Multilayer heterogeneous satellite network architecture and satellite selection access method

Abstract

The invention provides a multi-layer heterogeneous satellite network architecture and a satellite selection access method. The multi-layer heterogeneous satellite network architecture is composed of a GEO satellite layer, an IGSO satellite layer and an LEO satellite layer. The satellite selection access method comprises the following steps: determining an accessible satellite set according to a terminal position and a satellite ephemeris in the multi-layer heterogeneous satellite network architecture; dynamically setting a weight factor according to a terminal service demand and a QoS demand; calculating real-time positions of satellites in the accessible satellite set, and calculating a transmission distance and service time between each satellite and the terminal according to a satellite ephemeris; acquiring satellite used resources and all resource sets; calculating a weighted value of each satellite in an accessible satellite set according to the weight factor, the transmission distance, the service time and the satellite resource information; and selecting the target satellite with the maximum weighted value as an access node. Therefore, the method can provide a larger coverage range and stable link connection, and improves the system access success rate and the system robustness.

Description

Technical Field

[0001] The present invention relates to the field of satellite communication technology, and in particular to a multi-layer heterogeneous satellite network architecture and a satellite selection and access method. Background Art

[0002] Single-layer satellite networks have a simple structure. Under reasonable constellation design, the relative topology between satellites remains almost unchanged or changes slightly, and the management, control, and routing calculation complexity are lower. Compared with single-layer satellite networks, multi-layer satellite networks have the following advantages:

[0003] 1) Multi-layer heterogeneous satellite communication networks deploy satellites at different orbital altitudes. Satellite networks at different layers have different channel characteristics such as path loss, delay, and Doppler shift, which can provide users with differentiated business services with different rates and QoS.

[0004] 2) Satellite networks at different altitudes can adopt different communication systems and access mechanisms to provide access services with different access and switching characteristics and different access capacities for multiple users.

[0005] 3) Constellations with different orbit types, different orbit altitudes and inclinations can cover different areas, and multi-layer satellite networks can form complementary coverage to meet coverage needs in different regions around the world.

[0006] 4) A single-layer low-orbit satellite network has many satellites on each path, resulting in a large cumulative processing delay. By adopting a multi-layer satellite network, relays can be made through high- and medium-orbit satellites, significantly improving the satellite network delay.

[0007] 5) A single-layer satellite network can only search for alternative paths within the same layer. Not only are there fewer alternative paths, but when subjected to physical or electromagnetic attacks, they are easily compromised by the same attack methods, resulting in low robustness. When using a multi-layer satellite network, alternative paths can be selected at different layers. Due to the differences in orbital altitudes, communication systems, etc., different layers are not easily vulnerable to attacks by the same means, resulting in higher robustness.

[0008] Compared to single-layer satellite networks, multi-layer satellite networks offer a more complex structure, more flexible topology, wider coverage, support for a wider range of services, and more efficient and robust access and routing applications, making them highly valuable for research and application. However, due to the relative motion between layers, multi-layer heterogeneous networks experience more complex topologies and inter-layer connectivity. Consequently, user access, routing calculations, and management and control in these networks are more challenging.

[0009] Existing multi-layer satellite networks typically employ a multi-layer LEO satellite network architecture, a hybrid medium- and high-orbit (MEO) or "GEO + LEO" multi-layer network architecture. These architectures combine the characteristics of satellites at different layers and altitudes, offering complementary advantages and providing users with diverse business services. However, these architectures are designed for specific application scenarios and services and present the following challenges:

[0010] 1) In terms of global user coverage, although it can cover every corner of the world, the global user and business distribution is not uniform. In the low- and medium-latitude land areas where business volume is concentrated, satellite resources are seriously insufficient, but in the ocean and high-latitude areas, satellite resources are obviously in excess.

[0011] 2) In terms of diversified service capabilities, GEO satellites can provide users with stable connections, but due to their high link loss, high-speed broadband services require high power and large bandwidth, which is not conducive to terminal miniaturization and cannot meet the needs of low-latency services. LEO satellites, on the other hand, have low path loss and short latency, making them suitable for broadband, high-speed, and low-latency services. However, their short overhead time requires users to frequently switch between beams and satellites, requiring carefully designed switching and routing mechanisms to ensure continuous and reliable service for users. Existing mechanisms fail to integrate the characteristics and advantages of high and low orbit satellites with services to provide reasonable access and routing scheduling. Summary of the Invention

[0012] In response to the above-mentioned defects, the purpose of the present invention is to provide a multi-layer heterogeneous satellite network architecture that takes into account coverage characteristics, access characteristics, and transmission performance, and can meet the diverse functional and performance requirements of users, as well as a satellite selection and access method under this architecture. The method can improve the system access success rate and system robustness.

