Path-Diverse Optical Mesh with Erasure Coding (PDOMEC): A Non-Line-of-Sight Tolerant Architecture for Free-Space Optical Inter-Satellite Links

Abstract

Free-space optical links in satellite constellations deliver high bandwidth but are vulnerable to short-duration blockages caused by orbital debris, atmospheric turbulence, cloud cells and pointing jitter. Conventional link-level retransmission (ARQ) fails on long inter-satellite baselines because the propagation delay exhausts buffers and collapses throughput. This paper describes a framing-layer architecture that tolerates such blockages without retransmissions or mechanical re-pointing. Incoming data are collected into fixed-length frames, expanded by erasure coding (Reed-Solomon or rateless fountain codes) with a configurable over-provisioning ratio, and the resulting shards are injected simultaneously across multiple spatially separated optical terminals on the same node. The receiving node reconstructs the original frame at line rate as soon as any K out of N shards arrive, discarding the rest. Transient losses on individual paths are absorbed by the coding redundancy and by the geometric diversity of the optical axes. The method is intended for high-capacity synchronous streams in LEO, MEO, GEO and deep-space optical mesh networks.