Modulating Retroreflectors for CubeSat Optical Inter Satellite Links: Modeling, Optimization, and Benchmarking

TL;DR

This paper presents a comprehensive model and optimization framework for retroreflector-based optical inter-satellite links in CubeSats, demonstrating improved performance and lower power consumption compared to existing solutions.

Contribution

It introduces a unified statistical channel model for MRR-enabled OISLs, along with optimization and benchmarking against state-of-the-art CubeSat laser terminals.

Findings

Optimized MRR-based transmitters outperform OCSD at ranges below 500 km.

Achieve comparable performance to OSIRIS4CubeSat with significantly less power.

Model captures pointing losses and noise, enabling system performance evaluation.

Abstract

Modulating retroreflectors (MRRs) offer a promising pathway to low-complexity and energy efficient asymmetric optical inter-satellite link (OISL) for small spacecrafts, such as CubeSats. In this paper, we develop a unified statistical channel model for an on off keying modulated, retroreflector-enabled OISL. The model captures both stochastic and deterministic pointing losses, as well as signal-dependent noise. Stochastic channel distributions are approximated via Monte Carlo simulation, and system optimization is carried out under CubeSat constraints using the achievable information rate as the primary metric. In addition, we derive bit-error ratio and outage probability to evaluate communication reliability. The proposed architecture is benchmarked against three state-of-the-art CubeSat laser terminals, i.e., NASA's Optical Communications and Sensors Demonstration (OCSD), DLR's OSIRIS4CubeSat, and NASA's CLICK BC. Results indicate that an optimized MRR-based transmitter can outperform OCSD and achieve performance comparable to OSIRIS4CubeSat at ranges below 500 km, while consuming only 2.5 W of power during transmission, significantly less than conventional CubeSat optical terminals.