A New Call Admission Control Algorithm for VoIP in IEEE 802.11 Wireless LANs

Abstract

In the past few years, the IEEE 802.11 WLAN has become very popular and widely deployed for Internet access. On the other hand, voice over IP is one of the fast growing Internet applications today. Thanks to the convergence of these two trends, it is believed that VoIP over WLAN is expected to become an important Internet applications. In this context, the so called “avalanche effect” has been identified as a real problem in a WLAN network, when operating near its capacity limit, in which the admission of an additional call may result in unacceptable QoS for all the ongoing VoIP connections. Therefore, this work proposes a new call admission control mechanism, based on the access point’s transmission buffer utilization ratio, to mitigate this problem. The obtained results show that the proposed mechanism mitigates the “avalanche effect”, leading to stable service operation, acceptable QoS levels and significant capacity gains considering tested scenarios.