Satellite internet digital twin system

Abstract

The invention provides a satellite internet digital twin system, which adopts a micro-service architecture and comprises a physical layer module, a topology module, a path calculation module and a visual interface module, NS-3 is used for packet-level simulation, and the modules communicate with one another through an API (Application Program Interface); the physical layer module is used for simulating a satellite-ground link channel and comprises a beam gain calculation module, a beam interference calculation module and a channel capacity calculation module; the topology module is used for updating a dynamic network topology in real time according to the positions of a satellite and a ground station; the path calculation module is used for performing real-time path analysis according to network topology; and the visual interface module is used for inputting simulation parameters and outputting simulation results. The satellite internet digital twin system can realize satellite network end-to-end simulation, is designed based on a modularized micro-service architecture, and is high in system flexibility and maintainability.

Description

Technical Field

[0001] The present invention relates to the field of satellite Internet communication technology, and in particular, to a satellite Internet digital twin system. Background Art

[0002] The Integrated Space-air-ground Network (SAGIN) enables communications between satellites, aircraft, and ground infrastructure, which is crucial to promoting the deployment of satellite Internet communication technology and achieving global interconnection. It is a revolutionary change in communication technology. The development of this network technology requires advanced simulation tools that can handle complex and dynamic network topologies and deeply analyze network performance.

[0003] In the prior art, satellite Internet simulators, such as Hypatia and STK, use virtual nodes to simulate satellite communication processes, which can reflect the theoretical model of satellite networks to a certain extent. Network simulators, such as Mininet and StarryNet, use physical machines or virtual machines to simulate network deployment operations, which are closer to the actual situation of the network. However, although the existing technologies or patents have solved the problems existing in the simulation of the integrated network of space, land and air in a certain aspect, they are insufficient in realizing the end-to-end simulation of satellite Internet, that is, they fail to simulate the details of all layers in the network protocol stack, and cannot more realistically reproduce and analyze the network characteristics of satellite Internet. Including the channel interference simulation of the physical layer, the fusion simulation of the physical layer and the MAC layer, the packet level simulation, and the flow level analysis of the integrated AI function, it is difficult to fully reflect the complex satellite communication system. In addition, due to the complexity of the integrated network technology of space, land and air, the simulation platform should have a modular design to facilitate the integration or replacement of related technologies at each layer, and support custom network parameters, adding various types of communication equipment, scripted deployment, etc. Therefore, a more flexible satellite Internet digital twin system that can realize end-to-end full-scale simulation is needed. Summary of the invention

[0004] In view of the defects in the prior art, the purpose of the present invention is to provide a satellite Internet digital twin system. The system of the present invention can realize end-to-end simulation of satellite networks, is designed based on a modular microservice architecture, and has strong system flexibility and high maintainability.

[0005] To solve the above problems, the technical solution of the present invention is:

[0006] A satellite Internet digital twin system adopts a microservice architecture, including a physical layer module, a topology module, a path calculation module and a visualization interface module. NS-3 is used for packet level simulation, and each module communicates through an API interface. The physical layer module is used to simulate a satellite-to-ground link channel, including a beam gain calculation module, a beam interference calculation module, and a channel capacity calculation module. The topology module is used to update the dynamic network topology in real time according to the positions of the satellite and the ground station. The path calculation module is used to perform real-time path analysis according to the network topology. The visualization interface module is used to input simulation parameters and output simulation results.

[0007] Preferably, the beam gain calculation module is calculated according to the relative position of the transmitter and the receiver and the direction of the visual axis, and the calculation formula is:

[0008]

[0009] Among them, G max represents the peak antenna gain, J 1 (x) is the first kind and order Bessel function, a represents the antenna aperture radius, represents beam, where f and c represent frequency and speed of light respectively, and θ represents the angle measured from the main beam boresight of the antenna according to the locations of the transmitter and receiver.

