Distributed Delay Estimation and Call Admission Control in IEEE 802.11 Wireless LANs

Voice over WiFi (VoWiFi) will soon be the main alternative to cellular phones. Providing a satisfactory user experience remains difficult, however. We focus on call admission control (CAC) for both constant bit rate (CBR) and variable bit rate (VBR) VoIP traffic. Our approach is based on measuring the time between idle times. It requires no infrastructure changes, adds no probing traffic and has low complexity. We demonstrate through extended simulations that our approach achieves very good accuracy for both delay estimation and CAC when only VoIP sources are present and when both VoIP sources and data sources are present. Furthermore, we confirm TBIT performance through experiments.