Recent Findings on Erasure Codes for Space Communications

Abstract

Implementation of automatic repeat request strategies is the main reliability option available in the Consultative Committee for Space Data Systems protocols to support data communications in deep-space missions. The large latency often experienced in such scenarios, however, penalizes the efficiency of retransmissions, making the overall applicability of automatic repeat request problematic. On the contrary, the use of erasure codes is a more appealing solution to mitigate packet losses. In this regard, preliminary studies on the use of binary low-density parity-check codes under maximum likelihood/iterative decoding have already shown the performance benefit they can bring with respect to traditional schemes based on retransmissions. This paper extends the analysis conducted in previous studies toward non-binary low-density parity-check codes. Performance assessment is carried out with respect to reliability metrics (codeword error rate) and encoding/decoding complexity. Finally, the integration of erasure codes into the Consultative Committee for Space Data Systems protocol stack is discussed, by presenting the implementation in the Licklider Transmission Protocol.