共查询到20条相似文献,搜索用时 15 毫秒
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针对填补零的OFDM(ZP-OFDM)系统,提出了一种新的基于子空间的自适应半盲信道估计算法。该算法利用ZP-OFDM系统导频信息,给出精确的信道参数初始值。然后通过一种新的子空间跟踪以及功率方法,进行自适应信道估计。该算法不仅降低了计算复杂度,而且改善了盲信道估计收敛速度慢的缺点,仿真结果也表明其具有较好的估计精度。 相似文献
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Ulf Jnsson 《国际强度与非线性控制杂志
》1998,8(3):279-293
》1998,8(3):279-293
Stability of systems with hysteresis nonlinearities, parametric uncertainty and finite dimensional unmodelled dynamics is considered. Conditions for exponential decay of the signals in the system to an equilibrium position are given. The equilibrium is generally not unique. The stability condition is given in terms of a frequency domain inequality, which involves the transfer function of the nominal system and a multiplier, The search for a suitable multiplier can be performed by use of convex optimization in terms of linear matrix inequalities. A simple example is given that illustrates our result. © 1998 John Wiley & Sons, Ltd. 相似文献
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Parameter identification of Wiener systems with multisegment piecewise-linear nonlinearities 总被引:2,自引:0,他引:2
Jozef Vrs 《Systems & Control Letters》2007,56(2):99-105
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Kemei Zhang 《International journal of control》2013,86(8):1576-1585
This paper considers the finite-time stabilisation for a class of high-order nonlinear systems with both low-order and high-order nonlinearities. Based on the finite-time Lyapunov stability theorem together with the methods of dynamic gain control and adding one power integrator, a state feedback controller with gains being tuned online by two dynamic equations is proposed to guarantee the global finite-time stabilisation of the closed-loop system. 相似文献
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提出了一种在最大幅值方向上进行峰值处理的子载波预留方法,同时还利用改进的牛顿迭代算法,进一步降低了子载波预留方法的计算开销。与B.S.Krongold和D.L.Jones提出的积极集子载波预留方法相比,该方法在有效处理复基带信号峰值的同时,明显降低了系统计算复杂度。仿真和分析表明,这种基于最大幅值方向的子载波预留方法是一种更为简单、有效的峰值处理方法。 相似文献
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ZHANG Jian-kang MU Xiao-min CHEN En-qing YANG Shou-yi 《通讯和计算机》2008,5(12):49-54
This paper deals with the estimation of the channel impulse response (CIR) in orthogonal frequency division multiplexing (OFDM) systems. In particular, we focus on the maximum likelihood (ML) estimator. The ML estimator is simpler to implement as it needs no information on the channel statistics, but its performance depends on the assumed effective order of channel impulse response (EOCIR). In this paper, we propose a novel ML channel estimator which combines the ML estimation with a strategy of linear search. The proposed method introduces a few complexities, but, compared with the existing ML channel estimators, it is highly robust to variation of EOCIR Its performance has been proved using theoretical analysis and simulations. 相似文献
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An equivalent multi-input multi-output (MIMO) linear model of the standard transceiver for OFDM/OQAM systems is derived. Specifically, the impulse response of the equivalent filter that determines the effect on each output of the symbol sequence transmitted on each subcarrier, both with reference to AWGN and multipath channels, is obtained. The derived model is exploited for the design of the optimum single-tap per-subcarrier equalizer according to the maximum signal-to-interference ratio criterion. It is shown that the optimum single-tap equalizer in the absence of guard subcarriers is the inverse of a specific coefficient of an impulse response of the derived MIMO model. This coefficient under particular conditions leads to the conventionally used single-tap equalizer given by the inverse of the channel frequency response at the frequency of the considered subcarrier. The effects of guard subcarriers and the inclusion of the noise term in the cost function are also studied. 相似文献
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This paper is concerned with the state estimation problem for the complex networked systems with randomly occurring nonlinearities and randomly missing measurements. The nonlinearities are included to describe the phenomena of nonlinear disturbances which exist in the network and may occur in a probabilistic way. Considering the fact that probabilistic data missing may occur in the process of information transmission, we introduce the randomly data missing into the sensor measurements. The aim of this paper is to design a state estimator to estimate the true states of the considered complex network through the available output measurements. By using a Lyapunov functional and some stochastic analysis techniques, sufficient criteria are obtained in the form of linear matrix inequalities under which the estimation error dynamics is globally asymptotically stable in the mean square. Furthermore, the state estimator gain is also obtained. Finally, a numerical example is employed to illustrate the effectiveness of the proposed state estimation conditions. 相似文献
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在正交频分复用系统中,信道的时变特点导致严重的子载波间干扰,同时,由振荡器产生的相位噪声会带来公共相位错误和子载波间干扰,这都使OFDM系统的性能急剧恶化。基于分数倍基扩展模型,利用重叠导频和最小均方准则,对时变信道和相位噪声联合估计。仿真结果表明,所提出的算法可以提高信道估计质量。 相似文献
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Yongchao Man 《International journal of control》2020,93(3):689-699
ABSTRACTThis paper is devoted to the global output-feedback stabilisation for a class of nonlinear systems with inherent nonlinearities and coarse disturbance. Remarkably, the disturbance may be non-periodic, non-differentiable and/or of unknown magnitude, and hence some critical requirements on the disturbance in the existing related literature are successfully removed. Recognising that the strategies of disturbance compensation, such as internal model principle, sliding mode control method, learning method and active disturbance rejection control method, are quite hard or even impossible to apply, a time-varying design scheme is developed in the paper. Moreover, the serious unknowns and time-variations reflected in the growth rate of the system are also dealt with by the proposed scheme. By designing a time-varying output-feedback controller, all the signals of the resulting closed-loop system are globally bounded, and the original system state and the observer state ultimately converge to zero. 相似文献
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An adaptive low-gain integral control framework is developed for tracking constant reference signals in a context of finite-dimensional, exponentially stable, single-input, single-output linear systems with positive steady-state gain and subject to locally Lipschitz, monotone input and output nonlinearities of a general nature: the input nonlinearity is required to satisfy an asymptotic growth condition (of sufficient generality to accommodate nonlinearities ranging from saturation to exponential growth) and the output nonlinearity is required to satisfy a sector constraint in those cases wherein the input nonlinearity is unbounded. 相似文献
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OFDM联合时延和到达角度的定位算法 总被引:1,自引:1,他引:0
本文提出一种基于OFDM信号的联合TOA/AOA的二维定位方法.根据信道的频率响应(CFR),算法采用超分辨率估计算法,估计首达路径(First Arrival Path,FAP)的传输时延,即TOA估计.利用天线阵列,在频域利用同样的超分辨率估计算法,估计信号各径的AOA.联合首达路径的TOA和AOA信息,可在二维平面上确定目标位置.对于AOA的估计,采用波束成形,结合各径信道脉冲响应(CIR)幅值,甄别出首径的AOA.在多径环境下仿真,结果表明算法有效且定位精度满足实际需要,特别适合只有一个基站或接入点的室内定位. 相似文献
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OFDM是未来4G中的关键技术之一.分析OFDM技术的基本原理以及OFDM调制/解调的实现及其循环前缀的基本原理,最后将OFDM与CDMA的技术特点进行比较分析. 相似文献
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In this paper, we study the global output feedback stabilisation of a class of high-order nonlinear systems with more general low-order and high-order nonlinearities. By constructing the novel Lyapunov function and observer, based on the homogeneous domination theory together with adding a power integrator method, an output feedback controller is developed to guarantee the equilibrium of the closed-loop system globally uniformly asymptotically stable. 相似文献