Joint Optimal Multipath Routing and Rate Control for Multidescription Coded Video Streaming in Ad Hoc Networks
This paper studies an important problem, namely, the joint multipath routing and rate control for multidescription coded (MD-coded) video streaming in wireless ad hoc networks. In addition to selecting a pair of paths to optimize the expected end-to-end video quality, we also explore an optimal packet skipping strategy for the rate control in order to minimize the impact of the skipped packets on the quality of the video. The R-D hint information, consisting of the size of the packets in bits and the importance of the packets for reconstructing the video, is used to characterize the packets in an R-D sense. Since searching for paths to minimize the expected end-to-end video distortion by simultaneously considering the skipped packets prior to the transmission and those dropped/delayed during the transmission is a highly complex problem and is expected to be NP-hard, we develop a heuristic greedy-relaxation-based routing solution that enables the system to efficiently select near-optimal paths. Extensive simulation studies have been conducted to compare the performance of the proposed algorithm with that of several existing algorithms, showing the superior performance of the proposed one. Such a joint rate control and multipath routing approach provides an important methodology for high-quality real-time video streaming applications over ad hoc wireless networks.