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IEEE 74th Vehicular Technology Conference (VTC)

作者： Leite, Joao P. De Carvalho, Paulo Henrique P. Vieira, Robson D. Univ Brasilia Dept Elect Engn Campus Univ Darcy Ribeiro Brasilia DF Brazil Nokia Technol Inst INdt Brasilia DF Brazil

ISBN: (纸本)9781424483273

Multiuser MIMO (MU MIMO) communications have attracted considerable attention in the last years since these systems are able to offer the higher link capacity of MIMO systems as long as channel state information (CSI) is available at the transmitter, so that the spatial properties of the channel can be exploited by precoding. However, the time varying nature of the channel and other transmissions constraints may cause CSI to be outdated, degrading the performance of the system. Considering this scenario, channel prediction can provide up-to-date channel CSI and reduce the performance loss. This paper presents a channel predictor based on the set-membership affine projection (SM-AP) filtering as way to compensate the outdated CSI. A realistic standardized channel model is used to evaluate the influence of the proposed predictor on two classical precoding schemes of the MIMO broadcast channel of a multiuser scenario, namely zero-forcing vector perturbation. The performance of the predictor is compared to the well-known adaptive algorithms normalized least mean squares (nlms) and recursive least squares (RLS). Simulation results show that the SM-AP predictor has lower computational cost and superior performance when compared to the classical algorithms.

关键词： CSI MIMO MIMO broadcast channel MIMO communication MU MIMO communication nlms algorithm OFDM Prediction algorithms RLS algorithm SM-AP filtering Transmitting antennas Vectors Wireless communication adaptive algorithm affine transforms broadcast channels c

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Effective Adaptive Noise Canceller Design Using Normalized LMS 1

Effective Adaptive Noise Canceller Design Using Normalized L...

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1st International Conference on Next Generation Computing Technologies (NGCT)

作者： Kumari, Raj Mehra, Rajesh Shrama, Lalita NITTTR Dept Elect & Commun Engn Chandigarh India NITTTR Chandigarh India Shoolini Univ Solan India

ISBN: (纸本)9781467368094

This paper presents the application of Adaptive filters in noise cancellation during various communication processes, where non-stationary signals are transmitted. Adaptive filter estimates the noise signal and by applying the appropriate weights the estimated noise signal is eliminated from the information. For noise cancellation applications most efficient Adaptive filter algorithms LMS and its normalized form nlms are used and their comparative analysis is done in form of their output power, error power and SNR. In both of the algorithms concept of negative feedback is utilized in the cancellation of noise from the signal and thus both of these are also called negative feedback algorithms. Implementation and analysis is done by applying different step sizes on different order of filter. Order of filter is taken as 4, 8, 12 and then by changing the values of coefficients the graphical and computational analysis is done. Finally an efficient design using nlms algorithm is implemented where order is taken as 8 and step size 0.2. This results as a low error power (11.7221 db) and a high value of SNR (1.1445) than that of LMS algorithms.

关键词： Adaptive Filters Error Power LMS algorithm nlms algorithm SNR

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A Novel Automatic Step-Size Adjustment Approach in the LMS algorithm

A Novel Automatic Step-Size Adjustment Approach in the LMS A...

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1st International Conference on Wireless Communication, Vehicular Technology, Information Theory and Aerospace and Electronic Systems Technology

作者： Wang, Peijie Kam, Pooi Yuen Chia, Meng Wah Natl Univ Singapore Dept Elect & Comp Engn S-117576 Singapore Singapore

ISBN: (纸本)9781424440665

A variable step-size is necessary in the least-mean-square (LMS) algorithm to achieve both fast convergence and a small final excess mean-square estimation error. As a well-studied area, many variations of the LMS algorithm with variable step-sizes have been proposed in the literature. A common point in these algorithms is that the step-size is computed according to some pre-specified formulas with preset control parameters, and therefore the generated step-size is a predetermined constant at each single time point. In this paper, we propose a novel parameter-free step-size adjustment approach, in which the step-size is viewed as a variable, and rechosen at each new time point to minimize a least-squares cost function. Experiments for the linear prediction of random processes show the effectiveness of the proposed approach in rapidly driving the mean-square estimation error to a small final steady-state value. The most significant feature of the new approach is that no control parameters need to be set in advance.

