Contents I. Introduction
One of the typical application scenarios for a CSN is to monitor the spectrum usage state of wireless devices at a specific time and/or in a specific area. In order to improve spectral efficiency, CSs are permitted to access the idle licensed frequency bands without causing any harmful interference to primary users (PUs). Because of a deep fading and shadowing effects, collaborative spectrum sensing is often used to enhance sensing performance at cost of increased overhead traffic, energy consumption, and computational complexity. Energy efficiency [1], which is defined as the average throughput per Joule of energy, is an important metric to measure the network performance. Research on the collaborative spectrum sensing under energy constrained have become important topics for future wireless communication networks. Some recent works studies [2]–[9] have focused on optimizing the sensing parameters for achieving the better sensing performance. Sensing duration, transmission power, detection threshold, and the number of CSs are very important parameters to consider when designing a scheme for energy-constrained CSN.
