Abstract :
The increase in the bandwidth of wireless channels and the computing power of mobile devices increase the interest in video communications over wireless networks. However, the high error rate and the rapidly changing quality of the radio channels can be devastating for the transport of compressed video. In motion compensated coding, errors due packet losses are propagated from reference frames to dependant frames causing lasting and annoying visual effects. In addition, the bounded playout delay for interactive video limits the effectiveness of retransmission-based error control. In this paper, we propose extending retransmission-based error control to provide different levels of protection to packets according to their importance to the reconstructed video quality. This type of prioritization is achieved through redundant retransmission on diverse paths. In addition, as path failures, which are common in mobile wireless networks, can hurt the interactivity of the video session, our mechanism monitors the available paths and switches between them seamJessly. We evaluated the effectiveness of the mechanism under different network conditions. Simulation results show that the mechanism is able to maintain the video quality under different loss rates, and with less overhead compared to other error control techniques, such as reference frame updates.
