Performance Analysis and Optimization of the 802.11e EDCA Transmission Opportunity (TXOP) Mechanism

摘要

The IEEE 802.11 Task Group E is working on a QoS-aware MAC protocol involving Enhanced Distributed Channel Access (EDCA). This scheme was developed to offer QoS capabilities to WLAN, offering significant im- provements to multimedia traffic. MANETs will also bene- fit from this new technology since the most widely deployed and used wireless cards are those based on IEEE 802.11. The use of transmission opportunity (TXOP) EDCA differ- entiation parameter, received a little attention in the previ- ous analytical studies in contrast to the contention window size-based differentiation mechanism. In this paper, an an- alytical model is proposed to study and optimize the TXOP bursting transmission scheme. We expose formulates for saturation throughput, delay, and frame-dropping of dif- ferent priority classes. The analysis allows us to derive the optimal durations of the packet bursting regarding ap- plication and network load parameters. We validate the accuracy of our model through ns-2 simulations.