关键词： LMS algorithm nlms algorithm variable step-size

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A Mechanism for Switching Adaptive Filter algorithms in Suddenly Time-Varying Environments 53

A Mechanism for Switching Adaptive Filter Algorithms in Sudd...

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SICE Annual Conference (SICE)

作者： Matsuzaki, Hidenori Hikawa Kohbou Saitama Japan

ISBN: (纸本)9784907764456

This paper proposes an adaptive filtering system where a least-square algorithm and a stochastic gradient algorithm are alternately switched depending on its operational mode. The switching mechanism is quite simple and realized with a small amount of computational cost. Several numerical examples show that the resulting filter could achieve both sufficiently fast convergence and enhanced robustness in suddenly time-varying system environments.

关键词： Adaptive filtering fast RLS algorithm nlms algorithm time-varying system

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An introduction to EIP-nlms post-processing method for cross-talk cancellation in BSS outputs

An introduction to EIP-NLMS post-processing method for cross...

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International Conference on Computer and Automation Engineering

作者： Tahereh Noohi Hasti Shabani Mohammad Hossein Kahaei Signal & System Modeling Lab School of Electrical Engineering Iran University of Science and Technology Tehran Signal & SystemModeling Lab School of Electrical Engineering Iran University of Science and Technology Tehran

ISBN: (纸本)9781424455690

In this paper, we propose a new post-processing method to suppress the residual cross-talk of Blind Source Separation (BSS) outputs. This method relies on the existence of the so called Exclusive Inactivity Periods (EIPs) in the source signals during which all sources are active except one. After detecting EIPs, we use the Normalized Least-Mean-Square (nlms) algorithm to estimate the cross-talk in these regions. Simulation results show the ability of the proposed method in suppressing the residual cross-talk without distorting the target signal and improving the SIR about 3 dB compared to the nlms post-processing [5].

关键词： Blind Source Separation Post-processing Exclusive Inactivity Periods (EIPs) nlms algorithm

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A NEW PERFORMANCE MEASURE OF THE NORMALIZED LMS ADAPTIVE FILTER

A NEW PERFORMANCE MEASURE OF THE NORMALIZED LMS ADAPTIVE FIL...

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IEEE International Conference on Signal Processing and Communications

作者： Eweda, Eweda Ajman Univ Dept Elect Engn Ajman U Arab Emirates

ISBN: (纸本)9781424412358

The paper provides a new performance measure of the Normalized LMS algorithm. The performance measure is based on the time evolution of the component of the weight deviation vector in the direction of the regressor. This is the only component that contributes to the excess estimation error at the output of the adaptive filter. The main advantage of the proposed measure is that it enables a rigorous establishment of the algorithm convergence under weak assumptions. The assumptions do not include restrictions on the dependence between successive regressors, the dependence among the regressor elements, the length of the adaptive filter, the distributions of the filter input and the noise. Moreover, the proposed measure enables also a convergence analysis without the usual restriction of small step size of the algorithm.

关键词： Adaptive Signal Processing Adaptive Filtering nlms algorithm

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Maximum Versoria-criterion (MVC)-based adaptive filtering method for mitigating acoustic feedback in hearing-aid devices

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APPLIED ACOUSTICS 2021年 181卷 108156-108156页

作者： Akhtar, Muhammad Tahir Albu, Felix Nishihara, Akinori Nazarbayev Univ Sch Engn & Digital Sci Dept Elect & Comp Engn Kabanbay Batyr Ave 53 Nur Sultan 010000 Kazakhstan Valahia Univ Targoviste Dept Elect Targoviste 130082 Romania Tokyo Inst Technol Meguro Ku Tokyo 1528552 Japan

In any digital hearing aid (HAid), the input microphone and the receiver loudspeaker are closely located. Furthermore, HAid cannot be tightly fitted for comfort reasons. Therefore, it is almost impossible to avoid the acoustic feedback present due to the leakage path between the receiver loudspeaker and the input microphone. This paper investigates acoustic feedback cancellation (AFC) by developing a hybrid adaptive filtering approach. It is proposed to use two simultaneously adapted adaptive filters as in the previous method. The adaptation algorithms are based on a delay-based normalized least mean square (nlms) algorithm. Furthermore, gradient information from a maximum Versoria-criterion (MVC)-based algorithm is also incorporated in the proposed approach. The effectiveness of this approach is demonstrated through extensive computer simulations. (C) 2021 The Author(s). Published by Elsevier Ltd.

