DC offset correction for constant modulus equalization

Details DC offset correction for constant modulus equalization DC offset correction for constant modulus equalization

2008-03-25

2008-03-25

Bayard, Emmanuel (Department: 2611)

Pulse or digital communications

Equalizers

Automatic

Reexamination Certificate

active

07349469

ABSTRACT:
A single-axis receiver processes, for example, a complex vestigial sideband (VSB) modulated signal with an equalizer accounting for DC offset within the modulated signal. The DC offset embedded in a received signal may degrade the process of equalization. The equalizer includes a method of blind estimation of the DC offset for removing the DC offset. The estimate is generated by jointly minimizing a Constant Modulus (CM) cost function over equalizer parameters and a DC offset estimate. An arbitrary DC offset the CM cost function admits local spurious minima in terms of the equalizer function. If the DC offset at the receiver is equal to the DC offset inserted at the transmitter, which is equivalent to neglecting the ISI caused by the channel, then only half of the CM equalizer minima remain unchanged. Provided a power constraint on the signal space is satisfied, the DC offset estimate, computed with a joint optimization of the CM cost function, converges to the desired solution, and, thus, the equalizer parameters are guaranteed to converge to the desired solution.

REFERENCES:
patent: 5777692 (1998-07-01), Ghosh
patent: 5822380 (1998-10-01), Bottomley
patent: 5872815 (1999-02-01), Strolle et al.
patent: 5909466 (1999-06-01), Labat et al.
patent: 6108517 (2000-08-01), Arslan et al.
patent: 6314147 (2001-11-01), Liang et al.
patent: 6504884 (2003-01-01), Zvonar
patent: 6650716 (2003-11-01), Ratnarajah
patent: 7058144 (2006-06-01), Baldwin
“The Performance of Staggered Quadrature Amplitude Modulation in the Presence of Phase Jitter” by Richard D. Gitlin and Edmond Y. Ho, IEEE Transactions On Communications, vol. COM-23, No. 3, Mar. 1975, pp. 348-352.
“Timing Recovery In Digital Synchronous Data Recovery” by Kurt H. Mueller and Markus Miller, IEEE Transactions On Communications, vol. Com-24, No. 5, May 1976, pp. 516-531.
“Practical Blind Demodulators For High-Order QAM Signals” by John R. Treichler, Michael G. Larimore and Jeffrey C. Harp, Proceedings of the IEEE, vol. 86, No. 10, Oct. 1998, pp. 1907-1926.
“Blind Equalization Using the Constant Modulus Criterion: A Review” by C. Richard Johnson, Jr., et al, Proceedings of the IEEE, vol. 86, No. 10, Oct. 1998, pp. 1927-1950.
“Global Convergence Of A Single-Axis Constant Modulus Algorithm” by A. Shah, S. Biracree, R. A. Casas, T. J. Endres, S. Hulyalkar, T. A. Schaffer and C. H. Strolle, Technical Memo, NxtWave Communications, Langhorne, PA.
“A New Approach to Multipath Correction Of Constant Modulus Signals” by John R. Treichler and Brian G. agee, IEEE Transactions On Acoustics, Speech And Signal Processing, vol. ASSP-31, No. 2, Apr. 1983, pp. 459-471.
“Uniqueness Of The Maximum Likelihood Estimates Of The Parameters Of An ARMA Model” by Karl J. Åström and Torsten Söderströ{umlaut over ( )}m, IEEE Transactions On Automatic Control, Dec. 1974, pp. 769-773.
“Digital Communication,” Lee and Messerschmitt, Appendix 17-B, Kluwer Academic Publishers, Norwell, MA, Second Edition, 1994.
“Self-Recovering Equalization and Carrier Tracking in Two-Dimensional Data Communication Systems” by D. N. Godard, IEEE Transactions on Communications, vol. 28, No. 11, pp. 1867-1875, Oct. 1980.
“Blind Deconvolution,” by Simon Haykin, Chapter 2, Prentice Hall, Englewood Cliffs, NJ, 1994, pp. 8-59.
“Phase recovery based on minimization of Single-Axis Constant Modulus criterion: Performance analysis” by A. Touzni, et al., 2001 Conference on Information Sciences and Systems, The John Hopkins University, Mar. 21-23, 2001.
“Adaptive Fractionally Spaced Blind Equalization” by I. Fijalkow, F. Lopez de Victoria and C. R. Johnson Jr., 1994 IEEE, pp. 257-260.

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