Analysis of hybrid ARQ protocol with concatenated Reed-Solomon coding in frequency-hop spread-spectrum multiple access communications

This paper presents an analysis of Type-I hybrid ARQ for frequency-hop systems that use concatenated coding and rely on the inner code to erase unreliable dwell intervals prior to decoding the outer code. The analysis incorporates the effects of multiple access interference, symbol interleaving across dwell intervals, multiple codewords per packet, and multiple symbols per dwell interval. Key to the analysis is a method for explicitly determining decoder error and failure probabilities for channels characterized by multiple conditional symbol error and erasure probabilities. Numerical results show that concatenated coding can greatly improve the throughput of hybrid ARQ if the inner code is used to erase unreliable dwell intervals