ISTN network evaluation method based on network capacity and throughput

Abstract

The invention discloses an ISTN network evaluation method based on network capacity and throughput, and relates to the technical field of satellite management. According to the method, based on the unreliable ISL, the influence of ISL interruption or recovery on the network capacity is considered, the corresponding CAP-uISL capacity model is constructed, the method can be suitable for dynamic changes of the ISTN network, the throughput of the ISTN network is effectively calculated, the evaluation index is optimized, and the evaluation accuracy of the ISTN network is further improved. According to the method, flow path expansion and virtual vertex are introduced, the throughput is calculated based on the actual flow path, the problem of throughput overestimation possibly caused by a traditional maximum flow algorithm is solved, the throughput calculation process of the ISTN network is simplified, the accuracy of the throughput is improved, the re-counting problem caused by repeated paths is further solved, and the throughput calculation efficiency is improved. The corresponding routing and flow distribution strategy is adjusted in real time according to the state of the ISTN network, and the reliability of the ISTN network can be effectively evaluated.

Description

Technical Field

[0001] The invention relates to the technical field of satellite management, and in particular to an ISTN network evaluation method based on network capacity and throughput. Background Art

[0002] The Integrated Space and Terrestrial Network (ISTN), consisting of thousands of satellites designed to provide global Internet services, has attracted great attention in recent years. Most of the ISTN networks are configured in Walker configuration, which aims to create a network interconnected by inter-satellite links (ISLs) to ensure low-latency global communications. Therefore, as these ISTN networks continue to develop, capacity and throughput will increasingly become important indicators for evaluating their availability and reliability.

[0003] At present, the upper limit of throughput is taken as network capacity and is used as a linear programming problem. The corresponding network capacity is calculated by solving the maximum value, but this may lead to different network capacities under different routing strategies and the problem of being difficult to accurately quantify. The maximum flow algorithm is used to define throughput, but it cannot solve the problem of source / sink overlap, which leads to incorrect calculation of throughput, and the calculated traffic path is inconsistent with the given traffic path, further reducing the accuracy of throughput, making it impossible to accurately evaluate the availability and reliability of the ISTN network. Summary of the invention

[0004] The object of the present invention is to provide an ISTN network evaluation method based on network capacity and throughput to improve the above technical problems.

[0005] In order to achieve the above-mentioned object of the invention, the embodiment of the present invention provides the following technical solutions:

[0006] An ISTN network evaluation method based on network capacity and throughput includes:

[0007] S1. Obtain relevant data of the ISTN network to be evaluated;

[0008] S2, construct the CAP-uISL capacity model based on the unreliable ISL and related data;

[0009] S3, using the CAP-uISL capacity model to calculate the corresponding network capacity;

[0010] S4, based on the constrained path extension and network capacity, the corresponding throughput is calculated using the THP-CPE algorithm;

[0011] S5. Calculate the network utilization corresponding to the ISTN network to be evaluated based on the network capacity and throughput;

[0012] S6. Based on the ISTN network evaluation standard, the network utilization is processed to obtain the evaluation result of the ISTN network to be evaluated.

[0013] Furthermore, the relevant data include infrastructure data and dynamic data corresponding to the ISTN network to be evaluated; the infrastructure data include the number of satellites, the number of orbital planes, the number of satellites per orbital plane, the phase factor, the orbital inclination, the location of the ground station, and the configuration parameters of the intersatellite link; the dynamic data include the intersatellite link fault recovery time and the fault frequency of the intersatellite link in each orbital cycle.

[0014] Furthermore, based on the unreliable ISL, a CAP-uISL capacity model is constructed, including:

[0015] S2-1, calculating the phase deviation of the ISTN network to be evaluated;

[0016] S2-2, based on the phase deviation, the infrastructure data and the dynamic data, construct the network topology of the ISTN network to be evaluated to obtain a corresponding undirected graph;

[0017] S2-3, calculate the availability corresponding to the unreliable ISL;

[0018] S2-4. Based on the availability and the undirected graph, construct the CAP-uISL capacity model.

