Leveraging Deliberately Generated Interferences for Multi-sensor Wireless RF Power Transmission

TL;DR

This paper introduces DRAMA, a novel method that deliberately creates random interferences in multi-sensor RF power transmission to improve energy harvesting efficiency, demonstrated through real-world experiments.

Contribution

The paper proposes a new duty-cycled random-phase multiple access scheme that leverages deliberate interference to enhance RF energy transfer efficiency.

Findings

DRAMA reduces RF power input by up to 70% for sensor recharging.

The approach improves power conversion efficiency and energy harvesting.

Real-testbed experiments validate the advantages over existing methods.

Abstract

Wireless RF power transmission promises battery-less, resilient, and perpetual wireless sensor networks. Through the action of controllable Energy Transmitters (ETs) that operate at-a-distance, the sensors can be re-charged by harvesting the radiated RF energy. However, both the charging rate and effective charging range of the ETs are limited, and thus multiple ETs are required to cover large areas. While this action increases the amount of wireless energy injected into the network, there are certain areas where the RF energy combines destructively. To address this problem, we propose a duty-cycled random-phase multiple access (DRAMA). Non-intuitively, our approach relies on deliberately generating random interferences, both destructive and constructive, at the destination nodes. We demonstrate that DRAMA optimizes the power conversion efficiency, and the total amount of energy harvested. Through real-testbed experiments, we prove that our proposed scheme provides significant advantages over the current state of the art in our considered scenario, as it requires up to 70\% less input RF power to recharge the energy buffer of the sensor in the same time.