A Simplified Blind Carrier Frequency Offset Estimation Algorithm Based on the Power of Zero-Subcarriers for CO-OFDM Systems

A simplified blind CFO estimation algorithm is proposed for CO-OFDM systems based on the power of zero-subcarriers, which models the cost function as a cosine function, then easily estimating CFO by calculating three test functions. © 2020 The Author(s).

1. Introduction

Coherent optical orthogonal frequency-division multiplexing (CO-OFDM) has been an attractive technology for long-haul optical communication systems due to its high spectral efficiency and excellent tolerance to the fiber chromatic dispersion (CD) and polarization mode dispersion (PMD). However, CO-OFDM is sensitive to the carrier frequency offset (CFO) which is induced by the incoherence between the transmitter laser and the local oscillator (LO). The frequency offset normalized by the subcarrier spacing can be divided into a fractional part and an integral part.