Node Placement Optimization in Wireless Powered Communication Networks

In this paper, we study the optimal node placement problem in wireless powered communication networks (WPCNs), where the wireless devices (WDs) harvest the radio frequency energy transferred by dedicated energy nodes (ENs) in the downlink, and use the harvested energy to transmit data to information access points (APs) in the uplink. In particular, we are interested in minimizing the deployment cost on ENs and APs, while satisfying the energy harvesting and communication performance requirements of the WDs. Specifically, we first study the optimal placement of ENs given fixed AP locations, where an efficient greedy algorithm is proposed to tackle the non-convexity of the problem. Based on the obtained results, we further propose an alternating optimization method that jointly optimizes the placements of ENs and APs. Simulation results show that the proposed methods can effectively reduce the network deployment cost to guarantee the given performance requirements, which is a key consideration in the future applications of WPCNs.