Abstract:

In order to increase the transmission rate of visible light communication system, using OFDM(Orthogonal FrequencyDivision Multiplexing) modulation techniques, a transmitter of visible light communication system is designed based on DSP processor. The hardware system includes DSP electrical platform, D/A conversion circuit and Bias-tee/LED driver circuit. The software system includes 16PSK modulation scheme to encode OFDM sub-channels, to enhance antinoise capability of the system enhanced, so that it can not be affected when the channel characteristics changed. Experimental results show that OFDM transmits data frames may be implemented by the transmitter of VLC (Visible Light Communication) system based on OFDM. The effective data transfer rate of the sender is 18 kbit/s when the modulation method is 16PSK, IFFT(Inverse Fast Fourier Transform) is calculated as 16order radix2 fast Fourier transform algorithm. The load resistance is greater, the waveform distortion of OFDM output signal by the LED(Light Emitting Diode) driver circuit is less. Since the OFDM technology has been transplanted into a visible light communication system developed, the data transfer rate of the system is improved, effectively suppressing ISI(Inter-Symbol Interference) and ICI(Inter-Carrier Interference) caused by the channel fading and delay.

Key words: visible light communication（VLC）, orthogonal frequencydivision multiplexing（OFDM）, white light emitting