A MB-CAZAC precoding combined with 128/64/32/16-QAM modulation for OFDM-VLC system

In this paper, multi-band constant amplitude zero autocorrelation sequence (MB-CAZAC) precoding combined with the 128/64/32/16-quadrature amplitude modulation (QAM) technology is proposed and experimentally demonstrated in the orthogonal frequency-division multiplexing-based visible light communication (OFDM-VLC) system. By using the MB-CAZAC precoding, it can equalize the uneven signal-to-noise ratio (SNR) and reduce the PAPR compared with the traditional OFDM system. The experimental results show that the 128/64/32/16-QAM MB-CAZAC precoding outperforms the traditional scheme at different data rates for OFDM-VLC system. The spectral efficiency (SE) of the proposed scheme is up to 5.28 b/s/Hz. Meanwhile, it can be successfully transmitted 50-cm free-space at the bit error rate (BER) of 3.82×10−4.