[0013] In order to achieve the above technical effects, on the one hand, the present invention provides a multi-layer heterogeneous satellite network architecture, including:

[0014] A GEO satellite layer is composed of a plurality of geostationary orbit satellites, wherein the geostationary orbit satellites are distributed over a preset area according to a preset distribution rule, and inter-satellite links are established between the geostationary orbit satellites;

[0015] The IGSO satellite layer is composed of multiple inclined geosynchronous orbit satellites with an orbital inclination of 70 degrees, which are evenly distributed in the same orbit and have inter-satellite links established between the inclined geosynchronous orbit satellites;

[0016] The LEO satellite layer includes a polar-orbiting constellation covering the polar regions and a Walker constellation covering mid- and low-latitudes; the polar-orbiting constellation has 12 orbits, each containing 6 LEO satellites at an orbital altitude of 1250 km; the Walker constellation has 12 orbits, each containing 9 LEO satellites, with an inclination of 55 degrees and an orbital altitude of 1000 km;

[0017] A microwave inter-satellite link is established between the GEO satellite layer and the LEO satellite layer, and an inter-satellite link is established between the IGSO satellite layer and the LEO satellite layer; and there is no direct inter-satellite link connection between the polar orbit constellation and the Walker constellation.

[0018] Optionally, the GEO satellite layer is composed of at least 5 geostationary orbit satellites, and 3 of the geostationary orbit satellites are evenly distributed over the equator, and at least two of the geostationary orbit satellites are distributed over a predetermined territory and surrounding areas.

[0019] On the other hand, the present invention also provides a satellite selection and access method based on the above-mentioned multi-layer heterogeneous satellite network architecture, comprising the steps of:

[0020] Calculating a connection relationship between each satellite and the terminal according to the terminal position and satellite ephemeris in the multi-layer heterogeneous satellite network architecture, and determining a set of accessible satellites based on the connection relationship;

[0021] Dynamically set weight factors according to terminal service requirements and QoS requirements; wherein the weight factors include transmission distance weight factor, satellite resource weight factor and service time weight factor;

[0022] Calculating the real-time positions of satellites in the accessible satellite set, and calculating the transmission distance and service time between each satellite and the terminal based on the satellite ephemeris;

[0023] Obtaining the used resources of the satellite and the total resource set according to the usage of the resources of each satellite in the accessible satellite set;

[0024] Calculating a weighted value for each satellite in the accessible satellite set according to the weight factor, the transmission distance, the service time, and satellite resource information;

[0025] The target satellite with the largest weighted value is selected as the access node, and a same-layer or cross-layer backup satellite is prepared.

[0026] Optionally, the weighted value of each satellite is calculated based on the following formula:

[0027]

[0028] T max=max{T s},s∈S;

[0029] T m =min(T req ,T max );

[0030]

[0031] D min =min{D s},s∈S;

[0032] Among them, C s is the weighted value of satellite s after considering transmission distance, available resources and service time; S is the set of accessible satellites; α is the transmission distance weight factor; β is the satellite resource weight factor; γ is the service time weight factor; D min The minimum transmission distance between the terminal and all satellites; D s is the transmission distance between the terminal and the satellite s; All resources for satellite s; is the used resources of satellite s; R max is the maximum value of resources among all satellites; T s T is the service time of satellite s to the terminal; max T is the maximum service time of all satellites to the terminal; req The service time required for the terminal; T m It is the minimum of the required service time for the terminal and the maximum service time of all satellites to the terminal.

[0033] Optionally, the weighted value is max s∈S C s The target satellite is determined as the access node.

[0034] Optionally, the dynamic setting rules of the weight factor include:

[0035] If the service is determined to be a delay-sensitive service based on the terminal service requirements and QoS requirements, increasing the transmission distance weight factor;

[0036] If the service is determined to be a high-resource-demand service based on the terminal service demand and QoS requirements, the satellite resource weight factor is increased;

[0037] If it is determined to be a long connection stable service based on the terminal service requirements and QoS requirements, the service time weight factor is increased.

