A System Architecture for Battery-free IoT Networks

While much research effort has been invested in long-range and low-power uplink communication for battery free IoT networks, current deployments lack a scalable bi-directional communication infrastructure for data collection and processing with battery-free devices. To fill this gap, we introduce LoW-Fi, a system architecture specifically designed to meet the requirements of battery-free IoT applications. We show the suitability of LoW-Fi for deploying monitoring systems for precision agriculture indoors. This sector is revolutionizing with the installation of smart greenhouses that require the constant monitoring of ambient parameters to ensure optimal conditions for the crops growth. Our system is implemented using commercial off-the-shelf devices, and it works at the intersection of WiFi and LiFi for downlink and RF backscatter for uplink, retaining the advantages of each technology and solving their practical limitations. We evaluate LoW-Fi performance in a real greenhouse, and the experimental results show that it can achieve an uplink (downlink) range of 45 m (70 m) with 0% BER. The aggregated data rate is up to 4.5 Mb/s.