Shortest Path in LEO Satellite Constellation Networks: An Explicit Analytic Approach

• Published in: IEEE journal on selected areas in communications Vol. 42; no. 5; pp. 1175 - 1187
• Main Authors: Chen, Quan, Yang, Lei, Zhao, Yong, Wang, Yi, Zhou, Haibo, Chen, Xiaoqian
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Communication networks; Computational efficiency; Dijkstra's algorithm; explicit analytic algorithm; Heuristic algorithms; Intersatellite communications; Iterative algorithms; LEO satellite networks; Low earth orbit satellites; Low earth orbits; mega-constellation network; Monte Carlo simulation; Network topology; Orbital mechanics; Orbits; Routing; Satellite communications; Satellite constellations; Satellite networks; Satellites; Shortest path; Shortest-path problems; starlink; Topology
• ISSN: 0733-8716; 1558-0008; 1558-0008
• DOI: 10.1109/JSAC.2024.3365873

The Shortest Distance Path (SDP) problem is a critical routing issue in communication networks, particularly in satellite networks. Typically, SDP is solved by graph-based iterative algorithms, while an explicit or analytic approach is challenging. However, considering the orbit dynamics and topology regularity, this paper proposes, for the first time, an explicit analytic phase-based algorithm StepClimb to directly solve the SDP in low-Earth orbit (LEO) satellite networks. Based on the relationship between satellite phase and inter-satellite link distance, the SDP is modeled with the satellite phase, and SDP problem is converted into a total phase offset problem through theoretical derivations. Then StepClimb is derived in two cases, respectively. Monte-Carlo simulations verify StepClimb's accuracy, which has zero error in the mono-valley case and has less than 0.1% error in the bi-valley case. The algorithm performs better in larger-scale constellations and can save over 99.4% computational cost compared to Dijkstra algorithm. Further, the SDP pattern and features in Starlink constellation are analyzed. The model proves that most inter-plane hops in the SDP occur successively, and the simulations further indicate that these hops prefer satellites in the higher latitude regions.