Performance analysis of ARQ Go-Back-N protocol in fading mobile radio channels

An ARQ Go-Back-N protocol with unreliable feedback and time-out mechanism is considered. Both the forward and the reverse channels are subject to fading impairments. A threshold model for successes and failures of both packets and feedback information is assumed, and the resulting success/failure processes are modeled as Markovian. Throughput and delay are analytically evaluated. For the fading channel model and this protocol, only simulation results for the throughput are available in the recent literature, whereas delay has not been studied. The match between analytical and simulation results shows that the Markov approximation is indeed very good. The analysis is useful in that it provides a fast and accurate method for throughput and delay evaluations, and can be used to choose design parameters, such as the time-out period. In particular, it is shown that there exists an optimum value for the time-out period that is different from the one commonly assumed in the literature.