An dynamic grouping algorithm for MPEG-4 video multicast over WLANs

Over the IEEE 802.11 WLANs, the basic (lowest) data rate is used for multicast. In this way, it guarantees all members of the multicast group can properly receive the packets. However, in video multicast applications, this way will heavily penalize those group members who are capable of receiving data packets at higher rates and also will reduce the overall network throughput. In this paper, we propose a dynamic grouping algorithm for video multicast. This scheme dynamically groups members according to their different time-varying receiving capabilities. By selecting an optimal grouping strategy using dynamic programming, we show that the overall multicast throughput can be maximized. We analyze the performance of the proposed multicasting algorithm by simulations in NS-2 platform. Our results show that the performance of overall system and the QoS of the members with higher receiving capabilities can be greatly improved by dynamic grouping multicast algorithm.