Voice capacity of IEEE 802.11b, 802.11a and 802.11g wireless LANs

IEEE 802.11 based wireless local area networks (WLANs) are becoming popular in home, enterprise and public access areas primarily due to their low cost, simplicity of installation and high data rates. While WLANs continue to be predominantly data centric, there is growing interest in using WLANs for voice, especially in enterprise markets. This paper presents new analytical and simulation results for the conversational speech capacity of WLANs and compares the different WLAN technologies in that regard. Specifically, we consider IEEE 802.11b, 802.11a and 802.11g systems in the infrastructure mode and find that voice capacity is a strong function of the channel bandwidth, codec packetization interval, data traffic and the packet size used by data. For the IEEE 802.11g system, we find that capacity depends on the CTS-to-self and RTS-CTS legacy protection mechanisms, with the RTS-CTS mechanism achieving lower capacity. We show that the analytical results are in close agreement with those from simulations and conclude the paper by highlighting some key factors that dictate the capacity of WLANs.