DFT-spread combined with clipping method to reduce the PAPR in VLC-OFDM system

Orthogonal frequency division multiplexing(OFDM) is an attractive technique to realize high data rate in light emitting diodes(LEDs)-based visible light communication(VLC). However, high peak-to-average power ratio(PAPR) of OFDM makes VLC-OFDM very sensitive to the nonlinearity of LEDs. In this paper, the discrete Fourier transform-spread(DFT-spread) combined with clipping method is proposed to reduce the PAPR of OFDM signal in VLC system. Combining simulation with experiment, a performance comparison is made among conventional OFDM, DFT-spread-OFDM, and clipped DFT-spread-OFDM with different clipping ratios(CRs) in a single LED-based VLC system. The experimental results show that the proposed clipped DFT-spread-OFDM method can effectively improve the system performance compared with the other two methods. At the optimum signal peak-to-peak(PTP) value, by using the clipped DFT-spread-OFDM scheme with CR at 8 dB, the bit error rate(BER) of the system can be reduced from 0.003 7 to 0.000 287.