A Fast Two Stage Detector for Spectrum Sensing in Cognitive Radios

Spectrum sensing techniques for Cognitive radios have led to the emergence of a wide variety of analytical methods to detect the presence of a primary user. Though each technique has its own advantages, the disadvantages associated with them makes a standalone implementation of the technique unviable for practical use. A two stage detector for spectrum sensing can be used to mitigate the disadvantages of a single stage detection technique and synergize the advantages offered by the individual methods. However, a two stage analysis increases the time taken to sense the spectrum and arrive at a conclusive result. In this paper, we propose an algorithm which can be used to minimize the time taken by a two stage detector. Simulation results have been used to show that the proposed algorithm leads to a large savings in time as compared to an existing two stage detection algorithm. The savings in time increases as spectrum utilization of the band under consideration becomes more sparse.