Utility-Based Time and Power Allocation on an Energy Harvesting Downlink: the Optimal Solution

Abstract

In this paper, we consider the allocation of power level and time slots in a frame to multiple users, on an energy harvesting broadcast system. We focus on the offline problem where the transmitter is aware of the energy arrival statistics of a frame before the frame starts. The goal is to optimize throughput in a proportionally fair way, taking into account the inherent differences of channel quality among users. Analysis of structural characteristics of the problem reveals the biconvex nature of the problem. Due to biconvexity, a Block Coordinate Descent (BCD) based optimization algorithm that converges to one of the multiple optima is proposed. Simulation results show that the resulting allocation achieves a good balance between total throughput and fairness. © 2013 Springer-Verlag London.