Blind Sensing Algorithms for Cognitive Radio

In this paper, simulation results are provided for a novel blind sensing algorithm. The results are compared with that of an energy detector. Since it is difficult to estimate the noise variance accurately, the performance of the energy detector with about 1 to 2 dB uncertainty in noise variance is considered. Simulations show the algorithm to perform much better than the energy detector. The algorithm does not require an estimate of the noise power. Till date, not much work has been done on blind sensing algorithms in the low SNR regime. Algorithms based on cyclo-stationarity have been developed in previous papers. However, the performance of these algorithms at low SNR (like -10 dB) has not been investigated. Moreover, unlike the previous algorithms, the novel sensing algorithm here does not require information about the multipath channel distortions the primary signal has undergone on its way to reaching the secondary user. This blind sensing is particularly useful, if the secondary user does not have much information about the primary user (say wireless microphone user)