Optimal Rate-Diversity-Delay Tradeoff in ARQ Block-Fading Channels

We consider coded modulation schemes for the automatic-repeat-request (ARQ) block-fading channel. We show that the optimal SNR exponents of these schemes are given by a modified form of the Singleton bound that includes the effects of code rate and maximum ARQ delay. The role of maximum distance separable (MDS) codes over the ARQ block-fading channel is investigated and simulation results are presented, demonstrating that practical MDS codes achieve the optimal SNR exponent dictated by the Singleton bound