Packet combining in frequency-hop spread-spectrum communication systems

The performance of frequency-hop spread-spectrum (FHSS) communication systems using hybrid automatic-repeat-request (ARQ) can be improved by combining current and prior transmissions at the receiver. Two methods for combining packets in systems that employ interleaving and Reed-Solomon (RS) coding are presented and analyzed for the partial-band interference channel. These methods use majority logic combining at the codeword level to make retransmission decisions. Bounded distance errors-and-erasures decoding and erasure generation by means of Viterbi´s ratio threshold test (RTT) are incorporated in the analysis. Results of the analysis show that, with comparable packet error probabilities, the packet-combining schemes provide significant gains in throughput when compared with systems that do not employ combining