Refined Nonlinear Rectenna Modeling and Optimal Waveform Design for Multi-User Multi-Antenna Wireless Power Transfer

TL;DR

This paper develops a refined nonlinear rectenna model and proposes optimal waveform design algorithms for multi-user wireless power transfer, significantly improving harvested power efficiency in multi-antenna systems.

Contribution

It introduces a new nonlinear rectenna model and develops algorithms for optimal waveform design in multi-user wireless power transfer systems.

Findings

Proposed waveform designs outperform existing schemes in simulations.

New rectenna model accurately predicts harvested power.

Algorithms efficiently solve non-convex optimization problems.

Abstract

In this paper, we study the optimal waveform design for wireless power transfer (WPT) from a multi-antenna energy transmitter (ET) to multiple single-antenna energy receivers (ERs) simultaneously in multi-path frequency-selective channels. First, we propose a refined nonlinear current-voltage model of the diode in the ER rectifier, and accordingly derive new expressions for the output direct current (DC) voltage and corresponding harvested power at the ER. Leveraging this new rectenna model, we first consider the single-ER case and study the multisine-based power waveform design based on the wireless channel to maximize the harvested power at the ER. We propose two efficient algorithms for finding high-quality suboptimal solutions to this non-convex optimization problem. Next, we extend our formulated waveform design problem to the general multi-ER case for maximizing the weighted sum of the harvested powers by all ERs, and propose an efficient difference-of-convex functions programming (DCP)-based algorithm for solving this problem. Finally, we demonstrate the superior performance of our proposed waveform designs based on the new rectenna model over existing schemes/models via simulations.