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A method and circuit for detecting carrier frequency deviation and sampling frequency deviation

A technology of carrier frequency offset and sampling frequency offset, which is applied in the field of OFDM modulation system, can solve the problems of large error and slow convergence speed, and achieve the effect of reducing difficulty and complexity

Active Publication Date: 2008-08-06
扬智电子科技(中国)有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] This existing detection method is actually easy to implement, but the error is large and the convergence speed is slow when the signal noise is relatively small or the frequency selective fading is serious

Method used

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  • A method and circuit for detecting carrier frequency deviation and sampling frequency deviation
  • A method and circuit for detecting carrier frequency deviation and sampling frequency deviation
  • A method and circuit for detecting carrier frequency deviation and sampling frequency deviation

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Embodiment Construction

[0021] According to an embodiment of the present invention, first, FFT processing is performed on the received signal R of the receiving end in the OFDM system to obtain the information of the received signal R in the frequency domain, as follows:

[0022]

[0023] c(l, k), H(l, k), f, ζ, n(l,k) respectively represent transmitted symbols, channel frequency response, carrier frequency offset, sampling frequency offset, carrier initial phase deviation, phase noise and Gaussian white noise caused by the receiving end. Then, perform correlation operations on two adjacent symbols in the frequency domain information of each subcarrier with the pilot signal to obtain the relevant information of each pilot signal, as shown in the following formula:

[0024]

[0025] In order to simplify the calculation, only the phase part of the relevant information of each pilot signal is taken for subsequent detection, and the following is obtained:

[0026] θ ( ...

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PUM

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Abstract

The invention provides a method for detecting the carrier frequency shift and the sampling frequency shift in an OFDM system and a circuit thereof. The method for detecting the carrier frequency shift and the sampling frequency shift in the OFDM system comprises the following steps that: related calculations are done on two adjacent code elements on each sub-carrier with a steering signal in order to obtain the related information of each steering signal; the channel frequency response energy of each carrier and each channel serial number are adopted to obtain the information of each channel; the related information of each steering signal, the channel frequency response energy of each sub-carrier and each channel serial number are adopted to obtain the related information of each steering channel; the related information of each steering channel and the information of each channel are adopted to obtain the related detection information of the frequency shift and the sampling shift. The invention combines all the information and the arithmetic elements necessary to the application, thereby decreasing the complexity of the circuit. The method of splitting operation can be also adopted to decrease the difficulty of the multiply operation and the division operation and to keep the accuracy of information.

Description

Technical field [0001] The present invention relates to an Orthogonal Frequency Division Multiplex (OFDM) system, and particularly relates to a method and circuit for detecting carrier frequency offset and sampling frequency offset in an OFDM system. Background technique [0002] At present, OFDM modulation technology is widely used in digital broadcasting systems. The main advantage of OFDM modulation technology is its ability to resist multipath fading, but it is very sensitive to carrier frequency offset or sampling frequency offset. Especially when the fundamental frequency signal is modulated by high-order quadrature amplitude modulation (QAM, Quadrature Amplitude Modulation), taking 64QAM as an example, the tolerable carrier frequency deviation is about one thousandth. Therefore, detecting carrier frequency offset or sampling frequency offset is an important issue in OFDM systems. [0003] Generally, the method of detecting carrier frequency offset or sampling frequency off...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04B1/707
Inventor 李琳
Owner 扬智电子科技(中国)有限公司
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