How to Perform Distributed Precoding to Wirelessly Power Shelf Labels: Signal Processing and Measurements

TL;DR

This paper explores distributed MIMO-based wireless power transfer for shelf labels, optimizing precoding to improve energy delivery efficiency while validating results through experiments with an 84-antenna testbed.

Contribution

It introduces a method for optimizing precoding weights in distributed MIMO WPT systems, considering both synchronized and unsynchronized configurations, with experimental validation.

Findings

Increasing antennas improves energy transfer efficiency.

Coherent systems outperform non-coherent systems.

Experimental results confirm simulation trends.

Abstract

Wireless power transfer (WPT) has garnered increasing attention due to its potential to eliminate device-side batteries. With the advent of (distributed) multiple-input multiple-output (MIMO), radio frequency (RF) WPT has become feasible over extended distances. This study focuses on optimizing the energy delivery to Energy Receivers (ERs) while minimizing system total transmit power. Rather than continuous power delivery, we optimize the precoding weights within specified time slots to meet the energy requirements of the ERs. Both unsynchronized (non-coherent) and synchronized (coherent) systems are evaluated. Our analysis indicates that augmenting the number of antennas and transitioning from an unsynchronized to asynchronized full phase-coherent system substantially enhances system performance. This optimization ensures precise energy delivery, reducing overshoots and overall energy consumption. Experimental validation was conducted using a testbed with84 antennas, validating the trends observed in our numerical simulations.