Research on multi-color visible light communication system using RZ-4PAM signals with 67% duty cycle

Abstract

In order to improve the transmission performance of visible light communication (VLC) system and user’s demand for large-capacity and high-speed, one multi-color VLC scheme is proposed. This scheme uses red-green-blue light-emitting diode (RGB-LED) as the sender to transmit 4-ary pulse amplitude modulation (4PAM) signals with 67% return-to-zero (RZ). At the receiver, one optical bandpass filter is used for channel separation. By system simulation, we have measured the time-domain waveforms before and after transmission, eye diagrams of the three colors signals, and the bit error rate (BER) performance has been analyzed. The results show that at receiver power of -11dBm, the BER at back-to-back case is slightly lower than that of the signals transmitted in the 8m channel. Since 4PAM signals have higher spectral efficiency compared with the traditional binary signals, this scheme has potential application value in indoor broadband access system.