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A Fuzzy Adaptation Method for Improving Link Utilization and Reducing Network Delays in IEEE 802.11eWireless Ad Hoc Networks
Joe Naoum-Sawaya and Bissan Ghaddar

IEEE 802.11e is being researched to provide Quality of Service (QoS) for the upcoming multimedia applications in broadband wireless networks. It’s a contention based channel access mechanism that uses the enhanced distributed channel access (EDCA) technique. EDCA statically resets the Contention Window (CW) after each successful transmission. This behavior fails to adapt to network conditions leading to poor link utilization and increasing network delays. This article discusses a novel technique that utilizes fuzzy logic to adapt the CW values. In contrast to other adaptation techniques that utilize crisp data to quantify channel conditions, this method utilizes linguistic terms that accurately model uncertainty through the use of fuzzy logic. The aim of this method is to provide an improved and consistent link utilization, both factors being important for delay sensitive and real time applications. The performance of the proposed fuzzy adaptation technique is compared to the original IEEE 802.11e differentiation scheme in addition to other adaptation techniques. Conducted simulations revealed remarkable adaptation ability reflected in better and more consistent performance most notably for streaming applications.

Keywords: Enhanced Distributed Channel Access, IEEE 802.11e, Quality of Service,Wireless LAN, Fuzzy Logic.

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