Time-Domain Blind ICI Mitigation for Non-Constant Modulus Format in CO-OFDM

In this letter, we propose a modified time-domain blind intercarrier interference (ICI) mitigation method for non-constant modulus format (e.g., 16-QAM) in coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. The new algorithm is derived from a blind ICI (BL-ICI) compensation algorithm over constant modulus format for wireless networks. We proposed new power estimation methods for the algorithm to adapt to non-constant modulus format. Our new BL-ICI algorithm is demonstrated to be effective in removing the ICI in a simulated CO-OFDM system over various formats: 8-QAM, 16-QAM, 32-QAM and 64-QAM. It shares the same order of complexity with frequency domain decision-aided ICI compensation method and does not suffer from symbol decision errors.