An Energy Harvesting Chain Model for Wireless-Powered IoT Networks

Internet of Things (IoT) is an emerging technology that will change our daily life. However, due to the size limitation, most of them cannot be equipped with a large battery to support the long serving time requirement. Thus, the energy harvesting (EH) technology, which can wirelessly provide energy for battery-constrained devices, has become a promising solution for IoT. In this paper, we propose an energy harvesting chain model for a wireless-powered IoT network with one information access point (AP), one radio frequency (RF) energy source and a set of IoT devices. The energy is transferred from the RF source to the first user, and the subsequent user harvests energy from the previous one while it transmits information to the AP. In this paper, we study two problems under the proposed energy harvesting chain model, which are total-time minimization (TTM) and sum-throughput maximization (STM). By applying convex optimization techniques, both problems can be solved in closed-form. Then, a suboptimal time allocation scheme is studied. It is shown by simulation results that the proposed chain model is useful and can be applied to specific practical application scenarios.