Study of Dimming and LED Nonlinearity for ACO-OFDM Based VLC Systems
In this paper, the performance of an Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing (ACOOFDM) indoor wireless system is investigated. In particular, the illuminance distribution inside a room (5m?5m?3 m) under different brightness conditions, i.e. dimming levels, and the electrical Signal-to-Noise Ratio (SNR) at the receiver are considered. The system performance is also assessed in terms of Bit-Error Ratio (BER) as a function of average transmitted optical power. Brightness control is achieved using the Continuous Current Reduction (CCR) technique to assure higher luminous efficacy compared to the Pulse-Width Modulation (PWM) dimming technique. In addition, the impact of the induced distortions due to the nonlinear behavior of the Light-Emitting Diode (LED) as a light source is included in the simulation model.