[0038] Optionally, preparing the same-layer or cross-layer backup satellite includes:

[0039] A same-layer multiple coverage strategy or a multi-layer multiple coverage strategy is used to select backup satellites, and rapid switching in a strong interference environment is achieved through spatial redundancy.

[0040] This invention leverages the advantages of GEO satellites, IGSO satellites, polar-orbiting constellations, and Walker constellations to establish a multi-layered, heterogeneous satellite network integrating GEO, IGSO, polar-orbiting, and Walker constellations. This network leverages these advantages to provide diverse services to users worldwide. In this multi-layered, heterogeneous satellite network, satellites on each layer have varying altitudes and speeds relative to the ground, resulting in varying path loss, latency, and service times. Consequently, the bandwidth, data rate, real-time performance, service duration, and inter-beam / inter-satellite handoff frequency offered to users vary. Therefore, it is necessary to select the most suitable satellite to provide services based on the user's specific service needs and QoS requirements. In this regard, the present invention further studies the multi-layer heterogeneous satellite network architecture and establishment process based on global coverage requirements and diversified business requirements, and establishes a multi-layer heterogeneous satellite network satellite selection and access optimization model for user business and QoS requirements based on the constellation operation status, satellite-ground connection topology, regional interference situation, historical access data, link quality assessment and satellite service capabilities. The satellites are optimized and scheduled and configured through the satellite selection and access optimization algorithm, thereby improving the system access success rate and system robustness while meeting user business requirements and QoS requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of the multi-layer heterogeneous satellite network architecture provided by an embodiment of the present invention;

[0042] Figure 2 A flowchart of the steps of the satellite selection and access method provided in another embodiment of the present invention;

[0043] Figure 3 A flow chart for designing the satellite network space segment of the multi-layer heterogeneous satellite network architecture of the present invention;

[0044] Figure 4 A 3D view of the interconnected model of the multi-layer heterogeneous satellite network architecture of the present invention;

[0045] Figure 5 A 2D view of the interconnection model of the multi-layer heterogeneous satellite network architecture of the present invention;

[0046] Figure 6 This is a control plane satellite selection and clustering block diagram of the satellite access method of the present invention;

[0047] Figure 7 This is a schematic block diagram of the satellite selection process of the satellite access method of the present invention;

[0048] Figure 8A comparison chart of access success probabilities under different traffic densities between an existing single-layer LEO constellation and the multi-layer heterogeneous satellite network architecture described in an embodiment of the present invention;

[0049] Figure 9 This is a comparison chart of the average number of switching times under different traffic densities between the existing single-layer LEO constellation and the multi-layer heterogeneous satellite network architecture described in an embodiment of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0051] It should be noted that references to "one embodiment," "an embodiment," "an example embodiment," etc., in this specification indicate that the described embodiment may include specific features, structures, or characteristics, but not every embodiment must include these specific features, structures, or characteristics. Furthermore, such references do not necessarily refer to the same embodiment. Furthermore, when specific features, structures, or characteristics are described in conjunction with an embodiment, whether or not explicitly described, it is understood that incorporating such features, structures, or characteristics into other embodiments is within the knowledge of those skilled in the art.

[0052] In addition, certain words are used in the specification and subsequent claims to refer to specific components or parts. It should be understood by those with ordinary knowledge in the relevant field that manufacturers may use different nouns or terms to refer to the same component or part. This specification and subsequent claims do not use differences in names as a way to distinguish components or parts, but rather use differences in the functions of components or parts as the criteria for distinction. The words "including" and "comprising" mentioned throughout the specification and subsequent claims are open-ended terms and should be interpreted as "including but not limited to". In addition, the word "connect" here includes any direct and indirect electrical connection means. Indirect electrical connection means include connection through other devices.

[0053] Satellite networks at different levels are tailored to different business needs and terminal form factors, meeting varying coverage requirements. GEO satellites offer wide coverage and stable links. IGSO satellites can cover high, medium, and low latitudes, including the polar regions, in different time periods, providing wide-area coverage and relatively stable connections. Polar-orbiting LEO satellites can cover high latitudes and even the polar regions, offering low link loss and short transmission latency, making them suitable for high-speed broadband and latency-sensitive services. The Walker constellation, with its lower inclination, offers better coverage of mid- and low-latitude regions, concentrating superior satellite resources in areas with high traffic volume and providing high-speed, low-latency services.

