Performance analysis of the enhanced distributed coordination function in the IEEE 802.11e

Recently, the IEEE 802.11 Task Group E is standardizing a distributed access approach, called the enhanced distributed coordination function (EDCF), to support service differentiation in WLANs. In EDCF, service differentiation is achieved by assigning different values of EDCF access parameters (e.g., the minimum contention window, the maximum contention window, and the arbitration interframe space) to different traffic classes. In order to satisfy specific QoS requirements for different traffic classes, a mathematical analysis turns to be helpful to analyze the system performance. In this paper, we provide an analytical model to study the expected bandwidth for each traffic class in EDCF. We validate the accuracy of the model by using the ns-2 simulator. Some performance evaluations are demonstrated in comparison with the IEEE 802.11 legacy MAC protocol. The model can be also used as guidelines for admission control or resource management schemes.