Deflected field-of-views receiver for indoor MIMO visible light communications

Conventional non-imaging receiver for multiple-input-multiple-output (MIMO) visible light communications (VLC) systems always suffer from the problem of ill-conditioned channel matrix due to the high correlation among sub-channels. So in this paper, a deflected field-of-views (FOVs) receiver for MIMO VLC system is proposed to reduce the correlation and also have a compact planar structure. The receiver has a diaphragm with several apertures to cover the planar array of photodetectors (PDs), so each PD will own different deflected FOV. Considering the diversity of sub-channels, the precoding method and water-filling algorithm are applied at the transmitters to achieve higher data rate or lower power consumption. In the simulation, the optimal structure parameter of the receiver is demonstrated, and the BER performance of the receiver is also verified, where DC-biased Optical orthogonal frequency division multiplexing (DCO-OFDM) is applied. The results show that the precoding method can significantly improve the system performance and is therefore, perfectly suitable for the deflected FOVs receiver in MIMO-VLC systems.