[0054] To this end, the present invention leverages the advantages of GEO satellites, IGSO satellites, polar-orbiting constellations, and Walker constellations to establish a multi-layered, heterogeneous satellite network integrating GEO, IGSO, polar-orbiting, and Walker constellations. This leverages these advantages to provide diverse services to users worldwide. In this multi-layered, heterogeneous satellite network, the satellites on each layer have different altitudes and speeds relative to the ground, resulting in varying path loss, latency, and service times. Consequently, the bandwidth, data rate, real-time performance, service duration, and inter-beam / inter-satellite handoff frequency that can be provided to users vary. Therefore, it is necessary to select the most suitable satellite to provide services based on the user's specific service needs and QoS requirements. In this regard, the present invention further studies the multi-layer heterogeneous satellite network architecture and establishment process based on global coverage requirements and diversified business requirements, and establishes a multi-layer heterogeneous satellite network satellite selection and access optimization model for user business and QoS requirements based on the constellation operation status, satellite-ground connection topology, regional interference situation, historical access data, link quality assessment and satellite service capabilities. The satellites are optimized and scheduled and configured through the satellite selection and access optimization algorithm, thereby improving the system access success rate and system robustness while meeting user business requirements and QoS requirements.

[0055] First, we analyze the factors affecting the design of multi-layer heterogeneous satellite network architecture. The main factors that need to be considered are:

[0056] 1) Coverage requirements. A multi-layer heterogeneous network must first determine its coverage area based on coverage requirements. Large-area coverage requires GEO / IGSO satellites, polar region coverage requires polar-orbiting constellations, and enhanced coverage in mid- and low-latitudes requires Walker constellations with small to medium orbital inclinations.

[0057] 2) Service requirements. For narrowband voice and low-rate data services, GEO / IGSO satellites can meet these requirements. For large terminals, GEO / IGSO satellites can also meet certain broadband and high-speed service requirements, but at a higher cost. For broadband and high-speed services, low-orbit satellites with lower path loss can be selected to provide services.

[0058] 3) QoS requirements. User QoS requirements are also a key consideration in satellite network architecture design. For broadband, high-speed, real-time services, low-orbit constellations are used; for narrowband, non-time-sensitive services, high- and medium-orbit constellations such as GEO / IGSO satellites can be used.

[0059] 4) Terminal form factor requirements. Terminal form factor is also a key factor in satellite network architecture design. For systems requiring terminal miniaturization, GEO / IGSO satellites have high link loss and low signal-to-noise ratio, requiring larger antennas, making it difficult to meet these requirements. Low-orbit satellites, on the other hand, have low link loss and high signal-to-noise ratio, enabling communication at lower power. Miniaturized antennas and RF components can be used, meeting these requirements.

[0060] Therefore, in order to support global coverage and enhanced coverage of key areas in mid- and low-latitudes, and to meet the needs of different types of users, QoS requirements and terminal form requirements, the present invention designs a multi-layer heterogeneous satellite network architecture based on GEO satellites, IGSO satellites and LEO constellations to meet the needs of stable connection, terminal miniaturization, polar region coverage, mid- and low-latitude region coverage, etc. The design process of the multi-layer heterogeneous satellite network architecture is as follows: Figure 3 shown.

[0061] Figure 1 A multi-layer heterogeneous satellite network architecture provided by an embodiment of the present invention is shown, including a GEO satellite layer, an IGSO satellite layer, and a LEO satellite layer, wherein:

[0062] The GEO satellite layer is composed of multiple geostationary orbit satellites, which are distributed over a preset area according to a preset distribution rule, and inter-satellite links are established between each geostationary orbit satellite; the IGSO satellite layer is composed of multiple inclined geosynchronous orbit satellites with an orbital inclination of 70 degrees, evenly distributed on the same orbit, and inter-satellite links are established between the inclined geosynchronous orbit satellites; the LEO satellite layer includes a polar constellation covering the polar regions and a Walker constellation covering mid- and low-latitudes; the polar constellation has 12 orbits, each containing 6 LEO satellites, with an orbital altitude of 1250km; the Walker constellation has 12 orbits, each containing 9 LEO satellites, with an inclination of 55 degrees and an orbital altitude of 1000km; a microwave inter-satellite link is established between the GEO satellite layer and the LEO satellite layer, and an inter-satellite link is established between the IGSO satellite layer and the LEO satellite layer; there is no direct inter-satellite link connection between the polar constellation and the Walker constellation.

