On the LED Efficacy and Modulation Design Space for Visible Light Communication

Abstract

As a new trend in short-range wireless digital communications, Visible Light Communication (VLC) comes as a promise breakthrough for the industry and lighting systems designers. Such technology makes use of Light Emitting Diodes (LEDs) as transmitters of data signals by modulating light intensity. However, a possible barrier to the wider adoption of VLC is the global efficacy of the lighting system: lighting rise efficacy of LED devices and industrial standards may be harmed by intentional power modulation of light for communication. It has been shown that the modulation of light intensity brings unavoidable extra power expense. In this sense, this paper brings an analysis of the LED concerning its operating limits and efficacy with intentional modulation for VLC. Moreover, a design space is defined connecting a set of possible modulation schemes with the desired total light flux. This analysis guides the selection of the modulation technique according to the available power for a VLC system efficacy constrained. We also show that the decrease in LED efficacy follows same drop behavior for all the modulation techniques selected.