A novel scheduling scheme to enable voice packet transmission with PCF over an IEEE 802.11 wireless LAN

PCF is the access method in IEEE 802.11 designed for real-time traffic transmission. However, the traditional round robin scheduling scheme cannot guarantee the delay and dropping probability for the voice packet under heavy load conditions. Thus, we propose a novel PCF polling scheme, named priority round robin (PRR), in this paper. By this novel scheduling scheme, the performance of the average delay and dropping probability of the voice packet is greatly enhanced. The average voice packet delay keeps about 20 to 30 ms, and the dropping probability is below 1% even in heavy load conditions. At the same time, the decrease of system throughput, the price of the performance improvement, is very little under heavy load conditions if parameter PollFailMax is carefully selected, which means that our scheduling scheme is very efficient.