Two-Tier Cooperative Routing Leveraging GSL Diversity for Large-Scale LEO Satellite Networks

Abstract

Nowadays, the fast development of large-scale low Earth orbit (LEO) satellite networks has been pushing for highly-efficient routing schemes that can realize quality-of-service (QoS) aware routing adaptively. However, the dynamic nature of LEO satellite networks and the capacity mismatch between their inter-satellite links (ISLs) and ground-satellite links (GSLs) make QoS-aware routing very challenging. In this work, we propose a two-tier cooperative routing framework (namely, 2T-CoR) to leverage GSL diversity and deflection routing for effectively relieving congestion, thereby improving QoS parameters such as packet loss rate and end-to-end (E2E) latency. We first develop a time-sliced model to utilize the orbital periodicity of LEO satellite networks for accelerating their routing calculations. Then, a two-tier cooperative routing algorithm is designed to seamlessly synergize orbital periodicity with GSL-state awareness to efficiently reduce congestion as well as improving GSL utilization. Extensive simulations with a constellation of $3,840$ LEO satellites verify the effectiveness of our proposal over the state-of-the-arts.