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US5327439A
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Efficiency of the Viterbi algorithm
Assignee: Nokia Oyj
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Filing: 1990-12-28
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Granted: 1994-07-05
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Expires: 2010-12-28
Abstract
Abstract The efficiency of a Viterbi algorithm in a communication system, in which the transmission channel contains memory, is improved when several sequences in a signal string are detected in descending probability order. An error detecting operation then selects the correct sequence, if any, to be the received sequence.
Inventors
- 👤 Kari P. Estola
- 👤 Harri A. Jokinen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:52
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03178; H03; H03M; H03M13/00; H03M13/37; H03M13/39; H03M13/41; H04L25/0202; H04L25/0212; H04L25/0216
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
115 words
A method for improving efficiency of a Viterbi algorithm in a system receiving a signal string via a transmission channel having memory of at least part of a previous signal, comprising the steps of: detecting, by using the Viterbi algorithm, a most probable sequence in said signal string; detecting, by using an extension of the Viterbi algorithm, several additional sequences in said received signal string in descending probability order; performing an error detection operation on all of said detected sequences until one of an error-free sequence and the sequence with the least number of errors is detected by the error detection operation as the best sequence; and selecting the best sequence as a received sequence.
Claim 2
Independent Claim
115 words
A method for improving efficiency of a Viterbi algorithm in a system receiving a signal string via a transmission channel having memory of at least part of a previous signal, comprising the steps of: detecting, by using the Viterbi algorithm, a most probable sequence in said signal string; detecting, by using an extension of the Viterbi algorithm, several additional sequences in said received signal string in descending probability order; performing an error detection operation on all of said detected sequences until one of an error-free sequence and the sequence with the least number of errors is detected by the error detection operation as the best sequence; and selecting the best sequence as a received sequence.
Claim 3
Dependent Claim
37 words
Method according to claim 1, wherein the sequences detected by said extended algorithm are stored in a memory device, from which memory device the stored sequences are read out to be processed in the error detection operation.
Claim 4
Dependent Claim
13 words
The method of claim 2, wherein said system is a data communication system.
Claim 5
Dependent Claim
37 words
Method according to claim 1, wherein error detection is immediately performed on a sequence detected by said extended algorithm and error detection is repeated on said sequences in descending probability order until an error-free sequence is found.
Claim 6
Dependent Claim
13 words
The method of claim 4, wherein said system is a data communication system.
Claim 7
Dependent Claim
13 words
The method of claim 1, wherein said system is a data communication system.
Claim 8
Dependent Claim
16 words
The method of claim 6, wherein said communication system is a pan-European digital mobile telephone system.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-07-04 | 1998-01-03 | 1998-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-07-04 | 2002-01-03 | 2002-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-07-04 | 2006-01-03 | 2006-07-05 | $7700.00 | Window Closed / Lapsed |