[0010] Preferably, the beam interference module calculates the interference level between beams of the same frequency, and the calculation formula is:

[0011]

[0012] Where P I represents the interference power, that is, the sum of the powers of all beams in the interference set, S represents the set of transmitters to which the co-frequency interference beam belongs, and P k represents the beam transmission power, h k,j represents the channel coefficient between the kth transmitter and the jth receiver, G t (θ k,j ) represents the gain of the transmitting antenna of the kth transmitter pointing to the jth receiver, represents the gain of the jth receiver, d k,j represents the spatial distance between the kth transmitter and the jth receiver, and λ represents the signal wavelength.

[0013] Preferably, the channel capacity calculation module calculates the maximum transmission capacity of the link based on the Shannon formula, combining the signal-to-interference-plus-noise ratio, the channel bandwidth, and the environmental noise level, and the calculation formula is:

[0014]

[0015] in represents the channel capacity of transmitter i and receiver j at time t, in bits per second, B represents the signal bandwidth, in Hertz, SINR represents the signal interference plus noise ratio of transmitter i and receiver j at time t, determined using the calculated beam gain and interference level, Pi|h i,j | represents the signal receiving power, where P i is the transmitter power, h i,j is the channel coefficient, k B T rx B represents the theoretical noise power of the receiver, k B is the Boltzmann parameter, T rx is the noise temperature of the receiver, B is the signal bandwidth, ∑ l∈S P l |h l,j |Represents the cumulative interference power of the same-frequency beam.

[0016] Preferably, the beam gain calculation module calculates the beam gain of the antenna and transmits it to the beam interference module and the channel capacity calculation module. The beam interference calculation module determines the interference power level between overlapping beams and transmits it to the channel capacity calculation module. The channel capacity calculation module calculates the channel capacity value based on the beam gain value and the beam interference power. The calculated channel capacity value is input into NS-3 for dynamic simulation. NS-3 adjusts the transmission rate according to the channel capacity of the satellite-to-ground link in different time slots.

[0017] Preferably, the NS-3 communicates with other modules through an API interface, and is used to input physical layer channel quality parameters and path calculation results into the NS-3 simulator for packet level simulation.

[0018] Preferably, the topology module dynamically generates the network topology based on the relative positions of the satellites in the network, and hands it over to the path calculation module to calculate the paths between ground stations or between satellites. When the satellite position and the ground station status change, the path calculation module calculates and generates the path forwarding table in real time to ensure that the data can always select the most effective path according to demand.

[0019] Preferably, the path calculation module takes into account changes in satellite position and the ground network environment, provides real-time feedback on the most efficient path between nodes, and simulates real network behavior, including the impact of satellite movement on the communication layer, and optimal path selection for data transmission.

[0020] Preferably, the visualization interface module is used to visualize simulation results, converting complex network dynamic changes and routing into a 3D visual model, making it easier for users to understand and analyze network behavior, and also helping to discover potential bottlenecks in the network and optimize network configuration.

[0021] Preferably, the real device nodes are connected to the simulation network using the TapBridge interface.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The system of the present invention uses different modules to simulate various levels in the network protocol stack. Each module is a microservice. The microservices communicate through APIs, which improves the efficiency of communication between modules. In addition, the system is designed based on a modular microservice architecture, and has strong system flexibility and high maintainability.

[0024] 2. The core part of the system of the present invention includes a physical layer module, a topology module and a path calculation module, and uses NS-3 to implement packet-level simulation, and uses TapBridge to integrate IP-supported devices in the physical world into a simulated network environment, seamlessly integrating real-world devices.

[0025] 3. The system of the present invention also designs a visual interface module to simplify network simulation operations and intuitively display simulation effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0027] Figure 1 This is a schematic diagram of the satellite internet digital twin system architecture of the present invention;

[0028] Figure 2 A schematic diagram of the interaction relationship between physical layer modules of the satellite internet digital twin system of the present invention;

[0029] Figure 3 This is an example diagram of a system end-to-end simulation effectiveness test according to a specific embodiment of the present invention;

[0030] Figure 4 This is an example diagram of the TCP sending rate of a system under stable channel conditions according to a specific embodiment of the present invention;

[0031] Figure 5 This is an example diagram of the TCP sending rate of a system under fast-changing channel conditions according to a specific embodiment of the present invention;

