Performance of IR-HARQ-based RC-LDPC Code Extension in Optical Satellite Systems

This paper studies the link-layer error-control solutions for low Earth orbit (LEO) satellite-based free-space optical (FSO) communications. Specifically, we address the design of low-density parity check (LDPC) codes for incremental redundancy (IR) hybrid automatic repeat request (HARQ) protocols. To facilitate the IR-HARQ operation, a rate-compatible (RC)-LDPC code family constructed by the code extension method is used. Performance metrics, including goodput and energy efficiency, are investigated. Simulation results confirm the effectiveness of our proposed design compared to existing solutions over the state-of-the-art. The results also support the proper selection of the LEO satellite’s transmitted powers based on the trade-off between goodput and energy efficiency.