By

In this dissertation, we investigate the issue of Quality of Service (QoS) provisioning for IEEE 802.11 MAC protocols. We propose a multiple class p-persistent version of the IEEE 802.11 protocol to support QoS differentiation in wireless local area networks (WLANs). A theoretical analysis model is proposed to predict the performance of this protocol. Through analytical modeling and simulation, we demonstrate that by assigning appropriate different transmission probabilities to wireless nodes of different classes, it is feasible to provide service differentiation and achieve the targeted throughput ratio among different classes, while at the same time, maximizing the total channel utilization. We also consider several implementation issues to practically implement the proposed work conforming to the IEEE 802.11 standard. In particular, we derive an approximate solution for the analytical model to reduce the computational complexity and estimate the performance deterioration due to such an approximate solution. We point out that as long as the average packet collision period is much longer than the basic slot duration in the back-off algorithm, (which is true in all the 802.11 family standards such as 802.11, 802.11b