Error Recovery Service for the IEEE 802.11B Protocol

We develop a service that allows the current IEEE 802.11b MAC protocol to perform dynamic packet sizing and forward error correction. Our service, called ERSMAC, is designed to allow the deployment of the IEEE 802.11b protocol in industrial environments characterized by high BER and fast time variation. ERSMAC uses a maximum likelihood estimate of the BER to solve for the optimal packet size that maximizes the success probability of transmissions while minimizing the overhead cost. ERSMAC also implements an adaptive forward error correction scheme using Reed-Solomon code such that every retransmission attempt has a higher probability of success than the previous attempt due to its association with a stronger RS code. Finally, we show, through simulations, that ERSMAC outperforms the original unmodified IEEE 802.11b protocol in terms of average throughput, average delay and efficiency.