Lagrange interpolation based extended Kalman filter for phase noise suppression in CO-OFDM system

摘要

In this paper, for the first time, a novel Lagrange interpolation (LRI) based extended Kalman filter (EKF) is proposed to compensate inter-carrier interference (ICI) in coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. Owing to the features of Wiener distribution for laser phase noise, our proposed second-order or higher-order LRI is more suitable for phase fitting than sub-symbol block algorithm based on linear interpolation (LI-SCPEC). Furthermore, to compensate the common phase error (CPE), a modified iteration-free blind (MIFB) algorithm is also designed in this paper. Comparing with the existing common IFB scheme, our method avoids phase misjudgment. By combining the MIFB with the LRI scheme, the accuracy of phase noise estimation and spectrum utilization can be effectively improved. The results of Monte Carlo simulation prove that our proposed scheme is effective in phase noise suppression in CO-OFDM system