Dimming Techniques of Visible Light Communications for Human-Centric Illumination Networks: State-of-the-Art, Challenges, and Trends

Abstract

Visible light communication (VLC), which utilizes the ubiquitous illumination network to implement high-speed communication, is rapidly emerging as one promising candidate to complement conventional radio frequency communication. In practical VLC systems, the illumination network is required to be human-centric to provide adjustable lighting for different user requirements, which limits the resource utilization of the communication aspect. Dimming control techniques, which provide compromise resource management solutions between illumination and communication, are critically essential in the implementation and commercialization of VLC. In this article, state-of-the-art dimming techniques for VLC are illustrated from a multi-dimensional perspective, including the intensity domain, the time domain, the frequency domain, and the spatial domain. We provide a comprehensive comparison of these techniques on their principles, key features, system performance, and so on. In addition, the challenges and the future research trends are presented to provide researchers with insights of future improvements and prospect of advancement in the field. Moreover, the concept of the software defined multi-dimensional dimming is also proposed for the human-centric illumination network by utilizing multi-dimensional resources according to the diversified system requirements.