a novel time and frequency synchronization scheme for ofdm systems
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
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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
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Outline
Introduction System Description Proposed Scheme Simulation Results Conclusion
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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.
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System Description
The nth received sample has the standard form:
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System Description
Schmidl’s Method
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System Description
Minn’s Method
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System Description
Park’s Method
D is designed to be symmetric with the conjugate of C.
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Proposed Scheme
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
A. Proposed Training Symbol
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Proposed Scheme
The form of the designed training symbol
in time domain is as follows:
B. Time Synchronization
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Proposed Scheme
Comparison of the timing metric of estimators
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Proposed Scheme
The fractional frequency offset can be estimated by ML estimator using the redundant information contained within the cyclic prefix:
C. Frequency Synchronization
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Proposed Scheme
Coarse estimate by minimum energy detection
Fine estimate by partial correlation
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Proposed Scheme
COMPARISON OF THE FREQUENCY OFFSET ESTIMATION RANGE
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Simulation Results
Channel impulse response of the multipath fading channel
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Simulation Results
MSE of the timing offset estimation in multipath fading channels
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Simulation Results
Mean of the frequency offset estimation in multipath fading channels
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Simulation Results
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Simulation Results
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Simulation Results
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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.
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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
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Thanks for your attention