Overcoming sensing failure problem in double threshold based cooperative spectrum sensing

Energy detection is widely used spectrum sensing algorithm in cognitive radio networks because of the reason it is simple and easy to implement and does not require the prior information about the Primary user (PU). However, performance of conventional energy detector falls in low signal to noise ratio (SNR) region. Cooperative spectrum sensing (CSS) in which each Cognitive radio (CR) employs double threshold was introduced to increase the reliability of decision especially in low SNR region but suffers from sensing failure problem. In this paper, we are proposing a method for overcoming sensing failure problem in double threshold CSS. In this method, each CR either sends one bit decision when observed energy lies out of the confused region or sends two bit decision based on quantization when energy lies within the confused region. Final decision about the presence or absence is taken at fusion center after processing the received decisions. We have carried out MATLAB simulations to prove the superiority of the algorithm in achieving a tradeoff between traffic overhead and detection performance.