Optimal threshold of energy detection for spectrum sensing in cognitive radio

Cognitive radio is regarded as a candidate technology to solve the problem of low efficiency in spectrum utilization. The first step for the opportunistic use of frequency bands is spectrum sensing. In this paper, we focus on the energy detection for spectrum sensing. We get the Closed-form expression to the optimal threshold of local detection to get a trade-off between missed detection probability and false alarm probability. Next, we show the threshold can be adjusted to different scenarios as needed. Finally, as the same trade-off, the optimal threshold of cooperative sensing with the half-voting fusion rule is discussed by numerical result.