A Novel Frequency Domain Channel Estimation Method for Optical OFDM/OQAM

Abstract

Orthogonal frequency division multiplexing (OFDM) combined with offset quadrature amplitude modulation (OQAM) have aroused wide interest for optical communication recently. With the relaxation of orthogonal condition from the complex field to the real field, optical OFDM/OQAM faced with serious intrinsic imaginary interference (IMI) brought by chromatic dispersion and polarization mode dispersion. As have been discussed in previous publications, frequency domain channel estimation methods utilizing the concept of pseudo pilot have been proved effective in combating IMI. In this paper, we discussed a novel frequency domain channel estimation method based on the using of three consecutive full loaded pilot blocks for optical OFDM/OQAM system. In this approach, the pseudo pilot was constructed with three consecutive loaded pilot blocks. The discussed method can efficiently promote the power of the pseudo-pilot and improve the system robustness against IMI effect significantly. As demonstrated in the Montel Carlo simulation results, 1.8dB advantage in require optical signaI to noise ratio (OSNR) at a BER target of $10^{-3}$ could be achieved with the using of the discussed method, compared with the IAM-C method.