[0063] The satellite network space segment interconnection model of the multi-layer heterogeneous satellite network architecture of this embodiment is as follows: Figures 4 and 5 As shown, it includes three components: the GEO satellite backbone network, the IGSO constellation, and the LEO constellation composed of the LEO polar orbit constellation and the LEO inclined orbit constellation. The space segment satellite network is responsible for the long-distance transmission of space-based data. When ground stations are limited, global communication can be achieved through space-based networking.

[0064] In a specific embodiment, the multi-layer heterogeneous satellite network architecture is configured as follows:

[0065] 1) The GEO satellite layer consists of five geostationary orbit satellites, three of which are evenly distributed over the equator, and two of which are located over a predetermined territory and surrounding areas. For example, one of the equatorial GEO satellites is located over a predetermined territory, and the other two are located to the left and right of the GEO satellite over the territory, with a longitude separation of approximately 15 degrees. Each GEO satellite has an intersatellite link with two adjacent GEO satellites.

[0066] 2) The IGSO satellite layer consists of three IGSO satellites with an orbital inclination of 70 degrees, evenly distributed in the same orbit. Adjacent IGSO satellites have inter-satellite links (ISLs). However, there are no ISLs between IGSO satellites and GEO satellites.

[0067] 3) The LEO satellite layer consists of two LEO constellations: the polar LEO_P constellation and the Walker LEO_W constellation. LEO_P consists of 12 orbits, each with 6 satellites, at an altitude of 1250 km, a phase factor of 6, and a beam coverage of 53.5°. LEO_W consists of 12 orbits, each with 9 satellites, in an inclined orbit with an inclination of 55°, at an altitude of 1000 km, a phase factor of 6, and a beam coverage of 56.5°. Each LEO satellite has four intersatellite links: two in-orbit links and two out-of-orbit links. There is no direct intersatellite link connection between LEO_P and LEO_W.

[0068] There will tentatively be microwave intersatellite links between GEO satellites and LEO satellites, and there will tentatively be intersatellite links between IGSO satellites and LEO satellites.

[0069] When users face multi-layer heterogeneous satellite networks, on the one hand, they can select a single-layer satellite network access suitable for themselves from the multi-layer satellite network according to the adaptability of their own communication system, that is, a user terminal with single-layer access; on the other hand, for those who can adapt to the multi-layer satellite network system, they need to select the most suitable shell satellite access from the multi-layer satellite network according to the access strategy.

[0070] The following introduces the satellite selection access strategy further provided by the present invention.

[0071] For single-layer satellite networks, terminals are selected mainly based on service QoS requirements, constellation topology dynamics and connectivity, satellite resources, dwell time, link quality (path loss, rain attenuation, interference and electromagnetic environment are reflected in link quality), satellite load, historical data, etc.

[0072] Satellite selection for access innovates terminal access methods, but also introduces issues such as link optimization and resource coordination. The clustered communication architecture of a multi-layer heterogeneous network based on satellite selection can be divided into the following three parts:

[0073] 1. Candidate nodes, efficient access: Based on the injection of multi-layer satellite network preferred node plans and dynamic satellite-ground topology information, the terminal clearly understands the satellite-ground service relationship and selects multiple candidate access nodes, enabling efficient and rapid terminal access through the candidate nodes.

[0074] 2. Optimize access and increase capacity: Optimize satellite selection based on constellation dynamics and the electromagnetic landscape of satellite-to-ground links. Leverage multi-layer, overlapping coverage to plan optimal multi-satellite access. Develop a joint multi-satellite-to-ground link handling strategy based on interference predictions to optimize access nodes and implement backup, thereby improving potential interference mitigation capabilities and capacity.

[0075] 3. Resource coordination and link optimization: Based on the resource planning of each terminal and satellite, taking into account the robustness and security requirements of the satellite-to-ground link, multi-satellite resources are coordinated and scheduled to guide terminals to build satellite-to-ground links and achieve robust satellite-to-ground data transmission.

[0076] In response to the above optimization problem, the present invention provides a satellite access selection method in another embodiment.

[0077] See also Figure 2 The satellite access selection method is based on the multi-layer heterogeneous satellite network architecture described in the above embodiment, and includes the following steps:

[0078] S101: Calculate the connection relationship between each satellite and the terminal according to the terminal position and the satellite ephemeris in the multi-layer heterogeneous satellite network architecture, and determine the accessible satellite set based on the connection relationship.

