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Time-frequency expanding anti-jamming method, equipment and system based on lapped transformation algorithm

A time-frequency spreading and overlapping transform technology is applied in the fields of modulation devices, demodulation devices, time-frequency spreading anti-jamming methods and systems, and can solve problems such as affecting the effect of interference suppression, unfavorable for separating interference and useful signals, polluting sub-bands, etc.

Inactive Publication Date: 2011-03-16
PEKING UNIV
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Problems solved by technology

Spectrum leakage makes the interference diffuse in the transform domain, pollutes all sub-bands, is not conducive to separating interference and useful signals, and affects the effect of interference suppression

Method used

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  • Time-frequency expanding anti-jamming method, equipment and system based on lapped transformation algorithm
  • Time-frequency expanding anti-jamming method, equipment and system based on lapped transformation algorithm
  • Time-frequency expanding anti-jamming method, equipment and system based on lapped transformation algorithm

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Embodiment Construction

[0026] In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] The present invention applies MLT (Modulated Lapped Transform) to OFDM modulation and demodulation, that is, IMLT is used to modulate data onto subcarriers at the sending end, and MLT is used to demodulate data at the receiving end. Since the filter bank formed by the basis functions of the MLT transform has a better ability to suppress side lobes than the DFT (Discrete Fourier Transform, discrete Fourier transform) transform, and the present invention uses cognitive radio for frequency scheduling at the same time, therefore, it can be very good It solves the problem of leakage of narrowband interference energy in the whole frequency band.

[0028] refer to figure 1 , figure 1 It is a flow chart of the steps of an embodim...

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Abstract

The invention discloses a time-frequency expanding anti-jamming method, equipment and system based on a lapped transformation algorithm. The method comprises a spread spectrum code chip obtaining step, a frequency domain spread spectrum step, a modulation step in which inverse overlapping transformation modulation is utilized and a demodulation step in which overlapping transformation demodulation is utilized. The invention adopts an EFT-OFDM system of lapped transformation modulation, avoids the narrow-band interference from spreading on a subcarrier caused by traditional inverse discrete Fourier transform (IDFT) or discrete Fourier transform (DFT) through frequency schedule by a cognitive radio technology, thus the anti-jamming capability of the system is improved.

Description

technical field [0001] The present invention relates to the existing ETF-OFDM (Expanded Timeand Frequency-Orthogonal Frequency Division Multiplexing) technology in the field of satellite communication, in particular to a time-frequency expansion anti-jamming method and system, a modulation device, Demodulation device. Background technique [0002] Multi-carrier CDMA (MC-CDMA) combines CDMA and OFDM technologies, and different chips corresponding to the same data symbol are transmitted in parallel on different subcarriers of an OFDM symbol, which can take advantage of the anti-multipath interference and High spectral efficiency features to improve CDMA performance. [0003] ETF-OFDM (Expanded Time and Frequency OFDM) system is a two-dimensional orthogonal spread spectrum system based on OFDM time domain and frequency domain expansion, which performs direct sequence spread spectrum in time domain and frequency domain through different spreading codes , so that each original ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04B1/707
Inventor 尚勇封晓弢
Owner PEKING UNIV
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