Resource Allocation Algorithm for UAV Aided Symbiotic Radio Communication System

Aiming at the issue of how to improve the system transmission rate in a multiple Internet of things (IoT) device application scenario, we propose the resource allocation algorithm of the symbiotic radio communication system under multiple backscatter devices (BDs) assisted by unmanned aerial vehicle (UAV). We formulate the optimization problem of maximizing BDs’ sum rate by jointly optimizing the time allocation, BDs’ reflection coefficient and UAV location under constraints of BD’s harvested energy, quality of service (QoS) of cellular user and UAV. Since the problem is non-convex, it is difficult to solve directly. Therefore, the iterative algorithm based on block coordinate descent (BCD) method can be adopted, which decomposes the optimization problem into three sub-problems: time allocation, reflection coefficients of BDs and UAV location. For non-convex sub-problems, we utilize the successive convex approximation (SCA) technique to transform it into convex optimization problems, and we prove that the conversion is convex optimization problems. Simulation results show that our proposed algorithm converges fast, and significantly improves the system transmission rate compared with other schemes.