[0032] Figure 6 This is a comparative example diagram of link status operability between a specific embodiment of the present invention and the simulation platform Hypatia;

[0033] Figure 7 This is an example diagram of a system front-end interface of a specific embodiment of the present invention;

[0034] Figure 8This is a diagram of an end-to-end test instance of a real device according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0036] Specifically, the present disclosure proposes a satellite Internet digital twin system suitable for an integrated space-ground network, which aims to achieve end-to-end simulation of satellite networks and provide flexible architecture and network functions. Figure 1 As shown, the satellite Internet digital twin system includes four components: physical layer module, topology module, path calculation module and visualization interface module, and each module communicates through an API interface. The system of the present invention adopts a microservice architecture, uses NS-3 for package level simulation, uses the TapBridge interface to integrate real devices, uses a visualization module to input simulation parameters, and outputs simulation results.

[0037] Figure 1 The left Input refers to the input parameters related to the network to be simulated, including satellite trajectory, ground station distribution, topology information, coordinates of other devices, etc. The NS-3 module on the right communicates with other modules through interfaces to obtain link information to create a network environment. The front-end module is used to display the network status and provide a convenient user graphical interface for users to adjust simulation parameters and view simulation results.

[0038] For satellite communications, especially low earth orbit satellite communications, the link status between satellite and ground will change rapidly. The simulation component of the physical layer can calculate the channel quality of all satellite-to-ground links at different times based on satellite position, antenna information, noise level, etc. The physical layer module is used to simulate the satellite-to-ground link channel, including three sub-modules: beam gain simulation, beam interference simulation and channel capacity calculation. Each sub-module cooperates to solve the satellite-to-ground link resource analysis.

[0039] 1. Beam gain calculation module

[0040] Based on the antenna position, satellite direction and antenna pattern, the gain of the antenna beam is calculated, taking into account the satellite position and the specific case of the antenna used.

[0041] The calculation formula of this submodule is as follows:

[0042]

[0043] Among them, Gmax represents the peak antenna gain, J 1 (x) is the first-order Bessel function of the first kind, a represents the antenna aperture radius, represents beam, where f and c represent frequency and speed of light respectively, and θ represents the angle measured from the main beam boresight of the antenna according to the locations of the transmitter and receiver.

[0044] 2. Beam interference calculation module

[0045] Beam interference is a phenomenon caused by the superposition of multiple co-frequency beams. The main function of this module is to calculate the interference power between beams sharing the same channel. The calculation process takes into account the antenna gain pattern, the physical spacing between beams, and the direction and position of the satellite to ensure high-fidelity interference values. The relevant calculation formula for beam interference is as follows:

[0046]

[0047] Where P I represents the interference power, that is, the sum of the powers of all beams in the interference set, S represents the set of transmitters to which the co-frequency interference beam belongs, and P k represents the beam transmission power, h k,j represents the channel coefficient between the kth transmitter and the jth receiver, G t (θ k,j ) represents the gain of the transmitting antenna of the kth transmitter pointing to the jth receiver, represents the gain of the jth receiver, d k,j represents the spatial distance between the kth transmitter and the jth receiver, and λ represents the signal wavelength.

[0048] 3. Channel capacity calculation module

[0049] Calculates the maximum available data rate on a satellite link, representing the uplink data throughput limit when the link does not experience transmission errors. The algorithm is based on Shannon's formula, combining the signal-to-interference-plus-noise ratio, channel bandwidth, and ambient noise level.

[0050]

[0051]

[0052] in represents the channel capacity of transmitter i and receiver j at time t, in bits per second, B represents the signal bandwidth, in Hertz, SINR represents the signal interference plus noise ratio of transmitter i and receiver j at time t, determined using the calculated beam gain and interference level, Pi|h i,j | represents the signal receiving power, where P iis the transmitter power, h i,j is the channel coefficient, k B T rx B represents the theoretical noise power of the receiver, k B is the Boltzmann parameter, T rx is the noise temperature of the receiver, B is the signal bandwidth, ∑ l∈S P l |h l,j |Represents the cumulative interference power of the same-frequency beam.

