Spatial Modulation Based Color-Intensity Shift Keying in VLC System

In this paper, a modulation scheme referred as spatial modulation based color-intensity shift keying (SM CISK) is proposed for visible light communication (VLC) systems. The proposed scheme amalgamates conventional color shift keying (CSK), pulse amplitude modulation (PAM), and SM together to efficiently exploit the degrees of freedom in the color, the intensity, and the spatial domains. It maintains a constant average transmit power to fulfill the non-flickering requirement for the normal illumination. The bit error rate (BER) of the proposed scheme is studied based on the maximal likelihood (ML) detection. Simulation results verify that the proposed scheme outperforms the joint color-and-spatial modulation (SM CSK) and CISK modulation scheme.