Spectrum sensing over frequency-selective fading channel with tap and spatial correlations

Reliable spectrum sensing should be able to operate under realistic wireless environments such as multipath and fading. Based on the optimal spectrum sensing with multiple receiver antennas over multipath channels, this paper presents further studies into two more practical detection methods, the modified energy detection (MED) and the equal gain detection (EGD), over frequency-selective fading channels, with focus on the impact of multipath tap correlation on the sensing performance. Both simulation and analytical results are provided. It is verified that utilizing multipath propagation enhances the detection probability of the EGD, which approaches that of the optimal detection. The EGD also demonstrates better performance than the MED and the conventional generalized likelihood ratio test. The tap correlation can have either constructive or destructive effect to the spectrum sensing system depending on how well the tap correlation matches the source signal´s temporal correlation, whereas the spatial correlation always degrades the detection performance.