US5539757A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Error correction systems with modified Viterbi decoding
Assignee: AT&T Inc
•
Filing: 1993-12-22
•
Granted: 1996-07-23
•
Expires: 2013-12-22
Abstract
Abstract In a communications system, a convolutional encoder encodes data from a data source and a modified Viterbi decoder decodes the encoded data after the encoded dated passes through an error producing channel. The decoder calculates selected metric increments, known as kernel metric increments, for half the states, and selects survivor metrics for all states.
Inventors
- 👤 Richard V. Cox
- 👤 Reed Thorkildsen
- 👤 Yong Zhou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:17
CPC Classifications
H; H03; H03M; H03M13/00; H03M13/37; H03M13/39; H03M13/41; H03M13/4161; H03M13/3961; H03M13/4107; H03M13/65; H03M13/6502; H03M13/6569; H03M13/6577; H03M13/6583; H04; H04L; H04L1/00; H04L1/004; H04L1/0045; H04L1/0054
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
121 words
A communication system, comprising: a channel; a modulator at one end of the channel and a demodulator at the other end of the channel; a convolutional encoder having a constant length K and N=2.sup.(K-1) states and responsive to a data source and coupled to the modulator; a modified Viterbi decoder coupled to said demodulator; said decoder including means for reading successive words from the demodulator; said decoder including means for calculating kernel metric increments for only N/2 states; said decoder including selector means for comparing accumulative metrics for each metric increment and selecting survivors for two new states; and tracing means in said decoder for tracing back from a zero state; said calculating means being for calculating up to N/2 metrics.
Claim 2
Dependent Claim
121 words
A communication system, comprising: a channel; a modulator at one end of the channel and a demodulator at the other end of the channel; a convolutional encoder having a constant length K and N=2.sup.(K-1) states and responsive to a data source and coupled to the modulator; a modified Viterbi decoder coupled to said demodulator; said decoder including means for reading successive words from the demodulator; said decoder including means for calculating kernel metric increments for only N/2 states; said decoder including selector means for comparing accumulative metrics for each metric increment and selecting survivors for two new states; and tracing means in said decoder for tracing back from a zero state; said calculating means being for calculating up to N/2 metrics.
Claim 3
Dependent Claim
77 words
A modified Viterbi decoder for decoding from a channel, encoded words in code having a constant length K and N=2.sup.(K-1) words, comprising: means for reading words from the channel; means for calculating kernel metric increments for only N/2 states; selector means for comparing accumulative metrics for each metric increment and selecting survivors for two new states; and tracing means for tracing back from a zero state; said calculating means being for calculating up to N/2 metric increments.
Claim 4
Dependent Claim
77 words
A modified Viterbi decoder for decoding from a channel, encoded words in code having a constant length K and N=2.sup.(K-1) words, comprising: means for reading words from the channel; means for calculating kernel metric increments for only N/2 states; selector means for comparing accumulative metrics for each metric increment and selecting survivors for two new states; and tracing means for tracing back from a zero state; said calculating means being for calculating up to N/2 metric increments.
Claim 5
Independent Claim
101 words
A method of processing information, comprising the following steps: encoding data from a data source in a convolutional decoder; modulating the encoded data; passing the modulated and encoded data through a data channel; demodulating the data from the channel; decoding the demodulated data with a modified Viterbi decoder; the decoding step including reading successive total of N states of successive words from the demodulator; the decoding step further including calculating kernel metric increments for only N/2 metrics in said decoder; said decoding step further including comparing metrics and selecting survivors for two new states; and tracing back from a first state.
Claim 6
Independent Claim
101 words
A method of processing information, comprising the following steps: encoding data from a data source in a convolutional decoder; modulating the encoded data; passing the modulated and encoded data through a data channel; demodulating the data from the channel; decoding the demodulated data with a modified Viterbi decoder; the decoding step including reading successive total of N states of successive words from the demodulator; the decoding step further including calculating kernel metric increments for only N/2 metrics in said decoder; said decoding step further including comparing metrics and selecting survivors for two new states; and tracing back from a first state.
Claim 7
Independent Claim
47 words
A method of processing encoded data, comprising: reading a successive total of N states of successive words in the data; calculating kernel metric increments for only N/2 metrics in the words; comparing metrics and selecting survivors for two new states; and tracing back from a first state.
Claim 8
Independent Claim
47 words
A method of processing encoded data, comprising: reading a successive total of N states of successive words in the data; calculating kernel metric increments for only N/2 metrics in the words; comparing metrics and selecting survivors for two new states; and tracing back from a first state.
References Cited (Backward Citations)
US4240156A
Cited
US4631735A
Cited
US4660214A
Cited
US4777636A
Cited
US5181209A
Cited
US5111483A
Cited
US5208816A
Cited
US5193094A
Cited
US5243605A
Cited
US5229767A
Cited
US5291499A
Cited
US5257272A
Cited
US5280489A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-07-23 | 2000-01-22 | 2000-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-23 | 2004-01-22 | 2004-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-23 | 2008-01-22 | 2008-07-23 | $7700.00 | Window Closed / Lapsed |