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Estimate method for frequency deviation of OFDM signal based on the fast Fourier transform

A technology of frequency offset estimation and Fourier transform, applied in the field of OFDM signal frequency offset estimation, which can solve the problems of limited frequency range, sub-channel interference, demodulation result error and so on.

Inactive Publication Date: 2007-07-11
INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI
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Problems solved by technology

Respectively refer to the integer part and the fractional part of the subcarrier spacing. The integer part only shifts the information symbols on the subchannel and does not destroy the orthogonality between the subcarriers, but it causes the entire demodulation result to be completely wrong, and the system error The code rate is almost 0.5; the fractional part will cause sub-channel interference, destroy the orthogonality between sub-carriers, and lead to a decrease in the system bit error rate
[0006] So far, a variety of OFDM frequency offset estimation methods have been proposed, most of which use data correlation at the receiver to estimate the frequency offset, but the frequency range estimated by these methods is very limited and requires independent computing hardware circuits

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  • Estimate method for frequency deviation of OFDM signal based on the fast Fourier transform

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[0019] Please refer to Fig. 1, a method for estimating the frequency offset of OFDM signals based on fast Fourier transform in the present invention, which is mainly used in wireless local area network systems, including: rough frequency offset estimation and precise frequency offset shift estimation; rough frequency offset estimation adopts an idea based on fast Fourier transform, using the existing fast Fourier hardware at the receiving end, can reduce the final chip area, and is characterized in that it includes the following steps:

[0020] 1) After the time-synchronized data sequence received by the baseband of the wireless local area network system is properly transformed, the transformed data is sent to the fast Fourier transform; the time-synchronized data sequence received by the baseband of the wireless local area network system and The locally stored data is convolved, and the convolved data sequence is input to the fast Fourier transform module. For the wireless LAN...

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Abstract

This invention relates to one cross multiplex signal frequency bias estimation method based on rapid Fourier exchange in wireless local zone system, which comprises the following steps: a, wireless local network system base band receives time simultaneous data sequence through proper exchange and sending the exchange data into Fourier exchange; b, researching the exchanged data from Fourier to get rough bias estimation of frequency to compensate data; c, processing accurate bias frequency estimating on compensated data.

Description

technical field [0001] The present invention provides a method for estimating the frequency offset of an Orthogonal Frequency Division Multiplexing (OFDM) signal, in particular to a method for estimating the frequency offset of an Orthogonal Frequency Division Multiplexing (OFDM) signal based on Fast Fourier Transform (FFT). Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM) is a high-speed broadband transmission technology in a wireless environment. In view of the frequency selective response of wireless channels, the main idea of ​​OFDM technology is to divide a given channel into multiple sub-channels in the frequency domain, use a sub-carrier for modulation on each sub-channel, and transmit sub-carrier sequences in parallel, so The frequency response of the sub-channel is relatively flat, and the signal bandwidth is smaller than the relevant bandwidth of the channel, which greatly reduces the inter-symbol interference; the sub-carrier spectru...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26
Inventor 方治石寅
Owner INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI
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