Recovering from Packet Losses in CCSDS Links

Data unit losses in deep space communications are currently faced using retransmission techniques which are however inefficient due to the large round trip delays. For this reason, the Consultative Committee for Space Data Systems (CCSDS) has recently considered packet erasure correcting codes for inclusion in its recommendations for space data system standards. Erasure correcting codes are expected to replace (or drastically reduce) retransmission requests. Erasure codes operate on packets instead of bits and are usually implemented above at the upper layers of the communication stack. In this paper, the implementation of erasure codes within the CCSDS communication stack is considered. Moreover, a comparison in terms of decoding complexity when using a maximum likelihood (ML) erasure decoder in the Control Center is performed between possible solutions, namely Raptor codes and low-density parity-check (LDPC) codes.