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直接序列扩频通信中窄带干扰抑制的奇异值分解方法 总被引:5,自引:2,他引:3
在很强的单音干扰存在时,传统的线性预测滤波方法不能达到很好的抗干扰性能.该文提出了一种用奇异值分解方法(SVD)来抑制扩频通信中的单音干扰的问题,建立了利用SVD技术抑制直接序列扩频通信(DSSS)中的窄带干扰的系统模型.并与传统的双边LMS滤波器进行了误码率比较.仿真表明,SVD方法对干扰有很强的抑制能力,当BER=10-2时,SVD方法的增益要高于LMS方法3dB.而且同传统的LMS算法相比,SVD方法避免了算法收敛的问题. 相似文献
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雷电等瞬态干扰严重影响了高频雷达的工作性能,必须加以抑制。本文提出了基于矩阵奇异值分解的高频雷达瞬态干扰抑制方法。该方法将高频雷达回波信号分段构造成矩阵并进行奇异值分解,首先根据矩阵有效秩的大小判断雷达回波中是否存在瞬态干扰,然后利用奇异值分解的正交性实现雷达回波的正交分解,使瞬态干扰分离出来,以利于检测,最后通过建立线性预测的全极点AR模型对瞬态干扰位置处的回波信号予以恢复。实测数据处理结果表明本文方法是有效的。 相似文献
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基于矩阵奇异值分解的高频雷达瞬态干扰抑制 总被引:5,自引:0,他引:5
雷电等瞬态干扰严重影响了高频雷达的工作性能,必须加以抑制。该文提出了基于矩阵奇异值分解的高频雷达瞬态干扰抑制方法。该方法将高频雷达回波信号分段构造成矩阵并进行奇异值分解,首先根据矩阵有效秩的大小判断雷达回波中是否存在瞬态干扰,然后利用奇异值分解的正交性实现雷达回波的正交分解,使瞬态干扰分离出来,以利于检测,最后通过建立线性预测的全极点自回归模型对瞬态干扰位置处的回波信号予以恢复。实测数据处理结果表明该方法是有效的。 相似文献
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无线通信中的抗干扰技术对通信的稳定性和安全性都具有重要意义,干扰识别作为抗干扰技术的重要环节一直是研究的热点。该文提出一种基于奇异值分解与神经网络的干扰识别方法,该方法只计算信号矩阵的奇异值即完成特征提取,与传统方法相比节省了多个谱特性的计算量。仿真结果表明:基于奇异值分解与神经网络的干扰识别方法与传统方法相比在干信比为0 dB左右的条件下识别准确率有10%~25%的提高。 相似文献
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基于奇异值分解的图像去噪 总被引:3,自引:0,他引:3
提出了利用奇异值分解去除图像噪声的方法。从矩阵的角度出发,通过对图像矩阵进行奇异值分解,将包含图像信息的矩阵分解到一系列奇异值和奇异值矢量对应的子空间中,然后通过有效奇异值重构图像矩阵达到去噪目的。试验利用MATLAB通过对MRI(核磁共振)医学图像进行去噪处理,验证了奇异值分解的去噪效果,并且通过对多幅图像的试验结果进行分析,得到了去噪重构图像时所需有效奇异值数目的统计值。 相似文献
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随着计算机和网络技术的飞速发展,数字图像、音频和视频产品愈来愈需要一种有效的版权保护方法,另外通信系统在网络环境下的信息安全问题也日益显露出来.数字图像水印技术为上述问题提供了一个潜在的解决方案.所谓水印技术就是将数字、序列号、文字、图像标志等版权信息嵌入到多媒体数据中,以起到版权保护、秘密通信、数据文件的真伪鉴别和产品标志等作用.本文提出了一种新的基于奇异值分解的数字水印算法并且对该方法的理论基础给出分析.实验结果表明这种方法要比目前提出的流行算法鲁棒. 相似文献
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本文综述了有关修正的奇异值分解的算法和Systolic阵列实现的一些最新结果,讨论了普通奇异值分解(OSVD)、积奇异值分解(PSVD)和商奇异值分解(QSVD)。修正算法是指交叉使用QR更新和三角约化Jacobi SVD算法,在其每步计算中采用有限次操作(O(n~2)),由前一次近似分解结果计算新的近似分解。这些算法与指数加权相结合,显然对跟踪问题极为适用,而且只要对熟知的矩阵何量积、QR更新和SVD的Systo1ic阵列稍加修改,就能把它们完美地映射到Systolic阵列上去。 相似文献
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SVD-based MIMO Precoding and Equalization Schemes for Realistic Channel Knowledge: Design Criteria and Performance Evaluation 总被引:1,自引:0,他引:1
Multiple-input multiple-output (MIMO) based communication systems with precoding, bit-loading and equalization procedures
are considered in this paper. Applications of precoding schemes, which are based on Singular Value Decomposition (SVD) of
the channel matrix H assume almost always ideal channel knowledge at the transmitter and/or receiver site. This paper investigates an SVD based
MIMO approach considering non ideal radio channel estimation results. In any case the MIMO channel matrix H is decomposed into Eigenmodes. In case of an ideal radio channel knowledge the SVD based precoding procedure, which is applied
at the transmitter site, is going to consider all possible Eigenmodes which results in a perfect separation of all signals
at the receive antenna output and into a minimum bit-error-rate (BER). It will be shown in this paper that in case of non
ideal channel knowledge and a limited accuracy in the channel matrix H estimation a reduced number of Eigenmodes in the precoding process will become an optimum and will lead into an increased
BER performance.
