Networked Indoor Lighting Controls with Visible Light Communication

Intelligent lighting systems employ dimmable luminaires, photosensors, and occupancy sensors to adapt to daylight and user presence conditions in indoor environments. By providing the illumination required for users and no more, significant energy savings can be made. The state of the art in these lighting systems currently relies on dedicated communication hardware such as radio networking modules. Additionally, the state of the art relies on parameters specific for the environment to be known called the optical channel gains. Although these may be measured in a calibration step while the system is offline, occupants interacting with the environment affect the optical channel gains. Currently, such environment changes can compromise the desired control behavior of intelligent lighting systems. Visible light communication (VLC) presents an alternative to radio communication in networked lighting control systems. It reuses the system’s luminaires as transmitters and its photosensors as receivers. This way, dedicated communication hardware is no longer required. Furthermore, the reception of signals on the optical channel between luminaires and photosensors allows for the estimation of the optical channel gains. By estimating these during communication, the system becomes adaptable to changes in the environment. The proposed system is evaluated against the state of the art in radionetworked lighting control using simulations as well as an experimental testbed. The VLC-networked lighting control system is shown to be resilient against changes to the environment which the state of the art systems are compromised by.