The color shift key modulation with non-uniform signaling for visible light communication

Color shift key (CSK) modulation method is a new modulation method for visible light communication (VLC) system, which transmits information through the light´s color property of a multi-color light source, typically a RGB LED. This paper analyzes the illumination and communication performances of CSK signals, including flicker effect, dimming range, color rendering index (CRI), luminous efficacy rate (LER), variable data rate and error probability, and also generates the optimized power weights combination group of the red, green and blue light emitted from a RGB LED, which meet the current illumination requirements, through a 2 level non-uniform signaling method, and analytical and simulation result shows a not good enough bit error rate (BER) performance. Maximum correlation coefficient and minimum RGB space distance demodulation methods with better BER performance are also discussed, simulation result shows a close relationship between the BER performance and both the entire valid CSK signals and demodulation method. Finally, a tradeoff of the CRI is discussed.