Distributed Energy Cooperation for Multicell Wireless Powered Communication Networks with Imperfect Energy Storage Efficiency

Abstract

This paper investigates the energy cooperation for multicell wireless powered communication networks with imperfect energy storage efficiency in a distributed manner. In the considered network, access points (APs) are all powered by renewable energy and charged to associated users via wireless energy transfer in the downlinks. Moreover, the energy cooper-ation scheme enables each AP to share energy with neighboring APs, allowing all users to obtain sustainable energy for wireless information transfer in the uplinks. To avoid the dissipation of unused energy, each AP is equipped with a battery, in which the unused energy can be stored in its battery for subsequent communication. In this practical scenario, energy efficiency is maximized through optimizing energy allocation. Considering that the battery status is constrained by energy causality in the time dimension, the joint analysis based on multiple time intervals is a huge challenge for problem modeling and solving. To this end, a nonconvex problem is formulated to maximize the long-term energy efficiency of the entire network. By using nonlinear fractional programming, the original problem is transformed into a convex form. Then, a distributed iterative algorithm based on the partial Lagrange dual decomposition is proposed to alleviate the dependence on the central controller. Finally, a simulation example is presented to validate the main results.