Adaptive contention-window MAC algorithms for QoS-enabled wireless LANs

One of the main problems with the proposed IEEE 802.11e medium access control (MAC) protocol is the rapid drop of saturation throughput when the number of wireless users in the coverage area is large. This paper shows that by manipulating the contention window parameters of the 802.11e MAC, significant throughput gain can be achieved. We present two different adaptive contention-window algorithms that improve the saturation throughput by an order-of-magnitude over the static 802.11e MAC. We verify our results by presenting an analytical algorithm with performance that tracks the optimal saturation throughput.