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Two Blind Adaptive Equalizers Connected in Series for Equalization Performance Improvement

DOI: 10.4236/jsip.2013.41008, PP. 64-71

Keywords: Blind Adaptive Equalizers, Blind Adaptive Deconvolution, Equalization Performance, Variable Step-Size

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Abstract:

A variable step-size parameter is usually used to accelerate the convergence speed of a blind adaptive equalizer with N1 + N2 -1 coefficients where N1 and N2 are odd values. In this paper we show that improved equalization performance is achieved when using two blind adaptive equalizers connected in series where the first and second blind adaptive equalizer have N1 and N2 coefficients respectively compared with the case where a single blind adaptive equalizer is applied with N1 + N2 -1 coefficients. It should be pointed out that the same algorithm (cost function) is used for updating the filter taps for the different equalizers and that a fixed step-size parameter is used. Simulation results show that for the low signal to noise ratio (SNR) environment and for the case where the convergence speed is slow due to the channel characteristics, the new method has a faster convergence speed with a factor of approximately two while leaving the system with approximately the same or lower residual intersymbol interference (ISI).

References

[1]  C. Feng and C. Chi, “Performance of Cumulant Based Inverse Filters for Blind Deconvolution,” IEEE Transaction on Signal Processing, Vol. 47, No. 7, 1999, pp. 1922-1936. doi:10.1109/78.771041
[2]  M. Pinchas and B. Z. Bobrovsky, “A Maximum Entropy Approach for Blind Deconvolution,” Signal Processing (Eurasip), Vol. 86, No. 10, 2006, pp. 2913-2931. doi:10.1016/j.sigpro.2005.12.009
[3]  C. L. Nikias, A. P. Petropulu, “Higher-Order Spectra Analysis a Nonlinear Signal Processing Framework,” Chapter 9, Prentice-Hall, Upper Saddle River, 1993, pp. 419-425.
[4]  D. N. Godard, “Self Recovering Equalization and Carrier Tracking in Two-Dimenional Data Communication System,” IEEE Transactions on Communications, Vol. 28, No. 11, 1980, pp. 1867-1875. doi:10.1109/TCOM.1980.1094608
[5]  M. A. Demir and A. Ozen, “A Novel Variable Step Size Adjustment Method Based on Autocorrelation of Error Signal for the Constant Modulus Blind Equalization Algorithm,” Radioengineering, Vol. 21, No. 1, 2012, pp. 37-45.
[6]  R. Hamzehyan, R. Dianat and N. C. Shirazi, “New Variable Step-Size Blind Equalization Based on Modified Constant Modulus Algorithm,” International Journal of Machine Learning and Computing, Vol. 2, No. 1, 2012, pp. 30-34.
[7]  X. Zhang, l. S. Li, D. F. Zhuo and Z. S. Dong, “A New Adaptive Step-Size Blind Equalization Based on Autocorrelation of Error Signal,” 7th International Conference on Signal Processing, Beijing, 31 August-4 September 2004, pp. 1719-1722.
[8]  L. Y. Zhang, L. Chen and Y. S. Sun, “Variable Step-Size CMA Blind Equalization Based on Non-Linear Function of Error Signal,” International Conference on Communications and Mobile Computing, Kunming, 6-8 January 2009, pp. 396-399.
[9]  M. Lazaro, I. Santamaria, D. Erdogmus, K. E. Hild, C. Pantaleon and J. C. Principe, “Stochastic Blind Equalization Based on pdf Fitting Using Parzen Estimator,” IEEE Trans. on Signal Processing, Vol. 53, No. 2, 2005, pp. 696-704. doi:10.1109/TSP.2004.840767
[10]  O. Shalvi and E. Weinstein, “New Criteria for Blind Deconvolution of Nonminimum Phase Systems (Channels),” IEEE Transactions on Information Theory, Vol. 36, No. 2, 1990, pp. 312-321. doi:10.1109/18.52478
[11]  M. Pinchas, “A MSE Optimized Polynomial Equalizer for 16QAM and 64QAM Constellation,” Signal, Image and Video Processing, Vol. 5, No. 1, 2011, pp. 29-37. doi:10.1007/s11760-009-0138-z
[12]  G.-H. Im, C. J. Park and H. C. Won, “A Blind Equalization with the Sign Algorithm for Broadband Access,” IEEE Communication Letters, Vol. 5, No. 2, 2001, pp. 70-72. doi:10.1109/4234.905939
[13]  A. K. Nandi, “Blind Estimation Using Higher-Order Statistics,” Chapter 2, Kluwer Academic, Boston, 1999, pp. 78-79.
[14]  E. A. Lee and D. G. Messerschmitt, “Adaptive Equalization,” In: E. A. Lee and D. G. Messerschmitt, Eds., Digital Communication, 2nd Edition, Kluwer Academic Publisher, Boston, 1997.
[15]  M. Pinchas, “A Closed Approximated Formed Expression for the Achievable Residual Intersymbol Interference Obtained by Blind Equalizers,” Signal Processing Journal (Eurasip), Vol. 90, No. 6, 2010, pp. 1940-1962. doi:10.1016/j.sigpro.2009.12.014

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