共查询到18条相似文献,搜索用时 125 毫秒
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提出了一种基于可变阈值的降秩子空间选择算法的盲降秩多用户检测技术。采用可变阈值的降秩子空间选择算法,能较快得到合适的降秩子空间,且计算结果具有可重用性。仿真结果表明,该算法能用较低的计算复杂度达到系统要求的检测性能。 相似文献
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非协作通信中的盲信噪比估计算法 总被引:3,自引:0,他引:3
为解决调制识别前端的信噪比估计问题,首先给出了一种新的基于子空间分解的盲信噪比估计算法,新算法通过利用信号的过采样率信息构造特定维数的自相关矩阵,避免了原算法中对信号和噪声空间维数的估计.同时为了降低算法计算复杂度,以及更好地跟踪信噪比的变化,给出了另一种基于PASTd的子空间跟踪算法来进行信噪比的跟踪估计.仿真结果表明,与经典的子空间分解算法相比,改进算法在性能上有着显著的优势;同时基于PASTd的信噪比估计算法相比基于子空间分解的估计算法更好地跟踪了信噪比的时变. 相似文献
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在处理大型阵列时,阵元数较多,通常对阵列采用降秩处理可以较好地解决运算量过大的问题。基于广义旁瓣相消器(GSC)框架的降秩变换自适应滤波是各种降秩自适应滤波算法的统一模型。分析了基于GSC框架的几种降秩自适应滤波算法,针对当降秩阶数大于干扰数时方向图旁瓣过高、波形混乱和系统性能下降问题,提出了一种基于GSC框架的改进降秩算法,该算法利用特征子空间对GSC阻塞矩阵加以改进,使用改进后的阻塞矩阵进行降秩自适应处理,仿真结果证明了改进算法可以降低旁瓣电平,并形成较好的波束形状,提高了GSC性能的稳健性。 相似文献
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针对基于子空间分解信噪比估计算法中信号子空间维数估计复杂度高、小样本条件下估计偏差大的问题,提出了一种改进的盲信噪比估计算法.该算法首先构造接收信号的自相关矩阵,然后从矩阵奇异值序列的尾部开始,间隔两项依次进行差分得到梯度序列,再以梯度序列相邻两项均值大干特定阈值为条件确定信号子空间的维数,最后求得信噪比.仿真结果表明:信噪比范围为-5~+15 dB时,平坦衰落信道下常用调制信号的信噪比估计标准差小于0.1 dB,与MDL,AIC方法相比,该算法计算量小,且能适应更低的信噪比和更短的数据长度. 相似文献
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本文研究了DS-SS信号的扩频序列盲估计问题,针对现有特征值分解算法失步时间估计不准和计算量大等缺点,提出一种基于改进传播算子的扩频序列盲估计算法,该算法对传统传播算子估计信号子空间的方法进行了改进,使之能够估计扩频序列,并利用信号子空间估计信号失步时间.与基于特征值分解的方法相比,本文算法提高了失步时间的估计精度,并有效的降低了计算量.最后对算法计算量和性能进行了仿真分析和验证,结果表明本文算法有效,计算量远小于现有特征值分解算法,且估计性能在低信噪比条件下更优. 相似文献
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指数阻尼正弦模型阶选择算法 总被引:1,自引:0,他引:1
本文针对指数阻尼正弦信号模型提出了一种新的基于子空间和结构总体最小范数的阶选择算法.该方法利用信号子空间移不变性以及阶与信号分量数匹配时总体误差最小原理建立模型阶估计准则.实验表明该方法获得了更高的阶估计精度.算法无需设置阈值和惩罚项,自动完成阶估计过程.它可以应用到高分辨率的谐波恢复算法中. 相似文献
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This paper assesses the frequency detection capabilities of a new signal-dependent reduced-rank linear predictor applied to autoregressive spectrum estimation. The new technique is called reduced-order correlation kernel estimation technique (ROCKET). Its detection performance is examined by comparison to a full-rank autoregressive (FR-AR) estimator and two reduced-rank principal component autoregressive (PC-AR) estimators based on both the standard signal-independent version and a modified signal-dependent method. The performance of the new autoregressive estimator is also compared as a function of rank to the popular pseudo-spectrum estimator MUSIC. The performance metrics examined are the probability of detection (P/sub D/) and the false alarm rate (FAR) of detecting the spatial frequencies of plane waves impinging on a uniform line array in additive white Gaussian noise. These metrics are studied as a function of subspace rank, sample support, and signal-to-noise ratio (SNR). Simulations show that the signal-dependent reduced-rank estimators significantly outperform both the signal-independent version of PC-AR and the FR-AR estimator for low sample support and low SNR environments. One notable characteristic of ROCKET that highlights its distinct subspace selection is its performance as a function of subspace rank. It is observed that for equal powered signals, its peak performance is nearly invariant to signal rank and that at almost any subspace rank ROCKET meets or exceeds FR-AR performance. This provides an extra degree of robustness when the signal rank is unknown. 相似文献
