Design and Implementation of Color-Shift Keying for Visible Light Communications

Color-shift keying (CSK) is a visible light communication intensity modulation scheme, outlined in IEEE 802.15.7, that transmits data imperceptibly through the variation of the color emitted by red, green, and blue light emitting diodes. An advantage of CSK is that the power envelope of the transmitted signal is fixed; therefore, CSK reduces the potential for human health complications related to fluctuations in light intensity. In this work, a rigorous design framework for high order CSK constellations is presented. A key benefit of the frame work is that it optimizes constellations while accounting for crosstalk between the color communication channels. In addition, and unlike previous approaches, the method is capable of optimizing 3-D constellations. Furthermore, a prototype CSK communication system is presented to validate the performance of the optimized constellations, which provide gains of 1-3 dB over standard 805.15.7 constellations.