A hybrid-ARQ protocol using channel output feedback

In recent years, hybrid-automatic repeat request (ARQ) protocol has become one of the most popular packet transmission schemes. Hybrid-ARQ aims to combine the advantages of forward error correction codes with the traditional ARQ scheme to increase the reliability and throughput of the network. In this paper, we look at improving upon this performance for block fading channels (e.g., Rayleigh, Rician, etc.) by using feedback information from the destination; in particular, using a turbo code in conjunction with a proposed linear feedback code under additive white Gaussian noise. The scheme is developed for the general case of multiple antennas at both the transmitter and receiver, and is analyzed for varying amounts of feedback information sent from the destination to the source. Simulations are presented to illustrate the gains in throughput offered by the proposed scheme over the existing ones.