cRTP performance over IEEE 802.11 for VoIP applications
Kevin Ko · Summit (Simon Fraser University) · 2004
The deployment of IEEE 802.11 WLAN networks and Voice-over-IP (VoIP) systems in offices and homes has surged in recent years, and will likely continue its growth. Due to its wireless nature, 802.11 networks still trail its wired equivalents in bandwidth and transmission rates. On the other hand, Voice-over-IP and other real-time applications are very capable of consuming bandwidth and overwhelming networks that are unable to handle their rapid-succession traffic streams. The wireless network bandwidth limitations therefore set the stage as a bottleneck, and can greatly impact the perceived quality of VoIP connections. In this report, the effectiveness of RTP header compression (cRTP) and silence suppression (SS) applied to typical Voice-over-IP traffic over 802.11 wireless networks is investigated through integrated simulations. Both IEEE 802.11 distributed coordination function (DCF) and point coordination function (PCF) networks are examined, with results showing that PCF distributed systems are more suitable toward real-time traffic such as VoIP. The reduction in packet count and packet sizes result in better perceived connection quality through shorter end-to-end delays and reduced packet loss. Correspondingly, the witnessed improvements also allow more users to be accommodated in a particular network before reaching the same quality-affecting threshold.