US4888775A
Expired / Lapsed
US
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Trellis codes for partial response channels
Assignee: International Business Machines Corp
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Filing: 1988-03-18
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Granted: 1989-12-19
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Expires: 2008-03-18
Abstract
Abstract An improved method is described for coding input strings to improve reliability of partial response channels. This method comprises encoding an input string into an intermediate string using a binary convolutional code, and encoding the intermediate string using a nonlinear inner code that repeats and inverts selected bits of the intermediate string. The inner code has a coding rate of less than one. As specifically illustrated, this method provides coding gains for partial response channels of at least 4.8 dB.
Inventors
- 👤 Razmik Karabed
- 👤 Paul H. Siegel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:32
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/4906; H04L25/4908; H04L25/4915; H04L25/497
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
63 words
A method for coding input strings to improve reliability of partial response channels, comprising the steps of: (a) encoding an input string into an intermediate string using a binary convolution code; and (b) encoding said intermediate string using a nonlinear inner code that repeats and inverts selected bits of said intermediate string; said inner code having a coding rate of less than one.
Claim 2
Independent Claim
63 words
A method for coding input strings to improve reliability of partial response channels, comprising the steps of: (a) encoding an input string into an intermediate string using a binary convolution code; and (b) encoding said intermediate string using a nonlinear inner code that repeats and inverts selected bits of said intermediate string; said inner code having a coding rate of less than one.
Claim 3
Dependent Claim
52 words
A method according to claim 1, including steps of: concatenating the convolutional code and inner code to produce a combined code rate, the magnitude of which is the product of the convolutional code rate and inner code rate; and modifying the convolutional code rate and/or inner code rate, for improving coding gain.
Claim 4
Dependent Claim
24 words
A method according to claim 1, wherein coding gain is at least 4.8 dB and maximum zero run length (ZRL) does not exceed 3.
Claim 5
Dependent Claim
16 words
A method according to claim 1, wherein both the inner code and the channels are interleaved.
Claim 6
Dependent Claim
19 words
A method according to claim 1, including the step of employing a channel transfer polynomial of (1-D N ).
Claim 7
Dependent Claim
10 words
A method according to claim 5, wherein N is 2.
Claim 8
Dependent Claim
19 words
A method according to claim 1, including the step of employing a channel transfer polynomial of (1+D N ).
Claim 9
Dependent Claim
40 words
A method according to claim 1, including concatenating an inner code of rate 1/2 on a (1±D) channel with rate 1 convolutional code to provide a combined code with rate 1/2 and a maximum zero run length (ZRL) of 1.
Claim 10
Dependent Claim
39 words
A method according to claim 1, including concatenating an inner code of rate 2/3 on a (1±D) channel with rate 3/4 convolutional code to provide a combined code with rate 3/6 and maximum zero run length (ZRL) of 2.
Claim 11
Dependent Claim
39 words
A method according to claim 1, including concatenating an inner code of rate 3/4 on a (1±D) channel with rate 2/3 convolutional code to provide a combined code with rate 2/4 and maximum zero run length (ZRL) of 3.
Claim 12
Dependent Claim
39 words
A method according to claim 1, including concatenating an inner code of rate 5/8 on a (1±D) channel with rate 4/5 convolutional code to provide a combined code with rate 4/8 and maximum zero run length (ZRL) of 3.
Claim 13
Dependent Claim
25 words
A method according to claim 1, including concatenating the inner code with a convolutional code to provide a combined code rate of less than 1/2.
Claim 14
Dependent Claim
25 words
A method according to claim 1, including steps of: interleaving the inner code; and employing a channel transfer polynomial of (1+D-D 2 -D 3 ).
Claim 15
Dependent Claim
13 words
A method according to claim 1, wherein the inner code rate is one-half.
Claim 16
Dependent Claim
41 words
A method according to claim 1, including concatenating an inner code of rate 1/2 on a (1-D)(1+D) 2 channel with optimal rate 1 code to provide an interleaved biphase rate 2/4 code with a coding gain of at least 4.8 dB.
References Cited (Backward Citations)
US4707681A
Cited
US4786890A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-18 | 1993-06-19 | 1993-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-18 | 1997-06-19 | 1997-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-18 | 2001-06-19 | 2001-12-19 | $7700.00 | Window Closed / Lapsed |