Admission Region of Multimedia Services for EDCA in IEEE 802.11e Access Networks

This paper presents a simulation analysis for the evaluation of the admission region of a IEEE 802.11e network adopting the EDCA (Enhanced Distributed Channel Access) mechanism. In particular, this study gives an estimate of the number of QoS-aware applications, namely videoconference and Voice over IP (VoIP), that can be admitted to the transport service offered by the EDCA while satisfying their QoS requirements. The traffic sources adopted for the simulation are obtained from measurement campaigns led on the emulation of VoIP and videoconference services based respectively on the G.723.1 and the H.263 codecs. The results emphasize the bottleneck role played by the Access Point when services producing symmetrical traffic are conveyed over an 802.11e access network. Furthermore, the QoS parameters experienced in a mix of VoIP, videoconference and TCP traffic under EDCA are compared with those obtained when the DCF mechanism is adopted. This comparison clearly highlights the efficiency in traffic differentiation of the EDCA algorithm.