OFDM demodulator
AssigneeNEC Corporation
InventorsTakeshi Yamamoto, Kazuhiro Okanoue, Tomoki Osawa
Life of this patent
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Abstract
In an OFDM demodulator, in order to stably perform a timing reproducing process with a simple configuration, a complex correlation circuit correlates sampled and quantized digital complex baseband signals outputted from A/D converters and a pattern of a preamble for timing/carrier frequency synchronization of a short symbol prestored in a reference signal storing circuit and outputs the correlation result. The correlation result is supplied to a timing detecting circuit and the timing of the short symbol is detected.
Claims2
An OFDM demodulator for demodulating an orthogonal frequency division multiplexing (OFDM) modulated burst signal, comprising:
- a quasi-synchronous detector for converting the OFDM modulated bust signal into two complex baseband signals by quasi-synchronous detection;
- a carrier frequency estimating circuit for receiving the complex baseband signals, estimating a carrier frequency, and compensating a carrier frequency error;
- a symbol timing estimating circuit for controlling the width of a detection window on the basis of a result of correlation between a preamble signal in the complex baseband signal and a prestored pattern signal and reproducing a timing of the burst signal;
- a symbol synchronization processing circuit for establishing symbol synchronization on the basis of an output of the symbol timing estimating means with respect to the complex baseband signal in which the carrier frequency error has been compensated;
- an FFT for performing Fourier transform on an output of the symbol synchronization processing circuit to thereby divide the output into signals of respective subcarriers;
- and
- a subcarrier demodulator for demodulating an output of the FFT every subcarrier.
Dependencies are inferred from the claim text.