[0053] The relationship between the modules of the physical layer module and the interaction between them and the NS-3 simulation interface are as follows: Figure 2 As shown, the beam gain calculation module calculates the beam gain of the antenna and transmits it to the beam interference module and the channel capacity calculation module. The beam interference calculation module determines the interference power level between overlapping beams and transmits it to the channel capacity calculation module. The channel capacity calculation module calculates the channel capacity value based on the beam gain value and the beam interference power. The calculated channel capacity is about each satellite-to-ground link in the simulation scenario. This information is input into NS-3 for dynamic simulation. NS-3 adjusts the transmission rate according to the channel capacity of the satellite-to-ground link in different time slots.

[0054] The topology module is used to generate and update the network topology in real time according to the positions of satellites and ground stations, and the path calculation module is used to perform real-time path analysis according to the network topology.

[0055] The topology module dynamically generates the network topology based on the relative positions of the satellites in the network, and hands it over to the path calculation module to calculate the paths between ground stations or between satellites. When the satellite position and ground station status change, the path calculation module calculates and generates the path forwarding table in real time to ensure that the data can always choose the most effective path according to demand. Network path calculation is not static, it needs to be updated in real time to reflect the movement and changes of satellites to achieve a simulation that is closer to the real situation, which is more valuable for planning and analyzing satellite routes and paths. The path calculation component can be customized to implement path calculation for different needs, such as fault recovery path calculation, or use designed APIs to connect to existing SDN controllers.

[0056] The path calculation module and the topology module work together to model and analyze network paths. After the topology module generates the network topology, the path calculation module generates detailed path analysis data, which includes theoretical RTT calculation results, routing paths between nodes, and other key network performance indicators. The path calculation module takes into account the changes in satellite positions and the ground network environment, provides real-time feedback on the most effective paths between nodes, and simulates real network behavior, including the impact of satellite movement on the communication layer and the optimal path selection for data transmission. By combining the topology module and the path calculation module, a comprehensive solution for modeling and analyzing complex dynamic converged satellite networks is provided. This approach not only helps understand the performance characteristics of the network, but also helps develop and evaluate new network protocols and configurations to solve the unique problems faced by satellite-ground converged networks.

[0057] The visualization interface module is used to intuitively present the calculation results and convert the complex network dynamic changes and routing into a 3D visualization model. Figure 7 As shown in the figure, the visualization interface module is used to visualize the simulation results, converting complex network dynamic changes and routing into a 3D visual model, making it easier for users to understand and analyze network behavior, and can also help discover potential network bottlenecks and optimize network configuration. By providing a clear and intuitive network perspective, this module greatly enhances the role of network planning and development.

[0058] As a digital twin system, the system of the present invention is different from other simulation platforms in its support for real-world integration. By using NS-3 as the backend, a virtual network environment is created that approximates the real-world network and exposes the simulation topology to the real-world devices. Any device that supports the IP layer can be used to replace the satellite or ground station node to ensure more accurate reflection of network behavior and interaction, connecting the real-world devices to the simulation platform as part of the platform for real-time packet processing.

[0059] The path and network topology can be dynamically updated based on changes in satellite position and ground network configuration, and the path and network parameters can be determined as the satellite moves. This dynamic update process occurs in real time, ensuring that the simulation can reflect the current state of the network in real time. This feature allows the simulation of packet forwarding to take into account factors such as propagation delay and link bandwidth, providing a perspective on network performance and highlighting the platform's ability to effectively simulate complex integrated satellite-ground networks. In addition, the system allows for interactive network topology adjustments in real time and through the UI during simulation.

[0060] In order to further verify the solution of the present invention, experimental tests and test results are described below.

[0061] For the experimental environment, we used the NS-33.31 version, which supports Tap-Bridge, deployed it in Ubuntu 22.04 LTS, and used Linux container (LXC) to instantiate some ground station nodes for experiments. We conducted the following three sets of experiments, using connectivity tests (ping) to prove the effectiveness of the platform. Figure 3 In the given test environment, the Ping operation is used to complete the end-to-end reachability test from the sender on the left to the receiver on the right. The middle part shows the satellite network topology diagram used.

