3-Color Shift Keying for Indoor Visible Light Communications

We introduce the 3-color shift keying (CSK) modulation for indoor visible light communications (VLC) that is based on the utilization of three symbols, each of which corresponds to a different primary color. In addition, we propose a novel technique that uses sequences of symbols to transmit the information in order to optimize the achieved data rate, while retaining the mean chromaticity constraint that is crucial in VLC systems. Furthermore, the design parameters of 3-CSK are studied and optimized, while an analytical expression for the bit-error-rate is derived. Finally, simulations are used to validate the analysis and to extract insights for the modulation design. The results reveal that 3-CSK offers improved error performance and lower power consumption compared to 4-CSK and On-Off keying, while it retains a relatively high data rate.