Data selection can be used in conjunction with adaptive filtering algorithms to avoid unnecessary weight updating and thereby reduce computational overhead. This paper presents a novel correntropy-based data selection...
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作者:
Paulo S.R.DinizCOPPE/Poli
Federal University of Rio de Janeiro Program of Electrical Engineering and Department of Electrical and Computer Engineering
The current trend of acquiring data pervasively calls for some data-selection strategy, particularly in the case a subset of the data does not bring enough innovation. As a byproduct, in addition to reducing power con...
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The current trend of acquiring data pervasively calls for some data-selection strategy, particularly in the case a subset of the data does not bring enough innovation. As a byproduct, in addition to reducing power consumption and some computation, the discarding of data results in more accurate parameter estimation. In many practical situations, it is possible to verify if the acquired set of data qualifies to improve the related statistical inference or if it consists of an outlier or a noninnovative entry. In this presentation, we discuss some adaptive filtering and machine learning algorithms enabling data selection which also address the censorship of outliers measured through unexpected high estimation errors. The resulting algorithms allow the prescription of how often the acquired data is expected to be incorporated in the learning process based on some a priori assumptions regarding the environment data or some simple estimation based on the available data. Test results show the effectiveness of the proposed algorithms for selecting the innovative data without sacrificing the estimation accuracy, while reducing the computational cost. In neural networks applications the strategy leads to reduced training errors and improved test results.
This article presents a low-complexity parametric algorithm for the estimation of the carrier frequency offset (CFO) in orthogonal frequency division multiplexing systems. The proposed algorithm is equivalent to the U...
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This article presents a low-complexity parametric algorithm for the estimation of the carrier frequency offset (CFO) in orthogonal frequency division multiplexing systems. The proposed algorithm is equivalent to the Unitary ESPRIT algorithm, originally devised for estimating the direction-of-arrival of a wave front, now applied to the CFO scenario. It is verified that the proposed algorithm reduces the overall computational complexity in around 40%, while sustaining the error-rate performance achieved by the standard ESPRIT algorithm.
In orthogonal frequency division multiplexing (OFDM), carrier frequency offset (CFO) must be mitigated since it generates interference between received symbols transmitted through different sub-carriers. This paper pr...
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In orthogonal frequency division multiplexing (OFDM), carrier frequency offset (CFO) must be mitigated since it generates interference between received symbols transmitted through different sub-carriers. This paper presents a new algorithm for CFO estimation with reduced computational complexity. The new approach is based on the segmentation of the input-signal autocorrelation matrix into the noise and signal subspaces, the latter being employed to estimate the desired CFO. Simulations validate the effectiveness of the new algorithm in comparison to the traditional parametric estimation technique ESPRIT.
The aim of this work is to present an alternative method for estimating the direction-of-arrival (DoA), that is, the incoming angle, of a signal impinging on an antenna array. The proposed method is similar to ESPRIT ...
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The aim of this work is to present an alternative method for estimating the direction-of-arrival (DoA), that is, the incoming angle, of a signal impinging on an antenna array. The proposed method is similar to ESPRIT ...
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The aim of this work is to present an alternative method for estimating the direction-of-arrival (DoA), that is, the incoming angle, of a signal impinging on an antenna array. The proposed method is similar to ESPRIT (estimation of signal parameters via rotational invariance techniques) algorithm, which is the most widely used technique for this application. The new algorithm exploits the structural similarities between ESPRIT and the Tong-Xu-Kailath method for blind channel equalization. The result is an ESPRIT-like algorithm for DoA estimation with substantially reduced computational complexity. Simulation results are included to verify the properties and performance of the new covariance-based DoA algorithm, in comparison to ESPRIT and to the theoretical Cramer-Rao lower bound.
A novel methodology for first allocating the poles and zeros of a group delay equalizer is introduced. In this paper, feed-forward neural networks are used, instead of empirical formulae. The results obtained with the...
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A novel methodology for first allocating the poles and zeros of a group delay equalizer is introduced. In this paper, feed-forward neural networks are used, instead of empirical formulae. The results obtained with the networks can be applied as the initial solution of an optimization procedure that searches for the optimum group delay equalizer. Different inputs are considered a priori for the neural networks, but after pre-processing the acquired data, some of them are discarded. By evaluating cross-correlation between the inputs and the outputs, the simplified networks are designed through an optimization procedure with mean square error back-propagation, by batch method. Armijo search method is applied in this procedure for improving convergence rate. Simulation results proving the efficiency of the proposed method are presented. Quasi-equiripple group delay responses are obtained with the neural network initial estimate, avoiding local minima and improving the convergence rate of the optimization step of the equalizer designs.
In this article we derive conditions for existence of zero-forcing multiuser detectors which achieve perfect reconstruction of the transmitted symbols. Compared to similar works in the literature, the derived conditio...
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In this article we derive conditions for existence of zero-forcing multiuser detectors which achieve perfect reconstruction of the transmitted symbols. Compared to similar works in the literature, the derived conditions allow a reduction in the length of the equalizer filters, while imposing no constraints on the channel order and on the order of the precoder filters. Since the analysis is carried out in time domain, time-varying filters are also considered.
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