[0062] (1) Physical layer simulation effect test

[0063] This experiment is designed to test the impact of changes in physical layer channel capacity on TCP sending rate. Channel transmission capacity refers to the maximum transmission rate that can be achieved through error-free transmission over a wireless channel.

[0064] The experiment was conducted under two conditions: a stable channel capacity and a rapidly changing channel capacity. Each time an end-to-end communication simulation was performed, the TCP sending rate was recorded and analyzed. Kuiper was used as the experimental simulation scenario. Kuiper is a 34*34 constellation with an altitude of 630km. The experiment only used ground stations for relay transmission. End-to-end communication was performed at the ground station between Pairs and Moscow. The simulation time slot was set to 1s, and the total simulation time was 200s. The channel capacity was set to 10Mbps stable, and dynamically set to 1M to 10M as a rapidly changing channel.

[0065] like Figure 4 , Figure 5 As shown, Figure 4 The TCP sending rate of the simulated terminal in a stable channel environment is shown. When the channel is a stable channel, the sending rate of the upper layer protocol TCP protocol remains almost constant. Figure 5 The simulation terminal's TCP sending rate is shown in a rapidly changing channel environment. When the channel changes rapidly, the TCP sending rate will also change rapidly. This proves that the change of the channel capacity of the physical layer can actually affect the TCP sending rate inside, thus verifying the ability of the simulation system to integrate the protocol stacks of various network layers.

[0066] (2) Custom topology and path calculation algorithm testing

[0067] This experiment is used to verify that the system can support the customization of the intersatellite link status. The Starlink constellation is used, which includes 72 orbital planes, 22 satellites in each orbit, and the satellite orbit is 550km high and has an inclination of 53 degrees.

[0068] For another satellite simulation system Hypatia, it does not support the setting of link failure between nodes or satellites, while all inter-satellite links of the system of the present invention are operational. In this experiment, 10% of the inter-satellite links are set as failed links, the simulation time slice is set to 100ms, and the total simulation time is set to 200s.

[0069] Figure 6 The results of the inter-terminal RTT test with another satellite Internet simulation platform Hypatia were demonstrated, in which the inter-satellite link failure rate was set to 10%, while Hypatia did not provide a defined link function. The performance difference between the two confirmed the effectiveness of link state operations. The system of the present invention can more realistically reflect the dynamics of the link. By adding a 10% inter-satellite link failure rate, the data forwarding capability under non-optimal paths was tested. At the same time, Hypatia cannot set the link failure rate, so all path calculation algorithms are based on the shortest route and show a lower RTT. This experiment proves that the system can support custom link features and that the system can support flexible path calculation methods.

[0070] (3) Real-world integration effect testing

[0071] This experiment aims to prove that the system supports the integration of real-world devices. Starlink is still used as a simulated constellation. The ground stations are located in Shanghai and São Paulo respectively. Two Linux containers are used to represent the two nodes respectively.

[0072] Figure 8 The RTT calculation results of the simulation using Shanghai and Sao Paulo as nodes are shown, where the green curve represents the theoretical result calculated based on the propagation delay, and the orange represents the actual result obtained by end-to-end simulation. The theoretical result is relatively smooth and the RTT is small, while the actual result has jitter and the RTT is large, proving that the system uses the network protocol processing operations in the real node, thereby obtaining RTT data that is closer to the actual situation.

[0073] (4) Visual interface display

[0074] Figure 7 The front-end interface is displayed. The left column shows that the system supports end-to-end simulation between any ground station nodes, and also includes simulation results such as RTT and number of hops. The right option column supports the selection of different communication modes, such as Ping tests at different times.

[0075] The above test results show that it is possible to effectively simulate dynamic satellite networks using real equipment and adapt to various communication models and test algorithms. It is scalable, real-time, and flexible, and is of great value for the development and analysis of space-ground integrated networks.

