On the capacity of cooperative diversity systems with adaptive modulation

In recent years, cooperative diversity systems have gained increased attention in the literature as a new way of combating the effect of signal fading. In this paper, we investigate the performance of these systems when adaptive modulation is used. More specifically, we consider the case of optimal instantaneous power and rate adaptation, optimal power adaptation with constant power, and truncated channel inversion adaptation, and study the performance of both regenerative and non-regenerative systems under Rayleigh type of fading. The performance criteria used is the channel capacity which is the maximum rate of data transmission at an arbitrarily small bit error rate.