Enhanced energy detector using adaptive wiener filter in cognitive radio

Abstract

The rising demand in wireless services and applications bring channel constraint on the existing frequency spectrum allocation scheme. By addressing the concept of cognitive radio technique (CR), it is possible to mitigate the scarcity of spectrum channel and underutilization of spectrum efficiencies. Various techniques and methods have been used to maximize the probability of detection (Pd) in CR system. Energy detector spectrum sensing is one of the transmitter based techniques, which detects the presence of primary user in cognitive system. However performance indicator metrics show that the energy detector algorithm has poor performance when the received SNR value is too low as compared to the system threshold value. In this paper the performance of conventional and enhanced energy detector (using adaptive Wiener filter) is examined based on Receiver Operating Curve (ROC) and Complementary Receiver Operating (CROC). Simulation results are plotted for different threshold values, false alarm probability, detection probability and the received SNR. Results for AWGN and Rayleigh flat fading channel models are presented. The Simulations results in Rayleigh flat fading channel show that, the insertion of adaptive Wiener filter in conventional energy detector has improved the probability of detection by 8% and reduce the probability of miss detection by same amount.

Keywords: adaptive Wiener filter, Cognitive radio, energy detector, false alarm and detection, performance metrics (ROC, CROC), probability spectrum sensing, threshold value