[0019] Furthermore, the formula corresponding to the phase deviation is:

[0020]

[0021] Where Δf represents the phase deviation between satellites in adjacent orbital planes, F represents the phase factor, MP represents the number of satellites in each orbital plane, and NP represents the number of orbital planes. When F is 0 and NP-1, the corresponding two constellations have the same configuration; when F is When the phase deviation Δf reaches its maximum value

[0022] Furthermore, the formula corresponding to the CAP-uISL capacity model is:

[0023]

[0024] Where ei and ej represent the i-th intersatellite link and the j-th intersatellite link respectively, and ε represents the total number of intersatellite links. represents the availability of the intersatellite link ei at time t, ∑(·) represents the sum function, gt represents the undirected graph of the ISTN network to be evaluated, C(gt) represents the network capacity corresponding to the unreliable intersatellite link of the ISTN network to be evaluated, xj represents the effective time of the intersatellite link ej, that is, the normal working time of the intersatellite link ej, k represents the intersatellite link index value, E [ · ] represents the expected network capacity C(gt), Ce represents the intersatellite link capacity, i.e., ISL capacity, T represents the orbital period of the ISTN network to be evaluated, σ represents the intersatellite link fault recovery time, and λ represents the fault frequency of the intersatellite link in each orbital period.

[0025] Further, the calculation of the corresponding throughput using the THP-CPE algorithm based on the constrained path extension and the network capacity includes:

[0026] S4-1. Based on the global population mapping and the gross domestic product mapping, a traffic demand matrix corresponding to the ISTN network to be evaluated is generated;

[0027] S4-2, based on the traffic demand matrix, determining the traffic demand between the source satellite and the sink satellite in the ISTN network to be evaluated;

[0028] S4-3, determining a corresponding flow path based on the flow demand and the phase deviation;

[0029] S4-4, generating a corresponding traffic load graph based on the traffic demand and the traffic path;

[0030] S4-5. According to the traffic load diagram, the corresponding throughput is calculated by using the THP-CPE algorithm.

[0031] Further, the calculating the corresponding throughput by THP-CPE algorithm according to the traffic load graph includes:

[0032] S4-5-1. Set up super source nodes and sink nodes;

[0033] S4-5-2, initializing the traffic load graph;

[0034] S4-5-3, initialize the number Ngsl(si) of ground stations connected to each satellite si in the ISTN network to be evaluated;

[0035] S4-5-4, based on the traffic path and the corresponding traffic demand, using a routing algorithm to generate a corresponding actual traffic path;

[0036] S4-5-5, setting two virtual fixed points as the starting point and the target point of the actual flow path, respectively as the source ground station and the target ground station, that is, extending the flow path;

[0037] S4-5-6, calculate the transmission throughput of all traffic paths;

[0038] S4-5-7, based on the transmission throughput and the extended traffic path, updating the traffic load map;

[0039] S4-5-8. Calculate the throughput of each traffic path of the updated traffic load graph and summarize them to obtain the throughput of the ISTN network to be evaluated.

[0040] Furthermore, the network utilization rate corresponds to the following calculation formula:

[0041]

[0042] Among them, T(G) represents the throughput corresponding to the ISTN network G to be evaluated, U(G) represents the network utilization corresponding to the ISTN network G to be evaluated, and C(G) represents the network capacity corresponding to the ISTN network G to be evaluated.

[0043] Furthermore, the ISTN network evaluation criteria are:

[0044] When the network utilization U(G) corresponding to the ISTN network to be evaluated is greater than 75%, the evaluation result of the ISTN network to be evaluated is: the performance corresponding to the ISTN network is excellent;

[0045] When the network utilization U(G) corresponding to the ISTN network to be evaluated is greater than 50% and does not exceed 75%, the evaluation result of the ISTN network to be evaluated is: the performance corresponding to the ISTN network is good;

[0046] When the network utilization U(G) corresponding to the ISTN network to be evaluated does not exceed 50%, the evaluation result of the ISTN network to be evaluated is: the performance corresponding to the ISTN network is low.

