Multicast video streaming over WiFi networks: Impact of multipath fading and interference

Delivery of multimedia digital content through wireless networks poses non-trivial performance issues because of scarcity and volatility of the wireless medium. The goal of this study is to analyze the impact of multipath fading and interference on multicast video streaming in an indoor LOS (Line of Sight) wireless environment using off-the-shelf fixed WiFi equipment. Multipath fading experienced by the receivers is represented by empirically estimating ricean K-factor from packet traces captured at the receivers. Degradation in the video quality incurred during transmission is quantified by measuring video quality metric (VQM). To quantify the impact of channel interference, controlled traffic is generated on a channel adjacent to the selected channel. We use human movements to alter the depth of signal fading at the receivers. Our experiments show that packet loss increased two times in the face of multipath fading and almost three times in the face of channel interference. The measurements presented in this paper can help users to monitor and maintain the quality of their wireless networks and optimize the use of limited network resources.