A new improved-performance decoding technique for Asymmetrically-Clipped Optical-OFDM

A novel scheme for demodulation of ACO-OFDM in the presence of DC offset

“…At receiver end, several different demodulation schemes are evaluated for comparison. Besides the proposed scheme, they include the OSCS, the PMLS, the DCS and its improved version IDCS with weighting factor [20][21][22] α ¼ 0.5. As optical OFDM has strong tolerance to attenuation and dispersion, we assume in the simulations that channel losses and dispersion are fully compensated by the equalizer.…”

“…In [23,24], by making use of the anti-symmetry property of ACO-OFDM signal, a pairwise maximum likelihood scheme (PMLS) was developed to cancel a significant amount of noise before demodulation of ACO-OFDM. Compared with the OSCS, both the DCS and the PMLS can achieve up to 3 dB performance gain [21,24]. It had been expected that joint utilization of the DCS and the PMLS can lead to further improvement.…”

“…However, as a key challenge, improving the demodulation performance of ACO-OFDM in practical systems has not been well addressed. In the odd sub-carrier scheme (OSCS) [14], the clipping noise on even subcarriers was simply discarded, while later researches [20][21][22] revealed that the residual information carried by the clipping noise can be further explored to improve demodulation performance. Based on the fact that the clipping noise is equal to half of the absolute values of un-clipped amplitude, a diversity combining scheme (DCS) was proposed in [20] and then studied in [21,22] to combine the odd sub-carrier signal with the clipping noise in a non-linear way.…”

“…In the odd sub-carrier scheme (OSCS) [14], the clipping noise on even subcarriers was simply discarded, while later researches [20][21][22] revealed that the residual information carried by the clipping noise can be further explored to improve demodulation performance. Based on the fact that the clipping noise is equal to half of the absolute values of un-clipped amplitude, a diversity combining scheme (DCS) was proposed in [20] and then studied in [21,22] to combine the odd sub-carrier signal with the clipping noise in a non-linear way. In [23,24], by making use of the anti-symmetry property of ACO-OFDM signal, a pairwise maximum likelihood scheme (PMLS) was developed to cancel a significant amount of noise before demodulation of ACO-OFDM.…”

“…Several schemes [14,[20][21][22][23][24][25][26] have been established for demodulation of ACO-OFDM. However, as a key challenge, improving the demodulation performance of ACO-OFDM in practical systems has not been well addressed.…”