In this correspondence, we consider a partially decoupled variation of the rls algorithm. It is based on a constrained optimization of the cumulative filter error using the higher order sets of filter weights to impro...
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In this correspondence, we consider a partially decoupled variation of the rls algorithm. It is based on a constrained optimization of the cumulative filter error using the higher order sets of filter weights to improve on the performance of the lower order weight sets whose values are already established. From this constrained optimization, a recursive algorithm is developed whose form closely resembles the standard Volterra rls algorithm hut with structural differences that arise from eliminating the dependence of the lower order weight sets on the higher order weight sets while retaining the dependence of the higher order weights on the lower order weights. The resulting algorithm, while suboptimal, requires less computational effort than the fully coupled version, converges to steady state in the same amount of time, and is shown by example not to exhibit a substantial degradation in performance.
Nonlinear adaptive filtering techniques for system identification (based on the Volterra model) are widely used for the identification of nonlinearities in many applications. In this correspondence, the improved track...
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Nonlinear adaptive filtering techniques for system identification (based on the Volterra model) are widely used for the identification of nonlinearities in many applications. In this correspondence, the improved tracking capability of a numeric variable forgetting factor recursive least squares (NVFF-rls) algorithm is presented for first-order and second-order time-varying Volterra systems under a nonstationary environment. The nonlinear system tracking problem is converted into a state estimation problem of the time-variant system. The time-varying Volterra kernels are governed by the first-order Gauss-Markov stochastic difference equation, upon which the state-space representation of this system is built. In comparison to the conventional fixed forgetting factor recursive least squares algorithm, the NVFF-rls algorithm provides better channel estimation as well as channel tracking performance in terms of the minimum mean square error (MMSE) for first-order and second-order Volterra systems. The NVFF-rls algorithm is adapted to the time-varying signals by using the updating prediction error criterion, which accounts for the nonstationarity of the signal. The demonstrated simulation results manifest that the proposed method has good adaptability in the time-varying environment, and it also reduces the computational complexity.
The convergence characteristics of the adaptive beamformer with the rls algorithm are analyzed in this paper. In case of the rls adaptive beamformer, the convergence characteristics are significantly affected by the s...
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The convergence characteristics of the adaptive beamformer with the rls algorithm are analyzed in this paper. In case of the rls adaptive beamformer, the convergence characteristics are significantly affected by the spatial characteristics of the signals/noises in the environment. The purpose of this paper is to show how these physical parameters affect the convergence characteristics. In this paper, a typical environment where a few directional noises are accompanied by background noise is assumed, and the influence of each component of the environment is analyzed separately using rank analysis of the correlation matrix. For directional components, the convergence speed is faster for a smaller number of noise sources since the effective rank of the input correlation matrix is reduced. In the presence of background noise, the convergence speed is slowed down due to the increase of the effective rank. However, the convergence speed can be improved by controlling the initial matrix of the rls algorithm. The latter section of this paper focuses on the physical interpretation of this initial matrix, in an attempt to elucidate the mechanism of the convergence characteristics.
Nonlinearity of amplifiers and/or loudspeakers gives rise to nonlinear echo in acoustic systems, which seriously degrades the performance of speech and audio communications. Many nonlinear acoustic echo cancellation (...
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Nonlinearity of amplifiers and/or loudspeakers gives rise to nonlinear echo in acoustic systems, which seriously degrades the performance of speech and audio communications. Many nonlinear acoustic echo cancellation (AEC) methods have been proposed. In this paper, a simple yet efficient nonlinear echo cancellation scheme is presented by using an adaptable sigmoid function in conjunction with a conventional transversal adaptive filter. The new scheme uses the least mean square (LMS) algorithm to update the parameters of sigmoid function and the recursive least square (rls) algorithm to determine the coefficient vector of the transversal filter. The proposed AEC is proved to be convergent under some mild assumptions. Computer simulations show that the proposed scheme gives a superior echo cancellation performance over the well known Volterra filter approach when the echo path suffers from the saturation-type nonlinear distortion. More importantly, the new AEC has a much lower computational complexity than the Volterra-filter-based method.
Underwater acoustic channels have the features of sparse and time varying. Adaptive filter has become a common and useful tool for underwater acoustic communications over the sparse and time-varying channels. In this ...