相似文献
Hermann RohlingEmail: |
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时间交替模数转换器(Time-Interleaved ADC,TIADC)通道间的采样时间相对误差严重影响了系统的无杂散动态范围(Spurious-Free Dynamic Range,SFDR).为校正采样时间相对误差,本文基于TIADC输出与模拟输入信号之间的频域关系,提出一种通过消除输出信号中的误差来校准TIADC的算法.该算法在对输出信号频率表达式进行泰勒近似的基础上构建理想输出信号,并采用最小均方差(LMS)算法来估算时间误差,旨在降低硬件设计的复杂度,提高误差校正的精确度.仿真和验证结果表明该校正算法很容易扩展到多通道,并且可以将输出频谱的SFDR提高约47dB. 相似文献
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自适应最小二乘格型算法在天线阵列中的应用 总被引:1,自引:0,他引:1
在天线阵列中对天线阵列信号分析的算法有LMS和RLS等,主要介绍了自适应最小二乘格型算法LSL对天线信号进行分析,并对算法过程展开介绍。 相似文献
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Guan Gui Abolfazl Mehbodniya Fumiyuki Adachi 《Wireless Communications and Mobile Computing》2015,15(12):1649-1658
Standard least mean square/fourth (LMS/F) is a classical adaptive algorithm that combined the advantages of both least mean square (LMS) and least mean fourth (LMF). The advantage of LMS is fast convergence speed while its shortcoming is suboptimal solution in low signal‐to‐noise ratio (SNR) environment. On the contrary, the advantage of LMF algorithm is robust in low SNR while its drawback is slow convergence speed in high SNR case. Many finite impulse response systems are modeled as sparse rather than traditionally dense. To take advantage of system sparsity, different sparse LMS algorithms with lp‐LMS and l0‐LMS have been proposed to improve adaptive identification performance. However, sparse LMS algorithms have the same drawback as standard LMS. Different from LMS filter, standard LMS/F filter can achieve better performance. Hence, the aim of this paper is to introduce sparse penalties to the LMS/F algorithm so that it can further improve identification performance. We propose two sparse LMS/F algorithms using two sparse constraints to improve adaptive identification performance. Two experiments are performed to show the effectiveness of the proposed algorithms by computer simulation. In the first experiment, the number of nonzero coefficients is changing, and the proposed algorithms can achieve better mean square deviation performance than sparse LMS algorithms. In the second experiment, the number of nonzero coefficient is fixed, and mean square deviation performance of sparse LMS/F algorithms is still better than that of sparse LMS algorithms. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Normalized least mean square (NLMS) was considered as one of the classical adaptive system identification algorithms. Because most of systems are often modeled as sparse, sparse NLMS algorithm was also applied to improve identification performance by taking the advantage of system sparsity. However, identification performances of NLMS type algorithms cannot achieve high‐identification performance, especially in low signal‐to‐noise ratio regime. It was well known that least mean fourth (LMF) can achieve high‐identification performance by utilizing fourth‐order identification error updating rather than second‐order. However, the main drawback of LMF is its instability and it cannot be applied to adaptive sparse system identifications. In this paper, we propose a stable sparse normalized LMF algorithm to exploit the sparse structure information to improve identification performance. Its stability is shown to be equivalent to sparse NLMS type algorithm. Simulation results show that the proposed normalized LMF algorithm can achieve better identification performance than sparse NLMS one. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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改进的抗窄带干扰非线性预测方法 总被引:1,自引:0,他引:1
为了有效抑制直接序列扩频通信中的窄带干扰,提出了2种改进的非线性预测方法(NLMSN和LNLMSN)。NLMSN是在原非线性预测方法的基础上,针对NLMS算法在强干扰条件下抑制性能不理想的缺点,运用修正LMS Newton算法对其进行改进而得到的方法。LNLMSN是在NLMSN的基础上,引入Laguerre时延单元,使得这两种方法在取得相同信噪比改善量的同时,减少了滤波器阶数,降低了方法实现的复杂度。仿真结果表明,与原方法相比,改进方法的抗干扰性能有了较大提高。 相似文献