Frequency-domain blind equalization method (T/2FF-CMA) based on T/2 fraction space

A fractional interval, blind equalization technology, applied in the field of blind equalization in the frequency domain, can solve the problems of slow convergence speed and large steady-state error, and achieve the effect of reducing the amount of calculation, reducing spectral aliasing, and ensuring real-time performance.

Inactive Publication Date: 2013-04-03
NANJING UNIV OF INFORMATION SCI & TECH
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  • Claims
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AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is aimed at the shortcomings of the traditional baud interval blind equalization method (BSE-CMA), which has large steady-state error and slow convergence speed, and uses fractional interval blind equalizer to avoid spectrum aliasing caused by undersampling. In order to effectively reduce the steady-state error of the blind equalizer; use the fast Fourier transform technique (FFT) and the overlap-preserving algorithm to realize the blind equalization method in the frequency domain to improve the convergence performance of the equalizer and reduce the computational complexity , thus inventing the Fractional Interval-Based Blind Frequency-Domain Equalization Method (FF-CMA)

Method used

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  • Frequency-domain blind equalization method (T/2FF-CMA) based on T/2 fraction space
  • Frequency-domain blind equalization method (T/2FF-CMA) based on T/2 fraction space
  • Frequency-domain blind equalization method (T/2FF-CMA) based on T/2 fraction space

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Embodiment 1

[0053] [Example 1] The transmitted signal is 4QAM; the variance is 1, and the signal-to-noise ratio is 20dB; the weight length of the equalizer is 12 and the center tap is initialized; μ TF-CMA =0.002,μ FF-CMA =0.004,μ T / 2FF-CMA =0.004; 5000 Monte Carlo simulation results, such as image 3 shown.

[0054] image 3 (a) shows that the convergence speed of the inventive method T / 2FF-CMA has improved 450 steps and 300 steps respectively than TF-CMA and FB-CMA; Its steady-state error has reduced 5dB respectively than TB-CMA and TF-CMA and 3dB. image 3 (b) to (e) show that the constellation diagrams output by T / 2FF-CMA of the method of the present invention are clearer and more concentrated than those output by TF-CMA and TB-CMA.

Embodiment 2

[0055] [Example 2] The transmitted signal is 4PSK; the variance is 1, and the signal-to-noise ratio is 20dB; the weight length of the equalizer is 12 and the center tap is initialized; μ TF-CMA =0.006,μ FF-CMA =0.006,μ T / 2FF-CMA =0.008; 5000 Monte Carlo simulation results, such as Figure 4 shown.

[0056] Figure 4 (a) shows that the convergence speed of the inventive method T / 2FF-CMA has improved 450 steps and 200 steps respectively than TF-CMA and TB-CMA; Its steady-state error has reduced 3dB than TF-CMA and TB-CMA. Figure 4 (b) to (e) show that the constellation diagrams output by T / 2FF-CMA of the method of the present invention are clearer and more concentrated than those output by TF-CMA and TB-CMA.

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Abstract

The invention discloses a frequency-domain blind equalization method (T / 2FF-CMA) based on T / 2 fraction space, which aims at the shortages of the large steady state error and the low convergence speed of a baud spaced blind equalization method, avoids frequency spectrum aliasing due to sampling lacking by a fraction spaced blind equalizer so as to effectively reduce the steady state error of the blind equalizer, and realizes the frequency-domain blind equalization method (T / 2FF-CMA) by a fast Fourier transform technique (FFT) and an overlay retaining method so as to improve the convergence property of the blind equalizer and reduce the computing complexity. The frequency-domain blind equalization method (T / 2 FF-CMA) has small steady state error, high convergence speed and low computing complexity; and in addition, a water sound channel embodiment shows that the frequency-domain blind equalization method (T / 2FF-CMA) has superior property compared with a baud spaced time-domain blind equalization method (TB-CMA) and a fraction spaced time-domain blind equalization method (TF-CMA).

Description

technical field [0001] The invention relates to a frequency-domain blind equalization method based on T / 2 fractional intervals, and belongs to the technical field of blind equalization methods for overcoming inter-symbol interference (Inter-Symbol Interference, ISI) caused by multipath fading of underwater acoustic channels. Background technique [0002] In the underwater acoustic communication system, due to the influence of multipath fading and channel distortion, serious intersymbol interference occurs at the receiving end, which reduces the quality of information transmission. The most effective way to overcome intersymbol interference is to use equalization technology at the receiving end. The traditional equalization technology uses the training sequence sent by the transmitter to assist in channel estimation and equalization, which wastes limited bandwidth resources. Blind equalization technology has become a current research hotspot because it does not need to send ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L25/03
Inventor 郭业才林仁刚
Owner NANJING UNIV OF INFORMATION SCI & TECH
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