Resilient Load Balancing Routing for LEO Satellite Constellations
The incorporation of optical Inter-Satellite Links (ISLs) has allowed Low Earth Orbit (LEO) constellations to evolve into a fully developed mesh network, capable of propagating traffic between any two points of the globe with minor reliance on ground infrastructure. However, the dynamics of their orbital topology, coupled with the uneven distribution of load demand across distinct geographical regions, poses a unique set of challenges for routing traffic entirely through space. In this paper, we present ATLAS (Adaptive Twin-mode Load-balanced Orbital routing Strategy), a hybrid routing approach for LEO networks that effectively distribute traffic load across the constellation, while being robust against failures. The framework primarily utilizes a centralized routing algorithm to proactively compute paths based on the combined factor of existing traffic loads and latencies of individual ISLs. If the data flow encounters failed links during propagation, ATLAS switches to a distributed algorithm that utilizes the orbital geometry of the constellation to reroute around affected regions. Simulation results show that our heuristics significantly outperform other state-of-the-art approaches from the literature in terms of throughput, load balancing, and robustness against link failures, while offering adequate latency performance.