Hybrid orthogonal frequency division multiplexing (H-OFDM) for visible light communication

In this paper, we present a novel hybrid orthogonal frequency division multiplexing (H-OFDM) for visible light communication (VLC). H-OFDM uses a combination of DC-bias optical OFDM (DCO-OFDM) and asymmetrically clipped optical OFDM (ACO-OFDM) techniques. In this hybrid technique, the absolute value of bipolar DCOOFDM signal is used to carry amplitude information in the first block, while the ACO-OFDM signal is used to transmit the polarity information of the DCO-OFDM signal in the second block. This new technique does not need any DC bias and could achieve maximum 33.3% increase of data rate with 256-QAM in theory. Extensive simulations notice that H-OFDM results in almost 3 dB performance improvement with an additive white Gaussian noise. In addition, it saves up to 2 dB input electrical average power when negative clipper and power allocation are applied. Therefore, with no DC bias, data rate increment and power efficient, H-OFDM seems to be an attractive technique for VLC system using intensity modulated direct detection (IM/DD).