Optimal sensing duration and threshold selection approach in cognitive radio networks with cooperative spectrum sensing

Perfect detection of unused/underutilized frequency band of the primary user (PU) in the cognitive radio communication systems is an essential component for its efficient utilization by the secondary/cognitive user (CU) without any interference. In the cooperative spectrum sensing scenario, the presence or absence of PU is determined by analyzing the decisions of each CU engaged in the collaboration. In this paper, we have emphasized on the significance of spectrum sensing duration in the optimal threshold selection approach in the cooperative spectrum sensing scenarios for a range of the received PU signal signal-to-noise ratio (SNR) from low to high values. The sensing duration parameter is taken as t_s = 2.5 ms in the higher SNR environment, whereas in the lower SNR environment when the optimal threshold condition fails, t_s is kept dynamic to satisfy minimum target values of sensing performance parameters. We have computed the spectrum sensing performance parameters and throughput using the same approach and compared the results with those obtained from the constant false-alarm rate (CFAR), constant detection rate (CDR), and minimized error probability (MEP) threshold selection approaches. The spectrum sensing performance computed by the proposed approach is significantly improved as compared with the other reported approaches. At SNR = −24 dB, global probability of false alarm Q_f = 0.002 and global probability of detection Q_d = 0.999 are achieved. However, the throughput is relatively less for low SNR values.