Establishing how many VoIP calls a wireless LAN can support without performance degradation

The use of Voice IP (VoIP) over wireless local area networks (WLAN) is a topic of great interest in the research arena. This paper attempts to answer the question: how many VoIP calls can be established over a WLAN 802.11b network before the call quality becomes unacceptable?In order to answer the question we carried out a large number of simulations of both infrastructure and ad-hoc networks, with different background traffic conditions. In each case we measured the key performance criteria: packet delay, jitter and lost-packet rate. This paper presents some of the key results and provides a number of answers, depending on the precise conditions. It turns out that for infrastructure networks it is unlikely that more than 5 VoIP calls can be supported before some of the calls experience unacceptable performance limitations. For ad-hoc networks the situation is less clear, as it depends very much on the exact routing used. However the likely limit is similar