Effect of Packet Retransmission on VoWiFi Cell Capacity Using IEEE 802.11ac for VBR Traffic

Abstract

The demand for Wireless Fidelity (WiFi) is increasing tremendously. Due to a lack of cellular signal strength, ongoing cellular calls may suffer a degradation in Quality-of-Service (QoS) or become disconnected from the cell tower. Voice over WiFi (VoWiFi) is the best alternative in this scenario, because it provides users with the same benefits as they receive from the cellular tower. In our study, we have considered the VoWiFi as Voice over Internet Protocol (VoIP) over WiFi. To prevent the bandwidth wastage due to background noise, we have incorporated silence suppression for Variable Bit Rate (VBR) traffic. As a result, the capacity of VoWiFi cell can be increased relative to the Constant Bit Rate (CBR) traffic. Additionally, we used Arbitration Inter-frame Spacing (AIFS) and Compressed RTP (cRTP) to increase the VoWiFi cell capacity of IEEE 802.11ac (i.e. fifth generation Wireless Local Area Network (WLAN) standard) Access Point (AP). We used the DCF Interframe Spacing (DIFS) and AIFS to compare the results of CBR and VBR traffics. Furthermore, we applied the retransmission mechanism to avoid VoWiFi voice packet loss and compared the results using DIFS and AIFS to determine their effectiveness.