Orthogonal wavelet transform and time diversity technique fused blind equalizing method

A technology of time diversity and orthogonal wavelet, which is applied in the direction of equalizer, error prevention/detection through diversity reception, multi-carrier system, etc. It can solve problems such as large mean square error and slow convergence speed

Inactive Publication Date: 2009-07-08
NANJING UNIV OF INFORMATION SCI & TECH
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Problems solved by technology

But the convergence speed is slow and the mean square error is large

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  • Orthogonal wavelet transform and time diversity technique fused blind equalizing method
  • Orthogonal wavelet transform and time diversity technique fused blind equalizing method
  • Orthogonal wavelet transform and time diversity technique fused blind equalizing method

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[0031] Such as figure 1shown. Time diversity refers to repeatedly sending the same signal at a time interval exceeding the channel coherence time, so that the receiving end receives multiple signals with independent fading environments, and then combines them in an appropriate way, thereby improving the signal-to-noise ratio of the receiving end and reducing the bit error rate. . It has a D-fold time-diversity blind equalizer structure. In the time-diversity blind equalizer, each branch is composed of the same channel and different sub-equalizers. The output signals of each branch are then combined by a combiner. In the combination technology, although the performance of equal-gain combination is not as good as that of maximum ratio combination, it is the easiest to implement.

[0032] The constant modulus algorithm (HCMA) based on the hyperbolic tangent function has better performance than the traditional constant modulus algorithm. After introducing time diversity into the...

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Abstract

The invention discloses a blind equalization method with the integration of orthogonal wavelet transformation and time diversity technique. Integrated with time diversity technique, wavelet transformation technique, phase-lock ring technique and decision-directed (DD) algorithm, the blind equalization method can reduce the influences of multipath effect by using time diversity, can overcome the disadvantages of asymmetry of constant modulus error function by using a hyperbolic tangent error function, can lower the self-correlativity of input signals of a blind equalizer by using orthogonal wavelet transformation to improve the convergence speed, can reduce stable error by using DD algorithm, and can correct phase rotation by using digital phase-lock ring technique. The method has the advantages of high convergence speed and less mean square error, and can effectively suppress phase rotation.

Description

technical field [0001] The invention relates to a time diversity blind equalization method, in particular to a blind equalization method combining orthogonal wavelet transform and time diversity technology. Background technique [0002] In underwater acoustic communication, due to the existence of multipath fading and channel distortion, serious inter-symbol interference (Inter-Symbol Interference, ISI) will be generated at the receiving end, which reduces the information transmission rate and reliability. Blind equalization technology saves bandwidth because it does not require training sequences, so it is more suitable for underwater acoustic channels with limited bandwidth. However, the traditional blind equalization technology does not solve the impact of channel multipath fading well. Diversity technology is one of the effective ways to overcome multipath fading. Therefore, applying diversity technology to blind equalization will greatly improve the communication qualit...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L25/03H04L27/01H04L27/38H04L1/06
Inventor 郭业才丁雪洁
Owner NANJING UNIV OF INFORMATION SCI & TECH
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