In this paper, the peak-to-average power ratio(PAPR) of orthogonal frequency division multiplexing(OFDM) signal is reduced by combining the discrete cosine transform(DCT) with clipping in optical intensity-modulated direct-detection(IM/DD) OFDM systems. First, the data are transformed into new modified data by DCT. Second, the proposed scheme utilizes the clipping technique to further reduce the PAPR of OFDM signal. We experimentally demonstrate that the optical OFDM transmission system with this proposed scheme can achieve significant performance improvement in terms of PAPR and bit error rate(BER) compared with the original optical OFDM systems.
We experimentally assess the bit error rate(BER) performance of an intensity modulation/direct detection(IM/DD) optical orthogonal frequency division multiplexing(OFDM) system based on discrete Hartley transform(DHT) precoding in single-mode fiber(SMF) link for 2.5 Gbit/s quadrature phase shift keying(QPSK) OFDM symbol rate.The experimental results show that for the optical OFDM system based on DHT-precoding,the receiver sensitivity at the BER of 10-4 after 100 km SMF transmission is about 1.5 dBm better than that of the original QPSK OFDM signal,and the DHT-precoded OFDM QPSK signal can achieve approximately 1.3 dB of peak-to-average power ratio(PAPR) reduction.
An efficient post-coding strategy is proposed in this letter to reduce the peak-to-average power ratio(PAPR) of orthogonal frequency division multiplexing(OFDM) signals for optical intensity modulated direct detection(IM/DD) systems. The post-coding scheme based on discrete cosine transform(DCT) is employed after the inverse fast Fourier transform(IFFT) in the transmitter to reduce the PAPR of OFDM signals. This method is different from the conventional pre-coding scheme which is employed before IFFT operation. Numerical simulations demonstrate that the new DCT post-coding strategy can significantly reduce the PAPR than the conventional pre-coding scheme. Meantime, the bit error rate(BER) performance of the proposed post-coding system can be improved compared with the conventional pre-coding scheme.
