Reliable Multicast via Satellite

An existing hybrid error control protocol that combines packet level parity retransmissions with ARQ type feedback was studied under a variety of different conditions. Additionally, several modifications were made to the protocol and their performance in terms of bandwidth and delay were studied. The protocols were studied both with and without local recovery schemes. For non-local recovery schemes, the use of autoparity wasexamined and was shown to decrease recovery latency at the cost ofadditional bandwidth usage. The effects of different estimation schemes coupled with autoparity usage were investigated and results were compared. Simplistic adaptive mechanisms where the parity provided during each transmission is adjusted based upon observed packet loss statistics used with a local recovery scheme were found to offer the best overall results in terms of reducing recovery latency and satellite bandwidth usage.