An Innovative Rate Adaptation Algorithm for Multicast Transmissions in Wireless LANs

Rate adaptation represents a key functionality of the 802.11 MAC protocol for performance enhancement. Several solutions have been proposed for improving the transmission rate of unicast communications using frame receptions/losses, BER (Bit Error Rate) and SNR (Signal to Noise Ratio) measurements. Nevertheless, rate adaptation for multicast transmissions represents a more challenging tasks due to the complexity of estimating the reception correlation of wireless links. This paper presents a novel scheme for selecting the best transmission rate for multicast communications using the packet reception correlation of the links established among the nodes of the multicast group with the access point. The proposed algorithm has been evaluated on a real-life testbed using commercial wireless cards. The results show that our solution accurately estimates the reception correlation of wireless links, thus considerably increasing the performance of multicast transmissions up to 3x and 5x in terms of throughput and delay, respectively.