Pulse or digital communications – Receivers – Interference or noise reduction
Patent
1995-10-06
1998-03-10
Bocure, Tesfaldet
Pulse or digital communications
Receivers
Interference or noise reduction
375350, 375232, 375341, H04B 710, H04L 102
Patent
active
057270325
ABSTRACT:
In a digital signal transmission system, a receiver receives a signal, wherein the signal bandwidth of the system exceeds the system symbol rate. A correlation and sampling circuit receives a baseband signal, samples the signal eight times per symbol time, correlates, generates a channel estimate and down-samples the sampled signal to form an observed signal. This signal is filtered in a prefilter, whose output is sampled at symbol rate and the obtained signal is delivered to a channel equalizer which performs a viterbi algorithm with non-quadratic metric calculation and generates estimated symbols. A channel estimation filter receives a symbol sequence which contains alternate zero-value symbols and the estimated symbols and generates an estimated signal. An error signal is generated and used to adapt the channel estimate and also to generate weight factors. The coefficients of the prefilter are generated as a function of the channel estimate and the weight factors. Coefficients are generated in a metric calculation filter, by convolving the channel estimate with the prefilter and are used to generate the estimated symbols. The transmission channel, excluding the prefilter, is estimated explicitly so as to enable fast channel changes to be followed. The use of the weight factors enables a short channel estimate to be used. The insertion of the zero-value symbols simplifies adaptation of the channel estimate.
REFERENCES:
patent: 4885757 (1989-12-01), Provence
patent: 5164961 (1992-11-01), Gudmundson
patent: 5199047 (1993-03-01), Koch
patent: 5202903 (1993-04-01), Okanoue
patent: 5204878 (1993-04-01), Larsson
patent: 5228057 (1993-07-01), Larsson
patent: 5319677 (1994-06-01), Kim
E. Dahlman, "A Study of Adaptive Detectors for Fast-Varying Mobile-Radio Channels," Report No. TRITA-TTT-9213, Section 5, Royal Institute of Technology (Oct. 19, 1992).
G. D. Forney, Jr., "The Viterbi Algorithm," Proc. of the IEEE, vol. 61, No. 3, pp. 268-278 (Mar. 1973).
R. A. Iltis, "A Bayesian Maximum-Likelihood Sequence Estimation Algorithm for A-Priori Unknown Channels and Symbol Timing," Department of Electrical and Computer Engineering, University of California, Santa Barbara (Aug. 21, 1990).
L. Lindbom, "Adaptive Equalization for Fading Mobile Radio Channels," Chap. 4, Rpt. No. UPTEC 92124R, Institute of Technology, Uppsala University (Nov. 1992).
F. R. Magee, Jr. et al., "Adapative Maximum-Likelihood Sequence Estimation for Digital Signaling in the Presence of Intersymbol Interference," IEEE Trans. on Information Theory, pp. 120-124 (Jan. 1973).
K. Okanoue et al., "New MLSE Receiver Free From Sample Timing and Input Level Controls," 43rd IEEE Vehicular Technology Conf., pp. 408-411 (May 18-20, 1993).
S.U.H. Qureshi, "Adaptive Equalization," Proc. of the IEEE vol. 73, No. 9, pp. 1370-1372 (Sep. 1985).
G. Ungerboeck, "Adaptive Maximum-Likelihood Receiver for Carrier-Modulated Data-Transmission Systems," IEEE Trans. on Communications, vol. COM-22, No. 5, pp. 624-636 (May 1974).
Y. Wan et al., "A Fractionally-Spaced Maximum-Likelihood Sequence Estimation Receiver in a Multipath Fading Enviroment," Proc. of the IEEE, ICASSP, pp. 689-692 (1992).
Brismark Gustav
Gudmundson Bjorn
Jamal Karim
Bocure Tesfaldet
Telefonaktiebolaget LM Ericsson
LandOfFree
Method and device for estimating transmitted signals in a receiv does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for estimating transmitted signals in a receiv, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for estimating transmitted signals in a receiv will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-146324