[0047] The effective effects of the present invention are:

[0048] The present invention is based on unreliable ISL, considers the impact of ISL interruption or recovery on network capacity, constructs a corresponding CAP-uISL capacity model, can be applied to the dynamic changes of ISTN network, effectively calculates the throughput of ISTN network, optimizes evaluation indicators, and further improves the evaluation accuracy of ISTN network. The present invention introduces traffic path extension and virtual vertices, calculates throughput based on actual traffic path, solves the problem of throughput overestimation that may be caused by traditional maximum flow algorithm, simplifies the throughput calculation process of ISTN network, improves the accuracy of throughput, further solves the problem of re-counting caused by repeated paths, adjusts the corresponding routing and traffic distribution strategies according to the status of ISTN network in real time, and can effectively evaluate the reliability of ISTN network. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0050] Figure 1 is a flow chart of a method in an embodiment of the present invention;

[0051] Figure 2 Schematic diagram of intersatellite link availability in an embodiment of the present invention;

[0052] Figure 3 Schematic diagrams of flow paths and flow paths under different algorithms in the embodiments of the present invention; (a) a schematic diagram of flow paths and flow paths under one algorithm for multi-source multi-sink maximum flow; (b) a schematic diagram of flow paths and flow paths under another algorithm for multi-source multi-sink maximum flow; (c) a schematic diagram of flow paths and flow paths under the ATC-CPE algorithm;

[0053] Figure 4 Schematic diagrams of simulations of different public constellation networking constellations in the embodiments of the present invention; wherein (a) is a schematic diagram of simulation of Kuiper; (b) is a schematic diagram of simulation of OneWeb; (c) is a schematic diagram of simulation of Telesat; (d) is a schematic diagram of simulation of Starlink;

[0054] Figure 5 Schematic diagram of network capacity and remaining capacity of four public constellation networked constellations under different fault frequencies and inter-satellite link fault recovery times in an embodiment of the present invention; wherein (a) is a bar graph of network capacity of four public constellation networked constellations under different fault frequencies; (b) is a curve graph of remaining capacity of four public constellation networked constellations under different inter-satellite link fault recovery times;

[0055] Figure 6 Graphs showing throughput and network utilization of different constellations in an embodiment of the present invention; wherein (a) is a graph showing throughput of different constellations; (b) is a graph showing network utilization of different constellations;

[0056] Figure 7 The throughput and average path utilization curves corresponding to different algorithms in the embodiments of the present invention are shown in FIG. 1 , wherein (a) is a throughput curve diagram corresponding to different algorithms; and (b) is an average path utilization curve diagram corresponding to different algorithms. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and represented in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0058] See also Figure 1 , an ISTN network evaluation method based on network capacity and throughput provided in this embodiment includes:

[0059] S1. Obtain relevant data of the ISTN network to be evaluated;

[0060] The relevant data include infrastructure data and dynamic data corresponding to the ISTN network to be evaluated; the infrastructure data include the number of satellites, the number of orbital planes, the number of satellites per orbital plane, the phase factor, the orbital inclination, the location of the ground station, and the configuration parameters of the intersatellite link; the dynamic data include the intersatellite link fault recovery time and the fault frequency of the intersatellite link in each orbital cycle.

[0061] S2. Based on the unreliable ISL and related data, a CAP-uISL capacity model is constructed; where ISL is an inter-satellite link.

[0062] The network capacity of the ISTN network depends on the data processing rate, the total uplink and downlink capacity. Assuming that the capacity of all ISLs is the same, the formula corresponding to the network capacity C(G) is:

[0063]

[0064] Among them, C(ej) represents, represents, and represents.

