Back to Search
Start Over
Low Complexity Two-Stage FOE Using Modified Zoom-FFT for Coherent Optical M-QAM Systems.
- Source :
- IEEE Photonics Technology Letters; 3/1/2020, Vol. 32 Issue 5, p263-266, 4p
- Publication Year :
- 2020
-
Abstract
- We propose a novel low complexity two-stage frequency offset estimation (FOE) scheme based on modified Zoom-FFT for square 16/64-quadrature amplitude modulation (QAM) coherent optical systems. The first stage roughly estimates the frequency offset through a small size FFT. After frequency shifting, the modified Zoom-FFT can select and reconstruct the spectrum of interest by time domain average. Since the average provides a good estimate of the amplitudes of the frequency components, we can accurately find the peak after the second-stage FFT. We conduct simulations and compare the normalized frequency variance of the proposed scheme with different algorithms, e.g., the single-stage FFT and the Chirp-Z transform (CZT). The simulation results show that the proposed FOE scheme has the similar normalized frequency variance as other algorithms of $4.0\times 10^{-9}$ and $1.6\times 10^{-9}$ for 16QAM and 64QAM, respectively. The numerical simulations and experimental results demonstrate that the proposed scheme can achieve comparable performance, while the complexity is reduced by 86.6% (81.2%) and 60.9% (61.2%) for 16QAM (64QAM) compared with single-stage FFT and FFT+CZT, respectively. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10411135
- Volume :
- 32
- Issue :
- 5
- Database :
- Complementary Index
- Journal :
- IEEE Photonics Technology Letters
- Publication Type :
- Academic Journal
- Accession number :
- 142488079
- Full Text :
- https://doi.org/10.1109/LPT.2020.2969701