Optimal threshold for dual-stage spectrum sensing in cognitive radio

Cognitive radio (CR) is a typical technology to allow secondary users use the licensed spectrum resource dynamically. Spectrum sensing is one of the important technics in CR. In this paper, optimal threshold for dual-stage spectrum sensing is researched. Two-threshold energy detection (ED) and one-threshold cyclostationary feature detection (CFD) are chosen as the coarse sensing technique and the fine sensing technique respectively. Given the characteristics of the two sensing techniques, optimal thresholds of dual-stage spectrum sensing are deduced based on Sequential Unconstrained Minimization Technique. Both sensing speed and accuracy are considered at the same time to get the optimal sensing performance. The simulation results show that the optimal thresholds improve the performance of spectrum sensing compared with the existing representative dual-stage sensing scheme.