Performance of hybrid ARQ schemes for the fading channel

We define and adopt a theoretical method, based on the sphere-packing bound, for evaluating and comparing the achievable performance of different hybrid automatic repeat request schemes for the fading channel. The channel state evolution is assumed to be represented by a finite-state Markov chain. To assess the correctness and the accuracy of the analysis, some simulation results, based on the use of turbo codes, are also presented.