VoWiFi Cell Capacity Evaluation using WiFi 7 considering VBR Traffic

Abstract

The need for Wireless Local Area Network (WLAN) technology is experiencing substantial growth. The transmission of Voice over WiFi (VoWiFi) is half-duplex due to its single-talk nature. In order to mitigate the inefficient utilization of available bandwidth, the technique of silent suppression is employed. This feature decreases the level of ambient noise and provides Variable Bit Rate (VBR) communication. To enhance the VoWiFi cell capacity, we utilized VBR traffic instead of Constant Bit Rate (CBR) traffic. In this study, we developed a mathematical model to find the number of VoWiFi users possible within a WLAN Access Point (AP) considering G.729 vocoder. Arbitration inter-frame space (AIFS) has been utilized in our study to evaluate the channel state prior to transmitting real-time data between user equipment (UE) devices. Additionally, short inter-frame spacing (SIFS) has been employed to transmit Request To Send (RTS)/Clear To Send (CTS) and Acknowledgement (ACK) frames, enabling an examination of the VoWiFi cell capacity. Again, to increase the VoWiFi cell capacity, we incorporated the compressed RTP (cRTP) protocol. Further, we conducted an analysis on the impact of retransmission on VoWiFi cell capacity. This analysis involved a comparison of the results using VBR traffic with the previous WLAN standards, namely IEEE 802.11b/g/n/ac/ax. We observed that the improvement in VoWiFi cell capacity in VBR traffic is approximately 2.6 times more than the CBR traffic. Further, our research revealed that the enhancement in VoWiFi cell capacity is approximately 1.5% higher when utilizing AIFS compared to Distributed Coordination Function (DCF) inter-frame spacing (DIFS).