A color space exploration in optical spatial modulation

In order to increase spectrum efficiency, two-dimensional signal space in conventional modulation schemes is expanded by LED transmitter indices in the Optical Spatial Modulation (OSM) scheme, and a combination of transmitter and modulation indices in the Index-based Optical Spatial Modulation (IOSM) scheme. In this paper, we proposed a novel Spatial Modulation called Optical Color-Transmission modes Index-based Spatial Modulation scheme (OCTI-SM) which explore one more dimension - color dimension by using white Laser Diode (LD) light bulb which consists of four color laser sources. With the color space exploration, the proposed scheme achieves higher data rate than the SM schemes. Using computer simulations and mathematical analysis, the system performance of the proposed OCTI-SM is compared with the conventional OSM and the IOSM schemes, and results show that the OCTI-SM achieves a significant improvement in increasing spectral efficiency.