Low-complexity colour-shift keying-based visible light communications system

Abstract

Colour-shift keying (CSK) has emerged as a new modulation scheme for indoor visible light communication (VLC) systems, standardised in IEEE 802.15.7. This scheme transmits data by modulating the intensity of red-green-blue light-emitting diodes using a colour coding format. To support VLC, CSK requires the application of multiple light sources and detectors without changing the white light target condition. In this study, a low-complexity VLC system is proposed for multiple light sources that offers important reductions to the overall system complexity while maintaining the compatibility with the premises of the IEEE 802.15.7 standard. The contributions of this work are two-fold. First, a new RGB-based modulation scheme is proposed. This modulation scheme suggests to replace the CSK-based colour coding format by a more flexible, versatile and simplified mapping structure without the need of sending target colour information to the receiver. The second contribution is a novel single-photodiode based receiver that reduces the number of inputs to demodulate RGB signals. Closed-form error performance expressions are verified to analyse the proposed VLC system performance which are verified through Monte Carlo simulations. Finally, the performance of the proposed system is also presented and compared in terms of complexity and throughput efficiency.