The provision of QoS in IEEE 802.11 Wireless LANs has recently become a research focus.Based on the previously proposed mechanism
a new self-adaptive algorithm with QoS guarantee on IEEE 802.11 wireless LAN is proposed.This new algorithm tunes the initial contention window of different priority stations dynamically to decrease the unnecessary collisions and achieves the optimal resource utilization.High priority stations and low priority stations are assigned different self-adaptive parameters to guarantee the QoS property of high priority stations.Numerous simulation results have been shown about the performance of the new mechanism.