Experimental VoIP capacity measurements for 802.11b WLANs

There is an increasing interest in supporting voice over IP (VoIP) applications over wireless local area networks (WLANs). To provide quality of service guarantee to voice traffic, an admission control mechanism must be administered to avoid over loading the network. In this paper, we present an experimental evaluation of VoIP capacity in WLANs under various data and voice loads. The obtained capacity estimates can be used in admission control engine to make an admission or a rejection decision. In this paper, we identify a suitable evaluation metric to quantify the performance of a voice call. The metric accounts for packet losses and packet delays for each voice flow. We then define voice capacity in a WLAN and present experimental capacity measurements under various background data traffic loads. The experimental capacity measurements are immediately useful for WLAN hotspot providers and enterprise WLAN architects.