Low complexity, modulation-transparent and joint polarization and phase tracking scheme based on the nonlinear principal component analysis

A low complexity, modulation-transparent and joint polarization and phase tracking scheme based on the nonlinear principal component analysis (NPCA) is proposed and demonstrated via both simulation and experiment. Based on high-order statistics, NPCA can achieve joint polarization and phase tracking successfully without any prior information of modulation format. Meanwhile, owing to fact that the estimated matrix is constrained to be a unitary matrix, NPCA can avoid the singularity problem. Compared with the format dependent scheme such as CMA/MMA + VVPE, NPCA shows comparable BER performance under the back-to-back case and shows fast-tracking capability over wide polarization rotation rates ranges. Moreover, for 16QAM signals, the proposed NPCA-based scheme has reduced around 30% computation resources compared with the format dependent scheme, which confirms the advantage of low implementation complexity.