US3662338A
Expired / Lapsed
US
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Modified threshold decoder for convolutional codes
Assignee: Radiation Inc
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Filing: 1970-02-01
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Granted: 1972-05-09
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Expires: 1990-02-01
Abstract
Abstract A decoder for convolutional codes utilizes known threshold decoding techniques. The decoder is effective to resolve the dilemma encountered when no majority decision is available in the application of the conventional threshold decoding techniques because the estimates of the information bit to be decoded are equally divided in error and not in error. In those circumstances, the tie vote is broken by utilizing information contained in the received syndrome to specify one of the estimates of the information bit which is in error. By eliminating that estimate, a simple majority vote correctly determines the information bit since the previously encountered even split of the estimates no longer exists. In an alternative decoded arrangement, a set of estimates for each error bit is derived and a threshold decision is made using these estimates, to remove the error bit from the estimate of the information bit. Here, again, ties are resolved by use of information contained in the syndrome of the error pattern.
Inventors
- 👤 Joseph Bibb Cain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:38
CPC Classifications
H; H04; H04L; H04L1/00; H04L1/004; H04L1/0056; H04L1/0059; H03; H03M; H03M13/00; H03M13/37; H03M13/43
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
130 words
A threshold decoder for a digitally coded format of bits containing information and possibly containing transmission errors, comprising means responsive to an incoming format of bits for estimating the value of certain bits in the format, means responsive to the estimates of individual bits for rendering a threshold decision determinative of the information content of successive segments of the format based on the number of estimates in the majority for each segment, means further responsive to the incoming format for calculating the syndrome of a correctable error pattern in the segment of the format under consideration, and means responsive to the calculated syndrome for resolving conflicting estimates that would otherwise preclude said threshold decision, to yield a majority of estimates in agreement from which said threshold decision can be rendered.
Claim 2
Dependent Claim
130 words
A threshold decoder for a digitally coded format of bits containing information and possibly containing transmission errors, comprising means responsive to an incoming format of bits for estimating the value of certain bits in the format, means responsive to the estimates of individual bits for rendering a threshold decision determinative of the information content of successive segments of the format based on the number of estimates in the majority for each segment, means further responsive to the incoming format for calculating the syndrome of a correctable error pattern in the segment of the format under consideration, and means responsive to the calculated syndrome for resolving conflicting estimates that would otherwise preclude said threshold decision, to yield a majority of estimates in agreement from which said threshold decision can be rendered.
Claim 3
Dependent Claim
50 words
A threshold decoder of claim 1, wherein said means for estimating comprises logic circuit means for forming a set of independent estimates of each information bit in said format, each of the estimates in a set being dependent upon a different error bit in combination with the same information bit.
Claim 4
Dependent Claim
31 words
The threshold decoder of claim 2, wherein the set of independent estimates of each information bit contains a number of estimates which is less than the minimum distance of the code.
Claim 5
Dependent Claim
14 words
The threshold decoder of claim 3, wherein the code has an odd minimum distance.
Claim 6
Dependent Claim
29 words
The threshold decoder of claim 1, wherein said means for estimating comprises logic circuit means for forming a set of independent estimates of each error bit in said format.
Claim 7
Dependent Claim
77 words
The threshold decoder of claim 5, further including means responsive to said incoming format for further deriving a single estimate of each information bit in logical combination with an error bit, and means responsive to said single estimate of an information bit and to the threshold decision based on said set of estimates of the respective error bit, for logically combining the threshold decision and the single estimate to eliminate the error bit from the single estimate.
Claim 8
Dependent Claim
27 words
The threshold decoder of claim 1, wherein the digital code of said format is one of a convolutional code, a diffuse convolutional code, and a block code.
Claim 9
Dependent Claim
21 words
The threshold decoder of claim 1, wherein the digital code of said format is at least a double error correcting code.
Claim 10
Dependent Claim
29 words
The threshold decoder of claim 1, further including means responsive to the threshold decision for removing the effects of the binary values resolved by that decision from future decisions.
Claim 11
Dependent Claim
40 words
The threshold decoder of claim 2, wherein the number of independent estimates possible in each set is less than the minimum distance of the code, and wherein the error pattern renders a maximum of one-half of said possible estimates erroneous.
Claim 12
Dependent Claim
185 words
A decoder for convolutional codes in which each segment of a received coded sequence consists of an information bit combined with a bit attributable to transmission error, if any, said decoder comprising means responsive to the received sequence for producing a set of independent estimates of the value of a sufficient part of the combination of bits constituting each received bit to obtain a threshold decision regarding the value of the information bit corresponding to that received bit, wherein the threshold decision is based on a majority vote of the estimates, and the set of estimates is insufficient in number to correct all double error patterns because of a substantial likelihood of ties between the number of correct and incorrect estimates, means further responsive to the received sequence for calculating the syndromes corresponding to correctable error patterns therein, and means responsive to the syndrome calculated for a correctable error pattern pertaining to the received bit being decoded, for extracting therefrom a set of logical functions sufficient to resolve a tie in said threshold decision and thereby to decode the information bit in the received bit.
Claim 13
Dependent Claim
185 words
A decoder for convolutional codes in which each segment of a received coded sequence consists of an information bit combined with a bit attributable to transmission error, if any, said decoder comprising means responsive to the received sequence for producing a set of independent estimates of the value of a sufficient part of the combination of bits constituting each received bit to obtain a threshold decision regarding the value of the information bit corresponding to that received bit, wherein the threshold decision is based on a majority vote of the estimates, and the set of estimates is insufficient in number to correct all double error patterns because of a substantial likelihood of ties between the number of correct and incorrect estimates, means further responsive to the received sequence for calculating the syndromes corresponding to correctable error patterns therein, and means responsive to the syndrome calculated for a correctable error pattern pertaining to the received bit being decoded, for extracting therefrom a set of logical functions sufficient to resolve a tie in said threshold decision and thereby to decode the information bit in the received bit.
Claim 14
Dependent Claim
36 words
The decoder of claim 11, wherein said means for producing a set of estimates comprises means for estimating the value of each information bit in the sequence, whereby the threshold decision itself determines the information bit.
Claim 15
Dependent Claim
42 words
The decoder of claim 11, wherein said means for producing a set of estimates comprises means for estimating the value of each error bit in the sequence, whereby the threshold decision provides sufficient intelligence from which the information bit may be determined.
Claim 16
Dependent Claim
51 words
The decoder of claim 13, wherein is further included means for deriving a single estimate of each information bit as affected by a respective error bit, and means responsive to said single estimate and to said threshold decision for removing the effect of the respective error bit from said single estimate.
Claim 17
Dependent Claim
44 words
The decoder of claim 11, wherein is further provided means responsive to a threshold decision for supplying the results of that decision to both the estimating and syndrome calculating means, to remove from future decisions the effects of items already determined by a decision.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |