Theoretical analysis of selective variable rate multi-pulse pulse position modulation for visible light communications

In this paper, we adopt the amount of light actually perceived by the human eye (i.e., normalized perceived light) as a new index for dimming rate control in illumination visible light communication using LEDs as transmitters for illumination, and investigate information modulation and demodulation methods based on the normalized perceived light. In particular, we focus on variable rate multi-pulse pulse position modulation (VR-MPPM), which achieves high spectral efficiency, and propose a method to improve the average spectral efficiency of VR-MPPM based on the normalized perceived light. We evaluate the average spectral efficiency and symbol error rate based on the normalized perceived light from theoretical analysis. As a result, when the lighting function supports the ten step dimming, the proposed system can reduce the required maximum averaged transmitted light power required to achieve 10$^{-3}$ of symbol error rate by about 2dB compared with conventional VR-MPPM.