Analysis of the Pseudo Pilot in Optical OFDM/OQAM System

Orthogonal frequency division multiplexing (OFDM/OQAM) offset orthogonal amplitude modulation (OFDM/OQAM) systems have attracted wide attention due to their high spectral efficiency and low out-of-band power radiation. However, the OFDM/OQAM system has inherent virtual interference (IMI) and nonlinear interference (NI) in the face of multipath fading channel. Therefore, the development of effective channel estimation methods and pseudo-pilots to suppress IMI and NI effects is very important to maintain the performance of OFDM/OQAM systems. In order to reduce the interference caused by the correlation characteristics, the interference approximate expansion method (IAM-E) is proposed in this paper. The time-frequency localization (TFL) properties of IOTA filters in O-OFDM/OQAM systems are analyzed, and the least squares estimation of the channel transmission matrix in frequency domain is carried out. Theoretical analysis and simulation results show that IAM-E is an effective interference suppression method.