On the performance of hybrid ARQ with diversity combining over ideally interleaving flat Rayleigh channels

The performance of hybrid automatic repeat request (ARQ) with diversity combining over an ideally interleaved flat Rayleigh channel is investigated. Instead of evaluating the joint probability density function of the sum of multiple Rayleigh random variables, a simple method is proposed to analyze the square of the sum, and the pairwise error probability can therefore be evaluated, yielding the lower and upper bounds of the probability of error for hybrid ARQ with diversity combining. It is shown that the diversity combining contributes to the increased diversity order, which is validated by both numerical analysis and simulation results.