Date Added: Jul 2009
One of the key challenges in designing a Quality of Service (QOS) scheme for IEEE 802.11 Wireless LANs (WLANS) is reducing collisions and improving throughput. Existed Adaptive contention windows mechanisms can reduce collisions of all traffic. However, adaptive contention window algorithms cannot guarantee the absolute priority of the high-priority traffic. Especially in the heavy loading, low-priority traffics will introduce unnecessary collisions and cause unsuccessful transmission. The authors' scheme aims to share the transmission channel efficiently and to provide the absolute differentiated traffic scheme. Relative priorities are provisioned by adjusting the range of the back-off timer of low-priority traffic class taking into account both applications requirements and network conditions.