Robustness analysis of O-FDE algorithm for dispersion compensation in coherent fiber optical communications

The overlapping frequency domain equalization(O-FDE) in digital signal processing(DSP) is frequently employed to provide dispersion compensation in long-distance coherent fiber optical communications. However, the change in overlapping symbol length that occurs during the processing of the O-FDE algorithm will typically be influenced by the decision and zero filling of the last subblock, which is harmful to the robustness of the O-FDE algorithm. In this study, with a thorough robustness analysis on changing overlapping symbol length, we present a novel method for decision and zero filling of the last subblock and examine the correspondingly resulting error vector magnitude(EVM) and symbol error ratio(SER) under different values of optical signal-to-noise ratio(OSNR), chromatic dispersion, and overlapped symbol lengths.