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A Novel Time and Frequency Synchronization Scheme for OFDM Systems

A Novel Time and Frequency Synchronization Scheme for OFDM Systems. Ching-Yu Wang Graduate Institute of Communication Engineering National Chi Nan University 12 / 25 / 2008. Outline. Introduction System Description Proposed Scheme Simulation Results Conclusion. Introduction.

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A Novel Time and Frequency Synchronization Scheme for OFDM Systems

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  1. A Novel Time and Frequency Synchronization Scheme for OFDM Systems Ching-Yu Wang Graduate Institute of Communication Engineering National Chi Nan University 12 / 25 / 2008

  2. Outline • Introduction • System Description • Proposed Scheme • Simulation Results • Conclusion

  3. Introduction • Schmidl’s method has a plateau which causes a large variance in the timing offset estimation. • Minn’s method performs well, but its estimation variance is quite large in ISI channels. • Park produces an even sharper timing metric than Schmidl’s and Minn’s, but its timing metric has two large sidelobes which will affect the timing performance.

  4. System Description The nth received sample has the standard form:

  5. System Description • Schmidl’s Method

  6. System Description • Minn’s Method

  7. System Description • Park’s Method D is designed to be symmetric with the conjugate of C.

  8. Proposed Scheme A. Proposed Training Symbol The samples of the new training symbol in frequency domain are designed to be of the form: and the corresponding time-domain complex baseband training symbol samples are

  9. Proposed Scheme B. Time Synchronization The form of the designed training symbol in time domain is as follows:

  10. Proposed Scheme Comparison of the timing metric of estimators

  11. Proposed Scheme C. Frequency Synchronization The fractional frequency offset can be estimated by ML estimator using the redundant information contained within the cyclic prefix:

  12. Proposed Scheme • Coarse estimate by minimum energy detection • Fine estimate by partial correlation

  13. Proposed Scheme COMPARISON OF THE FREQUENCY OFFSET ESTIMATION RANGE

  14. Simulation Results Channel impulse response of the multipath fading channel

  15. Simulation Results MSE of the timing offset estimation in multipath fading channels

  16. Simulation Results Mean of the frequency offset estimation in multipath fading channels

  17. Simulation Results

  18. Simulation Results

  19. Simulation Results

  20. Conclusion • A new training symbol is designed and a simple time and frequency synchronization scheme is proposed in this paper. • The scheme gives very accurate estimates of symbol timing and carrier frequency offset and provides a very wide acquisition range for the carrier frequency offset.

  21. References G. Yi, L. Gang, G. Jianhua, “A novel time and frequency synchronization scheme for OFDM systems,” IEEE Transactions on Consumer Electronics, Vol. 54, pp.321 - 325, May. 2008

  22. Thanks for your attention

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