A Reactive Approach to QoS Provisioning in IEEE 802.11e WLANs

IEEE 802.11e provides basic mechanisms for traffic differentiation in WLANs previously unavailable with the IEEE 802.11 standard. The enhanced distributed channel access (EDCA) is probably the most promising subset of such mechanisms, and it is already implemented in a huge number of Network Cards. In this paper we present an algorithm for the provisioning of QoS in EDCA WLANs. The algorithm is based on monitoring and reactive configuration of EDCA mechanisms in scenarios where voice over IP (VoIP) and best effort (BE) applications concurrently access the wireless channel. Results obtained in a real test-bed prove the effectiveness of the algorithm both in protecting VoIP communications and in providing minimal quality levels and fairness to BE applications.