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基于降维噪声子空间的二维阵列DOA估计算法 总被引:1,自引:0,他引:1
为提高波达方向(Direction Of Arrival, DOA)的估计速度,该文基于子空间的正交性原理,利用噪声子空间及其共轭的交集进行奇异值分解(SVD)实现噪声子空间的降维,并基于降维噪声子空间与导向矢量及其共轭的双正交性提出一种2维阵列快速DOA估计算法。理论分析和仿真实验表明:该算法不受实际阵型的限制,能将传统MUSIC谱的角度范围压缩至原来的一半,从而将DOA估计的计算量降至传统方法的50%,并具有与MUSIC算法相当的角度分辨率。 相似文献
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A class of adaptive reduced-rank interference suppression algorithms is presented based on the multistage Wiener filter (MSWF). The performance is examined in the context of direct-sequence (DS) code division multiple access (CDMA). Unlike the principal components method for reduced-rank filtering, the algorithms presented can achieve near full-rank performance with a filter rank much less than the dimension of the signal subspace. We present batch and recursive algorithms for estimating the filter parameters, which do not require an eigen-decomposition. The algorithm performance in a heavily loaded DS-CDMA system is characterized via computer simulation. The results show that the reduced-rank algorithms require significantly fewer training samples than other reduced- and full-rank algorithms 相似文献
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Blind adaptive multiuser detection for direct sequence code division multiple access (DS-CDMA) signals over static and time-varying intersymbol interference (ISI) limited channels is considered. Blind adaptive detectors must be robustified for ISI channels, when there is significant mismatch between the received signature vector and the transmitted code (assumed known at the receiver). A new low-complexity detector is presented that improves on some previously proposed methods without explicit estimation of the ISI channel. The key innovation is a reduced-rank detector architecture combined with an efficient subspace tracker that yields direct accurate estimation of the desired user's received signature. Several representative simulation examples of detector output signal-to-noise-and-interference ratio (SINR) for fading channels are provided in support of our claims of improved efficacy of the method 相似文献
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多重信号分类(multiple signal classification: MUSIC)方法通过计算搜索导向矢量与噪声或信号子空间的距离来估计波达方向,对采样协方差矩阵的依赖性较大。在小快拍或存在强弱临近信号条件下,采样协方差矩阵的估计值与真实值通常存在较大差异,导致估计的噪声或信号子空间发生畸变,严重恶化了MUSIC方法的波达角估计性能。针对该问题,本文提出采用加权伪噪声子空间投影的改进方法(称为wpnMUSIC)。该方法在修正数据相关矩阵的基础上估计与搜索导向矢量对应的伪噪声子空间并利用其在伪噪声子空间的投影值对MUSIC空间谱进行加权处理,在保持子空间处理方法高分辨能力的同时改善了对小快拍和强弱信号的稳健性。理论分析和仿真实验表明本文方法对强弱临近目标的分辨能力优于MUSIC方法。 相似文献
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一种新的正弦波频率估计方法研究 总被引:5,自引:0,他引:5
对相关阵的最大特征值所对应的特征矢量按一定规则排列的非对称矩阵,其奇异值/奇异矢量分解(SVD)的右奇异矢量同样存在两个子空间,并因此提出了一种新的谱估计方法,即基于相关阵信号子空间的正交矢量法(Orthogonal Vector spectral estimation based on correlation matrix SignalSubspace),简称OVSS法,OVSS法源于相关阵信号子空间,对噪声和数据长度敏感性较小,同时它又是正交矢量法,且源于高阶模型,具有高阶MUSIC法的分辨率,而且是低阶矩阵SVD,没有伪峰。大量模拟试验显示OVSS法是一种具有高分辨率、高统计稳定性、计算量相对增加较小的高质量谱估计方法。 相似文献
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相干分布式目标一维波达方向估计方法 总被引:1,自引:1,他引:0
在相干分布式目标波达方向估计研究中,角信号分布函数一般具有共轭对称性.在角分布函数的数学形式未知,或角分布函数形式不同的信号源同时存在的情况下,本文提出了搜索极小最小特征值(噪声子空间)或极大最大特征值(信号子空间)的分布式目标一维波达方向估计方法,并分析了分布式目标波达方向估计的模糊性问题. 相似文献