Adaptive channel access tuning and QoS support for multimedia applications over IEEE 802.11e WLANs

IEEE 802.11e Enhanced Distributed Channel Access (EDCA) standard defines multiple Access Categories (AC) to support MAC-level Quality of Service (QoS). However, the values of the main parameters of each AC are static and do not take the wireless channel condition and the channel density into account. Therefore, the default EDCA parameters only yield good performance for few scenarios. In this paper, we propose a new cross-layer adaptation scheme that improves the IEEE 802.11e Quality of Service (QoS) by tuning the Medium Access Control (MAC) layer channel access parameters. Proposed scheme is based on the number of mobile nodes on the channel, their traffic types, application layer QoS requirements and physical layer (PHY) channel conditions. Simulation results indicate that our scheme outperforms the standard implementation and provides desired QoS for multimedia applications.