High Accuracy and Low Complexity Frequency Offset Estimation Based on All-Phase FFT for M-QAM Coherent Optical Systems

TL;DR

This paper introduces a low complexity frequency offset estimation algorithm for M-QAM coherent optical systems using all-phase FFT, achieving significant computational savings while maintaining accuracy.

Contribution

The proposed all-phase FFT-based algorithm reduces computational complexity by up to 73% compared to existing two-stage methods without sacrificing estimation accuracy.

Findings

73% reduction in computational complexity

Maintains estimation accuracy comparable to existing methods

Applicable to M-QAM coherent optical systems

Abstract

A low complexity frequency offset estimation algorithm based on all-phase FFT for M-QAM is proposed. Compared with two-stage algorithms such as FFT+CZT and FFT+ZoomFFT, our algorithm can lower computational complexity by 73% and 30% respectively, without loss of the estimation accuracy.