Energy Efficiency Maximization for UAV-Assisted Cognitive Radio System

In the cognitive internet of things network, achieving high energy efficiency is a development trend in unmanned aerial vehicle (UAV)-assisted communication systems. In this paper, we consider a UAV-assisted cognitive radio (CR) system, where UAV transmits the collected data to the base station (BS) by reusing the spectrum of the primary transmitter (PT). Our objective is to maximize the energy efficiency under interference constraint, by optimizing spectrum sensing duration, spectrum sensing threshold, and UAV horizontal position. To solve the optimization problem, an alternate iteration framework is proposed to iteratively solve the three decoupled sub-problems. The simulation results demonstrate the accuracy of the theoretical analysis, as well as the effectiveness and convergence of the proposed algorithm.