  The growing demand for Internet of Things (IoT) networks has sparked interest
in sustainable, zero-energy designs through Energy Harvesting (EH) to extend
the lifespans of IoT sensors. Visible Light Communication (VLC) is particularly
promising, integrating signal transmission with optical power harvesting to
enable both data exchange and energy transfer in indoor network nodes. VLC
indoor channels, however, can be unstable due to their line-of-sight nature and
indoor movements. In conventional EH-based IoT networks, maximum Energy Storage
(ES) capacity might halt further harvesting or waste excess energy, leading to
resource inefficiency. Addressing these issues, this paper proposes a novel
VLC-based WPANs concept that enhances both data and energy harvesting
efficiency. The architecture employs densely distributed nodes and a central
controller for simultaneous data and energy network operation, ensuring
efficient energy exchange and resource optimisation. This approach, with
centralised control and energy-state-aware nodes, aims for long-term energy
autonomy. The feasibility of the Data-Energy Networking-enabled Light-based
Internet of Things (DE-LIoT) concept is validated through real hardware
implementation, demonstrating its sustainability and practical applicability.
Results show significant improvements in the lifetime of resource-limited
nodes, confirming the effectiveness of this new data and energy networking
model in enhancing sustainability and resource optimisation in VLC-based WPANs.
