Delivering live-action to handheld devices: Experimental results and recommendations

This paper addresses the multicast capabilities of WiFi systems transmitting to handheld devices in outdoor public spaces. The analysis includes a comparison of access point antennas in terms of received signal strength for different conditions and handset orientations. An H.264 AVC encoder and IP packetisation unit is used to multicast IP video streams to WiFi enabled mobile clients. Measurement and simulation results show that body shadowing and handset orientation seriously degrade the video quality. Dual polarized AP antennas are shown to enhance operating range and video performance. A shadowing and depolarization margin of 22dB is required to ensure high quality multicast reception at the mobile handsets.