Dual queue based rate selecting schedule for throughput enhancement in WLANs

In IEEE 802.11 WLANs, a fixed low transmission rate is used for multicast transmissions regardless of channel conditions of receivers. This may lead to inefficient use of wireless channel, especially when access point (AP) has both unicast and multicast data frames in the transmission queue. In this paper, we propose a dual queue based rate selecting schedule scheme for efficient use of wireless channel. In contrast to the legacy WLAN AP having a single FIFO queue, AP in the proposed scheme maintains two separate queues at the AP, one for unicast data and another for multicast data. When the AP accesses wireless channel, it decides a type of data (unicast or multicast) and transmission rate to be sent according to the channel condition and the delay boundary of multicast data. Our simulation results show that the proposed scheme increases the average data rate and energy consumption saving up to 13.7% compared to the auto rate fallback (ARF) which determines the transmission data rate only considering the channel condition.