A simple packet retransmission strategy for throughput and delay enhancement on power line communication channels

A new communication protocol is developed and evaluated for use on power line distribution networks. The protocol involves retransmission of unacknowledged packets, which are sent in either single or multiple (N) copies in accordance with estimates of communication link quality. Multiple packet copies can be code-combined at the receiver using majority voting on each bit position in order to reduce packet error rates. Adaptive link quality estimates are based on the receipt or absence of positive acknowledgements. Information throughput efficiency is calculated and N optimized in terms of system variables. The performance benefits of code combining are demonstrated. The algorithm is implemented and tested using a five-station intrabuilding power line communications network operating at 1.2, 2.4, 4.8 and 9.6 kbit/s data rates. Substantial throughput and delay improvement occur on poor quality links without degrading performance on good links.<>