network traffic forwarding and inter-satellite terminal traffic forwarding, which specifically includes: 1) LMA deployment: deploy multiple LMAs, and deploy LMAs in the area where the ground station is located as boundary nodes that interact with the ground service network. Define the ground station management area based on user density, communication requirements, and network load. Each ground station management area has only one ground station and at least one LMA deployed; 2) User registration: MAS receives user registration request, assigns home address HoA to the user, and serves as the MAS for initial registration of the user, called PLMS, acting as the proxy location mobile satellite of the user; at the same time, PLMS selects the best LMA as the master LMA to send PBU message, the master LMA creates BCE, replies to the proxy binding confirmation message PBA, and synchronizes BCE to other LMAs; 3) User switching: define the MAS accessed at the last moment as pMAS, the newly accessed MAS as nMAS, and the MAS that the user initially registers as PLMS; when the user switches from pMAS to nMAS, nMAS sends a PBU message to pMAS and PLMS; pMAS releases the binding relationship, PLMS updates BCE, nMAS selects the optimal LMA as the main LMA and sends a PBU message; the main LMA updates BCE and synchronizes with other LMAs; 4) LMA synchronization mechanism: A secure dedicated link is established between each LMA to update the synchronization message. When the user's BCE changes, the LMA in the current management area updates the user information; the current master LMA sends a user information synchronization message to other LMAs; other LMAs receive the synchronization message and update the BCE; 5) Ground network traffic forwarding: The ground service network sends the data packet requested by the user to the optimal LMA in the area. The LMA queries the BCE and forwards it to the user's latest access MAS through the tunnel, and then forwards it to the user; 6) Inter-satellite terminal traffic forwarding: When a communication user sends a data packet to a target user, the data packet is first sent to the target user's PLMS. The target user's PLMS queries the target user's current location based on the BCE, and then uses the tunnel mechanism to forward it to the target user's latest access MAS, and then forwards it to the target user.

6. The method for satellite network mobility management based on PMIPv6 according to claim 5, characterized in that: The LMA deployment specifically includes: Establish secure communication links between LMAs; Initialize the LMA user information database.

7. The method for satellite network mobility management based on PMIPv6 according to claim 5, characterized in that: The detailed steps of the user switching are as follows: When a user switches from a previously connected pMAS to an nMAS: nMAS sends a PBU message to pMAS; pMAS releases the binding relationship with the user and replies a PBA message to nMAS; nMAS sends PBU message to the user's PLMS; PLMS updates the user's BCE and replies to the PBA message; nMAS updates its own BCE and selects the primary LMA based on the ephemeris prediction data, and sends a PBU message; The master LMA updates the BCE, replies to the PBA message, and synchronizes the updated BCE to other LMAs.

8. The method for satellite network mobility management based on PMIPv6 according to claim 5, characterized in that: The LMA synchronization mechanism updates synchronization messages by establishing a secure dedicated link between each LMA. The specific synchronization process includes: The current master LMA generates a synchronization message when the user's BCE changes, including user registration, switching, deregistration and BCE regular update, which will cause the user's BCE to change. The synchronization message contains the user ID, IP address, access MAS, and location; The current master LMA sends synchronization messages to all other LMAs; After receiving the synchronization message, other LMAs update their local BCEs.

9. The method for satellite network mobility management based on PMIPv6 according to claim 5, characterized in that: The ground network traffic forwarding includes: The ground service network selects the optimal distributed LMA to send data packets based on the estimated routing path and load conditions; LMA processes data packets using tunnel encapsulation technology based on cache information; The LMA forwards the encapsulated data packet to the target user’s latest access MAS; MAS decapsulates the data packet and forwards it to the target user.

10. The method for satellite network mobility management based on PMIPv6 according to claim 5, characterized in that: The inter-satellite terminal traffic forwarding includes: The communication user sends a data packet to the target user PLMS; The target user's PLMS queries the target user's current location information; The target user's PLMS forwards the data packet to the target user's latest access MAS through the intersatellite link using a tunneling method; The target user newly accesses the MAS to decapsulate the data packet and forward the data packet to the target user; At the same time, the target user also uses the same forwarding process to send data packets to the communication user, and tunnel forwarding is performed through the communication user's PLMS.

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