基于均圆阵的扩展循环 MUSIC 算法简

将循环平稳理论引入到均匀圆阵的波达方向估计中,提出了一种基于圆阵的扩展循环MUSIC算法。同时利用信号的循环相关阵和循环共轭相关阵的信息,有效抑制了同频带内干扰和噪声的影响,实现了感兴趣信号与干扰信号的有效分离。仿真实验结果表明,所提算法具有较高的波达方向估计精度和较好的多信号分辨能力,且突破了经典MUSIC算法关于信源数不能超过阵元数的限制。     

An extended least-hop distributed routing algorithm

A routing strategy called NELHNET has been developed for networks with multiprecedence traffic and operating under dynamic traffic and topological conditions. An adaptive distributed algorithm that uses least-hop and least-hop-plus-1 routes in a table of routing vectors, as opposed to the usual table of routing scalars, is described. Current delays are passed backward and forward with the packets to allow development of expected delays to each node via all acceptable routes. The route then selected is the acceptable route with the least expected delay. For speedier recovery, a node returning to service receives the current network status from an adjoining node as soon as the link connecting them is operational. The resultant algorithms show far greater than the marginal improvements originally expected over Arpanet simulations. NELHENET strategies also permit the network to function stably under more heavily loaded conditions than do the Arpanet strategies     

Fast root MUSIC algorithm

The capabilities of the pole decomposition multiple signal classification (root-MUSIC) algorithm have been enhanced by the development of a simpler technique that allows the algorithm to operate at a much lower computational cost than was previously possible. The authors develop the approach into a new algorithm pertinent to the uniform linear array (ULA). Simulations are presented and the results evaluated against classical root-MUSIC     

Time-reversal MUSIC imaging of extended targets.

This paper develops, within a general framework that is applicable to rather arbitrary electromagnetic and acoustic remote sensing systems, a theory of time-reversal "MUltiple Signal Classification" (MUSIC)-based imaging of extended (nonpoint-like) scatterers (targets). The general analysis applies to arbitrary remote sensing geometry and sheds light onto how the singular system of the scattering matrix relates to the geometrical and propagation characteristics of the entire transmitter-target-receiver system and how to use this effect for imaging. All the developments are derived within exact scattering theory which includes multiple scattering effects. The derived time-reversal MUSIC methods include both interior sampling, as well as exterior sampling (or enclosure) approaches. For presentation simplicity, particular attention is given to the time-harmonic case where the informational wave modes employed for target interrogation are purely spatial, but the corresponding generalization to broadband fields is also given. This paper includes computer simulations illustrating the derived theory and algorithms.     

An extended inverse QR adaptive filtering algorithm

A so-called inverse QR algorithm was recently introduced for recursive adaptive filtering under the exponentially weighted least-squares criterion. It has some attractive features, including the absence of inversions. The extension to the multi-channel case does require inversion however. We present a new derivation of the inverse QR algorithm, based on the technique of Sayed and Kailath, for reformulating the above adaptive filtering problem as a state-space estimation problem. A well-known square-root covariance algorithm for the latter problem is shown to directly give (a multi-channel version of) the inverse QR algorithm. A new extended square-root covariance algorithm is then applied to get a new inversion-free ‘extended inverse QR’ algorithm, even in the multi-channel case.     

一种改进的循环谱估计算法

在有限数据条件下,提出了一种基于数据分段处理和重叠保留的改进循环谱密度估计算法,给出了算法实现的具体步骤,并从改进前后循环谱估计方差、抑制噪声能力和可靠性、分辨率几个方面详细分析了改进算法的性能,推导了相应的表达式。得出了改进算法能够减小循环谱密度估计的方差,在低信噪比时能更有效地抑制噪声对信号循环谱的影响的结论。仿真结果证明了本文所提出算法的有效性。     

An improved MUSIC algorithm for estimation of time delays inasynchronous DS-CDMA systems

The problem of near-far resistant time-delay estimation in an asynchronous direct-sequence code-division multiple-access system is considered, and by better exploiting the structure of the problem, estimators superior to previously known techniques are obtained. For a typical numerical example, a gain in signal-to-noise ratio of approximately 3 dB is obtained     

Smart MUSIC algorithm for DOA estimation

The multiple signal classification (MUSIC) algorithm has been considered to be the most effective for direction-of-arrival estimation. However, MUSIC requires considerable computation. To reduce this computational load to the extent that the sensor array system may follow rapid changes in the radio environment. The author proposes the smart MUSIC (SMUSIC) algorithm. In SMUSIC, the only requirements are the calculation of a few basis vectors and calculation of just one vector orthogonal to basis vectors. The superior characteristics of SMUSIC's reduced processing time and high resolution are simulated numerically     

一种新的二维MUSIC算法的研究

提出了一种新的基于垂直阵列结构的二维MUSIC方法来估计信号的DOA(direction of arrive)，此方法只需三个均匀直线阵就可估计用户的二维DOA。该方法利用其中的一个直线阵来组合两个线阵分别估计的一维DOA，大大改善了DOA的估计性能。仿真结果证明了该方法的有效性。     

An extended Berlekamp-Massey algorithm for the inversion ofToeplitz matrices

The Berlekamp-Massey algorithm (BMA) which solves special Toeplitz systems of linear equations is extended to an algorithm for inverting Toeplitz matrices. The original BMA itself leads to one row of the inverse of the corresponding Toeplitz matrix. The other rows are derived using the same operations that are central to the original BMA. Two alternatives for the extended BMA are presented: the first includes the usual BMA without any changes, and the second simplifies the structure by some modifications also in the original BMA part. Both versions follow a tree-like structure. If the branches of the tree are implemented in parallel, the time demand would be nearly the same as for the usual BMA. In contrast to other Toeplitz algorithms, only slight modifications must be incorporated to handle singular submatrices     

