Cooperative Adaptive Threshold Based Energy and Matched Filter Detector in Cognitive Radio Networks

CR (cognitive radio) is the key technology for unlicensed SUs (secondary users) to exploit the unused spectrum of PUs (primary users) via opportunistic spectrum access. In this paper, we propose a new spectrum sensing method using cooperative adaptive threshold based on energy and matched filter detector in cognitive radio networks. The ED (energy detector) is highly susceptible to noise uncertainty condition. Also, ED cannot well differentiate between the signal and noise, if the detected observational value of the PU lies in the confused region i.e., between signal and noise. We propose a scheme based on cooperative adaptive threshold that uses MF (matched filter) detector as a second stage detector for the reliable detection in the confused region and energy efficient ED as first stage detector for the clear region where the detector can easily differentiate between signal and noise and makes its own local decision. The fusion center collects the local decisions and observational values of the secondary users and then makes the final decision to ascertain whether the primary user is present or not. Simulation results shows that our proposed method has higher detection performance as compared to other spectrum sensing methods.