Utility-Based H.264/SVC Video Streaming Over Multi-Channel Cognitive Radio Networks

摘要

In a cognitive radio (CR) network, a secondary user (SU) with multiple interfaces is capable of accessing multiple CR channels in an opportunistic fashion. Therefore, the available channel resources may change dramatically, and the reliabilities of the multiple accessed CR channels are also time-varying. Video streaming in such a multi-channel CR network faces great challenges in guaranteeing the quality of the received video. To deal with these challenges, we adopt H.264/SVC encoded video as the source and firstly optimize the video streaming from the perspective of exploiting more channel resources for the SU by developing a flexible sensing-transmission scheme for opportunistic spectrum access (OSA). In this scheme, the primary user activity, channel sensing result, and channel sensing accuracy are all considered in reducing the unnecessary channel sensings and correspondingly extending the transmission duration for the SU. Based on the flexible sensing-transmission scheme, we then propose a utility-based H.264/SVC video transmission scheme to further improve the expected video quality at the receiver. Specifically , the network abstraction layer units (NALUs) in the SVC video are assigned utilities which accurately reflect their contributions to the video quality, and the total effective utility of expected received video is maximized through perfectly dispatching the NALUs over the multiple CR channels. Both analytical studies and experimental results validate the effectiveness and efficiency of the proposed method.