Energy networking in Light-based IoT: Design, implementation, and experimental validation

The rapid emergence of Internet of Things (IoT) networks has intensified the demand for sustainable and maintenance-free solutions enabled by energy harvesting (EH). Light-based IoT (LIoT), which exploits indoor illumination for both optical communication and power, offers a promising pathway for zero-energy IoT (ZE-IoT) designs. However, in ZE-LIoT networks, non-uniform illumination and dynamic channel conditions create regions of energy surplus and deficit, while limited energy storage (ES) capacity prevents surplus nodes from harvesting additional energy, resulting in inefficient utilization of available resources. To address these challenges, this paper proposes a data–energy networking-enabled LIoT (DE-LIoT) architecture for indoor wireless personal area networks (WPANs), in which densely distributed, battery-free nodes are coordinated by a central controller. Within this framework, data exchange is performed via optical wireless communication (OWC), while surplus energy is intermittently redistributed through optical wireless power transfer (OWPT). The feasibility of intermittent OWPT is validated through a DE-LIoT prototype implementation, which demonstrates a 50% increase in average illumination at resource-deficient nodes and extends their runtime from 8 h to over 48 h. These results establish DE-LIoT as a promising approach to enhance LIoT applications and pave the way for large-scale, sustainable, and zero-energy IoT deployments, thereby meeting the stringent requirements of 6G IoT networks in terms of energy efficiency, scalability, and environmental sustainability. • Proposes DE-LIoT as an optical-domain data and energy networking framework for battery-free light-based IoT. • Designs and implements a prototype network with battery-free sensor nodes, photovoltaic energy harvesting, optical wireless power transfer, and optical wireless communication. • Validates the DE-LIoT concept experimentally with proof-of-concept access points and nodes, demonstrating extended battery-free operation.