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ISBN:
(纸本)9781467399784
Underwater acoustic channels have the features of sparse and time varying. Adaptive filter has become a common and useful tool for underwater acoustic communications over the sparse and time-varying channels. In this paper, we propose a novel homotopy dichotomous coordinate descent (DCD) recursive least squares (rls) adaptive filtering algorithm, which incorporates the variable forgetting factor (VFF). Compared with the conventional rls-type algorithms, the proposed algorithm can obtain its performance via two aspects: 1) making a remarkable improvement in a sparse fast time varying underwater acoustic channel and 2) reducing the computational complexity by using Homotopy DCD iterations. Numerical and lake experimental results show that the proposed algorithm has better tracking ability and a lower steady-state normalized mean square error (NMSE).
Adaptive algorithms are widely used for support a wide range of applications. The attractive one application is an echo canceller in the long distance telephone network. The performance improvement of the echo cancell...
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ISBN:
(纸本)9788993215069
Adaptive algorithms are widely used for support a wide range of applications. The attractive one application is an echo canceller in the long distance telephone network. The performance improvement of the echo cancellers depends on the choice of the adaptive filtering algorithm. Therefore, in this paper the variable forgetting factor recursive least squares (rls) algorithm for adaptive lattice structure filter for the echo canceller in telephone network is presented. The proposed echo canceller provides high performance and low misadjustment in steady state for all considered noise distributions.
The problems of power supply voltage quality, system losses and power demand are increasing serious, load voltage characteristics need to be studied to solve these problems. The time-varying ZIP model can represent vo...
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ISBN:
(纸本)9781728153018
The problems of power supply voltage quality, system losses and power demand are increasing serious, load voltage characteristics need to be studied to solve these problems. The time-varying ZIP model can represent voltage dependence of loads and capture the load characteristics. This paper proposes the improved recursive least square (rls) algorithm which based on cumulant and variable forgetting factor to estimate time-varying ZIP model parameters, the proposed method can suppress the influence of noise and track the change of parameters quickly, and the results of simulation show the method has good tracking performance and strong robustness.
In this paper, the adaptive Recursive Least-Squares algorithm is derived for the Lattice-Hammerstein filter leading to the proposed rls Lattice-Hammerstein nonlinear adaptive filter. The performance of the proposed al...
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ISBN:
(纸本)0780391799
In this paper, the adaptive Recursive Least-Squares algorithm is derived for the Lattice-Hammerstein filter leading to the proposed rls Lattice-Hammerstein nonlinear adaptive filter. The performance of the proposed algorithm is compared to both SG Lattice-Hammerstein and LMS Transversal-Hammerstein algorithms in a nonlinear channel modeling scenario. It is shown that the convergence rate of the rls Lattice-Hammerstein algorithm is much higher than the other two with a lower steady-state error. Simplicity of the Hammerstein structure compared to the Volterra expression makes is more appropriate for modeling and equalizing nonlinear channels.
The recently proposed recursive least-squares (rls) algorithm for trilinear forms, namely rls-TF, was designed for the identification of third-order tensors of rank one. In this context, a high-dimension system identi...
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ISBN:
(纸本)9781728189215
The recently proposed recursive least-squares (rls) algorithm for trilinear forms, namely rls-TF, was designed for the identification of third-order tensors of rank one. In this context, a high-dimension system identification problem can be efficiently addressed (gaining in terms of both performance and complexity) based on tensor decompositions and modelling. In this paper, following the framework of the rls-TF, we propose a regularized version of this algorithm, where the regularization terms are incorporated within the cost functions. Furthermore, the optimal regularization parameters are derived, aiming at attenuating the effects of the system noise. Simulation results support the performance features of the proposed algorithm, especially in terms of its robustness in noisy environments.
A non-invasive activity monitoring using Mach-Zehnder interferometer (MZI) is presented and recursive least square (rls) algorithm is performed to classify presence and absence activity states with accuracy higher tha...
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ISBN:
(纸本)9781728127644
A non-invasive activity monitoring using Mach-Zehnder interferometer (MZI) is presented and recursive least square (rls) algorithm is performed to classify presence and absence activity states with accuracy higher than 98.5% within 1 second.
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