Pulse or digital communications – Repeaters – Testing
Patent
1991-09-03
1994-02-01
Chin, Stephen
Pulse or digital communications
Repeaters
Testing
3647242, H03H 730
Patent
active
052838110
ABSTRACT:
An adaptive Decision Feedback Equalizer (DFE) (40) for a digital cellular mobile radio channel demodulator (30) employs a Complex Fast-Kalman Adaptation algorithm (56) to track channel variations. Sensitivity to sample timing jitter is reduced by providing the DFE with fractionally spaced feed-forward taps (50'). Deficiencies inherent in using a reduced precision implementation are overcome by adding a dither signal to sets of operations in the algorithm, the dither signal comprising an appropriately selected Gaussian random variable. For small delay spreads of approximately one third of a symbol duration or less, a resulting degradation in Bit Error Rate is avoided by switching the DFE out of the circuit or by reducing the number of taps of the DFE. For delay spreads of less than 40 microseconds and greater than approximately 10 microseconds, a (2,3) fractionally spaced DFE provides an adequate compromise between complexity and performance.
REFERENCES:
patent: 4852090 (1989-07-01), Borth
patent: 5068873 (1991-11-01), Murakami
"Fractionally-Spaced Equalization: An Improved Digital Transversal Equalizer", R. D. Gitlin et al., The Bell System Technical Journal, vol. 60, No. 2 Feb. 1981 pp. 275-296.
"Sensitivity Analysis of Transversal RLS Algorithms with Correlated Inputs", S. Ardalan et al., IEEE Iternational Symposium on Circuits and Systems, Portland, Oreg., May 1989.
Adaptive Filter Theory, Chapter 8, Prentice Hall, Englewood Cliffs, N.J., 1986, S. Haykin.
"An Adaptive MLSE Receiver for TDMA Digital Mobile Radio", R. D'Avella, et al., IEEE, vol. 7, No. 1, Jan. 1989, pp. 122-129.
"Adaptive Lattice Decision-Feedback Equalizers-Their Performance and Application to Time-Variant Multipath Channels", IEEE Trans. Comm. vol. COM-33, No. 4, pp. 348-356. F. Ling et al.
"Application of Fast Kalman Estimation to Adaptive Equalization", D. Falconer et al., IEEE Transactions on Communications, vol. COM-26, No. 10, Oct. 1978, pp. 1439-1446.
"Adaptive Maximum-Likelihood Receiver for Carrier-Modulated Data-Transmission Systems", G. Underboeck, IEEE Transactions on Communications, vol. COM-22, No. 5, May 1974, pp. 624-636.
"Results on Fast-Kalman and Viterbi Adaptive Equalizers for Mobile Radio with CEPT/GSM System Characteristics", Proc. of IEEE Globecom., pp. 26.3.1-26.3.5., 1988.
"Bit Synchronization and Timing Sensitivity in Adaptive Viterbi Equalizers for Narrowband-TDMA Digital Mobile Systems", A. Baier et al., IEEE Vehicular Technology Conference, Philadelphia, Pa., pp. 377-384, 1988.
"Design and Performance of Synchronization Techniques and Viterbi Adaptive Equalizers for Narrowband TDMA Mobile Radio", G. D'Aria et al., 3rd Nordic Seminar on Digital Land Mobile Radio Comm., Copenhagen, Denmark, Sep. 13-15, 1988.
S. Chennakeshu et al., "Decision Feedback Equalization for Digital Cellular Radio", IEEE International Communications Conference, Atlanta, Ga., Apr. 1990, pp. 1492-1496.
Anderson John B.
Chennakeshu Sandeep
Narasimhan Anand
Bocure Tesfaldet
Chin Stephen
General Electric Company
Snyder Marvin
LandOfFree
Decision feedback equalization for digital cellular radio does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Decision feedback equalization for digital cellular radio, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Decision feedback equalization for digital cellular radio will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-584830