Color-shift keying (CSK) is a visible light communication (VLC) intensity modulation scheme, outlined in IEEE 802.15.7, that transmits data imperceptibly through the variation of the light color emitted by a red, green, and blue (RGB) light emitting diode (LED). Unlike other intensity modulation schemes, CSK guarantees that the intensity of the luminary will not fluctuate, thus limiting potential human health complications related to flickering light.
In this work, a rigorous design framework for CSK constellations is presented. The benefits of the frame work are that it can optimize constellations while accounting for cross talk between the color communication channels formed by the colored LEDs. Unlike previous works, the method applies the study of colorimetry to optimize higher order CSK constellations such that the luminary functions with a desired operating color, allowing constellations to be designed to meet lighting industry quality metrics.
This work concludes with the implementation of a CSK communication channel for the purposes of measuring the symbol error rate (SER) versus signal to noise ratio (SNR) of CSK constellations. It is demonstrated that the optimized constellations can achieve equal performance to the standardized constellations, outlined in Section 12 of IEEE 802.15.7, while only requiring half the transmitted power.