Optimal Packet Scheduling for Multi-Description Multi-Path Video Streaming Over Wireless Networks
As developments in wireless networks continue, there is an increasing expectation with regard to supporting high- quality real-time video streaming service in such networks. The recent advances in multi-description (MD) multi-path transport has made it a promising technology for content-rich wireless multimedia communications. This paper presents a rate-distortion (R-D) optimized packet scheduling algorithm (OPT- MD) for streaming MD-coded video along multiple wireless paths. Our algorithm relies on R-D hint information that is used to characterize a packet in a R-D sense. The information consists of the size of the packet in bits and the importance of the packet for reconstructing the video. Each of the video description adaptively selects certain important packets for transmission according to the quality of the transmission path by simultaneously considering bandwidth, bit error rate, and delay so that the overall end-to-end video distortion in terms of the mean square error (MSE) is minimized. Extensive simulation results demonstrate that OPT-MD can improve the quality of video streaming significantly as compared to a conventional scheduling approach that does not consider the relative importance of the video packets and the channel conditions (RANDOM-MD). The gains in performance reach up to 5 dB and 4 dB for streaming MD-coded format QCIF FORMAN and TABLE video sequences, respectively, in the scenario of adaptation to a simulated time- varying network channel. Our efforts in this work provides an important methodology for high-quality real-time video streaming applications over wireless networks.