Improving Lighting Quality and Capacity of OFDM-Based WDM-VLC Systems

Wavelength division multiplexing (WDM) systems in visible light communication are able to increase the data rates by independently modulating colored light sources-generally red, green, and blue. We analytically model such a system using orthogonal frequency division multiplexing modulation and show that the main limitation in achieving higher capacity and illuminance is the red channel. We propose alternate WDM techniques-one which uses an additional red light emitting diode (LED) to offset this effect and another which uses an unmodulated amber LED. By evaluating these systems, we show that increased capacity, higher illuminance range, as well as superior light quality could be achieved by the latter.