Voice over Internet Protocol over IEEE 802.11 Wireless Local Area Networks and effective admission control with transmission interval adaptation

Voice over Internet Protocol (VoIP) over Wireless Local Area Networks (WLANs) is an important application of WLANs and it has gained more and more attention recently. In this article, we analyse the maximum number of VoIP calls supportable in a WLAN and propose a new call admission control strategy, namely, Adaptive Transmission Interval Call Admission Control (ATICAC) to enhance VoIP calls in 802.11 WLANs. In ATICAC strategy, Base Station adaptively changes transmission interval of the active stations to prevent the network from saturation by controlling the average collision probability of the network. The proposed model gives a very good agreement with our simulation results. ATICAC can not only ensure the Quality of Service (QoS) of VoIP calls in 802.11 WLANs in the network, but also increase the number of VoIP calls in the network.