Voice capacity of IEEE 802.11b and 802.11a wireless LANs in the presence of channel errors and different user data rates

Abstract

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 and hot spot scenarios. The paper presents new results for the conversational speech capacity of 802.11b and 802.11a WLANs by specifically considering channel errors and different user rates. Our results show that both systems suffer a significant loss in capacity for packet error rates (PER) greater than 5%. We also show link adaptation can prove to be invaluable in coping with higher PERs. Finally, we show that even a limited presence of low data rate users severely limits the overall voice capacity of WLANs.