Towards Battery-Free Wireless Sensing via Radio-Frequency Energy Harvesting

TL;DR

REHSense is an innovative RF energy harvesting-based wireless sensing system that significantly reduces power consumption while maintaining high sensing accuracy for applications like activity and gesture recognition.

Contribution

The paper introduces REHSense, a novel RF energy harvesting approach that enables battery-free wireless sensing using commercial hardware, reducing energy use by over 98%.

Findings

Achieves comparable sensing accuracy to Wi-Fi-based solutions.

Reduces power consumption by 98.7%.

Harvests up to 4.5mW of RF energy.

Abstract

Diverse Wi-Fi-based wireless applications have been proposed, ranging from daily activity recognition to vital sign monitoring. Despite their remarkable sensing accuracy, the high energy consumption and the requirement for customized hardware modification hinder the wide deployment of the existing sensing solutions. In this paper, we propose REHSense, an energy-efficient wireless sensing solution based on Radio-Frequency (RF) energy harvesting. Instead of relying on a power-hungry Wi-Fi receiver, REHSense leverages an RF energy harvester as the sensor and utilizes the voltage signals harvested from the ambient Wi-Fi signals to enable simultaneous context sensing and energy harvesting. We design and implement REHSense using a commercial-off-the-shelf (COTS) RF energy harvester. Extensive evaluation of three fine-grained wireless sensing tasks (i.e., respiration monitoring, human activity, and hand gesture recognition) shows that REHSense can achieve comparable sensing accuracy with conventional Wi-Fi-based solutions while adapting to different sensing environments, reducing the power consumption by 98.7% and harvesting up to 4.5mW of power from RF energy.