[0065] Based on the unreliable ISL, the CAP-uISL capacity model is constructed, including:

[0066] S2-1, calculating the phase deviation of the ISTN network to be evaluated;

[0067] The formula corresponding to the phase deviation is:

[0068]

[0069] Where Δf represents the phase deviation between satellites in adjacent orbital planes, F represents the phase factor, MP represents the number of satellites in each orbital plane, and NP represents the number of orbital planes. When F is 0 and NP-1, the corresponding two constellations have the same configuration; when F is When the phase deviation Δf reaches its maximum value

[0070] S2-2, based on the phase deviation, the infrastructure data and the dynamic data, construct the network topology of the ISTN network to be evaluated to obtain a corresponding undirected graph;

[0071] S2-3, calculate the availability corresponding to the unreliable ISL;

[0072] S2-4. Based on the availability and the undirected graph, construct the CAP-uISL capacity model.

[0073] Due to the high dynamics of the ISTN network, the ISL is not necessarily stable and may have periodic interruptions, which will lead to the network capacity of the ISTN network. Therefore, in order to improve the calculation accuracy of the network capacity of the ISTN network, unreliable ISL is introduced. Assuming that the satellite orbit period is the same, Figure 2 As shown, ISL is in an available time period After the failure, it returns to normal after the intersatellite link failure recovery time σ. The corresponding formula for the availability of the intersatellite link ei at time t is:

[0074]

[0075] When availability When 1, it indicates that the ISL is available; when the availability When it is 0, it means that ISL is unavailable, so the network capacity formula corresponding to the CAP-uISL capacity model is:

[0076]

[0077] Due to the ISL availability period It follows an exponential distribution and is unstable due to orbital motion, i.e., the available time period It is related to the orbital period T. Therefore, in practical applications, ISL has the advantages of larger bandwidth and smaller coherent interference. Assuming that all ISLs have constant capacity, the expected formula corresponding to the CAP-uISL capacity model is:

[0078]

[0079] Where ei and ej represent the i-th intersatellite link and the j-th intersatellite link respectively, and ε represents the total number of intersatellite links. represents the availability of the intersatellite link ei at time t, ∑(·) represents the summation function, gt represents the undirected graph of the ISTN network to be evaluated, C(gt) represents the network capacity corresponding to the unreliable intersatellite link of the ISTN network to be evaluated, xj represents the effective time of the intersatellite link ej, that is, the normal working time of the intersatellite link ej, k represents the intersatellite link index value, E[·] represents the expectation of the network capacity C(gt), Ce represents the intersatellite link capacity, that is, the ISL capacity, T represents the orbital period of the ISTN network to be evaluated, σ represents the fault recovery time of the intersatellite link, and λ represents the fault frequency of the intersatellite link in each orbital period.

[0080] S3, using the CAP-uISL capacity model to calculate the corresponding network capacity;

[0081] S4, based on the constrained path extension and network capacity, the corresponding throughput is calculated using the THP-CPE algorithm;

[0082] The method of calculating the corresponding throughput using the THP-CPE algorithm based on the constrained path extension and the network capacity includes:

[0083] S4-1. Based on the global population mapping and the gross domestic product mapping, a traffic demand matrix corresponding to the ISTN network to be evaluated is generated;

[0084] S4-2, based on the traffic demand matrix, determining the traffic demand between the source satellite and the sink satellite in the ISTN network to be evaluated;

[0085] S4-3, determining a corresponding flow path based on the flow demand and the phase deviation;

[0086] S4-4, based on the traffic demand and the traffic path, generate a corresponding traffic load diagram; the traffic load is obtained based on the traffic demand di and the traffic path pi between the source satellite vs and the sink satellite vt in the ISTN network to be evaluated. The traffic demand is articulated through the traffic demand matrix |v|×|v|, and the corresponding traffic path pi is formulated according to the routing mechanism; based on the traffic demand di and the traffic path pi, the corresponding traffic load is constructed<pi,di> ; All traffic load<pi,di> Synthesize a traffic load graph gf.

