On the utility of rate adaptation for broadcast/multicast media traffic in 802.11 networks

Abstract

As there is no MAC layer acknowledgment from the receiver for broadcast/multicast transmission in the 802.11 network, using the lowest transmission rate is understandably the safest approach because it minimizes reception error for clients with the worst channel condition. On the contrary, the transmission rate for receivers with good channel conditions is unnecessarily limited. In the case of video streams being broadcast/multicast via 802.11, this approach will lead to poor received video at all clients. In this paper, we demonstrate that there isutility in activating rate adaptation for broadcast/multicast traffic. In particular, we implement a system that significantly improves the broadcast video quality in 802.11 network. This is achieved through an approach of joined broadcast/multicast rate adaptation and network-coded retransmission.