Admission control of VoIP calls in EDCA WLANs: Analysis and experimentation

The Enhanced Distributed Channel Access (EDCA) is a component of the new IEEE 802.11e standard [2], which introduces Quality of Service (QoS) support in Wireless LANs (WLANs). This paper proposes a model for the VoIP capacity of an EDCA WLAN. The proposed solution decouples the problem of estimating stations performance and that of evaluating channel congestion. Moreover, it models the dynamics of the sending queues. This translates in a model working under generic load conditions (i.e. VoIP traffic at different bit rates) that captures the impact of all the parameters introduced by EDCA. To validate the model, we derived a simple Admission Control algorithm for VoIP and generic real-time symmetric applications. Experimental analysis and simulations have been used to validate the model and to establish its limitations.