Energy-efficient communication for UAV-enabled mobile relay networks

Abstract

Relaying that can be classified as fixed or mobile is an effective technique to improve the throughput and reliability and also to extend the coverage in wireless networks. Compared with the conventional fixed relaying, mobile relaying has attracted great interest recently, because of the the rapid development of unmanned aerial vehicles (UAVs) having high mobility, low cost and deployment flexibility properties. Thus, in this study, mobile relaying technique in which the relay nodes are mounted on the fixed wing UAVs is considered. Due to the increasing energy consumption costs, environmental reasons, low lifetime of the mobile devices and limited on-board energy of the UAVs, energy-efficient communication is an important topic for the future wireless network design. Therefore, energy-efficient communication is examined for the UAV-enabled Decode-and-Forward (DF) mobile relay networks in this paper. Energy-efficiency (EE) maximization problem is formulated as the ratio of the total data rate to the total energy consumption by considering the quality of service (QoS) requirements of the users. As the formulated problem is mixed integer non-convex, it is hard to solve in this form. Thus, we decompose it into two subproblems as user-scheduling and power allocation and propose to solve each subproblem separately to overcome the complexity of the problem. The efficiency of the proposed algorithm is shown by performing extensive simulations for various system parameters.