Channel state dependent adaptive spatial spectrum sensing algorithm for cognitive radios

Energy Detection (ED) is a well known approach for spectrum sensing due to its simplicity, low computational cost and its validity for all signal formats. However, it is ineffective under low signal to noise ratio conditions. On the other hand, the recent convergence of almost all the wireless standards to the incorporation of spatial dimension in these wireless systems has made spatial spectrum sensing based on Peak to Average Power Ratio (PAPR) of the received signal, a promising approach. Though it works well under all channel conditions but the related cost is high computational complexity of the algorithm. With the motivation of improving the sensing ability of cognitive radio under all channel conditions combined with the existing hardware constraints of low computational complexity, we have proposed an amalgamation of the aforementioned schemes (ED and PAPR based spatial spectrum sensing) with an element of adaptation by switching between these two techniques depending upon channel states. Proposed adaptive scheme is compared with ED and PAPR based spatial spectrum sensing on the basis of probability of detection, probability of false alarm and complexity.