An Efficient Multiple Lags Selection Method for Cyclostationary Feature Based Spectrum-Sensing

The principle of cognitive radio (CR) systems is to utilize the licensed spectrum when their interference to primary users (PUs) can be maintained below a certain threshold. Thus, to successfully coexist, cognitive users must have awareness of PUs presence in the vicinity. As most communication signals exhibit statistical periodicities, cyclostationary feature detection (CFD) can be used to perform the task of sensing the spectrum for PUs presence. A second-order statistical approach is most widely used to perform CFD in which a set of lags should be chosen for statistical testing. The optimal method for choosing multiple lags requires knowledge of the 4th-order cyclic cumulant of PUs' signals, which can be a burden in practice. In this letter, we present a new idea for lag set selection with which avoids the mentioned 4th-order cumulant burden. The results, verified via analysis and simulation, show that the performance of the proposed method is comparable to the optimal one in the low signal to-noise ratio region where it is most critical for CR applications.