Quality of Service Schemes for IEEE 802.11: A Simulation Study

This thesis analyzes and compares four different mechanisms for providing QoS in IEEE 802.11 wireless LANs. We have evaluated the Point Coordinator Function (which is the IEEE 802.11 mode for service differentiation), Distributed Fair Scheduling, Blackburst, and a scheme proposed by Deng et al. using the ns-2 simulator. The evaluation covers medium utilization, access delay, and the ability to support a large number of high priority mobile stations. Our simulations show that PCF performs badly, and that Blackburst has the best performance with regard to the above metrics. An advantage with the Deng scheme and Distributed Fair Scheduling is that they are less constrained, with regard to the characteristics of high priority traffic, than Blackburst is.