[0087] S4-5. According to the traffic load diagram, the corresponding throughput is calculated by using the THP-CPE algorithm.

[0088] The calculating the corresponding throughput by using the THP-CPE algorithm according to the traffic load graph includes:

[0089] S4-5-1. Set up super source nodes and sink nodes;

[0090] S4-5-2, initializing the traffic load graph;

[0091] S4-5-3, initialize the number Ngsl(si) of ground stations connected to each satellite si in the ISTN network to be evaluated;

[0092] S4-5-4, based on the traffic path and the corresponding traffic demand, using a routing algorithm to generate a corresponding actual traffic path;

[0093] S4-5-5, setting two virtual fixed points as the starting point and the target point of the actual flow path, respectively as the source ground station and the target ground station, that is, extending the flow path;

[0094] S4-5-6, calculate the transmission throughput of all traffic paths;

[0095] S4-5-7, based on the transmission throughput and the extended traffic path, updating the traffic load map;

[0096] S4-5-8. Calculate the throughput of each traffic path of the updated traffic load graph and summarize them to obtain the throughput of the ISTN network to be evaluated.

[0097] like Figure 3 As shown in (a) of , the algorithm used may have the problem that if a node is connected to both the super source node and the sink node at the same time, it may get the wrong throughput; Figure 3 As shown in (b), the algorithm used can solve Figure 3 The algorithm used in (a) in the figure corresponds to the problem. However, due to the difference between the traffic path calculated by the algorithm and the actual traffic path, the final traffic value still exceeds the actual throughput of the traffic path; Figure 3 As shown in (c), the THP-CPE algorithm can solve Figure 3 The problem corresponding to the algorithm used in (b) in Figure 1. Some relevant data of the ISTN network in the THP-CPE algorithm are shown in Table 1.

[0098] Table 1

[0099]

[0100]

[0101] Depend on Figure 3 It can be seen that the complexity of the THP-CPE algorithm of the present invention is much smaller than Figure 3 (a) and Figure 3 (b) The corresponding complexity of the traditional algorithm used.

[0102] S5. Calculate the network utilization corresponding to the ISTN network to be evaluated based on the network capacity and throughput;

[0103] The network utilization rate corresponds to the following calculation formula:

[0104]

[0105] Among them, T(G) represents the throughput corresponding to the ISTN network G to be evaluated, U(G) represents the network utilization corresponding to the ISTN network G to be evaluated, and C(G) represents the network capacity corresponding to the ISTN network G to be evaluated. Among them, the throughput of the ISTN network is less than the corresponding network capacity, that is, T(G)<C(G).

[0106] S6. Based on the ISTN network evaluation standard, the network utilization is processed to obtain the evaluation result of the ISTN network to be evaluated.

[0107] The ISTN network evaluation criteria are:

[0108] When the network utilization U(G) corresponding to the ISTN network to be evaluated is greater than 75%, the evaluation result of the ISTN network to be evaluated is: the performance corresponding to the ISTN network is excellent;

[0109] When the network utilization U(G) corresponding to the ISTN network to be evaluated is greater than 50% and does not exceed 75%, the evaluation result of the ISTN network to be evaluated is: the performance corresponding to the ISTN network is good;

[0110] When the network utilization U(G) corresponding to the ISTN network to be evaluated does not exceed 50%, the evaluation result of the ISTN network to be evaluated is: the performance corresponding to the ISTN network is low.

[0111] In one embodiment of the present invention, four public constellation network constellations are used, namely OneWeb, Kuiper, Telesat and Starlink. The ISTN capacity corresponding to the four public constellation network constellations is calculated using the CAP-uISL capacity model; traffic loads are generated and applied to the public constellation network constellations respectively, and the corresponding throughput is calculated using the THP-CPE algorithm.

[0112] like Figure 4 As shown in Figure 2, the simulation scenarios corresponding to Oneweb, Kuiper, Telesat and Starlink are constructed using open source, and the corresponding parameter settings are shown in Table 2.

