Optical- and Induction-Based Data and Energy Networking in Light-Based Internet of Things

Abstract

Optical Wireless Communication (OWC)-based Internet of Things (IoT) technologies are gaining interest with the evolution of 5G and future 6G networks, leveraging the optical spectrum's advantages. The Light-based IoT (LIoT) employs indoor illumination for dual purposes: OWC and photovoltaic Energy Harvesting (EH), promoting battery-free sustainability. However, challenges such as mobility and shadowing in indoor environments can affect OWC and EH performance. To address these challenges, this paper introduces optical-induction data and energy networking. The initial data and energy hop is optical, enabling efficient transfer from the lighting infrastructure to nodes in optimal locations, such as those near light sources with line-of-sight exposure. These resourceful nodes then redistribute data and energy to other nodes in sub-optimal conditions. Subsequent node-to-node data and energy transfers utilise Magnetic Induction (MI) wireless communication and Wireless Power Transfer (WPT). This optical-induction networking ensures efficient data and energy transfer across the LIoT network, despite physical constraints faced by certain nodes. A proof-of-concept optical-to-inductive energy relay was implemented to evaluate this approach. The prototype's performance assessment demonstrates the potential of autonomous optical-to-induction energy transfer relay methods for improving energy distribution in LIoT networks, achieving a maximum energy transfer rate of 6μW under typical indoor lighting conditions.