CR Based Video Communication Testbed with Robust Spectrum Sensing / Handoff

Abstract

As radio spectrum is becoming congested, wireless communications require more efficient spectrum usage. Recently, the cognitive radio (CR) techniques have become attractive as they can utilize any unused spectrum. In this paper, we build a CR video communication test-bed, which implements spectrum sensing and spectrum handoff functionalities in USRP boards. We have implemented compressive spectrum sensing, intelligent spectrum handoff, multi-video-flow transmission, under TDMA scheduling and Raptor codes for reliable video transmissions. By using compressive sensing in spectrum sensing method, the spectrum detection accuracy is improved without much algorithm complexity, and it is also robust to the noise uncertainty due to the use of cyclostationary features. To realize intelligent spectrum handoff, we have designed a real-time jamming detection scheme, as well as synchronized spectrum switching method. We have also implemented a multi-point TDMA-based communication system, which enables any node to send out multiple video flows to different neighbors with pipelined and scheduled data transmissions. We also proposed a special rateless codes called prioritized Raptor codes for more reliable video transmission and implemented in the GNU Radio applications. The proposed CR video transmission testbed can be used for new protocol testing purpose.