Skip to main content
Log in

Maximum-Likelihood Estimator for Coarse Carrier Frequency Offset Estimation in OFDM Systems

  • Published:
Wireless Personal Communications Aims and scope Submit manuscript

Abstract

Orthogonal frequency division multiplexing (OFDM) systems are more sensitive to carrier frequency offset (CFO) compared to the conventional single carrier systems. CFO destroys the orthogonality among subcarriers, resulting in inter-carrier interference (ICI) and degrading system performance. To mitigate the effect of the CFO, it has to be estimated and compensated before the demodulation. The CFO can be divided into an integer part and a fractional part. In this paper, we investigate a maximum-likelihood estimator (MLE) for estimating the integer part of the CFO in OFDM systems, which requires only one OFDM block as the pilot symbols. To reduce the computational complexity of the MLE and improve the bandwidth efficiency, a suboptimum estimator (Sub MLE) is studied. Based on the hypothesis testing method, a threshold Sub MLE (T-Sub MLE) is proposed to further reduce the computational complexity. The performance analysis of the proposed T-Sub MLE is obtained and the analytical results match the simulation results well. Numerical results show that the proposed estimators are effective and reliable in both additive white Gaussian noise (AWGN) and frequency-selective fading channels in OFDM systems.

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.

Similar content being viewed by others

References

  1. Standard, E. T. (1994). Radio broadcast systems; digital audio broadcasting (DAB) to mobile, portable, and fixed receivers. preETS 300 401, Tech. Rep., March 1994.

  2. Reimers U. (1995) DVB-T: The COFDM based system for terrestrial television. Electronics & Communications Engineering Journal 9: 28–32

    Article  Google Scholar 

  3. IEEE Std. 802.11a. (1999). Wireless LAN medium access control (MAC) and physical layer (PHY) specifications: High-speed physical layer extension in the 5-GHz band. IEEE, 1999.

  4. Khun-Jush, J., Schramm, P., Wachsmann, U., & Wenger, F. (1999). Structure and performance of the HIPERLAN/2 physical layer. In Proceedings of Vehicular Technology Conference (Vol. 5, pp. 2667–2671). Amsterdam, The Netherlands.

  5. Pollet T., Van Bladel M., Moeneclaey M. (1995) BER sensitivity of OFDM systems to carrier frequency offset and Wiener phase noise. IEEE Transactions on Communications 43(2): 191–193

    Article  Google Scholar 

  6. Moose P.H. (1994) A technique for orthogonal frequency division multiplexing frequency offset correction. IEEE Transactions on Communications 42(10): 2908–2914

    Article  Google Scholar 

  7. Yang F., Li K.H., Teh K.C. (1997) A carrier frequency offset estimator with minimum output variance for OFDM systems. IEEE Communications Letters 8(11): 677–679

    Article  Google Scholar 

  8. van de Beek J.J., Sandell M., Borjesson P.O. (1997) ML estimation of time and frequency offset in OFDM systems. IEEE Transactions on Signal Processing 45(7): 1800–1805

    Article  MATH  Google Scholar 

  9. Tureli U., Kivanc D., Liu H. (2001) Experimental and analytical studies on a high-resolution OFDM carrier frequency offset estimator. IEEE Transactions on Vehicular Technology 50(2): 629–643

    Article  Google Scholar 

  10. Huang D., Letaief K.B. (2006) Carrier frequency offset estimation for OFDM systems using null subcarriers. IEEE Transactions on Commununications 54(5): 813–823

    Article  Google Scholar 

  11. Schmidl T.M., Cox D.C. (1997) Robust frequency and timing synchronization for OFDM. IEEE Transactions on Communications 45(12): 1613–1621

    Article  Google Scholar 

  12. Bang K., Cho N., Cho J., Jun H., Kim K., Park H., Hong D. (2001) A coarse frequency offset estimation in an OFDM system using the concept of the coherence phase bandwidth. IEEE Transactions on Communications 49(8): 1320–1324

    Article  MATH  Google Scholar 

  13. Nogami, H., & Nagashima, T. (1995). A frequency and timing period acquisition technique for OFDM systems. PIMRC ’95, (pp. 1010–1015). Toronto.

  14. Morelli M., D’Andrea A.N., Mengali U. (2000) Frequency ambiguity resolution in OFDM systems. IEEE Communications Letters 4(4): 134–136

    Article  Google Scholar 

  15. Kim Y.H., Song I., Yoon S., Park S.R. (2001) An efficient frequency offset estimator for OFDM systems and its performance characteristics. IEEE Transactions on Vehicular Technology 50(5): 1307–1312

    Article  Google Scholar 

  16. Kay, S. M. (1998). Fundamentals of statistical signal processing, detection theory, (Vol. II). Prentice Hall.

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Feng Yang.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Yang, F., Zhang, Z. & Chen, Y. Maximum-Likelihood Estimator for Coarse Carrier Frequency Offset Estimation in OFDM Systems. Wireless Pers Commun 49, 55–66 (2009). https://doi.org/10.1007/s11277-008-9555-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11277-008-9555-5

Keywords

Navigation