TY - JOUR
T1 - Efficient Timing/Frequency Synchronization Based on Sparse Fast Fourier Transform
AU - Lu, Jianing
AU - Wu, Qiong
AU - Jiang, Hexun
AU - Fu, Songnian
AU - Tang, Ming
AU - Lu, Chao
N1 - Funding Information:
This work was supported in part by the National Key R and D Program of China under Grant 2018YFB1801301, in part by the Hong Kong Ph.D. Fellowship, in part by the National Natural Science Foundation of China under Grant 61875061 and Grant 61435006, and in part by the 4-BCCK of the Hong Kong Polytechnic University.
Funding Information:
Manuscript received April 11, 2019; revised June 25, 2019; accepted July 27, 2019. Date of publication July 31, 2019; date of current version September 30, 2019. This work was supported in part by the National Key R&D Program of China under Grant 2018YFB1801301, in part by the Hong Kong Ph.D. Fellowship, in part by the National Natural Science Foundation of China under Grant 61875061 and Grant 61435006, and in part by the 4-BCCK of the Hong Kong Polytechnic University. (Corresponding author: Songnian Fu.) J. Lu and C. Lu are with the Photonics Research Centre, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hong Kong (e-mail: jianing.lu@connect.polyu.hk; chao.lu@polyu. edu.hk).
Publisher Copyright:
© 2019 IEEE.
PY - 2019/10/15
Y1 - 2019/10/15
N2 - Efficient synchronization is of great importance for fiber optical coherent communication system. Here, we propose an accurate and low-complexity timing/frequency synchronization scheme based on sparse fast Fourier transform (S-FFT). The proposed scheme consists of coarse timing/frequency synchronization, fine timing synchronization, and fine frequency synchronization. Inspired by the idea of S-FFT, we take full advantages of the sparse nature of training symbols (TSs) and realize the synchronization in the frequency domain. The proposed scheme enables accurate timing synchronization at low signal-to-noise ratio (SNR) region. A complete frequency offset estimation (FOE) range of [-symbol rate/2, + symbol rate/2] can be realized with high resolution. Finally, the proposed scheme is experimentally verified through 10 Gbaud dual-polarization (DP) 16/32-quadrature amplitude modulation (QAM) transmission, without the BER performance penalty. In particular, the total computation complexity is reduced by nearly 200 times in comparison with that using conventional sliding window correlation scheme.
AB - Efficient synchronization is of great importance for fiber optical coherent communication system. Here, we propose an accurate and low-complexity timing/frequency synchronization scheme based on sparse fast Fourier transform (S-FFT). The proposed scheme consists of coarse timing/frequency synchronization, fine timing synchronization, and fine frequency synchronization. Inspired by the idea of S-FFT, we take full advantages of the sparse nature of training symbols (TSs) and realize the synchronization in the frequency domain. The proposed scheme enables accurate timing synchronization at low signal-to-noise ratio (SNR) region. A complete frequency offset estimation (FOE) range of [-symbol rate/2, + symbol rate/2] can be realized with high resolution. Finally, the proposed scheme is experimentally verified through 10 Gbaud dual-polarization (DP) 16/32-quadrature amplitude modulation (QAM) transmission, without the BER performance penalty. In particular, the total computation complexity is reduced by nearly 200 times in comparison with that using conventional sliding window correlation scheme.
KW - Coherent communications
KW - digital signal processing
KW - optical fiber communication
UR - http://www.scopus.com/inward/record.url?scp=85073054652&partnerID=8YFLogxK
U2 - 10.1109/JLT.2019.2932075
DO - 10.1109/JLT.2019.2932075
M3 - Journal article
AN - SCOPUS:85073054652
VL - 37
SP - 5299
EP - 5308
JO - Journal of Lightwave Technology
JF - Journal of Lightwave Technology
SN - 0733-8724
IS - 20
M1 - 8782553
ER -