Satellite-Terrestrial Routing or Inter-Satellite Routing? A Stochastic Geometry Perspective

TL;DR

This paper compares satellite-terrestrial routing and inter-satellite routing in low Earth orbit constellations, proposing optimal relay algorithms and analyzing their performance to inform better constellation design.

Contribution

It introduces two optimal relay selection algorithms for STR and ISR, with analytical expressions for their availability and energy efficiency, enhancing routing performance analysis.

Findings

ISR has shorter signal propagation distances than STR.

Proposed algorithms improve energy efficiency and availability.

Insights assist in optimizing satellite constellation design.

Abstract

The design and comparison of satellite-terrestrial routing (STR) and inter-satellite routing (ISR) in low Earth orbit satellite constellations is a widely discussed topic. The signal propagation distance under STR is generally longer than that under ISR, resulting in greater path loss. The global deployment of gateways introduces additional costs for STR. In contrast, transmissions under ISR rely on the energy of satellites, which could be more costly. Additionally, ISLs require more complex communication protocol design, extra hardware support, and increased computational power. To maximize energy efficiency, we propose two optimal routing relay selection algorithms for ISR and STR, respectively. Furthermore, we derive the analytical expressions for the routing availability probability and energy efficiency, quantifying the performance of the algorithms. The analyses enable us to assess the performance of the proposed algorithms against existing methods through numerical results, compare the performance of STR and ISR, and provide useful insights for constellation design.