Data transmission scheme based on the DC-QOSTBC in indoor MIMO-VLC systems

We propose a data transmission scheme based on the dimming coding and quasi-orthogonal space-time block coding (QOSTBC) to improve the performance of indoor multiple-input multiple-output visible-light communication (MIMO-VLC) systems. After channel coding, the dimming coding was first applied to encode the input information bits into dimming bits. Then these encoded dimming bits were mapped to different symbols by head pulse position modulation. Finally, the symbol matrix was constructed on the basis of QOSTBC; then the light-emitting diodes would be activated to transmit the optical signals carrying the information according to the symbol matrix. The Monte Carlo simulations demonstrated the superiority of the proposed scheme in channel capacity and bit error ratio (BER). The channel capacity was a good approximation to the actual one, even though the full diversity gain could not be completely achieved. The BER could achieve 0.4×10^-6 when the number of photodetectors was two.