[0113] Table 2

[0114] Constellation Name Number of orbital planes Number of satellites / orbit Height / km Orbital inclination Kuiper 17 34 630 51.9° OneWeb 12 49 1200 87.9° Telesat 40 33 1325 50.9° Starlink 22 72 550 53°

[0115] Generate the corresponding traffic demand matrix, which describes the traffic demand between the ISTN network and the cities covered by the ground battle. The traffic rate of each traffic demand is scaled from 0 to 10 Gbps and is proportional to the population product in the city. For each simulation, more than 5000 end-to-end loads are generated at each time interval within 24 hours with an interval of 1 hour, and the corresponding parameter settings are shown in Table 3.

[0116] Table 3

[0117]

[0118]

[0119] Adjust the fault frequency λ and the intersatellite link fault recovery time σ, and use the CAP-uISL capacity model to calculate the corresponding network capacity and remaining capacity. Figure 5 As shown in (a) in the figure, when the fault frequency λ is adjusted to 10, the network capacity is reduced to 10% compared with the network capacity of the reliable ISL model; when the fault frequency λ is adjusted to 20, the network capacity is reduced to 20% to 22% compared with the network capacity of the reliable ISL model (failure frequency λ is 0); when the fault frequency λ is adjusted to 40, the network capacity is reduced to 29% to 33% compared with the network capacity of the reliable ISL model. Figure 5 As shown in (b), when the intersatellite link fault recovery time σ is 2 and the fault frequency λ is greater than 10, the network capacity decreases by at least 20%; when the intersatellite link fault recovery time σ is 10, the network capacity decreases by at least 50%. It can be seen that reducing the fault frequency λ and the intersatellite link fault recovery time σ can enable the ISTN network to maintain a higher capacity and thus support more traffic. Figure 5 In the figure, blue indicates that the adjustment failure frequency λ is 40, orange indicates that the adjustment failure frequency λ is 20, green indicates that the adjustment failure frequency λ is 10, and red indicates that the adjustment failure frequency λ is 0.

[0120] The reduction in network capacity will enable the ISTN network to utilize fewer resources, thereby reducing throughput and leading to reduced utilization. The CAP-uISL capacity model is used to explore the variation of throughput with network load (traffic load) under different ISTN networks. At least 5000 traffic loads are generated using a random traffic matrix and the shortest distance path algorithm (SDP algorithm), and the THP-CPE algorithm is used to calculate the throughput changes corresponding to the four public constellations.

[0121] like Figure 6 As shown in (a) in the figure, when the network load exceeds 10 3 When the network load exceeds 2×10 3 When the network load exceeds 3×10 3 When , Starlink's corresponding throughput reaches 13.43Tbps. Figure 6 As shown in (b), when the maximum throughput is reached, the network utilization of all constellations is 46.32%. This is because the same constellation uses the SDP algorithm without any congestion control mechanism. Different ISL reliabilities will affect the network throughput. When the fault frequency λ is adjusted to 40, the throughput of Starlink is only 9.65Tbps, which is 28% lower than the throughput of Starlink when the fault frequency λ is adjusted to 0, which is 13.43Tbps. When the fault frequency λ is adjusted to 40, the throughput of Kuiper is only 4.02Tbps, which is 22% lower than the throughput of Kuiper when the fault frequency λ is adjusted to 0. It can be seen that improving ISL reliability is also an important way to improve the throughput of the ISTN network. The larger the network capacity of the ISTN network, the greater the impact of ISL reliability on throughput. The throughput of Oneweb and Kuiper reaches saturation when it exceeds 1,000 traffic loads, the throughput of Telesat reaches saturation when it exceeds 2,000 traffic loads, and the throughput of Starlink reaches saturation when it exceeds 4,000 traffic loads. Since traffic loads rarely occupy the full capacity of an ISL and become blocking flows, the number of loads in actual application environments will be much larger.

