VoWiFi Cell Capacity Evaluation Using IEEE 802.11ac for VBR Traffic

The popularity of Wireless Local Area Network (WLAN) is increasing tremendously. Recent research indicates that the number of voice calls accommodated in the IEEE 802.11 a/b/g/n standards supported Access Point (AP) is limited. To enhance the capacity of Voice over WiFi (VoWiFi), we have used variable bit rate (VBR) traffic instead of constant bit rate (CBR) traffic. We have seen that the Voice over Internet Protocol (VoIP) traffic is half-duplex due to a single talk conversation. To avoid the wastage of bandwidth resources, we have used silence suppression, which prevents background noise and generates VBR traffic. In this paper, we have proposed an analytical model to estimate the approximate number of VoWiFi calls possible in IEEE 802.11ac standard AP using VBR traffic. Further, we have used Compressed RTP (cRTP) and Arbitration Inter-frame Spacing (AIFS) in our derived model to improve the VoWiFi cell capacity.