Performance analysis of satellite HARQ under partial feedback conditions

Non-terrestrial networks (NTNs) have emerged as a key enabler for achieving ubiquitous, seamless, and continuous connectivity, especially following the inclusion of satellite communication in the 5G ecosystem by the 3GPP starting with Release 17. This integration poses significant challenges, particularly in adapting terrestrial mechanisms such as the hybrid automatic repeat request (HARQ) protocol to the satellite environment, where significant round-trip delays prevent its straightforward application. In this work, we investigate the performance of HARQ in satellite communication scenarios under three feedback configurations: fully enabled, fully disabled, and partially disabled. We propose a novel approach for the partially disabled case, employing optimal erasure coding to reduce feedback overhead while improving transmission efficiency compared to the fully disabled configuration. Through analytical evaluation and simulations, we highlight the key trade-offs and performance metrics of the system across the various configurations studied.