Signal characterization and achievable transmission rate of VLC under receiver nonlinearity

Strong ambient light and the resultant photoelectric conversion saturation of an avalanche photo diode (APD) may signficantly deteriorate the received signal in visible light communication (VLC) systems. Hence, in this paper we characterize the signal received from an APD under strong ambient light based on our experimental data. To illustrate the phenomenon of APD saturation, we investigate the transmission rate and analyze the link budget. In order to achieve dimming control, we then conceive a unary-coded VLC system for maintaining the user-defined dimming level. We calculate both the upper and lower bounds of the achievable transmission rate of the unary-coded VLC system.<br/