Variable step-size LMS adaptive filters for CDMA multiuser detection

Due to its simplicity the adaptive Least Mean Square (LMS) algorithm is widely used in Code-Division Multiple access (CDMA) detectors. However its convergence speed is highly dependent on the eigen value spread of the input covariance matrix. For highly correlated inputs the LMS algorithm has a slow convergence which require long training sequences and therefore low transmission speeds. Another drawback of the LMS is the trade-off between convergence speed and steady-state error since both are controlled by the same parameter, the step-size. In order to eliminate these drawbacks, the class of Variable Step-Size LMS (VSSLMS) algorithms was introduced. In this paper, we study the behavior of some algorithms belonging to the class of VSSLMS for training based multiuser detection in a CDMA system. We show that the proposed Complementary Pair Variable Step-Size LMS algorithms highly increase the speed of convergence while reducing the trade-off between the convergence speed and the output error.

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A Variable Step-Size for Sparse Nonlinear Adaptive Filters

2020 28th European Signal Processing Conference (EUSIPCO) ◽

10.23919/eusipco47968.2020.9287864 ◽

2021 ◽

Author(s):

Alberto Carini ◽

Markus V. S. Lima ◽

Hamed Yazdanpanah ◽

Simone Orcioni ◽

Stefania Cecchi

Keyword(s):

Adaptive Filters ◽

Variable Step Size ◽

Step Size ◽

Variable Step

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Delayless Block Individual-Weighting-Factors Sign Subband Adaptive Filters With an Improved Band-Dependent Variable Step-Size

IEEE Access ◽

10.1109/access.2020.3029269 ◽

2020 ◽

Vol 8 ◽

pp. 185796-185803

Author(s):

Jung-Hee Kim ◽

Jeong-Hwan Choi ◽

Sang Won Nam ◽

Joon-Hyuk Chang

Keyword(s):

Adaptive Filters ◽

Variable Step Size ◽

Step Size ◽

Weighting Factors ◽

Variable Step

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Novel variable step size constant modulus algorithms for blind multiuser detection

IEEE 54th Vehicular Technology Conference. VTC Fall 2001. Proceedings (Cat. No.01CH37211) ◽

10.1109/vtc.2001.956855 ◽

2002 ◽

Cited By ~ 4

Author(s):

Zhimin Du ◽

Sheng Zhou ◽

Peng Wan ◽

Weiling Wu

Keyword(s):

Multiuser Detection ◽

Variable Step Size ◽

Constant Modulus ◽

Step Size ◽

Blind Multiuser Detection ◽

Variable Step

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Variable Step-Size Block Least Mean Square Adaptive Filters

2006 International Conference on Industrial and Information Systems ◽

10.1109/iciis.2006.365797 ◽

2006 ◽

Cited By ~ 3

Author(s):

M. S. E. Abadi ◽

S. Z. Mousavi ◽

A. Hadei

Keyword(s):

Adaptive Filters ◽

Variable Step Size ◽

Mean Square ◽

Least Mean Square ◽

Step Size ◽

Variable Step

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Variable Step-Size Pradhan-Reddy Subband Adaptive Filters

2005 5th International Conference on Information Communications & Signal Processing ◽

10.1109/icics.2005.1689181 ◽

2006 ◽

Cited By ~ 1

Author(s):

M.S.E. Abadi ◽

J.H. Husoy

Keyword(s):

Adaptive Filters ◽

Variable Step Size ◽

Step Size ◽

Variable Step

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Variable Step Size LMS Algorithm Based on Two Cooperative Adaptive Filters

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.268-270.1168 ◽

2011 ◽

Vol 268-270 ◽

pp. 1168-1172

Author(s):

Qing Feng Wang ◽

Chuan Lin

Keyword(s):

Adaptive Filter ◽

Adaptive Filters ◽

Lms Algorithm ◽

Variable Step Size ◽

Step Size ◽

Output Noise ◽

Variable Step ◽

Tracking Ability ◽

New Algorithms ◽

Current Stage

A new variable step size LMS algorithm (CoLMS algorithm) based on two cooperative adaptive filters was proposed. In the CoLMS algorithm, the step size of each component filter was adjusted according to the comparison result of the two component filters’ performance at current stage. And the output of the better component adaptive filter was chosen as that of the overall adaptive filter. The CoLMS algorithm is not sensitive to the magnitude of the output noise and has a good tracking ability in the stationary or slowly changed environment. In order to further improve the tracking ability of CoLMS in abruptly changed environment, a modified CoLMS algorithm is also presented. The efficiency of the new algorithms is verified by the simulation results in system identification under the noises of different magnitudes.

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Variable Step Size Maximum Correntropy Criteria Based Adaptive Filtering Algorithm

Engineering, Technology & Applied Science Research ◽

10.48084/etasr.626 ◽

2016 ◽

Vol 6 (2) ◽

pp. 923-926

Author(s):

S. Radhika ◽

A. Sivabalan

Keyword(s):

Steady State ◽

Adaptive Filters ◽

Impulsive System ◽

Variable Step Size ◽

Step Size ◽

Impulsive Interference ◽

Variable Step ◽

Improved Performance ◽

Maximum Correntropy Criterion ◽

State Error

Maximum correntropy criterion (MCC) based adaptive filters are found to be robust against impulsive interference. This paper proposes a novel MCC based adaptive filter with variable step size in order to obtain improved performance in terms of both convergence rate and steady state error with robustness against impulsive interference. The optimal variable step size is obtained by minimizing the Mean Square Deviation (MSD) error from one iteration to the other. Simulation results in the context of a highly impulsive system identification scenario show that the proposed algorithm has faster convergence and lesser steady state error than the conventional MCC based adaptive filters.

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