Master's Dissertation
DOI
https://doi.org/10.11606/D.3.2009.tde-29062009-113546
Document
Author
Full name
Renato Candido
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2009
Supervisor
Committee
Silva, Magno Teófilo Madeira da (President)
Bermudez, José Carlos Moreira
Burt, Phillip Mark Seymour
Title in Portuguese
Keywords in Portuguese
Algoritmos (combinação)
Análise de algoritmos
Abstract in Portuguese
Title in English
Keywords in English
Algorithms (combination)
Analysis of algorithms
Abstract in English
In order to improve the performance of adaptive filters, the combination of algorithms is receiving much attention in the literature. This method combines linearly the outputs of two filters operating in parallel with different step-sizes to obtain an adaptive filter with fast convergence and reduced excess mean squared error (EMSE). In this context, it was proposed an affine combination of two least-mean square (LMS) filters, whose mixing parameter is not restricted to the interval [0, 1]. Hence, the affine combination is a generalization of the convex combination. In this work, the affine combination of two LMS algorithms is extended to the supervised algorithms NLMS (normalized LMS) and RLS (recursive least squares), and also to blind equalization, using the constant modulus algorithm (CMA). A steady-state analysis of the affine combination of the considered algorithms is presented in a unified manner, assuming white or colored inputs, and stationary or nonstationary environments. Through the analysis, it was observed that the affine combination of two algorithms of the same family can provide a 3 dB EMSE gain in relation to its best component filter and consequently in relation to the convex combination. To ensure that the combined estimate is at least as good as the best of the component filters, three new algorithms to adapt the mixing parameter were proposed and analyzed. Using the analysis results of these algorithms in conjunction with the results of the transient analysis of adaptive filters, the transient behavior of the affine combination was analyzed. Through simulations, a good agreement between analytical and experimental results was always observed. In the blind equalization case, a combination of two CMA equalizers with different initializations was also proposed. The simulation results suggest that the affine combination can avoid local minima of the constant modulus cost function.

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Renato_Candido.pdf (3.08 Mbytes)
Publishing Date
2009-07-14

WARNING: The material described below relates to works resulting from this thesis or dissertation. The contents of these works are the author's responsibility.
• CANDIDO, Renato, SILVA, Magno Teófilo Madeira da, and NASCIMENTO, Vítor Heloiz. Transient and steady-state analysis of the affine combination of two adaptive filters [doi:10.1109/TSP.2010.2048210]. IEEE Transactions on Signal Processing [online], 2010, vol. 58, p. 4064-4078.
• CANDIDO, Renato, et al. A statistical analysis of the dual-mode CMA [doi:10.1109/ISCAS.2010.5537119]. In IEEE International Symposium on Circuits and Systems, Paris, 2010. Proceedings of ISCAS'2010., 2010.
• CANDIDO, Renato, et al. Análise estatística do algoritmo Shalvi-Weinstein. In Simpósio Brasileiro de Telecomunicações - SBrT 2009, Blumenau, 2009. Anais do SBrT 2009., 2009.
• CANDIDO, Renato, SILVA, Magno Teófilo Madeira da, and NASCIMENTO, Vítor Heloiz. Affine Combinations of Adaptive Filters [doi:10.1109/ACSSC.2008.5074399]. In 42nd Annual Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, 2008. Proceedings of Asilomar-2008., 2008.
• CANDIDO, Renato, SILVA, Magno Teófilo Madeira da, and NASCIMENTO, Vítor Heloiz. On Combinations of CMA Equalizers [doi:10.1109/ICASSP.2009.4960221]. In IEEE International Conference on Acoustics, Speech and Signal Processing, Taipei, 2009. Proceedings of ICASSP'2009., 2009.
• CANDIDO, Renato, SILVA, Magno Teófilo Madeira da, e NASCIMENTO, Vítor Heloiz. Uma combinação afim de dois equalizadores autodidatas adaptados com o CMA. In Simpósio Brasileiro de Telecomunicações - SBrT 2008, Rio de Janeiro, 2008. Anais do SBrT 2008., 2008.
• NASCIMENTO, Vítor Heloiz, et al. A transient analysis for the convex combination of adaptive filters [doi:10.1109/SSP.2009.5278642]. In IEEE Workshop on Statistical Signal Processing (SSP2009), Cardiff, 2009. Proceedings of SSP'2009., 2009.
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