Blind Carrier Frequency Offset Estimation Based on Eighth-Order Statistics for Coherent Optical QAM Systems

Abstract

We propose a carrier frequency offset estimation (FOE) algorithm based on eighth-order statistics for optical quadrature amplitude modulation (QAM) signals. The FOE algorithm does not involve fast Fourier transformation and can be implemented by hardware with little memory and computation resources. Simulation results show that in a 10.709-GBaud/s optical 16-QAM system, carrier frequency offset ranging between 1.25 GHz can be estimated with a uniform standard deviation of 2 MHz when the optical signal-to-noise ratio is 17 dB and symbols are utilized.

Least-squares carrier frequency offset estimation for coherent optical QPSK receivers

“…It not only enables complex modulation formats that utilize both the amplitude and the phase of the optical carrier [1][2], but also facilitates near-ideal compensation of linear transmission impairments such as chromatic dispersion (CD) and polarization mode dispersion (PMD) [3]. In the coherent optical receivers, carrier frequency offset (CFO) estimation and compensation is essential to alleviate the requirement of the center wavelength alignment between the independently-running transmitter laser and the optical local oscillator (LO) [4][5][6][7][8][9][10][11].…”