[0079] S102: Dynamically set weight factors according to terminal service requirements and QoS requirements; wherein the weight factors include a transmission distance weight factor, a satellite resource weight factor, and a service time weight factor.

[0080] S103: Calculate the real-time positions of satellites in the accessible satellite set, and calculate the transmission distance and service time between each satellite and the terminal based on the satellite ephemeris.

[0081] S104: According to the usage of each satellite resource in the accessible satellite set, the used satellite resources and the entire resource set are obtained.

[0082] S105: Calculate the weighted value of each satellite in the accessible satellite set based on the weight factor, transmission distance, service time, and satellite resource information. Specifically, the weighted value of each satellite is calculated based on the following formula:

[0083]

[0084] T max =max{T s},s∈S;

[0085] T m =min(T req ,T max );

[0086]

[0087] D min =min{D s},s∈S;

[0088] Among them, C s is the weighted value of satellite s after considering transmission distance, available resources and service time; S is the set of accessible satellites; α is the transmission distance weight factor; β is the satellite resource weight factor; γ is the service time weight factor; D min The minimum transmission distance between the terminal and all satellites; D s is the transmission distance between the terminal and the satellite s; All resources for satellite s; is the used resources of satellite s; r max is the maximum value of resources among all satellites; T s T is the service time of satellite s to the terminal; max T is the maximum service time of all satellites to the terminal; req The service time required for the terminal; T m It is the minimum of the required service time for the terminal and the maximum service time of all satellites to the terminal.

[0089] S106: Select the target satellite with the largest weight value as the access node, and prepare a backup satellite in the same layer or across layers.

[0090] Furthermore, the weighted value is max s∈S c s The target satellite is determined as the access node. That is, in this embodiment, C is selected from S s The target satellite with the maximum value is selected as the preferred access satellite.

[0091] In an optional implementation, the dynamic setting rule of the weight factor includes:

[0092] If a service is determined to be latency-sensitive based on the terminal's service and QoS requirements, the transmission distance weighting factor is increased. If a service is determined to be resource-intensive based on the terminal's service and QoS requirements, the satellite resource weighting factor is increased. If a service is determined to be a long-connection stable service based on the terminal's service and QoS requirements, the service time weighting factor is increased. In other words, the corresponding weighting factors are dynamically adjusted to meet different user needs based on different service requirements.

[0093] Figure 6 The control plane satellite selection and clustering block diagram is shown. First, obtaining the satellite's broadcast ephemeris or geographic location information from the system is a prerequisite for efficient access. The terminal selects the optimal satellite channel access in real time based on the constellation's operational status, satellite-to-ground connection topology, historical access data, visible satellite link quality assessment and prediction, visible satellite service capabilities, and regional interference status, ensuring robustness and resilience of terminal control plane access in interference environments.

[0094] For services with different QoS requirements, satellite access can be selected based on different rules:

[0095] Delay-sensitive services. Select satellite access with the shortest path and queuing delay to minimize propagation and queuing delays. For example, real-time control services and voice services also require relatively short delays and establish reliable end-to-end connections.

[0096] Services requiring high reliability: Battlefield weapon control and intelligence data require high transmission reliability, with extremely high bit error rates and packet loss rates. Therefore, satellite access with high link quality and minimal interference is required.

[0097] Services requiring high transmission rates: Remote sensing reconnaissance images, videos, and other services require high transmission rates and require satellite access with large bandwidth and high speed.

[0098] In an optional embodiment, the provisioning of same-layer or cross-layer backup satellites includes selecting backup satellites using a same-layer multi-coverage strategy or a multi-layer multi-coverage strategy, enabling rapid handover in strong interference environments through spatial redundancy. Multi-satellite backup selection and access is crucial for reliable transmission of space-based heterogeneous networks in strong interference environments. This same-layer and multi-layer backup achieves spatial redundancy, supports multi-satellite backup and rapid handover under strong interference conditions, and ensures strong terminal connectivity.

[0099] In specific implementation, access strategies and processes are as follows Figure 7 As shown, the details are as follows:

[0100] 1) First, determine the satellite access strategy, namely the same-layer multiple coverage satellite access strategy and the multi-layer multiple coverage satellite access strategy;

[0101] 2) Evaluate the satellite-to-ground link status based on user QoS requirements, satellite-to-ground topology, network load, satellite-to-ground link, satellite resources, and satellite-to-ground electromagnetic environment;

[0102] 3) Select the satellite with the best match between satellite-to-ground link quality, satellite resources, network load and user QoS for access, and prepare multiple satellites as backup for terminal access.

