Performance Analysis and Algorithm Selection for Reliable Multicast in IEEE 802.11aa Wireless LAN

Legacy IEEE 802.11 does not efficiently support multicast transmissions. To cope with the increasing demand for multicast, which is mainly required to deliver multimedia traffic, the IEEE 802.11aa Task Group has recently standardized new mechanisms for allowing efficient and robust transmission of multicast flows in wireless local area networks (WLAN). However, the standard allows the use of different mechanisms for this purpose, and leaves open the choice of which one to use for a given scenario. In this paper, we present an analytical model for evaluating the performance of the mechanisms included in the 802.11aa standard and then compare their performance. Our analysis shows that there is no absolute winner out of these mechanisms and performance strongly depends on the scenario. Building on our model, we then propose a novel algorithm that selects the best multicast mechanism to use as a function of the scenario conditions. Our results are validated by extensive simulations.