Hierarchical-matching based scalable video streaming over multi-channel cognitive radio networks

With its ability to promote the wireless spectrum utilization, cognitive radio (CR) is a promising technology for various broadband wireless video applications. A secondary user (SU) with multiple wireless interfaces is capable to sense and access multiple CR channels, each of which can only be accessed in an opportunistic fashion. Therefore, the amount of available channel resources may change dramatically, and the reliabilities of the multiple accessed CR channels are time-varying and different from each other. To improve the quality of the received video in such a multi-channel CR network, we first develop a flexible sensing-transmission structure for dynamic spectrum access according to primary user activity and channel sensing accuracy. Based on the proposed sensing-transmission structure, we then propose a hierarchical-matching scheme to adapt the scalable video stream to the multiple time-varying and reliability-different CR channels, where we consider the priorities and validity of the network abstraction layer units (NALUs) in the transmission scheduling. Under this scheme, the more important NALUs at the global Group Of Pictures (GOP) scope will be dispatched over the more reliable channels. Both analytical studies and experimental results show the effectiveness and efficiency of the proposed method.