[0122] The Dinic algorithm, the combined algorithm of Dinic+SP and the THP-CPE algorithm of the present invention are used for comparison. Figure 7As shown in (a) and (b), when the Dinic algorithm calculates the flow path, there are nodes connected to the super source node and the aggregation node at the same time, which means that two ground stations transmit data through a satellite without using ISL forwarding, that is, bent pipe forwarding. The corresponding actual utilization rate will be larger and is related to the capacity value of the super star link; in the Dinic+SP algorithm, although the problem of error shortcuts is solved, due to the difference between the calculated flow path and the traffic path, there will still be a large value, so the corresponding error is greater than 1. In the THP-CPE algorithm of the present invention, the error shortcuts are overcome, and the throughput calculated in the maximum case is allowed to be less than the maximum traffic value, but the generation of the flow path is allowed to follow the evolution of the traffic path, which makes the throughput calculation less than the maximum traffic value in the optimal case, but closer to the actual value under the current traffic load, and the utilization rates are all less than 100%. Figure 7 In the figure, red represents the Dinic algorithm, green represents the Dinic+SP combined algorithm, and blue represents the THP-CPE algorithm of the present invention. The formula corresponding to the average path utilization U(p) is:

[0123]

[0124] In summary, the present invention is based on unreliable ISL, considers the impact of ISL interruption or recovery on network capacity, constructs a corresponding CAP-uISL capacity model, which can be applied to the dynamic changes of ISTN network, effectively calculates the throughput of ISTN network, optimizes evaluation indicators, and further improves the evaluation accuracy of ISTN network. The present invention introduces traffic path extension and virtual vertices, calculates throughput based on actual traffic path, solves the problem of throughput overestimation that may be caused by traditional maximum flow algorithm, simplifies and ISTN network throughput calculation process, improves the accuracy of throughput, further solves the problem of re-counting caused by repeated paths, and adjusts the corresponding routing and traffic distribution strategy according to the state of ISTN network in real time, which can effectively evaluate the reliability of ISTN network. The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An ISTN network evaluation method based on network capacity and throughput, characterized in that: include: S1. Obtain relevant data of the ISTN network to be evaluated; S2, construct the CAP-uISL capacity model based on the unreliable ISL and related data; S3, using the CAP-uISL capacity model to calculate the corresponding network capacity; S4, based on the constrained path extension and network capacity, the corresponding throughput is calculated using the THP-CPE algorithm; S5. Calculate the network utilization corresponding to the ISTN network to be evaluated based on the network capacity and throughput; S6. Based on the ISTN network evaluation standard, the network utilization is processed to obtain the evaluation result of the ISTN network to be evaluated.

2. According to the ISTN network evaluation method based on network capacity and throughput according to claim 1, it is characterized in that: The relevant data include infrastructure data and dynamic data corresponding to the ISTN network to be evaluated; the infrastructure data include the number of satellites, the number of orbital planes, the number of satellites per orbital plane, the phase factor, the orbital inclination, the location of the ground station, and the configuration parameters of the intersatellite link; the dynamic data include the intersatellite link fault recovery time and the fault frequency of the intersatellite link in each orbital cycle.

3. According to the ISTN network evaluation method based on network capacity and throughput according to claim 2, it is characterized in that: Based on the unreliable ISL, the CAP-uISL capacity model is constructed, including: S2-1, calculating the phase deviation of the ISTN network to be evaluated; S2-2, based on the phase deviation, the infrastructure data and the dynamic data, construct the network topology of the ISTN network to be evaluated to obtain a corresponding undirected graph; S2-3, calculate the availability corresponding to the unreliable ISL; S2-4. Based on the availability and the undirected graph, construct the CAP-uISL capacity model.