一种改进的MUSIC方法

多级维纳滤波是一种降维算法,文中将多级维纳滤波引入到多重信号分类(MUSIC)算法中,提出了适合于MUSIC方法的多级维纳滤波器结构。该方法避免了采样数据协方差矩阵的特征值分解,降低了运算量。仿真结果证明了方法的有效性。     

基于改进多信号分类算法的波达方向估计

针对传统波达方向估计算法在低信噪比条件下性能表现不佳的问题,本文提出了一种基于改进多信号分类的波达方向估计算法。本文首先对多信号分类算法的不足进行分析,并采用时间平滑技术构建相关矩阵,然后采用相关矩阵建立空间谱函数达到波达方向估计,最后采用仿真实验对算法的性能进行测试。结果表明,本文算法可以快速准确的估计出多个信号的波达方向,降低了波达方向估计误差,而且性能远远优于其它改进多信号分类算法。     

Probability of resolution of the MUSIC algorithm

The MUSIC algorithm is well known for its high-resolution capability, and various aspects of its statistical performance have been investigated. However, rigorous asymptotic analysis of one of its most important performance measures, the probability of resolution, is not available yet. We analyze the probability of the MUSIC algorithm resolving two spatially separated signal sources in the context of array processing. By formulating the resolution problem in the framework of statistical decision theory and directly determining the probability density function (PDF) of the indefinite and singular quadratic form that defines the resolution event, we arrive at an exact asymptotic formula for the probability of resolution. This is accomplished by a multistep procedure. Computer simulations have been performed to confirm the validity of the theory     

MUSIC算法的DoA估计时间分析

在基于波束赋形(Beamforming)的无线通信系统中,使用MUSIC算法的波达方向(Direction of Arrival,DOA)估计具有良好的性能。但是,对于MUSIC算法在低信噪比下Do A估计时间和精度之间的关系,却一直未有深入研究。因此,对均匀圆阵数学模型和MUSIC算法进行分析,研究样本数量与DOA估计精度的关系。仿真结果表明,在低信噪比下,DOA估计性能下降,通过增加估计协方差矩阵的样本数量,可以提高MUSIC算法的性能。根据仿真结果,拟合发现DOA估计角度分辨率达到1度,所需样本数量和信噪比的关系服从负指数分布。     

一种扩展的Rijndael算法及其DSP快速实现的研究

研究一种扩展的Rijndael算法的设计策略，重点研究了列混合变换及其逆变换的设计；在此基础上，研究列混合变换中字节模乘运算的实现算法，根据这种扩展算法加密轮的4个变换的特征，提出了两种快速实现方案。在DSP平台上实现该扩展算法的基础上，对该扩展算法的ANSI C代码进行综合优化，并取得良好的效果。另外，本文从雪崩效应角度分析了算法的安全性.     

An extended TOPS algorithm based on incoherent signal subspace method

In this paper, we present an improved algorithm for wideband direction finding of far-field sources impinging on an array with a known arbitrary geometry. This algorithm is based on the test of orthogonality of projected subspaces (TOPS), so that it can be considered as an extension of TOPS algorithm (ETOPS). Due to using more information from several reference frequencies, the performance of the proposed method outperforms that of TOPS with arbitrarily chosen reference frequency, and varies with the number of the reference frequencies used. Although ETOPS needs more computation loads, each TOPS spectrum can be calculated individually. So, it is possible to obtain them at the same time in practice, which makes the proposed algorithm parallelizable easily and further speeds up the processing in practical implementation. Simulation results validate the effectiveness of our method.     

一种解耦合二维MUSIC算法研究

针对目前多信号环境中信号的测频测向问题,利用非均匀时延,解开频率和信号到达角之间存在的耦合,在此基础上实现了解耦合的二维MUSIC算法。可同时测量信号频率和到达角,计算量小,并保持了MUSIC算法测量精度高的特点。仿真结果证明了该方法的有效性。     

一种三维调制信号的MUSIC解调方法

根据三维调制信号的特性,提出了一种三维调制信号的多重信号分类(MUSIC)解调方法,通过搜索接收信号的空间谱,来估计其极化辅助角与极化相位差等信息,从而恢复出基带信号。理论分析与仿真实验结果均表明,所提出的方法能够对三维极化幅度正交调制(PQAM)信号进行有效的接收,不仅具有很高的分辨率和精确度,而且在低信噪比条件下,可以获得更低的误码率和估计误差。     

A system for systolic modules for the MUSIC algorithm

The authors believe that special-purpose architectures for digital signal processing (DSP) real-time applications will use closely coupled processing elements as array processor modules to implement the various portions of the new algorithms, and several such modules will cooperate in a pipelined manner to implement complete algorithms. Such an architecture, based upon systolic modules, for the MUSIC algorithm is presented. The architecture is suitable for VLSI implementation. The throughput of the pipelined approach is O(N), whereas the sequential approach is O(N³)     

对四阶累积量MUSIC算法的分析与应用

分析了四阶累积量MUSIC算法的构造及Toeplitz化预处理方法,讨论了谐波个数与谐波分量的振幅对算法分辨性能的影响,应用四阶累积量MUSIC算法对某运动目标的实测回波进行计算,得到了目标回波真实的谐波构造特征.