IEEE 802.11e develops Enhanced Distributed Coordination Access (EDCA) and Hybrid Coordination Function (HCF) controlled channel access (HCCA), to enhance the Quality of Service (QoS) of the original MAC mechanism. However, the priority-based access mechanism can not guarantee QoS requirements in terms of delay and throughput since it is contention-based. In this paper, we propose several schemes that regulate backoff contention window adaptively to achieve more fairness between ACs. The simulation results present the constraint due to agreement level. Moreover, it is demonstrated that the proposed schemes can assign transmission opportunity more fairly than EDCA. Also the proposed schemes really have a performance improvement [1-2].