Energy detection threshold optimization for cooperative spectrum sensing

Cognitive radio has been recognized as one of the most promising technologies dealing with the scarcity of the radio spectrum. In cognitive radio system, with spectrum sensing, secondary users are allowed to utilize the frequency bands of primary users when the bands are idle. Hence, how to accurately detect the idle frequency bands has attracted many researchers´ eyes. Energy detection is the common method for idle band detection. However, the improper energy detection threshold setting can dramatically affect the performance of the cognitive radio system. There are two types of errors in spectrum sensing: false alarm and miss-detection. The lower probability of false alarm means more underutilized spectrum can be reused by secondary users and the lower probability of miss-detection, the better primary users are protected. In this paper, we propose a fast and accurate search method for optimal local energy detection threshold, which can minimize the total errors in spectrum sensing. Simulation results show that our estimated optimal energy threshold is consistent with the actual one.