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US 5,479,419 AGranted
Adaptive maximum likelihood sequence estimator
AssigneeOki Electric Industry Co., Ltd.
InventorsToshimichi Naoi, Haruhiro Shiino, Yasuo Shoji
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Abstract
An adaptive maximum likelihood sequence estimator includes a channel estimator and a Viterbi algorithm processor for estimating the maximum likelihood transmission symbol sequences. The algorithm processor includes a branch metric computer in which common components are found from regularity in computations of coded alphabets of the transmission symbols and are used for all branch metric computation to reduce the total amount of the operations. Such effective computations are implemented by either of hardware and software in accordance with the constitution of the system of the adaptive maximum likelihood sequence estimator.
Claims24
An adaptive maximum likelihood sequence estimator comprising:
- a transmission channel estimator for estimating, using partial sequences of sampled values of received signals and using estimated values of parts of sequences of transmission symbols, the impulse response of a transmission channel;
- and
- a Viterbi algorithm processor for sequentially estimating the sequences of transmission symbols from the estimated impulse response of the transmission channel and the partial sequences of sampled values, said Viterbi algorithm processor including a branch metric computer, an addition-comparison-selection portion, a path metric memory, and a path history memory;
- said branch metric computer including
- common element operation means for computing operational common elements which commonly appear in computations of plural branch values when all branch values for connecting between states are to be computed, in association with a regularity of coded alphabets of transmission symbols,
- branch value producing means for producing all branch values from the computed common elements, and
- branch metric final operation means for computing all branch metrics from the produced branch values.
4 more elements
An adaptive maximum likelihood sequence estimator comprising:
- a transmission channel estimator for estimating, using partial sequences of sampled values of received signals and using estimated values of parts of sequences of transmission symbols, the impulse response of a transmission channel;
- and
- a Viterbi algorithm processor for sequentially estimating the sequences of transmission symbols from the estimated impulse response of the transmission channel and the partial sequences of sampled values, said Viterbi algorithm processor including a branch metric computer, an addition-comparison-selection portion, a path metric memory, and a path history memory;
- wherein said branch metric computer computes, in association with a regularity of coded alphabets of transmission symbols, operational common elements that commonly appear in computations of plural branch values when all branch values for connecting between states are to be computed, produces all branch values from the computed common elements, and computes all branch metrics from produced branch values.
1 more element
An adaptive maximum likelihood sequence estimator comprising:
- a transmission channel estimator for estimating, using partial sequences of sampled values of received signals and using estimated values of parts of sequences of transmission symbols, the impulse response of a transmission channel;
- and
- a Viterbi algorithm processor for sequentially estimating the sequences of transmission symbols from the estimated impulse response of the transmission channel and the partial sequences of sampled values, said Viterbi algorithm processor including a branch metric computer, an addition-comparison-selection portion, a path metric memory, and a path history memory;
- said branch metric computer including
- common element operation means for computing one or more kinds of operational common elements which commonly appear in computations of plural branch metrics when branch metrics of all branches for connecting between states are to be computed, in association with a regularity of coded alphabets of transmission symbols, and
- branch metric final operation means for computing all branch metrics from the computed common elements.
3 more elements
An adaptive maximum likelihood sequence estimator comprising:
- a transmission channel estimator for estimating, using partial sequences of sampled values of received signals and using estimated values of parts of sequences of transmission symbols, the impulse response of a transmission channel;
- and
- a Viterbi algorithm processor for sequentially estimating the sequences of transmission symbols from the estimated impulse response of the transmission channel and the partial sequences of sampled values, said Viterbi algorithm processor including a branch metric computer, an addition-comparison-selection portion, a path metric memory, and a path history memory;
- wherein said branch metric computer computes, in association with a regularity of coded alphabets of transmission symbols, one or more kinds of operational common elements that commonly appear in computations of plural branch metrics when branch metrics of all branches for connecting between states are to be computed, and computes all branch metrics from the computed common elements.
1 more element
Dependencies are inferred from the claim text.