A New Adaptive EDCA Scheme for Improving the Performance of IEEE 802.11s Network

In the IEEE 802.11s draft, the Enhanced Distributed Channel Access (EDCA) of 802.11e is totally adopted as the Medium Access Control (MAC) scheme of Wireless Mesh Network (WMN). Regardless of the network´s condition, the value of every data traffic´s Contention Window (CW) and the policy of resetting CW after a successful transmission or collision are both fixed. So the EDCA is not completely suitable for WMN which has numerous nodes, flexible topology and complex environment. EDCA of 802.11e was improved by some scholars and an Adaptive EDCA (AEDCA) was proposed to make the CW change according to the collision probability in the network. In this paper, a New Adaptive EDCA (N-AEDCA) based on AEDCA was proposed, which is more suitable for the 802.11s wireless mesh network. In N-AEDCA, the Frame Error Rate (FER) and the average collision probability are introduced, so that CW can be changed more slowly according to the network´s condition and different data categories. The simulation results show that it helps to ensure the Quality of Service (QoS), reduce the packets loss rates and increase the total throughput of the network.