VoIP over WLANs by Adapting Transmitting Interval and Call Admission Control

VoIP over wireless local area network (WLAN) is an important application of WLAN and gaining more and more attention. In this paper, we analyze the maximum number of VoIP calls in WLAN and propose a new call admission control strategy, namely, adaptive transmitting interval call admission control (ATICAC) to enhance VoIP calls in 802.11 WLANs. In ATICAC strategy, base station (BS) adaptively changes the transmitting interval of the active stations to prevent the network from saturation by controlling the average collision probability pc of the network. The proposed model is in good agreement with our simulation results. ATICAC can not only ensure the QoS of VoIP calls in 802.11 WLANS in the network, but also increase the number of VoIP calls in the network.