[0076] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A satellite Internet digital twin system, characterized in that: The system adopts a microservice architecture, including a physical layer module, a topology module, a path calculation module and a visual interface module. NS-3 is used for packet-level simulation, and each module communicates through an API interface. The physical layer module is used to simulate the satellite-to-ground link channel, including a beam gain calculation module, a beam interference calculation module, and a channel capacity calculation module. The topology module is used to update the dynamic network topology in real time according to the location of the satellite and the ground station. The path calculation module is used to perform real-time path analysis according to the network topology; the visual interface module is used to input simulation parameters and output simulation results.

2. The satellite internet digital twin system according to claim 1, characterized in that: The beam gain calculation module is based on the relative position of the transmitter and the receiver and the direction of the visual axis, and its calculation formula is: Among them, G max represents the peak antenna gain, J1(x) is the first-order Bessel function, a represents the antenna aperture radius, represents beam, where f and c represent frequency and speed of light respectively, and θ represents the angle measured from the main beam boresight of the antenna according to the locations of the transmitter and receiver.

3. The satellite internet digital twin system according to claim 1, characterized in that: The beam interference module calculates the interference level between beams of the same frequency, and the calculation formula is: Where P I represents the interference power, that is, the sum of the powers of all beams in the interference set, S represents the set of transmitters to which the co-frequency interference beam belongs, and P k represents the beam transmission power, h k，j represents the channel coefficient between the kth transmitter and the jth receiver, G t (θ k，j ) represents the gain of the transmitting antenna of the kth transmitter pointing to the jth receiver, represents the gain of the jth receiver, d k，j represents the spatial distance between the kth transmitter and the jth receiver, and λ represents the signal wavelength.

4. The satellite internet digital twin system according to claim 1, characterized in that: The channel capacity calculation module calculates the maximum transmission capacity of the link based on the Shannon formula, combining the signal interference plus noise ratio, channel bandwidth, and environmental noise level. The calculation formula is: in represents the channel capacity of transmitter i and receiver j at time t, in bits per second, B represents the signal bandwidth, in Hertz, SINR represents the signal interference plus noise ratio of transmitter i and receiver i at time t, determined using the calculated beam gain and interference level, Pi|h i，j | represents the signal receiving power, where P i is the transmitter power, h i，j is the channel coefficient, k B T rx B represents the theoretical noise power of the receiver, k B is the Boltzmann parameter, T rx is the noise temperature of the receiver, B is the signal bandwidth, ∑ l∈S P l |h l，j |Represents the cumulative interference power of the same-frequency beam.

5. The satellite internet digital twin system according to claim 1, characterized in that: The beam gain calculation module calculates the beam gain of the antenna and transmits it to the beam interference module and the channel capacity calculation module. The beam interference calculation module determines the interference power level between overlapping beams and transmits it to the channel capacity calculation module. The channel capacity calculation module calculates the channel capacity value based on the beam gain value and the beam interference power. The calculated channel capacity value is input into NS-3 for dynamic simulation. NS-3 adjusts the transmission rate according to the channel capacity of the satellite-to-ground link in different time slots.

6. The satellite internet digital twin system according to claim 5, characterized in that: The NS-3 communicates with other modules through an API interface, and is used to input physical layer channel quality parameters and path calculation results into the NS-3 simulator for packet level simulation.

7. The satellite internet digital twin system according to claim 1, characterized in that: The topology module dynamically generates the network topology based on the relative positions of satellites in the network, and sends it to the path calculation module to calculate the paths between ground stations or between satellites. When the satellite position and the ground station status change, the path calculation module calculates and generates the path forwarding table in real time to ensure that the data can always choose the most effective path according to demand.

8. The satellite internet digital twin system according to claim 1, characterized in that: The path calculation module takes into account changes in satellite position and the ground network environment, provides real-time feedback on the most efficient path between nodes, and simulates real network behavior, including the impact of satellite movement on the communication layer, and the optimal path selection for data transmission.

9. The satellite internet digital twin system according to claim 1, characterized in that: The visualization interface module is used to visualize simulation results and convert complex network dynamic changes and routes into 3D visual models, making it easier for users to understand and analyze network behaviors. It can also help discover potential bottlenecks in the network and optimize network configuration.

10. The satellite internet digital twin system according to claim 1, characterized in that: Use the TapBridge interface to connect real device nodes to the simulated network.

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