Bounds on the throughput performance of ARQ Go-Back-N protocol in Markov channels

An ARQ Go-Back-N protocol with unreliable feedback and time-out mechanism is considered. Both the forward and the reverse channels are subjected to a Markovian error structure. Previous results for the throughput performance of such protocol are discussed and shown to provide an upper bound to the actual performance. A new lower bound is derived and shown to be tighter than the upper bound available in the literature, in the presence of long bursts of errors. The analysis is carried out following two equivalent approaches, namely the transfer function method and a Markov chain technique. The latter is shown to be more powerful, without additional complexity. The theory is applied to the study of the throughput performance of the protocol on a mobile radio channel: simulation checks show that our approach is very accurate.