[0103] At the same time, in response to complex electromagnetic environments, we can utilize spatial redundancy, the differences in geometric positions between low orbit and high orbit, and the effects of interference to find satellites with larger bandwidth and stronger anti-interference capabilities.

[0104] Taking into account the above constraints and processes, this embodiment models the satellite selection access optimization strategy as maximizing access probability and user satisfaction under the above constraints. The details are as follows:

[0105] max s∈S C s ;

[0106]

[0107] T max =max{T s},s∈S;

[0108] T m =min(T req ,T max );

[0109]

[0110] D min =min{D s},s∈S;

[0111] The values ​​of α, β, and γ vary depending on the terminal's service and QoS requirements. For broadband and time-sensitive services, α takes the largest value; for services with high resource requirements, β takes a larger value; and for services requiring a stable connection, γ takes a larger value.

[0112] See also Figures 8 and 9In the specific implementation of this embodiment, a multi-layer heterogeneous satellite network space segment is used. Service types include voice services requiring stable connections, data services, and time-sensitive services such as video conferencing. The duration of voice communications follows a negative exponential distribution with a mean of 180 seconds. 10,000 users are randomly distributed around the globe, with even traffic distribution. Satellite resource utilization is randomly set between 20% and 80%. The equivalent satellite runtime in the simulation is 1,000 hours, and the actual computer runtime in the simulation is 50 to 200 minutes (different traffic densities result in different runtimes). Using the above constellation and simulation settings, a simulation comparison is conducted on the access success rate and average handoff count of a multi-layer heterogeneous satellite network and a single-layer LEO constellation under different traffic densities, as well as user satisfaction with different satellite selection access strategies in the multi-layer heterogeneous satellite network under different traffic densities. The simulation results show that, through the multi-layer heterogeneous satellite network architecture and satellite selection access method of the present invention, the access success probability of the multi-layer heterogeneous satellite network is improved by an order of magnitude compared to the single-layer LEO satellite network, and the average number of user handoffs between different satellites is reduced by 60% to 70%.

[0113] In summary, the present invention fully leverages the advantages of GEO satellites, IGSO satellites, polar-orbiting constellations, and Walker constellations to establish a multi-layered, heterogeneous satellite network integrating GEO, IGSO, polar-orbiting, and Walker constellations. This leverages these advantages to provide diverse services to users worldwide. In this multi-layered, heterogeneous satellite network, satellites on each layer have different altitudes and speeds relative to the ground, resulting in varying path loss, latency, and service times. Consequently, the bandwidth, data rate, real-time performance, service duration, and inter-beam / inter-satellite handoff frequency that can be provided to users vary. Therefore, it is necessary to select the most suitable satellite to provide services based on the user's specific service needs and QoS requirements. In this regard, the present invention further studies the multi-layer heterogeneous satellite network architecture and establishment process based on global coverage requirements and diversified business requirements, and establishes a multi-layer heterogeneous satellite network satellite selection and access optimization model for user business and QoS requirements based on the constellation operation status, satellite-ground connection topology, regional interference situation, historical access data, link quality assessment and satellite service capabilities. The satellites are optimized and scheduled and configured through the satellite selection and access optimization algorithm, thereby improving the system access success rate and system robustness while meeting user business requirements and QoS requirements.

[0114] It should be noted that the present invention can be implemented in software and / or a combination of software and hardware, for example, can be implemented using an application specific integrated circuit (ASIC), a general purpose computer or any other similar hardware device. In one embodiment, the software program of the present invention can be executed by a processor to implement the above steps or functions. Similarly, the software program of the present invention (including related data structures) can be stored in a computer-readable recording medium, for example, a RAM memory, a magnetic or optical drive or a floppy disk and similar devices. In addition, some steps or functions of the present invention can be implemented using hardware, for example, as a circuit that cooperates with a processor to perform each step or function.

[0115] The present invention can be implemented as a computer-implemented method on a computer, or in dedicated hardware, or a combination thereof. The executable code for the method according to the present invention, or portions thereof, can be stored on a computer program product. Examples of computer program products include memory devices, optical storage devices, integrated circuits, servers, online software, and the like. Optionally, the computer program product includes non-transitory program code components stored on a computer-readable medium so that when the program product is executed on a computer, the method according to the present invention is executed.

