Dimming schemes for visible light communication: the state of research

As a new generation green lighting source, the light emitting diode (LED) is rapidly replacing traditional incandescent and fluorescent light sources. Apart from providing energy savings, the use of LED lighting technology creates scope for an innovative optical wireless communication technology known as visible light communication (VLC), which takes advantage of the superior modulation capability of LEDs to transmit data through a wireless channel. VLC is capable of concurrently providing communication as well as illumination. For making commercial implementation of VLC feasible, it is necessary to incorporate it with dimming schemes that will provide energy savings, moods, and increase the aesthetic value of the place using this technology. However, general dimming techniques have an adverse effect on communication since they limit the achievable data rate of a VLC link. This drives the necessity of formulating efficient dimming techniques, which will create a balance between the two most basic functions of VLC: illumination and communication. This paper focuses on dimming mechanisms that can be implemented in VLC systems to save energy and provide precise illumination control. The motivation behind this control mechanism, current challenges in practical implementation, driver circuitry, recent progress, and future prospects are also concisely presented.