Comparisons of Error Control Techniques for Wireless Video Multicasting

Packet loss rates in wireless local area networks (WLANs) are highly dynamic and location dependent. Therefore, multicasting of compressed video streams over such networks requires significantly different error control approaches from those used over wired networks. This paper explores three different methods employed separately and in combination, to improve the quality of video delivery on WLANs. The approaches are: leader-driven multicast (LDM), the monitoring of MAC layer unicast (re)transmissions by other receivers; application-level forward error correction (FEC) using block erasure codes; and negative feedback from selected receivers in the form of extra parity requests (EPR) in order to correct losses. The performance of these three methods is evaluated using both experimentation on a mobile computing testbed and simulation. The results indicate that, while LDM is helpful in improving the raw packet reception rate, the combination of FEC and EPR is most effective in improving the frame delivery rate.