Macro diversity combining schemes for multicast transmission in high-speed cellular networks
Résumé
In this paper, we study the transmission of data destined for several users on the radio interface using the multicast mode, an interesting alternative of the conventional unicast mode. In the multicast mode, a packet is sent simultaneously to several terminals in the same cell. We consider different techniques of macro diversity, namely Selective Combining (SC) and Maximal Ratio Combining (MRC). We develop an analytical model that allows the computation of the mean bitrate for both multicast and unicast schemes. We use a scheduler that allocates bandwidth to mobiles according to their instantaneous channel quality. In this context, we propose an efficient user clustering considering their average radio channel quality. The study shows that macro diversity improves the transmission performance especially for pure multicast.