Skip to main content
Log in

Sampling Frequency Offset Estimation for Pilot-Aided OFDM Systems in Mobile Environment

  • Published:
Wireless Personal Communications Aims and scope Submit manuscript

Abstract

In orthogonal frequency division multiplexing (OFDM) systems, most of the conventional sampling frequency offset (SFO) estimation methods work under the assumption of time-invariant or slow time-variant channels. In mobile environment, the time-variant channel significantly degrades the accuracy of SFO estimation. To solve the problem, we first analyze the properties of time-variant channels. If terminal moves within some tens of the wavelength of radio frequency (RF) signal, channel path delay almost remains unchanged. For most practical OFDM systems, our analysis indicates that channel path delay can be regarded as unchanged during the interval of some tens of OFDM symbols in time-variant channels. Based on the analysis, we propose a novel SFO estimation method for pilot-aided OFDM systems. Different from the conventional methods, the proposed method estimates SFO by detecting the variation of the symbol timing error caused by SFO. The detection is finished by implementing correlation between the channel impulse responses (CIRs) estimated by different OFDM symbols. Performance of the proposed method is simulated and compared with that of two conventional post-FFT methods. Numerical results show that, the proposed SFO estimation method performs better than the conventional methods not only in time-variant channels, but also at low SNRs and large residual carrier frequency offsets (CFOs).

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Speth M., Fechtel S. A., Fock G. (1999) Optimum receiver design for wireless broad-band systems using OFDM I. IEEE Transactions on Communication 47(11): 1668–1677

    Article  Google Scholar 

  2. Liu, S., & Chong, J. (2002). A study of joint tracking algorithms of carrier frequency offset and sampling clock offset for OFDM-based WLANs. In IEEE 2002 International Conference on Communications, Circuits and Systems and West Sino Expositions, 1, pp. 109–113.

  3. Speth M., Fechtel S. A., Fock G. (2001) Optimum receiver design for OFDM-based broadband transmission II. A case study. IEEE Transactions on Communication 49(4): 571–578

    Article  Google Scholar 

  4. Tsai P., Kang H., Chiueh T. (2005) Joint weighted least-squares estimation of carrier-frequency offset and timing offset for OFDM systems over multipath fading channels. IEEE Transactions on Vehicular Technology 54(1): 211–223

    Article  Google Scholar 

  5. Song H., Kim J., You Y. (2009) Pilot-assisted fine frequency synchronization for OFDM-Based DVB receivers. IEEE Transactions on Broadcasting 55(3): 674–678

    Article  Google Scholar 

  6. Langowski, A. (2008). Carrier and sampling frequency offset estimation and tracking in OFDM systems. In 16th International Conference on Software, Telecommunications and Computer Networks, pp. 319–323.

  7. Wang, D., & Hu, A. (2006). A combined residual frequency and sampling clock offset estimation for OFDM systems In IEEE 2002 International Conference on Communications, Circuits and Systems and West Sino Expositions, pp. 1184–1187.

  8. Hung N., Tho L., Chi C. (2009) RLS-Based joint estimation and tracking of channel response, sampling, and carrier frequency offsets for OFDM. IEEE Transactions on Broadcasting 55(1): 84–94

    Article  Google Scholar 

  9. Trigui, I., Affes, S., & Stephenne, A. (2008). ML-based joint estimation of frequency and sampling clock offsets for OFDM systems. In IEEE 9th Workshop on Signal Processing Advances in Wireless Communications, pp. 346–350.

  10. Laourine, A., Stephenne, A., & Affes, S. (2006). Joint carrier and sampling frequency offset estimation based on harmonic retrieval. In IEEE 64th Vehicular Technology Conference, pp. 1–5.

  11. Laourine, A., Stephenne, A., & Affes, S. (2006). Blind sampling clock offset estimation in OFDM systems based on second order statistics, In Fortieth Asilomar Conference on Signals, Systems and Computers, pp. 1782–1785.

  12. Oswald, E. (2004). NDA based feedforward sampling frequency synchronization for OFDM systems. In IEEE 59th Vehicular Technology Conference, 2, pp. 1068–1072.

  13. Bug, S., Wengerter, C., & Gaspard, I., et al. (2001). Channel modeling based on comprehensive measurements for DVB-T mobile applications. In Proceedings of the 18th IEEE Instrumentation and Measurement Technology Conference, 1, pp. 544–548.

  14. Kadel, G., & Lorenz, R.W. (1991). Mobile propagation measurements using a digital channel sounder with a bandwidth matched to the GSM-system. In Seventh International Conference on (IEE) Antennas and Propagation, 1, pp. 496–499.

  15. Kivinen J., Korhonen T.O., Aikio P. et al (1999) Wideband radio channel measurement system at 2 GHz. IEEE transactions on Instrumentation and Measurement 48(1): 39–44

    Article  Google Scholar 

  16. Thoma R. S., Hampicke D., Richter A. J. et al (2000) Identification of time-variant directional mobile radio channels. IEEE transactions on Instrumentation and Measurement 49(2): 357–364

    Article  Google Scholar 

  17. Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for digital terrestrial television, European Telecommunication Standard EN 300 744 VI.5.1, Nov. 2004.

  18. Rugini L., Banelli P. (2005) BER of OFDM systems impaired by carrier frequency offset in multipath fading channels. IEEE Transactions on Wireless Communications 4(5): 2279–2288

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Yuping Zhao.

Additional information

This work was supported by the National Science & Technology Major Project (Project Number 2010ZX030 05-003) established by the People’s Republic of China.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Wu, Y., Zhao, Y. & Li, D. Sampling Frequency Offset Estimation for Pilot-Aided OFDM Systems in Mobile Environment. Wireless Pers Commun 62, 215–226 (2012). https://doi.org/10.1007/s11277-010-0049-x

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11277-010-0049-x

Keywords

Navigation