Novel study on Cooperative Spectrum Sensing for Cognitive Radio

In cognitive networks, cooperative spectrum sensing is employed to detect the presence of primary user quickly. In this paper, we study the improvement in sensing performance of a cognitive user U₁ by allowing another cognitive user U₂ to act as its relay. We derive the expression of SNR, and exploit the improvement in SNR to explain why the sensing performance may be improved by using cooperation. For the situation where there is power constraint for U₂ when acting as a relay, we pay more attention to studying which parameter affects the sensing performance significantly. We first develop a new numerical model for sensing performance analysis, then we address that, the product of transmission power of cognitive radio and channel gain (between cognitive users) is tightly related to the value of SNR. Further, we propose an important parameter beta that can be predetermined in a practical cognitive network, and show that beta impact the sensing performance greatly.