[0116] In an alternative embodiment, the computer program comprises computer program code means adapted to perform all the steps of the method according to the invention when the computer program is run on a computer.Alternatively, the computer program is embodied on a computer readable medium.

[0117] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising 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 device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present invention is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0118] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A multi-layer heterogeneous satellite network architecture, characterized in that: Includes: A GEO satellite layer is composed of a plurality of geostationary orbit satellites, wherein the geostationary orbit satellites are distributed over a preset area according to a preset distribution rule, and inter-satellite links are established between the geostationary orbit satellites; The IGSO satellite layer is composed of multiple inclined geosynchronous orbit satellites with an orbital inclination of 70 degrees, which are evenly distributed in the same orbit and have inter-satellite links established between the inclined geosynchronous orbit satellites; The LEO satellite layer includes a polar-orbiting constellation covering the polar regions and a Walker constellation covering mid- and low-latitudes; the polar-orbiting constellation has 12 orbits, each containing 6 LEO satellites at an orbital altitude of 1250 km; the Walker constellation has 12 orbits, each containing 9 LEO satellites, with an inclination of 55 degrees and an orbital altitude of 1000 km; A microwave inter-satellite link is established between the GEO satellite layer and the LEO satellite layer, and an inter-satellite link is established between the IGSO satellite layer and the LEO satellite layer; and there is no direct inter-satellite link connection between the polar orbit constellation and the Walker constellation.

2. The multi-layer heterogeneous satellite network architecture according to claim 1, characterized in that: The GEO satellite layer is composed of at least 5 geostationary orbit satellites, and 3 of the geostationary orbit satellites are evenly distributed over the equator, and at least two of the geostationary orbit satellites are distributed over the predetermined territory and surrounding areas.

3. A satellite selection and access method based on the multi-layer heterogeneous satellite network architecture according to any one of claims 1 to 2, characterized in that: Including steps: Calculating a connection relationship between each satellite and the terminal according to the terminal position and satellite ephemeris in the multi-layer heterogeneous satellite network architecture, and determining a set of accessible satellites based on the connection relationship; Dynamically set weight factors according to terminal service requirements and QoS requirements; wherein the weight factors include transmission distance weight factor, satellite resource weight factor and service time weight factor; Calculating the real-time positions of satellites in the accessible satellite set, and calculating the transmission distance and service time between each satellite and the terminal based on the satellite ephemeris; Obtaining the used resources of the satellite and the total resource set according to the usage of the resources of each satellite in the accessible satellite set; Calculating a weighted value for each satellite in the accessible satellite set according to the weight factor, the transmission distance, the service time, and satellite resource information; The target satellite with the largest weighted value is selected as the access node, and a same-layer or cross-layer backup satellite is prepared.

4. The satellite access method according to claim 3, characterized in that: The weighted value for each satellite is calculated based on the following formula: T max =max{T s },s∈S; T m =min(T req ,T max ); D min =min{D s },s∈S; Among them, C s is the weighted value of satellite s after considering transmission distance, available resources and service time; S is the set of accessible satellites; α is the transmission distance weight factor; β is the satellite resource weight factor; γ is the service time weight factor; D min The minimum transmission distance between the terminal and all satellites; D s is the transmission distance between the terminal and satellite s; All resources for satellite s; is the used resources of satellite s; R max is the maximum value of resources among all satellites; T s T is the service time of satellite s to the terminal; max T is the maximum service time of all satellites to the terminal; req The service time required for the terminal; T m It is the minimum of the required service time for the terminal and the maximum service time of all satellites to the terminal.

5. The satellite selection and access method according to claim 4, characterized in that: The weighted value is max s∈S C s The target satellite is determined as the access node.

6. The satellite access method according to claim 3, characterized in that: The dynamic setting rules of the weight factor include: If the service is determined to be a delay-sensitive service based on the terminal service requirements and QoS requirements, increasing the transmission distance weight factor; If the service is determined to be a high-resource-demand service based on the terminal service demand and QoS requirements, the satellite resource weight factor is increased; If it is determined to be a long connection stable service based on the terminal service requirements and QoS requirements, the service time weight factor is increased.

7. The satellite access method according to claim 3, characterized in that: Preparing the same-layer or cross-layer backup satellite includes: A same-layer multiple coverage strategy or a multi-layer multiple coverage strategy is used to select backup satellites, and rapid switching in a strong interference environment is achieved through spatial redundancy.

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