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OFDM channel estimating method based on wavelet unbiased risk threshold value noise elimination

A threshold denoising and channel estimation technology, applied in the baseband system components, multi-frequency code system, etc., can solve the problem that the LS method is easily affected by noise, and achieve superior performance, strong robustness, and good estimation performance.

Inactive Publication Date: 2008-07-23
XIDIAN UNIV
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Problems solved by technology

[0006] The purpose of the present invention is: aim at the deficiency of above-mentioned OFDM channel estimation method, propose a kind of OFDM channel estimation method based on wavelet unbiased risk threshold value denoising, thus effectively solve the problem that LS method is easily affected by noise, simultaneously this method It does not need to know any prior information about the channel, nor is it affected by timing errors and channel environment

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  • OFDM channel estimating method based on wavelet unbiased risk threshold value noise elimination
  • OFDM channel estimating method based on wavelet unbiased risk threshold value noise elimination
  • OFDM channel estimating method based on wavelet unbiased risk threshold value noise elimination

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[0032] With reference to Fig. 1, it is the realization flowchart of the present invention, can find out from the figure that the concrete realization steps of the present invention are as follows:

[0033] (1), according to the basic principle of the OFDM system, use the LS estimation method to estimate the channel frequency domain response H(k) containing noise, where 1≤k≤N, k is the subcarrier sequence number, and N is the total number of subcarriers.

[0034] (2) For the obtained channel frequency domain response H(k), do N-point inverse discrete Fourier transform to obtain the noise-containing channel time domain impulse response h(n), 1≤n≤N, h(n)= IDFT(H(k))

[0035] (3) Perform discrete wavelet transform on the time-domain impulse response h(n) of the channel to obtain wavelet coefficients, and form a wavelet coefficient matrix by all wavelet coefficients d ^ = ( d ...

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Abstract

The invention discloses an OFDM channel estimation method for de-noising which is based on wavelet unbiased risk threshold value, which relates to the technical field of communication, the purpose of the invention is that the problem that an LS method is easy to be influenced by noise under the condition without channel information is effectively solved. The realizing process of the method comprises first, obtaining channel frequency response which contains noise according to the LS channel estimation method which is on the basis of an OFDM system which is based on pilot frequency, second, doing inverse discrete Fourier transform for the channel frequency response which is obtained and to get channel time-domain impulse response which contains noise, third, de-noising the channel time-domain impulse response the method for de-noising which is based on wavelet unbiased risk threshold value, and getting channel time-domain impulse response after de-noising, fourth, doing inverse discrete Fourier transform for the channel time-domain impulse response after de-noising, and getting frequency domain response of channel, and compensating the received signals by the channel time-domain impulse response after de-noising. The method can be used in OFDM channel estimation techniques under various multi-path channels.

Description

technical field [0001] The invention belongs to the field of communication technology, and relates to signal processing technology, in particular to an orthogonal frequency division multiplexing OFDM channel estimation method based on wavelet unbiased risk threshold SURE denoising, which can be used in various multipath channel environments in channel estimation techniques. Background technique [0002] Since entering the 21st century, wireless communication technology is developing at an unprecedented speed. In order to support higher information transmission rate and higher user mobile speed, a new transmission technology with higher spectral efficiency and stronger anti-multipath interference capability must be adopted in the next generation of wireless communication. Among the various wireless solutions that can provide high-speed transmission at present, multi-carrier modulation technology represented by Orthogonal Frequency Division Multiplexing (OFDM) is one of the m...

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Application Information

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IPC IPC(8): H04L25/02H04L27/26
Inventor 赵林靖王雪李建东沈若骋薛晓洁程建波
Owner XIDIAN UNIV
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