Comparison of different retransmission strategies for bandwidth efficient hybrid ARQ schemes using turbo codes

In this paper, two classes of retransmission strategies in time-varying mobile radio channels are studied for bandwidth efficient hybrid-ARQ (HARQ) schemes using turbo coded modulation. These schemes combine the power efficiency of turbo codes with the bandwidth efficiency of trellis-coded modulation (TCM) to create an effective hybrid FEC/ARQ system. Different retransmission schemes provide a trade-off in terms of throughput, delay, implementation complexity, and error performance.