Voice Capacity Analysis and Enhancement in Wireless LAN

Effective support of VoIP over Wireless LAN (WLAN) remains a crucial challenge for the last-mile wireless coverage of IP networks with mobility support. Due to the limited bandwidth available in a WLAN, an accurate analysis of voice capacity in such a network is critical for the efficient usage of WLAN´s resources. The available upper or lower bound models on voice capacity may significantly overestimate or underestimate a WLAN´s capacity to support VoIP, thus they are not suitable for above purpose. In this paper, we focus on the voice capacity analysis of a single wireless 802.11(a/b) network cell running the distributed coordination function (DCF). In particular, by taking into account the spatial distribution of clients, we propose a more accurate analytical model to estimate the average voice capacity of such a network cell. We further show that by properly exploring the clients´ spatial distribution information in allocating the access points, we may be able to increase the overall voice capacity. The efficiency of our new voice capacity model and new access point allocation scheme is validated through simulation and comparisons with available ones.