关键词： Acoustic feedback cancellation Hearing aids Adaptive filtering nlms algorithm Modeling signal Maximum Versoria-criterion

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Dynamics of Identification for the Normalized Least Mean Square algorithm

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IFAC Proceedings Volumes 1985年第5期18卷 1237-1242页

作者： S. Abu el Ata-Doss J.L. Estival J. Richalet ADERSA 2 avenue du ler Mai F-91120 Palaiseau France

Convergence rate of the normalized least mean square adaptive estimation algorithm is analyzed. An approximation of the adaptation coefficient value which yields the best convergence speed is derived in function of the input correlation. Results concerning the trade-off : convergence speed versus asymptotic mean square estimation error are explored to substract practical rules for the adjustment of the adaptation coefficient for best possible estimation performance within a limited time delay. These results are particularly interesting for the diagnosis and adaptive control schemes which are essentially based on real-time identification.

关键词： Adaptive estimation nlms algorithm convergence rate speed/accuracy tradeoff impulse response representation

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Boring Bar Chatter Control using Feedback Filtered-x Normalized Least Mean Square algorithm

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IFAC-PapersOnLine 2019年第10期52卷 358-363页

作者： Mohsen Fallah Behnam Moetakef-Imani Ali Hosseini Mostafa Ebrahimi CAD/CAM Laboratory Department of Mechanical Engineering Ferdowsi University of Mashhad Mashhad Iran Machining Research Laboratory Faculty of Engineering and Applied Science Ontario Tech University Oshawa Ontario Canada

This paper deals with the adaptive control of chatter vibrations in boring operations. A novel feedback control method is suggested based upon the well-known filtered-x normalized least mean square (Fxnlms) algorithm. The proposed feedback controller is implemented on the developed active boring bar that is equipped with electrodynamic shaker and accelerometer. The adaptive digital control algorithm utilizes two finite impulse response (FIR) filters in order to efficiently drive the electromagnetic actuator and successfully minimize the mean square of the chatter vibrations. Feasibility of the proposed control algorithm is verified for boring of Aluminum alloy 6063-T6. The performance of feedback Fxnlms controller is compared with the constant-gain direct velocity feedback (DVF) controller. It is observed that both control algorithms attenuate the chatter by more than 70 dB. In addition, the actuator cost is reduced by 50 percent for the optimally tuned adaptive digital controller. As a result, the proposed adaptive controller provides a robust and efficient solution for chatter suppression.

关键词： Chatter Signal processing Model-based control Adaptive digital filters nlms algorithm

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Double-talk detection method with detecting echo path fluctuation

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ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 1996年第4期79卷 82-93页

作者： Fujii, K Ohga, J Member Fujitsu Laboratories Ltd. Kawasaki Japan 211

In the echo canceller, where the normalized least mean square (nlms) algorithm is used as the adaptive algorithm, the double-talk disturbs the coefficients of the adaptive filter and increases the probability of howling generation. To cope with this phenomenon, the echo canceller usually is provided with a detector to detect the generation of the double-talk. The echo canceller is designed to minimize the disturbance by stopping the update of the adaptive filter coefficients when the double-talk is detected. In the detection of the double-talk, it is effective to monitor the increase of the residual echo since the double-talk component masked by the echo can be detected. In this method, however, the residual echo also is increased by the fluctuation of the echo path and the fluctuation of the echo path should also be detected. This paper proposes a method to differentiate between the double-talk and the echo path fluctuation, based on the magnitude of the correlation between the input-containing echo and the echo replica. In other words, the property is utilized that the correlation between the echo replica and the echo is large for the double-talk and is small for the echo path fluctuation. A double-talk detection method also is proposed where the power ratio of the residual echo and the echo replica is used as the parameter. It is shown that the double-talk detection without deteriorating at all the echo elimination can be realized by a structure with a delay preceding the coefficient update operation.

关键词： double-talk echo path fluctuation echo canceller nlms algorithm

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