On the scalability of H-ARQ systems in wireless multicast

This paper presents the scalability of H-ARQ systems in wireless multicast networks. We consider a wireless downlink scenario with one transmitter (base-station) that has to reliably deliver the same information to several receivers (user terminals). The channel is block-fading Gaussian. Since the users are completely symmetric and information is the same for all, the optimal delay-unconstrained coding transmission strategy is trivially given by coding at rate as close as desired to the ergodic capacity of the channel. The zero error probability in wireless networks is achieved by using hybrid ARQ protocol based on incremental redundancy (IR)