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US 8,275,052 B2Granted
FFT carrier frequency offset estimation for OFDM signal
AssigneeNokia Corporation
InventorsLudwig Schwoerer, Andre Kaufmann
Life of this patent
Estimating the term…
Abstract
There is being disclosed an OFDM signal receiver for detecting carrier frequency offset. When FFT transform of the signal is processed in the receiver, an estimator applies the spectrum shape of the FFT transform for estimating the carrier frequency offset.
Claims23
An apparatus comprising:
- a Fourier transform module configured to obtain a fast Fourier transform transformation of an orthogonal frequency division multiplexing signal comprising guard bands, and
- an estimator configured to estimate a carrier frequency offset for the orthogonal frequency division multiplexing signal by determining a power profile of the fast Fourier transform transformed orthogonal frequency division multiplexing signal comprising computing sliding window power sums, each over N consecutive sub-carriers, and associating a sub-carrier with the guard-band if the sliding window power sum corresponding to the sub-carrier is below a certain percentage of overall received power of the signal.
A method for receiving an orthogonal frequency division multiplexing signal comprising guard bands, the method comprising:
- obtaining a fast Fourier transform transformation of an orthogonal frequency division multiplexing signal;
- and
- estimating a carrier frequency offset for the orthogonal frequency division multiplexing signal by determining a power profile of the fast Fourier transform transformed orthogonal frequency division multiplexing signal comprising computing sliding window power sums, each over N consecutive sub-carriers, and associating a sub-carrier with the guard-band if the sliding window power sum corresponding to the sub-carrier is below a certain percentage of overall received power of the signal.
An apparatus comprising:
- means for obtaining a fast Fourier transform transformation of an orthogonal frequency division multiplexing signal, and
- means for estimating a carrier frequency offset for the orthogonal frequency division multiplexing signal by determining a power profile of the fast Fourier transform transformed orthogonal frequency division multiplexing signal comprising computing sliding window power sums, each over N consecutive sub-carriers, and associating a sub-carrier with the guard-band if the sliding window power sum corresponding to the sub-carrier is below a certain percentage of overall received power of the signal.
Dependencies are inferred from the claim text.