Reliable data delivery using packet coding over acoustic links

Acoustic links are challenged by high bit error rates, which cause data packets to be declared as erroneous. To prevent the packet loss and achieve reliable data transmission over such links, some form of feedback must be implemented to deliver acknowledgments from the receiver to the transmitter, thus initiating re-transmission of erroneous packets. Conventionally, data packets are grouped and a selective acknowledgment procedure of the stop-and-wait type is employed as a suitable solution for half-duplex acoustic links. We re-visit the issue of reliable data transmission and investigate the use of random packet coding in conjunction with a selective acknowledgment procedure. Specifically, we introduce random packet coding, and regard a block of coded packets as an equivalent of a packet—now termed the super-packet. We then form groups of super-packets and apply a selective acknowledgment procedure on the so-obtained units. Analytical results, obtained with experimentally verified channel models, demonstrate the power of grouped packet coding which offers a much improved throughput-delay performance on randomly time-varying acoustic channels with long delays.