ACO-OFDM Diversity Combining Receiver with Direct Current Offset in Visible Light Communications

Aiming at the asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) systems with direct current (DC) offset, a diversity combining receiver using single fast Fourier transform (FFT) is proposed. In a visible light communication (VLC) system, the background light source will inevitably cause a DC offset at the receiving end. Through the symmetric recovery operation, the odd and even signals of the ACO-OFDM system can be reconstructed in the time domain to estimate the DC offset of the system. The results show that the proposed diversity combining receiver has lower complexity, is insensitive to DC components, and has the same diversity gain as that of the conventional diversity combining receiver.