4. According to the ISTN network evaluation method based on network capacity and throughput according to claim 3, it is characterized in that: The formula corresponding to the phase deviation is: Where Δf represents the phase deviation between satellites in adjacent orbital planes, F represents the phase factor, MP represents the number of satellites in each orbital plane, and NP represents the number of orbital planes. When F is 0 and NP-1, the corresponding two constellations have the same configuration; when F is When the phase deviation Δf reaches its maximum value 5. According to the ISTN network evaluation method based on network capacity and throughput according to claim 3, it is characterized in that: The formula corresponding to the CAP-uISL capacity model is: Where ei and ej represent the i-th intersatellite link and the j-th intersatellite link respectively, ε represents the total number of intersatellite links, Yei(t) represents the availability of the intersatellite link ei at time t, ∑(·) represents the summation function, gt represents the undirected graph of the ISTN network to be evaluated, C(gt) represents the network capacity corresponding to the unreliable intersatellite link of the ISTN network to be evaluated, xj represents the effective time of the intersatellite link ej, that is, the normal working time of the intersatellite link ej, k represents the intersatellite link index value, E [ · ] represents the expected network capacity C(gt), Ce represents the intersatellite link capacity, i.e., ISL capacity, T represents the orbital period of the ISTN network to be evaluated, σ represents the intersatellite link fault recovery time, and λ represents the fault frequency of the intersatellite link in each orbital period.

6. According to the ISTN network evaluation method based on network capacity and throughput according to claim 4, it is characterized in that: The method of calculating the corresponding throughput using the THP-CPE algorithm based on the constrained path extension and the network capacity includes: S4-1. Based on the global population mapping and the gross domestic product mapping, a traffic demand matrix corresponding to the ISTN network to be evaluated is generated; S4-2, based on the traffic demand matrix, determining the traffic demand between the source satellite and the sink satellite in the ISTN network to be evaluated; S4-3, determining a corresponding flow path based on the flow demand and the phase deviation; S4-4, generating a corresponding traffic load graph based on the traffic demand and the traffic path; S4-5. According to the traffic load diagram, the corresponding throughput is calculated by using the THP-CPE algorithm.

7. According to the ISTN network evaluation method based on network capacity and throughput according to claim 6, it is characterized in that: The calculating the corresponding throughput by using the THP-CPE algorithm according to the traffic load graph includes: S4-5-1. Set up super source nodes and sink nodes; S4-5-2, initializing the traffic load graph; S4-5-3, initialize the number Ngsl(si) of ground stations connected to each satellite si in the ISTN network to be evaluated; S4-5-4, based on the traffic path and the corresponding traffic demand, using a routing algorithm to generate a corresponding actual traffic path; S4-5-5, setting two virtual fixed points as the starting point and the target point of the actual flow path, respectively as the source ground station and the target ground station, that is, extending the flow path; S4-5-6, calculate the transmission throughput of all traffic paths; S4-5-7, based on the transmission throughput and the extended traffic path, updating the traffic load map; S4-5-8. Calculate the throughput of each traffic path of the updated traffic load diagram and summarize them to obtain the throughput of the ISTN network to be evaluated.

8. The ISTN network evaluation method based on network capacity and throughput according to claim 1, characterized in that: The network utilization rate corresponds to the following calculation formula: Among them, T(G) represents the throughput corresponding to the ISTN network G to be evaluated, U(G) represents the network utilization corresponding to the ISTN network G to be evaluated, and C(G) represents the network capacity corresponding to the ISTN network G to be evaluated.

9. The ISTN network evaluation method based on network capacity and throughput according to claim 8, characterized in that: The ISTN network evaluation criteria are: When the network utilization U(G) corresponding to the ISTN network to be evaluated is greater than 75%, the evaluation result of the ISTN network to be evaluated is: the performance corresponding to the ISTN network is excellent; When the network utilization U(G) corresponding to the ISTN network to be evaluated is greater than 50% and does not exceed 75%, the evaluation result of the ISTN network to be evaluated is: the performance corresponding to the ISTN network is good; When the network utilization U(G) corresponding to the ISTN network to be evaluated does not exceed 50%, the evaluation result of the ISTN network to be evaluated is: the performance corresponding to the ISTN network is low.

Images