Modulation performance for visible light communications

LEDs can transport the signal or data via visible light instead of radio wave in some place that the radio wave will effect the human or damage the component. Therefore, this paper presents about the digital modulation for improving not only data rate and bit error rate but also flickering, colour rendering, dimming range, luminous efficacy rate that are required to keep in a satisfactory level. There are many types of the modulation that have different property. Therefore, the literature review is discussed and shows the comparison of Return-to-zero On-Off Keying (RZ-OOK), Non-Return-to-zero On-Off Keying (NRZOOK), and Binary Phase Shifted Keying (BPSK) in the form of analytical and simulation by the graph of BER versus SNR and also the comparative table of On-Off Keying (OOK), Colour Shifted Keying (CSK), Pulse Position Modulation (PPM), Pulse Width Modulation (PWM), and Orthogonal Frequency Division Multiplexing (OFDM).