Network Capacity Analysis Based On Large LEO Satellite Constellation

Ground networks have disadvantages compared to space networks,such as small scale,scarce resources,and high transmission costs.Space networks are classified into large low Earth orbit(LEO)satellite networks,medium-to-high orbit satellite networks,and geostationary orbit(GEO)satellite networks based on orbital altitude.Large LEO satellite constellations connect remote areas,oceans,and space terminals through inter-satellite links and satellite-to-ground links,providing high-speed internet and local area network communication services.Compared to high orbit satellites,they have lower transmission latency,and compared to traditional GEO satellites,they have higher bandwidth and global coverage,making them an important component of future communication infrastructure.In large LEO satellite constellations,satellite cooperation is required to provide global coverage communication services.This cooperation communication relies on network capacity,making network capacity a key metric for evaluating satellite constellation communication performance.This article aims to address the data transmission problem in large LEO satellite networks to achieve the goal of maximizing network capacity.It introduces the multi-commodity flow problem and its improvements,particularly considering the practical data packet transmission scenario where each packet can only select one path for transmission.Therefore,the article selects the indivisible multi-commodity flow problem that better suits the large LEO satellite network scenario for satellite network capacity calculation.Considering that large LEO satellite constellations are highly dynamic systems,the network needs to change the paths of transmitted traffic over time.However,changing paths interrupts connections and affects service quality.To improve service quality,a dynamic indivisible multi-commodity flow problem is proposed,considering factors such as time steps,traffic variations,and path changes,to optimize satellite network capacity.To reduce the algorithm’s time complexity,a sequential randomized rounding heuristic algorithm is proposed to solve multi-commodity flow-like problems.Next,the article also considers the reliability of inter-satellite links and proposes a link detection mechanism.This mechanism first determines link stability,then updates link status by sending Hello packets,and uses broadcast mechanisms to update global link information.This mechanism effectively detects the stability of satellite links and enhances the reliability and stability of data transmission in satellite communication networks.Finally,the article conducts simulation verification on a large LEO satellite simulation platform developed by the Institute of Software,Chinese Academy of Sciences.The simulation considers the performance of different multi-commodity flow problems under different inter-satellite link bandwidth conditions.The results show that the proposed dynamic indivisible multi-commodity flow problem outperforms other multi-commodity flow problems in calculating satellite network capacity,with an improvement of at least 3%.Additionally,the article applies the link detection mechanism to the dynamic indivisible multi-commodity flow problem,further enhancing the network capacity of satellite systems’transmission.