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http://dx.doi.org/10.5573/ieie.2016.53.7.003

A Modified Decision-Directed LMS Algorithm  

Oh, Kil Nam (Dept. of Healthcare &Medical Engineering, Gwangju University)
Publication Information
Journal of the Institute of Electronics and Information Engineers / v.53, no.7, 2016 , pp. 3-8 More about this Journal
Abstract
We propose a modified form of the decision-directed least mean square (DD LMS) algorithm that is widely used in the optimization of self-adaptive equalizers, and show the modified version greatly improves the initial convergence properties of the conventional algorithm. Existing DD LMS regards the difference between a equalizer output and a quantization value for it as an error, and achieves an optimization of the equalizer based on minimizing the mean squared error cost function for the equalizer coefficients. This error generating method is useful for binary signal or a single-level signals, however, in the case of multi-level signals, it is not effective in the initialization of the equalizer. The modified DD LMS solves this problem by modifying the error generation. We verified the usefulness and performance of the modified DD LMS through experiments with multi-level signals under distortions due to intersymbol interference and additive noise.
Keywords
modified decision-directed; LMS; error signal; cost function; multi-level signal; CMA;
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  • Reference
1 R.W. Lucky, "Techniques for adaptive equalization of digital communication systems," Bell System Tech. J., vol. 45, no. 2, pp. 255-286, Feb. 1966.   DOI
2 B. Widrow and M.E. Hoff, Jr., "Adaptive switching circuits," IRE WESCON Convention Record, Pt. 4, pp. 96-104. Aug. 1960.
3 B. Widrow, J.R. Glover, Jr., J.M. McCool, J. Kaunitz, C.S. Williams, R.H. Hearn, J.R. Zeidler, E. Dong, Jr., and R.C. Goodlin, "Adaptive noise cancelling: Principles and applications," Proc. IEEE, vol. 63, no. 12, pp. 1692-1716, Dec. 1975.   DOI
4 B. Widrow and S.D. Stearns, Adaptive signal processing, Englewood Cliffs, NJ: Prentice-Hall, 1985.
5 R.W. Lucky, J. Salz, and E.J. Weldon, Principles of data communication, New York: McGraw-Hill, 1968.
6 S. Haykin, ed., Unsupervised adaptive filtering volume 2: Blind deconvolution, New York: John Wiley & Sons, 2000.
7 J.R. Treichler, C. Richard Johnson, and M.G. Larimore, Theory and design of adaptive filters, New York: John Wiley & Sons, 1987.
8 B. Widrow, J. McCool, and M. Ball, "The complex LMS algorithm," Proc. IEEE, vol. 63, no. 4, pp. 719-720, Apr. 1975.   DOI
9 D.N. Godard, "Self-recovering equalization and carrier tracking in two-dimensional data communication systems," IEEE Trans. Commun., vol. 28, no. 11, pp. 1867-1875, Nov. 1980.   DOI
10 G. Picchi and G. Prati, "Blind equalization and carrier recovery using a "Stop-and-Go" decision-directed algorithm," IEEE Trans. Commun., vol. 35, no. 9, pp. 877-887, Sep. 1987.   DOI
11 D. Hatzinakos and C.L. Nikias, "Estimation of multipath channel response in frequency selective channels," IEEE J. Selected Areas in Communications, vol. 7, no. 1, pp. 12-19, Jan. 1989.   DOI