Walsh码软扩频信号降噪算法

doi:10.3969/j.issn.1001-506X.2020.04.06

系统工程与电子技术 ›› 2020, Vol. 42 ›› Issue (4): 773-780.doi: 10.3969/j.issn.1001-506X.2020.04.06

Walsh码软扩频信号降噪算法

张丹娜(), 钱锋(), 冯辉(), 闻年成()

国防科技大学电子对抗学院, 安徽合肥 230037

收稿日期:2019-07-08 出版日期:2020-03-28 发布日期:2020-03-28
作者简介:张丹娜(1994-),女,硕士研究生,主要研究方向为软扩频信号盲解扩。E-mail:elaine_1205@outlook.com|钱锋(1981-),男,讲师,博士,主要研究方向为通信信号处理,非线性理论与应用。E-mail:qian_fn@126.com|冯辉(1978-),男,讲师,博士,主要研究方向为信号分析与识别。E-mail:823706306@qq.com|闻年成(1987-),男,讲师,硕士,主要研究方向为信息对抗。E-mail:963301482@qq.com
基金资助:
国家自然科学基金(61671453);国防科技大学自然科学基金(ZK18-03-19)

Noise reduction algorithm of Walsh code soft spread spectrum signal

Danna ZHAGN(), Feng QIAN(), Hui FENG(), Niancheng WEN()

College of Electronic Countermeasures, National University of Defense Technology, Hefei 230037, China

Received:2019-07-08 Online:2020-03-28 Published:2020-03-28
Supported by:
国家自然科学基金(61671453);国防科技大学自然科学基金(ZK18-03-19)

摘要/Abstract

摘要：

针对低信噪比(signal-to-noise ratio, SNR)条件下, Walsh码软扩频信号盲解扩以及多址信号盲分离难以实现的问题,提出一种Walsh码软扩频信号降噪算法。首先,采用经验模态分解(empirical mode decomposition, EMD)算法将Walsh码软扩频信号分解为有限个本征模态函数(intrinsic mode function, IMF),分界点位置可通过Walsh码软扩频信号和噪声的IMF自相关函数收敛速度的差异进行判断。然后,采用小波软阈值滤波算法处理分界点之前的IMF。最后,利用处理后的低阶IMF和分界点后的IMF重构Walsh码软扩频信号,减少由于降噪造成的信号损失。仿真结果表明,在一定低SNR范围内,降噪算法以较低误码率(bit error rate, BER)实现解调,信号损失较少。

关键词: Walsh码, 软扩频信号, 降噪, 经验模态分解算法

Abstract:

In order to solve the problem of soft spread spectrum signals with low signal-to-noise ratio (SNR) so that it is difficult to realize blind dispreading and blind separation, an improved soft spread spectrum noise reduction algorithm is presented. This algorithm uses the empirical mode decomposition (EMD) algorithm to realize the soft spread spectrum signal denoising, judges the location of the dividing point according to the difference between the soft spread spectrum signal and the noise auto-correlation function and applies wavelet threshold filtering to the intrinsic mode function (IMF) component before the dividing point. Finally, the soft spread spectrum signals are constructed by processed low order IMF components and IMF components after the dividing point. The algorithm makes use of lower IMF components and judges the location of the dividing point according to the auto-correlation characteristics of the IMF component to reduce the signal loss caused by noise reduction. Simulation results show that within a certain SNR range, the denoising algorithm achieves demodulation with low bit error rate (BER) and less signal loss.

Key words: Walsh code, soft spread spectrum signal, noise reduction, empirical mode decomposition algorithm

中图分类号:

TN911.7

张丹娜, 钱锋, 冯辉, 闻年成. Walsh码软扩频信号降噪算法[J]. 系统工程与电子技术, 2020, 42(4): 773-780.

Danna ZHAGN, Feng QIAN, Hui FENG, Niancheng WEN. Noise reduction algorithm of Walsh code soft spread spectrum signal[J]. Systems Engineering and Electronics, 2020, 42(4): 773-780.

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Walsh码软扩频信号降噪算法

Noise reduction algorithm of Walsh code soft spread spectrum signal

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