QoS Support in Wireless LANs Using Dynamic Adaptation of Channel Access Parameters

摘要

Service differentiation can be achieved at the MAC layer of IEEE 802.11 wireless LANs by using different channel access parameters (CAPs) for each traffic class. These parameters can be chosen either a priori (using fixed CAPs) or dynamically. However, the a priori approach cannot provide assured QoS and optimal performance. We propose a dynamic approach called Smart Enhanced Distribution Coordination Function (SEDCF), which is based on the EDCF introduced in the upcoming IEEE 802.11e standard. With SEDCF, the Access Point exploits a novel algorithm to dynamically find optimal CAPs based on traffic load in each class, and then periodically advertises these CAPs to wireless stations through beacon frames. Our performance evaluation of SEDCF demonstrates that it can satisfactorily support assured QoS for real-time applications.