Performance Evaluation of Selection Strategies for Inter-Satellite Paths in Walker-Delta Constellations

Abstract

In LEO satellite constellations, traffic between a user terminal and a gateway is carried over a satellite path. As the satellite constellation rotates around Earth, a new path must be reselected repeatedly from a set of path candidates. In this paper, we study the impact of path selection strategies on several metrics: path length in terms of Euclidean distance and hop count, path-change rate, and rate of used links. These metrics are relevant because they affect either communication latency or the complexity of control and resource management. We explain how path candidates are generated, define three heuristic path selection strategies, and evaluate them over a large set of UT-GW scenarios within a single shell of a Walker-Delta constellation with 1,156 satellites. Overall, the results show that path selection has a significant impact on both latency-related metrics and path churn.