Site Diversity in Downlink Optical Satellite Networks Through Ground Station Selection

TL;DR

This paper explores ground station selection in downlink optical satellite networks, deriving performance metrics and analyzing diversity gains to improve reliability and efficiency of laser SatCom systems.

Contribution

It introduces a ground station selection scheme for laser SatCom, providing closed-form performance expressions and insights into site diversity and aperture effects.

Findings

Derived outage probability and ergodic capacity expressions.

Quantified site diversity gain through asymptotic analysis.

Demonstrated the impact of aperture size on system performance.

Abstract

Recent advances have shown that satellite communication (SatCom) will be an important enabler for next generation terrestrial networks as it can provide numerous advantages, including global coverage, high speed connectivity, reliability, and instant deployment. An ideal alternative for radio frequency (RF) satellites is its free-space optical (FSO) counterpart. FSO or laser SatCom can mitigate the problems occurring in RF SatCom, while providing important advantages, including reduced mass, lower consumption, better throughput, and lower costs. Furthermore, laser SatCom is inherently resistant to jamming, interception, and interference. Owing to these benefits, this paper focuses on downlink laser SatCom, where the best ground station (GS) is selected among numerous candidates to provide reliable connectivity and maximum site diversity. To quantify the performance of the proposed scheme, we derive closed-form outage probability and ergodic capacity expressions for two different practical GS deployment scenarios. Furthermore, asymptotic analysis is conducted to obtain the overall site diversity gain, and aperture averaging is studied to illustrate the impact of aperture diameter on the overall performance. Finally, important design guidelines that can be useful in the design of practical laser SatComs are outlined.