Performance of hybrid ARQ schemes using turbo trellis coded modulation for wireless channels

In this paper, bandwidth efficient Type-I and Type-II hybrid-ARQ (HARQ) schemes using turbo trellis coded modulation (TTCM) are proposed. 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. Several packet combining schemes are presented for use in conjunction with iterative turbo decoding over wireless time-varying Rayleigh fading channels. The packet combining schemes provide improved throughput and reliability compared to a standard Type I hybrid ARQ system without combining with only a small increase in transmitter and receiver complexity. Simulation results show that, for high throughput values, HARQ schemes based on TTCM give substantial improvement over conventional TCM schemes with the same throughput over wireless channels.