Advertisement

Joint timing and frequency synchronization in coherent optical OFDM systems

  • Xinwei Du
  • Pooi-Yuen Kam
  • Changyuan YuEmail author
Review Article
  • 2 Downloads

Abstract

In this paper, we review our joint timing and frequency synchronization algorithms in coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. We first present a timing estimation method by designing the pattern of the training symbol, whose timing metric has a sharp and clear peak, to ensure accurate timing offset (TO) estimation performance. Then we provide both data-aided (DA) and blind (BL) approaches to estimate the carrier frequency offset (CFO). For the DA algorithm, we utilize the same training symbol structure as the timing estimation does, while for the BL algorithm, we utilize the zero-subcarrier power (ZSP) to achieve full-range CFO estimation. Note that our joint timing and frequency synchronization approaches require only one OFDM symbol, which ensure not only the data transmission efficiency, but also the TO and CFO estimation performance. A modified BL ZSP algorithm is proposed to further improve the CFO estimation performance by taking the power average over a series of OFDM symbols. The effectiveness of the TO estimation algorithm, and both the DA and BL CFO estimation algorithms are verified and demonstrated in both simulations and experiments.

Keywords

timing offset (TO) carrier frequency offset (CFO) coherent optical orthogonal frequency division multiplexing (CO-OFDM) zero-subcarrier power (ZSP) 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Notes

Acknowledgements

The authors would like to thank the supports of Grants 61501313, 61571316 and 61302112 from NSFC and Grant 1-ZE5K from the Hong Kong Polytechnic University.

References

  1. 1.
    Shieh W, Djordjevic I. OFDM for Optical Communications. Burlington: Academic Press, 2009Google Scholar
  2. 2.
    Shieh W, Athaudage C. Coherent optical orthogonal frequency division multiplexing. Electronics Letters, 2006, 42(10): 587–589CrossRefGoogle Scholar
  3. 3.
    Hara S, Prasad R. Multicarrier Techniques for 4G Mobile Communiations. Norwood, MA: Artech House, 2003Google Scholar
  4. 4.
    Pollet T, Van Bladel M, Moeneclaey M. BER sensitivity of OFDM systems to carrier frequency offset and wiener phase noise. IEEE Transactions on Communications, 1995, 43(2–4): 191–193CrossRefGoogle Scholar
  5. 5.
    Abdzadeh-Ziabari H, Zhu W P, Swamy M N S. Joint maximum likelihood timing, frequency offset, and doubly selective channel estiamtion for OFDM systems. IEEE Transactions on Vehicular Technology, 2018, 67(3): 2787–2791CrossRefGoogle Scholar
  6. 6.
    Lin D D, Pacheco R A, Lim T J, Hatzinakos D. Joint estimation of channel response, frequency offset, and phase noise in OFDM. IEEE Transactions on Signal Processing, 2006, 54(9): 3542–3554CrossRefzbMATHGoogle Scholar
  7. 7.
    van de Beek J J, Sandell M, Borjesson P O. ML estimation of time and frequency offset in OFDM systems. IEEE Transactions on Signal Processing, 1997, 45(7): 1800–1805CrossRefzbMATHGoogle Scholar
  8. 8.
    Schmidl T M, Cox D C. Robust frequency and timing synchronization for OFDM. IEEE Transactions on Communications, 1997, 45 (12): 1613–1621CrossRefGoogle Scholar
  9. 9.
    Minn H, Zeng M, Bhargava V K. On timing offset estimation for OFDM systems. IEEE Communications Letters, 2000, 4(7): 242–244CrossRefGoogle Scholar
  10. 10.
    Park B, Cheon H, Kang C, Hong D. A novel timing estimation method for OFDM systems. IEEE Communications Letters, 2003, 7 (5): 239–241CrossRefGoogle Scholar
  11. 11.
    Du X, Zhang J, Xu Z, Yu C. A novel timing estimation method for coherent optical OFDM systems. In: Proceedings of Asia Communications and Photonics Conference. Optical Society of America, 2015, paper AS4F. 5Google Scholar
  12. 12.
    Du X, Zhang J, Li Y, Yu C, Kam P Y. Efficient joint timing and frequency synchronization algorithm for coherent optical OFDM systems. Optics Express, 2016, 24(17): 19969–19977CrossRefGoogle Scholar
  13. 13.
    Cao S, Zhang S, Yu C, Kam P Y. Full-range pilot-assisted frequency offset estimation for OFDM systems. In: Proceedings of Optical Fiber Communication Conference/National Fiber Optic Engineers Conference. Optical Society of America, 2013, paper JW2A. 53Google Scholar
  14. 14.
    Zhou X, Long K, Li R, Yang X, Zhang Z. A simple and efficient frequency offset estimation algorithm for high-speed coherent optical OFDM systems. Optics Express, 2012, 20(7): 7350–7361CrossRefGoogle Scholar
  15. 15.
    Wu J, Tang M, Xu L, Zhu S, Cheng J, Feng Z, Zhang L, Wang X, Lin R, Deng L, Fu S, Shum P P, Liu D. A robust and efficient frequency offset correction algorithm with experimental verification for coherent optical OFDM system. Journal of Lightwave Technology, 2015, 33(18): 3801–3807CrossRefGoogle Scholar
  16. 16.
    Kim D K, Do S H, Lee H K, Choi H J. Performance evaluations of the frequency detectors for orthogonal frequency division multiplexing. IEEE Transactions on Consumer Electronics, 1997, 43(3): 776–783CrossRefGoogle Scholar
  17. 17.
    Huang Y J, Wei S W. Modified guard band power detection for coarse carrier frequency offset receovery in OFDM system. Wireless Personal Communications, 2008, 45(2): 163–173CrossRefGoogle Scholar
  18. 18.
    Du X, Zhang J, Yu C, Kam P Y. Blind carrier frequency offset estimation for coherent optical OFDM systems. In: Proceedings of Advanced Photonics (IPR, NOMA, Sensors, Networks, SPPCom, SOF). Optical Society of America, 2016, paper SpW2G.3Google Scholar
  19. 19.
    Zhu P, Li J, Zhao H, Tian Y, Chen Y, Wu Z, Chen Z, He Y. An iterative frequency offset estimation method for coherent optical OFDM system. IEEE Photonics Technology Letters, 2017, 29(11): 877–880CrossRefGoogle Scholar
  20. 20.
    Jignesh J, Corcoran B, Zhu C, Lowery A. Simple optoelectronic frequency-offset estimator for coherent optical OFDM. Optics Express, 2017, 25(25): 32161–32177CrossRefGoogle Scholar

Copyright information

© Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Electrical and Computer EngineeringNational University of SingaporeSingaporeSingapore
  2. 2.National University of Singapore (Suzhou) Research InstituteSuzhouChina
  3. 3.Department of Electrical and Information EngineeringThe Hong Kong Polytechnic UniversityHong KongChina

Personalised recommendations