An efficient MIMO–OFDM VLC system of combining space time block coding with orthogonal circulant matrix transform precoding

Abstract An efficient precoding scheme combining space-time block code (STBC) and orthogonal circulant matrix transform (OCT) is proposed to improve the performance of multiple input–multiple output-orthogonal frequency division multiplexing (MIMO–OFDM) based visible light communication (VLC) systems in this work. An experimental 2 × 2 MIMO–OFDM VLC system is designed and setup to evaluate the performance of the proposed STBC–OCT precoding scheme, which bit error rate (BER) performance is investigated experimentally for different sample rates, amplitudes and quadrature amplitude modulation (QAM) order. It is shown that the system using proposed STBC–OCT precoding has more excellent BER performance compared with the system using other precoding methods, and 157.5 Mbit/s transmission rate can be realized for the MIMO VLC system with 0.5 m distance. This is because that the proposed scheme can effectively alleviate the bandwidth limitation issue of the VLC system and offers the optimal reliability.