A Novel Triggered Asynchronous Spectrum Sensing Scheme in Cognitive Radio Networks

To improve the performance of spectrum sensing, cooperation among Cognitive Radios (CRs) has been proposed recently as an effective solution. A great part of the existing spectrum sensing algorithms adopt synchronous spectrum sensing method, while the rest asynchronous spectrum sensing algorithms have a severe demand for terminals´ sensing performance. This paper proposes a novel Triggered Asynchronous Spectrum Sensing (TASS) scheme , which loosens the demand for sensing terminals´ performance (i.e. local sensing algorithm, detection time, observation time length and sensing period). Not only presents the advantage of great instantaneity in asynchronous sensing, the algorithm also reduces calculation in fusion center by deploying the altered-result triggered nature and the Period Hierarchy Management (PHM) system. Since the proposed scheme considers the occupancy of the licensed band in sensing data fusion, the advantage of sensing accuracy will be more distinct when the idle and the busy time length of licensed band is not equal. With the simulation comparison of several typical asynchronous sensing methods, the scheme in this paper shows an excellent performance.