Pulse or digital communications – Receivers – Particular pulse demodulator or detector
Patent
1993-06-23
1997-01-21
Chin, Stephen
Pulse or digital communications
Receivers
Particular pulse demodulator or detector
375355, H04L 2706, H03D 100
Patent
active
055966071
ABSTRACT:
In a digital time-shared transmission system, a receiver receives a signal whose symbol rate is lower than the channel bandwidth of the system. A correlating and sampling circuit receives a baseband signal, samples the signal a number of times with each symbol time, performs channel correlation, generates a channel estimate and samples down the once sampled signal to an observed signal with two values for each symbol time. A channel equalizer executes a fractional viterbi algorithm which utilizes two delta-metric values for each state transition and generates estimated symbols. A channel estimating filter receives a symbol sequence of alternating zero-value symbols and the estimated symbols and generates an estimated signal. The channel estimating filter is adapted with the aid of an error signal and the filter delivers a channel estimate to the channel equalizer. Weighting factors are generated with the aid of the error signal and the two aforementioned delta-metric values are co-weighted to a common delta-metric value with the aid of weighting factors, this common delta-metric value being used to generate the estimated symbols. The use of the weighting factors improves the metric calculation and enables the channel estimating filter and the channel equalizer to be relatively simple. The insertion of the zero-value symbols simplifies the generation of the weighting factors and the adaptation of the channel estimating filter.
REFERENCES:
patent: 5031193 (1991-07-01), Atkinson et al.
patent: 5048059 (1991-09-01), Dent
patent: 5091918 (1992-02-01), Wales
patent: 5164961 (1992-11-01), Gudmundson
patent: 5191598 (1993-03-01), Backstrom et al.
patent: 5228057 (1993-07-01), Larsson
patent: 5263053 (1993-11-01), Wan et al.
patent: 5285480 (1994-02-01), Chennakeshu et al.
patent: 5313495 (1994-05-01), Kim
G. Forney, Jr., "The Viterbi Algorithm," Proceedings of the IEEE, vol. 61, No. 3, pp. 268-278 (Mar. 1973).
R. Iltis, "A Bayesian Maximum-Likelihood Sequence Estimation Algorithm for A-Priori Unknown Channels and Symbol Timing," Dept. of Electrical and Computer Engineering, University of California, Santa Barbara, pp. 1-26 (Aug. 21, 1990).
F. Magee et al., "Adaptive Maximum-Likelihood Sequence Estimation for Digital Signalling 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., New Jersey, pp. 408-411 (May 18-20, 1993).
S. Qureshi, "Adaptive Equalization," Proceedings of the IEEE, vol. 73, No. 9, pp. 1370-1373 (Sep. 1985).
G. Ungerboeck, "Adaptive Maximum-Likelihood Receiver for Carrier-Modulated Data-Transmission Systems," IEEE Trans. on Communications, vol. COM-22, No. 5, pp. 621-636 (May 1974).
Y. Wan et al., "A Fractionally-Spaced Maximum-Likelihood Sequence Estimation Receiver in a Multipath Fading Environment," Proc. ICASSP, pp. IV-689 to IV-692, IEEE (1992).
S. Chennakesu et al., "Differential Detection of .pi./4-Shifted-DQPSK for Digital Cellular Radio", IEEE, 1991, pp. 186-191.
A. P. Clark et al, "Adaptive Channel Estimator for an HF Radio Link", IEEE Trans. on Commun., vol. 37, No. 9, Sep. 1989, pp. 918-926.
M. V. Eyuboglu et al, "Reduced-State Sequence Estimation with Set Partitioning and Decision Feedback", IEEE Trans. on Commun., vol. 36, No. 1, Jan. 1988, pp. 13-20.
W. C. Y. Lee, Mobile Communications Engineering, McGraw-Hill Book Co., 1982, pp. 291-336.
Q Liu et al., "An Adaptive Maximum-likelihood Sequence Estimation Receiver with Dual Diversity Combining/Selection", IEEE, 1992, pp. 245-249.
Q. Liu et al., "A Unified MLSE Detection Technique for TDMA Digital Cellular Radio", IEEE, 1993, pp. 265-268.
J. G. Proakis, Digital Communications, McGraw-Hill Book Company, 1989, pp. 554-643.
W. H. Sheen et al., "MLSE Equalization and Decoding for Multipath-Fading Channels", IEEE Trans. on Commun., vol. 39, No. 10, Oct. 1991, pp. 1455-1464.
Gudmundson Perols B. O.
Jamal Karim
Larsson Lars G.
Chin Stephen
Phan Hai H.
Telefonaktiebolaget LM Ericsson
LandOfFree
Method and an arrangement of estimating transmitted symbols at a 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 an arrangement of estimating transmitted symbols at a, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and an arrangement of estimating transmitted symbols at a will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2330350