A Novel ACO-OFDM Scheme for Optical Wireless Communications

In this paper, a novel asymmetrically clipping optical frequency-division multiplexing (ACO-OFDM) scheme which can improve the transmission data rate, spectrum efficiency and system performance of traditional ACO-OFDM and DC biased optical OFDM (DCO-OFDM) schemes to support the transmission requirements of optical wireless communications (OWCs) is proposed. The proposed ACO-OFDM scheme mainly utilizes both odd subcarriers and even subcarriers for the data transmission and additionally uses the unipolar pulse amplitude modulation (U-PAM) technique for encoding the polarity information of even subcarriers at the transmitter. Moreover, the proposed ACO-OFDM scheme also can estimate the noise effect at even subcarriers caused by the data transmission of odd subcarriers at the receiver and further compensate the effect of the clipping noise, thus it can also improve the system performance of the proposed ACO-OFDM scheme effectively.