Adaptive multi-color shift keying constellation design for visible light communications considering lighting requirement

In visible light communications (VLCs), light-emitting diodes (LEDs) are utilized for communication and lighting simultaneously. Therefore, in VLC systems, it is necessary to jointly consider communication quality and lighting level. For multi-color VLC systems, although optical filters are used on the receiving end, there is still multi-color crosstalk inevitably. In this work, an adaptive multi-color constellation design framework of color shift keying (CSK) modulation is established for VLC systems based on multi-color LEDs, with consideration of the channel state information. To achieve joint communication and illumination, we optimize the Euclidean distance of received signal with signal amplitude constraint, chromaticity constraint and luminance constraint. Further, with the linear approximation of Taylor series, a constellation design is attained to control multi-color crosstalk. The numerical results show that our proposed adaptive constellation design has better symbol error rate (SER) performance than CSK constellation design.